WorldWideScience

Sample records for below-ground biotic interactions

  1. Below-ground abiotic and biotic heterogeneity shapes above-ground infection outcomes and spatial divergence in a host-parasite interaction.

    Science.gov (United States)

    Tack, Ayco J M; Laine, Anna-Liisa; Burdon, Jeremy J; Bissett, Andrew; Thrall, Peter H

    2015-09-01

    We investigated the impact of below-ground and above-ground environmental heterogeneity on the ecology and evolution of a natural plant-pathogen interaction. We combined field measurements and a reciprocal inoculation experiment to investigate the potential for natural variation in abiotic and biotic factors to mediate infection outcomes in the association between the fungal pathogen Melampsora lini and its wild flax host, Linum marginale, where pathogen strains and plant lines originated from two ecologically distinct habitat types that occur in close proximity ('bog' and 'hill'). The two habitat types differed strikingly in soil moisture and soil microbiota. Infection outcomes for different host-pathogen combinations were strongly affected by the habitat of origin of the plant lines and pathogen strains, the soil environment and their interactions. Our results suggested that tradeoffs play a key role in explaining the evolutionary divergence in interaction traits among the two habitat types. Overall, we demonstrate that soil heterogeneity, by mediating infection outcomes and evolutionary divergence, can contribute to the maintenance of variation in resistance and pathogenicity within a natural host-pathogen metapopulation. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  2. ABOVE AND BELOW GROUND INTERACTIONS IN THE AGROFORESTAL ASSOCIATION 'RED CEDAR-PERSIAN LIME-CHAYA'

    Directory of Open Access Journals (Sweden)

    Jesús Mao Estanislao Aguilar-Luna

    2011-05-01

    Full Text Available Above and below ground interactions were analyzed in the agroforestal association 'red cedar-Persian lime-chaya', to know the initial optimum planting density (PD, in Quintana Roo, Mexico. Red cedar and Persian lime were placed in a 'Nelder' circle of 3154 m2 which consisted of 20 concentric circles alternating red cedars and Persian limes to 1.50 m apart and 10 plants per circle; chaya rectangular frame was set at 1.50 x 3.00 m, superimposed on the 'Nelder' circle. Defined eight PD 2602 to 3772 pl·ha-1 with 10 repetitions, to evaluate the length of main root (LMR, radical exploration range (RER, below ground interaction (BGI, plant height (PH, crown diameter (CD, above ground interaction (AGI and soil fertility (SF. The growth intraspecific he present statistical difference (P≤0.05 when moving from one PD to another PD, while the growth interespecific manifested different growth habit. The agroforestal association propitious in soil decreased phosphorous ±2 %, and increases organic matter ±14 % and nitrogen ±10 % on all PD. The BGI was increased in direct relation with the PD, reaching its highest value (64±5.8 % to 3772 pl·ha-1; the AGI also increased in direct relation with the PD, its highest value (52±3.1 % went to 3772 pl·ha-1; therefore, to higher PD increased BGI and AGI, at 20 months after planting.

  3. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host-parasite interactions.

    Science.gov (United States)

    Tao, Leiling; Gowler, Camden D; Ahmad, Aamina; Hunter, Mark D; de Roode, Jacobus C

    2015-10-22

    Host-parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host-parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host-parasite systems. © 2015 The Author(s).

  4. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host–parasite interactions

    Science.gov (United States)

    Tao, Leiling; Gowler, Camden D.; Ahmad, Aamina; Hunter, Mark D.; de Roode, Jacobus C.

    2015-01-01

    Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems. PMID:26468247

  5. Ecological relevance of strigolactones in nutrient uptake and other abiotic stresses, and in plant-microbe interactions below ground

    NARCIS (Netherlands)

    Andreo Jimenez, B.; Ruyter-Spira, C.P.; Bouwmeester, H.J.; Lopez-Raez, J.A.

    2015-01-01

    Background Plants are exposed to ever changing and often unfavourable environmental conditions, which cause both abiotic and biotic stresses. They have evolved sophisticated mechanisms to flexibly adapt themselves to these stress conditions. To achieve such adaptation, they need to control and

  6. Biotic Interaction in Space and Time

    DEFF Research Database (Denmark)

    Schmidt, Andreas Kelager

    further enhance the risk of extinction. Maculinea alcon is selected as an umbrella for conservation and numerous aspects of its biology has been studied extensively. This thesis explores the spatio-temporal impact of the tight biotic dependence in this tritrophic interaction system and integrates...... the large body of research with novel methods such as spatial population genetics and macroecological modelling. The results presented in this PhD thesis suggest that inclusion of biotic interactions in macrecological models may completely alter predictions of species’ response to environmental change...... in host ant use as expected, and is an example of a genetic barrier operating on a temporal scale rather than spatial. In chapter II, we developed habitat suitability models for M. alcon and G. pneumonanthe potentially useful in locating undocumented populations and for improving management of them...

  7. Calcium Signalling in Plant Biotic Interactions

    Directory of Open Access Journals (Sweden)

    Didier Aldon

    2018-02-01

    Full Text Available Calcium (Ca2+ is a universal second messenger involved in various cellular processes, leading to plant development and to biotic and abiotic stress responses. Intracellular variation in free Ca2+ concentration is among the earliest events following the plant perception of environmental change. These Ca2+ variations differ in their spatio-temporal properties according to the nature, strength and duration of the stimulus. However, their conversion into biological responses requires Ca2+ sensors for decoding and relaying. The occurrence in plants of calmodulin (CaM but also of other sets of plant-specific Ca2+ sensors such as calmodulin-like proteins (CMLs, Ca2+-dependent protein kinases (CDPKs and calcineurin B-like proteins (CBLs indicate that plants possess specific tools and machineries to convert Ca2+ signals into appropriate responses. Here, we focus on recent progress made in monitoring the generation of Ca2+ signals at the whole plant or cell level and their long distance propagation during biotic interactions. The contribution of CaM/CMLs and CDPKs in plant immune responses mounted against bacteria, fungi, viruses and insects are also presented.

  8. Biotic Interaction in Space and Time

    DEFF Research Database (Denmark)

    Schmidt, Andreas Kelager

    it is highly sensitive to the ongoing environmental change caused by humans. The main drivers for its decline are changed land-use and associated habitat loss or fragmentation, and (in more recent times) drainage, increased eutrophication and lack of appropriate management, but future climate change may...... further enhance the risk of extinction. Maculinea alcon is selected as an umbrella for conservation and numerous aspects of its biology has been studied extensively. This thesis explores the spatio-temporal impact of the tight biotic dependence in this tritrophic interaction system and integrates....... The cross-methodological approaches offer new insight into the conservation of Maculinea alcon and thus aid the future management of this unique butterfly. In chapter I we found two syntopic populations of M. alcon to be genetically differentiated caused by their host plant flower phenology, not differences...

  9. Biotic interactions mediate soil microbial feedbacks to climate change

    Czech Academy of Sciences Publication Activity Database

    Crowther, T. W.; Thomas, S.M.; Maynard, D.S.; Baldrian, Petr; Covey, K.; Frey, S. D.; van Diepen, L. T. A.; Bradford, M.A.

    2015-01-01

    Roč. 112, č. 22 (2015), s. 7033-7038 ISSN 0027-8424 Institutional support: RVO:61388971 Keywords : global change * soil feedback * biotic interaction Subject RIV: EE - Microbiology, Virology Impact factor: 9.423, year: 2015

  10. Nitric oxide and reactive oxygen species in plant biotic interactions.

    Science.gov (United States)

    Scheler, Claudia; Durner, Jörg; Astier, Jeremy

    2013-08-01

    Nitric oxide (NO) and reactive oxygen species (ROS) are important signaling molecules in plants. Recent progress has been made in defining their role during plant biotic interactions. Over the last decade, their function in disease resistance has been highlighted and focused a lot of investigations. Moreover, NO and ROS have recently emerged as important players of defense responses after herbivore attacks. Besides their role in plant adaptive response development, NO and ROS have been demonstrated to be involved in symbiotic interactions between plants and microorganisms. Here we review recent data concerning these three sides of NO and ROS functions in plant biotic interactions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. How plants cope with biotic interactions

    NARCIS (Netherlands)

    Van Dam, N.M.

    2009-01-01

    In their natural environment, plants interact with many different organisms. The nature of these interactions may range from positive, for example interactions with pollinators, to negative, such as interactions with pathogens and herbivores. In this special issue, the contributors provide several

  12. The interactions of ants with their biotic environment.

    Science.gov (United States)

    Chomicki, Guillaume; Renner, Susanne S

    2017-03-15

    This s pecial feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this s pecial feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication. © 2017 The Author(s).

  13. Legumes affect alpine tundra community composition via multiple biotic interactions

    NARCIS (Netherlands)

    Soudzilovskaia, N.A.; Aksenova, A.A.; Makarov, M.I.; Onipchenko, V.G.; Logvinenko, O.A.; Braak, ter C.J.F.; Cornelissen, J.H.C.

    2012-01-01

    The soil engineering function of legumes in natural ecosystems is paramount but associated solely with soil nitrogen (N) subsidies, ignoring concomitant biotic interactions such as competitive or inhibitory effects and exchange between mycorrhizas and rhizobia. We aim to (1) disentangle legume

  14. Biotic interactions govern genetic adaptation to toxicants

    OpenAIRE

    Becker, Jeremias Martin; Liess, Matthias

    2015-01-01

    The genetic recovery of resistant populations released from pesticide exposure is accelerated by the presence of environmental stressors. By contrast, the relevance of environmental stressors for the spread of resistance during pesticide exposure has not been studied. Moreover, the consequences of interactions between different stressors have not been considered. Here we show that stress through intraspecific competition accelerates microevolution, because it enhances fitness differences betw...

  15. Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

    NARCIS (Netherlands)

    Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

    2015-01-01

    There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

  16. Biotic interactions govern genetic adaptation to toxicants

    Science.gov (United States)

    Becker, Jeremias Martin; Liess, Matthias

    2015-01-01

    The genetic recovery of resistant populations released from pesticide exposure is accelerated by the presence of environmental stressors. By contrast, the relevance of environmental stressors for the spread of resistance during pesticide exposure has not been studied. Moreover, the consequences of interactions between different stressors have not been considered. Here we show that stress through intraspecific competition accelerates microevolution, because it enhances fitness differences between adapted and non-adapted individuals. By contrast, stress through interspecific competition or predation reduces intraspecific competition and thereby delays microevolution. This was demonstrated in mosquito populations (Culex quinquefasciatus) that were exposed to the pesticide chlorpyrifos. Non-selective predation through harvesting and interspecific competition with Daphnia magna delayed the selection for individuals carrying the ace-1R resistance allele. Under non-toxic conditions, susceptible individuals without ace-1R prevailed. Likewise, predation delayed the reverse adaptation of the populations to a non-toxic environment, while the effect of interspecific competition was not significant. Applying a simulation model, we further identified how microevolution is generally determined by the type and degree of competition and predation. We infer that interactions with other species—especially strong in ecosystems with high biodiversity—can delay the development of pesticide resistance. PMID:25833856

  17. Biotic-Abiotic Nanoscale Interactions in Biological Fuel Cells

    Science.gov (United States)

    2014-03-28

    such as ATP. This strategy, called oxidative phosphorylation, is embraced by all respiratory microorganisms. Most eukaryotes and many prokaryotes are...AFRL-OSR-VA-TR-2014-0087 (YIP-10) BIOTIC-ABIOTIC NANOSCALE INTERACTIONS IN BIOLOGICAL FUEL CELLS Mohamed El-Naggar UNIVERSITY OF SOUTHERN CALIFORNIA...Interactions in Biological Fuel Cells Award Number: FA9550-10-1-0144 Start Date: 04/15/2010 Program Manager: Patrick O. Bradshaw, PhD Air

  18. Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

    Science.gov (United States)

    Kastman, Erik K; Kamelamela, Noelani; Norville, Josh W; Cosetta, Casey M; Dutton, Rachel J; Wolfe, Benjamin E

    2016-10-18

    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. Decades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS

  19. STRESS ECOLOGY IN FUCUS : ABIOTIC, BIOTIC AND GENETIC INTERACTIONS

    NARCIS (Netherlands)

    Wahl, Martin; Jormalainen, Veijo; Eriksson, Britas Klemens; Coyer, James A.; Molis, Markus; Schubert, Hendrik; Dethier, Megan; Karez, Rolf; Kruse, Inken; Lenz, Mark; Pearson, Gareth; Rohde, Sven; Wikstrom, Sofia A.; Olsen, Jeanine L.; Lesser, M

    2011-01-01

    Stress regimes defined as the synchronous or sequential action of abiotic and biotic stresses determine the performance and distribution of species. The natural patterns of stress to which species are more or less well adapted have recently started to shift and alter under the influence of global

  20. EnviroAtlas - Below Ground Live Tree Biomass Carbon Storage for the Conterminous United States- Forested

    Science.gov (United States)

    This EnviroAtlas dataset includes the average below ground live tree root dry biomass estimate for the Watershed Boundary Dataset (WBD) 12-digit Hydrologic Unit (HUC) in kg/m from the 2000 National Biomass and Carbon Dataset developed by the Woods Hole Research Center. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

  1. Linking macroecology and community ecology: refining predictions of species distributions using biotic interaction networks.

    Science.gov (United States)

    Staniczenko, Phillip P A; Sivasubramaniam, Prabu; Suttle, K Blake; Pearson, Richard G

    2017-06-01

    Macroecological models for predicting species distributions usually only include abiotic environmental conditions as explanatory variables, despite knowledge from community ecology that all species are linked to other species through biotic interactions. This disconnect is largely due to the different spatial scales considered by the two sub-disciplines: macroecologists study patterns at large extents and coarse resolutions, while community ecologists focus on small extents and fine resolutions. A general framework for including biotic interactions in macroecological models would help bridge this divide, as it would allow for rigorous testing of the role that biotic interactions play in determining species ranges. Here, we present an approach that combines species distribution models with Bayesian networks, which enables the direct and indirect effects of biotic interactions to be modelled as propagating conditional dependencies among species' presences. We show that including biotic interactions in distribution models for species from a California grassland community results in better range predictions across the western USA. This new approach will be important for improving estimates of species distributions and their dynamics under environmental change. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  2. Below-ground plant–fungus network topology is not congruent with above-ground plant–animal network topology

    Science.gov (United States)

    Toju, Hirokazu; Guimarães, Paulo R.; Olesen, Jens M.; Thompson, John N.

    2015-01-01

    In nature, plants and their pollinating and/or seed-dispersing animals form complex interaction networks. The commonly observed pattern of links between specialists and generalists in these networks has been predicted to promote species coexistence. Plants also build highly species-rich mutualistic networks below ground with root-associated fungi, and the structure of these plant–fungus networks may also affect terrestrial community processes. By compiling high-throughput DNA sequencing data sets of the symbiosis of plants and their root-associated fungi from three localities along a latitudinal gradient, we uncovered the entire network architecture of these interactions under contrasting environmental conditions. Each network included more than 30 plant species and hundreds of mycorrhizal and endophytic fungi belonging to diverse phylogenetic groups. The results were consistent with the notion that processes shaping host-plant specialization of fungal species generate a unique linkage pattern that strongly contrasts with the pattern of above-ground plant–partner networks. Specifically, plant–fungus networks lacked a “nested” architecture, which has been considered to promote species coexistence in plant–partner networks. Rather, the below-ground networks had a conspicuous “antinested” topology. Our findings lead to the working hypothesis that terrestrial plant community dynamics are likely determined by the balance between above-ground and below-ground webs of interspecific interactions. PMID:26601279

  3. Biotic interactions mediate the expansion of black mangrove (Avicennia germinans) into salt marshes under climate change.

    Science.gov (United States)

    Guo, Hongyu; Zhang, Yihui; Lan, Zhenjiang; Pennings, Steven C

    2013-09-01

    Many species are expanding their distributions to higher latitudes due to global warming. Understanding the mechanisms underlying these distribution shifts is critical for better understanding the impacts of climate changes. The climate envelope approach is widely used to model and predict species distribution shifts with changing climates. Biotic interactions between species, however, may also influence species distributions, and a better understanding of biotic interactions could improve predictions based solely on climate envelope models. Along the northern Gulf of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its distribution grows sympatrically with temperate salt marsh plants in Florida, Louisiana, and Texas. In recent decades, freeze-free winters have led to an expansion of black mangrove into salt marshes. We examined how biotic interactions between black mangrove and salt marsh vegetation along the Texas coast varied across (i) a latitudinal gradient (associated with a winter-temperature gradient); (ii) the elevational gradient within each marsh (which creates different marsh habitats); and (iii) different life history stages of black mangroves (seedlings vs. juvenile trees). Each of these variables affected the strength or nature of biotic interactions between black mangrove and salt marsh vegetation: (i) Salt marsh vegetation facilitated black mangrove seedlings at their high-latitude distribution limit, but inhibited black mangrove seedlings at lower latitudes; (ii) mangroves performed well at intermediate elevations, but grew and survived poorly in high- and low-marsh habitats; and (iii) the effect of salt marsh vegetation on black mangroves switched from negative to neutral as black mangroves grew from seedlings into juvenile trees. These results indicate that the expansion of black mangroves is mediated by complex biotic interactions. A better understanding of the impacts of climate change on ecological

  4. EnviroAtlas - Below Ground Live Tree Biomass Carbon Storage for the Conterminous United States- Forested

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset includes the average below ground live tree root dry biomass estimate for the Watershed Boundary Dataset (WBD) 12-digit Hydrologic Unit...

  5. Tree invasion of a montane meadow complex: temporal trends, spatial patterns, and biotic interactions

    Science.gov (United States)

    Charles B. Halpern; Joseph A. Antos; Janine M. Rice; Ryan D. Haugo; Nicole L. Lang

    2010-01-01

    We combined spatial point pattern analysis, population age structures, and a time-series of stem maps to quantify spatial and temporal patterns of conifer invasion over a 200-yr period in three plots totaling 4 ha. In combination, spatial and temporal patterns of establishment suggest an invasion process shaped by biotic interactions, with facilitation promoting...

  6. Identifying biotic interactions which drive the spatial distribution of a mosquito community.

    Science.gov (United States)

    Golding, Nick; Nunn, Miles A; Purse, Bethan V

    2015-07-14

    Spatial variation in the risk of many mosquito-borne pathogens is strongly influenced by the distribution of communities of suitable vector mosquitoes. The spatial distributions of such communities have been linked to the abiotic habitat requirements of each constituent mosquito species, but the biotic interactions between mosquitoes and other species are less well understood. Determining which fauna restrict the presence and abundance of key mosquito species in vector communities may identify species which could be employed as natural biological control agents. Whilst biotic interactions have been studied in the laboratory, a lack of appropriate statistical methods has prohibited the identification of key interactions which influence mosquito distributions in the field. Joint species distribution models (JSDMs) have recently been developed to identify biotic interactions influencing the distributions of species from empirical data. We apply a JSDM to field data on the spatial distribution of mosquitoes in a UK wetland to identify both abiotic factors and biotic interactions driving the composition of the community. As expected, mosquito larval distributions in this wetland habitat are strongly driven by environmental covariates including water depth, temperature and oxidation-reduction potential. By factoring out these environmental variables, we are able to identify species (ditch shrimp of the genus Palaemonetes and fish) as predators which appear to restrict mosquito distributions. JSDMs offer vector ecologists a way to identify potentially important biotic interactions influencing the distributions of disease vectors from widely available field data. This information is crucial to understand the likely effects of habitat management for vector control and to identify species with the potential for use in biological control programmes. We provide an R package BayesComm to enable the wider application of these models.

  7. The role of reproductive plant traits and biotic interactions in the dynamics of semi-arid plant communities

    NARCIS (Netherlands)

    Pueyo, Y.; Kefi, S.; Diaz-Sierra, R.; Alados, C.L. y; Rietkerk, M.G.

    2010-01-01

    The dynamics of semi-arid plant communities are determined by the interplay between competition and facilitation among plants. The sign and strength of these biotic interactions depend on plant traits. However, the relationships between plant traits and biotic interactions, and the consequences for

  8. Effects of biotic interactions and dispersal on the presence-absence of multiple species

    International Nuclear Information System (INIS)

    Mohd, Mohd Hafiz; Murray, Rua; Plank, Michael J.; Godsoe, William

    2017-01-01

    One of the important issues in ecology is to predict which species will be present (or absent) across a geographical region. Dispersal is thought to have an important influence on the range limits of species, and understanding this problem in a multi-species community with priority effects (i.e. initial abundances determine species presence-absence) is a challenging task because dispersal also interacts with biotic and abiotic factors. Here, we propose a simple multi-species model to investigate the joint effects of biotic interactions and dispersal on species presence-absence. Our results show that dispersal can substantially expand species ranges when biotic and abiotic forces are present; consequently, coexistence of multiple species is possible. The model also exhibits ecologically interesting priority effects, mediated by intense biotic interactions. In the absence of dispersal, competitive exclusion of all but one species occurs. We find that dispersal reduces competitive exclusion effects that occur in no-dispersal case and promotes coexistence of multiple species. These results also show that priority effects are still prevalent in multi-species communities in the presence of dispersal process. We also illustrate the existence of threshold values of competitive strength (i.e. transcritical bifurcations), which results in different species presence-absence in multi-species communities with and without dispersal.

  9. Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

    Science.gov (United States)

    Welk, Astrid; Welk, Erik; Bruelheide, Helge

    2014-01-01

    This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type) responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

  10. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

    International Nuclear Information System (INIS)

    Jones, M.L.M.; Hodges, G.; Mills, G.

    2010-01-01

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

  11. Untangling interactions: do temperature and habitat fragmentation gradients simultaneously impact biotic relationships?

    Science.gov (United States)

    Lakeman-Fraser, Poppy; Ewers, Robert M

    2014-07-22

    Gaining insight into the impact of anthropogenic change on ecosystems requires investigation into interdependencies between multiple drivers of ecological change and multiple biotic responses. Global environmental change drivers can act simultaneously to impact the abundance and diversity of biota, but few studies have also measured the impact across trophic levels. We firstly investigated whether climate (using temperature differences across a latitudinal gradient as a surrogate) interacts with habitat fragmentation (measured according to fragment area and distance to habitat edges) to impact a New Zealand tri-trophic food chain (plant, herbivore and natural enemy). Secondly, we examined how these interactions might differentially impact both the density and biotic processes of species at each of the three trophic levels. We found evidence to suggest that these drivers act non-additively across trophic levels. The nature of these interactions however varied: location synergistically interacted with fragmentation measures to exacerbate the detrimental effects on consumer density; and antagonistically interacted to ameliorate the impact on plant density and on the interactions between trophic levels (herbivory and parasitoid attack rate). Our findings indicate that the ecological consequences of multiple global change drivers are strongly interactive and vary according to the trophic level studied and whether density or ecological processes are investigated. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  12. Above-ground and below-ground plant responses to fertilization in two subarctic ecosystems

    NARCIS (Netherlands)

    Veen, G.F.; Sundqvist, Maja K.; Metcalfe, D.; Wilson, S.D.

    2015-01-01

    Soil nutrient supply is likely to change in the Arctic due to altered process rates associated with climate change. Here, we compare the responses of herbaceous tundra and birch forest understory to fertilization, considering both above- and below-ground responses. We added nitrogen and phosphorus

  13. Fertilization Increases Below-Ground Carbon Sequestration of Loblolly Pine Plantations

    Science.gov (United States)

    K.H. Johnsen; J.R. Butnor; C. Maier; R. Oren; R. Pangle; L. Samuelson; J. Seiler; S.E. McKeand; H.L. Allen

    2001-01-01

    The extent of fertilization of southern pine forests is increasing rapidly; industrial fertilization increased from 16,200 ha per year in 1988, to 344,250 ha in 1998. Fertilization increases stand productivity and can increase carbon (C) sequestration by: 1) increasing above-ground standing C; 2) increasing C stored in forest products; and 3) increasing below-ground...

  14. POLICY FRAMEWORK FOR UTILIZATION AND CONSERVATION OF BELOW-GROUND BIODIVERSITY IN KENYA

    Directory of Open Access Journals (Sweden)

    Celline Achieng

    2009-10-01

    Full Text Available The reasons for the lack of inclusion of below-ground biodiversity in the Kenyan policy and legal framework were sought. Gaps were identified in the relevant sectoral policies and laws in regard to the domestication of the Convention on Biological Diversity (CBD. Below -ground biodiversity had no specific schedule in any of the sectoral laws. Most sectoral laws were particular about the larger biodiversity and soils but had no mention of below-ground biodiversity. Material Transfer Agreements and Material Acquisition Agreements that are regarded as tools of domestication of the CBD to guide transfers, exchanges and acquisition of soil organisms lacked a regulating policy. The lack of regulating policy could be attributed to the delay in approval of draft regulations by the Ministry of Environment while the lack of inclusion of below-ground biodiversity in Kenya’s legal and policy framework could be as a result of lack of awareness and appreciation among stakeholders.

  15. Biotic interactions affect the colonization behavior of aquatic detritivorous macroinvertebrates in a heterogeneous environment

    Science.gov (United States)

    Verschut, Thomas A.; Meineri, Eric; Basset, Alberto

    2015-05-01

    It has previously been suggested that macroinvertebrates actively search for suitable patches to colonize. However, it is not well understood how the spatial arrangement of patches can affect colonization rates. In this study, we determined the importance of the environmental factors (distance, connectivity and resource availability) for patch colonization in an experimental system using Gammarus aequicauda (Amphipoda), Lekanesphaera hookeri (Isopoda) and Ecrobia ventrosa (Gastropoda). Furthermore, we also assessed how the relative importance of each of these environmental factors differed in interactions between the three species. The single species experiments showed that distance was the most important factor for G. aequicauda and E. ventrosa. However, while E. ventrosa preferred patches close to the release point, G. aequicauda strongly preferred patches further from the release point. High resource availability was a strong determinant for the patch colonization of G. aequicauda and L. hookeri. Connectivity was only of moderate importance in the study system for L. hookeri and E. ventrosa. The effects of the environmental factors were strongly affected by interspecific interactions in the multispecies experiments. For G. aequicauda, the distance preference was lowered in the presence of E. ventrosa. Moreover, while for L. hookeri the effect of resource availability was ruled out by the species interactions, resource availability gained importance for E. ventrosa in the presence of any of the other species. Our results suggest a strong link between environmental factors and biotic interactions in the colonization of habitat patches and indicate that the effect of biotic interactions is especially important for species sharing similar traits.

  16. Effects of biotic and abiotic factors on the temporal dynamic of bat-fruit interactions

    Science.gov (United States)

    Laurindo, Rafael de Souza; Gregorin, Renato; Tavares, Davi Castro

    2017-08-01

    Mutualistic interactions between animals and plants vary over time and space based on the abundance of fruits or animals and seasonality. Little is known about this temporal dynamic and the influence of biotic and abiotic factors on the structure of interaction networks. We evaluated changes in the structure of network interactions between bats and fruits in relation to variations in rainfall. Our results suggest that fruit abundance is the main variable responsible for temporal changes in network attributes, such as network size, connectance, and number of interactions. In the same way, temperature positively affected the abundance of fruits and bats. An increase in temperature and alterations in rainfall patterns, due to human induced climate change, can cause changes in phenological patterns and fruit production, with negative consequences to biodiversity maintenance, ecological interactions, and ecosystem functioning.

  17. Interactive Biophysics with Microswimmers: Education, Cloud Experimentation, Programmed Swarms, and Biotic Games

    Science.gov (United States)

    Riedel-Kruse, Ingmar

    Modern biotechnology gets increasingly powerful to manipulate and measure microscopic biophysical processes. Nevertheless, no platform exists to truly interact with these processes, certainly not with the convenience that we are accustomed to from our electronic smart devices. In my talk I will provide the rational for such Interactive Biotechnology and conceptualize its core component, the BPU (biotic processing unit), which is then connected to an according user interface. The biophysical phenomena currently featured on these platforms utilize the phototactic response of motile microorganisms, e.g., Euglena gracilis, resulting in spatio-temporal dynamics from the single cell to the self-organized multi-cellular scale. I will demonstrate multiple platforms, such as scalable biology cloud experimentation labs, tangible museum exhibits, biotic video games, low-cost interactive DIY kits using smartphones, and programming languages for swarm robotics. I will discuss applications for education as well as for professional and citizen science. Hence, we turn traditionally observational microscopy into an interactive experience. I was told that presenting in the educational section does not count against the ''one author - one talk policy'' - so I submit two abstracts. In case of conflict - please contact me: ingmar@stanford.edu.

  18. Metabolic regulation of leaf senescence: interactions of sugar signalling with biotic and abiotic stress responses.

    Science.gov (United States)

    Wingler, A; Roitsch, T

    2008-09-01

    Sugars are important signals in the regulation of plant metabolism and development. During stress and in senescing leaves, sugars often accumulate. In addition, both sugar accumulation and stress can induce leaf senescence. Infection by bacterial and fungal pathogens and attack by herbivores and gall-forming insects may influence leaf senescence via modulation of the sugar status, either by directly affecting primary carbon metabolism or by regulating steady state levels of plant hormones. Many types of biotic interactions involve the induction of extracellular invertase as the key enzyme of an apoplasmic phloem unloading pathway, resulting in a source-sink transition and an increased hexose/sucrose ratio. Induction of the levels of the phytohormones ethylene and jasmonate in biotic interactions results in accelerated senescence, whereas an increase in plant- or pathogen-derived cytokinins delays senescence and results in the formation of green islands within senescing leaves. Interactions between sugar and hormone signalling also play a role in response to abiotic stress. For example, interactions between sugar and abscisic acid (ABA) signalling may be responsible for the induction of senescence during drought stress. Cold treatment, on the other hand, can result in delayed senescence, despite sugar and ABA accumulation. Moreover, natural variation can be found in senescence regulation by sugars and in response to stress: in response to drought stress, both drought escape and dehydration avoidance strategies have been described in different Arabidopsis accessions. The regulation of senescence by sugars may be key to these different strategies in response to stress.

  19. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    Directory of Open Access Journals (Sweden)

    L. E. O. C. Aragão

    2009-12-01

    Full Text Available The net primary productivity (NPP of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1 How do Amazonian forests allocate productivity among its above- and below-ground components? (2 How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error, at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

  20. A below-ground herbivore shapes root defensive chemistry in natural plant populations

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-d-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. PMID:27009228

  1. A below-ground herbivore shapes root defensive chemistry in natural plant populations.

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-03-30

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

  2. Biotic interactions at hydrothermal vents: Recruitment inhibition by the mussel Bathymodiolus thermophilus

    Science.gov (United States)

    Lenihan, H. S.; Mills, S. W.; Mullineaux, L. S.; Peterson, C. H.; Fisher, C. R.; Micheli, F.

    2008-12-01

    The structure and dynamics of marine communities are regulated in part by variation in recruitment. As in other ecosystems, recruitment at deep-sea hydrothermal vents is controlled by the interplay of propagule supply and behavior, gradients in physical-chemical conditions, and biotic interactions during pre- and post-settlement periods. Recent research along the East Pacific Rise indicates that inhibition of recently settled larvae by mobile predators (mainly limpets) influences patterns of recruitment and subsequent community succession. We conducted a manipulative experiment at the same sites (˜2510 m water depth) to test whether high-density assemblages of the mussel Bathymodiolus thermophilus also inhibit recruitment. In a preliminary study, recruitment of vent invertebrates within the faunal zone dominated by B. thermophilus was strikingly different at two sites, East Wall and Worm Hole. East Wall had high densities of mussels but very low total recruitment. In contrast, Worm Hole had few mussels but high recruitment. Using the submersible Alvin, we transplanted a large number of mussels from East Wall to Worm Hole and quantified recruitment on basalt blocks placed in three treatments: (1) naturally high densities of mussels at East Wall; (2) naturally low densities of mussels at Worm Hole; and (3) high densities of transplanted mussels at Worm Hole. After 11 months, a total of 24 taxa had recruited to the basalt blocks. Recruitment was 44-60% lower in the transplanted high-density mussel patch at Worm Hole and the natural high-density patch at East Wall than within the natural low-density patch at Worm Hole. Biotic processes that may have caused the pattern of recruitment observed included predation of larvae via water filtration by mussels, larval avoidance of superior competitors, interference competition, and enhanced predation by species within the mussel-bed community. Our results indicate that biotic interactions affecting recruitment must be

  3. Land-use type and intensity differentially filter traits in above- and below-ground arthropod communities.

    Science.gov (United States)

    Birkhofer, Klaus; Gossner, Martin M; Diekötter, Tim; Drees, Claudia; Ferlian, Olga; Maraun, Mark; Scheu, Stefan; Weisser, Wolfgang W; Wolters, Volkmar; Wurst, Susanne; Zaitsev, Andrey S; Smith, Henrik G

    2017-05-01

    Along with the global decline of species richness goes a loss of ecological traits. Associated biotic homogenization of animal communities and narrowing of trait diversity threaten ecosystem functioning and human well-being. High management intensity is regarded as an important ecological filter, eliminating species that lack suitable adaptations. Below-ground arthropods are assumed to be less sensitive to such effects than above-ground arthropods. Here, we compared the impact of management intensity between (grassland vs. forest) and within land-use types (local management intensity) on the trait diversity and composition in below- and above-ground arthropod communities. We used data on 722 arthropod species living above-ground (Auchenorrhyncha and Heteroptera), primarily in soil (Chilopoda and Oribatida) or at the interface (Araneae and Carabidae). Our results show that trait diversity of arthropod communities is not primarily reduced by intense local land use, but is rather affected by differences between land-use types. Communities of Auchenorrhyncha and Chilopoda had significantly lower trait diversity in grassland habitats as compared to forests. Carabidae showed the opposite pattern with higher trait diversity in grasslands. Grasslands had a lower proportion of large Auchenorrhyncha and Carabidae individuals, whereas Chilopoda and Heteroptera individuals were larger in grasslands. Body size decreased with land-use intensity across taxa, but only in grasslands. The proportion of individuals with low mobility declined with land-use intensity in Araneae and Auchenorrhyncha, but increased in Chilopoda and grassland Heteroptera. The proportion of carnivorous individuals increased with land-use intensity in Heteroptera in forests and in Oribatida and Carabidae in grasslands. Our results suggest that gradients in management intensity across land-use types will not generally reduce trait diversity in multiple taxa, but will exert strong trait filtering within

  4. Ecosystem development in roadside grasslands: Biotic control, plant-soil interactions, and dispersal limitations

    Science.gov (United States)

    Garcia-Palacios, P.; Bowker, M.A.; Maestre, F.T.; Soliveres, S.; Valladares, F.; Papadopoulos, J.; Escudero, A.

    2011-01-01

    Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant-soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0-2, 7-9, and > 20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts (BSCs), and soil microbial functional diversity (soil microorganisms) affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control, and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability, and high soil microbial functional diversity from late-successional stages was associated with high soil fertility. Contrary to our expectations, the indirect effects of plants, mediated by either BSCs or soil microorganisms, were very weak in both regions, suggesting a minor role for plant-soil interactions upon ecosystem development indicators over long periods. Our results suggest that natural vegetation dynamics effectively improved ecosystem development within a time frame of 20 years in the grasslands evaluated. They also indicate that this time could be shortened if management actions focus on: (1) maintaining wellconserved natural areas close to roadsides to enhance plant compositional changes towards late

  5. Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

    Science.gov (United States)

    Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

    2015-05-01

    Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.

  6. The role of biotic interactions in shaping distributions and realised assemblages of species: implications for species distribution modelling

    Science.gov (United States)

    Wisz, Mary Susanne; Pottier, Julien; Kissling, W Daniel; Pellissier, Loïc; Lenoir, Jonathan; Damgaard, Christian F; Dormann, Carsten F; Forchhammer, Mads C; Grytnes, John-Arvid; Guisan, Antoine; Heikkinen, Risto K; Høye, Toke T; Kühn, Ingolf; Luoto, Miska; Maiorano, Luigi; Nilsson, Marie-Charlotte; Normand, Signe; Öckinger, Erik; Schmidt, Niels M; Termansen, Mette; Timmermann, Allan; Wardle, David A; Aastrup, Peter; Svenning, Jens-Christian

    2013-01-01

    Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km2 to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally

  7. Allometric scaling relationship between above- and below-ground biomass within and across five woody seedlings.

    Science.gov (United States)

    Cheng, Dongliang; Ma, Yuzhu; Zhong, Quanling; Xu, Weifeng

    2014-10-01

    Allometric biomass allocation theory predicts that leaf biomass (M L ) scaled isometrically with stem (M S ) and root (M R ) biomass, and thus above-ground biomass (leaf and stem) (M A ) and root (M R ) scaled nearly isometrically with below-ground biomass (root) for tree seedlings across a wide diversity of taxa. Furthermore, prior studies also imply that scaling constant should vary with species. However, litter is known about whether such invariant isometric scaling exponents hold for intraspecific biomass allocation, and how variation in scaling constants influences the interspecific scaling relationship between above- and below-ground biomass. Biomass data of seedlings from five evergreen species were examined to test scaling relationships among biomass components across and within species. Model Type II regression was used to compare the numerical values of scaling exponents and constants among leaf, stem, root, and above- to below-ground biomass. The results indicated that M L and M S scaled in an isometric or a nearly isometric manner with M R , as well as M A to M R for five woody species. Significant variation was observed in the Y-intercepts of the biomass scaling curves, resulting in the divergence for intraspecific scaling and interspecific scaling relationships for M L versus M S and M L versus M R , but not for M S versus M R and M A versus M R . We conclude, therefore, that a nearly isometric scaling relationship of M A versus M R holds true within each of the studied woody species and across them irrespective the negative scaling relationship between leaf and stem.

  8. Space sequestration below ground in old-growth spruce-beech forests – signs for facilitation?

    Directory of Open Access Journals (Sweden)

    Andreas eBolte

    2013-08-01

    Full Text Available Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤ 2 mm by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1 spruce as a central tree, (2 spruce as competitor, (3 beech as a central tree, and (4 beech as competitor. Mean values of life fine root attributes like biomass (FRB, length (FRL, and root area index (RAI were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA, asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

  9. Divergent host preferences of above- and below-ground Culex pipiens mosquitoes and their hybrid offspring.

    Science.gov (United States)

    Fritz, M L; Walker, E D; Miller, J R; Severson, D W; Dworkin, I

    2015-06-01

    Culex pipiens form pipiens and Cx. pipiens form molestus (Diptera: Culicidae) belong to a cosmopolitan taxonomic group known as the Pipiens Assemblage. Hybridization between these forms is thought to contribute to human transmission of West Nile virus (WNV) in North America. Complementary choice and no-choice landing assays were developed to examine host acceptance by North American Cx. pipiens in the laboratory. Populations collected from above- and below-ground sites in suburban Chicago were identified as forms pipiens and molestus using a polymerase chain reaction-based assay. Avian and human host acceptance was then quantified for the two populations, as well as for their hybrid and backcross offspring. No-choice tests were used to demonstrate that both the pipiens and molestus forms were capable of feeding on human and avian hosts. Choice tests were used to demonstrate that form pipiens females were strongly avian-seeking; an individual's probability of accepting the chick host was 85%. Form molestus females were more likely to accept the human host (87%). Rates of host acceptance by F1 and backcross progeny were intermediate to those of their parents. The results suggest that host preferences in Cx. pipiens are genetically determined, and that ongoing hybridization between above- and below-ground populations is an important contributor to epizootic transmission of WNV in North America. © 2015 The Royal Entomological Society.

  10. Local shifts in floral biotic interactions in habitat edges and their effect on quantity and quality of plant offspring

    Science.gov (United States)

    Fenu, Giuseppe; Bernardo, Liliana

    2017-01-01

    Abstract Spatial shifts in insect fauna due to ecological heterogeneity can severely constrain plant reproduction. Nonetheless, data showing effects of insect visit patterns and intensity of mutualistic and/or antagonistic plant–insect interactions on plant reproduction over structured ecological gradients remain scarce. We investigated how changes in flower-visitor abundance, identity and behaviour over a forest-open habitat gradient affect plant biotic interactions, and quantitative and qualitative fitness in the edge-specialist Dianthus balbisii. Composition and behaviour of the insects visiting flowers of D. balbisii strongly varied over the study gradient, influencing strength and patterns of plant biotic interactions (i.e. herbivory and pollination likelihood). Seed set comparison in free- and manually pollinated flowers suggested spatial variations in the extent of quantitative pollen limitation, which appeared more pronounced at the gradient extremes. Such variations were congruent to patterns of flower visit and plant biotic interactions. The analyses on seed and seedling viability evidenced that spatial variation in amount and type of pollinators, and frequency of herbivory affected qualitative fitness of D. balbisii by influencing selfing and outcrossing rates. Our work emphasizes the role of plant biotic interactions as a fine-scale mediator of plant fitness in ecotones, highlighting that optimal plant reproduction can take place into a restricted interval of the ecological gradients occurring at forest edges. Reducing the habitat complexity typical of such transition contexts can threat edge-adapted plants. PMID:28775831

  11. Past tree influence and prescribed fire mediate biotic interactions and community reassembly in a grassland-restoration experiment

    Science.gov (United States)

    Charles B. Halpern; Joseph A. Antos; Donald McKenzie; Annette M. Olson; Lara Souza

    2016-01-01

    1. Woody plant encroachment of grasslands is occurring globally, with profound ecological consequences. Attempts to restore herbaceous dominance may fail if the woody state is resilient or if intervention leads to an alternate, undesirable state. Restoration outcomes often hinge on biotic interactions – particularly on priority effects that inhibit or promote community...

  12. Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change

    NARCIS (Netherlands)

    Tomiolo, S.; Van der Putten, Wim; Tielborger, K.

    2015-01-01

    Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between

  13. Epiphyte-cover on seagrass (Zostera marina L. leaves impedes plant performance and radial O2 loss from the below-ground tissue

    Directory of Open Access Journals (Sweden)

    Kasper Elgetti Brodersen

    2015-08-01

    Full Text Available The O2 budget of seagrasses is a complex interaction between several sources and sinks, which is strongly regulated by light availability and mass transfer over the diffusive boundary layer (DBL surrounding the plant. Epiphyte growth on leaves may thus strongly affect the O2 availability of the seagrass plant and its capability to aerate its rhizosphere as a defence against plant toxins.We used electrochemical and fiber-optic microsensors to quantify the O2 flux, DBL and light microclimate around leaves with and without filamentous algal epiphytes. We also quantified the below-ground radial O2 loss from roots (~1 mm from the root-apex to elucidate how this below-ground oxic microzone was affected by the presence of epiphytes.Epiphyte-cover on seagrass leaves (~21% areal cover resulted in reduced light quality and quantity for photosynthesis, thus leading to reduced plant fitness. A ~4 times thicker diffusive boundary layer around leaves with epiphyte-cover impeded gas (and nutrient exchange with the surrounding water-column and thus the amount of O2 passively diffusing into the leaves in darkness. During light exposure of the leaves, radial oxygen loss from the below-ground tissue was ~2 times higher from plants without epiphyte-cover. In contrast, no O2 was detectable at the surface of the root-cap tissue of plants with epiphyte-cover during darkness, leaving the plants more susceptible to sulphide intrusion.Epiphyte growth on seagrass leaves thus negatively affects the light climate and O2 uptake in darkness, hampering the plants performance and thereby reducing the oxidation capability of its below-ground tissue.

  14. Mind the Roots: Phenotyping Below-Ground Crop Diversity and Its Influence on Final Yield

    Science.gov (United States)

    Nieters, C.; Guadagno, C. R.; Lemli, S.; Hosseini, A.; Ewers, B. E.

    2017-12-01

    Changes in global climate patterns and water regimes are having profound impacts on worldwide crop production. An ever-growing population paired with increasing temperatures and unpredictable periods of severe drought call for accurate modeling of future crop yield. Although novel approaches are being developed in high-throughput, above-ground image phenotyping, the below-ground plant system is still poorly phenotyped. Collection of plant root morphology and hydraulics are needed to inform mathematical models to reliably estimate yields of crops grown in sub-optimal conditions. We used Brassica rapa to inform our model as it is a globally cultivated crop with several functionally diverse cultivars. Specifically, we use 7 different accessions from oilseed (R500 and Yellow Sarson), leafy type (Pac choi and Chinese cabbage), a vegetable turnip, and two Wisconsin Fast Plants (Imb211 and Fast Plant self-compatible), which have shorter life cycles and potentially large differences in allocation to roots. Bi-weekly, we harvested above and below-ground biomass to compare the varieties in terms of carbon allocation throughout their life cycle. Using WinRhizo software, we analyzed root system length and surface area to compare and contrast root morphology among cultivars. Our results confirm that root structural characteristics are crucial to explain plant water use and carbon allocation. The root:shoot ratio reveals a significant (p physiological traits such as gas exchange, chlorophyll content, and chlorophyll a fluorescence. A thorough analysis of the root system will clarify carbon dynamics and hydraulics at the whole-plant level, improving final yield predictions.

  15. Causes of variation in biotic interaction strength and phenotypic selection along an altitudinal gradient.

    Science.gov (United States)

    Mezquida, Eduardo T; Benkman, Craig W

    2014-06-01

    Understanding the causes of variation in biotic interaction strength and phenotypic selection remains one of the outstanding goals of evolutionary ecology. Here we examine the variation in strength of interactions between two seed predators, common crossbills (Loxia curvirostra) and European red squirrels (Sciurus vulgaris), and mountain pine (Pinus uncinata) at and below tree limit in the Pyrenees, and how this translates into phenotypic selection. Seed predation by crossbills increased whereas seed predation by squirrels decreased with increasing elevation and as the canopy became more open. Overall, seed predation by crossbills averaged about twice that by squirrels, and the intensity of selection exerted by crossbills averaged between 2.6 and 7.5 times greater than by squirrels. The higher levels of seed predation by crossbills than squirrels were related to the relatively open nature of most of the forests, and the higher intensity of selection exerted by crossbills resulted from their higher levels of seed predation. However, most of the differences in selection intensity between crossbills and squirrels were the result of habitat features having a greater effect on the foraging behavior of squirrels than of crossbills, causing selection to be much lower for squirrels than for crossbills. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  16. Annual grass invasion in sagebrush-steppe: The relative importance of climate, soil properties and biotic interactions

    Science.gov (United States)

    Bansal, Sheel; Sheley, Roger L.

    2016-01-01

    The invasion by winter-annual grasses (AGs) such as Bromus tectorum into sagebrush steppe throughout the western USA is a classic example of a biological invasion with multiple, interacting climate, soil and biotic factors driving the invasion, although few studies have examined all components together. Across a 6000-km2 area of the northern Great Basin, we conducted a field assessment of 100 climate, soil, and biotic (functional group abundances, diversity) factors at each of 90 sites that spanned an invasion gradient ranging from 0 to 100 % AG cover. We first determined which biotic and abiotic factors had the strongest correlative relationships with AGs and each resident functional group. We then used regression and structural equation modeling to explore how multiple ecological factors interact to influence AG abundance. Among biotic interactions, we observed negative relationships between AGs and biodiversity, perennial grass cover, resident species richness, biological soil crust cover and shrub density, whereas perennial and annual forb cover, tree cover and soil microbial biomass had no direct linkage to AG. Among abiotic factors, AG cover was strongly related to climate (increasing cover with increasing temperature and aridity), but had weak relationships with soil factors. Our structural equation model showed negative effects of perennial grasses and biodiversity on AG cover while integrating the negative effects of warmer climate and positive influence of belowground processes on resident functional groups. Our findings illustrate the relative importance of biotic interactions and climate on invasive abundance, while soil properties appear to have stronger relationships with resident biota than with invasives.

  17. Understanding nutrient dynamics in an African savanna : Local biotic interactions outweigh a major regional rainfall gradient

    NARCIS (Netherlands)

    Veldhuis, Michiel P.; Hulshof, Anneleen; Fokkema, Wimke; Berg, Matty P.; Olff, Han

    Nutrient availability in terrestrial ecosystems has been found to vary along regional climatic and soil gradients and drive variation in plant community composition and vegetation structure. However, more local biotic feedbacks also affect nutrient availability, but their importance in determining

  18. Understanding nutrient dynamics in an African savanna: local biotic interactions outweigh a major regional rainfall gradient

    NARCIS (Netherlands)

    Veldhuis, M.P.; Hulshof, A.; Fokkema, W.; Berg, M.P.; Olff, H.

    2016-01-01

    Nutrient availability in terrestrial ecosystems has been found to vary along regional climatic and soil gradients and drive variation in plant community composition and vegetation structure. However, more local biotic feedbacks also affect nutrient availability, but their importance in determining

  19. A framework for evaluating the influence of climate, dispersal limitation, and biotic interactions using fossil pollen associations across the late Quaternary

    DEFF Research Database (Denmark)

    Blois, Jessica L.; Gotelli, Nicholas J.; Behrensmeyer, Anna K.

    2014-01-01

    Environmental conditions, dispersal lags, and interactions among species are major factors structuring communities through time and across space. Ecologists have emphasized the importance of biotic interactions in determining local patterns of species association. In contrast, abiotic limits, dis...

  20. Adding Biotic Interactions into Paleodistribution Models: A Host-Cleptoparasite Complex of Neotropical Orchid Bees.

    Directory of Open Access Journals (Sweden)

    Daniel Paiva Silva

    Full Text Available Orchid bees compose an exclusive Neotropical pollinators group, with bright body coloration. Several of those species build their own nests, while others are reported as nest cleptoparasites. Here, the objective was to evaluate whether the inclusion of a strong biotic interaction, such as the presence of a host species, improved the ability of species distribution models (SDMs to predict the geographic range of the cleptoparasite species. The target species were Aglae caerulea and its host species Eulaema nigrita. Additionally, since A. caerulea is more frequently found in the Amazon rather than the Cerrado areas, a secondary objective was to evaluate whether this species is increasing or decreasing its distribution given South American past and current climatic conditions. SDMs methods (Maxent and Bioclim, in addition with current and past South American climatic conditions, as well as the occurrences for A. caerulea and E. nigrita were used to generate the distribution models. The distribution of A. caerulea was generated with and without the inclusion of the distribution of E. nigrita as a predictor variable. The results indicate A. caerulea was barely affected by past climatic conditions and the populations from the Cerrado savanna could be at least 21,000 years old (the last glacial maximum, as well as the Amazonian ones. On the other hand, in this study, the inclusion of the host-cleptoparasite interaction complex did not statistically improve the quality of the produced models, which means that the geographic range of this cleptoparasite species is mainly constrained by climate and not by the presence of the host species. Nonetheless, this could also be caused by unknown complexes of other Euglossini hosts with A. caerulea, which still are still needed to be described by science.

  1. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes.

    Science.gov (United States)

    McCormack, M Luke; Dickie, Ian A; Eissenstat, David M; Fahey, Timothy J; Fernandez, Christopher W; Guo, Dali; Helmisaari, Heljä-Sisko; Hobbie, Erik A; Iversen, Colleen M; Jackson, Robert B; Leppälammi-Kujansuu, Jaana; Norby, Richard J; Phillips, Richard P; Pregitzer, Kurt S; Pritchard, Seth G; Rewald, Boris; Zadworny, Marcin

    2015-08-01

    Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally - a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  2. Quantifying below-ground nitrogen of legumes: Optimizing procedures for 15N shoot-labelling

    International Nuclear Information System (INIS)

    Khan, D.F.; Peoples, M.B.; Herridge, D.F.

    2003-01-01

    Quantifying below-ground nitrogen (N) of legumes is fundamental to understanding their effects on soil mineral N fertility and on the N economies of following or companion crops in legume-based rotations. Methodologies based on 15 N-labelling of whole plants with subsequent measurement of 15 N in recovered plant parts and in the root-zone soil have proved promising. We report four glasshouse experiments with objectives to develop appropriate protocols for in situ 15 N labelling of four pulses, faba bean (Vicia faba), chickpea (Cicer arietinum), mung bean (Vigna radiata) and pigeon pea (Cajanus cajan). Treatments included 15 N-urea concentration, feeding technique, leaflet/petiole position, and frequency of feeding. Nitrogen- 15 -labelling via the leaf-flap was best for faba bean, mung and pigeon pea, whilst petiole feeding was best for chickpea, in all cases using 0.2-mL volumes of 0.5% urea (98 atom% 15 N excess). The implications of uneven enrichment of the nodulated roots because of effects of the 15 N-depleted nodules when calculating root-derived N in soil are discussed. (author)

  3. Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

    Science.gov (United States)

    Meier, Courtney L; Bowman, William D

    2008-12-16

    Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

  4. Identifying qualitative effects of different grazing types on below-ground communities and function in a long-term field experiment

    DEFF Research Database (Denmark)

    Macdonald, Catriona A.; Crawley, Michael J.; Wright, Denis J.

    2015-01-01

    for ecosystem functions. The mechanism behind these impacts are likely to be driven by both direct effects of grazing altering the pattern of nutrient inputs and by indirect effects through changes in plant species composition. However, we could not entirely discount that the pesticide used to exclude...... invertebrates may have affected some microbial community measures. Nevertheless, our work illustrates that human activity that affects grazing intensity may affect ecosystem functioning and sustainability, as regulated by multi-trophic interactions between above- and below-ground communities....

  5. Interactive influence of biotic and abiotic cues on the plasticity of preferred body temperatures in a predator–prey system

    Czech Academy of Sciences Publication Activity Database

    Smolinský, Radovan; Gvoždík, Lumír

    2012-01-01

    Roč. 170, č. 1 (2012), s. 47-55 ISSN 0029-8549 R&D Projects: GA ČR GAP506/10/2170; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60930519 Institutional support: RVO:68081766 Keywords : Aeshna * Biotic interactions * Preferred temperature * Reciprocal plasticity * Thermal acclimation * Triturus Subject RIV: EG - Zoology Impact factor: 3.011, year: 2012

  6. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  7. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Science.gov (United States)

    Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  8. A stable isotopic view on lianas' and trees' below ground competition for water

    Science.gov (United States)

    De Deurwaerder, Hannes; Hervé-Fernández, Pedro; Stahl, Clément; Bonal, Damien; Burban, Benoît; Petronelli, Pascal; Boeckx, Pascal; Verbeeck, Hans

    2017-04-01

    Various studies highlight an increase in liana abundance and biomass in the neotropics in the last decades. To date, the reason why this growth form expresses this trend is still unclear. One of the proposed hypotheses ascribes tropical lianas, in comparison to tropical trees, of being able to adapt better to increased drought conditions resulting from climate change. Moreover, lianas presumably have a deeper root system, providing access to deeper soil layers less susceptible for dehydration during drought events. A dual stable water isotopic approach (δ18O and δ2H) enables studying vegetation below ground competition and in combination with Bayesian mixing models can provide insight in the fractional contribution of distinct soil layer depths. In this perspective, precipitation (bulk and through fall), bulk soil (at different depths), stream and xylem water of both lianas and trees were sampled between October 7-13, 2015. The study focusses on two distinct plots differing in soil texture (sand and clay), localized in close vicinity of the Guyana flux tower at Paracou (French Guyana). Our study highlights the erroneous of the deep tap root hypothesis and provides new insights in water and nutrient competition between tropical lianas and trees during dry season. Lianas isotopic signature is enriched compared to those of trees. This can be linked to water source depth and soil seasonal replenishment. Moreover, liana displaying a very active soil surface root activity, efficiently capturing the low amount of dry season precipitation, while trees show to tap the deeper and less drought susceptible soil layers. A strategy, which not only results in a spatial niche separation in the underground competition for water, but it also provides lianas with a definite advantage in nutrient competition.

  9. Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar.

    Science.gov (United States)

    Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V; Kolka, Randall

    2015-01-01

    A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C.

  10. Speciation below ground: Tempo and mode of diversification in a radiation of endogean ground beetles.

    Science.gov (United States)

    Andújar, Carmelo; Pérez-González, Sergio; Arribas, Paula; Zaballos, Juan P; Vogler, Alfried P; Ribera, Ignacio

    2017-11-01

    Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species' habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below-ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil. We studied a species-rich endogean ground beetle lineage, Typhlocharina, including three genera and more than 60 species, as a model for the evolutionary biology of dispersal and speciation in the deep soil. A time-calibrated molecular phylogeny generated from >400 individuals was used to delimit candidate species, to study the accumulation of lineages through space and time by species-area-age relationships and to determine the geographical structure of the diversification using the relationship between phylogenetic and geographic distances across the phylogeny. Our results indicated a small spatial scale of speciation in Typhlocharina and low dispersal capacity combined with sporadic long distance, presumably passive dispersal events that fuelled the speciation process. Analysis of lineage growth within Typhlocharina revealed a richness plateau correlated with the range of distribution of lineages, suggesting a long-term species richness equilibrium mediated by density dependence through limits of habitat availability. The interplay of area- and age-dependent processes ruling the lineage diversification in Typhlocharina may serve as a general model for the evolution of high species diversity in endogean mesofauna. © 2017 John Wiley & Sons Ltd.

  11. The role of biotic interactions in plant community assembly: What is the community species pool?

    Czech Academy of Sciences Publication Activity Database

    Švamberková, E.; Vítová, A.; Lepš, Jan

    2017-01-01

    Roč. 85, NOV 01 (2017), s. 150-156 ISSN 1146-609X Institutional support: RVO:60077344 Keywords : abiotic filter * biotic filter * competitive exclusion Subject RIV: EH - Ecology , Behaviour OBOR OECD: Ecology Impact factor: 1.652, year: 2016 http://www.sciencedirect.com/science/article/pii/S1146609X16303757

  12. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil.

    Science.gov (United States)

    Schroth, M H; Eugster, W; Gómez, K E; Gonzalez-Gil, G; Niklaus, P A; Oester, P

    2012-05-01

    Landfills are a major anthropogenic source of the greenhouse gas methane (CH(4)). However, much of the CH(4) produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH(4) fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH(4) ingress (loading) from the waste body at selected locations. Fluxes of CH(4) into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH(4) concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH(4) fluxes and CH(4) loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH(4) oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH(4) emissions from the test section (daily mean up to ∼91,500μmolm(-2)d(-1)), whereas flux-chamber measurements and CH(4) concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH(4) (uptake up to -380μmolm(-2)d(-1)) during the experimental period. Methane concentration profiles also indicated strong variability in CH(4) loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v(max)∼13mmolL(-1)(soil air)h(-1)) at a location with substantial CH(4) loading. Our results provide a basis to assess spatial and temporal variability of CH(4) dynamics in the complex terrain of a landfill-cover soil. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Above- and below-ground microclimate of grow tubes in an organic mulch-incorporated, raised bed system for blueberry

    Science.gov (United States)

    Grow tubes are well established in forestry and are gaining attention in establishing some woody perennial crops. To date, microclimate descriptions have addressed the above-ground environment, but a mulched raised bed system with organic mulch-incorporated soil requires both above- and below-ground...

  14. Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia

    NARCIS (Netherlands)

    Chen, J.Y.; Bongers, F.; Cao, K.F.; Cai, Z.Q.

    2008-01-01

    Abstract: In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test

  15. Competitive responses of seedlings and understory plants in longleaf pine woodlands: separating canopy influences above and below ground

    Science.gov (United States)

    Stephen D. Pecot; Robert J. Mitchell; Brian J. Palik; Barry Moser; J. Kevin Hiers

    2007-01-01

    A trenching study was used to investigate above- and below-ground competition in a longleaf pine (Pinus palustris P. Mill.) woodland. Trenched and nontrenched plots were replicated in the woodland matrix, at gap edges, and in gap centers representing a range of overstory stocking. One-half of each plot received a herbicide treatment to remove the...

  16. Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L

    Science.gov (United States)

    Anna M. Jensen; Magnus Lof; Emile S. Gardiner

    2011-01-01

    For a tree seedling to successfully establish in dense shrubbery, it must maintain function under heterogeneous resource availability. We evaluated leaf-level acclimation in photosynthetic capacity, seedling-level transpiration, and seedling morphology and growth to gain an understanding of the effects of above- and below-ground competition on Quercus robur seedlings....

  17. Below-ground process responses to elevated CO2 and temperature: a discussion of observations, measurement methods, and models

    Science.gov (United States)

    Elise Pendall; Scott Bridgham; Paul J. Hanson; Bruce Hungate; David W. Kicklighter; Dale W. Johnson; Beverly E. Law; Yiqi Luo; J. Patrick Megonigal; Maria Olsrud; Michael G. Ryan; Shiqiang Wan

    2004-01-01

    Rising atmospheric CO2 and temperatures are probably altering ecosystem carbon cycling, causing both positive and negative feedbacks to climate. Below-ground processes play a key role in the global carbon (C) cycle because they regulate storage of large quantities of C, and are potentially very sensitive to direct and indirect effects of elevated...

  18. How do Humans interact with the Biotic Pump of South America?

    Science.gov (United States)

    Sharma, Ajar; Pande, Saket; Renata Cordeiro Ortigara, Angela; Uhlenbrook, Stefan

    2017-04-01

    The negative effects of the deforestation have been both advertised and down played. However, the effects are far more tangible than what they seem to be. It has been shown that the change in forest cover causes the rainfall patterns to change as the forests work as so-called Biotic Pumps. This changes the water availability in the area by modifying the water balance. Local water balances affect the changes that may take longer to be visible on the larger scales. The Amazon rain forest, one of the most bio-diverse areas worldwide, is an essential part of the biosphere of South America. However, there are clear links between deforestation carried out for agricultural purposes, specifically, Soybean and Sugarcane and the variability in global food prices. Here we analyse the anthropogenic actions that may influence the biotic pump. Variables such as volatility in commodity prices, risk taking capacities, land availability, government subsidies are used to drive the decision making of farmers. These variables are embedded in a lumped biotic pump model made for Brazil, utilizing data from different sources including MODIS, Centro de Previsão do Tempo e Estudos Climáticos (CPTEC), European Centre for Medium-Range Weather Forecasts (ECMWF). The biotic pump model essentially transports atmospheric moisture downwind, part of which falls as rain. The atmospheric moisture 'upwind' accounts for evaporation, incorporating land cover changes in response to land use decisions made by farmers and rainfall. The model is run for scenarios to demonstrate how rain downwind is affected by upwind land cover and provides first insights in to how much rain and productivity (agriculture) downwind is caused by the Amazonian rain forest upwind We then discuss the value of environmental conservation based on marginal productivity analysis, i.e., finding harmony between the conservation of rainforest and the economic growth of the country.

  19. UV-B-mediated changes on below-ground communities associated with the roots of Acer saccharum

    International Nuclear Information System (INIS)

    Klironomos, J.N.; Allen, M.F.

    1995-01-01

    1. Little is known about how exposure to UV-B radiation affects rhizosphere microbes. Rhizosphere organisms are fed primarily by root-derived substrates and fulfil functions such as mineralization, immobilization, decomposition, pathogeneity and improvement of plant nutrition; they form the base of the below-ground food web. 2. In this study, we exposed Sugar Maple (Acer saccharum) seedlings to UV-B radiation in order to determine if UV-B influences the activities of mycorrhizal and non-mycorrhizal fungi, bacteria and microbe-feeding arthropods in the rhizosphere. 3. Below-ground organisms are greatly affected by UV-B radiation. Overall, carbon-flow in the plant soil system was shifted from a mutualistic-closed, mycorrhizal-dominated system to an opportunist-open, saprobe/pathogen-dominated one. (author)

  20. Contribution of above- and below-ground plant traits to the structure and function of grassland soil microbial communities.

    Science.gov (United States)

    Legay, N; Baxendale, C; Grigulis, K; Krainer, U; Kastl, E; Schloter, M; Bardgett, R D; Arnoldi, C; Bahn, M; Dumont, M; Poly, F; Pommier, T; Clément, J C; Lavorel, S

    2014-10-01

    Abiotic properties of soil are known to be major drivers of the microbial community within it. Our understanding of how soil microbial properties are related to the functional structure and diversity of plant communities, however, is limited and largely restricted to above-ground plant traits, with the role of below-ground traits being poorly understood. This study investigated the relative contributions of soil abiotic properties and plant traits, both above-ground and below-ground, to variations in microbial processes involved in grassland nitrogen turnover. In mountain grasslands distributed across three European sites, a correlative approach was used to examine the role of a large range of plant functional traits and soil abiotic factors on microbial variables, including gene abundance of nitrifiers and denitrifiers and their potential activities. Direct effects of soil abiotic parameters were found to have the most significant influence on the microbial groups investigated. Indirect pathways via plant functional traits contributed substantially to explaining the relative abundance of fungi and bacteria and gene abundances of the investigated microbial communities, while they explained little of the variance in microbial activities. Gene abundances of nitrifiers and denitrifiers were most strongly related to below-ground plant traits, suggesting that they were the most relevant traits for explaining variation in community structure and abundances of soil microbes involved in nitrification and denitrification. The results suggest that consideration of plant traits, and especially below-ground traits, increases our ability to describe variation in the abundances and the functional characteristics of microbial communities in grassland soils. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Impacts of Jatropha-based biodiesel production on above and below-ground carbon stocks: A case study from Mozambique

    International Nuclear Information System (INIS)

    Vang Rasmussen, Laura; Rasmussen, Kjeld; Bech Bruun, Thilde

    2012-01-01

    The need to mitigate climate change makes production of liquid biofuels a high priority. Substituting fossil fuels by biodiesel produced from Jatropha curcas has gained widespread attention as Jatropha cultivation is claimed to offer green house gas emission reductions. Farmers respond worldwide to this increasing demand by converting forests into Jatropha, but whether Jatropha-based biodiesel offers carbon savings depends on the carbon emissions that occur when land use is changed to Jatropha. This paper provides an impact assessment of a small-scale Jatropha project in Cabo Delgado, Mozambique. The paper outlines the estimated impacts on above and below-ground carbon stocks when land use is changed to increase Jatropha production. The results show that expansion of Jatropha production will most likely lead to the conversion of miombo forest areas to Jatropha, which implies a reduction in above and below-ground carbon stocks. The carbon debts created by the land use change can be repaid by replacing fossil fuels with Jatropha-based biodiesel. A repayment time of almost two centuries is found with optimistic estimates of the carbon debt, while the use of pessimistic values results in a repayment time that approaches the millennium. - Highlights: ► Demands for biofuels make production of Jatropha-based biodiesel a priority. ► Farmers in Northern Mozambique are likely to convert un-logged miombo to Jatropha. ► Converting miombo to Jatropha creates reductions in above and below-ground carbon. ► It takes 187–966 years to repay emissions from above and below-ground carbon stocks.

  2. The roots of diversity: below ground species richness and rooting distributions in a tropical forest revealed by DNA barcodes and inverse modeling.

    Directory of Open Access Journals (Sweden)

    F Andrew Jones

    Full Text Available Plants interact with each other, nutrients, and microbial communities in soils through extensive root networks. Understanding these below ground interactions has been difficult in natural systems, particularly those with high plant species diversity where morphological identification of fine roots is difficult. We combine DNA-based root identification with a DNA barcode database and above ground stem locations in a floristically diverse lowland tropical wet forest on Barro Colorado Island, Panama, where all trees and lianas >1 cm diameter have been mapped to investigate richness patterns below ground and model rooting distributions.DNA barcode loci, particularly the cpDNA locus trnH-psba, can be used to identify fine and small coarse roots to species. We recovered 33 species of roots from 117 fragments sequenced from 12 soil cores. Despite limited sampling, we recovered a high proportion of the known species in the focal hectare, representing approximately 14% of the measured woody plant richness. This high value is emphasized by the fact that we would need to sample on average 13 m(2 at the seedling layer and 45 m(2 for woody plants >1 cm diameter to obtain the same number of species above ground. Results from inverse models parameterized with the locations and sizes of adults and the species identifications of roots and sampling locations indicates a high potential for distal underground interactions among plants.DNA barcoding techniques coupled with modeling approaches should be broadly applicable to studying root distributions in any mapped vegetation plot. We discuss the implications of our results and outline how second-generation sequencing technology and environmental sampling can be combined to increase our understanding of how root distributions influence the potential for plant interactions in natural ecosystems.

  3. Physical stress, not biotic interactions, preclude an invasive grass from establishing in forb-dominated salt marshes.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available Biological invasions have become the focus of considerable concern and ecological research, yet the relative importance of abiotic and biotic factors in controlling the invasibility of habitats to exotic species is not well understood. Spartina species are highly invasive plants in coastal wetlands; however, studies on the factors that control the success or failure of Spartina invasions across multiple habitat types are rare and inconclusive.We examined the roles of physical stress and plant interactions in mediating the establishment of the smooth cordgrass, Spartina alterniflora, in a variety of coastal habitats in northern China. Field transplant experiments showed that cordgrass can invade mudflats and low estuarine marshes with low salinity and frequent flooding, but cannot survive in salt marshes and high estuarine marshes with hypersaline soils and infrequent flooding. The dominant native plant Suaeda salsa had neither competitive nor facilitative effects on cordgrass. A common garden experiment revealed that cordgrass performed significantly better when flooded every other day than when flooded weekly. These results suggest that physical stress rather than plant interactions limits cordgrass invasions in northern China.We conclude that Spartina invasions are likely to be constrained to tidal flats and low estuarine marshes in the Yellow River Delta. Due to harsh physical conditions, salt marshes and high estuarine marshes are unlikely to be invaded. These findings have implications for understanding Spartina invasions in northern China and on other coasts with similar biotic and abiotic environments.

  4. Above- and below-ground effects of plant diversity depend on species origin

    DEFF Research Database (Denmark)

    Kuebbing, Sara E.; Classen, Aimee Taylor; Sanders, Nate

    2015-01-01

    Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired......-interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased...

  5. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels.

    Science.gov (United States)

    Van der Putten, Wim H; Macel, Mirka; Visser, Marcel E

    2010-07-12

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on biotic interactions and use it to argue that the abundance of species and the direction of selection during climate change vary depending on how their trophic interactions become disrupted. Plant abundance can be controlled by aboveground and belowground multitrophic level interactions with herbivores, pathogens, symbionts and their enemies. We discuss how these interactions may alter during climate change and the resulting species range shifts. We suggest conceptual analogies between species responses to climate warming and exotic species introduced in new ranges. There are also important differences: the herbivores, pathogens and mutualistic symbionts of range-expanding species and their enemies may co-migrate, and the continuous gene flow under climate warming can make adaptation in the expansion zone of range expanders different from that of cross-continental exotic species. We conclude that under climate change, results of altered species interactions may vary, ranging from species becoming rare to disproportionately abundant. Taking these possibilities into account will provide a new perspective on predicting species distribution under climate change.

  6. Biotic interactions mediate the influence of bird colonies on vegetation and soil chemistry at aggregation sites.

    Science.gov (United States)

    Natusch, Daniel James Deans; Lyons, Jessica Ann; Brown, Gregory P; Shine, Richard

    2017-02-01

    Colonial-nesting organisms can strongly alter the chemical and biotic conditions around their aggregation sites, with cascading impacts on other components of the ecosystem. In tropical Australia, Metallic Starlings (Aplonis metallica) nest in large colonies far above the forest canopy, in emergent trees. The ground beneath those trees is open, in stark contrast to the dense foliage all around. We surveyed the areas beneath 27 colony trees (and nearby randomly chosen trees lacking bird colonies) to quantify the birds' impacts on soil and vegetation characteristics, and to test alternative hypotheses about the proximate mechanisms responsible for the lack of live vegetation beneath colony trees. Nutrient levels were greatly elevated beneath colony trees (especially, those with larger colonies), potentially reaching levels toxic to older trees. However, seedlings thrived in the soil from beneath colony trees. The primary mechanism generating open areas beneath colony trees is disturbance by scavengers (feral pigs and native Turkeys) that are attracted in vast numbers to these nutrient hotspots. Seedlings flourished within exclosures inaccessible to vertebrate herbivores, but were rapidly consumed if unprotected. Our results contrast with previous studies of colonies of seabirds on remote islands, where a lack of large terrestrial herbivores results in bird colonies encouraging rather than eliminating vegetation in areas close to the nesting site. In our continental study system, scavengers may rapidly dilute the spatial heterogeneity generated by the massive nutrient subsidy from bird colonies. © 2016 by the Ecological Society of America.

  7. Effects of Grazing on Above- vs. Below-Ground Biomass Allocation of Alpine Grasslands on the Northern Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Chaoxu Zeng

    Full Text Available Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010-2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP was represented by the peak AGB while the belowground net primary productivity (BNPP was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying

  8. Effects of Grazing on Above- vs. Below-Ground Biomass Allocation of Alpine Grasslands on the Northern Tibetan Plateau.

    Science.gov (United States)

    Zeng, Chaoxu; Wu, Jianshuang; Zhang, Xianzhou

    2015-01-01

    Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB) values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010-2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP) was represented by the peak AGB while the belowground net primary productivity (BNPP) was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA) and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced) and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA) analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying human

  9. Interactive biotic and abiotic regulators of soil carbon cycling: evidence from controlled climate experiments on peatland and boreal soils.

    Science.gov (United States)

    Briones, María Jesús I; McNamara, Niall P; Poskitt, Jan; Crow, Susan E; Ostle, Nicholas J

    2014-09-01

    Partially decomposed plant and animal remains have been accumulating in organic soils (i.e. >40% C content) for millennia, making them the largest terrestrial carbon store. There is growing concern that, in a warming world, soil biotic processing will accelerate and release greenhouse gases that further exacerbate climate change. However, the magnitude of this response remains uncertain as the constraints are abiotic, biotic and interactive. Here, we examined the influence of resource quality and biological activity on the temperature sensitivity of soil respiration under different soil moisture regimes. Organic soils were sampled from 13 boreal and peatland ecosystems located in the United Kingdom, Ireland, Spain, Finland and Sweden, representing a natural resource quality range of C, N and P. They were incubated at four temperatures (4, 10, 15 and 20 °C) at either 60% or 100% water holding capacity (WHC). Our results showed that chemical and biological properties play an important role in determining soil respiration responses to temperature and moisture changes. High soil C : P and C : N ratios were symptomatic of slow C turnover and long-term C accumulation. In boreal soils, low bacterial to fungal ratios were related to greater temperature sensitivity of respiration, which was amplified in drier conditions. This contrasted with peatland soils which were dominated by bacterial communities and enchytraeid grazing, resulting in a more rapid C turnover under warmer and wetter conditions. The unexpected acceleration of C mineralization under high moisture contents was possibly linked to the primarily role of fermented organic matter, instead of oxygen, in mediating microbial decomposition. We conclude that to improve C model simulations of soil respiration, a better resolution of the interactions occurring between climate, resource quality and the decomposer community will be required. © 2014 John Wiley & Sons Ltd.

  10. The Genetics Underlying Natural Variation in the Biotic Interactions of Arabidopsis thaliana: The Challenges of Linking Evolutionary Genetics and Community Ecology.

    Science.gov (United States)

    Roux, F; Bergelson, J

    2016-01-01

    In the context of global change, predicting the responses of plant communities in an ever-changing biotic environment calls for a multipronged approach at the interface of evolutionary genetics and community ecology. However, our understanding of the genetic basis of natural variation involved in mediating biotic interactions, and associated adaptive dynamics of focal plants in their natural communities, is still in its infancy. Here, we review the genetic and molecular bases of natural variation in the response to biotic interactions (viruses, bacteria, fungi, oomycetes, herbivores, and plants) in the model plant Arabidopsis thaliana as well as the adaptive value of these bases. Among the 60 identified genes are a number that encode nucleotide-binding site leucine-rich repeat (NBS-LRR)-type proteins, consistent with early examples of plant defense genes. However, recent studies have revealed an extensive diversity in the molecular mechanisms of defense. Many types of genetic variants associate with phenotypic variation in biotic interactions, even among the genes of large effect that tend to be identified. In general, we found that (i) balancing selection rather than directional selection explains the observed patterns of genetic diversity within A. thaliana and (ii) the cost/benefit tradeoffs of adaptive alleles can be strongly dependent on both genomic and environmental contexts. Finally, because A. thaliana rarely interacts with only one biotic partner in nature, we highlight the benefit of exploring diffuse biotic interactions rather than tightly associated host-enemy pairs. This challenge would help to improve our understanding of coevolutionary quantitative genetics within the context of realistic community complexity. © 2016 Elsevier Inc. All rights reserved.

  11. Detecting Below-Ground Processes, Diversity, and Ecosystem Function in a Savanna Ecosystem Using Spectroscopy Across Different Vegetation Layers

    Science.gov (United States)

    Cavender-Bares, J.; Schweiger, A. K.; Madritch, M. D.; Gamon, J. A.; Hobbie, S. E.; Montgomery, R.; Townsend, P. A.

    2017-12-01

    Above-and below-ground plant traits are important for substrate input to the rhizosphere. The substrate composition of the rhizosphere, in turn, affects the diversity of soil organisms, influences soil biochemistry, and water content, and resource availability for plant growth. This has substantial consequences for ecosystem functions, such as above-ground productivity and stability. Above-ground plant chemical and structural traits can be linked to the characteristics of other plant organs, including roots. Airborne imaging spectroscopy has been successfully used to model and predict chemical and structural traits of the above-ground vegetation. However, remotely sensed images capture, almost exclusively, signals from the top of the canopy, providing limited direct information about understory vegetation. Here, we use a data set collected in a savanna ecosystem consisting of spectral measurements gathered at the leaf, the whole plant, and vegetation canopy level to test for hypothesized linkages between above- and below-ground processes that influence root biomass, soil biochemistry, and the diversity of the soil community. In this environment, consisting of herbaceous vegetation intermixed with shrubs and trees growing at variable densities, we investigate the contribution of different vegetation strata to soil characteristics and test the ability of imaging spectroscopy to detect these in plant communities with contrasting vertical structure.

  12. Similar below-ground carbon cycling dynamics but contrasting modes of nitrogen cycling between arbuscular mycorrhizal and ectomycorrhizal forests.

    Science.gov (United States)

    Lin, Guigang; McCormack, M Luke; Ma, Chengen; Guo, Dali

    2017-02-01

    Compared with ectomycorrhizal (ECM) forests, arbuscular mycorrhizal (AM) forests are hypothesized to have higher carbon (C) cycling rates and a more open nitrogen (N) cycle. To test this hypothesis, we synthesized 645 observations, including 22 variables related to below-ground C and N dynamics from 100 sites, where AM and ECM forests co-occurred at the same site. Leaf litter quality was lower in ECM than in AM trees, leading to greater forest floor C stocks in ECM forests. By contrast, AM forests had significantly higher mineral soil C concentrations, and this result was strongly mediated by plant traits and climate. No significant differences were found between AM and ECM forests in C fluxes and labile C concentrations. Furthermore, inorganic N concentrations, net N mineralization and nitrification rates were all higher in AM than in ECM forests, indicating 'mineral' N economy in AM but 'organic' N economy in ECM trees. AM and ECM forests show systematic differences in mineral vs organic N cycling, and thus mycorrhizal type may be useful in predicting how different tree species respond to multiple environmental change factors. By contrast, mycorrhizal type alone cannot reliably predict below-ground C dynamics without considering plant traits and climate. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  13. Biotic interactions enhance survival and fitness in the caddisfly Micropterna sequax (Trichoptera

    NARCIS (Netherlands)

    Westveer, Judith J.; Verdonschot, Piet F.M.; Verdonschot, Ralf C.M.

    2018-01-01

    Patches of coarse particulate organic matter in lowland streams are inhabited by many different macroinvertebrate species, yet knowledge of interactions among the members of these assemblages is scarce. In a mesocosm experiment we aimed to determine the effect of interspecific interactions on

  14. Regulation of copper homeostasis and biotic interactions by microRNA 398b in common bean.

    Directory of Open Access Journals (Sweden)

    Loreto Naya

    Full Text Available MicroRNAs are recognized as important post-transcriptional regulators in plants. Information about the roles of miRNAs in common bean (Phaseolus vulgaris L., an agronomically important legume, is yet scant. The objective of this work was to functionally characterize the conserved miRNA: miR398b and its target Cu/Zn Superoxide Dismutase 1 (CSD1 in common bean. We experimentally validated a novel miR398 target: the stress up-regulated Nodulin 19 (Nod19. Expression analysis of miR398b and target genes -CSD1 and Nod19- in bean roots, nodules and leaves, indicated their role in copper (Cu homeostasis. In bean plants under Cu toxicity miR398b was decreased and Nod19 and CSD1, that participates in reactive oxygen species (ROS detoxification, were up-regulated. The opposite regulation was observed in Cu deficient bean plants; lower levels of CSD1 would allow Cu delivery to essential Cu-containing proteins. Composite common bean plants with transgenic roots over-expressing miR398 showed ca. 20-fold higher mature miR398b and almost negligible target transcript levels as well as increased anthocyanin content and expression of Cu-stress responsive genes, when subjected to Cu deficiency. The down-regulation of miR398b with the consequent up-regulation of its targets was observed in common bean roots during the oxidative burst resulting from short-time exposure to high Cu. A similar response occurred at early stage of bean roots inoculated with Rhizobium tropici, where an increase in ROS was observed. In addition, the miR398b down-regulation and an increase in CSD1 and Nod19 were observed in bean leaves challenged with Sclerotinia scleortiorum fungal pathogen. Transient over-expression of miR398b in Nicotiana benthamiana leaves infected with S. sclerotiorum resulted in enhanced fungal lesions. We conclude that the miR398b-mediated up-regulation of CSD and Nod19 is relevant for common bean plants to cope with oxidative stress generated in abiotic and biotic

  15. Belowground abiotic and biotic heterogeneity shapes aboveground infection outcomes and spatial divergence in a host–parasite interaction

    Science.gov (United States)

    Tack, Ayco J. M.; Laine, Anna-Liisa; Burdon, Jeremy J.; Bissett, Andrew; Thrall, Peter H.

    2015-01-01

    Summary We investigated the impact of belowground and aboveground environmental heterogeneity on the ecology and evolution of a natural plant–pathogen interaction.We combined field measurements and a reciprocal inoculation experiment to investigate the potential for natural variation in abiotic and biotic factors to mediate infection outcomes in the association between the fungal pathogen Melampsora lini and its wild flax host, Linum marginale, where pathogen strains and plant lines originated from two ecologically distinct habitat types that occur in close proximity (‘bog’ and ‘hill’).The two habitat types differed strikingly in soil moisture and soil microbiota. Infection outcomes for different host–pathogen combinations were strongly affected by the habitat of origin of the plant lines and pathogen strains, the soil environment and their interactions. Our results suggested that trade-offs play a key role in explaining the evolutionary divergence in interaction traits among the two habitat types.Overall, we demonstrate that soil heterogeneity, by mediating infection outcomes and evolutionary divergence, can contribute to the maintenance of variation in resistance and pathogenicity within a natural host-pathogen metapopulation. PMID:25872137

  16. Biotic interactions modify multiple-stressor effects on juvenile brown trout in an experimental stream food web.

    Science.gov (United States)

    Bruder, Andreas; Salis, Romana K; Jones, Peter E; Matthaei, Christoph D

    2017-09-01

    Agricultural land use results in multiple stressors affecting stream ecosystems. Flow reduction due to water abstraction, elevated levels of nutrients and chemical contaminants are common agricultural stressors worldwide. Concurrently, stream ecosystems are also increasingly affected by climate change. Interactions among multiple co-occurring stressors result in biological responses that cannot be predicted from single-stressor effects (i.e. synergisms and antagonisms). At the ecosystem level, multiple-stressor effects can be further modified by biotic interactions (e.g. trophic interactions). We conducted a field experiment using 128 flow-through stream mesocosms to examine the individual and combined effects of water abstraction, nutrient enrichment and elevated levels of the nitrification inhibitor dicyandiamide (DCD) on survival, condition and gut content of juvenile brown trout and on benthic abundance of their invertebrate prey. Flow velocity reduction decreased fish survival (-12% compared to controls) and condition (-8% compared to initial condition), whereas effects of nutrient and DCD additions and interactions among these stressors were not significant. Negative effects of flow velocity reduction on fish survival and condition were consistent with effects on fish gut content (-25% compared to controls) and abundance of dominant invertebrate prey (-30% compared to controls), suggesting a negative metabolic balance driving fish mortality and condition decline, which was confirmed by structural equation modelling. Fish mortality under reduced flow velocity increased as maximal daily water temperatures approached the upper limit of their tolerance range, reflecting synergistic interactions between these stressors. Our study highlights the importance of indirect stressor effects such as those transferred through trophic interactions, which need to be considered when assessing and managing fish populations and stream food webs in multiple-stressor situations

  17. Hydrologic, abiotic and biotic interactions: plant density, windspeed, leaf size and groundwater all affect oak water use efficiency

    Science.gov (United States)

    Darin J. Law; Deborah M. Finch

    2011-01-01

    Plant water use in drylands can be complex due to variation in hydrologic, abiotic and biotic factors, particularly near ephemeral or intermittent streams. Plant use of groundwater may be important but is usually uncertain. Disturbances like fire contribute to complex spatiotemporal heterogeneity. Improved understanding of how such hydrologic, abiotic, and biotic...

  18. Synergistic interactions of biotic and abiotic environmental stressors on gene expression.

    Science.gov (United States)

    Altshuler, Ianina; McLeod, Anne M; Colbourne, John K; Yan, Norman D; Cristescu, Melania E

    2015-03-01

    Understanding the response of organisms to multiple stressors is critical for predicting if populations can adapt to rapid environmental change. Natural and anthropogenic stressors often interact, complicating general predictions. In this study, we examined the interactive and cumulative effects of two common environmental stressors, lowered calcium concentration, an anthropogenic stressor, and predator presence, a natural stressor, on the water flea Daphnia pulex. We analyzed expression changes of five genes involved in calcium homeostasis - cuticle proteins (Cutie, Icp2), calbindin (Calb), and calcium pump and channel (Serca and Ip3R) - using real-time quantitative PCR (RT-qPCR) in a full factorial experiment. We observed strong synergistic interactions between low calcium concentration and predator presence. While the Ip3R gene was not affected by the stressors, the other four genes were affected in their transcriptional levels by the combination of the stressors. Transcriptional patterns of genes that code for cuticle proteins (Cutie and Icp2) and a sarcoplasmic calcium pump (Serca) only responded to the combination of stressors, changing their relative expression levels in a synergistic response, while a calcium-binding protein (Calb) responded to low calcium stress and the combination of both stressors. The expression pattern of these genes (Cutie, Icp2, and Serca) were nonlinear, yet they were dose dependent across the calcium gradient. Multiple stressors can have complex, often unexpected effects on ecosystems. This study demonstrates that the dominant interaction for the set of tested genes appears to be synergism. We argue that gene expression patterns can be used to understand and predict the type of interaction expected when organisms are exposed simultaneously to natural and anthropogenic stressors.

  19. Above- and below-ground carbon stocks in an indigenous tree (Mytilaria laosensis) plantation chronosequence in subtropical China.

    Science.gov (United States)

    Ming, Angang; Jia, Hongyan; Zhao, Jinlong; Tao, Yi; Li, Yuanfa

    2014-01-01

    More than 60% of the total area of tree plantations in China is in subtropical, and over 70% of subtropical plantations consist of pure stands of coniferous species. Because of the poor ecosystem services provided by pure coniferous plantations and the ecological instability of these stands, a movement is under way to promote indigenous broadleaf plantation cultivation as a promising alternative. However, little is known about the carbon (C) stocks in indigenous broadleaf plantations and their dependence on stand age. Thus, we studied above- and below-ground biomass and C stocks in a chronosequence of Mytilaria laosensis plantations in subtropical China; stands were 7, 10, 18, 23, 29 and 33 years old. Our assessments included tree, shrub, herb and litter layers. We used plot-level inventories and destructive tree sampling to determine vegetation C stocks. We also measured soil C stocks by analyses of soil profiles to 100 cm depth. C stocks in the tree layer dominated the above-ground ecosystem C pool across the chronosequence. C stocks increased with age from 7 to 29 years and plateaued thereafter due to a reduction in tree growth rates. Minor C stocks were found in the shrub and herb layers of all six plantations and their temporal fluctuations were relatively small. C stocks in the litter and soil layers increased with stand age. Total above-ground ecosystem C also increased with stand age. Most increases in C stocks in below-ground and total ecosystems were attributable to increases in soil C content and tree biomass. Therefore, considerations of C sequestration potential in indigenous broadleaf plantations must take stand age into account.

  20. Study of toxicity and uptake of nanoparticles towards understanding biotic-abiotic interactions

    Science.gov (United States)

    Kosaraju, Karshak

    With the rapid growth in nanotechnology and tremendous applications the engineered nanomaterials (ENs) offer, there is increase in usage of ENs which increases their likelihood of coming in contact with biological systems which include complex beings like humans and other relatively simpler organism like bacteria and other microorganisms. The interaction between the nanomaterials (NMs) and biological systems includes the formation of protein coronas, particle wrapping, intracellular uptake and bio catalytic processes which could have biocompatible or bio adverse outcomes. Understanding these interactions allows the development of predictive relationships between structure and activity that are mainly determined by NM properties such as size, shape, surface chemistry, aggregation, and surface functionality among many others. This understanding will also provide insight towards the design and development of benign nanomaterials. The overarching goal of this dissertation is to understand the influence of the physicochemical characteristics of the NMs and their influence on their uptake and toxicity when they interact with the biological systems (cells and organs). For this purpose, thoroughly characterized NMs will be exposed to a cellular model, A549 cells (alveolar lung epithelial cells), and a mice model (CD-1 mice) through inhalational administration. The effects of NMs on the in vitro and in vivo models will be evaluated by bio- and immuno-chemical methods to understand toxicity, and a combination of analytical spectroscopic and microscopic tools to study uptake. In vivo toxicity assessment will also be performed by using electrocardiogram (ECG) measurements as a tool to study the effects of inhalation of NMs on cardiac response in mice. Through in vivo studies, a novel non-invasive method, Reserve of Refractoriness (RoR), will be introduced as a tool to study cardiotoxicity.

  1. Fire, floods and woody debris: Interactions between biotic and geomorphic processes

    Science.gov (United States)

    Bendix, Jacob; Cowell, C. Mark

    2010-04-01

    Fire and floods interact in the riparian zone as processes that structure plant communities and landforms. Although much of the immediate impact of fire is on the vegetation, fire-related changes in runoff, sediment supply, riparian vegetation, and woody debris volume have ongoing geomorphic impacts on the valley floor. Consequent hydrogeomorphic changes, in turn, affect the composition and distribution of vegetation. This paper reviews these interactions, and provides an example of how fires and floods intersect to supply burnt trees as woody debris. Because the temporal and spatial distribution of woody debris is initially controlled by patterns of tree mortality, ecological disturbances, like fire, can be an important source for pulses of woody debris in riparian systems. To understand these interactions, we examine woody debris inputs 3 years after a wildfire in the riparian gallery forests of the western Transverse Ranges, California. Within our sample of 339 burned stems, snags fell in distinctive patterns: species were variable in susceptibility to falling, and fell at greater rates at sites with greater subsequent flooding. Discordance between the species composition of fallen snags and that of overall burned stems indicates that variability in forest composition must be considered in predicting post-disturbance inputs of woody debris. Variation in snagfall timing among species suggests that woody debris inputs are likely to occur in multiple, sequential pulses after wildfire. The role of flooding is superimposed on this ecological influence, as the timing and spatial variability of floods affect the recruitment of woody debris from the supply of snags created by fire.

  2. Evolutionary history and novel biotic interactions determine plant responses to elevated CO2 and nitrogen fertilization.

    Directory of Open Access Journals (Sweden)

    Rachel Wooliver

    Full Text Available A major frontier in global change research is predicting how multiple agents of global change will alter plant productivity, a critical component of the carbon cycle. Recent research has shown that plant responses to climate change are phylogenetically conserved such that species within some lineages are more productive than those within other lineages in changing environments. However, it remains unclear how phylogenetic patterns in plant responses to changing abiotic conditions may be altered by another agent of global change, the introduction of non-native species. Using a system of 28 native Tasmanian Eucalyptus species belonging to two subgenera, Symphyomyrtus and Eucalyptus, we hypothesized that productivity responses to abiotic agents of global change (elevated CO2 and increased soil N are unique to lineages, but that novel interactions with a non-native species mediate these responses. We tested this hypothesis by examining productivity of 1 native species monocultures and 2 mixtures of native species with an introduced hardwood plantation species, Eucalyptus nitens, to experimentally manipulated soil N and atmospheric CO2. Consistent with past research, we found that N limits productivity overall, especially in elevated CO2 conditions. However, monocultures of species within the Symphyomyrtus subgenus showed the strongest response to N (gained 127% more total biomass in elevated CO2 conditions, whereas those within the Eucalyptus subgenus did not respond to N. Root:shoot ratio (an indicator of resource use was on average greater in species pairs containing Symphyomyrtus species, suggesting that functional traits important for resource uptake are phylogenetically conserved and explaining the phylogenetic pattern in plant response to changing environmental conditions. Yet, native species mixtures with E. nitens exhibited responses to CO2 and N that differed from those of monocultures, supporting our hypothesis and highlighting that both

  3. Total below-ground carbon and nitrogen partitioning of mature black spruce displaying genetic x soil moisture interaction in growth

    Science.gov (United States)

    John E. Major; Kurt H. Johnsen; Debby C. Barsi; Moira Campbell

    2012-01-01

    Total belowground biomass, soil C, and N mass were measured in plots of 32-year-old black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) from four full-sib families studied previously for drought tolerance and differential productivity on a dry and a wet site. Stump root biomass was greater on the wet than on the dry site;...

  4. Diversification and coevolution in brood pollination mutualisms: Windows into the role of biotic interactions in generating biological diversity.

    Science.gov (United States)

    Hembry, David H; Althoff, David M

    2016-10-01

    Brood pollination mutualisms-interactions in which specialized insects are both the pollinators (as adults) and seed predators (as larvae) of their host plants-have been influential study systems for coevolutionary biology. These mutualisms include those between figs and fig wasps, yuccas and yucca moths, leafflowers and leafflower moths, globeflowers and globeflower flies, Silene plants and Hadena and Perizoma moths, saxifrages and Greya moths, and senita cacti and senita moths. The high reciprocal diversity and species-specificity of some of these mutualisms have been cited as evidence that coevolution between plants and pollinators drives their mutual diversification. However, the mechanisms by which these mutualisms diversify have received less attention. In this paper, we review key hypotheses about how these mutualisms diversify and what role coevolution between plants and pollinators may play in this process. We find that most species-rich brood pollination mutualisms show significant phylogenetic congruence at high taxonomic scales, but there is limited evidence for the processes of both cospeciation and duplication, and there are no unambiguous examples known of strict-sense contemporaneous cospeciation. Allopatric speciation appears important across multiple systems, particularly in the insects. Host-shifts appear to be common, and widespread host-shifts by pollinators may displace other pollinator lineages. There is relatively little evidence for a "coevolution through cospeciation" model or that coevolution promotes speciation in these systems. Although we have made great progress in understanding the mechanisms by which brood pollination mutualisms diversify, many opportunities remain to use these intriguing symbioses to understand the role of biotic interactions in generating biological diversity. © 2016 Botanical Society of America.

  5. Below-ground biomass production and allometric relationships of eucalyptus coppice plantation in the central highlands of Madagascar

    International Nuclear Information System (INIS)

    Razakamanarivo, Ramarson H.; Razakavololona, Ando; Razafindrakoto, Marie-Antoinette; Vieilledent, Ghislain; Albrecht, Alain

    2012-01-01

    Short rotations of Eucalyptus plantations under coppice regime are extensively managed for wood production in Madagascar. Nevertheless, little is known about their biomass production and partitioning and their potential in terms of carbon sequestration. If above-ground biomass (AGB) can be estimated based on established allometric relations, below-ground (BGB) estimates are much less common. The aim of this work was to develop allometric equations to estimate biomass of these plantations, mainly for the root components. Data from 9 Eucalyptus robusta stands (47–87 years of plantation age, 3–5 years of coppice-shoot age) were collected and analyzed. Biomass of 3 sampled trees per stand was determined destructively. Dry weight of AGB components (leaves, branches and stems) were estimated as a function of basal area of all shoots per stump and dry weight for BGB components (mainly stump, coarse root (CR) and medium root (MR)) were estimated as a function of stump circumference. Biomass was then computed using allometric equations from stand inventory data. Stand biomass ranged from 102 to 130 Mg ha −1 with more than 77% contained in the BGB components. The highest dry weight was allocated in the stump and in the CR (51% and 42% respectively) for BGB parts and in the stem (69%) for AGB part. Allometric relationships developed herein could be applied to other Eucalyptus plantations which present similar stand density and growing conditions; anyhow, more is needed to be investigated in understanding biomass production and partitioning over time for this kind of forest ecosystem. -- Highlights: ► We studied the potential of old eucalyptus coppices in Madagascar to mitigate global warming. ► Biomass measurement, mainly for below-ground BGB (stump, coarse-medium-and fine roots) was provided. ► BGB allometry relationships for short rotation forestry under coppice were established. ► BGB were found to be important with their 102-130MgC ha -1 (<77% of the C in

  6. Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

    Science.gov (United States)

    Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

    2017-12-01

    Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  7. The Rate and Process of Mangrove Forest Expansion on Above and Below Ground Carbon Relations in Coastal Louisiana

    Science.gov (United States)

    Doyle, T. W.; Pham, T. H.; Reyes, M. R.; Meriwether, J. R.

    2016-02-01

    Recent field studies have documented measureable mangrove expansion landward in tropical zones and poleward in temperate saltmarsh around the northern Gulf of Mexico. Louisiana, in particular, has been recolonized by black mangrove, Avicennia germinans, over a large spatial extent since complete dieback from freeze dating back two decades. Study sites were established near Fourchon, Louisiana to account for the rate and process of marsh/mangrove dominance on carbon burial and elevation change over the past 50 years. Transects were oriented perpendicular from waterway berm of tall and scrub mangrove cover on higher ground grading to low marsh settings of saltmarsh and mixed mangrove ingrowth. Elevation mapping, plant cover and biomass sampling, and soil core dating were conducted to evaluate carbon relations above and below ground. Results showed that sites with tall mangrove have significantly higher above ground biomass than Spartina marsh and mixed marsh/mangrove zone. AG biomass was positively correlated with soil surface elevation and negatively with tidal flood frequency. In addition, tall mangrove zones recorded a twofold increase in soil accretion and carbon burial rates compared with saltmarsh soils based on 137Cs dating. These findings support a positive feedback of mangrove ingrowth and persistence on carbon production and burial allowing higher accretion rates and elevation gains when favored by warmer climate periods lacking or following episodic freeze events.

  8. Application of the biotic ligand model to explain potassium interaction with thallium uptake and toxicity to plankton.

    Science.gov (United States)

    Hassler, Christel S; Chafin, Ryan D; Klinger, Mary Beth; Twiss, Michael R

    2007-06-01

    Competitive interaction between TI(I) and K was successfully predicted by the biotic ligand model (BLM) for the microalga Chlorella sp. (Chlorophyta; University of Toronto Culture Collection strain 522) during 96-h toxicity tests. Because of a greater affinity of T1(I) (log K = 7.3-7.4) as compared to K (log K = 5.3-6.3) for biologically sensitive sites, an excess of 40- to 160-fold of K is required to suppress T1(I) toxic effects on Chlorella sp., regardless of [T1(I)] in solution. Similar excess of K is required to suppress T1(I) toxicity to Synechococcus leopoliensis (Cyanobacteria; University of Texas Culture Collection strain 625) and Brachionus calyciflorus (Rotifera; strain AB-RIF). The mechanism for the mitigating effect of K on T1(I) toxicity was investigated by measuring 204T1(I) cellular uptake flux and efflux in Chlorella sp. Potassium shows a competitive effect on T1(I) uptake fluxes that could be modeled using the BLM-derived stability constants and a Michaelis-Menten relationship. A strong T1 efflux dependent only on the cellular T1 concentration was measured. Although T1 efflux does not explain the effect of K on T1(I) toxicity and uptake, it is responsible for a high turnover of the cellular T1 pool (intracellular half-life = 12-13.5 min). No effect of Na+, Mg2+, or Ca2+ was observed on T1+ uptake, whereas the absence of trace metals (Cu, Co, Mo, Mn, Fe, and Zn) significantly increased T1 uptake and decreased the mitigating effect of K+. The importance of K+ in determining the aquatic toxicity of T1+ underscores the use of ambient K+ concentration in the establishment of T1 water-quality guidelines and the need to consider K in predicting biogeochemical fates of T1 in the aquatic environment.

  9. Interactions among biotic and abiotic factors affect the reliability of tungsten microneedles puncturing in vitro and in vivo peripheral nerves: A hybrid computational approach

    International Nuclear Information System (INIS)

    Sergi, Pier Nicola; Jensen, Winnie; Yoshida, Ken

    2016-01-01

    Tungsten is an elective material to produce slender and stiff microneedles able to enter soft tissues and minimize puncture wounds. In particular, tungsten microneedles are used to puncture peripheral nerves and insert neural interfaces, bridging the gap between the nervous system and robotic devices (e.g., hand prostheses). Unfortunately, microneedles fail during the puncture process and this failure is not dependent on stiffness or fracture toughness of the constituent material. In addition, the microneedles' performances decrease during in vivo trials with respect to the in vitro ones. This further effect is independent on internal biotic effects, while it seems to be related to external biotic causes. Since the exact synergy of phenomena decreasing the in vivo reliability is still not known, this work explored the connection between in vitro and in vivo behavior of tungsten microneedles through the study of interactions between biotic and abiotic factors. A hybrid computational approach, simultaneously using theoretical relationships and in silico models of nerves, was implemented to model the change of reliability varying the microneedle diameter, and to predict in vivo performances by using in vitro reliability and local differences between in vivo and in vitro mechanical response of nerves. - Highlights: • We provide phenomenological Finite Element (FE) models of peripheral nerves to study the interactions with W microneedles • We provide a general interaction-based approach to model the reliability of slender microneedles • We evaluate the reliability of W microneedels to puncture in vivo nerves • We provide a novel synergistic hybrid approach (theory + simulations) involving interactions among biotic and abiotic factors • We validate the hybrid approach by using experimental data from literature

  10. Interactions among biotic and abiotic factors affect the reliability of tungsten microneedles puncturing in vitro and in vivo peripheral nerves: A hybrid computational approach

    Energy Technology Data Exchange (ETDEWEB)

    Sergi, Pier Nicola, E-mail: p.sergi@sssup.it [Translational Neural Engineering Laboratory, The Biorobotics Institute, Scuola Superiore Sant' Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025 (Italy); Jensen, Winnie [Department of Health Science and Technology, Fredrik Bajers Vej 7, 9220 Aalborg (Denmark); Yoshida, Ken [Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, 723 W. Michigan St., SL220, Indianapolis, IN 46202 (United States)

    2016-02-01

    Tungsten is an elective material to produce slender and stiff microneedles able to enter soft tissues and minimize puncture wounds. In particular, tungsten microneedles are used to puncture peripheral nerves and insert neural interfaces, bridging the gap between the nervous system and robotic devices (e.g., hand prostheses). Unfortunately, microneedles fail during the puncture process and this failure is not dependent on stiffness or fracture toughness of the constituent material. In addition, the microneedles' performances decrease during in vivo trials with respect to the in vitro ones. This further effect is independent on internal biotic effects, while it seems to be related to external biotic causes. Since the exact synergy of phenomena decreasing the in vivo reliability is still not known, this work explored the connection between in vitro and in vivo behavior of tungsten microneedles through the study of interactions between biotic and abiotic factors. A hybrid computational approach, simultaneously using theoretical relationships and in silico models of nerves, was implemented to model the change of reliability varying the microneedle diameter, and to predict in vivo performances by using in vitro reliability and local differences between in vivo and in vitro mechanical response of nerves. - Highlights: • We provide phenomenological Finite Element (FE) models of peripheral nerves to study the interactions with W microneedles • We provide a general interaction-based approach to model the reliability of slender microneedles • We evaluate the reliability of W microneedels to puncture in vivo nerves • We provide a novel synergistic hybrid approach (theory + simulations) involving interactions among biotic and abiotic factors • We validate the hybrid approach by using experimental data from literature.

  11. The net effect of abiotic conditions and biotic interactions in a semi-arid ecosystem NE Spain: implications for the management and restoration.

    Science.gov (United States)

    Pueyo, Yolanda; Arroyo, Antonio I.; Saiz, Hugo; Alados, Concepción L.

    2014-05-01

    Degradation in arid and semiarid lands can be irreversible without human intervention, due to a positive plant-soil feedback where the loss of vegetation cover leads to soil degradation, which in turn hampers plant establishment. Human intervention in restoration actions usually involves the amendment of the degraded abiotic conditions, revegetation of bare areas, or both. However, abiotic amelioration is often expensive and too intrusive, and revegetation is not successful in many cases. Biotic interactions between plants, and more specifically facilitation by a "nurse" plant, have been proposed as a new via to take profit of improved abiotic conditions without intervention, and to increase the success rate of revegetation actions. But "nurse" plants can also interfere with others (i.e. by competition for resources or the release of allelopathic compounds), and the net balance between facilitation and interference could depend on plant types involved. We present recent observational and experimental studies performed in the semiarid ecosystems of the Middle Ebro Valley (NE Spain) about the role of abiotic conditions and biotic interactions in the productivity, dynamics and diversity of plant communities under different stress conditions (aridity and grazing). We found that all plant types studied (shrubs and perennial grasses) improved abiotic conditions (soil temperature and water availability for plants) with respect to open areas. However, only some shrubs (mainly Salsola vermiculata) had a positive net balance in the biotic interactions between plants, while other shrubs (Artemisia herba-alba) and perennial grasses (Lygeum spartum) showed interference with other plants. Moreover, the net balance between facilitation and interference among plants in the community shifted from competitive to neutral or from neutral to facilitative with increasing aridity. Grazing status did not strongly change the net biotic interactions between plants. Our results suggest that

  12. The presence of a below-ground neighbour alters within-plant seed size distribution in Phaseolus vulgaris.

    Science.gov (United States)

    Chen, Bin J W; During, Heinjo J; Vermeulen, Peter J; Anten, Niels P R

    2014-10-01

    Considerable variation in seed size commonly exists within plants, and is believed to be favoured under natural selection. This study aims to examine the extent to which seed size distribution depends on the presence of competing neighbour plants. Phaseolus vulgaris plants rooting with or without a conspecific neighbour were grown in soil with high or low nutrient availability. Seeds were harvested at the end of the growth cycle, the total nitrogen and phosphorus invested in seed production were measured and within-plant seed size distribution was quantified using a set of statistical descriptors. Exposure to neighbours' roots induced significant changes in seed size distribution. Plants produced proportionally more large seeds and fewer small ones, as reflected by significant increases in minimal seed size, mean seed size, skewness and Lorenz asymmetry coefficient. These effects were different from, and in several cases opposite to, the responses when the soil nutrient level was reduced, and were significant after correction for the amount of resources invested in seed production. Below-ground neighbour presence affects within-plant seed size distribution in P. vulgaris. This effect appears to be non-resource-mediated, i.e. to be independent of neighbour-induced effects on resource availability. It implies that, based on current environmental cues, plants can make an anticipatory adjustment of their investment strategy in offspring as an adaptation to the local environment in the future. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. A family of null models to distinguish between environmental filtering and biotic interactions in functional diversity patterns

    Czech Academy of Sciences Publication Activity Database

    Chalmandrier, L.; Münkemüller, T.; Gallien, L.; de Bello, Francesco; Mazel, F.; Lavergne, S.; Thuiller, W.

    2013-01-01

    Roč. 24, č. 5 (2013), 853-864 ISSN 1100-9233 R&D Projects: GA ČR GAP505/12/1296 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : Nullmodels * Simulated communities * Biotic and abiotic filtering Subject RIV: EF - Botanics Impact factor: 3.372, year: 2013

  14. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Cochavi, Amnon; Rapaport, Tal; Gendler, Tania; Karnieli, Arnon; Eizenberg, Hanan; Rachmilevitch, Shimon; Ephrath, Jhonathan E

    2017-01-01

    Broomrape ( Orobanche and Phelipanche spp.) parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR) hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R). The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg -1 seeds) and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana parasitism. Analysis of

  15. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.

    Directory of Open Access Journals (Sweden)

    Amnon Cochavi

    2017-06-01

    Full Text Available Broomrape (Orobanche and Phelipanche spp. parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R. The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg-1 seeds and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana

  16. Allometry and partitioning of above- and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes

    International Nuclear Information System (INIS)

    Kuyah, Shem; Dietz, Johannes; Muthuri, Catherine; Noordwijk, Meine van; Neufeldt, Henry

    2013-01-01

    Farmers in developing countries are one of the world's largest and most efficient producers of sequestered carbon. However, measuring, monitoring and verifying how much carbon trees in smallholder farms are removing from the atmosphere has remained a great challenge in developing nations. Devising a reliable way for measuring carbon associated with trees in agricultural landscapes is essential for helping smallholder farmers benefit from emerging carbon markets. This study aimed to develop biomass equations specific to dominant eucalyptus species found in agricultural landscapes in Western Kenya. Allometric relationships were developed by regressing diameter at breast height (DBH) alone or DBH in combination with height, wood density or crown area against the biomass of 48 trees destructively sampled from a 100 km 2 site. DBH alone was a significant predictor variable and estimated aboveground biomass (AGB) with over 95% accuracy. The stems, branches and leaves formed up to 74, 22 and 4% of AGB, respectively, while belowground biomass (BGB) of the harvested trees accounted for 21% of the total tree biomass, yielding an overall root-to-shoot ratio (RS) of 0.27, which varied across tree size. Total tree biomass held in live Eucalyptus trees was estimated to be 24.4 ± 0.01 Mg ha −1 , equivalent to 11.7 ± 0.01 Mg of carbon per hectare. The equations presented provide useful tools for estimating tree carbon stocks of Eucalyptus in agricultural landscapes for bio-energy and carbon accounting. These equations can be applied to Eucalyptus in most agricultural systems with similar agro-ecological settings where tree growth parameters would fall within ranges comparable to the sampled population. -- Highlights: ► Equation with DBH alone estimated aboveground biomass with about 95% accuracy. ► Local generic equations overestimated above- and below-ground biomass by 10 and 48%. ► Height, wood density and crown area data did not improve model accuracy. ► Stems

  17. Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

    Science.gov (United States)

    Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

    2017-12-01

    The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

  18. No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

    Science.gov (United States)

    Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

    2017-06-17

    Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

  19. Luxury consumption of soil nutrients: a possible competitive strategy in above-ground and below-ground biomass allocation and root morphology for slow-growing arctic vegetation?

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Gough, L.; Hobbie, S.E.; Shaver, G.R.

    2003-01-01

    1 A field-experiment was used to determine how plant species might retain dominance in an arctic ecosystem receiving added nutrients. We both measured and modelled the above-ground and below-ground biomass allocation and root morphology of non-acidic tussock tundra near Toolik Lake, Alaska, after 4

  20. Impacts of an Invasive Non-Native Annual Weed, Impatiens glandulifera, on Above- and Below-Ground Invertebrate Communities in the United Kingdom

    Science.gov (United States)

    Tanner, Robert A.; Varia, Sonal; Eschen, René; Wood, Suzy; Murphy, Sean T.; Gange, Alan C.

    2013-01-01

    Vegetation community composition and the above- and below-ground invertebrate communities are linked intrinsically, though few studies have assessed the impact of non-native plants on both these parts of the community together. We evaluated the differences in the above- (foliage- and ground-dwelling) and below-ground invertebrate communities in nine uninvaded plots and nine plots invaded by the annual invasive species Impatiens glandulifera, in the UK during 2007 and 2008. Over 139,000 invertebrates were identified into distinct taxa and categorised into functional feeding groups. The impact of I. glandulifera on the vegetation and invertebrate community composition was evaluated using multivariate statistics including principal response curves (PRC) and redundancy analysis (RDA). In the foliage-dwelling community, all functional feeding groups were less abundant in the invaded plots, and the species richness of Coleoptera and Heteroptera was significantly reduced. In the ground-dwelling community, herbivores, detritivores, and predators were all significantly less abundant in the invaded plots. In contrast, these functional groups in the below-ground community appeared to be largely unaffected, and even positively associated with the presence of I. glandulifera. Although the cover of I. glandulifera decreased in the invaded plots in the second year of the study, only the below-ground invertebrate community showed a significant response. These results indicate that the above- and below-ground invertebrate communities respond differently to the presence of I. glandulifera, and these community shifts can potentially lead to a habitat less biologically diverse than surrounding native communities; which could have negative impacts on higher trophic levels and ecosystem functioning. PMID:23840648

  1. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta Forests.

    Directory of Open Access Journals (Sweden)

    Anne C S McIntosh

    Full Text Available Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs and multiple carbon-source substrate-induced respiration (MSIR of the forest floor microbial community environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis showed that two above-ground (mean tree diameter, litter cover and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs properties were associated with variation in understory plant community composition. These results provide

  2. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests.

    Science.gov (United States)

    McIntosh, Anne C S; Macdonald, S Ellen; Quideau, Sylvie A

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  3. Above- and Belowground Trophic Interactions on Creeping Thistle (Cirsium arvense) in High- and Low-Diversity Plant Communities: Potential for Biotic Resistance?

    NARCIS (Netherlands)

    Bezemer, T.M.; Graça, O.; Rousseau, P.; Van der Putten, W.H.

    2004-01-01

    The capacity of local communities to control introduced plants is called biotic resistance. Biotic resistance has been almost exclusively tested for plant competition and aboveground herbivores and pathogens, while neglecting root herbivores and soil pathogens. Here, we present biotic resistance by

  4. Above- and Belowground Trophic Interactions on Creeping Thistle (Cirsium arvense) in High- and Low-Diversity Plant Communities: Potential for Biotic Resistance?

    NARCIS (Netherlands)

    Bezemer, T.M.; Graça, O.; Rousseau, P.; Putten, van der W.H.

    2004-01-01

    The capacity of local communities to control introduced plants is called biotic resistance. Biotic resistance has been almost exclusively tested for plant competition and above-ground herbivores and pathogens, while neglecting root herbivores and soil pathogens. Here, we present biotic resistance by

  5. Above- and below-ground effects of plant diversity depend on species origin: an experimental test with multiple invaders.

    Science.gov (United States)

    Kuebbing, Sara E; Classen, Aimée T; Sanders, Nathan J; Simberloff, Daniel

    2015-11-01

    Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity-interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased productivity: positive selection effect in nonnative communities and positive complementarity effect in native communities. Seedling establishment was 46% lower in nonnative than in native communities and was correlated with the average selection effect. Interspecific interactions contributed to productivity patterns, but the specific types of interactions differed between native and nonnative communities. These results reinforce findings that the diversity-productivity mechanisms in native and nonnative communities differ and are the first to show that these mechanisms can influence seedling establishment and that different types of interactions influence diversity-productivity relationships. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  6. Drought as a modifier of interaction between adult beech and spruce - impacts on tree water use, C budgets and biotic interactions above- and belowground

    Science.gov (United States)

    Grams, Thorsten

    2017-04-01

    Understanding biotic interactions among tree species with their microbial associates under drought will be crucial for silviculture in meeting ecological challenges of the future. This contribution gives an overview on a project integrating a throughfall-exclusion experiment (TEE) on adult trees with a natural precipitation gradient (PGR) in central European forests. Focus is on drought affecting species interaction above and belowground, including associated ectomycorrhizal (ECM) communities. Study objects are pure and mixed forests dominated by adult European beech and Norway spruce trees (c. 70-years old). At the throughfall-exclusion experiment (TEE), trees are readily accessible via scaffolding and canopy crane (Kranzberg Forest, southern Germany). Effects of experimentally induced, repeated summer drought are assessed with roughly 100 trees assigned to a total of 12 plots (Kranzberg forest ROOF experiment, kroof.wzw.tum.de). The summer drought treatment started in 2014 and was repeated in 2015 and 2106. The focus on species interaction is intensified by a parallel study along a natural precipitation gradient with plot triplets of monocultures and mixed cultures of European beech and Norway spruce at each of the five study sites. Complementary resource use, effects of competitive vs. facilitation and related changes in ECM communities are exemplified for the two tree species of contrasting foliage (i.e. deciduous vs. evergreen) and stomatal sensitivity to drought (i.e. an-isohydric vs. isohydric behavior). At the TEE site, precipitation throughfall was completely excluded from early spring to late fall (i.e. March to November), resulting in pre-dawn leaf water potentials of both beech and spruce as low as -2.5 MPa. Despite significant reductions in growth and rate of photosynthesis by up to 80% under drought, NSC budget of trees was hardly affected. Moreover, phloem functionality, tested as phloem transport velocity through 13C-labeling of recent

  7. Toward Modeling the Resistance and Resilience of "Below-ground" Fungal Communities: A Mechanistic and Trait-Based Approach.

    Science.gov (United States)

    Falconer, Ruth E; Otten, Wilfred; White, Nia A

    2015-01-01

    The role of fungi in shaping ecosystems is well evidenced and there is growing recognition of their importance among scientists and the general public. Establishing and separating the role of key local (soil chemical, biological, and physical properties) and global (climate, dispersal limitation) drivers in fungal community structure and functioning is currently a source of frustration to mycologists. The quest to determine niche processes and environmental characteristics shaping fungal community structure, known to be important for plant and animal communities, is proving difficult, resulting in the acknowledgment that niche neutral processes (climate, dispersal limitations) may dominate. The search for predictable patterns in fungal community structure may have been restricted as the "appropriate" scales at which to measure community structure and characterize the environment have not been fully determined yet, and the focus on taxonomy makes it difficult to link environmental characteristics to fungal traits. While key determinants of microbial community composition have been uncovered for some functional groups, the differential response of functional groups is largely unknown. Before we can truly understand what drives the development of microbial community structure, an understanding of the autecology of major fungal taxa and how they interact with their immediate environment (from the micro- up to kilometer scale) is urgently needed. Furthermore, key information and empirical data is missing at the microscale due to experimental difficulties in mapping this heterogeneous and opaque environment. We therefore present a framework that would help generate this much-needed empirical data and information at the microscale, together with modeling approaches to link the spatial and temporal scales. The latter is important as we propose that there is much to be gained by linking our understanding of fungal community responses across scales, in order to develop

  8. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels

    NARCIS (Netherlands)

    Van der Putten, W.H.; Macel, M.; Visser, M.E.

    2010-01-01

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on

  9. Interaction of rock, water, and plants in central Siberia (Russia) dominated by continuous permafrost: biotic versus abiotic fluxes

    Science.gov (United States)

    Viers, J.; Pokrovsky, O. S.; Prokushkin, A. S.; Beaulieu, E.; Dupre, B.

    2009-12-01

    -ground biomass in this region. We analyzed large number of soils, larch needles, mosses, dwarf shrubs and waters (from soils and rivers) collected in the various local environments. Plant biomass was regularly collected from May to September 2007. Our efforts focus on weathering processes and elements transport mechanisms between the different chemical reservoirs (soil and litter, plants, atmosphere) using a multidisciplinary approach. The aim of the presentation is : i) to propose a conceptual model of the present-day “biogeochemical” functioning of basaltic watershed located in central Siberia, ii) to evaluate biotic and abiotic element fluxes from the watershed, and iii) to assess the effect of global warming through the local comparison of the north-facing and south-facing environments. The role of plants dominated by larches, dwarf shrubs and mosses will be particularly considered.

  10. Process-based species pools reveal the hidden signature of biotic interactions amid the influence of temperature filtering

    DEFF Research Database (Denmark)

    Lessard, Jean-Philippe; Weinstein, Ben G.; Borregaard, Michael Krabbe

    2016-01-01

    A persistent challenge in ecology is to tease apart the in-fluence of multiple processes acting simultaneously and interacting in complex ways to shape the structure of species assemblages. We implement a heuristic approach that relies on explicitly defining spe-cies pools and permits assessment ...

  11. Three-way interaction between biological control insects, a congener and their shared parasitoid: Evidence of biotic resistance

    Science.gov (United States)

    Invasive plants are one of the strongest drivers of species extinctions. Weed biological control offers a sustainable and safe means of long-term population reduction of their target. Herbivores introduced for the control of invasive plants interact with the native community in addition to the top-d...

  12. Recommendations to the NRC for review criteria for alternative methods of low-level radioactive waste disposal: Task 2a, Below-ground vaults

    International Nuclear Information System (INIS)

    Denson, R.H.; Bennett, R.D.; Wamsley, R.M.; Bean, D.L.; Ainsworth, D.L.

    1987-12-01

    The US Army Engineer Waterways Experiment Station (WES) and the US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the below-ground vault (BGV) alternative method of low-level radioactive waste (LLW) disposal. A BGV is a reinforced concrete vault (floor, walls, and roof) placed underground below the frost line, and above the water table, surrounded by filter blanket and drainage zones and covered with a low permeability earth layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the BGV structure through material quality and durability considerations. Specific design review criteria have been developed in detail for seven of the eight major categories. 59 refs., 14 figs., 2 tabs

  13. Biomass and morphology of fine roots in temperate broad-leaved forests differing in tree species diversity: is there evidence of below-ground overyielding?

    Science.gov (United States)

    Meinen, Catharina; Hertel, Dietrich; Leuschner, Christoph

    2009-08-01

    Biodiversity effects on ecosystem functioning in forests have only recently attracted increasing attention. The vast majority of studies in forests have focused on above-ground responses to differences in tree species diversity, while systematic analyses of the effects of biodiversity on root systems are virtually non-existent. By investigating the fine root systems in 12 temperate deciduous forest stands in Central Europe, we tested the hypotheses that (1) stand fine root biomass increases with tree diversity, and (2) 'below-ground overyielding' of species-rich stands in terms of fine root biomass is the consequence of spatial niche segregation of the roots of different species. The selected stands represent a gradient in tree species diversity on similar bedrock from almost pure beech forests to medium-diverse forests built by beech, ash, and lime, and highly-diverse stands dominated by beech, ash, lime, maple, and hornbeam. We investigated fine root biomass and necromass at 24 profiles per stand and analyzed species differences in fine root morphology by microscopic analysis. Fine root biomass ranged from 440 to 480 g m(-2) in the species-poor to species-rich stands, with 63-77% being concentrated in the upper 20 cm of the soil. In contradiction to our two hypotheses, the differences in tree species diversity affected neither stand fine root biomass nor vertical root distribution patterns. Fine root morphology showed marked distinctions between species, but these root morphological differences did not lead to significant differences in fine root surface area or root tip number on a stand area basis. Moreover, differences in species composition of the stands did not alter fine root morphology of the species. We conclude that 'below-ground overyielding' in terms of fine root biomass does not occur in the species-rich stands, which is most likely caused by the absence of significant spatial segregation of the root systems of these late-successional species.

  14. Uprooting force balance for pioneer woody plants: A quantification of the relative contribution of above- and below-ground plant architecture to uprooting susceptibility

    Science.gov (United States)

    Bywater-Reyes, S.; Wilcox, A. C.; Lightbody, A.; Skorko, K.; Stella, J. C.

    2012-12-01

    Cottonwood (Populus), willow (Salix), and tamarisk (Tamarix) populate riparian areas in many dryland regions, and their recruitment depends heavily on hydrogeomorphic conditions. The survival of pioneer woody seedlings depends in part on the establishment of root systems capable of anchoring plants in subsequent floods, and this root system development in turn influences the cohesion that plants provide to bars. The factors influencing the anchoring ability and resistance to scour of woody seedlings include plant frontal area and flexibility, root structure, and water table elevation. This study aims to quantify the factors comprising the force balance to uproot woody seedlings and saplings in two field sites characterized by different hydrologic conditions. The Bill Williams River (AZ) is an impounded river with elevated water table elevations produced by dam-released base flows. The Bitterroot River (MT) is an unimpounded river with a snowmelt hydrograph and seasonal fluctuations in river and water table elevation. We simulate uprooting from flooding events by saturating substrates and applying force near the base of the plant in a lateral, downstream direction until uprooting occurs, for a range of plant sizes but with a focus on small (plants, with cottonwood and tamarisk seedlings showing greater variability than willow. In contrast, root length and stem diameter are only weakly correlated with pull-out force. By combining pull test results with measurements of geomorphic and groundwater conditions, this study provides insights into the relative contribution of a plant's above-ground and below-ground architecture to uprooting potential and into the feedbacks between vegetation and morphodynamics on river bars.

  15. Assessment of Above- and Below-ground Competition between Sesame (Sesamume indicum L. and Pigweed (Amaranthus retroflexus and Its Effects on Sesame Yield and Yield Components

    Directory of Open Access Journals (Sweden)

    A.J Yanegh

    2013-08-01

    Full Text Available This study carried out in a factorial layout on completely randomaized block design with three replications, to evaluate the above- and below- ground competition between sesame (Sesamum indicum and pigweed (Amaranthus retroflexus, and their impacts on sesame yield and yield component. The experimental treatments were all combination of crop-weed competition (shoot competition, root competition and root-shoot competition and sesame plant densitys (1, 2 and 4 plant per pot. Plants were sown in plastic pots (24 cm diameter and 28 cm height in year 2010, at feild of Ferdowsi University of Mashhad. For study the shoot competition of sesame-pigweed, the roots were separated by plastic when the pots were filled with soil before sowing the seeds. Three weeks after emerging, shoots of plants were separated vertical barrier (30 x 70 cm for studing root competition. Results showed that competition treatments had a significant effect on seed weight per plant and yield components except 1000 seed weight. Among competition produced higher yield and yield components compared to othere treatments. However, sesame and pigweed biological weight in root-shoot competition was 2.6 and 13.7 respectively, that was higher than other competition treatments and was significant. Capsule number in main and sub branches, capsule number in plant, seed number in capsule and seed number in plant in complete competition treatment was 15, 2.58, 17.5, 43.7 and 693.89 respectively, that was higher than other treatments and differences among them was significant. Sesame density also had a significant effect on seed weight per plant and yield components. When low density were used (one plant, yield and yield components was more, therefore in one plant per pot density biological weight of sesame was 3.82 gr, and in higher densities the mentioned traits decreased significantly.

  16. Evaluation of carbon stocks in above- and below-ground biomass in Central Africa: case study of Lesio-louna tropical rainforest of Congo

    Science.gov (United States)

    Liu, X.; Ekoungoulou, R.; Loumeto, J. J.; Ifo, S. A.; Bocko, Y. E.; Koula, F. E.

    2014-07-01

    The study was aimed to estimate the carbon stocks of above- and below-ground biomass in Lesio-louna forest of Congo. The methodology of allometric equations was used to measure the carbon stocks of Lesio-louna natural forest. We are based precisely on the model II which is also called non-destructive method or indirect method of measuring carbon stocks. While there has been use of parameters such as the DBH and wood density. The research was done with 22 circular plots each 1256 m2. In the 22 plots studied, 19 plots are in the gallery forest and three plots in the secondary forest. Also, 22 circular plots were distributed in 5 sites studies of Lesio-louna forest, including: Inkou forest island, Iboubikro, Ngoyili, Blue lake and Ngambali. So, there are two forest types (secondary forest and gallery forest) in this forest ecosystem. In the 5 sites studied, we made measurements on a total of 347 trees with 197 trees for the class of 10-30 cm diameter, 131 trees for the class of 30-60 cm diameter and 19 trees in the diameter class > 60 cm. The results show that in the whole forest, average carbon stock for the 22 plots of the study was 168.601 t C ha-1 for AGB, or 81% and 39.551 t C ha-1 for BGB, or 19%. The total carbon stocks in all the biomass was 3395.365 t C for AGB, which is 3.395365 × 10-6 Gt C and 909.689934 t C for BGB, which was 9.09689934 × 10-7 Gt C. In this forest, the carbon stock was more important in AGB compared to BGB with respectively 3395.365 t C against 909.689934 t C. Plot10 (AGB = 363.899 t C ha-1 and BGB = 85.516 t C ha-1) was the most dominant in terms of carbon quantification in Lesio-louna.

  17. Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe

    Science.gov (United States)

    Chen, Dima; Lan, Zhichun; Bai, Xue; Grace, James B.; Bai, Yongfei

    2013-01-01

    Anthropogenic acid deposition–induced soil acidification is one of the major threats to biodiversity, ecosystem functioning and services. Few studies, however, have explored in detail how above-ground changes in plant species richness and productivity resulting from soil acidification are mediated by effects on below-ground biota and soil properties.

  18. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  19. Regulation of abiotic and biotic stress responses by plant hormones

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2016-01-01

    Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

  20. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

    Science.gov (United States)

    Aratchige, N S; Lesna, I; Sabelis, M W

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

  1. How to integrate geology, biology, and modern wireless technologies to assess biotic-abiotic interactions on coastal dune systems: a new multidisciplinary approach

    Science.gov (United States)

    Sarti, Giovanni; Bertoni, Duccio; Bini, Monica; Ciccarelli, Daniela; Ribolini, Adriano; Ruocco, Matteo; Pozzebon, Alessandro; Alquini, Fernanda; Giaccari, Riccardo; Tordella, Stefano

    2014-05-01

    Coastal dune systems are arguably one of the most dynamic environments because their evolution is controlled by many factors, both natural and human-related. Hence, they are often exposed to processes leading to erosion, which in turn determine serious naturalistic and economic losses. Most recent studies carried out on different dune fields worldwide emphasized the notion that a better definition of this environment needs an approach that systematically involves several disciplines, striving to merge every data collected from any individual analyses. Therefore, a new multidisciplinary method to study coastal dune systems has been conceived in order to integrate geology, biology, and modern wireless technologies. The aim of the work is threefold: i) to check the reliability of this new approach; ii) to provide a dataset as complete as ever about the factors affecting the evolution of coastal dunes; and iii) to evaluate the influence of any biotic and abiotic factors on plant communities. The experimentation site is located along the Pisa coast within the Migliarino - S. Rossore - Massaciuccoli Regional Park, a protected area where human influence is low (Tuscany, Italy). A rectangle of 100 x 200 m containing 50 grids of 20 x 20 m was established along the coastal dune systems from the coastline to the pinewood at the landward end of the backdune area. Sampling from each grid determined grain-size analysis carried out on surface sediment samples such as geologic aspects; topographic surveys performed by means of DGPS-RTK instruments; geophysical surveys conducted with a GPR equipment, which will be matched with core drilling activities; digital image analysis of high definition pictures taken by means of a remote controlled aircraft drone flying over the study area; biological data obtained by percent cover of each vascular plant species recorded in the sampling unit. Along with geologic and biologic methodologies, this research implemented the use of informatics

  2. Biotic and abiotic factors investigated in two Drosophila species – evidence of both negative and positive effects of interactions on performance

    DEFF Research Database (Denmark)

    Ørsted, Michael; Schou, Mads Fristrup; Kristensen, Torsten Nygaard

    2017-01-01

    Multiple environmental factors acting in concert can interact and strongly influence population fitness and ecosystem composition. Studies investigating interactions usually involve only two environmental factors; most frequently a chemical and another abiotic factor such as a stressful temperature....... Here we investigate the effects of three environmental factors: temperature, an insecticide (dimethoate) and interspecific co-occurrence. We expose two naturally co-occurring species of Drosophila (D. hydei and D. melanogaster) to the different environments during development and examine...... the consequences on several performance measures. Results are highly species and trait specific with evidence of two- and three-way interactions in approximately 30% of all cases, suggesting that additive effects of combined environmental factors are most common, and that interactions are not universal. To provide...

  3. Direct and indirect climatic drivers of biotic interactions: ice-cover and carbon runoff shaping Arctic char Salvelinus alpinus and brown trout Salmo trutta competitive asymmetries.

    Science.gov (United States)

    Ulvan, Eva M; Finstad, Anders G; Ugedal, Ola; Berg, Ole Kristian

    2012-01-01

    One of the major challenges in ecological climate change impact science is to untangle the climatic effects on biological interactions and indirect cascading effects through different ecosystems. Here, we test for direct and indirect climatic drivers on competitive impact of Arctic char (Salvelinus alpinus L.) on brown trout (Salmo trutta L.) along a climate gradient in central Scandinavia, spanning from coastal to high-alpine environments. As a measure of competitive impact, trout food consumption was measured using (137)Cs tracer methodology both during the ice-covered and ice-free periods, and contrasted between lakes with or without char coexistence along the climate gradient. Variation in food consumption between lakes was best described by a linear mixed effect model including a three-way interaction between the presence/absence of Arctic char, season and Secchi depth. The latter is proxy for terrestrial dissolved organic carbon run-off, strongly governed by climatic properties of the catchment. The presence of Arctic char had a negative impact on trout food consumption. However, this effect was stronger during ice-cover and in lakes receiving high carbon load from the catchment, whereas no effect of water temperature was evident. In conclusion, the length of the ice-covered period and the export of allochthonous material from the catchment are likely major, but contrasting, climatic drivers of the competitive interaction between two freshwater lake top predators. While future climatic scenarios predict shorter ice-cover duration, they also predict increased carbon run-off. The present study therefore emphasizes the complexity of cascading ecosystem effects in future effects of climate change on freshwater ecosystems.

  4. Above- and Below-ground Biomass, Net Ecosystem Carbon Exchange, and Soil Respiration in a Poplar Populus deltoides Bartr.) stand : Changes after 3 years of Growth under Elevated CO2

    Science.gov (United States)

    Barron-Gafford, G. A.; Grieve, K.; Bil, K.; Kudeyarov, V.; Handley, L.; Murthy, R.

    2003-12-01

    Stands of cottonwood (Populus deltoides Bartr.) trees were grown as a coppiced system under ambient (40 Pa), twice ambient (80 Pa), and three times ambient (120 Pa) partial pressure CO2 for the past three years in the Intensively-managed Forest Mesocosm (IFM) of the Biosphere 2 Center. Over three years Net Ecosystem CO2 exchange (NECE) was measured continuously and in the third year, nine whole trees were harvested from each CO2 treatment over the growing season. Both above- and below-ground parameters were measured. Three years of growth under elevated CO2 showed the expected stimulation in foliar biomass (8.7, 11.9, and 13.1 kg for the 40, 80, and 120 Pa treatments, respectively). Rates of NECE also followed an expected increase with elevated atmospheric CO2 concentrations, with maximum CO2 uptake rates reaching 10.5, 15.6, and 19.6 μ moles m-2 s-1 in the 40, 80, and 120 Pa treatments, respectively. However, above ground woody biomass and root biomass were not much stimulated beyond 80 Pa CO2. Wood/foliage and above/below ground biomass ratios reflect this decline. Under conditions of non-limiting nutrients and water, we found consistent increases in the above/below ground biomass ratio and wood to foliage biomass ratios in the 80 compared to the 40 Pa pCO2. Woody biomass production and the above/below ground biomass ratio were lower under the 120 Pa than any other treatment. Although biomass production did not change appreciably between 80 and 120 Pa CO2 treatments, both substrate induced and in-situ soil respiration values are also significantly higher in the 120Pa treatment, though no differences were present prior to CO2 treatments (Murthy et al. 2003). The unique closed-system operation of the IFM allowed for measures of soil CO2 efflux to be measured at both the soil collar and stand scales using a box model that takes into account all inputs and outputs from the stand. In-situ soil respiration rates increased significantly with increased atmospheric CO2

  5. The influence of water stress on biomass and N accumulation, N partitioning between above and below ground parts and on N rhizodeposition during reproductive growth of pea (Pisum sativum L.)

    DEFF Research Database (Denmark)

    Mahieu, S.; Germont, Florent; Aveline, A.

    2009-01-01

    rhizodeposition by a pea (Pisum sativum L.) when influenced by water stress. In a controlled environment, pea plants were exposed to a severe drought or not stressed, either at flowering or during pod filling. N rhizodeposition was measured using the split root method and plants were harvested at the end...... of flowering (59 days after sowing, DAS 59), at the end of the drought period applied during pod filling (DAS 74) and at maturity (DAS 101). Water stress strongly affected pea dry weight and N accumulation. In both stressed treatments, nodule biomass and N content were reduced by about 65% in the absence...... in rhizodeposits represented around 30% of the total BGN and increased to around 60% at maturity though BGN decreased from around 20 to 13% of the total plant N between DAS 74 and maturity. The results suggest that water stress has no specific effect on N partitioning between above and below ground parts....

  6. Environmental extremes and biotic interactions facilitate depredation of endangered California Ridgway’s rail in a San Francisco Bay tidal marsh

    Science.gov (United States)

    Overton, Cory T.; Bobzien, Steven; Grefsrud, Marcia

    2016-01-01

    On 23 December 2015 while performing a high tide population survey for endangered Ridgway’s rails (Rallus obsoletus obsoletus; formerly known as the California clapper rail) and other rail species at Arrowhead Marsh, Martin Luther King Jr. Regional Shoreline, Oakland, California, the authors observed a series of species interactions resulting in the predation of a Ridgway’s rail by an adult female peregrine falcon (Falco peregrinus). High tide surveys are performed during the highest tides of the year when tidal marsh vegetation at Arrowhead Marsh becomes inundated, concentrating the tidal marsh obligate species into the limited area of emergent vegetation remaining as refuge cover. Annual mean tide level (elevation referenced relative to mean lower low water) at Arrowhead Marsh is 1.10 m, mean higher high water is 2.04 m (NOAA National Ocean Service 2014) and the average elevation of the marsh surface is 1.60 m (Overton et al. 2014). Tidal conditions on the day of the survey were predicted to be 2.42 m. Observed tides at the nearby Alameda Island tide gauge were 8 cm higher than predicted due to a regional low-pressure system and warmer than average sea surface temperatures (NOAA National Ocean Service 2014). The approximately 80 cm deep inundation of the marsh plain was sufficient to completely submerge tidal marsh vegetation and effectively remove 90% of refugia habitats.

  7. Biotic Habitat Complexity Controls Species Diversity and Nutrient Effects on Net Biomass Production

    NARCIS (Netherlands)

    Eriksson, Britas Klemens; Rubach, Anja; Hillebrand, Helmut

    2006-01-01

    Canopy-forming plants and algae commonly contribute to spatial variation in habitat complexity for associated organisms and thereby create a biotic patchiness of communities. In this study, we tested for interaction effects between biotic habitat complexity and resource availability on net biomass

  8. Strong biotic influences on regional patterns of climate regulation services

    Science.gov (United States)

    Serna-Chavez, H. M.; Swenson, N. G.; Weiser, M. D.; van Loon, E. E.; Bouten, W.; Davidson, M. D.; van Bodegom, P. M.

    2017-05-01

    Climate regulation services from forests are an important leverage in global-change mitigation treaties. Like most ecosystem services, climate regulation is the product of various ecological phenomena with unique spatial features. Elucidating which abiotic and biotic factors relate to spatial patterns of climate regulation services advances our understanding of what underlies climate-mitigation potential and its variation within and across ecosystems. Here we quantify and contrast the statistical relations between climate regulation services (albedo and evapotranspiration, primary productivity, and soil carbon) and abiotic and biotic factors. We focus on 16,955 forest plots in a regional extent across the eastern United States. We find the statistical effects of forest litter and understory carbon on climate regulation services to be as strong as those of temperature-precipitation interactions. These biotic factors likely influence climate regulation through changes in vegetation and canopy density, radiance scattering, and decomposition rates. We also find a moderate relation between leaf nitrogen traits and primary productivity at this regional scale. The statistical relation between climate regulation and temperature-precipitation ranges, seasonality, and climatic thresholds highlights a strong feedback with global climate change. Our assessment suggests the expression of strong biotic influences on climate regulation services at a regional, temperate extent. Biotic homogenization and management practices manipulating forest structure and succession will likely strongly impact climate-mitigation potential. The identity, strength, and direction of primary influences differed for each process involved in climate regulation. Hence, different abiotic and biotic factors are needed to monitor and quantify the full climate-mitigation potential of temperate forest ecosystems.

  9. The Importance of Biotic vs. Abiotic Drivers of Local Plant Community Composition Along Regional Bioclimatic Gradients.

    Directory of Open Access Journals (Sweden)

    Kari Klanderud

    Full Text Available We assessed if the relative importance of biotic and abiotic factors for plant community composition differs along environmental gradients and between functional groups, and asked which implications this may have in a warmer and wetter future. The study location is a unique grid of sites spanning regional-scale temperature and precipitation gradients in boreal and alpine grasslands in southern Norway. Within each site we sampled vegetation and associated biotic and abiotic factors, and combined broad- and fine-scale ordination analyses to assess the relative explanatory power of these factors for species composition. Although the community responses to biotic and abiotic factors did not consistently change as predicted along the bioclimatic gradients, abiotic variables tended to explain a larger proportion of the variation in species composition towards colder sites, whereas biotic variables explained more towards warmer sites, supporting the stress gradient hypothesis. Significant interactions with precipitation suggest that biotic variables explained more towards wetter climates in the sub alpine and boreal sites, but more towards drier climates in the colder alpine. Thus, we predict that biotic interactions may become more important in alpine and boreal grasslands in a warmer future, although more winter precipitation may counteract this trend in oceanic alpine climates. Our results show that both local and regional scales analyses are needed to disentangle the local vegetation-environment relationships and their regional-scale drivers, and biotic interactions and precipitation must be included when predicting future species assemblages.

  10. Biotic elements of NPP techno-ecosystem

    International Nuclear Information System (INIS)

    Protasov, A.A.; Silaeva, A.A.

    2013-01-01

    Specific features of biotic elements in the NPP techno-ecosystems were considered and compared with natural ecosystems. Relationships between biotic communities and environmental factors that are specific to the techno-ecosystems were discussed, and the problems of limitation of biological hindrances in operation of equipment, principles of hydrobiological and environmental monitoring were considered.

  11. Biotic Proxies For Ocean Acidification?

    Science.gov (United States)

    Thomas, E.

    2013-12-01

    Present and future high atmospheric pCO2 levels have caused acidification of the oceans, which has led to studies of past ocean acidification and its biotic response in the geological record (1). Therefore we need proxies for past acidification. Geochemical proxies for ocean pH are being developed (e.g., boron based), and various trace element and stable isotope proxies in part reflect carbonate saturation levels. In addition to geochemical proxies, the relative abundances of some benthic foraminiferal species might serve as proxies for the saturation state of bottom or pore waters. In general, pore waters are less carbonate-saturated than bottom waters, and infaunal benthic foraminifera calcify in such less saturated waters. The relative abundance of infaunal species of benthic foraminifera has commonly been used as a proxy for a high food supply (and/or oxygen depleted bottom or pore waters). This proxy (infaunal %), however, can be used to indicate high food/low oxygen ONLY in the absence of evidence for carbonate dissolution, and is a qualitative proxy for carbonate undersaturation of bottom and pore waters in the presence of such evidence (2). The living species Nuttallides umbonifer can calcify in carbonate-corrosive waters (i.e., below the lysocline), and its extinct Paleogene ancestor N. truempyi may have had a similar tolerance, in view of the fact that it is a deep-water species and commonly abundant in samples which otherwise contain agglutinant taxa only. The pattern of deep-sea benthic foraminiferal abundances across the Paleocene Eocene Thermal Maximum at South Atlantic Site 1263 (Walvis Ridge) can then be interpreted as a time sequence indicative of full dissolution (no calcareous benthics) at the start of the event, followed by strong dissolution (mainly infaunal taxa with relatively high % of N. truempyi), moderate dissolution (high % of N. truempyi), and return to background conditions. On the opposite extreme, extinction of pelagic calcifiers at

  12. Local biotic adaptation of trees and shrubs to plant neighbors

    Science.gov (United States)

    Grady, Kevin C.; Wood, Troy E.; Kolb, Thomas E.; Hersch-Green, Erika; Shuster, Stephen M.; Gehring, Catherine A.; Hart, Stephen C.; Allan, Gerard J.; Whitham, Thomas G.

    2017-01-01

    Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con- or hetero-specific sympatric neighbor genotypes with a shared site-level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontiiand S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant-community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co-evolution among herbaceous taxa, and

  13. The Natural Biotic Environment of Caenorhabditis elegans

    Science.gov (United States)

    Schulenburg, Hinrich; Félix, Marie-Anne

    2017-01-01

    Organisms evolve in response to their natural environment. Consideration of natural ecological parameters are thus of key importance for our understanding of an organism’s biology. Curiously, the natural ecology of the model species Caenorhabditis elegans has long been neglected, even though this nematode has become one of the most intensively studied models in biological research. This lack of interest changed ∼10 yr ago. Since then, an increasing number of studies have focused on the nematode’s natural ecology. Yet many unknowns still remain. Here, we provide an overview of the currently available information on the natural environment of C. elegans. We focus on the biotic environment, which is usually less predictable and thus can create high selective constraints that are likely to have had a strong impact on C. elegans evolution. This nematode is particularly abundant in microbe-rich environments, especially rotting plant matter such as decomposing fruits and stems. In this environment, it is part of a complex interaction network, which is particularly shaped by a species-rich microbial community. These microbes can be food, part of a beneficial gut microbiome, parasites and pathogens, and possibly competitors. C. elegans is additionally confronted with predators; it interacts with vector organisms that facilitate dispersal to new habitats, and also with competitors for similar food environments, including competitors from congeneric and also the same species. Full appreciation of this nematode’s biology warrants further exploration of its natural environment and subsequent integration of this information into the well-established laboratory-based research approaches. PMID:28476862

  14. Biotic replacement and mass extinction of the Ediacara biota.

    Science.gov (United States)

    Darroch, Simon A F; Sperling, Erik A; Boag, Thomas H; Racicot, Rachel A; Mason, Sara J; Morgan, Alex S; Tweedt, Sarah; Myrow, Paul; Johnston, David T; Erwin, Douglas H; Laflamme, Marc

    2015-09-07

    The latest Neoproterozoic extinction of the Ediacara biota has been variously attributed to catastrophic removal by perturbations to global geochemical cycles, 'biotic replacement' by Cambrian-type ecosystem engineers, and a taphonomic artefact. We perform the first critical test of the 'biotic replacement' hypothesis using combined palaeoecological and geochemical data collected from the youngest Ediacaran strata in southern Namibia. We find that, even after accounting for a variety of potential sampling and taphonomic biases, the Ediacaran assemblage preserved at Farm Swartpunt has significantly lower genus richness than older assemblages. Geochemical and sedimentological analyses confirm an oxygenated and non-restricted palaeoenvironment for fossil-bearing sediments, thus suggesting that oxygen stress and/or hypersalinity are unlikely to be responsible for the low diversity of communities preserved at Swartpunt. These combined analyses suggest depauperate communities characterized the latest Ediacaran and provide the first quantitative support for the biotic replacement model for the end of the Ediacara biota. Although more sites (especially those recording different palaeoenvironments) are undoubtedly needed, this study provides the first quantitative palaeoecological evidence to suggest that evolutionary innovation, ecosystem engineering and biological interactions may have ultimately caused the first mass extinction of complex life. © 2015 The Author(s).

  15. Coevolutionary aesthetics in human and biotic artworlds.

    Science.gov (United States)

    Prum, Richard O

    2013-01-01

    This work proposes a coevolutionary theory of aesthetics that encompasses both biotic and human arts. Anthropocentric perspectives in aesthetics prevent the recognition of the ontological complexity of the aesthetics of nature, and the aesthetic agency of many non-human organisms. The process of evaluative coevolution is shared by all biotic advertisements. I propose that art consists of a form of communication that coevolves with its own evaluation. Art and art history are population phenomena. I expand Arthur Danto's Artworld concept to any aesthetic population of producers and evaluators. Current concepts of art cannot exclusively circumscribe the human arts from many forms of non-human biotic art. Without assuming an arbitrarily anthropocentric perspective, any concept of art will need to engage with biodiversity, and either recognize many instances of biotic advertisements as art, or exclude some instances of human art. Coevolutionary aesthetic theory provides a heuristic account of aesthetic change in both human and biotic artworlds, including the coevolutionary origin of aesthetic properties and aesthetic value within artworlds. Restructuring aesthetics, art criticism, and art history without human beings at the organizing centers of these disciplines stimulate new progress in our understanding of art, and the unique human contributions to aesthetics and aesthetic diversity.

  16. The influence of environmental, biotic and spatial factors on diatom metacommunity structure in Swedish headwater streams.

    Directory of Open Access Journals (Sweden)

    Emma Göthe

    Full Text Available Stream assemblages are structured by a combination of local (environmental filtering and biotic interactions and regional factors (e.g., dispersal related processes. The relative importance of environmental and spatial (i.e., regional factors structuring stream assemblages has been frequently assessed in previous large-scale studies, but biotic predictors (potentially reflecting local biotic interactions have rarely been included. Diatoms may be useful for studying the effect of trophic interactions on community structure since: (1 a majority of experimental studies shows significant grazing effects on diatom species composition, and (2 assemblages can be divided into guilds that have different susceptibility to grazing. We used a dataset from boreal headwater streams in south-central Sweden (covering a spatial extent of ∼14000 km(2, which included information about diatom taxonomic composition, abundance of invertebrate grazers (biotic factor, environmental (physicochemical and spatial factors (obtained through spatial eigenfunction analyses. We assessed the relative importance of environmental, biotic, and spatial factors structuring diatom assemblages, and performed separate analyses on different diatom guilds. Our results showed that the diatom assemblages were mainly structured by environmental factors. However, unique spatial and biological gradients, specific to different guilds and unrelated to each other, were also evident. We conclude that biological predictors, in combination with environmental and spatial variables, can reveal a more complete picture of the local vs. regional control of species assemblages in lotic environments. Biotic factors should therefore not be overlooked in applied research since they can capture additional local control and therefore increase accuracy and performance of predictive models. The inclusion of biotic predictors did, however, not significantly influence the unique fraction explained by spatial

  17. The Influence of Environmental, Biotic and Spatial Factors on Diatom Metacommunity Structure in Swedish Headwater Streams

    Science.gov (United States)

    Göthe, Emma; Angeler, David G.; Gottschalk, Steffi; Löfgren, Stefan; Sandin, Leonard

    2013-01-01

    Stream assemblages are structured by a combination of local (environmental filtering and biotic interactions) and regional factors (e.g., dispersal related processes). The relative importance of environmental and spatial (i.e., regional) factors structuring stream assemblages has been frequently assessed in previous large-scale studies, but biotic predictors (potentially reflecting local biotic interactions) have rarely been included. Diatoms may be useful for studying the effect of trophic interactions on community structure since: (1) a majority of experimental studies shows significant grazing effects on diatom species composition, and (2) assemblages can be divided into guilds that have different susceptibility to grazing. We used a dataset from boreal headwater streams in south-central Sweden (covering a spatial extent of ∼14000 km2), which included information about diatom taxonomic composition, abundance of invertebrate grazers (biotic factor), environmental (physicochemical) and spatial factors (obtained through spatial eigenfunction analyses). We assessed the relative importance of environmental, biotic, and spatial factors structuring diatom assemblages, and performed separate analyses on different diatom guilds. Our results showed that the diatom assemblages were mainly structured by environmental factors. However, unique spatial and biological gradients, specific to different guilds and unrelated to each other, were also evident. We conclude that biological predictors, in combination with environmental and spatial variables, can reveal a more complete picture of the local vs. regional control of species assemblages in lotic environments. Biotic factors should therefore not be overlooked in applied research since they can capture additional local control and therefore increase accuracy and performance of predictive models. The inclusion of biotic predictors did, however, not significantly influence the unique fraction explained by spatial factors

  18. Design, engineering and utility of biotic games.

    Science.gov (United States)

    Riedel-Kruse, Ingmar H; Chung, Alice M; Dura, Burak; Hamilton, Andrea L; Lee, Byung C

    2011-01-07

    Games are a significant and defining part of human culture, and their utility beyond pure entertainment has been demonstrated with so-called 'serious games'. Biotechnology--despite its recent advancements--has had no impact on gaming yet. Here we propose the concept of 'biotic games', i.e., games that operate on biological processes. Utilizing a variety of biological processes we designed and tested a collection of games: 'Enlightenment', 'Ciliaball', 'PAC-mecium', 'Microbash', 'Biotic Pinball', 'POND PONG', 'PolymerRace', and 'The Prisoner's Smellemma'. We found that biotic games exhibit unique features compared to existing game modalities, such as utilizing biological noise, providing a real-life experience rather than virtual reality, and integrating the chemical senses into play. Analogous to video games, biotic games could have significant conceptual and cost-reducing effects on biotechnology and eventually healthcare; enable volunteers to participate in crowd-sourcing to support medical research; and educate society at large to support personal medical decisions and the public discourse on bio-related issues.

  19. Polistes olivaceous decreases biotic surface colonization

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... Polistes olivaceous on oral biotic surface (biofilm) model by means of pH response, population of oral bacteria and enamel .... Another 50 subjects used oral rinses of 0.9% normal saline to serve as a negative control and ... Bacterial count of S. mutans, S. sanguis and S. salivarus in each flow. Bacteria.

  20. Interactions between Zostera capensis , Callianassa kraussi and ...

    African Journals Online (AJOL)

    Seven facts point to mutually antagonistic interactions between the species: (1) cover of Z. capensis was negatively correlated with density of C. kraussi; (2) Z. ... below eelgrass beds there was a 'frontier zone' where above-ground Z. capensis was absent but below-ground root-rhizomes appeared to exclude C. kraussi; ...

  1. Declining of forests - biotic and abiotic stress

    Directory of Open Access Journals (Sweden)

    Radulović Zlatan

    2014-01-01

    Full Text Available During the last several years, a significant decline of different forests in Serbia was recorded. The decline is more widespread in conifer stands, but occurence of decline was recorded in broadleaved forest stands as well. These declines are the result of abiotic, biotic and anthropogenic factors. According to the studies performed so far in Serbia, the predisposing factor were droughts during the 2012 and 2013 vegetation periods that caused physiological weakness of the trees. Among the biotic factors, the most important are fungi (mainly root rot, but rot fungi, and needle diseases and insects (bark beetles in conifer species and defoliators in broadleaved species. [Projekat Ministarstva nauke Republike Srbije, br. TR 37008 i br. TR 31070

  2. Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress

    Science.gov (United States)

    Here we argue for a research initiative on gene-for-gene (g-f-g) interactions between wheat and its parasites. One aim is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to biotic stress are integrated in an import...

  3. Rodent seed predation as a biotic filter influencing exotic plant abundance and distribution

    Science.gov (United States)

    D. E. Pearson; J. L. Hierro; M. Chiuffo; D. Villarreal

    2014-01-01

    Biotic resistance is commonly invoked to explain why many exotic plants fail to thrive in introduced ranges, but the role of seed predation as an invasion filter is understudied. Abiotic conditions may also influence plant populations and can interact with consumers to determine plant distributions, but how these factors jointly influence invasions is poorly understood...

  4. Biotic and abiotic variables show little redundancy in explaining tree species distributions

    DEFF Research Database (Denmark)

    Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.

    2010-01-01

    Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...

  5. Cascaded neural networks improving fish species prediction accuracy: the role of the biotic information.

    Science.gov (United States)

    Franceschini, Simone; Gandola, Emanuele; Martinoli, Marco; Tancioni, Lorenzo; Scardi, Michele

    2018-03-15

    Species distribution is the result of complex interactions that involve environmental parameters as well as biotic factors. However, methodological approaches that consider the use of biotic variables during the prediction process are still largely lacking. Here, a cascaded Artificial Neural Networks (ANN) approach is proposed in order to increase the accuracy of fish species occurrence estimates and a case study for Leucos aula in NE Italy is presented as a demonstration case. Potentially useful biotic information (i.e. occurrence of other species) was selected by means of tetrachoric correlation analysis and on the basis of the improvements it allowed to obtain relative to models based on environmental variables only. The prediction accuracy of the L. aula model based on environmental variables only was improved by the addition of occurrence data for A. arborella and S. erythrophthalmus. While biotic information was needed to train the ANNs, the final cascaded ANN model was able to predict L. aula better than a conventional ANN using environmental variables only as inputs. Results highlighted that biotic information provided by occurrence estimates for non-target species whose distribution can be more easily and accurately modeled may play a very useful role, providing additional predictive variables to target species distribution models.

  6. Plant Immune System: Crosstalk Between Responses to Biotic and Abiotic Stresses the Missing Link in Understanding Plant Defence.

    Science.gov (United States)

    Nejat, Naghmeh; Mantri, Nitin

    2017-01-01

    Environmental pollution, global warming and climate change exacerbate the impact of biotic and abiotic stresses on plant growth and yield. Plants have evolved sophisticated defence network, also called innate immune system, in response to ever- changing environmental conditions. Significant progress has been made in identifying the key stress-inducible genes associated with defence response to single stressors. However, relatively little information is available on the signaling crosstalk in response to combined biotic/abiotic stresses. Recent evidence highlights the complex nature of interactions between biotic and abiotic stress responses, significant aberrant signaling crosstalk in response to combined stresses and a degree of overlap, but unique response to each environmental stimulus. Further, the results of simultaneous combined biotic and abiotic stress studies indicate that abiotic stresses particularly heat and drought enhance plant susceptibility to plant pathogens. It is noteworthy that global climate change is predicted to have a negative impact on biotic stress resistance in plants. Therefore, it is vital to conduct plant transcriptome analysis in response to combined stresses to identify general or multiple stress- and pathogen-specific genes that confer multiple stress tolerance in plants under climate change. Here, we discuss the recent advances in our understanding of the molecular mechanisms of crosstalk in response to biotic and abiotic stresses. Pinpointing both, common and specific components of the signaling crosstalk in plants, allows identification of new targets and development of novel methods to combat biotic and abiotic stresses under global climate change.

  7. Dynamics of radon-222 near below ground surface

    International Nuclear Information System (INIS)

    Fukui, Masami; Katsurayama, Kousuke; Nishimura, Susumu.

    1986-01-01

    The concentrations and variation of 222 Rn were investigated both in unconfined groundwater and in the aerated zone to obtain information as to the behavior of Rn close to ground surface. The Rn concentrations in unconfined groundwater near the surface were depletive by the extent of about 50 % compared with that of lower part in a borehole, then the continuous extraction of groundwater causes pronounced increase of the concentration. The method, which monitors continuously the Rn concentration in such surroundings, was developed, where the unconfined groundwater extracted was injected into another borehole and sprayed gas was measured using an ionization chamber. The read-out values of this system well followed the variation of concentrations caused by the meteorological parameter, especially infiltrating water. The increase of 222 Rn concentration in the aerated zone above the water level was clearly observed following the ascendant of groundwater level caused by the infiltrating water, whereas the change of concentration in soil air just below the ground surface obeyed mainly to the wetness of soil and unconfined groundwater level rather than atmospheric pressure. (author)

  8. Otidea subterranea sp. nov.: Otidea goes below ground.

    Science.gov (United States)

    Smith, Matthew E; Healy, Rosanne A

    2009-08-01

    Evidence suggests that truffle-like sporocarp forms have evolved many times in the Pezizales, but primarily from epigeous ancestors within ectomycorrhizal clades. There are several ectomycorrhizal clades, however, that contain no known hypogeous species. We collected specimens of an unusual unidentified truffle from mixed oak woodlands in Iowa. Although clearly a member of the Pezizales (Ascomycota), this hypogeous species did not belong to any of the described truffle genera. Based on a combination of ecological, phylogenetic, and morphological evidence we determined that this new truffle is a hypogeous member of the genus Otidea (Pyronemataceae), a lineage with no described truffle species. We describe it here as a new species, Otidea subterranea.

  9. Plant defense below ground and spatiotemporal processes in natural vegetation

    NARCIS (Netherlands)

    Van der Putten, W.H.

    2003-01-01

    Root herbivores and pathogens play an important role in driving plant abundance, species diversity, and succession in natural vegetation. Subterranean plant feeders and pathogenic microorganisms interfere with basic functions of plant roots, such as resource uptake, storage of reserves, and

  10. The abiotic and biotic factors limiting establishment of predatory fishes at their expanding northern range boundaries in Ontario, Canada.

    Science.gov (United States)

    Alofs, Karen M; Jackson, Donald A

    2015-06-01

    There is a poor understanding of the importance of biotic interactions in determining species distributions with climate change. Theory from invasion biology suggests that the success of species introductions outside of their historical ranges may be either positively (biotic acceptance) or negatively (biotic resistance) related to native biodiversity. Using data on fish community composition from two survey periods separated by approximately 28 years during which climate was warming, we examined the factors influencing the establishment of three predatory centrarchids: Smallmouth Bass (Micropterus dolomieu), Largemouth Bass (M. salmoides), and Rock Bass (Ambloplites rupestris) in lakes at their expanding northern range boundaries in Ontario. Variance partitioning demonstrated that, at a regional scale, abiotic factors play a stronger role in determining the establishment of these species than biotic factors. Pairing lakes within watersheds where each species had established with lakes sharing similar abiotic conditions where the species had not established revealed both positive and negative relationships between the establishment of centrarchids and the historical presence of other predatory species. The establishment of these species near their northern range boundaries is primarily determined by abiotic factors at a regional scale; however, biotic factors become important at the lake-to-lake scale. Studies of exotic species invasions have previously highlighted how spatial scale mediates the importance of abiotic vs. biotic factors on species establishment. Our study demonstrates how concepts from invasion biology can inform our understanding of the factors controlling species distributions with changing climate. © 2014 John Wiley & Sons Ltd.

  11. Methyl salicylate production in tomato affects biotic interactions

    NARCIS (Netherlands)

    Ament, K.; Krasikov, V.; Allmann, S.; Rep, M.; Takken, F.L.W.; Schuurink, R.C.

    2010-01-01

    The role of methyl salicylate (MeSA) production was studied in indirect and direct defence responses of tomato (Solanum lycopersicum) to the spider mite Tetranychus urticae and the root-invading fungus Fusarium oxysporum f. sp. lycopersici, respectively. To this end, we silenced the tomato gene

  12. ABC transporters from Botrytis cinerea in biotic and abiotic interactions

    NARCIS (Netherlands)

    Schoonbeek, H.

    2004-01-01

    Botrytis cinereais the causal agent of grey mould disease on a wide variety of crop plants. It is relatively insensitive to natural and synthetic fungitoxic compounds. This thesis describes how ABC (ATP-binding cassette) transporters contribute to protection by actively

  13. Methods for evaluating stream, riparian, and biotic conditions

    Science.gov (United States)

    William S. Platts; Walter F. Megahan; G. Wayne Minshall

    1983-01-01

    This report develops a standard way of measuring stream, riparian, and biotic conditions and evaluates the validity of the measurements recommended. Accuracy and precision of most measurements are defined. This report will be of value to those persons documenting, monitoring, or predicting stream conditions and their biotic resources, especially those related to...

  14. Physico-chemical and biotic factors influencing microalgal seed ...

    African Journals Online (AJOL)

    The growth of Chlorella vulgaris in open pond aquatic conditions poses serious challenges due to the interplay of both physico-chemical and biotic factors. We report here the monitoring of physico-chemical and biotic parameters affecting the propagation of C. vulgaris seed culture for inoculation of a large scale raceway ...

  15. End-Triassic nonmarine biotic events

    Directory of Open Access Journals (Sweden)

    Spencer G. Lucas

    2015-10-01

    Full Text Available The Late Triassic was a prolonged interval of elevated extinction rates and low origination rates that manifested themselves in a series of extinctions during Carnian, Norian and Rhaetian time. Most of these extinctions took place in the marine realm, particularly affecting radiolarians, conodonts, bivalves, ammonoids and reef-building organisms. On land, the case for a Late Triassic mass extinction is much more tenuous and has largely focused on tetrapod vertebrates (amphibians and reptiles, though some workers advocate a sudden end-Triassic (TJB extinction of land plants. Nevertheless, an extensive literature does not identify a major extinction of land plants at the TJB, and a comprehensive review of palynological records concluded that TJB vegetation changes were non-uniform (different changes in different places, not synchronous and not indicative of a mass extinction of land plants. Claims of a substantial perturbation of plant ecology and diversity at the TJB in East Greenland are indicative of a local change in the paleoflora largely driven by lithofacies changes resulting in changing taphonomic filters. Plant extinctions at the TJB were palaeogeographically localized events, not global in extent. With new and more detailed stratigraphic data, the perceived TJB tetrapod extinction is mostly an artifact of coarse temporal resolution, the compiled correlation effect. The amphibian, archosaur and synapsid extinctions of the Late Triassic are not concentrated at the TJB, but instead occur stepwise, beginning in the Norian and extending into the Hettangian. There was a disruption of the terrestrial ecosystem across the TJB, but it was more modest than generally claimed. The ecological severity of the end-Triassic nonmarine biotic events are relatively low on the global scale. Biotic turnover at the end of the Triassic was likely driven by the CAMP (Central Atlantic Magmatic Province eruptions, which caused significant environmental

  16. Invasion by nonnative brook trout in Panther Creek, Idaho: Roles of habitat quality, connectivity, and biotic resistance

    Science.gov (United States)

    Joseph R. Benjamin

    2006-01-01

    Theoretical models suggest the invasion of nonnative freshwater species is facilitated through the interaction of three factors: biotic resistance, habitat quality, and connectivity. We measured variables that represented each component to determine which were associated with small (150 mm) brook trout occurrence in Panther Creek, a tributary...

  17. Transcriptomic responses to biotic stresses in Malus x domestica: a meta-analysis study.

    Science.gov (United States)

    Balan, Bipin; Marra, Francesco Paolo; Caruso, Tiziano; Martinelli, Federico

    2018-01-31

    RNA-Seq analysis is a strong tool to gain insight into the molecular responses to biotic stresses in plants. The objective of this work is to identify specific and common molecular responses between different transcriptomic data related to fungi, virus and bacteria attacks in Malus x domestica. We analyzed seven transcriptomic datasets in Malus x domestica divided in responses to fungal pathogens, virus (Apple Stem Grooving Virus) and bacteria (Erwinia amylovora). Data were dissected using an integrated approach of pathway- and gene- set enrichment analysis, Mapman visualization tool, gene ontology analysis and inferred protein-protein interaction network. Our meta-analysis revealed that the bacterial infection enhanced specifically genes involved in sugar alcohol metabolism. Brassinosteroids were upregulated by fungal pathogens while ethylene was highly affected by Erwinia amylovora. Gibberellins and jasmonates were strongly repressed by fungal and viral infections. The protein-protein interaction network highlighted the role of WRKYs in responses to the studied pathogens. In summary, our meta-analysis provides a better understanding of the Malus X domestica transcriptome responses to different biotic stress conditions; we anticipate that these insights will assist in the development of genetic resistance and acute therapeutic strategies. This work would be an example for next meta-analysis works aiming at identifying specific common molecular features linked with biotic stress responses in other specialty crops.

  18. Biotic Invasions: Causes, Epidemiology, Global Consequences and Control

    Science.gov (United States)

    The module provides a link to an article in a series of articles in Issues in Ecology. This article presents information on biotic invaders, their destruction, controlling their detriment and the effects aquaculture is having on world fish supplies.

  19. Effect of biotic and abiotic factors on composition and foraging ...

    African Journals Online (AJOL)

    user

    scale are well known: climate, soil type, land use management practices and landscape structure are among the most influential factors (Dauber et al., 2003, 2005). At smaller scales, however, there is less agreement about the biotic and abiotic ...

  20. The Role of Silicon under Biotic and Abiotic Stress Conditions

    OpenAIRE

    YAVAŞ, İlkay; ÜNAY, Aydın

    2017-01-01

    Biotic and abiotic stress factors can adversely affect the agricultural productivity leading to physiological and biochemical damage to crops. Therefore, the most effective way is to increase the resistance to stresses. Silicon plays a role in reducing the effects of abiotic and biotic stresses (drought, salt stress, disease and insect stress etc.) on plants. Silicon is accumulated in the cell walls and intercellular spaces and thus it has beneficial effects on disease infestations in especia...

  1. Biotic and Biogeochemical Feedbacks to Climate Change

    Science.gov (United States)

    Torn, M. S.; Harte, J.

    2002-12-01

    Feedbacks to paleoclimate change are evident in ice core records showing correlations of temperature with carbon dioxide, nitrous oxide, and methane. Such feedbacks may be explained by plant and microbial responses to climate change, and are likely to occur under impending climate warming, as evidenced by results of ecosystem climate manipulation experiments and biometeorological observations along ecological and climate gradients. Ecosystems exert considerable influence on climate, by controlling the energy and water balance of the land surface as well as being sinks and sources of greenhouse gases. This presentation will focus on biotic and biogeochemical climate feedbacks on decadal to century time scales, emphasizing carbon storage and energy exchange. In addition to the direct effects of climate on decomposition rates and of climate and CO2 on plant productivity, climate change can alter species composition; because plant species differ in their surface properties, productivity, phenology, and chemistry, climate-induced changes in plant species composition can exert a large influence on the magnitude and sign of climate feedbacks. We discuss the effects of plant species on ecosystem carbon storage that result from characteristic differences in plant biomass and lifetime, allocation to roots vs. leaves, litter quality, microclimate for decomposition and the ultimate stabilization of soil organic matter. We compare the effect of species transitions on transpiration, albedo, and other surface properties, with the effect of elevated CO2 and warming on single species' surface exchange. Global change models and experiments that investigate the effect of climate only on existing vegetation may miss the biggest impacts of climate change on biogeochemical cycling and feedbacks. Quantification of feedbacks will require understanding how species composition and long-term soil processes will change under global warming. Although no single approach, be it experimental

  2. Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage

    International Nuclear Information System (INIS)

    Vollenweider, P.; Guenthardt-Goerg, Madeleine S.

    2005-01-01

    Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors. - The morphology and distribution of visible stress symptoms in tree foliage provides diagnostic tools to identify plant defense responses and differentiate stress from natural senescence symptoms

  3. Induced Systemic Tolerance to Multiple Stresses Including Biotic and Abiotic Factors by Rhizobacteria

    Directory of Open Access Journals (Sweden)

    Sung-Je Yoo

    2017-06-01

    Full Text Available Recently, global warming and drastic climate change are the greatest threat to the world. The climate change can affect plant productivity by reducing plant adaptation to diverse environments including frequent high temperature; worsen drought condition and increased pathogen transmission and infection. Plants have to survive in this condition with a variety of biotic (pathogen/pest attack and abiotic stress (salt, high/low temperature, drought. Plants can interact with beneficial microbes including plant growth-promoting rhizobacteria, which help plant mitigate biotic and abiotic stress. This overview presents that rhizobacteria plays an important role in induced systemic resistance (ISR to biotic stress or induced systemic tolerance (IST to abiotic stress condition; bacterial determinants related to ISR and/or IST. In addition, we describe effects of rhizobacteria on defense/tolerance related signal pathway in plants. We also review recent information including plant resistance or tolerance against multiple stresses (bioticabiotic. We desire that this review contribute to expand understanding and knowledge on the microbial application in a constantly varying agroecosystem, and suggest beneficial microbes as one of alternative environment-friendly application to alleviate multiple stresses.

  4. Investigation on some biotic factors in carp fish ponds

    Directory of Open Access Journals (Sweden)

    D. Terziyski

    2016-03-01

    Full Text Available Abstract. Three years studies (2004 – 2006 on the main biotic parameters (chlorophyll-a, phytoplankton biomass, zooplankton biomass and bacterioplankton biomass in carp fish ponds were carried out. The aim of the study was to investigate the biotic factors and the effect of manuring on the fish ponds. The relative -1 changes in these factors in case of fertilization with manure 3000 kg.ha or without fertilization were determined. The impact of fertilization as bottom-up melioration on some biotic factors was proven by means of paired non-parametric Wilcoxon test with following significant differences: higher levels of chlorophyll-a and higher phytoplankton biomass in fertilized ponds. Zooplankton biomass was higher in fertilized ponds, but the differences were statistically insignificant. Bacterioplankton biomass was higher in the fertilized ponds, which is an indication that the applied melioration does not lead to overload of organic matter in the ponds.

  5. Modeling invasive alien plant species in river systems: Interaction with native ecosystem engineers and effects on hydro-morphodynamic processes

    Science.gov (United States)

    van Oorschot, M.; Kleinhans, M. G.; Geerling, G. W.; Egger, G.; Leuven, R. S. E. W.; Middelkoop, H.

    2017-08-01

    Invasive alien plant species negatively impact native plant communities by out-competing species or changing abiotic and biotic conditions in their introduced range. River systems are especially vulnerable to biological invasions, because waterways can function as invasion corridors. Understanding interactions of invasive and native species and their combined effects on river dynamics is essential for developing cost-effective management strategies. However, numerical models for simulating long-term effects of these processes are lacking. This paper investigates how an invasive alien plant species affects native riparian vegetation and hydro-morphodynamics. A morphodynamic model has been coupled to a dynamic vegetation model that predicts establishment, growth and mortality of riparian trees. We introduced an invasive alien species with life-history traits based on Japanese Knotweed (Fallopia japonica), and investigated effects of low- and high propagule pressure on invasion speed, native vegetation and hydro-morphodynamic processes. Results show that high propagule pressure leads to a decline in native species cover due to competition and the creation of unfavorable native colonization sites. With low propagule pressure the invader facilitates native seedling survival by creating favorable hydro-morphodynamic conditions at colonization sites. With high invader abundance, water levels are raised and sediment transport is reduced during the growing season. In winter, when the above-ground invader biomass is gone, results are reversed and the floodplain is more prone to erosion. Invasion effects thus depend on seasonal above- and below ground dynamic vegetation properties and persistence of the invader, on the characteristics of native species it replaces, and the combined interactions with hydro-morphodynamics.

  6. Investigation of road salts and biotic stressors on freshwater wetland communities.

    Science.gov (United States)

    Jones, Devin K; Mattes, Brian M; Hintz, William D; Schuler, Matthew S; Stoler, Aaron B; Lind, Lovisa A; Cooper, Reilly O; Relyea, Rick A

    2017-02-01

    The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl 2 ), at three environmentally relevant concentrations (150, 470, and 780 mg Cl - /L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Biological interactions in the Sea

    Indian Academy of Sciences (India)

    ddattesh

    Determinants of population abundance. Microhydrodynamic, behavioral & substrate availability process. Larval pool. Physical & larval transport processes. Local biotic interactions. & disturbance. Space. Scale of processes influencing the population. Population abundance. Time. Relative importance of density dependent ...

  8. Geographic, environmental and biotic sources of variation in the nutrient relations of tropical montane forests

    Science.gov (United States)

    James W. Dalling; Katherine Heineman; Grizelle Gonzalez; Rebecca Ostertag

    2016-01-01

    Tropicalmontane forests (TMF) are associated with a widely observed suite of characteristics encompassing forest structure, plant traits and biogeochemistry.With respect to nutrient relations, montane forests are characterized by slow decomposition of organic matter, high investment in below-ground biomass and poor litter quality, relative to tropical lowland forests....

  9. Biotic diversity interfaces with urbanization in the Lake Tahoe basin

    Science.gov (United States)

    Patricia N. Manley; Dennis D. Murphy; Lori A. Campbell; Kirsten E. Heckmann; Susan Merideth; Sean A. Parks; Monte P. Sanford; Matthew D. Schlesinger

    2006-01-01

    In the Lake Tahoe Basin, the retention of native ecosystems within urban areas may greatly enhance the landscape’s ability to maintain biotic diversity. Our study of plant, invertebrate and vertebrate species showed that many native species were present in remnant forest stands in developed areas; however, their richness and abundance declined in association with...

  10. Biotic modifiers, environmental modulation and species distribution models

    NARCIS (Netherlands)

    Linder, H. Peter; Bykova, Olga; Dyke, James; Etienne, Rampal S.; Hickler, Thomas; Kuehn, Ingolf; Marion, Glenn; Ohlemueller, Ralf; Schymanski, Stanislaus J.; Singer, Alexander

    2012-01-01

    The ability of species to modulate environmental conditions and resources has long been of interest. In the past three decades the impacts of these biotic modifiers have been investigated as ecosystem engineers, niche constructors, facilitators and keystone species. This environmental modulation can

  11. Strong biotic influences on regional patterns of climate regulation services

    NARCIS (Netherlands)

    Serna-Chavez, H.M.; Swenson, N.G.; Weiser, M.D.; van Loon, E.E.; Bouten, W.; Davidson, M.D.; van Bodegom, P.M.

    2017-01-01

    Climate regulation services from forests are an important leverage in global-change mitigation treaties. Like most ecosystem services, climate regulation is the product of various ecological phenomena with unique spatial features. Elucidating which abiotic and biotic factors relate to spatial

  12. Plant Hormesis Management with Biostimulants of Biotic Origin in Agriculture

    Directory of Open Access Journals (Sweden)

    Marcela Vargas-Hernandez

    2017-10-01

    Full Text Available Over time plants developed complex mechanisms in order to adapt themselves to the environment. Plant innate immunity is one of the most important mechanisms for the environmental adaptation. A myriad of secondary metabolites with nutraceutical features are produced by the plant immune system in order to get adaptation to new environments that provoke stress (stressors. Hormesis is a phenomenon by which a stressor (i.e., toxins, herbicides, etc. stimulates the cellular stress response, including secondary metabolites production, in order to help organisms to establish adaptive responses. Hormetins of biotic origin (i.e., biostimulants or biological control compounds, in certain doses might enhance plant performance, however, in excessive doses they are commonly deleterious. Biostimulants or biological control compounds of biotic origin are called “elicitors” that have widely been studied as inducers of plant tolerance to biotic and abiotic stresses. The plant response toward elicitors is reminiscent of hormetic responses toward toxins in several organisms. Thus, controlled management of hormetic responses in plants using these types of compounds is expected to be an important tool to increase nutraceutical quality of plant food and trying to minimize negative effects on yields. The aim of this review is to analyze the potential for agriculture that the use of biostimulants and biological control compounds of biotic origin could have in the management of the plant hormesis. The use of homolog DNA as biostimulant or biological control compound in crop production is also discussed.

  13. Proteomics-based dissection of biotic stress responsive proteins in ...

    African Journals Online (AJOL)

    hope&shola

    2010-10-25

    Oct 25, 2010 ... digestion, MALDI-TOF/MS analysis and database searching of some of the identified proteins indicated that the proteins are ... identified as biotic stress responses proteins directly coupled to disease and pathogen infection on wheat. Nevertheless ... and animals (McMullen et al., 1997). Host resistance is.

  14. Ecogenomics of plant resistance to biotic and abiotic stresses

    NARCIS (Netherlands)

    Davila Olivas, N.H.

    2016-01-01

    Summary

    In natural and agricultural ecosystems, plants are exposed to a wide diversity of abiotic and biotic stresses such as drought, salinity, pathogens and insect herbivores. Under natural conditions, these stresses do not occur in isolation but commonly occur simultaneously.

  15. Evaluation of habitat suitability index models for assessing biotic resources

    Science.gov (United States)

    John C. Rennie; Joseph D. Clark; James M. Sweeney

    2000-01-01

    Existing habitat suitability index (HSI) models are evaluated for assessing the biotic resources on Champion International Corporation (CIC) lands with data from a standard and an expanded timber inventory. Forty HSI models for 34 species that occur in the Southern Appalachians have been identified from the literature. All of the variables for 14 models are provided (...

  16. Does the exclusion of meiofauna affect the estimation of biotic ...

    African Journals Online (AJOL)

    Biomonitoring of rivers is usually undertaken using information based on macroinvertebrate assemblages. However, exclusion of meiofauna (i.e. invertebrates less than 0.5 mm in size) when sorting benthic invertebrates can affect the estimation of densities and other biotic indices. In the present study, the effect of excluding ...

  17. Compartment specific importance of glutathione during abiotic and biotic stress

    Directory of Open Access Journals (Sweden)

    Bernd eZechmann

    2014-10-01

    Full Text Available The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species, redox signaling, the modulation of defense gene expression and important for the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state of plants through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, Tobacco Mosaic Virus. The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g. glutathione synthesis takes place in chloroplasts and the cytosol. Thus this review will reveal the compartment specific importance of glutathione during abiotic and biotic stress conditions.

  18. Elaboration of a biotic index of pollution using macroinvertebrates ...

    African Journals Online (AJOL)

    A study on the relationships between the physicochemical parameters and of the macroinvertebrates of the Lake Nokoué was carried out for the purpose of developing a biotic index of pollution. A total of 96 stations were prospected twice during the flooding and the dry seasons from September 2004 to February 2006.

  19. Hydrolysis and biotic transformation in water in the pesticide model

    NARCIS (Netherlands)

    Horst, ter M.M.S.; Beltman, W.H.J.; Adriaanse, P.I.; Mulder, H.M.

    2017-01-01

    The TOXSWA model has been extended with the functionality to simulate hydrolysis and biotic transformation in water. TOXSWA simulates the fate of pesticides in water bodies to calculate exposure calculations for aquatic organisms or sediment-dwelling organisms as part of the aquatic risk assessment

  20. Scaled biotic disruption during early Eocene global warming events

    Directory of Open Access Journals (Sweden)

    S. J. Gibbs

    2012-11-01

    Full Text Available Late Paleocene and early Eocene hyperthermals are transient warming events associated with massive perturbations of the global carbon cycle, and are considered partial analogues for current anthropogenic climate change. Because the magnitude of carbon release varied between the events, they are natural experiments ideal for exploring the relationship between carbon cycle perturbations, climate change and biotic response. Here we quantify marine biotic variability through three million years of the early Eocene that include five hyperthermals, utilizing a method that allows us to integrate the records of different plankton groups through scenarios ranging from background to major extinction events. Our long time-series calcareous nannoplankton record indicates a scaling of biotic disruption to climate change associated with the amount of carbon released during the various hyperthermals. Critically, only the three largest hyperthermals, the Paleocene–Eocene Thermal Maximum (PETM, Eocene Thermal Maximum 2 (ETM2 and the I1 event, show above-background variance, suggesting that the magnitude of carbon input and associated climate change needs to surpass a threshold value to cause significant biotic disruption.

  1. The Real Difference between Biotic and Abiotic Methane

    Science.gov (United States)

    Cao, X.; Bao, H.; Peng, Y.

    2017-12-01

    Methane has both biotic and abiotic origins, and the identification of these two origins has important implications not only in understanding terrestrial processes but also in searching for extraterrestrial life. Carbon and hydrogen isotopes in methane have been used to identify certain biosignatures, but such efforts often suffer from ambiguity. Recent advancement in our capability in measuring multiply substituted isotopologues of methane (i.e. 13CDH3 and 12CD2H2) has found large 12CD2H2 depletion in abiotic methane. Quantum tunneling has been proposed to account for the apparent abiotic signature. However, quantum tunneling is neither unique to abiotic processes nor consistent with the observed not-so-depleted hydrogen isotope composition. Here we constructed a general kinetic model for methane formation from CO2, and validated it by fitting its parameters to observed 13CDH3, 12CD2H2, and 12CDH3. Our model revealed that the fundamental difference between biotic and abiotic methane isotopic signatures is in the source of hydrogens during methane formation. Hydrogens in biotic methane originate from the stronger carbon-hydrogen and sulfur-hydrogen bonds, while hydrogens in abiotic methane originate from the much weaker metal-hydrogen adsorption bond. This hydrogen source difference results in abiotic methane being more depleted in 12CD2H2 than the biotic one. Our model also shows that the primary kinetic hydrogen isotope effect is at approximately 0.6 for both abiotic and biotic pathways, a normal value further nullifying the role of quantum tunneling. The active and exclusive shuttling of reduced hydrogen via strong chemical bonds like carbon-hydrogen and sulfur-hydrogen in coenzymes is proposed here to be a unique signature of life. In an ironic sense, it is the equilibrated hydrogen isotope composition in the hydrogen donors that distinguishes the living from the non-living.

  2. A biotic video game smart phone kit for formal and informal biophysics education

    Science.gov (United States)

    Kim, Honesty; Lee, Seung Ah; Riedel-Kruse, Ingmar

    2015-03-01

    Novel ways for formal and informal biophysics education are important. We present a low-cost biotic game design kit that incorporates microbial organisms into an interactive gaming experience: A 3D-printable microscope containing four LEDs controlled by a joystick enable human players to provide directional light stimuli to the motile single-celled organism Euglena gracilis. These cellular behaviors are displayed on the integrated smart phone. Real time cell-tracking couples these cells into interactive biotic video game play, i.e., the human player steers Euglena to play soccer with virtual balls and goals. The player's learning curve in mastering this fun game is intrinsically coupled to develop a deeper knowledge about Euglena's cell morphology and the biophysics of its phototactic behavior. This kit is dual educational - via construction and via play - and it provides an engaging theme for a formal biophysics devices class as well as to be presented in informal outreach activities; its low cost and open soft- and hardware should enable wide adoption.

  3. The biochar effect: plant resistance to biotic stresses

    Directory of Open Access Journals (Sweden)

    YIGAL ELAD

    2012-01-01

    Full Text Available Biochar (charcoal is the solid co-product of pyrolysis, the thermal degradation of biomass in the absence of oxygen. Pyrolysis also yields gaseous and liquid biofuel products. There is a growing interest worldwide in the pyrolysis platform, for at least four reasons: (i pyrolysis can be a source of renewable biofuels; (ii many biomass waste materials can be treated by pyrolysis and thus converted into a fuel resource; (iii long-term sequestration of carbon dioxide which originated in the atmosphere may result from adding biochar to soil; and (iv biochar soil amendment contributes to improved soil fertility and crop productivity. Currently, however, very little biochar is utilized in agriculture, in part because its agronomic value in terms of crop response and soil health benefits have yet to be quantified, and because the mechanisms by which it improves soil fertility are poorly understood. The positive effects of biochar on crop productivity under conditions of extensive agriculture are frequently attributed to direct effects of biochar-supplied nutrients and to several other indirect effects, including increased water and nutrient retention, improvements in soil pH, increased soil cation exchange capacity, effects on P and S transformations and turnover, neutralization of phytotoxic compounds in the soil, improved soil physical properties, promotion of mycorrhizal fungi, and alteration of soil microbial populations and functions. Yet, the biochar effect is also evident under conditions of intensive production where many of these parameters are not limited. Biochar addition to soil alters microbial populations in the rhizosphere, albeit via mechanisms not yet understood, and may cause a shift towards beneficial microorganism populations that promote plant growth and resistance to biotic stresses. In addition to some scant evidence for biochar-induced plant protection against soilborne diseases, the induction of systemic resistance towards

  4. Enhancing crop resilience to combined abiotic and biotic stress through the dissection of physiological and molecular crosstalk

    Directory of Open Access Journals (Sweden)

    Christos eKissoudis

    2014-05-01

    Full Text Available Plants growing in their natural habitats are often challenged simultaneously by multiple stress factors, both abiotic and biotic. Research has so far been limited to responses to individual stresses, and understanding of adaptation to combinatorial stress is limited, but indicative of non-additive interactions. Omics data analysis and functional characterization of individual genes has revealed a convergence of signalling pathways for abiotic and biotic stress adaptation. Taking into account that most data originate from imposition of individual stress factors, this review summarizes these findings in a physiological context, following the pathogenesis timeline and highlighting potential differential interactions occurring between abiotic and biotic stress signalling across the different cellular compartments and at the whole plant level. Potential effects of abiotic stress on resistance components such as extracellular receptor proteins, R-genes and systemic acquired resistance will be elaborated, as well as crosstalk at the levels of hormone, ROS and redox signalling. Breeding targets and strategies are proposed focusing on either manipulation and deployment of individual common regulators such as transcription factors or pyramiding of non- (negatively interacting components such as R-genes with abiotic stress resistance genes. We propose that dissection of broad spectrum stress tolerance conferred by priming chemicals may provide an insight on stress cross regulation and additional candidate genes for improving crop performance under combined stress. Validation of the proposed strategies in lab and field experiments is a first step towards the goal of achieving tolerance to combinatorial stress in crops.

  5. Vascular plant one-zinc-finger protein 1/2 transcription factors regulate abiotic and biotic stress responses in Arabidopsis.

    Science.gov (United States)

    Nakai, Yusuke; Nakahira, Yoichi; Sumida, Hiroki; Takebayashi, Kosuke; Nagasawa, Yumiko; Yamasaki, Kanako; Akiyama, Masako; Ohme-Takagi, Masaru; Fujiwara, Sumire; Shiina, Takashi; Mitsuda, Nobutaka; Fukusaki, Eiichiro; Kubo, Yasuyuki; Sato, Masa H

    2013-03-01

    Plants adapt to abiotic and biotic stresses by activating abscisic acid-mediated (ABA) abiotic stress-responsive and salicylic acid-(SA) or jasmonic acid-mediated (JA) biotic stress-responsive pathways, respectively. Although the abiotic stress-responsive pathway interacts antagonistically with the biotic stress-responsive pathways, the mechanisms that regulate these pathways remain largely unknown. In this study, we provide insight into the function of vascular plant one-zinc-finger proteins (VOZs) that modulate various stress responses in Arabidopsis. The expression of many stress-responsive genes was changed in the voz1voz2 double mutant under normal growth conditions. Consistent with altered stress-responsive gene expression, freezing- and drought-stress tolerances were increased in the voz1voz2 double mutant. In contrast, resistance to a fungal pathogen, Colletotrichum higginsianum, and to a bacterial pathogen, Pseudomonas syringae, was severely impaired. Thus, impairing VOZ function simultaneously conferred increased abiotic tolerance and biotic stress susceptibility. In a chilling stress condition, both the VOZ1 and VOZ2 mRNA expression levels and the VOZ2 protein level gradually decreased. VOZ2 degradation during cold exposure was completely inhibited by the addition of the 26S proteasome inhibitor, MG132, a finding that suggested that VOZ2 degradation is dependent on the ubiquitin/26S proteasome system. In voz1voz2, ABA-inducible transcription factor CBF4 expression was enhanced significantly even under normal growth conditions, despite an unchanged endogenous ABA content. A finding that suggested that VOZs negatively affect CBF4 expression in an ABA-independent manner. These results suggest that VOZs function as both negative and positive regulators of the abiotic and biotic stress-responsive pathways, and control Arabidopsis adaptation to various stress conditions. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  6. Biotic resistance to exotic invasions: its role in forest ecosystems, confounding artifacts, and future directions

    Science.gov (United States)

    Gabriela C. Nunez-Mir; Andrew M. Liebhold; Qinfeng Guo; Eckehard G. Brockerhoff; Insu Jo; Kimberly Ordonez; Songlin Fei

    2017-01-01

    Biotic resistance, the ability of communities to resist exotic invasions, has long attracted interest in the research and management communities. However, inconsistencies exist in various biotic resistance studies and less is known about the current status and knowledge gaps of biotic resistance in forest ecosystems. In this paper, we provide a brief review of the...

  7. Abiotic/biotic coupling in the rhizosphere: a reactive transport modeling analysis

    Science.gov (United States)

    Lawrence, Corey R.; Steefel, Carl; Maher, Kate

    2014-01-01

    A new generation of models is needed to adequately simulate patterns of soil biogeochemical cycling in response changing global environmental drivers. For example, predicting the influence of climate change on soil organic matter storage and stability requires models capable of addressing complex biotic/abiotic interactions of rhizosphere and weathering processes. Reactive transport modeling provides a powerful framework simulating these interactions and the resulting influence on soil physical and chemical characteristics. Incorporation of organic reactions in an existing reactive transport model framework has yielded novel insights into soil weathering and development but much more work is required to adequately capture root and microbial dynamics in the rhizosphere. This endeavor provides many advantages over traditional soil biogeochemical models but also many challenges.

  8. Changes in biotic and abiotic processes following mangrove clearing

    Science.gov (United States)

    Granek, Elise; Ruttenberg, Benjamin I.

    2008-12-01

    Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an

  9. Biotic turnover rates during the Pleistocene-Holocene transition

    Science.gov (United States)

    Stivrins, Normunds; Soininen, Janne; Amon, Leeli; Fontana, Sonia L.; Gryguc, Gražyna; Heikkilä, Maija; Heiri, Oliver; Kisielienė, Dalia; Reitalu, Triin; Stančikaitė, Miglė; Veski, Siim; Seppä, Heikki

    2016-11-01

    The Northern Hemisphere is currently warming at the rate which is unprecedented during the Holocene. Quantitative palaeoclimatic records show that the most recent time in the geological history with comparable warming rates was during the Pleistocene-Holocene transition (PHT) about 14,000 to 11,000 years ago. To better understand the biotic response to rapid temperature change, we explore the community turnover rates during the PHT by focusing on the Baltic region in the southeastern sector of the Scandinavian Ice Sheet, where an exceptionally dense network on microfossil and macrofossil data that reflect the biotic community history are available. We further use a composite chironomid-based summer temperature reconstruction compiled specifically for our study region to calculate the rate of temperature change during the PHT. The fastest biotic turnover in the terrestrial and aquatic communities occurred during the Younger Dryas-Holocene shift at 11,700 years ago. This general shift in species composition was accompanied by regional extinctions, including disappearance of mammoth (Mammuthus primigenius) and reindeer (Rangifer tarandus) and many arctic-alpine plant taxa, such as Dryas octopetala, Salix polaris and Saxifraga aizoides, from the region. This rapid biotic turnover rate occurred when the rate of warming was 0.17 °C/decade, thus slightly lower than the current Northern Hemisphere warming of 0.2 °C/decade. We therefore conclude that the Younger Dryas-Holocene shift with its rapid turnover rates and associated regional extinctions represents an important palaeoanalogue to the current high latitude warming and gives insights about the probable future turnover rates and patterns of the terrestrial and aquatic ecosystem change.

  10. Invasion by non-native brook trout in Panther Creek, Idaho: Roles of habitat quality, biotic resistance, and connectivity to source habitats

    Science.gov (United States)

    Joseph R. Benjamin; Jason B. Dunham; Matthew R. Dare

    2007-01-01

    Theoretical models and empirical evidence suggest that the invasion of nonnative species in freshwaters is facilitated through the interaction of three factors: habitat quality, biotic resistance, and connectivity. We measured variables that represented each factor to determine which were associated with the occurrence of nonnative brook trout Salvelinus...

  11. Development of a new biotic index to assess freshwater pollution

    International Nuclear Information System (INIS)

    Jiang Jianguo

    2006-01-01

    We developed a new biotic index of species pollution value (SPV) and community pollution value (CPV) based on the correlation of protozoan communities with chemical water quality to assess freshwater pollution. Five hundred and twenty-three species of protozoa SPV were established based on the data of River Hangjiang and Lake Donghu. The present research was conducted in order to further consummate the biotic index. Protozoa of the water system in Changde City were collected from 16 stations using the PFU method and the water chemical parameters of the stations were analyzed. The results showed that CPV calculated from SPV had a close correlation with the degree of water pollution (p < 0.00001), which indicated that the method is reliable. By combining the data of River Hangjiang, Lake Donghu and Changde City, the final form of SPV was accomplished and the SPV list increased to 757. The ultimate water standard evaluated by CPV calculated from SPV was proposed. - A new biotic index of water quality based on protozoa is described

  12. Development of a new biotic index to assess freshwater pollution

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jianguo [College of Food and Bioengineering, South China University of Technology, Guangzhou 510640 (China)]. E-mail: jgjiang@scut.edu.cn

    2006-01-15

    We developed a new biotic index of species pollution value (SPV) and community pollution value (CPV) based on the correlation of protozoan communities with chemical water quality to assess freshwater pollution. Five hundred and twenty-three species of protozoa SPV were established based on the data of River Hangjiang and Lake Donghu. The present research was conducted in order to further consummate the biotic index. Protozoa of the water system in Changde City were collected from 16 stations using the PFU method and the water chemical parameters of the stations were analyzed. The results showed that CPV calculated from SPV had a close correlation with the degree of water pollution (p < 0.00001), which indicated that the method is reliable. By combining the data of River Hangjiang, Lake Donghu and Changde City, the final form of SPV was accomplished and the SPV list increased to 757. The ultimate water standard evaluated by CPV calculated from SPV was proposed. - A new biotic index of water quality based on protozoa is described.

  13. Interaction volatiles entre l'orge et les champignons pathogènes dans le sol

    OpenAIRE

    Fiers, Marie; Lognay, Georges; Fauconnier, Marie-Laure; Jijakli, Haissam

    2013-01-01

    Plants are able to interact with their environment by emitting volatile organic compounds. We investigated the volatile interactions that take place below ground between barley roots and two pathogenic fungi, Cochliobolus sativus and Fusarium culmorum. The volatile molecules emitted by each fungus, by non-infected barley roots and by barley roots infected with one of the fungi or the two of them were extracted by head-space solid phase micro extraction and analyzed by gas chromatography mass ...

  14. Biotic games and cloud experimentation as novel media for biophysics education

    Science.gov (United States)

    Riedel-Kruse, Ingmar; Blikstein, Paulo

    2014-03-01

    First-hand, open-ended experimentation is key for effective formal and informal biophysics education. We developed, tested and assessed multiple new platforms that enable students and children to directly interact with and learn about microscopic biophysical processes: (1) Biotic games that enable local and online play using galvano- and photo-tactic stimulation of micro-swimmers, illustrating concepts such as biased random walks, Low Reynolds number hydrodynamics, and Brownian motion; (2) an undergraduate course where students learn optics, electronics, micro-fluidics, real time image analysis, and instrument control by building biotic games; and (3) a graduate class on the biophysics of multi-cellular systems that contains a cloud experimentation lab enabling students to execute open-ended chemotaxis experiments on slimemolds online, analyze their data, and build biophysical models. Our work aims to generate the equivalent excitement and educational impact for biophysics as robotics and video games have had for mechatronics and computer science, respectively. We also discuss how scaled-up cloud experimentation systems can support MOOCs with true lab components and life-science research in general.

  15. Biotic resistance limits the invasiveness of the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), in Florida.

    Science.gov (United States)

    Funderburk, Joe; Frantz, Galen; Mellinger, Charles; Tyler-Julian, Kara; Srivastava, Mrittunjai

    2016-04-01

    The spread of the western flower thrips, Frankliniella occidentalis (Pergande), has resulted in the world-wide destabilization of established integrated pest management programs for many crops. It is hypothesized that frequent exposure to insecticides in intensive agriculture selected for resistant populations, which allowed invasive populations in the eastern USA to overcome biotic resistance from the native community of species. Research conducted in Florida to understand the role of biotic factors in limiting the abundance of the western flower thrips is reviewed. Orius spp. (Hemiptera: Anthocoridae) are effective predators that suppress populations of thrips on crop and non-crop hosts in southern and northern Florida. Orius are more effective predators of the western flower thrips than the native flower thrips, F. tritici (Fitch) and F. bispinosa (Morgan). The native species are competitors of the western flower thrips. Excessive fertilization and the use of broad-spectrum insecticides in crop fields further enhances populations of the western flower thrips. Interactions with native species clearly limit the abundance of western flower thrips in Florida, but populations are abundant in fertilized crop fields where application of insecticides excludes predators and competitor species. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  16. Abiotic and biotic controls on local spatial distribution and performance of Boechera stricta

    Directory of Open Access Journals (Sweden)

    KUSUM J NAITHANI

    2014-07-01

    Full Text Available This study investigates the relative influence of biotic and abiotic factors on community dynamics using an integrated approach and highlights the influence of space on genotypic and phenotypic traits in plant community structure. We examined the relative influence of topography, environment, spatial distance, and intra- and interspecific interactions on spatial distribution and performance of Boechera stricta (rockcress, a close perennial relative of model plant Arabidopsis. First, using Bayesian kriging, we mapped the topography and environmental gradients and explored the spatial distribution of naturally occurring rockcress plants and two neighbors, Taraxacum officinale (dandelion and Solidago missouriensis (goldenrod found in close proximity within a typical diverse meadow community across topographic and environmental gradients. We then evaluated direct and indirect relationships among variables using Mantel path analysis and developed a network displaying abiotic and biotic interactions in this community. We found significant spatial autocorrelation among rockcress individuals, either because of common microhabitats as displayed by high density of individuals at lower elevation and high soil moisture area, or limited dispersal as shown by significant spatial autocorrelation of naturally occurring inbred lines, or a combination of both. Goldenrod and dandelion density around rockcress does not show any direct relationship with rockcress fecundity, possibly due to spatial segregation of resources. However, dandelion density around rockcress shows an indirect negative influence on rockcress fecundity via herbivory, indicating interspecific competition. Overall, we suggest that common microhabitat preference and limited dispersal are the main drivers for spatial distribution. However, intra-specific interactions and insect herbivory are the main drivers of rockcress performance in the meadow community.

  17. Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination

    Czech Academy of Sciences Publication Activity Database

    Schweiger, O.; Biesmeijer, J. C.; Bommarco, R.; Hickler, T.; Hulme, P. E.; Klotz, S.; Kühn, I.; Moora, M.; Nielsen, A.; Ohlemüller, R.; Petanidou, T.; Potts, S. G.; Pyšek, Petr; Stout, J. C.; Sykes, M. T.; Tscheulin, T.; Vila, M.; Walther, G.-R.; Westphal, C.; Winter, M.; Zobel, M.; Settele, J.

    2010-01-01

    Roč. 85, č. 4 (2010), s. 777-795 ISSN 1464-7931 R&D Projects: GA MŠk 7E09053; GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * pollination * global change Subject RIV: EF - Botanics Impact factor: 6.574, year: 2010

  18. Seasonal variability in airborne biotic contaminants in swine confinement buildings.

    Directory of Open Access Journals (Sweden)

    Priyanka Kumari

    Full Text Available Little is known about the seasonal dynamics of biotic contaminants in swine confinement buildings (SCBs. The biotic contaminants of seven SCBs were monitored during one visit in the winter and one during the summer. Paired-end Illumina sequencing of the 16S rRNA gene, V3 region, was used to examine seasonal shifts in bacterial community composition and diversity. The abundances of 16S rRNA genes and six tetracycline resistance genes (tetB, tetH, tetZ, tetO, tetQ, and tetW were also quantified using real-time PCR. Bacterial abundances, community composition and diversity all showed strong seasonal patterns defined by winter peaks in abundance and diversity. Microclimatic variables of SCBs, particularly air speed, PM2.5 and total suspended particles (TSP were found significantly correlated to abundances, community composition, and diversity of bacterial bioaerosols. Seasonal fluctuations were also observed for four tetracycline resistance genes, tetH, tetO, tetQ, and tetW. The frequency of occurrences of these resistance genes were significantly higher in samples collected during winter and was also significantly correlated with air speed, PM2.5 and TSP. Overall, our results indicate that biotic contaminants in SCBs exhibit seasonal trends, and these could be associated with the microclimatic variables of SCBs. The correlations established in the current study could be helpful in establishing better management strategies to minimize the potential health impacts on both livestock and humans working in this environment.

  19. A Model of Continental Growth and Mantle Degassing Comparing Biotic and Abiotic Worlds

    Science.gov (United States)

    Höning, D.; Hansen-Goos, H.; Spohn, T.

    2012-12-01

    While examples for interaction of the biosphere with the atmosphere can be easily cited (e.g., production and consumption of O2), interaction between the biosphere and the solid planet and its interior is much less established. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. We present an interaction model that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The mantle viscosity in this model depends on the water concentration in the mantle. We use boundary layer theory of mantle convection to parameterize the mantle convection flow rate and assume that the plate speed equals the mantle flow rate. The biosphere enters the calculation through the assumption that the continental erosion rate is enhanced by a factor of several through bioactivity and through an assumed reduction of the kinetic barrier to diagenetic and metamorphic reactions (e.g., Kim et al. 2004) in the sedimentary basins in subduction zones that would lead to increased water storage capacities. We further include a stochastic model of continent-to-continent interactions that limits the effective total length of subduction zones. We use present day parameters of the Earth and explore a phase plane spanned by the percentage of surface coverage of the Earth by continents and the total water content of the mantle. We vary the ratio of the erosion rate in a postulated abiotic Earth to the present Earth, as well as the activation barrier to diagenetic and metamorphic reactions that affect the water storage capacity of the subducting crust. We find stable and unstable fixed points in

  20. Slowing global warming biotically - Options for the United States

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Each of the five biotic approaches introduced in Chapter 2 is applicable to some extent in the US. Taking US land-use characteristics into account, a menu of policy options tailored to US carbon storage opportunities is presented. Several of the options are capable of significantly reducing net US carbon emissions; several offer corollary benefits in areas other than global warming mitigation. The time frame and costs of the different options vary widely, although in most cases some level of implementation appears economically justified even without considering global warming. The approach, projected costs, and advantages of seven different policy options are profiled

  1. Biotic homogenization and differentiation of soil faunal communities in the production forest landscape: taxonomic and functional perspectives.

    Science.gov (United States)

    Mori, Akira S; Ota, Aino T; Fujii, Saori; Seino, Tatsuyuki; Kabeya, Daisuke; Okamoto, Toru; Ito, Masamichi T; Kaneko, Nobuhiro; Hasegawa, Motohiro

    2015-02-01

    Biotic homogenization has been reported worldwide. Although simplification of communities across space is often significant at larger scales, it could also occur at the local scale by changing biotic interactions. This study aimed to elucidate local community processes driving biotic homogenization of soil faunal communities, and the possibility of biotic re-differentiation. We recorded species of oribatid mites in litter and soil layers along a gradient of forest conversion from monoculture larch plantation to primary forests in central Japan. We collected data for functional traits of the recorded species to quantify functional diversity. Then we quantified their taxonomic/functional turnover. Litter diversity was reduced in the larch-dominated stands, leading to habitat homogenization. Consequently, litter communities were biologically homogenized and differentiated in the plantations and in the natural forest, respectively. Turnover of functional traits for litter communities was lower and higher than expected by chance in the plantations and in the natural stand, respectively. This result suggests that the dominant assembly process shifts from limiting similarity to habitat filtering along the forest restoration gradient. However, support for such niche-based explanations was not observed for communities in the soil layer. In the monocultures, functional diversity expected from a given regional species pool significantly decreased for litter communities but not for those in the soil layer. Such discrepancy between communities in different layers suggests that communities more exposed to anthropogenic stresses are more vulnerable to the loss of their functional roles. Our study explains possible community processes behind the observed patterns of biological organization, which can be potentially useful in guiding approaches for restoring biodiversity.

  2. Phosphate enhanced abiotic and biotic arsenic mobilization in the wetland rhizosphere.

    Science.gov (United States)

    Zhang, Zheyun; Moon, Hee Sun; Myneni, Satish C B; Jaffé, Peter R

    2017-11-01

    Although abiotic process of competitive sorption between phosphate (P) and arsenate (As(V)), especially onto iron oxides, are well understood, P-mediated biotic processes of Fe and As redox transformation contributing to As mobilization and speciation in wetlands remain poorly defined. To gain new insights into the effects of P on As mobility, speciation, and bioavailability in wetlands, well-controlled greenhouse experiments were conducted. As expected, increased P levels contributed to more As desorption, but more interestingly the interactions between P and wetland plants played a synergistic role in the microbially-mediated As mobilization and enhanced As uptake by plants. High levels of P promoted plant growth and the exudation of labile organic carbon from roots, enhancing the growth of heterotrophic bacteria, including As and Fe reducers. This in turn resulted in both, more As desorption into solution due to reductive iron dissolution, and a higher fraction of the dissolved As in the form of As(III) due to the higher number of As(V) reducers. Consistent with the dissolved As results, arsenic-XANES spectra from solid medium samples demonstrated that more As was sequestered in the rhizosphere as As(III) in the presence of high P levels than for low P levels. Hence, increased P loading to wetlands stimulates both abiotic and biotic processes in the wetland rhizosphere, resulting in more As mobilization, more As reduction, as well as more As uptake by plants. These interactions are important to be taken into account in As fate and transport models in wetlands and management of wetlands containing As. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Biotic and abiotic carbon to sulfur bond cleavage. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.W.

    1994-05-01

    The microbial desulfurization of organosulfur compounds occurs by unprecedented and largely unexplored biochemical processes. A study of such biotic desulfurizations can be expected to give rise to new and useful chemistry and enzymology. The potential value of understanding and harnessing these processes is seen in relation to the need for methods for the removal of organically bound sulfur from coal and the degradation of organic sulfur-containing pollutants. This research effort has been directed towards an examination of desulfurization ability in well characterized microorganisms, the isolation of bacteria with desulfurization ability from natural sources, the characterization and mechanistic evaluation of the observed biocatalytic processes, the development of biomimetic synthetic organic chemistry based on biotic desulfurization mechanisms and the design and preparation of improved coal model compounds for use in microbial selection processes. A systematic approach to studying biodesulfurizations was undertaken in which organosulfur compounds have been broken down into classes based on the oxidation state of the sulfur atom and the structure of the rest of the organic material. Microbes have been evaluated in terms of ability to degrade organosulfur compounds with sulfur in its sulfonic acid oxidation state. These compounds are likely intermediates in coal desulfurization and are present in the environment as persistent pollutants in the form of detergents. It is known that oxygen bonded to sulfur lowers the carbon-sulfur bond energy, providing a thermodynamic basis for starting with this class of compounds.

  4. Biotic stress: a significant contributor to organic aerosol in Europe?

    Science.gov (United States)

    Bergström, R.; Hallquist, M.; Simpson, D.; Wildt, J.; Mentel, T. F.

    2014-12-01

    We have investigated the potential impact on organic aerosol formation from biotic stress-induced emissions (SIE) of organic molecules from forests in Europe (north of lat. 45° N). Emission estimates for sesquiterpenes (SQT), methyl salicylate (MeSA) and unsaturated C17 compounds, due to different stressors, are based on experiments in the Jülich Plant Atmosphere Chamber (JPAC), combined with estimates of the fraction of stressed trees in Europe based on reported observed tree damage. SIE were introduced in the EMEP MSC-W chemical transport model and secondary organic aerosol (SOA) yields from the SIE were taken from the JPAC experiments. Based on estimates of current levels of infestation and the JPAC aerosol yields, the model results suggest that the contribution to SOA in large parts of Europe may be substantial. It is possible that SIE contributes as much, or more, to organic aerosol than the constitutive biogenic VOC emissions, at least during some periods. Based on the assumptions in this study, SIE-SOA are estimated to constitute between 50 and 70 % of the total biogenic SOA (BSOA) in a current-situation scenario where the biotic stress in northern and central European forests causes large SIE of MeSA and SQT. An alternative current-situation scenario with lower SIE, consisting solely of SQT, leads to lower SIE-SOA, between 20 and 40 % of the total BSOA. Hypothetical future scenarios with increased SIE, due to higher degrees of biotic stress, show that SOA formation due to SIE can become even larger. Unsaturated C17 BVOC (biogenic volatile organic compounds) emitted by spruce infested by the forest-honey generating bark louse, Cinara pilicornis, have a high SOA-forming potential. A model scenario investigating the effect of a regional, episodic infestation of Cinara pilicornis in Baden-Württemberg, corresponding to a year with high production of forest honey, shows that these types of events could lead to very large organic aerosol formation in the

  5. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... including puppetry and dance. However, the aesthetics of these traditions vary across cultures and carry different associative and interpretive meanings. Puppetry offers a useful frame for understanding the relationship between abstract and imitative gestures and behavior, and instantiates the complex...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...

  6. Interactions

    DEFF Research Database (Denmark)

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists such as ......The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists...... such as Lorentz and Einstein as well as mathematicians such as Poincare, Minkowski, Hilbert and Weyl contributed to this development. They created the new physical theories and the mathematical disciplines that play such paramount roles in their mathematical formulations. These physicists and mathematicians were...... also key figures in the philosophical discussions of nature and science - from philosophical tendencies like logical empiricism via critical rationalism to various neo-Kantian trends....

  7. Dissolved and labile concentrations of Cd, Cu, Pb, and Zn in the South Fork Coeur d'Alene River, Idaho: Comparisons among chemical equilibrium models and implications for biotic ligand models

    Science.gov (United States)

    Balistrieri, L.S.; Blank, R.G.

    2008-01-01

    In order to evaluate thermodynamic speciation calculations inherent in biotic ligand models, the speciation of dissolved Cd, Cu, Pb, and Zn in aquatic systems influenced by historical mining activities is examined using equilibrium computer models and the diffusive gradients in thin films (DGT) technique. Several metal/organic-matter complexation models, including WHAM VI, NICA-Donnan, and Stockholm Humic model (SHM), are used in combination with inorganic speciation models to calculate the thermodynamic speciation of dissolved metals and concentrations of metal associated with biotic ligands (e.g., fish gills). Maximum dynamic metal concentrations, determined from total dissolved metal concentrations and thermodynamic speciation calculations, are compared with labile metal concentrations measured by DGT to assess which metal/organic-matter complexation model best describes metal speciation and, thereby, biotic ligand speciation, in the studied systems. Results indicate that the choice of model that defines metal/organic-matter interactions does not affect calculated concentrations of Cd and Zn associated with biotic ligands for geochemical conditions in the study area, whereas concentrations of Cu and Pb associated with biotic ligands depend on whether the speciation calculations use WHAM VI, NICA-Donnan, or SHM. Agreement between labile metal concentrations and dynamic metal concentrations occurs when WHAM VI is used to calculate Cu speciation and SHM is used to calculate Pb speciation. Additional work in systems that contain wide ranges in concentrations of multiple metals should incorporate analytical speciation methods, such as DGT, to constrain the speciation component of biotic ligand models. ?? 2008 Elsevier Ltd.

  8. Running with the Red Queen: the role of biotic conflicts in evolution.

    Science.gov (United States)

    Brockhurst, Michael A; Chapman, Tracey; King, Kayla C; Mank, Judith E; Paterson, Steve; Hurst, Gregory D D

    2014-12-22

    What are the causes of natural selection? Over 40 years ago, Van Valen proposed the Red Queen hypothesis, which emphasized the primacy of biotic conflict over abiotic forces in driving selection. Species must continually evolve to survive in the face of their evolving enemies, yet on average their fitness remains unchanged. We define three modes of Red Queen coevolution to unify both fluctuating and directional selection within the Red Queen framework. Empirical evidence from natural interspecific antagonisms provides support for each of these modes of coevolution and suggests that they often operate simultaneously. We argue that understanding the evolutionary forces associated with interspecific interactions requires incorporation of a community framework, in which new interactions occur frequently. During their early phases, these newly established interactions are likely to drive fast evolution of both parties. We further argue that a more complete synthesis of Red Queen forces requires incorporation of the evolutionary conflicts within species that arise from sexual reproduction. Reciprocally, taking the Red Queen's perspective advances our understanding of the evolution of these intraspecific conflicts.

  9. The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms.

    Science.gov (United States)

    Mayer-Pinto, Mariana; Matias, Miguel G; Coleman, Ross A

    2016-01-01

    Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their 'susceptibility' or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems.

  10. The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms

    Directory of Open Access Journals (Sweden)

    Mariana Mayer-Pinto

    2016-05-01

    Full Text Available Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their ‘susceptibility’ or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems.

  11. The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms

    Science.gov (United States)

    Matias, Miguel G.; Coleman, Ross A.

    2016-01-01

    Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their ‘susceptibility’ or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems. PMID:27168991

  12. Views on Biotic Nature and the Idea of Sustainable Development

    Science.gov (United States)

    Łepko, Zbigniew

    2017-12-01

    The search for balance between humankind's civilisational aspirations and the durable protection of nature is conditioned by contemporaneous views of biotic nature. Of particular importance in this regard are physiocentric and physiological views that may be set against one another. The first of these was presented by Hans Jonas, the second by Lothar Schäfer. This paper does not confine itself to setting one view against the other, but rather sets minimum conditions for cooperation between their promoters in the interests of balance between the aspirations of the present generation and those of future generations. Both views of nature are in their own way conducive to a break with the illusion present in some areas of the modern natural sciences - that nature is a boundless area of are inexhaustible resources.

  13. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... including puppetry and dance. However, the aesthetics of these traditions vary across cultures and carry different associative and interpretive meanings. Puppetry offers a useful frame for understanding the relationship between abstract and imitative gestures and behavior, and instantiates the complex...

  14. Early Triassic marine biotic recovery: the predators' perspective.

    Science.gov (United States)

    Scheyer, Torsten M; Romano, Carlo; Jenks, Jim; Bucher, Hugo

    2014-01-01

    Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian) in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles) to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates) for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became apparent.

  15. Early Triassic marine biotic recovery: the predators' perspective.

    Directory of Open Access Journals (Sweden)

    Torsten M Scheyer

    Full Text Available Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became

  16. The Biotic Indexing of Water Quality and Its Application to Field Work in Schools and Colleges.

    Science.gov (United States)

    Dale, C. R.

    1980-01-01

    Discussed is the biotic indexing of water quality and its application to A-level field work with reference to the Trent Biotic Index and Chandler Score system. These indices are related to the classification of water quality used by the Department of the Environment. Interpretations and limitations of the indices are discussed. (Author/DS)

  17. The contribution of biotic and abiotic processes during azo dye reduction in anaerobic sludge

    NARCIS (Netherlands)

    Zee, van der F.P.; Bisschops, I.A.E.; Blanchard, V.G.; Bouwman, R.H.M.; Lettinga, G.; Field, J.A.

    2003-01-01

    Azo dye reduction results from a combination of biotic and abiotic processes during the anaerobic treatment of dye containing effluents. Biotic processes are due to enzymatic reactions whereas the chemical reaction is due to sulfide. In this research, the relative impact of the different azo dye

  18. A preliminary benthic macroinvertebrate index of biotic integrity (B-IBI)

    African Journals Online (AJOL)

    A Benthic Index of Biotic Integrity (B-IBI) was developed for the Moiben River. The index assesses effects of human disturbance on the biotic condition of stream macroinvertebrate communities. Eight stations were selected to represent different land-use types including forestry, settlement, grassland and mixed farming, ...

  19. Early biotic stress detection in tomato ( Solanum lycopersicum ) by BVOC emissions

    NARCIS (Netherlands)

    Kasal-Slavik, Tina; Eschweiler, Julia; Kleist, Einhard; Mumm, Roland; Goldbach, Heiner E.; Schouten, Sander; Wildt, Jürgen

    2017-01-01

    We investigated impacts of early and mild biotic stress on Biogenic Volatile Organic Compounds (BVOC) emissions from tomato in order to test their potential for early (biotic) stress detection. Tomato plants were exposed to two common fungal pathogens, Botrytis cinerea and Oidium neolycopesici and

  20. Associations between ectomycorrhizal fungi and bacterial needle endophytes in Pinus radiata: implications for biotic selection of microbial communities

    Directory of Open Access Journals (Sweden)

    Megan Arlene Rúa

    2016-03-01

    Full Text Available Studies of the ecological and evolutionary relationships between plants and their associated microbes have long been focused on single microbes, or single microbial guilds, but in reality, plants associate with a diverse array of microbes from a varied set of guilds. As such, multitrophic interactions among plant-associated microbes from multiple guilds represent an area of developing research, and can reveal how complex microbial communities are structured around plants. Interactions between coniferous plants and their associated microbes provide a good model system for such studies, as conifers host a suite of microorganisms including mutualistic ectomycorrhizal (ECM fungi and foliar bacterial endophytes. To investigate the potential role ECM fungi play in structuring foliar bacterial endophyte communities, we sampled three isolated, native populations of Monterey pine (Pinus radiata, and used constrained analysis of principal coordinates to relate the community matrices of the ECM fungi and bacterial endophytes. Our results suggest that ECM fungi may be important factors for explaining variation in bacterial endophyte communities but this effect is influenced by population and environmental characteristics, emphasizing the potential importance of other factors — biotic or abiotic — in determining the composition of bacterial communities. We also classified ECM fungi into categories based on known fungal traits associated with substrate exploration and nutrient mobilization strategies since variation in these traits allows the fungi to acquire nutrients across a wide range of abiotic conditions and may influence the outcome of multi-species interactions. Across populations and environmental factors, none of the traits associated with fungal foraging strategy types significantly structured bacterial assemblages, suggesting these ECM fungal traits are not important for understanding endophyte-ECM interactions. Overall, our results suggest

  1. Natural biotic resources in LCA: Towards an impact assessment model for sustainable supply chain management.

    Science.gov (United States)

    Crenna, Eleonora; Sozzo, Sara; Sala, Serenella

    2018-01-20

    Natural resources, biotic and abiotic, are fundamental from both the ecological and socio-economic point of view, being at the basis of life-support. However, since the demand for finite resources continues to increase, the sustainability of current production and consumption patterns is questioned both in developed and developing countries. A transition towards an economy based on biotic renewable resources (bio-economy) is considered necessary in order to support a steady provision of resources, representing an alternative to an economy based on fossil and abiotic resources. However, to ensure a sustainable use of biotic resources, there is the need of properly accounting for their use along supply chains as well as defining a robust and comprehensive impact assessment model. Since so far naturally occurring biotic resources have gained little attention in impact assessment methods, such as life cycle assessment, the aim of this study is to enable the inclusion of biotic resources in the assessment of products and supply chains. This paper puts forward a framework for biotic resources assessment, including: i) the definition of system boundaries between ecosphere and technosphere, namely between naturally occurring and man-made biotic resources; ii) a list of naturally occurring biotic resources which have a commercial value, as basis for building life cycle inventories (NOBR, e.g. wild animals, plants etc); iii) an impact pathway to identify potential impacts on both resource provision and ecosystem quality; iv) a renewability-based indicator (NOBRri) for the impact assessment of naturally occurring biotic resources, including a list of associated characterization factors. The study, building on a solid review of literature and of available statistical data, highlights and discusses the critical aspects and paradoxes related to biotic resource inclusion in LCA: from the system boundaries definition up to the resource characterization.

  2. The importance of biotic factors in predicting global change effects on decomposition of temperate forest leaf litter.

    Science.gov (United States)

    Rouifed, Soraya; Handa, I Tanya; David, Jean-François; Hättenschwiler, Stephan

    2010-05-01

    Increasing atmospheric CO(2) and temperature are predicted to alter litter decomposition via changes in litter chemistry and environmental conditions. The extent to which these predictions are influenced by biotic factors such as litter species composition or decomposer activity, and in particular how these different factors interact, is not well understood. In a 5-week laboratory experiment we compared the decomposition of leaf litter from four temperate tree species (Fagus sylvatica, Quercus petraea, Carpinus betulus and Tilia platyphyllos) in response to four interacting factors: elevated CO(2)-induced changes in litter quality, a 3 degrees C warmer environment during decomposition, changes in litter species composition, and presence/absence of a litter-feeding millipede (Glomeris marginata). Elevated CO(2) and temperature had much weaker effects on decomposition than litter species composition and the presence of Glomeris. Mass loss of elevated CO(2)-grown leaf litter was reduced in Fagus and increased in Fagus/Tilia mixtures, but was not affected in any other leaf litter treatment. Warming increased litter mass loss in Carpinus and Tilia, but not in the other two litter species and in none of the mixtures. The CO(2)- and temperature-related differences in decomposition disappeared completely when Glomeris was present. Overall, fauna activity stimulated litter mass loss, but to different degrees depending on litter species composition, with a particularly strong effect on Fagus/Tilia mixtures (+58%). Higher fauna-driven mass loss was not followed by higher C mineralization over the relatively short experimental period. Apart from a strong interaction between litter species composition and fauna, the tested factors had little or no interactive effects on decomposition. We conclude that if global change were to result in substantial shifts in plant community composition and macrofauna abundance in forest ecosystems, these interacting biotic factors could have

  3. Revisiting the Chesapeake Bay phytoplankton index of biotic integrity.

    Science.gov (United States)

    Johnson, Jacqueline M; Buchanan, Claire

    2014-03-01

    In 2006, a phytoplankton index of biotic integrity (PIBI) was published for Chesapeake Bay Lacouture et al. (Estuaries 29(4):598-616, 2006). The PIBI was developed from data collected during the first 18 years (1985-2002) of the Chesapeake Bay Program long-term phytoplankton and water quality monitoring programs. Combinations of up to nine phytoplankton metrics were selected to characterize bay habitat health according to plankton community condition in spring and summer seasons across four salinity zones. The independent data available at the time for index validation was not sufficient to test the PIBI because they lacked critical index parameters (pheophytin and dissolved organic carbon) and reference samples for some seasons and salinity zones. An additional 8 years of monitoring data (2003-2010) are now available to validate the original index, reassess index performance and re-examine long-term trends in PIBI conditions in the Bay. The PIBI remains sensitive to changes in nutrient and light conditions. Evaluation of the PIBI results over the entire 1985-2010 time period shows no discernible trends in the overall health of Bay habitat based on phytoplankton community conditions. This lack of overall PIBI trend appears to be a combined response to declines in water clarity and improvements in dissolved inorganic nitrogen and dissolved phosphorus conditions in the bay.

  4. Biotic homogenization can decrease landscape-scale forest multifunctionality

    Science.gov (United States)

    van der Plas, Fons; Manning, Pete; Soliveres, Santiago; Allan, Eric; Scherer-Lorenzen, Michael; Verheyen, Kris; Wirth, Christian; Zavala, Miguel A.; Ampoorter, Evy; Baeten, Lander; Barbaro, Luc; Bauhus, Jürgen; Benavides, Raquel; Benneter, Adam; Bonal, Damien; Bouriaud, Olivier; Bruelheide, Helge; Bussotti, Filippo; Carnol, Monique; Castagneyrol, Bastien; Charbonnier, Yohan; Coppi, Andrea; Bastias, Cristina C.; Dawud, Seid Muhie; De Wandeler, Hans; Domisch, Timo; Finér, Leena; Granier, André; Grossiord, Charlotte; Guyot, Virginie; Hättenschwiler, Stephan; Jactel, Hervé; Jaroszewicz, Bogdan; Joly, François-xavier; Jucker, Tommaso; Koricheva, Julia; Milligan, Harriet; Mueller, Sandra; Muys, Bart; Nguyen, Diem; Pollastrini, Martina; Ratcliffe, Sophia; Raulund-Rasmussen, Karsten; Selvi, Federico; Stenlid, Jan; Valladares, Fernando; Vesterdal, Lars; Zielínski, Dawid; Fischer, Markus

    2016-01-01

    Many experiments have shown that local biodiversity loss impairs the ability of ecosystems to maintain multiple ecosystem functions at high levels (multifunctionality). In contrast, the role of biodiversity in driving ecosystem multifunctionality at landscape scales remains unresolved. We used a comprehensive pan-European dataset, including 16 ecosystem functions measured in 209 forest plots across six European countries, and performed simulations to investigate how local plot-scale richness of tree species (α-diversity) and their turnover between plots (β-diversity) are related to landscape-scale multifunctionality. After accounting for variation in environmental conditions, we found that relationships between α-diversity and landscape-scale multifunctionality varied from positive to negative depending on the multifunctionality metric used. In contrast, when significant, relationships between β-diversity and landscape-scale multifunctionality were always positive, because a high spatial turnover in species composition was closely related to a high spatial turnover in functions that were supported at high levels. Our findings have major implications for forest management and indicate that biotic homogenization can have previously unrecognized and negative consequences for large-scale ecosystem multifunctionality. PMID:26979952

  5. Predators vs. alien: differential biotic resistance to an invasive species by two resident predators

    Directory of Open Access Journals (Sweden)

    Calum MacNeil

    2013-10-01

    Full Text Available The success of invading species can be restricted by interspecific interactions such as competition and predation (i.e. biotic resistance from resident species, which may be natives or previous invaders. Whilst there are myriad examples of resident species preying on invaders, simply showing that such an interaction exists does not demonstrate that predation limits invader establishment, abundance or spread. Support for this conclusion requires evidence of negative associations between invaders and resident predators in the field and, further, that the predator-prey interaction is likely to strongly regulate or potentially de-stabilise the introduced prey population. Moreover, it must be considered that different resident predator species may have different abilities to restrict invaders. In this study, we show from analysis of field data that two European predatory freshwater amphipods, Gammarus pulex and G. duebeni celticus, have strong negative field associations with their prey, the invasive North American amphipod Crangonyx pseudogracilis. This negative field association is significantly stronger with G. pulex, a previous and now resident invader in the study sites, than with the native G. d. celticus. These field patterns were consistent with our experimental findings that both resident predators display potentially population de-stabilising Type II functional responses towards the invasive prey, with a significantly greater magnitude of response exhibited by G. pulex than by G. d. celticus. Further, these Type II functional responses were consistent across homo- and heterogeneous environments, contrary to the expectation that heterogeneity facilitates more stabilising Type III functional responses through the provision of prey refugia. Our experimental approach confirms correlative field surveys and thus supports the hypothesis that resident predatory invertebrates are differentially limiting the distribution and abundance of an

  6. Tracing {sup 13}C reveals the below ground connection between trees and fungi

    Energy Technology Data Exchange (ETDEWEB)

    Siegwolf, R.T.W.; Steinmann, K.; Saurer, M.; Koerner, Ch.

    2003-03-01

    Freshly assimilated atmospheric CO{sub 2} is transferred as sugars from the leaves into the whole organism. Since mycorrhiza fungi and tree roots are in an intensive symbiosis, the fungi provide important information about the tree internal carbon distribution. (author)

  7. Hot Cell Liners Category of Transuranic Waste Stored Below Ground within Area G

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Robert Wesley [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hargis, Kenneth Marshall [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-01

    A large wildfire called the Las Conchas Fire burned large areas near Los Alamos National Laboratory (LANL) in 2011 and heightened public concern and news media attention over transuranic (TRU) waste stored at LANL’s Technical Area 54 (TA-54) Area G waste management facility. The removal of TRU waste from Area G had been placed at a lower priority in budget decisions for environmental cleanup at LANL because TRU waste removal is not included in the March 2005 Compliance Order on Consent (Reference 1) that is the primary regulatory driver for environmental cleanup at LANL. The Consent Order is an agreement between LANL and the New Mexico Environment Department (NMED) that contains specific requirements and schedules for cleaning up historical contamination at the LANL site. After the Las Conchas Fire, discussions were held by the U.S. Department of Energy (DOE) with the NMED on accelerating TRU waste removal from LANL and disposing it at the Waste Isolation Pilot Plant (WIPP). This report summarizes available information on the origin, configuration, and composition of the waste containers within the Hot Cell Liners category; their physical and radiological characteristics; the results of the radioassays; and the justification to reclassify the five containers as LLW rather than TRU waste.

  8. Disentangling above- and below-ground competition between lianas and trees in a tropical forest

    NARCIS (Netherlands)

    Schnitzer, S.A.; Kuzee, M.E.; Bongers, F.J.J.M.

    2005-01-01

    1 Light is thought to be the most limiting resource in tropical forests, and thus aboveground competition is commonly accepted as the mechanism that structures these communities. In many tropical forests, trees compete not only with other trees, but also with lianas, which compete aggressively for

  9. Equivalence in the strength of deer herbivory on above and below ground communities

    DEFF Research Database (Denmark)

    Lessard, Jean-Philippe; Reynolds, W. Nicholas; Bunn, Windy A.

    2012-01-01

    that herbivory would alter the composition and diversity of communities, but the strength of the effects of herbivory would weaken from plants, to leaf-litter invertebrates, and to belowground microarthropod communities. First, we found that herbivory negatively impacted plant seedling and sapling abundance...... and performance, reduced the abundance of ants and the taxonomic richness of arthropods in the litter layer and reduced the richness of soil microarthropod communities. Second, in contrast to our hypothesis, the magnitude of effect size did not vary among trophic levels, indicating that effects of deer herbivory...... cascade from plants to the leaf-litter and soil arthropod communities with equal strength. While much recent research has focused on how specific traits of plants may mediate the effects of herbivory on associated species, our results suggest that indirect effects of herbivory might influence many...

  10. Completing below-ground carbon budgets for pastures, recovering forests, and mature forests of Amazonia

    Science.gov (United States)

    Davidson, Eric A.; Nepstad, Daniel C.; Trumbore, Susan E.

    1995-01-01

    This progress report covers the following efforts initiated for the year: year-round monthly soil CO2 flux measurements were started in both primary and secondary forests and in managed and degraded pastures; root sorting and weighing has begun and all four ecosystems at Paragominas have been analyzed through samples; regional modeling of soil water dynamics and minimum rooting depth has been done and the RADAMBRASIL soils database has been digitized and a 20 year record of the precipitation for the region has been produced, along with a hydrological ('bucket-tipping') model that will run within a GIS framework; prototype tension lysimeters have been designed and installed in soil pits to begin assessing the importance of DOC as a source of organic matter in deep soils; and many publications, listed in this document, have resulted from this year's research. Two of the papers published are included with this annual report document.

  11. Effect of fertilization on below-ground plant mass of submontane Polygono-Cirsietum meadow

    Czech Academy of Sciences Publication Activity Database

    Holub, Petr; Tůma, I.; Fiala, Karel

    2013-01-01

    Roč. 6, č. 1 (2013), s. 33-42 ISSN 1803-2451 R&D Projects: GA ČR(CZ) GA526/06/0556; GA MZe QJ1220007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 ; RVO:67985939 Keywords : biomass partitioning * grassland * fertilization * primary productivity Subject RIV: EH - Ecology, Behaviour; EF - Botanics (BU-J)

  12. Information indices as a tool for quantifying development of below-ground terrestrial ecosystems

    NARCIS (Netherlands)

    Holtkamp, R.; Tobor-Kaplon, M.A.

    2007-01-01

    Information indices from ecosystem network analysis (ENA) describe the size and organization of an ecosystem and are claimed to quantify ecosystem development [Ulanowicz, R.E., 1986, Growth and Development, Springler-Verslag, New York, 203 pp.]. To date, these indices were not used to describe a

  13. Alternations of Structure and Functional Activity of Below Ground Microbial Communities at Elevated Atmospheric Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhili; Xu, Meiying; Deng, Ye; Kang, Sanghoon; Wu, Liyou; Van Nostrand, Joy D.; Hobbie, Sarah E.; Reich, Peter B.; Zhou, Jizhong

    2010-05-17

    The global atmospheric concentration of CO2 has increased by more than 30percent since the industrial revolution. Although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity have been well studied, its influences on belowground microbial communities are poorly understood and controversial. In this study, we showed a significant change in the structure and functional potential of soil microbial communities at eCO2 in a grassland ecosystem, the BioCON (Biodiversity, CO2 and Nitrogen) experimental site (http://www.biocon.umn.edu/) using a comprehensive functional gene array, GeoChip 3.0, which contains about 28,0000 probes and covers approximately 57,000 gene variants from 292 functional gene families involved in carbon, nitrogen, phosphorus and sulfur cycles as well as other functional processes. GeoChip data indicated that the functional structure of microbial communities was markedly different between ambient CO2 (aCO2) and eCO2 by detrended correspondence analysis (DCA) of all 5001 detected functional gene probes although no significant differences were detected in the overall microbial diversity. A further analysis of 1503 detected functional genes involved in C, N, P, and S cycles showed that a considerable portion (39percent) of them were only detected under either aCO2 (14percent) or eCO2 (25percent), indicating that the functional characteristics of the microbial community were significantly altered by eCO2. Also, for those shared genes (61percent) detected, some significantly (p<0.05) changed their abundance at eCO2. Especially, genes involved in labile C degradation, such as amyA, egl, and ara for starch, cellulose, and hemicelluloses, respectively, C fixation (e.g., rbcL, pcc/acc), N fixation (nifH), and phosphorus utilization (ppx) were significantly increased under eCO2, while those involved in decomposing recalcitrant C, such as glx, lip, and mnp for lignin degradation remained unchanged. This study provides insights into our understanding of belowground microbial communities and their feedbacks to terrestrial ecosystems at eCO2.

  14. Non-invasive monitoring of below ground cassava storage root bulking by ground penetrating radar technology

    Science.gov (United States)

    Ruiz Vera, U. M.; Larson, T. H.; Mwakanyamale, K. E.; Grennan, A. K.; Souza, A. P.; Ort, D. R.; Balikian, R. J.

    2017-12-01

    Agriculture needs a new technological revolution to be able to meet the food demands, to overcome weather and natural hazards events, and to monitor better crop productivity. Advanced technologies used in other fields have recently been applied in agriculture. Thus, imagine instrumentation has been applied to phenotype above-ground biomass and predict yield. However, the capability to monitor belowground biomass is still limited. There are some existing technologies available, for example the ground penetrating radar (GPR) which has been used widely in the area of geology and civil engineering to detect different kind of formations under the ground without the disruption of the soil. GPR technology has been used also to monitor tree roots but as yet not crop roots. Some limitation are that the GPR cannot discern roots smaller than 2 cm in diameter, but it make it feasible for application in tuber crops like Cassava since harvest diameter is greater than 4 cm. The objective of this research is to test the availability to use GPR technology to monitor the growth of cassava roots by testing this technique in the greenhouse and in the field. So far, results from the greenhouse suggest that GPR can detect mature roots of cassava and this data could be used to predict biomass.

  15. Dosimetry of Rn-222 in the air in environments located above and below ground level

    International Nuclear Information System (INIS)

    Cazula, Camila Dias

    2015-01-01

    Exposure of the general population to ionizing radiation comes mainly from natural sources. The main contribution is due to inhalation of radon (Rn-222), a gas that occurs naturally (UNSCEAR, 2000). The Rn-222 concentration in the environment is controlled by factors such as soil permeability and water content, the weather variability, materials used in the foundation and the usual positive pressure differential between the soil and the internal environment. Studies indicate that the concentration of radon shows a wide variation in the basement, ground floor and upper floors of buildings. The objective of this study is to determine radon levels in basements, ground floor and floors above ground level, at a university in the city of Sao Paulo and in one residential building in the city of Peruibe. Rn-222 measurements were performed using the method with nuclear track of solid state detectors (CR-39). The studied environments present Rn-222 concentration well below the values recommended by the International Commission on Radiological Protection, published in the 2009 document, of 300 Bq/m 3 for homes and 1000 Bq/m 3 for the workplace. In the residential building, the concentration of Ra-266, Th-232 and K-40 in the materials used in the building construction was also analyzed, by gamma spectrometry. The effective total dose for the resident due to external exposure was 0.8 mSv y -1 , lower than the annual dose limit for the general public of 1 mSv y -1 . (author)

  16. Testing the growth rate hypothesis in vascular plants with above- and below-ground biomass.

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    Full Text Available The growth rate hypothesis (GRH proposes that higher growth rate (the rate of change in biomass per unit biomass, μ is associated with higher P concentration and lower C:P and N:P ratios. However, the applicability of the GRH to vascular plants is not well-studied and few studies have been done on belowground biomass. Here we showed that, for aboveground, belowground and total biomass of three study species, μ was positively correlated with N:C under N limitation and positively correlated with P:C under P limitation. However, the N:P ratio was a unimodal function of μ, increasing for small values of μ, reaching a maximum, and then decreasing. The range of variations in μ was positively correlated with variation in C:N:P stoichiometry. Furthermore, μ and C:N:P ranges for aboveground biomass were negatively correlated with those for belowground. Our results confirm the well-known association of growth rate with tissue concentration of the limiting nutrient and provide empirical support for recent theoretical formulations.

  17. EPN Chemical ecology and new techniques for below ground sampling and analyses of volatile semiochemicals

    Science.gov (United States)

    It is well established that herbivory induced plant volatiles (HIPVs) attract natural enemies of the herbivores. Utilizing this plant response has become a fundamental part of above ground IPM programs. We now know that also roots can release HIPVs and that these compounds attract beneficial organis...

  18. Links between plant litter chemistry, species diversity, and below-ground ecosystem function

    OpenAIRE

    Meier, Courtney L.; Bowman, William D.

    2008-01-01

    Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics...

  19. and below-ground biomass partitioning in two arid-zone dwarf shrubs

    African Journals Online (AJOL)

    ground fractions could be influenced by plant adaptations to herbivory. The response of potted Indigofera spinosa and I. cliffordiana to heavy and moderate top defoliations, compared to non-defoliated controls, was investigated. Relative growth ...

  20. 33 Shafts Category of Transuranic Waste Stored Below Ground within Area G

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Kenneth Marshall [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Monk, Thomas H [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-22

    This report compiles information to support the evaluation of alternatives and analysis of regulatory paths forward for the 33 shafts. The historical information includes a form completed by waste generators for each waste package (Reference 6) that included a waste description, estimates of Pu-239 and uranium-235 (U-235) based on an accounting technique, and calculations of mixed fission products (MFP) based on radiation measurements. A 1979 letter and questionnaire (Reference 7) provides information on waste packaging of hot cell waste and the configuration of disposal shafts as storage in the 33 Shafts was initiated. Tables of data by waste package were developed during a review of historical documents that was performed in 2005 (Reference 8). Radiological data was coupled with material-type data to estimate the initial isotopic content of each waste package and an Oak Ridge National Laboratory computer code was used to calculate 2009 decay levels. Other sources of information include a waste disposal logbook for the 33 shafts (Reference 9), reports that summarize remote-handled waste generated at the CMR facility (Reference 10) and placement of waste in the 33 shafts (Reference 11), a report on decommissioning of the LAMPRE reactor (Reference 12), interviews with an employee and manager involved in placing waste in the 33 shafts (References 13 and 14), an interview with a long-time LANL employee involved in waste operations (Reference 15), a 2002 plan for disposition of remote-handled TRU waste (Reference 16), and photographs obtained during field surveys of several shafts in 2007. The WIPP Central Characterization Project (CCP) completed an Acceptable Knowledge (AK) summary report for 16 canisters of remote-handled waste from the CMR Facility that contains information relevant to the 33 Shafts on hot-cell operations and timeline (Reference 17).

  1. Picturing Adoption of Below-Ground Biodiversity Technologies among Smallholder Farmers around Mabira Forest, Uganda

    Directory of Open Access Journals (Sweden)

    Isabirye, BE.

    2010-01-01

    Full Text Available Faced with a multitude of soil and water amendment technologies, farmers have the task of choosing the technologies to adopt for ensuring subsistence and income sustainability. In 2008, a study to characterize the farmers was conducted around Mabira Forest, to assess the adoption of soil technologies fostering Belowground Biodiversity (BGBD. Eighty-four households (38 participating and 46 non-participants from four villages were randomly selected and interviewed. Results showed that the adoption pattern was significantly driven by farm size, labor, household size, age and wealth status of the house. Also important were farm location, gender of household head, primary occupation, soil and water conservation technologies training, land tenure, and social capital. For the few current adopters, there was a perceived increase in labor demand but overall productivity was higher, partly resulting from increased crop productivity due to soil fertility enhancement and soil structure modification. It is therefore concluded that, around Mabira forest, BGBD technologies will be adopted by farming households with sufficient land, labor and social capital.

  2. Silicon's Role in Abiotic and Biotic Plant Stresses.

    Science.gov (United States)

    Debona, Daniel; Rodrigues, Fabrício A; Datnoff, Lawrence E

    2017-08-04

    Silicon (Si) plays a pivotal role in the nutritional status of a wide variety of monocot and dicot plant species and helps them, whether directly or indirectly, counteract abiotic and/or biotic stresses. In general, plants with a high root or shoot Si concentration are less prone to pest attack and exhibit enhanced tolerance to abiotic stresses such as drought, low temperature, or metal toxicity. However, the most remarkable effect of Si is the reduction in the intensities of a number of seedborne, soilborne, and foliar diseases in many economically important crops that are caused by biotrophic, hemibiotrophic, and necrotrophic plant pathogens. The reduction in disease symptom expression is due to the effect of Si on some components of host resistance, including incubation period, lesion size, and lesion number. The mechanical barrier formed by the polymerization of Si beneath the cuticle and in the cell walls was the first proposed hypothesis to explain how this element reduced the severity of plant diseases. However, new insights have revealed that many plant species supplied with Si have the phenylpropanoid and terpenoid pathways potentiated and have a faster and stronger transcription of defense genes and higher activities of defense enzymes. Photosynthesis and the antioxidant system are also improved for Si-supplied plants. Although the current understanding of how this overlooked element improves plant reaction against pathogen infections, pest attacks, and abiotic stresses has advanced, the exact mechanism(s) by which it modulates plant physiology through the potentiation of host defense mechanisms still needs further investigation at the genomic, metabolomic, and proteomic levels.

  3. The timing and pattern of biotic recovery following the end-Permian mass extinction

    Science.gov (United States)

    Chen, Zhong-Qiang; Benton, Michael J.

    2012-06-01

    The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of >90% species globally. The crisis was triggered by a number of physical environmental shocks (global warming, acid rain, ocean acidification and ocean anoxia), and some of these were repeated over the next 5-6 Myr. Ammonoids and some other groups diversified rapidly, within 1-3 Myr, but extinctions continued through the Early Triassic period. Triassic ecosystems were rebuilt stepwise from low to high trophic levels through the Early to Middle Triassic, and a stable, complex ecosystem did not re-emerge until the beginning of the Middle Triassic, 8-9 Myr after the crisis. A positive aspect of the recovery was the emergence of entirely new groups, such as marine reptiles and decapod crustaceans, as well as new tetrapods on land, including -- eventually -- dinosaurs. The stepwise recovery of life in the Triassic could have been delayed either by biotic drivers (complex multispecies interactions) or physical perturbations, or a combination of both. This is an example of the wider debate about the relative roles of intrinsic and extrinsic drivers of large-scale evolution.

  4. Uncertainty result of biotic index in analysing the water quality of Cikapundung river catchment area, Bandung

    Science.gov (United States)

    Surtikanti, Hertien Koosbandiah

    2017-05-01

    The Biotic Index was developed in Western Countries in response to the need in water quality evaluation. This method analysis is based on the classification of aquatic macrobenthos as a bioindicator for clean and polluted water. The aim of this study is to compare the analysis of Cikapundung river using 6 different Biotic Indexes. BI Shannon-Weiner, Belgian Biological Index (BBI), Family Biotic Index (FBI), Biological Monitoring Working Party (BMWP), Biological Monitoring Working Party-Average Score Per Taxon (BMWP-ASPT), and A Scoring System for Macroinvertebrate in Australian River (A SIGNAL). Those analysis are compared with Physical Water Index (CPI) which is developed in Indonesia. The result shows that a decreasing water quality is detected upstream to downstream of Cikapundung River. However, based on the CPI analysis result, the BMWP-ASPT biotic index analysis is more comprehensive than other BI in explaining Cikapundung water quality.

  5. Distribution of mercury in different abiotic and biotic sectors of the Mandovi-Zuari estuary (Goa)

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, M.; Mesquita, A.; Ray, D.; Fernandes, B.

    This study highlights the behaviour of Mercury in the abiotic and biotic segments of the Mandovi-Zuari estuarine system Spatia l, seasonal (Premonsoon and Postmonsoon) and tidal, distribution of THg in dissolved/particulate fractions, sediment...

  6. Quantitative patterns between plant volatile emissions induced by biotic stresses and the degree of damage

    Directory of Open Access Journals (Sweden)

    Ülo eNiinemets

    2013-07-01

    Full Text Available Plants have to cope with a plethora of biotic stresses such as herbivory and pathogen attacks throughout their life cycle. The biotic stresses typically trigger rapid emissions of volatile products of lipoxygenase pathway (LOX products, various C6 aldehydes, alcohols and derivatives, also called green leaf volatiles associated with oxidative burst. Further a variety of defense pathways is activated, leading to induction of synthesis and emission of a complex blend of volatiles, often including methyl salicylate, indole, mono-, homo- and sesquiterpenes. The airborne volatiles are involved in systemic responses leading to elicitation of emissions from non-damaged plant parts. For several abiotic stresses, it has been demonstrated that volatile emissions are quantitatively related to the stress dose. The biotic impacts under natural conditions vary in severity from mild to severe, but it is unclear whether volatile emissions also scale with the severity of biotic stresses in a dose-dependent manner. Furthermore, biotic impacts are typically recurrent, but it is poorly understood how direct stress-triggered and systemic emission responses are silenced during periods intervening sequential stress events. Here we review the information on induced emissions elicited in response to biotic attacks, and argue that biotic stress severity vs. emission rate relationships should follow principally the same dose-response relationships as previously demonstrated for several abiotic stresses. Analysis of several case studies investigating the elicitation of emissions in response to chewing herbivores, aphids, rust fungi, powdery mildew and Botrytis, suggests that induced emissions do respond to stress severity in dose-dependent manner. Bi-phasic emission kinetics of several induced volatiles have been demonstrated in these experiments, suggesting that next to immediate stress-triggered emissions, biotic stress elicited emissions typically have a secondary

  7. The suitability of the marine biotic index (AMBI) to new impact sources along European coasts

    OpenAIRE

    Muxika, I.; Borja, A.; Bonne, W.

    2005-01-01

    In recent years, several benthic biotic indices have been proposed to be used as ecological indicators in estuarine and coastal waters. One such indicator, the AZTI Marine Biotic Index (AMBI), was designed to establish the ecological quality of European coasts. The index examined the response of soft-bottom benthic communities to natural and man-induced disturbances in coastal and estuarine environments. It has been successfully applied to different geographical areas and under different impa...

  8. The role of biotic forces in driving macroevolution: beyond the Red Queen.

    Science.gov (United States)

    Voje, Kjetil L; Holen, Øistein H; Liow, Lee Hsiang; Stenseth, Nils Chr

    2015-06-07

    A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  9. The role of biotic forces in driving macroevolution: beyond the Red Queen

    Science.gov (United States)

    Voje, Kjetil L.; Holen, Øistein H.; Liow, Lee Hsiang; Stenseth, Nils Chr.

    2015-01-01

    A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution. PMID:25948685

  10. Metabolomic changes of Brassica rapa under biotic stress

    NARCIS (Netherlands)

    Abdel-Farid Ali, Ibrahim Bayoumi

    2009-01-01

    It has been shown by this thesis that plant metabolomics is a promising tool for studying the interaction between B. rapa and pathogenic fungi. It gives a picture of the plant metabolites during the interaction. Brassica rapa has many defense related compounds such as glucosinolates, IAA,

  11. Coupled Abiotic-Biotic Degradation of Bisphenol A

    Science.gov (United States)

    Im, J.; Prevatte, C.; Campagna, S. R.; Loeffler, F.

    2014-12-01

    Bisphenol A (BPA) is a ubiquitous environmental contaminant with weak estrogenic activity. BPA is readily biodegradable with oxygen available, but is recalcitrant to microbial degradation under anoxic conditions. However, BPA is susceptible to abiotic transformation under anoxic conditions. To better understand the fate of BPA in anoxic environments, the kinetics of BPA transformation by manganese oxide (d-MnO2) were investigated. BPA was rapidly transformed by MnO2 with a pseudo-first-order rate constant of 0.413 min-1. NMR and LC-MS analyses identified 4-hydroxycumyl alcohol (HCA) as a major intermediate. Up to 64% of the initial amount of BPA was recovered as HCA within 5 min, but the conversion efficiency decreased with time, suggesting that HCA was further degraded by MnO2. Further experiments confirmed that HCA was also susceptible to transformation by MnO2, albeit at 5-fold lower rates than BPA transformation. Mass balance approaches suggested that HCA was the major BPA transformation intermediate, but other compounds may also be formed. The abiotic transformation of BPA by MnO2 was affected by pH, and 10-fold higher transformation rates were observed at pH 4.5 than at pH 10. Compared to BPA, HCA has a lower octanol-water partitioning coefficient (Log Kow) of 0.76 vs 2.76 for BPA and a higher aqueous solubility of 2.65 g L-1 vs 0.31 g L-1 for BPA, suggesting higher mobility of HCA in the environment. Microcosms established with freshwater sediment materials collected from four geographically distinct locations and amended with HCA demonstrated rapid HCA biodegradation under oxic, but not under anoxic conditions. These findings suggest that BPA is not inert under anoxic conditions and abiotic reactions with MnO2 generate HCA, which has increased mobility and is susceptible to aerobic degradation. Therefore, coupled abiotic-biotic processes can affect the fate and longevity of BPA in terrestrial environments.

  12. [Effect of abiotic and biotic factors on the structural and functional organization of the saline lake ecosystems in Crimea].

    Science.gov (United States)

    Balushkina, E V; Golubkov, S M; Golubkov, M S; Litvinchuk, L F; Shadrin, N V

    2009-01-01

    Decrease of both zooplankton and zoobenthos species richness and a trend toward decrease of their biomass with the salinity increase was recorded in the hypersaline lakes of Crimea. The most of structural and functional characteristics of macrobenthos is positively correlated with abiotic and biotic characteristics of those lakes. Abundance, biomass, productivity of macrobenthos and ration of non-predating macrozoobenthos decrease with salinity increase, while they increase with the depth and growth of amount of chlorophyll a and primary production. Macrozoobenthos portion in the total zooplankton and macrozoobenthos biomass decreases with both salinity and depth increase. Zooplankton community is less controlled by abiotic factors as compared to macrozoobenthos, while the former's species number significantly decrease with salinity increase. Effect of salinity on zooplankton biomass is slightly significant, unlike that of macrozoobenthos. Comparison of total amount of rations of zooplankton and macrozoobenthos with amount of primary production indicates intense trophic interactions in the lakes under study.

  13. Are Free Ion Activity Models Sufficient Alternatives to Biotic Ligand Models in Evaluating Metal Toxic Impacts in Terrestrial Environments?

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Larsen, Henrik Fred

    Metal partitioning between solid and aqueous phases and speciation in soil pore water control the bioavailability of toxic forms of metals, while protons and base cations can mitigate metal ecotoxicity by competitive interactions with biotic ligands. e employment of BLMs to evaluate toxicity...... potential of metals in soils results in site-specic toxicity scores due to large variability of soil properties and dierences in ionic composition. Unfortunately, terrestrial BMLs are available only for few metals and few organisms, thus their applicability to hazard ranking or toxic impact assessment...... is low and alternatives must be found. In this study, we compared published terrestrial BLMs and their potential alternatives such as free ion activity models (FIAM), for applicability in addressing metal toxic impacts in terrestrial environments. A set of 1300 soils representative for the whole world...

  14. Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe0 and mixed anaerobic culture.

    Science.gov (United States)

    Zhong, Jiawei; Yin, Weizhao; Li, Yongtao; Li, Ping; Wu, Jinhua; Jiang, Gangbiao; Gu, Jingjing; Liang, Hao

    2017-10-01

    In this study, Fe 0 and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe 0 column in the control experiments. According to the breakthrough study, a slower Cr(VI) breakthrough rate of 0.19 cm/PV was observed in the biotic Fe 0 column whereas the value in the abiotic Fe 0 column was 0.30 cm/PV, resulting in 64% longer life-span and 62% higher Cr(VI) removal capacity in the biotic Fe 0 column than the abiotic one. The solid phase characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) confirmed that this enhancement was attributed to the higher consumption of iron and greater production of diverse reactive minerals (e.g., green rust, magnetite and lepidocrocite) induced by the synergistic interaction of Fe 0 and anaerobic culture, providing more reactive sites for Cr(VI) adsorption, reduction and co-precipitation. Furthermore, the decreasing breakthrough rates and growing iron corrosion along the biotic Fe 0 column demonstrated an inhomogeneous distribution of reactive zones in the column and its latter 3/5 section was considered to be the most reactive area for Cr(VI) removal. These results indicate that the inoculation of microorganisms in Fe 0 -based permeable reactive barriers will enable this technology a higher removal capacity and longer life-span for the remediation of Cr(VI)-contaminated groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Abiotic Versus Biotic Pathogens: Replicative Growth in Host Tissues Key to Discriminating Between Biotoxic Injury and Active Pathogenesis

    Science.gov (United States)

    Schuerger, Andrew C.; Ming, Douglas W.; Golden, D. C.

    2012-01-01

    Life can be defined as a self-sustaining chemical system capable of undergoing Darwinian evolution; a self-bounded, self-replicating, and self-perpetuating entity [1]. This definition should hold for terrestrial as well as extraterrestrial life-forms. Although, it is reasonable to expect that a Mars life-form would be more adaptable to Mars-like conditions than to Earth-like environments, it remains possible that negative ecological or host interactions might occur if Mars microbiota were to be inadvertently released into the terrestrial environment. A biogenic infectious agent can be defined as a self-sustaining chemical system capable of undergoing Darwinian evolution and derives its sustenance from a living cell or from the by-products of cell death. Disease can be de-fined as the detrimental alteration of one or more ordered metabolic processes in a living host caused by the continued irritation of a primary causal factor or factors; disease is a dynamic process [2]. In contrast, an injury is due to an instantaneous event; injury is not a dynamic process [2]. A causal agent of disease is defined as a pathogen, and can be either abiotic or biotic in nature. Diseases incited by biotic pathogens are the exceptions, not the norms, in terrestrial host-microbe interactions. Disease induction in a plant host can be conceptually characterized using the Disease Triangle (Fig. 1) in which disease occurs only when all host, pathogen, and environ-mental factors that contribute to the development of disease are within conducive ranges for a necessary minimum period of time. For example, plant infection and disease caused by the wheat leaf rust fungus, Puccinia recondita, occur only if virulent spores adhere to genetically susceptible host tissues for at least 4-6 hours under favorable conditions of temperature and moisture [3]. As long as one or more conditions required for disease initiation are not available, disease symptoms will not develop.

  16. Biotic interaction between earthworms and pesticide degrading bacteria - Impact on the detoxification service of soil

    OpenAIRE

    Monard, Cécile; Vandenkoornhuyse, Philippe; Martin-Laurent, Fabrice; Binet, Françoise

    2010-01-01

    Earthworms are efficient soil engineers that change the physical and chemical properties of soil and act in turn on soil microbial communities. Earthworm bioturbation will thus impact microbial processes in soil and also the generated ecosystemic services such as detoxification function. By using RNA based Stable Isotope Probing we demonstrated that the bacterial communities responsive to 13 C enrichments in earthworm casts were different from those in bulk soil resulting in different degrada...

  17. Impact of global changes and biotic interactions on food webs in lakes

    DEFF Research Database (Denmark)

    Vidal, Nicolas

    The last decades have witnessed unprecedented changes at a global scale including, among others, an increasing human population and goods consumption rates, climate change (warming, changes in precipitation regime), species invasions and globalisation of trade, among others. Aquatic systems...... are exposed to several of these stressors, shallow lakes being particularly vulnerable. Shallow lakes are the most abundant lake type on Earth, hold great biodiversity and act as very important sources of ecosystem services by providing, among other things, drinking water and food. Eutrophication is one...

  18. Genomics of Secondary Metabolism in Populus: Interactions with Biotic and Abiotic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F.; Liu, C.; Tschaplinski, T. J.; Zhao, N.

    2009-09-01

    Populus trees face constant challenges from the environment during their life cycle. To ensure their survival and reproduction, Populus trees deploy various types of defenses, one of which is the production of a myriad of secondary metabolites. Compounds derived from the shikimate-phenylpropanoid pathway are the most abundant class of secondary metabolites synthesized in Populus. Among other major classes of secondary metabolites in Populus are terpenoids and fatty acid-derivatives. Some of the secondary metabolites made by Populus trees have been functionally characterized. Some others have been associated with certain biological/ecological processes, such as defense against insects and microbial pathogens or acclimation or adaptation to abiotic stresses. Functions of many Populus secondary metabolites remain unclear. The advent of various novel genomic tools will enable us to explore in greater detail the complexity of secondary metabolism in Populus. Detailed data mining of the Populus genome sequence can unveil candidate genes of secondary metabolism. Metabolomic analysis will continue to identify new metabolites synthesized in Populus. Integrated genomics that combines various 'omics' tools will prove to be the most powerful approach in revealing the molecular and biochemical basis underlying the biosynthesis of secondary metabolites in Populus. Characterization of the biological/ecological functions of secondary metabolites as well as their biosynthesis will provide knowledge and tools for genetically engineering the production of seconday metabolites that can lead to the generation of novel, improved Populus varieties.

  19. Aerobic bacterial catabolism of persistent organic pollutants - potential impact of biotic and abiotic interaction

    Czech Academy of Sciences Publication Activity Database

    Jeon, J.-R.; Murugesan, K.; Baldrian, Petr; Schmidt, S.; Chang, Y.-S.

    2016-01-01

    Roč. 38, APR 2016 (2016), s. 71-78 ISSN 0958-1669 Institutional support: RVO:61388971 Keywords : ZERO-VALENT IRON * POLYBROMINATED DIPHENYL ETHERS * CHEMICAL-BIOLOGICAL TREATMENT Subject RIV: EE - Microbiology, Virology Impact factor: 9.294, year: 2016

  20. Impact of global changes and biotic interactions on food webs in lakes

    DEFF Research Database (Denmark)

    Vidal, Nicolas

    ). This impact seemed to be less drastic in clear water lakes, but the direct effect of exotic fishes predation (consumption) on native fishes was, contrary to our expectations, stronger in the turbid lakes. However, only weak cascading effects of predator introduction were detected; the size of calanoid......The last decades have witnessed unprecedented changes at a global scale including, among others, an increasing human population and goods consumption rates, climate change (warming, changes in precipitation regime), species invasions and globalisation of trade, among others. Aquatic systems...... are exposed to several of these stressors, shallow lakes being particularly vulnerable. Shallow lakes are the most abundant lake type on Earth, hold great biodiversity and act as very important sources of ecosystem services by providing, among other things, drinking water and food. Eutrophication is one...

  1. Effect of abiotic and biotic stress factors analysis using machine learning methods in zebrafish.

    Science.gov (United States)

    Gutha, Rajasekar; Yarrappagaari, Suresh; Thopireddy, Lavanya; Reddy, Kesireddy Sathyavelu; Saddala, Rajeswara Reddy

    2018-03-01

    In order to understand the mechanisms underlying stress responses, meta-analysis of transcriptome is made to identify differentially expressed genes (DEGs) and their biological, molecular and cellular mechanisms in response to stressors. The present study is aimed at identifying the effect of abiotic and biotic stress factors, and it is found that several stress responsive genes are common for both abiotic and biotic stress factors in zebrafish. The meta-analysis of micro-array studies revealed that almost 4.7% i.e., 108 common DEGs are differentially regulated between abiotic and biotic stresses. This shows that there is a global coordination and fine-tuning of gene regulation in response to these two types of challenges. We also performed dimension reduction methods, principal component analysis, and partial least squares discriminant analysis which are able to segregate abiotic and biotic stresses into separate entities. The supervised machine learning model, recursive-support vector machine, could classify abiotic and biotic stresses with 100% accuracy using a subset of DEGs. Beside these methods, the random forests decision tree model classified five out of 8 stress conditions with high accuracy. Finally, Functional enrichment analysis revealed the different gene ontology terms, transcription factors and miRNAs factors in the regulation of stress responses. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Trophic cascades, invasive species and body-size hierarchies interactively modulate climate change responses of ecotonal temperate-boreal forest.

    Science.gov (United States)

    Frelich, Lee E; Peterson, Rolf O; Dovčiak, Martin; Reich, Peter B; Vucetich, John A; Eisenhauer, Nico

    2012-11-05

    As the climate warms, boreal tree species are expected to be gradually replaced by temperate species within the southern boreal forest. Warming will be accompanied by changes in above- and below-ground consumers: large moose (Alces alces) replaced by smaller deer (Odocoileus virginianus) above-ground, and small detritivores replaced by larger exotic earthworms below-ground. These shifts may induce a cascade of ecological impacts across trophic levels that could alter the boreal to temperate forest transition. Deer are more likely to browse saplings of temperate tree species, and European earthworms favour seedlings of boreal tree species more than temperate species, potentially hindering the ability of temperate tree species to expand northwards. We hypothesize that warming-induced changes in consumers will lead to novel plant communities by changing the filter on plant species success, and that above- and below-ground cascades of trophic interactions will allow boreal tree species to persist during early phases of warming, leading to an abrupt change at a later time. The synthesis of evidence suggests that consumers can modify the climate change-induced transition of ecosystems.

  3. Interacting effects of insects and flooding on wood decomposition.

    Directory of Open Access Journals (Sweden)

    Michael D Ulyshen

    Full Text Available Saproxylic arthropods are thought to play an important role in wood decomposition but very few efforts have been made to quantify their contributions to the process and the factors controlling their activities are not well understood. In the current study, mesh exclusion bags were used to quantify how arthropods affect loblolly pine (Pinus taeda L. decomposition rates in both seasonally flooded and unflooded forests over a 31-month period in the southeastern United States. Wood specific gravity (based on initial wood volume was significantly lower in bolts placed in unflooded forests and for those unprotected from insects. Approximately 20.5% and 13.7% of specific gravity loss after 31 months was attributable to insect activity in flooded and unflooded forests, respectively. Importantly, minimal between-treatment differences in water content and the results from a novel test carried out separately suggest the mesh bags had no significant impact on wood mass loss beyond the exclusion of insects. Subterranean termites (Isoptera: Rhinotermitidae: Reticulitermes spp. were 5-6 times more active below-ground in unflooded forests compared to flooded forests based on wooden monitoring stakes. They were also slightly more active above-ground in unflooded forests but these differences were not statistically significant. Similarly, seasonal flooding had no detectable effect on above-ground beetle (Coleoptera richness or abundance. Although seasonal flooding strongly reduced Reticulitermes activity below-ground, it can be concluded from an insignificant interaction between forest type and exclusion treatment that reduced above-ground decomposition rates in seasonally flooded forests were due largely to suppressed microbial activity at those locations. The findings from this study indicate that southeastern U.S. arthropod communities accelerate above-ground wood decomposition significantly and to a similar extent in both flooded and unflooded forests

  4. Interaction webs in arctic ecosystems

    DEFF Research Database (Denmark)

    Schmidt, Niels M.; Hardwick, Bess; Gilg, Olivier

    2017-01-01

    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they ...... that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems....

  5. Do Karst Rivers “deserve” their own biotic index? A ten years study on macrozoobenthos in Croatia

    Directory of Open Access Journals (Sweden)

    Rađa Biljana

    2010-07-01

    Full Text Available In this study we present the results of a ten year survey of the aquatic macroinvertebrate fauna along four karst rivers: Jadro, Žrnovnica, Grab and Ruda, all of them situated in the Middle Dalmatia region of Croatia, in an attempt to construct the Iliric Biotic Index, which will be more applicable for the water quality analysis than the most frequently applied biotic index in Croatia, the Italian Modification of Extended Biotic Index. The rivers geologically belong to the Dinaric karst, unique geological phenomena in Europe. Benthic macroinvertebrates were collected along each river at 15 sites by standard methods of sampling along with several physicochemical parameters, including: temperature, dissolved oxygen, carbon dioxide, alkalinity, hardness and pH. Univariate and multivariate techniques revealed differences in the macroinvertebrate community structure as well as in physicochemical parameters between the Karst rivers and continental rivers. Based on those differences, the Iliric Biotic Index was proposed as the standard of karst river water quality in Croatia in accordance with the EU Water Framework Directive. Differences between the Iliric Biotic Index and the most commonly used biotic indices in the European Community and the USA (The Biological Monitoring Working Party (B.M.W.P. scores, i.e. Extended Biotic Index, Indice Biotique, Family Biotic Index suggest that karst rivers need a new biotic index.

  6. Overexpression of VOZ2 confers biotic stress tolerance but decreases abiotic stress resistance in Arabidopsis.

    Science.gov (United States)

    Nakai, Yusuke; Fujiwara, Sumire; Kubo, Yasuyuki; Sato, Masa H

    2013-03-01

    VOZ (vascular plant one zinc-finger protein) is a plant specific one-zinc finger type transcriptional activator, which is highly conserved through land plant evolution. We have previously shown that loss-of-function mutations in VOZ1 and VOZ2 showed increased cold and drought stress tolerances whereas decreased biotic stress resistance in Arabidopsis. Here, we demonstrate that transgenic plants overexpressing VOZ2 impairs freezing and drought stress tolerances but increases resistance to a fungal pathogen, Colletoricum higginsianum. Consistent with changes in the tolerance to biotic and abiotic stresses, the expression of marker genes for these stresses is significantly altered compared with those of the wild-type plant. These results indicate that a overexpression of VOZ2 confers biotic stress tolerance but impairs abiotic stress tolerances in Arabidopsis.

  7. Utilizing Genetic Resources and Precision Agriculture to Enhance Resistance to Biotic and Abiotic Stress in Watermelon

    Directory of Open Access Journals (Sweden)

    Mihail KANTOR

    2018-03-01

    Full Text Available Originally from Africa, watermelon is a staple crop in South Carolina and rich source of important phytochemicals that promote human health. As a result of many years of domestication and selection for desired fruit quality, modern watermelon cultivars are susceptible to biotic and abiotic stress. The present review discusses how genetic selection and breeding combined with geospatial technologies (precision agriculture may help enhance watermelon varieties for resistance to biotic and abiotic stress. Gene loci identified and selected in undomesticated watermelon accessions are responsible for resistance to diseases, pests and abiotic stress. Vegetable breeding programs use traditional breeding methodologies and genomic tools to introduce gene loci conferring biotic or abiotic resistance into the genome background of elite watermelon cultivars. This continuous approach of collecting, evaluating and identifying useful genetic material is valuable for enhancing genetic diversity and tolerance and combined with precision agriculture could increase food security in the Southeast.

  8. Application of Irradiated Pro biotic Microorganism in Black Tiger Shrimp (Penaeus monodon Fabricius) Culture

    International Nuclear Information System (INIS)

    Areechon, Nontawith; Purivrojkul, Watchariya; Srisapoome, Prapansak; Piadiang, Nattaya

    2006-09-01

    Marine shrimp culture in Thailand has been developed continuously for the past two decades. This development will ensure the highest level of shrimp quality that will be suitable for the consumption of the people in the country and also aboard. The trend of culture system emphasizes on disease prevention more than treatment which will consequently limit the application of drug and chemicals. Application of pro biotic has been one means of this prevention that are commonly practiced by shrimp farmers. This research was conducted to compare the efficacy of normal Bacillus subtilis isolate from shrimp intestine and an irradiated B. subtilis as a pro biotic in shrimp feed. It was found that overall results were quite the same. These included the broth Co-culture assay. Effects on immune functions were conducted with Penaeus monodon with initial average weight of 17 gms by feeding with 3 gms/kg feed of spore of these two pro biotic for two mouths. The results indicated that both pro biotic caused significant improvement on percent phagocytosis only at the forth week of feeding trial and the overall enhancement of bactericidal activity. However, total haemocyte count and phenoloxidase activity were not altered. Total bacterial count in shrimp intestine was also conducted during the two month trial. the results indicated significant reduction of Vibrio spp. of both pro biotic groups when compared with the control. Number of Bacillus spp. in intestine were continuously high even after pro biotic treatment had been stopped Growth rate of experiment and control shrimp was not significantly different.

  9. WATER QUALITY ANALYSIS OF LOTIC ECOSYSTEMS FROM UPPER MUREŞ RIVER CATCHMENT AREA USING DIFFERENT BIOTIC INDICES

    Directory of Open Access Journals (Sweden)

    Milca PETROVICI

    2012-01-01

    Full Text Available Present paper approach the issue of assessing the water quality of tributaries located in the upper basin of the river Mureş, taking into account changes in the value of biotic indices. In this sense, have been selected the next five biotic indices: Ephemeroptera Plecoptera Trichoptera index (EPT, Total Invertebrates index (T, Chironomidae index (Ch, EPT / Total invertebrates index (EPT / T, EPT / Chironomidae index (EPT / Ch and % Chironomidae index (% Chironomidae. Considering all these indices, it was found existence of a medium to best quality water in Mureş tributaries from Harghita Mountains and a good quality water which comes from the Maramureş Mountains and Transylvania Plateau.

  10. Are pine plantations valid tools for restoring Mediterranean forests? An assessment along abiotic and biotic gradients.

    Science.gov (United States)

    Gómez-Aparicio, Lorena; Zavala, Miguel A; Bonet, Francisco J; Zamora, Regino

    2009-12-01

    The ecological impacts of forest plantations are a focus of intense debate, from studies that consider plantations as "biological deserts" to studies showing positive effects on plant diversity and dynamics. This lack of consensus might be influenced by the scarcity of studies that examine how the ecological characteristics of plantations vary along abiotic and biotic gradients. Here we conducted a large-scale assessment of plant regeneration and diversity in plantations of southern Spain. Tree seedling and sapling density, plant species richness, and Shannon's (H') diversity index were analyzed in 442 pine plantation plots covering a wide gradient of climatic conditions, stand density, and distance to natural forests that act as seed sources. Pronounced variation in regeneration and diversity was found in plantation understories along the gradients explored. Low- to mid-altitude plantations showed a diverse and abundant seedling bank dominated by Quercus ilex, whereas high-altitude plantations showed a virtually monospecific seeding bank of Pinus sylvestris. Regeneration was null in plantations with stand densities exceeding 1500 pines/ha. Moderate plantation densities (500-1000 pines/ha) promoted recruitment in comparison to low or null canopy cover, suggesting the existence of facilitative interactions. Quercus ilex recruitment diminished exponentially with distance to the nearest Q. ilex forest. Richness and H' index values showed a hump-shaped distribution along the altitudinal and radiation gradients and decreased monotonically along the stand density gradient. From a management perspective, different strategies will be necessary depending on where a plantation lies along the gradients explored. Active management will be required in high-density plantations with arrested succession and low diversity. Thinning could redirect plantations toward more natural densities where facilitation predominates. Passive management might be recommended for low- to moderate

  11. Using biotechnology and genomics to improve biotic and abiotic stress in apple

    Science.gov (United States)

    Genomic sequencing, molecular biology, and transformation technologies are providing valuable tools to better understand the complexity of how plants develop, function, and respond to biotic and abiotic stress. These approaches should complement but not replace a solid understanding of whole plant ...

  12. Ecosystem services in grassland associated with biotic and abiotic soil parameters

    NARCIS (Netherlands)

    Eekeren, van N.J.M.; Boer, de Herman; Hanegraaf, M.C.; Bokhorst, J.; Nierop, D.; Bloem, J.; Schouten, T.; Goede, de R.G.M.; Brussaard, L.

    2010-01-01

    Biotic soil parameters have so far seldom played a role in practical soil assessment and management of grasslands. However, the ongoing reduction of external inputs in agriculture would imply an increasing reliance on ecosystem self-regulating processes. Since soil biota play an important role in

  13. Environmental and biotic controls over aboveground biomass throughout a tropical rainforest

    Science.gov (United States)

    G.P. Asner; R.F. Hughes; T.A. Varga; D.E. Knapp; T. Kennedy-Bowdoin

    2009-01-01

    The environmental and biotic factors affecting spatial variation in canopy three-dimensional (3-D) structure and aboveground tree biomass (AGB) are poorly understood in tropical rain forests. We combined field measurements and airborne light detection and ranging (lidar) to quantify 3-D structure and AGB across a 5,016 ha rain forest reserve on the...

  14. Genetics and regulation of combined abiotic and biotic stress tolerance in tomato

    NARCIS (Netherlands)

    Kissoudis, C.

    2016-01-01

    Projections on the impact of climate change on agricultural productivity foresee prolonged and/or increased stress intensities and enlargement of a significant number of pathogens habitats. This significantly raises the occurrence probability of (new) abiotic and biotic stress combinations. With

  15. Biotic perspective of the Deccan volcanism and India–Asia collision ...

    Indian Academy of Sciences (India)

    India's physical and biotic links after its separation from the former assembly of southern continents. (Gondwanaland) continue to evoke global .... provides further evidence in favour of terres- trial links between Indo–Madagascar and .... fragments, teeth and rare bones) in several inter- trappean localities led to the general ...

  16. Genetics and regulation of combined abiotic and biotic stress tolerance in tomato

    NARCIS (Netherlands)

    Kissoudis, C.

    2016-01-01

    Projections on the impact of climate change on agricultural productivity foresee prolonged and/or increased stress intensities and enlargement of a significant number of pathogens habitats. This significantly raises the occurrence probability of (new) abiotic and biotic stress combinations. With

  17. Effects of biotic disturbances on forest carbon cycling in the United States and Canada

    Science.gov (United States)

    Jeffrey A. Hicke; Craig D. Allen; Ankur R. Desai; Michael C. Dietze; Ronald J. Hall; Edward H. Hogg; Daniel M. Kashian; David Moore; Kenneth F. Raffa; Rona N. Sturrock; James. Vogelmann

    2011-01-01

    Forest insects and pathogens are major disturbance agents that have affected millions of hectares in North America in recent decades, implying significant impacts to the carbon (C) cycle. Here, we review and synthesize published studies of the effects of biotic disturbances on forest C cycling in the United States and Canada. Primary productivity in stands was reduced...

  18. Subsequent biotic crises delayed marine recovery following the late Permian mass extinction event in northern Italy.

    Directory of Open Access Journals (Sweden)

    William J Foster

    Full Text Available The late Permian mass extinction event was the largest biotic crisis of the Phanerozoic and has the longest recovery interval of any extinction event. It has been hypothesised that subsequent carbon isotope perturbations during the Early Triassic are associated with biotic crises that impeded benthic recovery. We test this hypothesis by undertaking the highest-resolution study yet made of the rock and fossil records of the entire Werfen Formation, Italy. Here, we show that elevated extinction rates were recorded not only in the Dienerian, as previously recognised, but also around the Smithian/Spathian boundary. Functional richness increases across the Smithian/Spathian boundary associated with elevated origination rates in the lower Spathian. The taxonomic and functional composition of benthic faunas only recorded two significant changes: (1 reduced heterogeneity in the Dienerian, and (2 and a faunal turnover across the Smithian/Spathian boundary. The elevated extinctions and compositional shifts in the Dienerian and across the Smithian/Spathian boundary are associated with a negative and positive isotope excursion, respectively, which supports the hypothesis that subsequent biotic crises are associated with carbon isotope shifts. The Spathian fauna represents a more advanced ecological state, not recognised in the previous members of the Werfen Formation, with increased habitat differentiation, a shift in the dominant modes of life, appearance of stenohaline taxa and the occupation of the erect and infaunal tiers. In addition to subsequent biotic crises delaying the recovery, therefore, persistent environmental stress limited the ecological complexity of benthic recovery prior to the Spathian.

  19. Biotic resistance: Exclusion of native rodent consumers releases populations of a weak invader

    Science.gov (United States)

    Dean E. Pearson; Teal Potter; John L. Maron

    2012-01-01

    Biotic resistance is a commonly invoked hypothesis to explain why most exotic plant species naturalize at low abundance. Although numerous studies have documented negative impacts of native consumers on exotic plant performance, longer-term multi-generation studies are needed to understand how native consumer damage to exotics translates to their population-level...

  20. Invasion by native tree species prevents biotic homogenization in novel forests of Puerto Rico

    Science.gov (United States)

    Oscar J. Abelleira Martinez

    2010-01-01

    There is concern that secondary forests dominated by introduced species, known as novel forests, increase taxonomical similarity between localities and lead to biotic homogenization in human dominated landscapes. In Puerto Rico, agricultural abandonment has given way to novel forests dominated by the introduced African tulip tree Spathodea campanulata Beauv. (...

  1. Utilizing genetic resources and precision agriculture to enhance resistance to biotic and abiotic stress in watermelon

    Science.gov (United States)

    Originally from Africa, watermelon is a staple crop in South Carolina and rich source of important phytochemicals that promote human health. As a result of many years of domestication and selection for desired fruit quality, modern watermelon cultivars are susceptible to biotic and abiotic stress. T...

  2. Climate, trees, pests, and weeds: Change, uncertainty, and biotic stressors in eastern US national park forests

    Science.gov (United States)

    Nicholas A. Fisichelli; Scott R. Abella; Matthew Peters; Frank J. Krist

    2014-01-01

    The US National Park Service (NPS) manages over 8900 km2 of forest area in the eastern United States where climate change and nonnative species are altering forest structure, composition, and processes. Understanding potential forest change in response to climate, differences in habitat projections among models (uncertainty), and nonnative biotic...

  3. Early biotic stress detection in tomato (Solanum lycopersicum) by BVOC emissions.

    Science.gov (United States)

    Kasal-Slavik, Tina; Eschweiler, Julia; Kleist, Einhard; Mumm, Roland; Goldbach, Heiner E; Schouten, Alexander; Wildt, Jürgen

    2017-12-01

    We investigated impacts of early and mild biotic stress on Biogenic Volatile Organic Compounds (BVOC) emissions from tomato in order to test their potential for early (biotic) stress detection. Tomato plants were exposed to two common fungal pathogens, Botrytis cinerea and Oidium neolycopesici and the sap-sucking aphid Myzus persicae. Furthermore, plants were exposed to methyl jasmonate (MeJA) in order to identify BVOC emissions related to activation of jasmonic acid (JA) signalling pathway. These emissions where then used as a reference for identifying active JA signalling pathway in plants at early stages of biotic stress. After infection by the necrotrophic fungus B. cinerea, changes in BVOC emissions indicated that tomato plants had predominantly activated the jasmonic acid (JA) signalling pathway. The plants were able to modify their defence pathways in order to overcome fungal infection. When tomato plants were infected with the biotrophic fungus O. neolycopersici, only minor changes in BVOC emissions were observed with additional emissions of the sesquiterpene α-copaene. α-copaene emissions allowed the identification of general biotic stress in the plants, without pinpointing the actual triggered defence pathway. BVOC emissions during M. persicae attack had changed before the occurrence of visual symptoms. Despite low infestation rates, plants emitted methyl salicylate indicating activation of the SA-mediated defence pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Abiotic and biotic drivers of biomass change in a Neotropical forest

    NARCIS (Netherlands)

    Sande, van der M.T.; Pena Claros, M.; Ascarrunz, Nataly; Arets, E.J.M.M.; Licona, J.C.; Toledo, Marisol; Poorter, L.

    2017-01-01

    Summary
    1. Tropical fores ts play an important role in the global carbon cycle, but the drivers of net forest biomass change (i.e. net carbon sequestration) are poorly understood. Here, we evaluate how abiotic factors (soil co nditions and disturbance) and biotic factors (forest structure,

  5. Biotic and abiotic oxidation and reduction of iron at circumneutral pH are inseparable processes under natural conditions

    NARCIS (Netherlands)

    Ionescu, Danny; Heim, Christine; Polerecky, L.; Thiel, Volker; de Beer, Dirk

    2015-01-01

    Oxidation and reduction of iron can occur through abiotic (chemical) and biotic (microbial) processes. Abiotic iron oxidation is a function of pH and O2 concentration. Biotic iron oxidation is carried out by a diverse group of bacteria, using O2 or NO3 as terminal electron acceptors. At

  6. Linking biotic homogenization to habitat type, invasiveness and growth form of naturalized alien plants in North America

    Science.gov (United States)

    Hong Qian; Qinfeng. Guo

    2010-01-01

    Aim Biotic homogenization is a growing phenomenon and has recently attracted much attention. Here, we analyse a large dataset of native and alien plants in North America to examine whether biotic homogenization is related to several ecological and biological attributes. Location North America (north of Mexico). Methods We assembled...

  7. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    R. S. Nowak; J. Arnone; L. Fenstermaker; and S. D. Smith

    2005-07-26

    This project provided the funding to operate and maintain the Nevada Desert FACE Facility. This support funds the CO{sub 2}, system repairs and maintenance, basic physical and biological site information, and personnel that are essential for the experiment to continue. They have continued to assess the effects of elevated CO{sub 2} on three key processes: (1) leaf- to plant-level responses of desert vegetation to elevated atmospheric CO{sub 2}; (2) ecosystem-level responses; and (3) integration of plant and ecosystem processes to understand carbon balance of deserts. The focus is the seminal interactions among atmospheric CO{sub 2}, water, and nitrogen that drive desert responses to elevated CO{sub 2} and explicitly address processes that occur across scales (biological, spatial, and temporal).

  8. An evaluation of biotic ligand models predicting acute copper toxicity to Daphnia magna in wastewater effluent.

    Science.gov (United States)

    Constantino, Carlos; Scrimshaw, Mark; Comber, Sean; Churchley, John

    2011-04-01

    The toxicity of Cu to Daphnia magna was investigated in a series of 48-h immobilization assays in effluents from four wastewater treatment works. The assay results were compared with median effective concentration (EC50) forecasts produced by the HydroQual biotic ligand model (BLM), the refined D. magna BLM, and a modified BLM that was constructed by integrating the refined D. magna biotic ligand characterization with the Windermere humic aqueous model (WHAM) VI geochemical speciation model, which also accommodated additional effluent characteristics as model inputs. The results demonstrated that all the BLMs were capable of predicting toxicity by within a factor of two, and that the modified BLM produced the most accurate toxicity forecasts. The refined D. magna BLM offered the most robust assessment of toxicity in that it was not reliant on the inclusion of effluent characteristics or optimization of the dissolved organic carbon active fraction to produce forecasts that were accurate by within a factor of two. The results also suggested that the biotic ligand stability constant for Na may be a poor approximation of the mechanisms governing the influence of Na where concentrations exceed the range within which the biotic ligand stability constant value had been determined. These findings support the use of BLMs for the establishment of site-specific water quality standards in waters that contain a substantial amount of wastewater effluent, but reinforces the need for regulators to scrutinize the composition of models, their thermodynamic and biotic ligand parameters, and the limitations of those parameters. Copyright © 2011 SETAC.

  9. Identification of Arabidopsis candidate genes in response to biotic and abiotic stresses using comparative microarrays.

    Directory of Open Access Journals (Sweden)

    Arjun Sham

    Full Text Available Plants have evolved with intricate mechanisms to cope with multiple environmental stresses. To adapt with biotic and abiotic stresses, plant responses involve changes at the cellular and molecular levels. The current study was designed to investigate the effects of combinations of different environmental stresses on the transcriptome level of Arabidopsis genome using public microarray databases. We investigated the role of cyclopentenones in mediating plant responses to environmental stress through TGA (TGACG motif-binding factor transcription factor, independently from jasmonic acid. Candidate genes were identified by comparing plants inoculated with Botrytis cinerea or treated with heat, salt or osmotic stress with non-inoculated or non-treated tissues. About 2.5% heat-, 19% salinity- and 41% osmotic stress-induced genes were commonly upregulated by B. cinerea-treatment; and 7.6%, 19% and 48% of genes were commonly downregulated by B. cinerea-treatment, respectively. Our results indicate that plant responses to biotic and abiotic stresses are mediated by several common regulatory genes. Comparisons between transcriptome data from Arabidopsis stressed-plants support our hypothesis that some molecular and biological processes involved in biotic and abiotic stress response are conserved. Thirteen of the common regulated genes to abiotic and biotic stresses were studied in detail to determine their role in plant resistance to B. cinerea. Moreover, a T-DNA insertion mutant of the Responsive to Dehydration gene (rd20, encoding for a member of the caleosin (lipid surface protein family, showed an enhanced sensitivity to B. cinerea infection and drought. Overall, the overlapping of plant responses to abiotic and biotic stresses, coupled with the sensitivity of the rd20 mutant, may provide new interesting programs for increased plant resistance to multiple environmental stresses, and ultimately increases its chances to survive. Future research

  10. Identification of Arabidopsis candidate genes in response to biotic and abiotic stresses using comparative microarrays.

    Science.gov (United States)

    Sham, Arjun; Moustafa, Khaled; Al-Ameri, Salma; Al-Azzawi, Ahmed; Iratni, Rabah; AbuQamar, Synan

    2015-01-01

    Plants have evolved with intricate mechanisms to cope with multiple environmental stresses. To adapt with biotic and abiotic stresses, plant responses involve changes at the cellular and molecular levels. The current study was designed to investigate the effects of combinations of different environmental stresses on the transcriptome level of Arabidopsis genome using public microarray databases. We investigated the role of cyclopentenones in mediating plant responses to environmental stress through TGA (TGACG motif-binding factor) transcription factor, independently from jasmonic acid. Candidate genes were identified by comparing plants inoculated with Botrytis cinerea or treated with heat, salt or osmotic stress with non-inoculated or non-treated tissues. About 2.5% heat-, 19% salinity- and 41% osmotic stress-induced genes were commonly upregulated by B. cinerea-treatment; and 7.6%, 19% and 48% of genes were commonly downregulated by B. cinerea-treatment, respectively. Our results indicate that plant responses to biotic and abiotic stresses are mediated by several common regulatory genes. Comparisons between transcriptome data from Arabidopsis stressed-plants support our hypothesis that some molecular and biological processes involved in biotic and abiotic stress response are conserved. Thirteen of the common regulated genes to abiotic and biotic stresses were studied in detail to determine their role in plant resistance to B. cinerea. Moreover, a T-DNA insertion mutant of the Responsive to Dehydration gene (rd20), encoding for a member of the caleosin (lipid surface protein) family, showed an enhanced sensitivity to B. cinerea infection and drought. Overall, the overlapping of plant responses to abiotic and biotic stresses, coupled with the sensitivity of the rd20 mutant, may provide new interesting programs for increased plant resistance to multiple environmental stresses, and ultimately increases its chances to survive. Future research directions towards a

  11. Impact of Combined Abiotic and Biotic Stresses on Plant Growth and Avenues for Crop Improvement by Exploiting Physio-morphological Traits.

    Science.gov (United States)

    Pandey, Prachi; Irulappan, Vadivelmurugan; Bagavathiannan, Muthukumar V; Senthil-Kumar, Muthappa

    2017-01-01

    Global warming leads to the concurrence of a number of abiotic and biotic stresses, thus affecting agricultural productivity. Occurrence of abiotic stresses can alter plant-pest interactions by enhancing host plant susceptibility to pathogenic organisms, insects, and by reducing competitive ability with weeds. On the contrary, some pests may alter plant response to abiotic stress factors. Therefore, systematic studies are pivotal to understand the effect of concurrent abiotic and biotic stress conditions on crop productivity. However, to date, a collective database on the occurrence of various stress combinations in agriculturally prominent areas is not available. This review attempts to assemble published information on this topic, with a particular focus on the impact of combined drought and pathogen stresses on crop productivity. In doing so, this review highlights some agriculturally important morpho-physiological traits that can be utilized to identify genotypes with combined stress tolerance. In addition, this review outlines potential role of recent genomic tools in deciphering combined stress tolerance in plants. This review will, therefore, be helpful for agronomists and field pathologists in assessing the impact of the interactions between drought and plant-pathogens on crop performance. Further, the review will be helpful for physiologists and molecular biologists to design agronomically relevant strategies for the development of broad spectrum stress tolerant crops.

  12. Impact of Combined Abiotic and Biotic Stresses on Plant Growth and Avenues for Crop Improvement by Exploiting Physio-morphological Traits

    Science.gov (United States)

    Pandey, Prachi; Irulappan, Vadivelmurugan; Bagavathiannan, Muthukumar V.; Senthil-Kumar, Muthappa

    2017-01-01

    Global warming leads to the concurrence of a number of abiotic and biotic stresses, thus affecting agricultural productivity. Occurrence of abiotic stresses can alter plant–pest interactions by enhancing host plant susceptibility to pathogenic organisms, insects, and by reducing competitive ability with weeds. On the contrary, some pests may alter plant response to abiotic stress factors. Therefore, systematic studies are pivotal to understand the effect of concurrent abiotic and biotic stress conditions on crop productivity. However, to date, a collective database on the occurrence of various stress combinations in agriculturally prominent areas is not available. This review attempts to assemble published information on this topic, with a particular focus on the impact of combined drought and pathogen stresses on crop productivity. In doing so, this review highlights some agriculturally important morpho-physiological traits that can be utilized to identify genotypes with combined stress tolerance. In addition, this review outlines potential role of recent genomic tools in deciphering combined stress tolerance in plants. This review will, therefore, be helpful for agronomists and field pathologists in assessing the impact of the interactions between drought and plant-pathogens on crop performance. Further, the review will be helpful for physiologists and molecular biologists to design agronomically relevant strategies for the development of broad spectrum stress tolerant crops. PMID:28458674

  13. Coupled biotic-abiotic oxidation of organic matter by biogenic MnO_{2}

    Science.gov (United States)

    Gonzalez, Julia; Peña, Jasquelin

    2016-04-01

    Some reactive soil minerals are strongly implicated in stabilising organic matter. However, others can play an active role in the oxidation of organic molecules. In natural systems, layer-type manganese oxide minerals (MnO2) typically occur as biomineral assemblages consisting of mineral particles and microbial biomass. Both the mineral and biological fractions of the assemblage can be powerful oxidants of organic C. The biological compartment relies on a set of enzymes to drive oxidative transformations of reduced C-substrates, whereas MnO2 minerals are strong, less specific abiotic oxidants that are assumed to rely on interfacial interactions between C-substrates and the mineral surface. This project aims to understand the coupling between microbial C mineralization and abiotic C oxidation mediated by MnO2 in bacterial-MnO2 assemblages. Specifically, under conditions of high C turnover, microbial respiration can significantly alter local pH, dissolved oxygen and pool of available reductants, which may modify rates and mechanism of C oxidation by biotic and abiotic components. We first investigated changes in the solution chemistry of Pseudomonas putida suspensions exposed to varying concentrations of glucose, chosen to represent readily bioavailable substrates in soils. Glucose concentrations tested ranged between 0 and 5.5mM and changes in pH, dissolved oxygen and dissolved organic and inorganic carbon were tracked over 48h. We then combined literature review and wet-chemical experiments to compile the pH dependence of rates of organic substrate oxidation by MnO2, including glucose. Our results demonstrate a strong pH dependence for these abiotic reactions. In assemblages of P. putida - MnO2, kinetic limitations for abiotic C oxidation by MnO2 are overcome by changes in biogeochemical conditions that result from bacterial C metabolism. When extrapolated to a soil solution confronted to an input of fresh dissolved organic matter, bacterial C metabolism of the

  14. Biotic and Climatic Velocity Identify Contrasting Areas of Vulnerability to Climate Change.

    Directory of Open Access Journals (Sweden)

    Carlos Carroll

    Full Text Available Metrics that synthesize the complex effects of climate change are essential tools for mapping future threats to biodiversity and predicting which species are likely to adapt in place to new climatic conditions, disperse and establish in areas with newly suitable climate, or face the prospect of extirpation. The most commonly used of such metrics is the velocity of climate change, which estimates the speed at which species must migrate over the earth's surface to maintain constant climatic conditions. However, "analog-based" velocities, which represent the actual distance to where analogous climates will be found in the future, may provide contrasting results to the more common form of velocity based on local climate gradients. Additionally, whereas climatic velocity reflects the exposure of organisms to climate change, resultant biotic effects are dependent on the sensitivity of individual species as reflected in part by their climatic niche width. This has motivated development of biotic velocity, a metric which uses data on projected species range shifts to estimate the velocity at which species must move to track their climatic niche. We calculated climatic and biotic velocity for the Western Hemisphere for 1961-2100, and applied the results to example ecological and conservation planning questions, to demonstrate the potential of such analog-based metrics to provide information on broad-scale patterns of exposure and sensitivity. Geographic patterns of biotic velocity for 2954 species of birds, mammals, and amphibians differed from climatic velocity in north temperate and boreal regions. However, both biotic and climatic velocities were greatest at low latitudes, implying that threats to equatorial species arise from both the future magnitude of climatic velocities and the narrow climatic tolerances of species in these regions, which currently experience low seasonal and interannual climatic variability. Biotic and climatic velocity, by

  15. Biotic and Climatic Velocity Identify Contrasting Areas of Vulnerability to Climate Change

    Science.gov (United States)

    Carroll, Carlos; Lawler, Joshua J.; Roberts, David R.; Hamann, Andreas

    2015-01-01

    Metrics that synthesize the complex effects of climate change are essential tools for mapping future threats to biodiversity and predicting which species are likely to adapt in place to new climatic conditions, disperse and establish in areas with newly suitable climate, or face the prospect of extirpation. The most commonly used of such metrics is the velocity of climate change, which estimates the speed at which species must migrate over the earth’s surface to maintain constant climatic conditions. However, “analog-based” velocities, which represent the actual distance to where analogous climates will be found in the future, may provide contrasting results to the more common form of velocity based on local climate gradients. Additionally, whereas climatic velocity reflects the exposure of organisms to climate change, resultant biotic effects are dependent on the sensitivity of individual species as reflected in part by their climatic niche width. This has motivated development of biotic velocity, a metric which uses data on projected species range shifts to estimate the velocity at which species must move to track their climatic niche. We calculated climatic and biotic velocity for the Western Hemisphere for 1961–2100, and applied the results to example ecological and conservation planning questions, to demonstrate the potential of such analog-based metrics to provide information on broad-scale patterns of exposure and sensitivity. Geographic patterns of biotic velocity for 2954 species of birds, mammals, and amphibians differed from climatic velocity in north temperate and boreal regions. However, both biotic and climatic velocities were greatest at low latitudes, implying that threats to equatorial species arise from both the future magnitude of climatic velocities and the narrow climatic tolerances of species in these regions, which currently experience low seasonal and interannual climatic variability. Biotic and climatic velocity, by approximating

  16. Biotic pump of atmospheric moisture as driver of the hydrological cycle on land

    Directory of Open Access Journals (Sweden)

    A. M. Makarieva

    2007-01-01

    Full Text Available In this paper the basic geophysical and ecological principles are jointly analyzed that allow the landmasses of Earth to remain moistened sufficiently for terrestrial life to be possible. 1. Under gravity, land inevitably loses water to the ocean. To keep land moistened, the gravitational water runoff must be continuously compensated by the atmospheric ocean-to-land moisture transport. Using data for five terrestrial transects of the International Geosphere Biosphere Program we show that the mean distance to which air fluxes can transport moisture over non-forested areas, does not exceed several hundred kilometers; precipitation decreases exponentially with distance from the ocean. 2. In contrast, precipitation over extensive natural forests does not depend on the distance from the ocean along several thousand kilometers, as illustrated for the Amazon and Yenisey river basins and Equatorial Africa. This points to the existence of an active biotic pump transporting atmospheric moisture inland from the ocean. 3. Physical principles of the biotic moisture pump are investigated based on the previously unstudied properties of atmospheric water vapor, which can be either in or out of aerostatic equilibrium depending on the lapse rate of air temperature. A novel physical principle is formulated according to which the low-level air moves from areas with weak evaporation to areas with more intensive evaporation. Due to the high leaf area index, natural forests maintain high evaporation fluxes, which support the ascending air motion over the forest and "suck in" moist air from the ocean, which is the essence of the biotic pump of atmospheric moisture. In the result, the gravitational runoff water losses from the optimally moistened forest soil can be fully compensated by the biotically enhanced precipitation at any distance from the ocean. 4. It is discussed how a continent-scale biotic water pump mechanism could be produced by natural selection acting on

  17. Stable carbon isotope analysis to distinguish biotic and abiotic degradation of 1,1,1-trichloroethane in groundwater sediments

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Hunkeler, Daniel; Tuxen, Nina

    2014-01-01

    The fate and treatability of 1,1,1-TCA by natural and enhanced reductive dechlorination was studied in laboratory microcosms. The study shows that compound-specific isotope analysis (CSIA) identified an alternative 1,1,1-TCA degradation pathway that cannot be explained by assuming biotic reductive...... dechlorination. In all biotic microcosms 1,1,1-TCA was degraded with no apparent increase in the biotic degradation product 1,1-DCA. 1,1,1-TCA degradation was documented by a clear enrichment in 13C in all biotic microcosms, but not in the abiotic control, which suggests biotic or biotically mediated degradation....... Biotic degradation by reductive dechlorination of 1,1-DCA to CA only occurred in bioaugmented microcosms and in donor stimulated microcosms with low initial 1,1,1-TCA or after significant decrease in 1,1,1-TCA concentration (after ∼day 200). Hence, the primary degradation pathway for 1,1,1-TCA does...

  18. Multi-regional synthesis of temporal trends in biotic assemblages in streams and rivers of the continental United States

    Science.gov (United States)

    Miller, Matthew P.; Brasher, Anne M.D.; Keenen, Jonathan G.

    2013-01-01

    Biotic assemblages in aquatic ecosystems are excellent integrators and indicators of changing environmental conditions within a watershed. Therefore, temporal changes in abiotic environmental variables often can be inferred from temporal changes in biotic assemblages. Algae, macroinvertebrate, and fish assemblage data were collected from 91 sampling sites in 4 geographic regions (northeastern/north-central, southeastern, south-central, and western), collectively encompassing the continental United States, from 1993 to 2009 as part of the U.S. Geological Survey National Water-Quality Assessment Program. This report uses a multivariate approach to synthesize temporal trends in biotic assemblages and correlations with relevant abiotic parameters as a function of biotic assemblage, geographic region, and land use. Of the three groups of biota, algal assemblages had temporal trends at the greatest percentage of sites. Of the regions, a greater percentage of sites in the northeastern/north-central and western regions had temporal trends in biotic assemblages. In terms of land use, a greater percentage of watersheds draining agricultural, urban, and undeveloped areas had significant temporal changes in biota, as compared to watersheds with mixed use. Correlations between biotic assemblages and abiotic variables indicate that, in general, macroinvertebrate assemblages correlated with water quality and fish assemblages correlated with physical habitat. Taken together, results indicate that there are regional differences in how individual biotic assemblages (algae, macroinvertebrates, and fish) respond to different abiotic drivers of change.

  19. Assessing the Availability of Terrestrial Biotic Materials in Product Systems (BIRD

    Directory of Open Access Journals (Sweden)

    Vanessa Bach

    2017-01-01

    Full Text Available Availability of abiotic resources has been a topic of concern in recent years, resulting in several approaches being published to determine their availability on country and product level. However, the availability of biotic materials has not been analyzed to this extent yet. Therefore, an approach to determine possible limitations to availability of terrestrial biotic materials over the entire supply chain is introduced. The approach considers 24 categories overall as well as associated category indicators for the five dimensions: physical, socio-economic, abiotic, social and environmental constraints. This ensures a comprehensive availability assessment of bio-based product systems. The approach is applied to a case study comparing biodiesel produced from rapeseed and soy beans. The study shows that the determination of indicator values is feasible for most categories and their interpretation leads to meaningful conclusions. Thus, the approach leads to a more comprehensive assessment of availability aspects and supports better informed decision making in industry and policy.

  20. Relationships Between Plankton Primary Productivity, Biotic and Abiotic Variables of Carp Fish Ponds

    Directory of Open Access Journals (Sweden)

    Doychin I. Terziyski

    2016-12-01

    Full Text Available Experiments measuring primary productivity, biotic and abiotic environmental factors in carp ponds were carried out within three consecutive years (2004, 2005 and 2006. The aim of the study was investigation of the relations between the biotic and abiotic variables, their influence on the primary productivity and the effect of manuring on the fish ponds. The influence of environmental factors onto primary productivity was investigated in ponds with and without organic manure. Nitrate nitrogen demonstrated the closest relationship with the gross primary productivity followed by chlorophyll a level and N/P ratio in manured ponds. When no manuring was applied, the importance of the nutrients along the food chain: nutrients– phytoplankton – zooplankton decreased. Trends, which can be used for increasing of productivity in carp ponds, were obtained. They give indications to improve the existing practices for better management of production efficiency and water quality in fish farms.

  1. Evolution and Adaptation of Wild Emmer Wheat Populations to Biotic and Abiotic Stresses.

    Science.gov (United States)

    Huang, Lin; Raats, Dina; Sela, Hanan; Klymiuk, Valentina; Lidzbarsky, Gabriel; Feng, Lihua; Krugman, Tamar; Fahima, Tzion

    2016-08-04

    The genetic bottlenecks associated with plant domestication and subsequent selection in man-made agroecosystems have limited the genetic diversity of modern crops and increased their vulnerability to environmental stresses. Wild emmer wheat, the tetraploid progenitor of domesticated wheat, distributed along a wide range of ecogeographical conditions in the Fertile Crescent, has valuable "left behind" adaptive diversity to multiple diseases and environmental stresses. The biotic and abiotic stress responses are conferred by series of genes and quantitative trait loci (QTLs) that control complex resistance pathways. The study of genetic diversity, genomic organization, expression profiles, protein structure and function of biotic and abiotic stress-resistance genes, and QTLs could shed light on the evolutionary history and adaptation mechanisms of wild emmer populations for their natural habitats. The continuous evolution and adaptation of wild emmer to the changing environment provide novel solutions that can contribute to safeguarding food for the rapidly growing human population.

  2. A biotic game design project for integrated life science and engineering education.

    Directory of Open Access Journals (Sweden)

    Nate J Cira

    2015-03-01

    Full Text Available Engaging, hands-on design experiences are key for formal and informal Science, Technology, Engineering, and Mathematics (STEM education. Robotic and video game design challenges have been particularly effective in stimulating student interest, but equivalent experiences for the life sciences are not as developed. Here we present the concept of a "biotic game design project" to motivate student learning at the interface of life sciences and device engineering (as part of a cornerstone bioengineering devices course. We provide all course material and also present efforts in adapting the project's complexity to serve other time frames, age groups, learning focuses, and budgets. Students self-reported that they found the biotic game project fun and motivating, resulting in increased effort. Hence this type of design project could generate excitement and educational impact similar to robotics and video games.

  3. A biotic game design project for integrated life science and engineering education.

    Science.gov (United States)

    Cira, Nate J; Chung, Alice M; Denisin, Aleksandra K; Rensi, Stefano; Sanchez, Gabriel N; Quake, Stephen R; Riedel-Kruse, Ingmar H

    2015-03-01

    Engaging, hands-on design experiences are key for formal and informal Science, Technology, Engineering, and Mathematics (STEM) education. Robotic and video game design challenges have been particularly effective in stimulating student interest, but equivalent experiences for the life sciences are not as developed. Here we present the concept of a "biotic game design project" to motivate student learning at the interface of life sciences and device engineering (as part of a cornerstone bioengineering devices course). We provide all course material and also present efforts in adapting the project's complexity to serve other time frames, age groups, learning focuses, and budgets. Students self-reported that they found the biotic game project fun and motivating, resulting in increased effort. Hence this type of design project could generate excitement and educational impact similar to robotics and video games.

  4. Characterization and comparison of iron oxyhydroxide precipitates from biotic and abiotic groundwater treatments

    DEFF Research Database (Denmark)

    Arturi, Katarzyna R.; Bender Koch, Christian; Søgaard, Erik G.

    2017-01-01

    Removal of iron is an important step in groundwater treatment for drinking water production. It is performed to prevent organoleptic issues and clogging in water supply systems. Iron can be eliminated with a purely physico-chemical (abiotic) method or biotically with the help of iron......-oxidizing bacteria (FeOB). Each of the purification methods requires different operating conditions and results in formation of iron oxyhydroxide (FeOOH) precipitates. Knowledge about the differences in composition and properties of the biotic and abiotic precipitates is desirable from a technical, but also...... scientific point of view. In this study, a broad spectrum of analytical methods was employed to describe in detail the differences between FeOOH produced in a number of Danish waterworks using either the purely physico-chemical or the biological variation of the iron removal method. According to the results...

  5. Effects of native biodiversity on grape loss of four castes: testing the biotic resistance hypothesis

    Directory of Open Access Journals (Sweden)

    M. Nereu

    2018-02-01

    Full Text Available Management of agricultural landscapes can influence the biodiversity and the ecological services provided by these ecosystems, such as natural biological pest control. Viticulture is a very important economic activity in most countries with Mediterranean climate, often shaping their landscapes and culture. Grape production is affected by a number of pests and diseases, and farmers use prophylactic and response-driven pesticides to control these pests. Here we quantified the main biotic causes of crop losses in four grape castes, two red (Touriga Nacional and Baga and two white (Arinto and Chardonnay, and evaluated the potential effect of native biodiversity to provide biotic resistance to pest outbreaks and grape losses. Specifically, the diversity and abundance of bird and insect communities in these vineyards were quantified and divided into functional guilds (pest, neutral or auxiliary, to test whether these natural communities hold the potential to naturally control grape pests (biotic resistance hypothesis under normal vineyard management (including pesticide application regimes. A potential association between distance to the vineyard edge and grape losses was also evaluated. We recorded a very small proportion of grape losses (mean  =  0.6 %; max  =  7.5 %, with insect pests showing a preference for the castes Baga (red and Chardonnay (white, while bird pests avoided the caste Arinto (white. Grape color did not influence losses caused by insect pests, but birds showed a preference for red castes. The caste Baga was also more vulnerable to losses caused by fungi. Despite their low impact on grape production, most insects and birds detected in the six vineyards were pests, which entails a potentially low level of biotic resistance in this highly managed agricultural ecosystem. Further research is necessary to fully evaluate the role of functional biodiversity in vineyards, particularly if alternative production processes

  6. Transcriptomic responses to biotic stresses in Malus x domestica: a meta-analysis study

    OpenAIRE

    Balan, Bipin; Marra, Francesco Paolo; Caruso, Tiziano; Martinelli, Federico

    2018-01-01

    RNA-Seq analysis is a strong tool to gain insight into the molecular responses to biotic stresses in plants. The objective of this work is to identify specific and common molecular responses between different transcriptomic data related to fungi, virus and bacteria attacks in Malus x domestica. We analyzed seven transcriptomic datasets in Malus x domestica divided in responses to fungal pathogens, virus (Apple Stem Grooving Virus) and bacteria (Erwinia amylovora). Data were dissected using an...

  7. Effects of biotic disturbances on forest carbon cycling in the United States and Canada

    Science.gov (United States)

    Vogelmann, James E.; Allen, Craig D.; Hicke, Jeffrey A.; Desai, Ankur R.; Dietze, Michael C.; Hall, Ronald J.; ,

    2012-01-01

    Forest insects and pathogens are major disturbance agents that have affected millions of hectares in North America in recent decades, implying significant impacts to the carbon (C) cycle. Here, we review and synthesize published studies of the effects of biotic disturbances on forest C cycling in the United States and Canada. Primary productivity in stands was reduced, sometimes considerably, immediately following insect or pathogen attack. After repeated growth reductions caused by some insects or pathogens or a single infestation by some bark beetle species, tree mortality occurred, altering productivity and decomposition. In the years following disturbance, primary productivity in some cases increased rapidly as a result of enhanced growth by surviving vegetation, and in other cases increased slowly because of lower forest regrowth. In the decades following tree mortality, decomposition increased as a result of the large amount of dead organic matter. Net ecosystem productivity decreased immediately following attack, with some studies reporting a switch to a C source to the atmosphere, and increased afterward as the forest regrew and dead organic matter decomposed. Large variability in C cycle responses arose from several factors, including type of insect or pathogen, time since disturbance, number of trees affected, and capacity of remaining vegetation to increase growth rates following outbreak. We identified significant knowledge gaps, including limited understanding of carbon cycle impacts among different biotic disturbance types (particularly pathogens), their impacts at landscape and regional scales, and limited capacity to predict disturbance events and their consequences for carbon cycling. We conclude that biotic disturbances can have major impacts on forest C stocks and fluxes and can be large enough to affect regional C cycling. However, additional research is needed to reduce the uncertainties associated with quantifying biotic disturbance effects on

  8. Biotic and abiotic stress-induced phenylpropanoids in leaves of the mango (Mangifera indica L., Anacardiaceae)

    OpenAIRE

    Silva, Rodolfo R. da; Câmara, Cláudio A. G. da; Almeida, Argus V.; Ramos, Clécio S.

    2012-01-01

    It is now widely recognized that plant’s chemical composition is affected by both abiotic and biotic stress. This is the case of Mangifera indica leaves which respond very clearly to the damages caused by the grasshopper Tropidacris collaris and to mechanical damage by biosynthesizing several stress-related volatile compounds, mainly phenylpropanoids such as myristicin, dillapiole, eugenol and eugenol acetate. The identification of these phenylpropanoids in mango leaves in response to abiotic...

  9. Importance of biotic and abiotic components in feedback between plants and soil

    OpenAIRE

    Hanzelková, Věra

    2017-01-01

    The plant-soil feedback affects the forming of a plant community. Plants affect their own species as well as other species. The plant-soil feedback can be both positive and negative. Plants affect soil, change its properties, and the soil affects the plants reciprocally. Soil components can be divided into biotic and abiotic ones. The abiotic component is represented by physical and chemical properties of the soil. The main properties are the soil structure, the soil moisture, the soil temper...

  10. Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

    OpenAIRE

    Xing Wang; Binghui Zheng; Lusan Liu; Lijing Wang

    2015-01-01

    A Lake Multi-biotic Integrity Index (LMII) for the China’s second largest interior lake (Dongting Lake) was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diato...

  11. Benefits of Biotic Pollination for Non-Timber Forest Products and Cultivated Plants

    Directory of Open Access Journals (Sweden)

    Rehel Shiny

    2009-01-01

    Full Text Available Biodiversity supplies multiple goods and services to society and is critical for the support of livelihoods across the globe. Many indigenous people depend upon non-timber forest products (NTFP and crops for a range of goods including food, medicine, fibre and construction materials. However, the dependency of these products on biotic pollination services is poorly understood. We used the biologically and culturally diverse Nilgiri Biosphere Reserve in India to characterise the types of NTFP and crop products of 213 plant species and asses their degree of dependency on animal pollination. We found that 80 per cent of all species benefited from animal pollination in their reproduction, and that 62 per cent of crop products and 40 per cent of NTFP benefited from biotic pollination in their production. Further we identified the likely pollinating taxa documented as responsible for the production of these products, mainly bees and other insects. A lower proportion of indigenous plant products (39 per cent benefited from biotic pollination than products from introduced plants (61 per cent. We conclude that pollinators play an important role in the livelihoods of people in this region.

  12. [Predicting copper toxicity to Hypophthalmichthys molitrix and Ctenopharyngodon idellus based on biotic ligand model].

    Science.gov (United States)

    Wang, Wan-Bin; Chen, Sha; Wu, Min; Zhao, Jing

    2014-10-01

    A series of 96 h copper acute toxicity experiments were conducted with Ctenopharyngodon idellus and Hypophthalmichthys molitrix under different concentrations of DOC [ρ(DOC) 0.05, 0.5, 1, 2, 4 mg · L(-1)]. Higher DOC resulted in a reduction of toxicity, which was in line with the concepts of the biotic ligand model (BLM). It was concluded that the mean absolute deviation (MAD) of LC50 with Ctenopharyngodon idellus and Hypophthalmichthys molitrix was 591.2, 157.14 μg · L(-1) and 728.18, 91.24 μg x L(-1), respectively, by the prediction of copper BLM developed for Fathead minnow and Rainbow trout. Based on speciation analysis of biotic ligand model, it was shown that LA50 values of Ctenopharyngodon idellus and Hypophthalmichthys molitrix were 10.960 and 3.978 nmol · g(-1), respectively. Then the MAD values became 280.52 and 92.25 μg · L(-1) for Ctenopharyngodon idellus and Hypophthalmichthys molitrix using the normalized LA50. Finally by searching toxicity data in literature, the MAD values on Ctenopharyngodon idellus and Hypophthalmichthys molitrix were 252.37 and 50.26 μg · L(-1), successively. This result verified that the toxicity prediction based on biotic ligand model was practical.

  13. The application of biotic elicitor on Artemisia annua L. to increase artemisinin content

    Science.gov (United States)

    Darwati, I.; Manohara, D.; Rohimatun; Nurhayati, H.

    2018-01-01

    Artemisinin-based Combination Therapy (ACT) has been recommended by WHO as an alternative to treat malaria overcoming drug resistance. The secondary metabolic products in plants, including artemisinin, can be increased by utilizing biotic elicitor from fungi. The research was conducted in Gunung Putri Research Installation, Cipanas, West Java from 2010 to 2011. Phytophthora sp. from eggplant and Colletotrichum sp. from Artemisia annua were applied as biotic elicitor. The types of biotic elicitor applied to the plants were 1) the medium of potato dextrose broth were inoculated with fungi and harvested after 10 days (filtrate), 2) powdery mycelium of both fungi. There were 16 treatments: control negative, control positive (uninoculated medium) 1%, 2%, 3% (v/v)], Phytophthora sp. filtrate [1, 2% and 3% (v/v)], Colletotrichum sp. filtrate [1, 2% and 3% (v/v)], Phytophthora sp. mycelium [1%, 2% and 3% (w/v)], Colletotrichum sp mycelium [1%, 2% and 3% (w/v)]. The elicitor application increased plant production by 26.21% and artemisinin yield by 72% compared to control. Furthermore, the artemisinin production of the plants treated with medium inoculated with 2% filtrate of Phytophthora sp (FP2) (25.19 kg/ha) and 1% powdery mycelium of Colletotrichum sp (MC1) (26.42 kg/ha) were higher than control (K) (11.17 kg/ha).

  14. Comparative study of the corrosion product films formed in biotic and abiotic media

    Energy Technology Data Exchange (ETDEWEB)

    Videla, H.A.; Mele, M.F.L. de [Univ. of La Plata (Argentina). Dept. of Chemistry; Swords, C. [Univ. of Leeds (United Kingdom). School of Materials; Edyvean, R.G.J. [Univ. of Sheffield (United Kingdom). Dept. of Chemical and Processing Engineering; Beech, I.B. [Univ. of Portsmouth (United Kingdom). Dept. of Chemistry

    1999-11-01

    The growth of sulfate-reducing bacteria (SRB) affects several important parameters at the metal/solution interface of carbon steel in liquid media such as pH and redox potential values, as well as modifications of the composition and structure of corrosion product layers. Electrochemical techniques for corrosion assessment and surface analyses by energy dispersion X-ray analysis (EDAX), X-ray photoelectron spectra (XPS), X-ray distraction (XRD) and electron microprobe analysis (EPMA) complemented with scanning electron microscopy (SEM) and atomic force microscopy (MM) observations, were used to study the structure and composition of protective films on carbon steel in abiotic and biotic media containing different sulfur anions. The results revealed that in biotic and abiotic sulfide films the outer layers were formed by both FeS and FeS{sub 2}, although the relative content of these compounds varied in each case. Usually, the corrosion product films biotically formed were more adherent to the metal surface than those developed abiotically. The latter were flaky and loosely adherent, thus differing in their function during the corrosion process.

  15. Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors.

    Science.gov (United States)

    Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

    2015-07-28

    Host-parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors.

  16. Taxonomic scale-dependence of habitat niche partitioning and biotic neighbourhood on survival of tropical tree seedlings.

    Science.gov (United States)

    Queenborough, Simon A; Burslem, David F R P; Garwood, Nancy C; Valencia, Renato

    2009-12-07

    In order to differentiate between mechanisms of species coexistence, we examined the relative importance of local biotic neighbourhood, abiotic habitat factors and species differences as factors influencing the survival of 2330 spatially mapped tropical tree seedlings of 15 species of Myristicaceae in two separate analyses in which individuals were identified first to species and then to genus. Using likelihood methods, we selected the most parsimonious candidate models as predictors of 3 year seedling survival in both sets of analyses. We found evidence for differential effects of abiotic niche and neighbourhood processes on individual survival between analyses at the genus and species levels. Niche partitioning (defined as an interaction of taxonomic identity and abiotic neighbourhood) was significant in analyses at the genus level, but did not differentiate among species in models of individual seedling survival. By contrast, conspecific and congeneric seedling and adult density were retained in the minimum adequate models of seedling survival at species and genus levels, respectively. We conclude that abiotic niche effects express differences in seedling survival among genera but not among species, and that, within genera, community and/or local variation in adult and seedling abundance drives variation in seedling survival. These data suggest that different mechanisms of coexistence among tropical tree taxa may function at different taxonomic or phylogenetic scales. This perspective helps to reconcile perceived differences of importance in the various non-mutually exclusive mechanisms of species coexistence in hyper-diverse tropical forests.

  17. Assessment of Relationships between Earthworms and Soil Abiotic and Biotic Factors as a Tool in Sustainable Agricultural

    Directory of Open Access Journals (Sweden)

    Radoslava Kanianska

    2016-09-01

    Full Text Available Earthworms are a major component of soil fauna communities. They influence soil chemical, biological, and physical processes and vice versa, their abundance and diversity are influenced by natural characteristics or land management practices. There is need to establish their characteristics and relations. In this study earthworm density (ED, body biomass (EB, and diversity in relation to land use (arable land—AL, permanent grasslands—PG, management, and selected abiotic (soil chemical, physical, climate related and biotic (arthropod density and biomass, ground beetle density, carabid density indicators were analysed at seven different study sites in Slovakia. On average, the density of earthworms was nearly twice as high in PG compared to AL. Among five soil types used as arable land, Fluvisols created the most suitable conditions for earthworm abundance and biomass. We recorded a significant correlation between ED, EB and soil moisture in arable land. In permanent grasslands, the main climate related factor was soil temperature. Relationships between earthworms and some chemical properties (pH, available nutrients were observed only in arable land. Our findings indicate trophic interaction between earthworms and carabids in organically managed arable land. Comprehensive assessment of observed relationships can help in earthworm management to achieve sustainable agricultural systems.

  18. Differential activation of sporamin expression in response to abiotic mechanical wounding and biotic herbivore attack in the sweet potato

    Science.gov (United States)

    2014-01-01

    Background Plants respond differently to mechanical wounding and herbivore attack, using distinct pathways for defense. The versatile sweet potato sporamin possesses multiple biological functions in response to stress. However, the regulation of sporamin gene expression that is activated upon mechanical damage or herbivore attack has not been well studied. Results Biochemical analysis revealed that different patterns of Reactive oxygen species (ROS) and antioxidant mechanism exist between mechanical wounding (MW) and herbivore attack (HA) in the sweet potato leaf. Using LC-ESI-MS (Liquid chromatography electrospray ionization mass spectrometry analysis), only the endogenous JA (jasmonic acid) level was found to increase dramatically after MW in a time-dependent manner, whereas both endogenous JA and SA (salicylic acid) increase in parallel after HA. Through yeast one-hybrid screening, two transcription factors IbNAC1 (no apical meristem (NAM), Arabidopsis transcription activation factor (ATAF), and cup-shaped cotyledon (CUC)) and IbWRKY1 were isolated, which interact with the sporamin promoter fragment of SWRE (sporamin wounding-responsive element) regulatory sequences. Exogenous application of MeJA (methyl jasmonate), SA and DIECA (diethyldithiocarbamic acid, JAs biosynthesis inhibitor) on sweet potato leaves was employed, and the results revealed that IbNAC1 mediated the expression of sporamin through a JA-dependent signaling pathway upon MW, whereas both IbNAC1 and IbWRKY1 coordinately regulated sporamin expression through JA- and SA-dependent pathways upon HA. Transcriptome analysis identified MYC2/4 and JAZ2/TIFY10A (jasmonate ZIM/tify-domain), the repressor and activator of JA and SA signaling among others, as the genes that play an intermediate role in the JA and SA pathways, and these results were further validated by qRT-PCR (quantitative real-time polymerase chain reaction). Conclusion This work has improved our understanding of the differential

  19. Biotic survival in the cryobiosphere on geological scale: implication for astro/terrestrial biogeoscience

    Science.gov (United States)

    Gilichinsky, D.

    2003-04-01

    In current opinion the most fundamental aspect of any environment, the temperature regime, acts as a regulator of all of the physical-chemical reactions and forms the basis of all biological processes. Now hard data indicate the biotic survival over geological periods from subzero temperatures (down to -27oC in permafrost and to -50oC in ice) to positive one in amber and halite. All these very different environments have, nevertheless, common features: complete isolation, stability and waterproof. In such unique physical-chemical complexes, the dehydration of macromolecules and the reorganization of membrane components apparently lead to a considerable decrease or stop of metabolic activity independently of temperature. This allowed the prolonged survival of ancient microbial lineage that realize unknown possibilities of physiological and biochemical adaptation incomparably longer than any other known habitat. The ability of microorganisms to survive on geological scale within the broad limits of natural systems forces us to redefine the spatial and temporal limits of the terrestrial and extraterrestrial biospheres and suggested that universal mechanisms of such adaptation might operate for millions of years. Among new scientific directions formed on this base, the most general is the fundamental question: how long the life might be preserved and what mechanisms could ensure survival? Because the length of lifetime cannot be reproduced, this highlights the natural storages that make possible the observation of the results of biotic survival on geological scale. Of special interest is the interaction of knowledge to understanding of the limits of the deep cold biosphere as a depository of ancient active biosignatures (biogases, biominerals, pigments, lipids, enzymes, proteins, RNA/DNA fragments) and viable cells. The last are the only known a huge mass of organisms that have retained viability over geological periods and upon thawing, renew physiological activity

  20. The effects of flow rate and concentration on nitrobenzene removal in abiotic and biotic zero-valent iron columns

    DEFF Research Database (Denmark)

    Yin, Weizhao; Wu, Jinhua; Huang, Weilin

    2016-01-01

    .6% in the abiotic column and from 85.6 to 62.5% in the biotic column. The results also showed that the sequestration capacity and chemical reduction capacity were respectively 72% and 157.6% higher in the biotic column than in the abiotic column at the same tested hydraulic conditions and NB loadings. The optimal......Abstract This study investigated the effects of varying nitrobenzene (NB) loadings via increasing flow rate or influent NB concentration mode on the removal efficiency in zero-valent iron (ZVI) columns sterilized (abiotic) or preloaded with acclimated microorganisms (biotic). It was shown...... that physical sequestration via adsorption/co-precipitation and reductive transformation of NB to aniline (AN) were the two major mechanisms for the NB removal in both abiotic and biotic ZVI columns. The NB removal efficiency decreased in both columns as the flow rate increased from 0.25 to 1.0 mL min− 1...

  1. The biodiversity and biotic integration in the oak-wood of middle Russian partially wooded steppe districts

    Directory of Open Access Journals (Sweden)

    V. I. Reutskaya

    2009-01-01

    Full Text Available In this article there are givin the problems of biotic integration in the oak-wood of partially wooded steppe destrikts. There was studying the vitality dependens of oaks from their composition diversity.

  2. Impact of phenolic compounds and related enzymes in Sorghum varieties for resistance and susceptibility to biotic and abiotic stresses

    NARCIS (Netherlands)

    Dicko, M.H.; Gruppen, H.; Barro, C.; Traore, A.S.; Berkel, van W.J.H.; Voragen, A.G.J.

    2005-01-01

    Contents of phenolic compounds and related enzymes before and after sorghum grain germination were compared between varieties either resistant or susceptible to biotic (sooty stripe, sorghum midge, leaf anthracnose, striga, and grain molds) and abiotic (lodging, drought resistance, and photoperiod

  3. Biotic and a-biotic Mn and Fe cycling in deep sediments across a gradient of sulfate reduction rates along the California margin

    Science.gov (United States)

    Schneider-Mor, A.; Steefel, C.; Maher, K.

    2011-12-01

    The coupling between the biological and a-biotic processes controlling trace metals in deep marine sediments are not well understood, although the fluxes of elements and trace metals across the sediment-water interface can be a major contribution to ocean water. Four marine sediment profiles (ODP leg 167 sites 1011, 1017, 1018 and 1020)were examined to evaluate and quantify the biotic and abiotic reaction networks and fluxes that occur in deep marine sediments. We compared biogeochemical processes across a gradient of sulfate reduction (SR) rates with the objective of studying the processes that control these rates and how they affect major elements as well as trace metal redistribution. The rates of sulfate reduction, methanogenesis and anaerobic methane oxidation (AMO) were constrained using a multicomponent reactive transport model (CrunchFlow). Constraints for the model include: sediment and pore water concentrations, as well as %CaCO3, %biogenic silica, wt% carbon and δ13C of total organic carbon (TOC), particulate organic matter (POC) and mineral associated carbon (MAC). The sites are distinguished by the depth of AMO: a shallow zone is observed at sites 1018 (9 to 19 meters composite depth (mcd)) and 1017 (19 to 30 mcd), while deeper zones occur at sites 1011 (56 to 76 mcd) and 1020 (101 to 116 mcd). Sulfate reduction rates at the shallow AMO sites are on the order 1x10-16 mol/L/yr, much faster than rates in the deeper zone sulfate reduction (1-3x10-17 mol/L/yr), as expected. The dissolved metal ion concentrations varied between the sites, with Fe (0.01-7 μM) and Mn (0.01-57 μM) concentrations highest at Site 1020 and lowest at site 1017. The highest Fe and Mn concentrations occurred at various depths, and were not directly correlated with the rates of sulfate reduction and the maximum alkalinity values. The main processes that control cycling of Fe are the production of sulfide from sulfate reduction and the distribution of Fe-oxides. The Mn distribution

  4. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Phase I. Final report. Vol. 4

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

    1984-05-01

    Licensing and regulation of commercial low-level waste (CLLW) burial facilities require that anticipated risks associated with burial sites be evaluated for the life of the facility. This work reviewed the existing capability to evaluate dose to man resulting from the potential redistribution of buried radionuclides by plants and animals that we have termed biotic transport. Through biotic transport, radionuclides can be moved to locations where they can enter exposure pathways to man. We found that predictive models currently in use did not address the long-term risks resulting from the cumulative transport of radionuclides. Although reports in the literature confirm that biotic transport phenomena are common, assessments routinely ignore the associated risks or dismiss them as insignificant without quantitative evaluation. To determine the potential impacts of biotic transport, we made order-of-magnitude estimates of the dose to man for biotic transport processes at reference arid and humid CLLW disposal sites. Estimated doses to site residents after assumed loss of institutional control were comparable to dose estimates for the intruder-agricultural scenario defined in the DEIS for 10 CFR 61 (NRC). The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by order of magnitude estimates presented in this study. 17 references, 10 figures, 8 tables.

  5. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Phase I. Final report. Vol. 4

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

    1984-05-01

    Licensing and regulation of commercial low-level waste (CLLW) burial facilities require that anticipated risks associated with burial sites be evaluated for the life of the facility. This work reviewed the existing capability to evaluate dose to man resulting from the potential redistribution of buried radionuclides by plants and animals that we have termed biotic transport. Through biotic transport, radionuclides can be moved to locations where they can enter exposure pathways to man. We found that predictive models currently in use did not address the long-term risks resulting from the cumulative transport of radionuclides. Although reports in the literature confirm that biotic transport phenomena are common, assessments routinely ignore the associated risks or dismiss them as insignificant without quantitative evaluation. To determine the potential impacts of biotic transport, we made order-of-magnitude estimates of the dose to man for biotic transport processes at reference arid and humid CLLW disposal sites. Estimated doses to site residents after assumed loss of institutional control were comparable to dose estimates for the intruder-agricultural scenario defined in the DEIS for 10 CFR 61 (NRC). The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by order of magnitude estimates presented in this study. 17 references, 10 figures, 8 tables

  6. Abiotic-biotic characterization of Pt/Ir microelectrode arrays in chronic implants

    Directory of Open Access Journals (Sweden)

    Abhishek ePrasad

    2014-02-01

    Full Text Available Pt/Ir electrodes have been extensively used in neurophysiology research in recent years as they provide more inert recording surface as compared to tungsten or stainless steel. While floating microelectrode arrays consisting of Pt/Ir electrodes are an option for neuroprosthetic applications, long-term in vivo functional performance characterization of these FMAs is lacking. In this study, we have performed comprehensive abiotic-biotic characterization of Pt/Ir arrays in twelve rats with implant periods ranging from one week up to six months. Each of the FMAs consisted of 16-channel, 1.5mm long, and 75µm diameter microwires with tapered tips that were implanted into the somatosensory cortex. Abiotic characterization included (1 pre-implant and post-explant scanning electron microscopy to study recording site changes, insulation delamination and cracking, and (2 chronic in vivo electrode impedance spectroscopy. Biotic characterization included study of microglial responses using a panel of antibodies, such as Iba1, ED1, and anti-ferritin, the latter being indicative of blood-brain barrier disruption. Significant structural variation was observed pre-implantation among the arrays in the form of irregular insulation, cracks in insulation/recording surface, and insulation delamination. We observed delamination and cracking of insulation in almost all electrodes post-implantation. These changes altered the electrochemical surface area of the electrodes and resulted in declining impedance over the long-term due to formation of electrical leakage pathways. In general, the decline in impedance corresponded with poor electrode functional performance, which was quantified via electrode yield. Our abiotic results suggest that manufacturing variability and insulation material as an important factor contributing to electrode failure. Biotic results show that electrode performance was not correlated with microglial activation (neuroinflammation as we were

  7. Biotic potential and reproductive parameters of Spodoptera eridania (Stoll (Lepidoptera, Noctuidae in the laboratory

    Directory of Open Access Journals (Sweden)

    Débora Goulart Montezano

    2013-09-01

    Full Text Available Biotic potential and reprodutcive parameters of Spodoptera eridania (Stoll (Lepidoptera, Noctuidae in the laboratory: This study aimed to evaluate the biotic potential and reproductive parameters of Spodoptera eridania (Stoll, 1782 under controlled conditions (25 ± 1ºC, 70 ± 10% RH and 14 hour photophase. The longevity, pre-, post- and oviposition periods, fecundity and fertility of 15 couples was evaluated. The longevity of females (10.80 days was not significantly higher than those of males (9.27 days. The mean durations of the pre, post and oviposition periods were 2.067, 0.600 and 8.133 days, respectively. The mean fecundity per female was 1,398 eggs and the mean fertility was 1,367.50 larvae. On average, females copulated 1.133 times. A strong positive correlation was observed between the number of mating and fecundity (r = 0.881, P <0.001. However a strong negative correlation was observed between the number of copulations and the duration of the pre-oviposition period (r = -0.826, P = 0.002 and longevity (r = -0.823, P = 0.001. The biotic potential of S. eridania was estimated at 1.894 x 10(25 individuals/female/year. The net reproductive rate (Ro was 560.531 times per generation and the mean generation time (T was 35.807 days. The intrinsic rate of increase (rm was 0.177, with a finite rate of increase (l of 1.193, per week

  8. Mechanical stress induces biotic and abiotic stress responses via a novel cis-element.

    Directory of Open Access Journals (Sweden)

    Justin W Walley

    2007-10-01

    Full Text Available Plants are continuously exposed to a myriad of abiotic and biotic stresses. However, the molecular mechanisms by which these stress signals are perceived and transduced are poorly understood. To begin to identify primary stress signal transduction components, we have focused on genes that respond rapidly (within 5 min to stress signals. Because it has been hypothesized that detection of physical stress is a mechanism common to mounting a response against a broad range of environmental stresses, we have utilized mechanical wounding as the stress stimulus and performed whole genome microarray analysis of Arabidopsis thaliana leaf tissue. This led to the identification of a number of rapid wound responsive (RWR genes. Comparison of RWR genes with published abiotic and biotic stress microarray datasets demonstrates a large overlap across a wide range of environmental stresses. Interestingly, RWR genes also exhibit a striking level and pattern of circadian regulation, with induced and repressed genes displaying antiphasic rhythms. Using bioinformatic analysis, we identified a novel motif overrepresented in the promoters of RWR genes, herein designated as the Rapid Stress Response Element (RSRE. We demonstrate in transgenic plants that multimerized RSREs are sufficient to confer a rapid response to both biotic and abiotic stresses in vivo, thereby establishing the functional involvement of this motif in primary transcriptional stress responses. Collectively, our data provide evidence for a novel cis-element that is distributed across the promoters of an array of diverse stress-responsive genes, poised to respond immediately and coordinately to stress signals. This structure suggests that plants may have a transcriptional network resembling the general stress signaling pathway in yeast and that the RSRE element may provide the key to this coordinate regulation.

  9. Meta-analysis: abundance, behavior, and hydraulic energy shape biotic effects on sediment transport in streams.

    Science.gov (United States)

    Albertson, L K; Allen, D C

    2015-05-01

    An increasing number of studies have emphasized the need to bridge the disciplines of ecology and geomorphology. A large number of case studies show that organisms can affect erosion, but a comprehensive understanding of biological impacts on sediment transport conditions is still lacking. We use meta-analysis to synthesize published data to quantify the effects of the abundance, body size, and behavior of organisms on erosion in streams. We also explore the influence of current velocity, discharge, and sediment grain size on the strength of biotic effects on erosion. We found that species that both increase erosion (destabilizers) and decrease erosion (stabilizers) can alter incipient sediment motion, sediment suspension, and sediment deposition above control conditions in which the organisms were not present. When abundance was directly manipulated, these biotic effects were consistently stronger in the higher abundance treatment, increasing effect sizes by 66%. Per capita effect size and per capita biomass were also consistently positively correlated. Fish and crustaceans were the most studied organisms, but aquatic insects increased the effect size by 550 x compared to other types of organisms after accounting for biomass. In streams with lower discharge and smaller grain sizes, we consistently found stronger biotic effects. Taken collectively, these findings provide synthetic evidence that biology can affect physical processes in streams, and these effects can be mediated by hydraulic energy. We suggest that future studies focus on understudied organisms, such as biofilms, conducting experiments under realistic field conditions, and developing hypotheses for the effect of biology on erosion and velocity currents in the context of restoration to better understand the forces that mediate physical disturbances in stream ecosystems.

  10. Identification and expression analysis of WRKY family genes under biotic and abiotic stresses in Brassica rapa.

    Science.gov (United States)

    Kayum, Md Abdul; Jung, Hee-Jeong; Park, Jong-In; Ahmed, Nasar Uddin; Saha, Gopal; Yang, Tae-Jin; Nou, Ill-Sup

    2015-02-01

    WRKY proteins constitute one of the largest transcription factor families in higher plants, and they are involved in multiple biological processes such as plant development, metabolism, and responses to biotic and abiotic stresses. Genes of this family have been well documented in response to many abiotic and biotic stresses in many plant species, but not yet against Pectobacterium carotovorum subsp. carotovorum and Fusarium oxysporum f.sp. conglutinans in any of the plants. Moreover, potentiality of a specific gene may vary depending on stress conditions and genotypes. To identify stress resistance-related potential WRKY genes of Brassica rapa, we analyzed their expressions against above-mentioned pathogens and cold, salt, and drought stresses in B. rapa. Stress resistance-related functions of all Brassica rapa WRKY (BrWRKY) genes were firstly analyzed through homology study with existing biotic and abiotic stress resistance-related WRKY genes of other plant species and found a high degree of homology. We then identified all BrWRKY genes in a Br135K microarray dataset, which was created by applying low-temperature stresses to two contrasting Chinese cabbage doubled haploid (DH) lines, Chiifu and Kenshin, and selected 41 BrWRKY genes with high and differential transcript abundance levels. These selected genes were further investigated under cold, salt, and drought stresses as well as after infection with P. carotovorum subsp. carotovorum and F. oxysporum f.sp. conglutinans in B. rapa. The selected genes showed an organ-specific expression, and 22 BrWRKY genes were differentially expressed in Chiifu compared to Kenshin under cold and drought stresses. Six BrWRKY genes were more responsive in Kenshin compared to Chiffu under salt stress. In addition, eight BrWRKY genes showed differential expression after P. carotovorum subsp. carotovorum infection and five genes after F. oxysporum f.sp. conglutinans infection in B. rapa. Thus, the differentially expressed Br

  11. Carbon trading and carbon taxation: how to consider biotic sources and sinks

    International Nuclear Information System (INIS)

    Madlener, Reinhard; Schlamadinger, Bernhard

    1999-01-01

    The Kyoto Protocol (KP) to the UNFCCC includes land-use change and forestry in the carbon accounting process, limited to afforestation, reforestation and deforestation since 1990, and explicitly provides for the option of using a variety of flexibility mechanisms to meet the greenhouse gas (GHG) reduction targets stipulated in a more cost-efficient manner. Domestically, different countries might adopt different approaches to achieve their emission reduction objectives, such as carbon trading or carbon taxation, and it is not clear to date what the implications for bioenergy use, forestry, and land-use change can be expected to be. With respect to national GHG emissions trading, the main issues studied in this paper are: Should trading of fossil fuel emissions allowances be coupled with trading of biotic credits and debits? Should credits for carbon sequestration in forests be auctioned or grandfathered? Should there be a distinction between a carbon permit issued for an additional biotic sink and those issued for fossil fuel carbon emissions? Is there a difference for biotic carbon sinks and sources between one-time permits and permits that allow a continued release of GHG over some pre-specified time? Should permits be issued only for the carbon-stock changes that count under the KP? With respect to national carbon taxation schemes, two questions are investigated: Should a tax credit be given for afforestation/reforestation (and a tax debit for deforestation)? Should tax credits also be given for projects that sequester carbon but do not count under the KP (such as forest protection rather than forest management)? For both schemes a crucial point is that by the formulation chosen in the KP two different classes of forest are created (i.e. those counted and those not counted under the KP), so that the implications for land prices might be significant. From a conceptual point of view this paper addresses the above-mentioned questions and contrasts some of the major

  12. Spatially dependent biotic and abiotic factors drive survivorship and physical structure of green roof vegetation.

    Science.gov (United States)

    Aloisio, Jason M; Palmer, Matthew I; Giampieri, Mario A; Tuininga, Amy R; Lewis, James D

    2017-01-01

    Plant survivorship depends on biotic and abiotic factors that vary at local and regional scales. This survivorship, in turn, has cascading effects on community composition and the physical structure of vegetation. Survivorship of native plant species is variable among populations planted in environmentally stressful habitats like urban roofs, but the degree to which factors at different spatial scales affect survivorship in urban systems is not well understood. We evaluated the effects of biotic and abiotic factors on survivorship, composition, and physical structure of two native perennial species assemblages, one characterized by a mixture of C 4 grasses and forbs (Hempstead Plains, HP) and one characterized by a mixture of C 3 grasses and forbs (Rocky Summit, RS), that were initially sown at equal ratios of growth forms (5:1:4; grass, N-fixing forb and non-N-fixing forb) in replicate 2-m 2 plots planted on 10 roofs in New York City (New York, USA). Of 24 000 installed plants, 40% survived 23 months after planting. Within-roof factors explained 71% of variation in survivorship, with biotic (species identity and assemblage) factors accounting for 54% of the overall variation, and abiotic (growing medium depth and plot location) factors explaining 17% of the variation. Among-roof factors explained 29% of variation in survivorship and increased solar radiation correlated with decreased survivorship. While growing medium properties (pH, nutrients, metals) differed among roofs there was no correlation with survivorship. Percent cover and sward height increased with increasing survivorship. At low survivorship, cover of the HP assemblage was greater compared to the RS assemblage. Sward height of the HP assemblage was about two times greater compared to the RS assemblage. These results highlight the effects of local biotic and regional abiotic drivers on community composition and physical structure of green roof vegetation. As a result, initial green roof plant

  13. Abiotic and biotic factors influencing the winter distribution of predatory insects.

    Science.gov (United States)

    Thomas, Matthew B; Mitchell, Heidi J; Wratten, Stephen D

    1992-01-01

    Various environmental factors were investigated to analyse those involved in successful overwintering and possibly overwintering site selection for Tachyporus hypnorum and Demetrias atricapillus, both important coleopteran predators of cereal aphids. The results of the study indicated food supply to be important for both predator species during the winter period, although the role of biotic factors in site selection in the autumn could not be clearly demonstrated. The winter distribution of the two species could, however, be explained well in terms of abiotic factors. It is suggested that these and other similar predator species have well-defined overwintering requirements and that these can be exploited in the management of field boundary habitats.

  14. Identification of genetic components involved in Lotus-endophyte interactions

    DEFF Research Database (Denmark)

    Zgadzaj, Rafal Lukasz

    colonisation of below-ground plant organs. It focused on bacterial endophyte, Rhizobium KAW12, colonisation of spontaneously formed nodules in snf1 mutants and symbiotic signalling mutants in a snf1 background. Additionally, participation of genes required for rhizobial accomodation during endophytic invasion...... was tested by coinoculation experiments with Rhizobium KAW12 and nodule inducing strains or their symbiotically deficient mutants. Such approaches allowed to identify genes possibly involved in host-endophyte recognition. Additionally, bacterial mutants used in these screenings pointed towards...... testing single host-single microsymbiont interactions, an effort was made to study relationships in between plants and the soil microbiome. Comparison of results for the nfr5 mutant of Lotus with results previously obtained for Arabidopsis suggested that plants were able to build specific bacterial...

  15. Using fish communities to assess streams in Romania: Initial development of an index of biotic integrity

    Science.gov (United States)

    Angermeier, P.L.; Davideanu, G.

    2004-01-01

    Multimetric biotic indices increasingly are used to complement physicochemical data in assessments of stream quality. We initiated development of multimetric indices, based on fish communities, to assess biotic integrity of streams in two physiographic regions of central Romania. Unlike previous efforts to develop such indices for European streams, our metrics and scoring criteria were selected largely on the basis of empirical relations in the regions of interest. We categorised 54 fish species with respect to ten natural-history attributes, then used this information to compute 32 candidate metrics of five types (taxonomic, tolerance, abundance, reproductive, and feeding) for each of 35 sites. We assessed the utility of candidate metrics for detecting anthropogenic impact based on three criteria: (a) range of values taken, (b) relation to a site-quality index (SQI), which incorporated information on hydrologic alteration, channel alteration, land-use intensity, and water chemistry, and (c) metric redundancy. We chose seven metrics from each region to include in preliminary multimetric indices (PMIs). Both PMIs included taxonomic, tolerance, and feeding metrics, but only two metrics were common to both PMIs. Although we could not validate our PMIs, their strong association with the SQI in each region suggests that such indices would be valuable tools for assessing stream quality and could provide more comprehensive assessments than the traditional approaches based solely on water chemistry.

  16. Alcohol dehydrogenase 1 (ADH1) confers both abiotic and biotic stress resistance in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Liu, Wen; Yao, Yue; Wei, Yunxie; Chan, Zhulong

    2017-09-01

    Although the transcriptional regulation and upstream transcription factors of AtADH1 in response to abiotic stress are widely revealed, the in vivo roles of AtADH1 remain unknown. In this study, we found that the expression of AtADH1 was largely induced after salt, drought, cold and pathogen infection. Further studies found that AtADH1 overexpressing plants were more sensitive to abscisic acid (ABA) in comparison to wide type (WT), while AtADH1 knockout mutants showed no significant difference compared with WT in ABA sensitivity. Consistently, AtADH1 overexpressing plants showed improved stress resistance to salt, drought, cold and pathogen infection than WT, but the AtADH1 knockout mutants had no significant difference in abiotic and biotic stress resistance. Moreover, overexpression of AtADH1 expression increased the transcript levels of multiple stress-related genes, accumulation of soluble sugars and callose depositions. All these results indicate that AtADH1 confers enhanced resistance to both abiotic and biotic stresses. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Variability in connectivity patterns of fish with ontogenetic migrations: Modelling effects of abiotic and biotic factors

    Directory of Open Access Journals (Sweden)

    Susanne Eva Tanner

    2015-10-01

    Full Text Available Connectivity is a critical property of marine fish populations as it drives population replenishment, determines colonization patterns and the resilience of populations to harvest. Understanding connectivity patterns is particularly important in species that present ontogenetic migrations and segregated habitat use during their life history, such as marine species with estuarine nursery areas. Albeit challenging, fish movement can be estimated and quantified using different methodologies depending on the life history stages of interest (e.g. biophysical modelling, otolith chemistry, genetic markers. Relative contributions from estuarine nursery areas to the adult coastal populations were determined using otolith elemental composition and maximum likelihood estimation for four commercially important species (Dicentrarchus labrax, Plathichtys flesus, Solea senegalensis and Solea solea and showed high interannual variability. Here, the effects of abiotic and biotic factors on the observed variability in connectivity rates and extent between estuarine juvenile and coastal adult subpopulations are investigated using generalized linear models (GLM and generalized mixed models (GMM. Abiotic factors impacting both larval and juvenile life history stages are included in the models (e.g. wind force and direction, NAO, water temperature while biotic factors relative to the estuarine residency of juvenile fish are evaluated (e.g. juvenile density, food availability. Factors contributing most to the observed variability in connectivity rates are singled out and compared among species. General trends are identified and results area discussed in the general context of identifying potential management frameworks applicable to different life stages and which may prove useful for ontogenetically migrating species.

  18. Integrated Record of Terrestrial Biotic Change from the Upper Triassic Chinle Formation of northern New Mexico

    Science.gov (United States)

    Irmis, R. B.; Lindström, S.; Dunlavey, M.; Whiteside, J. H.

    2010-12-01

    The Triassic Period was an interval of major biotic and environmental changes sandwiched between two major mass extinctions. During the Late Triassic (235-201.3 Ma), dinosaurs originated and diversified across Pangaea, and several major extant vertebrate groups also appeared for the first time. Unfortunately, few detailed stratigraphically-precise local-regional paleontological records exist for continental Triassic strata, which hinders any attempt to understand the tempo and mode of biotic change through the Late Triassic. We present a new stratigraphically well-constrained fossil vertebrate and palynomorph record (10-15 Ma in duration) from the upper Chinle Formation of the Chama Basin, northern New Mexico, an area that is famous for preserving one of the best records of early dinosaurs in North America. Our data indicate that vertebrate faunas were generally stable, experiencing only one identifiable species turnover event. Dinosaurs, although relatively diverse, were never abundant components of the fauna. Contemporaneous palynological records indicate that floral composition fluctuated considerably. The drought-tolerant conifer pollen Enzonalasporites and other gymnosperms such as Alisporites and Protodiploxypinus dominate most palynofloral assemblages, but there is a distinct increase in fern spore abundance near the top of the section. In combination with evidence of variability from organic carbon stable isotopes, these data indicate that the vertebrate fauna, including early dinosaurs, remained stable over millions of years despite living within a dynamic ecosystem associated with rapidly changing environmental conditions.

  19. Biotic potential and reproductive parameters of Spodoptera dolichos (Lepidoptera: Noctuidae in the laboratory

    Directory of Open Access Journals (Sweden)

    Débora G. Montezano

    2015-12-01

    Full Text Available ABSTRACT The biotic potential and reproductive parameters of Spodoptera dolichos (Fabricius, 1794 were evaluated under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase. The longevity, pre-, post- and oviposition periods, fecundity, and fertility of 25 couples were evaluated. The longevity of females (12.9 days was not significantly different than that of males (12.4 days. The mean durations of the pre-, post- and oviposition periods were 3.0, 0.4 and 10.4 days, respectively. The mean fecundity was 4,086.0 eggs per female and mean fertility was 3,557.8 larvae per female. On average, a female copulated 1.4 times. The biotic potential of S. dolichos was estimated at 7.138 x 1018 individuals/female/year. The net reproductive rate (Ro was 1,711.98 times per generation and the mean generation time (T was 56.19 days. The intrinsic rate of increase (rm was 0.133, with a finite rate of increase (l of 1.142 per day. These results are compared with other species from Spodoptera and their relevance for management strategies of S. dolichos.

  20. Identification of putative MAPK kinases in Oryza minuta and O. sativa responsive to biotic stresses.

    Science.gov (United States)

    You, Min Kyoung; Oh, Seung-Ick; Ok, Sung Han; Cho, Sung Ki; Shin, Hyun Young; Jeung, Ji Ung; Shin, Jeong Sheop

    2007-02-28

    The mitogen-activated protein kinase (MAPK) signaling cascade is critical for regulating plant defense systems against various kinds of pathogen and environmental stresses. One component of this cascade, the MAP kinase kinases (MAPKK), has not yet been shown to be induced in plants following biotic attacks, such as those by insects and fungi. We describe here a gene coding for a blast (Magnaporthe grisea)- and insect (Nilaparvata lugens)-responsive putative MAPK kinase, OmMKK1 (Oryza minuta MAPKK 1), which was identified in a library of O. minuta expressed sequence tags (ESTs). Two copies of OmMKK1 are present in the O. minuta genome. They encode a predicted protein with molecular mass 39 kDa and pI of 6.2. Transcript patterns following imbibition of plant hormones such as methyl jasmonic acid (MeJA), ethephone, salicylic acid (SA) and abscisic acid (ABA), as well as exposure to methyl viologen (MV), revealed that the expression of OmMKK1 is related to defense response signaling pathways. A comparative analysis of OmMKK1 and its O. sativa ortholog OsMKK1 showed that both were induced by stress-related hormones and biotic stresses, but that the kinetics of their responses differed despite their high amino acid sequence identity (96%).

  1. Fragrance Allergens, Overview with a Focus on Recent Developments and Understanding of Abiotic and Biotic Activation

    Directory of Open Access Journals (Sweden)

    Johanna Bråred Christensson

    2016-06-01

    Full Text Available Fragrances and fragranced formulated products are ubiquitous in society. Contact allergies to fragrance chemicals are among the most common findings when patch-testing patients with suspected allergic contact dermatitis, as well as in studies of contact allergy in the general population. The routine test materials for diagnosing fragrance allergy consist mainly of established mixes of fragrance compounds and natural extracts. The situation is more complex as several fragrance compounds have been shown to be transformed by activation inside or outside the skin via abiotic and/or biotic activation, thus increasing the risk of sensitization. For these fragrance chemicals, the parent compound is often non-allergenic or a very weak allergen, but potent sensitizers will be formed which can cause contact allergy. This review shows a series of fragrance chemicals with well-documented abiotic and/or biotic activation that are indicative and illustrative examples of the general problem. Other important aspects include new technologies such as ethosomes which may enhance both sensitization and elicitation, the effect on sensitization by the mixtures of fragrances found in commercial products and the effect of antioxidants. A contact allergy to fragrances may severely affect quality of life and many patients have multiple allergies which further impact their situation. Further experimental and clinical research is needed to increase the safety for the consumer.

  2. Biotic indices for assessing the status of coastal waters: a review of strengths and weaknesses.

    Science.gov (United States)

    Martínez-Crego, Begoña; Alcoverro, Teresa; Romero, Javier

    2010-05-01

    Biotic indices have become key assessment tools in most recent national and trans-national policies aimed at improving the quality of coastal waters and the integrity of their associated ecosystems. In this study we analyzed 90 published biotic indices, classified them into four types, and analyzed the strengths and weaknesses of each type in relation to the requirements of these policies. We identified three main type-specific weaknesses. First, the problems of applicability, due to practical and conceptual difficulties, which affect most indices related to ecosystem function. Second, the failure of many indices based on structural attributes of the community (e.g. taxonomic composition) to link deterioration with causative stressors, or to provide an early-detection capacity. Third, the poor relevance to the ecological integrity of indices based on attributes at the sub-individual level (e.g. multi-biomarkers). Additionally, most indices still fail on two further aspects: the broad-scale applicability and the definition of reference conditions. Nowadays, the most promising approach seems to be the aggregation of indices with complementary strengths, and obtained from different biological communities.

  3. INDEKS BIOTIK TINGKAT FAMILY: UPAYA AWAL PENYUSUNAN INDEKS BIOTIK UNTUK SUNGAI TROPIS INDONESIA (Famely Biotic Index : Prelimenary Establishment of Biotic Index for Indoensian Tropical Stream

    Directory of Open Access Journals (Sweden)

    Sri Puji Saraswati

    2009-11-01

    Full Text Available ABSTRAK Suatu indeks biotik dicoba dikembangkan untuk sungai tropik di Indonesia, dengan menggunakan uji penelitian di sungai Gajahwong di Yogyakarta. Variabel lingkungan yang diperoleh pada musim kemarau dan musim hujan diklasifikasikan berdasarkan lokasi sampel menurut "penurunan gradien" di sumbu I dan sumbu 2 dariAnalisis Komponen Utama (Principle Component Analysis. Tiga metode analisis digunakan untuk menghasilkan indeks biotik makroinvertebrata/ makrobenthos yang ada di sungai yang dipengaruhi oleh limbah rumah tangga dan industri. Hasil penelitian menunjukkan bahwa indeks biotik yang disusun dapat digunakan sebagai indikator yang baik untuk merefleksikan kondisi habitat di sungai yang diteliti dan memberikan nilai korelasi yang baik dengan indeks lain yang menggunakan identifikasi tingkat famili.   ABSTRACT A biotic index was tried to be developed for Indonesian tropical stream, taking as a test case Gajahwong Stream in Yogyakarta. Environmental variables investigated in dry season and rainy season are classified based on the sampling sites according to decreasing gradient in axis 1 and axis 2 of Principal Component Analysis. Three metrics were used to derive the tolerance value of macroinvertebrates assemblages in stream affected by municipal and industrial waste.  The result showed that the tolerance values derived is a good indicator in reflecting the habitat condition in the study stream and have good relationship to the other index of family level identification.

  4. TOPOGRAPHIC PATTERNS OF ABOVE- AND BELOW-GROUND PRODUCTION AND NITROGEN CYCLING IN ALPINE TUNDRA. (R823442)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Phenology of perennial native grass below-ground axillary buds in the northern mixed-grass prairie

    Science.gov (United States)

    Vegetative reproduction from belowground bud banks is the primary driver of grassland systems. Despite the importance of vegetative reproduction, the timing of belowground bud recruitment is unknown for most dominant, perennial native grasses as is the relationship between bud development and envir...

  6. Above-ground and below-ground competition between the willow Salix caprea L. and its understorey

    Czech Academy of Sciences Publication Activity Database

    Mudrák, Ondřej; Hermová, M.; Tesnerová, C.; Rydlová, Jana; Frouz, Jan

    2016-01-01

    Roč. 27, č. 1 (2016), s. 156-164 ISSN 1100-9233 R&D Projects: GA ČR GA13-10377S; GA ČR(CZ) GA15-11635S Institutional support: RVO:67985939 ; RVO:60077344 Keywords : Mycorrhizae * Roots * Succession * Understorey * Willow Subject RIV: EH - Ecology, Behaviour Impact factor: 2.924, year: 2016

  7. Modeling below-ground biomass to improve sustainable management of Actaea racemosa, a globally important medicinal forest product

    Science.gov (United States)

    James L. Chamberlain; Gabrielle Ness; Christine J. Small; Simon J. Bonner; Elizabeth B. Hiebert

    2013-01-01

    Non-timber forest products, particularly herbaceous understory plants, support a multi-billion dollar industry and are extracted from forests worldwide for their therapeutic value. Tens of thousands of kilograms of rhizomes and roots of Actaea racemosa L., a native Appalachian forest perennial, are harvested every year and used for the treatment of...

  8. Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux

    Science.gov (United States)

    Christian P. Giardina; Creighton M. Litton; Susan E. Crow; Gregory P Asner

    2014-01-01

    The universally observed exponential increase in soil-surface CO2 effux (‘soil respiration’; FS) with increasing temperature has led to speculation that global warming will accelerate soil organic carbon (SOC) decomposition, reduce SOC storage, and drive a positive feedback to future warming. However, interpreting temperature–FS relationships,...

  9. Thirty-three year changes in above- and below-ground biomass in northern hardwood stands in Vermont

    Science.gov (United States)

    A. H. Johnson; G. R. Strimbeck

    1996-01-01

    In 1957-1960, R. O. Curtis and B. W. Post surveyed 81 even aged (45-90 y old) northern hardwood stands on acid till soils over the length of Vermont's Green Mountains. The purpose of the original study was to determine predictive relationships between site index and site characteristics, including latitude, elevation, soil drainage class, soil organic matter...

  10. The below-ground perspective of forest plants: soil provides mainly organic nitrogen for plants and mycorrhizal fungi.

    Science.gov (United States)

    Inselsbacher, Erich; Näsholm, Torgny

    2012-07-01

    • Nitrogen (N) availability has a major impact on a wide range of biogeochemical processes in terrestrial ecosystems. Changes in N availability modify the capacity of plants to sequester carbon (C), but despite the crucial importance for our understanding of terrestrial ecosystems, the relative contribution of different N forms to plant N nutrition in the field is not known. Until now, reliably assessing the highly dynamic pool of plant-available N in soil microsites was virtually impossible, because of the lack of adequate sampling techniques. • For the first time we have applied a novel microdialysis technique for disturbance-free monitoring of diffusive fluxes of inorganic and organic N in 15 contrasting boreal forest soils in situ. • We found that amino acids accounted for 80% of the soil N supply, while ammonium and nitrate contributed only 10% each. In contrast to common soil extractions, microdialysis revealed that the majority of amino acids are available for plant and mycorrhizal uptake. • Our results suggest that the N supply of boreal forest soils is dominated by organic N as a major component of plant-available N and thus as a regulator of growth and C sequestration. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  11. Tritium Packages and 17th RH Canister Categories of Transuranic Waste Stored Below Ground within Area G

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Kenneth Marshall [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-01

    A large wildfire called the Las Conchas Fire burned large areas near Los Alamos National Laboratory (LANL) in 2011 and heightened public concern and news media attention over transuranic (TRU) waste stored at LANL’s Technical Area 54 (TA-54) Area G waste management facility. The removal of TRU waste from Area G had been placed at a lower priority in budget decisions for environmental cleanup at LANL because TRU waste removal is not included in the March 2005 Compliance Order on Consent (Reference 1) that is the primary regulatory driver for environmental cleanup at LANL. The Consent Order is a settlement agreement between LANL and the New Mexico Environment Department (NMED) that contains specific requirements and schedules for cleaning up historical contamination at the LANL site. After the Las Conchas Fire, discussions were held by the U.S. Department of Energy (DOE) with the NMED on accelerating TRU waste removal from LANL and disposing it at the Waste Isolation Pilot Plant (WIPP). This report summarizes available information on the origin, configuration, and composition of the waste containers within the Tritium Packages and 17th RH Canister categories; their physical and radiological characteristics; the results of the radioassays; and potential issues in retrieval and processing of the waste containers.

  12. Quantifying carbon sequestration in forest plantations by modeling the dynamics of above and below ground carbon pools

    Science.gov (United States)

    Chris A. Maier; Kurt H. Johnsen

    2010-01-01

    Intensive pine plantation management may provide opportunities to increase carbon sequestration in the Southeastern United States. Developing management options that increase fiber production and soil carbon sequestration require an understanding of the biological and edaphic processes that control soil carbon turnover. Belowground carbon resides primarily in three...

  13. Discovery of core biotic stress responsive genes in Arabidopsis by weighted gene co-expression network analysis.

    Science.gov (United States)

    Amrine, Katherine C H; Blanco-Ulate, Barbara; Cantu, Dario

    2015-01-01

    Intricate signal networks and transcriptional regulators translate the recognition of pathogens into defense responses. In this study, we carried out a gene co-expression analysis of all currently publicly available microarray data, which were generated in experiments that studied the interaction of the model plant Arabidopsis thaliana with microbial pathogens. This work was conducted to identify (i) modules of functionally related co-expressed genes that are differentially expressed in response to multiple biotic stresses, and (ii) hub genes that may function as core regulators of disease responses. Using Weighted Gene Co-expression Network Analysis (WGCNA) we constructed an undirected network leveraging a rich curated expression dataset comprising 272 microarrays that involved microbial infections of Arabidopsis plants with a wide array of fungal and bacterial pathogens with biotrophic, hemibiotrophic, and necrotrophic lifestyles. WGCNA produced a network with scale-free and small-world properties composed of 205 distinct clusters of co-expressed genes. Modules of functionally related co-expressed genes that are differentially regulated in response to multiple pathogens were identified by integrating differential gene expression testing with functional enrichment analyses of gene ontology terms, known disease associated genes, transcriptional regulators, and cis-regulatory elements. The significance of functional enrichments was validated by comparisons with randomly generated networks. Network topology was then analyzed to identify intra- and inter-modular gene hubs. Based on high connectivity, and centrality in meta-modules that are clearly enriched in defense responses, we propose a list of 66 target genes for reverse genetic experiments to further dissect the Arabidopsis immune system. Our results show that statistical-based data trimming prior to network analysis allows the integration of expression datasets generated by different groups, under different

  14. Genetic architecture of contemporary adaptation to biotic invasions: quantitative trait locus mapping of beak reduction in soapberry bugs.

    Science.gov (United States)

    Yu, Y; Andrés, Jose A

    2014-02-19

    Biological invasions can result in new selection pressures driven by the establishment of new biotic interactions. The response of exotic and native species to selection depends critically on the genetic architecture of ecologically relevant traits. In the Florida peninsula, the soapberry bug (Jadera haematoloma) has colonized the recently introduced Chinese flametree, Koelreuteria elegans, as a host plant. Driven by feeding efficiency, the populations associated with this new host have differentiated into a new bug ecomorph characterized by short beaks more appropriate for feeding on the flattened pods of the Chinese flametree. In this study, we have generated a three-generation pedigree from crossing the long-beaked and short-beaked ecomorphs to construct a de novo linkage map and to locate putative quantitative trait locus (QTL) controlling beak length and body size in J. haematoloma. Using amplified fragment-length polymorphism markers and a two-way pseudo-testcross design, we have produced two parental maps in six linkage groups, covering the known number of chromosomes. QTL analysis revealed one significant QTL for beak length on a maternal linkage group and the corresponding paternal linkage group. Three QTL were found for body size. Through single marker regression analysis, nine single markers that could not be placed on the map were also found to be significantly associated with one or both of the two traits. Interestingly, the most significant body size QTL co-localized with the beak length QTL, suggesting linkage disequilibrium or pleiotropic effects of related traits. Our results suggest an oligogenic control of beak length.

  15. Relevance of biotic pathways to the long-term regulation of nuclear-waste disposal. Topical report on reference western arid low-level sites

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

    1982-10-01

    The purpose of the work reported here was to develop an order of magnitude estimate for the potential dose to man resulting from biotic transport mechanisms at a reference western arid low-level waste site. A description of the reference site is presented that includes the waste inventories, site characteristics and biological communities. Parameter values for biotic transport processes are based on data reported in current literature. Transport and exposure scenarios are developed for assessing biotic transport during 100 years following site closure. Calculations of radionuclide decay and waste container decomposition are made to estimate the quantities available for biotic transport. Dose to a man occupying the reference site following the 100 years of biotic transport are calculated. These dose estimates are compared to dose estimates for the intruder-agricultural scenario reported in the DEIS for 10 CFR 61 (NRC). Dose to man estimates as a result of biotic transport are estimated to be of the same order of magnitude as the dose resulting from the more commonly evaluated human intrusion scenario. The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by the findings presented in this report. These results indicate that biotic transport has the potential to influence low-level waste site performance. Through biotic transport, radionuclides may be moved to locations where they can enter exposure pathways to man

  16. ALien Biotic IndEX (ALEX) - a new index for assessing impacts of alien species on benthic communities.

    Science.gov (United States)

    Çinar, Melih Ertan; Bakir, Kerem

    2014-10-15

    Biotic indices are mainly aimed at assessing levels of deterioration caused by chemical or organic pollution. However, no biotic index to date has been developed to detect impacts of alien species on benthic communities. In this paper, a new biotic index, namely ALEX, is proposed to address the objectives of the Water Framework Directive and was tested in Mersin Bay (Levantine Sea, Turkey). Species were divided into four biogeographic groups, namely native species, casual species, established species and invasive species, and the metric considers the relative importance of these groups in samples. The index classified the ecological status of some stations which are shallow, and close to harbor and river mouths as bad or poor in February and October. The ALEX values were positively and significantly correlated with total nitrogen, silicate and silt percentage in sediment, and negatively correlated with depth and the distance from the harbor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. A comparison of different biotic indices based on benthic macro-invertebrates in italian lakes

    Directory of Open Access Journals (Sweden)

    Laura MARZIALI

    2011-02-01

    Full Text Available Benthic macroinvertebrates samples were taken from Italian lakes with different geological, morphological and chemical characteristics. Thirty-two lowland small and large lakes sampled using a grab in soft substrate were selected to develop biotic indices. Diversity indices based on species numbers - abundances and indices using species sensitivity values were compared. The lakes selected were all situated in the Alpine Ecoregion below 800 m a.s.l. and had similar chemical composition but different levels of anthropogenic pressure. Lakes with data available in different years were included as separate lakes in the analysis; littoralsublittoral samples of large lakes were also separated from profundal samples yielding a total of 41 sites for analysis. Seven different biotic indices were compared: (1 Shannon diversity index (H, (2 weighted Shannon diversity index (Hw including in the calculation a sensitivity value assigned to each species, (3 a benthic quality index based on means of three different environmental variables, measuring trophic status, weighted by species abundances (BQITS, (4 an index based on weighted means using a larger set of environmental variables (BQIENV, (5 a modified BQITS, which included both species numbers and total abundance of individuals (BQIES, (6 an index calculated according to a rarefaction method (ES, (7 an index considering indicator species based on experts judgment (BQIEJ. The indices were compared with a trophic status index (TSI constructed by joining three environmental variables: O2% saturation in the hypolimnion during summer stratification, total phosphorous and transparency during full circulation. Comparisons were also made with another environmental stress index (ENI constructed on a larger number of variables. All the biotic indices had significant correlations with both TSI and ENI. BQIES, WFD compliant and well correlated with TSI and ENI, was selected to tentatively assign the investigated lakes

  18. Forest calcium depletion and biotic retention along a soil nitrogen gradient

    Science.gov (United States)

    Perakis, Steven S.; Sinkhorn, Emily R.; Catricala, Christina; Bullen, Thomas D.; Fitzpatrick, John A.; Hynicka, Justin D.; Cromack, Kermit

    2013-01-01

    High nitrogen (N) accumulation in terrestrial ecosystems can shift patterns of nutrient limitation and deficiency beyond N toward other nutrients, most notably phosphorus (P) and base cations (calcium [Ca], magnesium [Mg], and potassium [K]). We examined how naturally high N accumulation from a legacy of symbiotic N fixation shaped P and base cation cycling across a gradient of nine temperate conifer forests in the Oregon Coast Range. We were particularly interested in whether long-term legacies of symbiotic N fixation promoted coupled N and organic P accumulation in soils, and whether biotic demands by non-fixing vegetation could conserve ecosystem base cations as N accumulated. Total soil N (0–100 cm) pools increased nearly threefold across the N gradient, leading to increased nitrate leaching, declines in soil pH from 5.8 to 4.2, 10-fold declines in soil exchangeable Ca, Mg, and K, and increased mobilization of aluminum. These results suggest that long-term N enrichment had acidified soils and depleted much of the readily weatherable base cation pool. Soil organic P increased with both soil N and C across the gradient, but soil inorganic P, biomass P, and P leaching loss did not vary with N, implying that historic symbiotic N fixation promoted soil organic P accumulation and P sufficiency for non-fixers. Even though soil pools of Ca, Mg, and K all declined as soil N increased, only Ca declined in biomass pools, suggesting the emergence of Ca deficiency at high N. Biotic conservation and tight recycling of Ca increased in response to whole-ecosystem Ca depletion, as indicated by preferential accumulation of Ca in biomass and surface soil. Our findings support a hierarchical model of coupled N–Ca cycling under long-term soil N enrichment, whereby ecosystem-level N saturation and nitrate leaching deplete readily available soil Ca, stimulating biotic Ca conservation as overall supply diminishes. We conclude that a legacy of biological N fixation can increase N

  19. A Big Bang or small bangs? Effects of biotic environment on hatching

    Directory of Open Access Journals (Sweden)

    Marina MANCA

    2008-08-01

    Full Text Available The beginning and end of diapause are two important transition points in cladoceran life history. The influence of environmental variables on the dynamics of these processes still deserves attention, especially as concerns the role of biotic factors. In this paper we focus on emergence from diapause, testing (1 whether ephippia of Daphnia obtusa Kurz can assess the presence in the water of typical planktivorous fish or ostracods, and (2 whether such an assessment results in changes in hatching strategy. Total number of hatchlings from D. obtusa ephippial eggs did not differ between the control and the treatments in which the presence of fish or ostracods could be detected (ANOVA, P = 0.884. However, hatching dynamics were different: most of the eggs hatched synchronously at day 4 (83.3% of the total hatchlings number in the control, while only a low proportion of eggs hatched on day 4 in the fish (38.3%, and ostracod treatments (24.0% of the total. Mean hatching time was longer, and variability larger, in the treatments than in the control; differences resulted statistically significant (ANOVA, P = 0.005. With respect to the control, representing a simple microcosm controlled by abiotic variables only, the treatments may be regarded as relatively complex environments, in which Daphnia is also exposed to biotic cues. Under these more complex conditions, the same number of hatchlings is obtained through different hatching dynamics. In the treatments, the first hatchlings appeared later and the hatching rate was more variable than in the control. These observations confirm previously observed patterns from laboratory experiments which tested the effect of competition and fluctuating environmental conditions (light:dark, temperature regimes on D. obtusa reproductive and demographic parameters. They are also in agreement with recently obtained evidence concerning the importance of biotic cues for hatching of ephippial eggs. Overall, the evidence

  20. The Red Queen and the Court Jester: species diversity and the role of biotic and abiotic factors through time.

    Science.gov (United States)

    Benton, Michael J

    2009-02-06

    Evolution may be dominated by biotic factors, as in the Red Queen model, or abiotic factors, as in the Court Jester model, or a mixture of both. The two models appear to operate predominantly over different geographic and temporal scales: Competition, predation, and other biotic factors shape ecosystems locally and over short time spans, but extrinsic factors such as climate and oceanographic and tectonic events shape larger-scale patterns regionally and globally, and through thousands and millions of years. Paleobiological studies suggest that species diversity is driven largely by abiotic factors such as climate, landscape, or food supply, and comparative phylogenetic approaches offer new insights into clade dynamics.

  1. Carnivorans at the Great American Biotic Interchange: new discoveries from the northern neotropics.

    Science.gov (United States)

    Forasiepi, Analia M; Soibelzon, Leopoldo H; Gomez, Catalina Suarez; Sánchez, Rodolfo; Quiroz, Luis I; Jaramillo, Carlos; Sánchez-Villagra, Marcelo R

    2014-11-01

    We report two fossil procyonids, Cyonasua sp. and Chapalmalania sp., from the late Pliocene of Venezuela (Vergel Member, San Gregorio Formation) and Colombia (Ware Formation), respectively. The occurrence of these pre-Holocene procyonids outside Argentina and in the north of South America provides further information about the Great American Biotic Interchange (GABI). The new specimens are recognized in the same monophyletic group as procyonids found in the southern part of the continent, the "Cyonasua group," formed by species of Cyonasua and Chapalmalania. The phylogenetic analysis that includes the two new findings support the view that procyonids dispersed from North America in two separate events (initially, previous to the first major migration wave-GABI 1-and then within the last major migration wave-GABI 4-). This involved reciprocal lineage migrations from North to South America, and included the evolution of South American endemic forms.

  2. Biotic control of an abiotic resource: Palmyra Atoll, a case study

    Science.gov (United States)

    Engels, M.; Heinse, R.

    2013-12-01

    The availability of abiotic resources as a control on the spatial distribution of plants in an ecosystem is well studied. Less well known is the impact of plants on the availability of abiotic resources and how this biotic control of the environment influences vegetative distribution over time. In order to investigate this question, we examined the influence of vegetation on the water balance of a tropical atoll. Palmyra is a small (2.5 km2) wet atoll in the northern Line Islands that hosts five species of native and introduced trees/shrubs, Cocos nucifera, Pisonia grandis, Tournefortia argentia, Terminalia catappa, and Scaevola sericea, accounting for ~85% percent of the vegetative coverage on the island. Using historical aerial photographs, climate data, published estimates of vegetative cover, and published estimates of transpiration rates we present estimates of the range of vegetative water demand and the change in water demand as influenced by changes in vegetation distribution through time.

  3. Classification of the ecological quality of the Aysen and Baker Fjords (Patagonia, Chile) using biotic indices.

    Science.gov (United States)

    Quiroga, Eduardo; Ortiz, Paula; Reid, Brian; Gerdes, Dieter

    2013-03-15

    The AZTI's marine biotic index (AMBI), an ecological indicator for managing estuarine and coastal waters worldwide, was tested in two fjords in Chilean Patagonia. The Aysen Fjord (42° Lat. S) supports intensive salmon farming in coastal ecosystems, while the Baker Fjord (48° Lat. S) is currently just beyond the limit of the southern expansion of salmon concessions. The ecological status of the Aysen Fjord was classified as good, while the status of the Baker Fjord was classified as high and unbalanced. These differences were consistent with our expectations, illustrating the effect of local environmental conditions and human activities, combined with river inputs into semi-confined fjords. This method is appropriate for the evaluation of the ecological status of the fjords, but requires a sufficient amount of data for the robust environmental assessment as proposed by the Water Framework Directive (WFD). Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Relationship of Melatonin and Salicylic Acid in Biotic/Abiotic Plant Stress Responses

    Directory of Open Access Journals (Sweden)

    Josefa Hernández-Ruiz

    2018-03-01

    Full Text Available Melatonin (N-acetyl-5-methoxytryptamine was discovered in plants in 1995, while salicylic acid was the name given to the active ingredient of willow in 1838. From a physiological point of view, these two molecules present in plants have never been compared, even though they have a great number of similarities, as we shall see in this work. Both molecules have biosynthesis pathways that share a common precursor and both play a relevant role in the physiology of plants, especially in aspects related to biotic and abiotic stress. They have also been described as biostimulants of photosynthetic processes and productivity enhancers in agricultural crops. We review the coincident aspects of both molecules, and propose an action model, by which the relationship between these molecules and other agents and plant hormones can be studied.

  5. Contribution of fish community metrics to the index of biotic integrity in two Ozark rivers

    Science.gov (United States)

    Hoefs, Nancy J.; Boyle, Terence P.

    1992-01-01

    Flow regime, energy source, water quality, and habitat structure within stream systems play major roles in controlling the structure of resident fish communities (Gorman and Karr, 1978; Karr and Dudley, 1981; Schlosser, 1982). Based on the hypothesis that there are predictable relationships between stream variables and fish community structure, overall stream condition has been assessed using indices such as the Index of Biotic Integrity (IBI) (Karr, 1981; Karr et al., 1986). The IBI integrates a wide range of information pertaining to fish community structure that reflects the prevailing chemical, physical, and biological condition of the stream. Assessments made using the IBI have been correlated to actual stream conditions and appear to be sensitive to a wide range of environmental degradation (Fausch et al., 1990).

  6. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

    Science.gov (United States)

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-03-01

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2.

  7. ROLE OF ABIOTIC AND BIOTIC FACTORS IN RESEARCH OF VARIETES OF WEIGELA (WEIGELA THUNB., CAPRIFOLIACEAE

    Directory of Open Access Journals (Sweden)

    A. V. Savenko

    2015-01-01

    Full Text Available Aim. The success of the introduction of plants depends on their vitality and adaptation to the new conditions of existence. The aim of our study is to identify environmental characteristics of varieties of Weigela to extend the range of ornamental plants under urban ecosystem of Krasnodar. We have analyzed the tolerance of varieties of Weigela to the temperature regime in the introduction region, we explored the complex biotic factors influencing the growth and development of these plants, and also studied the morphological characteristics of pollen and pollen productivity of Weigela flowers.Methods. Evaluation of resistance of varieties of Weigela to a complex of abiotic and biotic factors has been conducted in the field and in the laboratory, taking into account recommendations for ornamental shrubs.Results. Studied Weigela varieties have enough ecological valence to the force of impact of the maximum and minimum air temperatures in the area of the introduction. The most resistant to the complex of summer stress factors are the following varieties of Weigela: 'Candida', 'Nana Variegata', 'Olimpik Flame', 'Red Rrince'. The most heat-resistant varieties are 'Nana Variegata' and 'Olimpik Flame'. The most winter-hardy varieties are 'Candida' and 'Red Rrince', less winter-hardy variety is 'Nana Purpurea'. The most cold-resistant variety is 'Candida'. 'Nana Variegata' produces the highest number of fertile pollen grains. The smallest amount of fertile pollen is formed by 'Nana Purpurea'.Main conclusion. These studies allow us to conclude that all the studied varieties of Weigela are characterized by a high degree of adaptation and deserve widespread use in gardens and parks of the city of Krasnodar.

  8. Can we trace biotic dispersals back in time? Introducing backward flow connectivity

    Directory of Open Access Journals (Sweden)

    Alessandro Ferrarini

    2014-06-01

    Full Text Available Connectivity in ecology deals with the problem of how species dispersal will happen given actual landscape and species presence/absence over such landscape. Hence it can be considered a forward (ahead in time scientific problem. I observe here that a backward theory of connectivity could be of deep interest as well: given the actual species presence/absence on the landscape, where with the highest probability such species is coming from? In other words, can we trace biotic dispersals back in time? Recently I have introduced a modelling and theoretical approach to ecological connectivity that is alternative to circuit theory and is able to fix the weak point of the "from-to" connectivity approach. The proposed approach holds also for mountain and hilly landscapes. In addition, it doesn't assume any intention for a species to go from source points to sink ones, because the expected path for the species is determined locally (pixel by pixel by landscape features. In this paper, I introduce a new theoretical and modelling approach called "backward flow connectivity". While flow connectivity predicts future species dispersal by minimizing at each step the potential energy due to fictional gravity over a frictional landscape, backward flow connectivity does exactly the opposite, i.e. maximizes potential energy at each step sending back the species to higher levels of potential energy due to fictional gravity on the frictional landscape. Using backward flow connectivity, one has at hand a new tool to revert timeline of species dispersal, hence being able to trace backward biotic dispersals. With few modifications, the applications of backward flow connectivity can be countless, for instance tracing back-in-time not only plants and animals but also ancient human migrations and viral paths.

  9. Development of a Wireless Computer Vision Instrument to Detect Biotic Stress in Wheat

    Directory of Open Access Journals (Sweden)

    Joaquin J. Casanova

    2014-09-01

    Full Text Available Knowledge of crop abiotic and biotic stress is important for optimal irrigation management. While spectral reflectance and infrared thermometry provide a means to quantify crop stress remotely, these measurements can be cumbersome. Computer vision offers an inexpensive way to remotely detect crop stress independent of vegetation cover. This paper presents a technique using computer vision to detect disease stress in wheat. Digital images of differentially stressed wheat were segmented into soil and vegetation pixels using expectation maximization (EM. In the first season, the algorithm to segment vegetation from soil and distinguish between healthy and stressed wheat was developed and tested using digital images taken in the field and later processed on a desktop computer. In the second season, a wireless camera with near real-time computer vision capabilities was tested in conjunction with the conventional camera and desktop computer. For wheat irrigated at different levels and inoculated with wheat streak mosaic virus (WSMV, vegetation hue determined by the EM algorithm showed significant effects from irrigation level and infection. Unstressed wheat had a higher hue (118.32 than stressed wheat (111.34. In the second season, the hue and cover measured by the wireless computer vision sensor showed significant effects from infection (p = 0.0014, as did the conventional camera (p < 0.0001. Vegetation hue obtained through a wireless computer vision system in this study is a viable option for determining biotic crop stress in irrigation scheduling. Such a low-cost system could be suitable for use in the field in automated irrigation scheduling applications.

  10. Spatio-temporal patterns of tree establishment are indicative of biotic interactions during early invasion of a montane meadow

    Science.gov (United States)

    J.M. Rice; C.B. Halpern; J.A. Antos; J.A. Jones

    2012-01-01

    Tree invasions of grasslands are occurring globally, with profound consequences for ecosystem structure and function. We explore the spatio-temporal dynamics of tree invasion of a montane meadow in the Cascade Mountains of Oregon, where meadow loss is a conservation concern. We examine the early stages of invasion, where extrinsic and intrinsic processes can be clearly...

  11. Meta-analysis of field scale spatial variability of grassland soil CO2 efflux: Interaction of biotic and abiotic drivers

    Czech Academy of Sciences Publication Activity Database

    Fóti, S.; Balogh, J.; Herbst, M.; Papp, M.; Koncz, P.; Bartha, S.; Zimmermann, Z.; Komoly, C.; Szabó, G.; Margóczi, G.; Acosta, Manuel; Nagy, Z.

    2016-01-01

    Roč. 143, aug (2016), s. 78-89 ISSN 0341-8162 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Cross-variogram * Principal component analysis * Soil CO2 efflux * Spatial pattern * Variogram Subject RIV: EH - Ecology, Behaviour Impact factor: 3.191, year: 2016

  12. Biotic and Abiotic Interactions of Deep-Sea Hydrothermal Vent-Endemic Fish on the East Pacific Rise

    Science.gov (United States)

    2009-09-01

    has been suggested that lithium incorporation into otoliths may be increased when Li:Ca environmental ratios are low ( Milton and Chenery, 2001), yet...365-382. Milton DA, Chenery SR (2001) Sources and uptake of trace metals in otoliths of juvenile barramundi (Lates calcarifer). J Exp Mar Biol Ecol...Costa V, Martins I, Santos RS, Powell JJ (2005) Enrichment in trace metals (Al, Mn, Co, Cu, Mo, Cd, Fe, Zn, Pb, and Hg) of macro-invertebrate habitats at

  13. Biotic development comparisons of a wetland constructed to treat mine water drainage with a natural wetland system

    International Nuclear Information System (INIS)

    Webster, H.J.; Hummer, J.W.; Lacki, M.J.

    1994-01-01

    Using 5-yr of baseline data from a constructed wetland, the authors compared the biotic changes in this wetland to conditions in a natural wetland to determine if biotic development patterns were similar. The constructed wetland was built in 1985 to treat a coal mine discharge and was planted with broadleaf cattail (Typha latifolia) within the three-cell, 0.26 ha wetland. Species richness in permanent quadrants of the constructed wetland declined over the study period, while cattail coverage increased. Plant species composition diversified at the edges, with several species becoming established. The constructed wetland deepened and expanded slightly in area coverage during the study period. The constructed wetland supported herptofaunal communities that appeared more stable through time than those of the natural wetland and sustained a rudimentary food chain dependent upon autotrophic algal populations. Despite fundamental differences in substrate base, morphology, and water flow patterns, biotic trends for the constructed wetland coincided with succession-like patterns at the natural wetland. They suggest that further shifts in the biotic composition of the constructed wetland are likely, but the system should continue to persist if primary production meets or exceeds the microbial metabolic requirements necessary to treat mine drainage

  14. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal: Phase 2, Final report

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Kennedy, W.E. Jr.; Prohammer, L.A.; Simmons, M.A.

    1986-11-01

    The results reported here establish the relevance and propose a method for including biotic transport in the assessment and licensing process for commercial low-level waste disposal sites. Earlier work identified the biotic transport mechanisms and process scenarios linking biotic transport with dose to man, and developed models for assessment of impacts. Model modification and improvement efforts in enhancing the ability to represent soil erosion and soil transport within the trench cover. Two alternative hypotheses on plant root uptake were incorporated into the model to represent transport of radionuclides by roots that penetrate the buried waste. Enhancements were also made to the scenario for future site intruder activities. Representation of waste package decomposition in the model was confirmed as the best available alternative. Results from sensitivity analyses indicate that additional information is needed to evaluate the alternative hypotheses for plant root uptake of buried wastes. Site-specific evaluations of the contribution from biotic transport to the potential dose to man establish the relevance in the assessment process. The BIOPORT/MAXI1 computer software package is proposed for dose assessments of commercial low-level waste disposal sites

  15. Climatic and biotic changes around the Carboniferous/Permian boundary recorded in the continental basins of the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Opluštil, S.; Šimůnek, Z.; Zajíc, Jaroslav; Mencl, V.

    2013-01-01

    Roč. 119, č. 1 (2013), s. 114-151 ISSN 0166-5162 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : biotic change * Bohemian Massif * Carboniferous-Permian transition * continental basin Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.313, year: 2013

  16. Exploring the genetics underlying the responses to consecutive combinations of biotic stresses and drought in Arabidopsis thaliana

    NARCIS (Netherlands)

    Huang, Pingping

    2016-01-01

    Plants growing in natural environments are exposed to a broad range of biotic (pathogen attack, insect herbivory, etc.) and abiotic factors (drought, extreme temperatures, UV radiation, salinity, etc.) that are known to cause stress symptoms in many species (Pareek et al., 2010; Robert-Seilaniantz

  17. Cross-tolerance to biotic and abiotic stresses in plants: a focus on resistance to aphid infestation.

    Science.gov (United States)

    Foyer, Christine H; Rasool, Brwa; Davey, Jack W; Hancock, Robert D

    2016-03-01

    Plants co-evolved with an enormous variety of microbial pathogens and insect herbivores under daily and seasonal variations in abiotic environmental conditions. Hence, plant cells display a high capacity to respond to diverse stresses through a flexible and finely balanced response network that involves components such as reduction-oxidation (redox) signalling pathways, stress hormones and growth regulators, as well as calcium and protein kinase cascades. Biotic and abiotic stress responses use common signals, pathways and triggers leading to cross-tolerance phenomena, whereby exposure to one type of stress can activate plant responses that facilitate tolerance to several different types of stress. While the acclimation mechanisms and adaptive responses that facilitate responses to single biotic and abiotic stresses have been extensively characterized, relatively little information is available on the dynamic aspects of combined biotic/abiotic stress response. In this review, we consider how the abiotic environment influences plant responses to attack by phloem-feeding aphids. Unravelling the signalling cascades that underpin cross-tolerance to biotic and abiotic stresses will allow the identification of new targets for increasing environmental resilience in crops. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Biotic and abiotic soil factors in the succession of sea buckthorn, Hippophae rhamnoides L. in coastal sand dunes

    NARCIS (Netherlands)

    Zoon, F.

    1995-01-01

    Decline and succession in dune scrub vegetation of sea buckthorn, Hippophaë rhamnoides L. in the Netherlands was previously found to be stimulated by biotic soil factors. In the present study, the role of plant-parasitic nematodes and root fungi was investigated. A

  19. A potential conflict between preserving regional plant diversity and biotic resistance to an invasive grass, Microstegium vimineum

    Science.gov (United States)

    J. Stephen Brewer

    2010-01-01

    The relevance of diversity-biotic resistance studies to conservation of biodiversity could be improved by simultaneously examining the drivers of regional diversity and their effects on local species diversity and invasion. Using path analysis, I examined direct and indirect effects of various abiotic factors (i.e., flooding, treefall gaps, soil texture, proximity to...

  20. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal: Phase 2, Final report

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, D.H.; Cadwell, L.L.; Kennedy, W.E. Jr.; Prohammer, L.A.; Simmons, M.A.

    1986-11-01

    The results reported here establish the relevance and propose a method for including biotic transport in the assessment and licensing process for commercial low-level waste disposal sites. Earlier work identified the biotic transport mechanisms and process scenarios linking biotic transport with dose to man, and developed models for assessment of impacts. Model modification and improvement efforts in enhancing the ability to represent soil erosion and soil transport within the trench cover. Two alternative hypotheses on plant root uptake were incorporated into the model to represent transport of radionuclides by roots that penetrate the buried waste. Enhancements were also made to the scenario for future site intruder activities. Representation of waste package decomposition in the model was confirmed as the best available alternative. Results from sensitivity analyses indicate that additional information is needed to evaluate the alternative hypotheses for plant root uptake of buried wastes. Site-specific evaluations of the contribution from biotic transport to the potential dose to man establish the relevance in the assessment process. The BIOPORT/MAXI1 computer software package is proposed for dose assessments of commercial low-level waste disposal sites.

  1. Utilizing genetic diversity in the desert watermelon citrullus colocynthis for enhancing watermelon cultivars for resistance to biotic and abiotic stress

    Science.gov (United States)

    Wide genetic diversity exists among the desert watermelon Citrullus colocynthis (L.) Schrad. (CC) accessions collected in the deserts of northern Africa, the Middle East, and Asia. Because of their resistance to biotic and abiotic stresses, there can be a viable source of genes used for enhancing wa...

  2. Using forest inventory and analysis data to understand biotic resistance to plant invasions across the Eastern United States

    Science.gov (United States)

    Basil V. III Iannone; Kevin M. Potter; Hao Zhang; Christopher M. Guo Oswalt; Christopher W. Woodall; Songlin. Fei

    2015-01-01

    Biological invasions and their impacts are likely to increase with the expansion of global commerce, making the need to identify key drivers and regulators of invasion perhaps greater than ever. One of the most enduring, and tested, hypotheses for explaining invasions is the “biotic resistance hypothesis.” Broadly, this hypothesis states that communities having greater...

  3. Mutualism and Antagonism: Ecological Interactions Among Bark Beetles, Mite and Fungi

    Science.gov (United States)

    K.D. Klepzig; J.C. Moser; M.J. Lombardero; M.P. Ayres; R.W. Hofstetter; C.J. Walkinshaw

    2001-01-01

    Insect-fungal complexes provide challenging and fascinating systems for the study of biotic interactions between plants. plant pathogens, insect vectors and other associated organisms. The types of interactions among these organisms (mutualism. antagonism. parasitism. phoresy. etc.) are as variable as the range of organisms involved (plants, fungi, insects. mites. etc...

  4. BIOTIC INTEGRITY OF STREAMS IN THE SAVANNAH RIVER SITE INTEGRATOR OPERABLE UNITS, 1996 TO 2003

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M; Susan Dyer, S

    2004-11-08

    The Savannah River Site (SRS) has been divided into six Integrator Operable Units (IOUs) that correspond to the watersheds of the five major streams on the SRS (Upper Three Runs, Fourmile Branch, Pen Branch, Steel Creek, and Lower Three Runs) and the portions of the Savannah River and Savannah River Swamp associated with the SRS. The streams are the primary integrators within each IOU because they potentially receive, through surface or subsurface drainage, soluble contaminants from all waste sites within their watersheds. If these contaminants reach biologically significant levels, they would be expected to effect the numbers, types, and health of stream organisms. In this study, biological sampling was conducted within each IOU as a measure of the cumulative ecological effects of the waste sites within the IOUs. The use of information from biological sampling to assess environmental quality is often termed bioassessment. The IOU bioassessment program included 38 sites in SRS streams and nine sites in the Savannah River. Sampling was conducted in 1996 to 1998, 2000, and 2003. Four bioassessment methods were used to evaluate ecological conditions in the IOU streams: the Index of Biotic Integrity, the Fish Health Assessment Index, measurement of fish tissue contaminant levels, and two benthic macroinvertebrate indices. The Index of Biotic Integrity (IBI) is an EPA supported method based on comparison of ecologically important and sensitive fish assemblage variables between potentially disturbed and reference (i.e., undisturbed) sites. It is designed to assess the ability of a stream to support a self-sustaining biological community and ecological processes typical of undisturbed, natural conditions. Since many types of contaminants can bioaccumulate, fish tissue contaminant data were used to determine the types of chemicals fish were exposed to and their relative magnitudes among IOUs. The Fish Health Assessment Index (HAI) is an EPA supported method for assessing

  5. Abiotic and Biotic Formation of Amino Acids in the Enceladus Ocean.

    Science.gov (United States)

    Steel, Elliot L; Davila, Alfonso; McKay, Christopher P

    2017-09-01

    The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H 2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H 2 production of 0.6-34 mol/s from serpentinization, sufficient to sustain abiotic and biotic amino acid synthesis of 1.6-87 and 1-44 g/s, respectively. Two-dimensional (2D) numerical simulations of the hydrothermal vent suggest that the vent fluids could reach the ice-water boundary in less than 11-55 days for a 50 km deep ocean diluted by ambient ocean water 10 to 1. Concentrations of glycine, alanine, α-amino isobutyric acid, and glutamic acid in the plume and in the ambient ocean could all be above 0.01 μM just due to abiotic production. Biological synthesis, if occurring, could produce a maximum of 90 μM concentrations of amino acids based on a methanogenic ecosystem consuming H 2 and CO 2 . Racemization timescales in the ocean are short compared with production timescales. Thus, no enantiomeric excess is expected in the ambient ocean, and if biology is present, enantiomeric excess at the vent fluids is expected to be less than 10% in the plume. From vent H 2 concentrations of 7.8 mM (e.g., Lost City) and assuming complete H 2 use and conversion to chemical energy by methanogens, cell production is estimated. Annual biomass production in the methanogenic-based biology model is 4 × 10 4 -2 × 10 6 kg/year. This corresponds to cell concentrations ∼10 9 cells/cm 3 in the vents and ∼10 8 cells/cm 3 in the plume, and when diluted into the ambient ocean, we predict cell concentrations of 80-4250 cells/cm 3 . Key Words: Abiotic organic

  6. Effect of biotic lignin decomposition on the fate of radiocesium-contaminated plant litter

    Energy Technology Data Exchange (ETDEWEB)

    Hashida, Shin-nosuke; Yoshihara, Toshihiro [Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko 1646, Abiko-shi, Chiba (Japan)

    2014-07-01

    Fungi are the most important components in the fate of radionuclides deposited in forests following the Fukushima nuclear accident. Pruned woody parts and litter contain a considerable amount of radiocesium. Studies that focused on the migration of radiocesium have demonstrated that its ecological half-life is lower in the humus layer than in the deeper soil zone, suggesting a substantial contribution of litter decomposition on the mobilization of radiocesium. Furthermore, white-rot fungi appear to play a key role in the mobilization of radiocesium because they are the primary source of enzymes necessary to degrade the litter organic matter. Cell walls are the primary component of plant litter; they are composed of cellulose, hemi-cellulose, and lignin. Although cellulose is the most abundant organic compound in litter, the strength of the cell wall is limited by rigid hemi-cellulose complexes that protect the surrounding cellulose microfibrils. In the cell wall, lignin fills the spaces between cellulose and hemi-cellulose; thus, the biotic degradation of lignin could be considered a primary step in litter decomposition. The contribution of the amount of lignin on the fate of radiocesium has not been identified, which limits the possibility of predicting the effect of the bacterial community structure that determines the biodegradation activity of lignin on the vertical migration of radiocesium. Here, we directly addressed the role of lignin as controller of the distribution of radiocesium in soil-ecosystems. Radiocesium-contaminated litter samples were collected with traps set under the target stands, i.e., Japanese flowering cherry trees (Prunus x yedoensis cv. Somei-Yoshino) and Japanese cedars (Cryptomeria japonica) at Abiko (Laboratory of Environmental Science, CRIEPI) located approximately 200 km SSW from the Fukushima Daiichi Nuclear Power Plant in 2011. The litter samples were inoculated with white-rot fungi having ligno-celluloses-degrading activity, i

  7. An Index of Biotic Integrity for shallow streams of the Hondo River basin, Yucatan Peninsula

    International Nuclear Information System (INIS)

    Schmitter-Soto, Juan J.; Ruiz-Cauich, Lissie E.; Herrera, Roberto L.; Gonzalez-Solis, David

    2011-01-01

    An Index of Biotic Integrity (IBI) is proposed, based on the fish communities and populations in streams of the Hondo River basin, Mexico-Belize. Freshwater environments in this area are threatened by exotic fishes, eutrophication, and pesticide pollution, among other problems. This IBI should allow to identify the most vulnerable sites and eventually guide rehabilitation efforts. Data on composition, structure, and function of fish communities were evaluated. Twenty-three sites in the Mexican part of the basin were explored; a stratified sample of 13 sites was used to design the IBI, and the rest were used to test and refine the index. Thirty-four candidate indicator metrics were scanned for their correlation with an index of water and habitat quality (IWHQ), as well as for the possible influence of stream width and altitude or distance to the Hondo River mainstem. Twelve variables were selected to constitute the IBI: relative abundances of Astyanax aeneus, 'Cichlasoma' urophthalmus, Poecilia mexicana, Poecilia sp. (a new species, probably endemic to the upper Hondo River basin), Xiphophorus hellerii, and X. maculatus; relative abundances of bentholimnetic, herbivore, and sensitive species; percentage of native and tolerant species; and Pielou's evenness index. Most of the sites have a low-medium quality and integrity, showing impact due to partial channelization or to suboptimal water quality, reflected in scarcity or absence of sensitive species, frequent excess of tolerant species, occasional presence of exotics, dominance of herbivores (perhaps due to proliferation of filamentous algae), or dominance of the opportunistic species P. mexicana. The streams with better water and habitat quality are those farthest away from the river mainstem, probably because of lower human population and economical production. - Research Highlights: → An Index of Biotic Integrity based on fishes is proposed for streams of the Hondo River basin. → Twelve variables were

  8. Incorporating bioavailability into toxicity assessment of Cu-Ni, Cu-Cd, and Ni-Cd mixtures with the extended biotic ligand model and the WHAM-F(tox) approach.

    Science.gov (United States)

    Qiu, Hao; Vijver, Martina G; He, Erkai; Liu, Yang; Wang, Peng; Xia, Bing; Smolders, Erik; Versieren, Liske; Peijnenburg, Willie J G M

    2015-12-01

    There are only a limited number of studies that have developed appropriate models which incorporate bioavailability to estimate mixture toxicity. Here, we explored the applicability of the extended biotic ligand model (BLM) and the WHAM-F(tox) approach for predicting and interpreting mixture toxicity, with the assumption that interactions between metal ions obey the BLM theory. Seedlings of lettuce Lactuca sativa were exposed to metal mixtures (Cu-Ni, Cu-Cd, and Ni-Cd) contained in hydroponic solutions for 4 days. Inhibition to root elongation was the endpoint used to quantify the toxic response. Assuming that metal ions compete with each other for binding at a single biotic ligand, the extended BLM succeeded in predicting toxicity of three mixtures to lettuce, with more than 82% of toxicity variation explained. There were no significant differences in the values of f(mix50) (i.e., the overall amounts of metal ions bound to the biotic ligand inducing 50% effect) for the three mixture combinations, showing the possibility of extrapolating these values to other binary metal combinations. The WHAM-F(tox) approach showed a similar level of precision in estimating mixture toxicity while requiring fewer parameters than the BLM-f(mix) model. External validation of the WHAM-F(tox) approach using literature data showed its applicability for other species and other mixtures. The WHAM-F(tox) model is suitable for delineating mixture effects where the extended BLM also applies. Therefore, in case of lower data availability, we recommend the lower parameterized WHAM-F(tox) as an effective approach to incorporate bioavailability in quantifying mixture toxicity.

  9. Development of a macrophyte-based index of biotic integrity for Minnesota lakes

    Science.gov (United States)

    Beck, M.W.; Hatch, L.K.; Vondracek, B.; Valley, R.D.

    2010-01-01

    Traditional approaches for managing aquatic resources have often failed to account for effects of anthropogenic disturbances on biota that are not directly reflected by chemical and physical proxies of environmental condition. The index of biotic integrity (IBI) is a potentially effective assessment method to integrate ecological, functional, and structural aspects of aquatic systems. A macrophyte-based IBI was developed for Minnesota lakes to assess the ability of aquatic plant communities to indicate environmental condition. The index was developed using quantitative point intercept vegetation surveys for 97 lakes that represent a range of limnological and watershed characteristics. We followed an approach similar to that used in Wisconsin to develop the aquatic macrophyte community index (AMCI). Regional adaptation of the AMCI required the identification of species representative of macrophyte communities in Minnesota. Metrics and scaling methods were also substantially modified to produce a more empirically robust index. Regression analyses indicated that IBI scores reflected statewide differences in lake trophic state (R2 = 0.57, F = 130.3, df = 1, 95, p indicated a unique response of the IBI to human-induced stress separate from a response to natural lake characteristics. The IBI was minimally affected by differences in sample point density as indicated by Monte Carlo analyses of reduced sampling effort. Our analysis indicates that a macrophyte IBI calibrated for Minnesota lakes could be useful for identifying differences in environmental condition attributed to human-induced stress gradients. ?? 2010 Elsevier Ltd.

  10. At limits of life: multidisciplinary insights reveal environmental constraints on biotic diversity in continental Antarctica.

    Science.gov (United States)

    Magalhães, Catarina; Stevens, Mark I; Cary, S Craig; Ball, Becky A; Storey, Bryan C; Wall, Diana H; Türk, Roman; Ruprecht, Ulrike

    2012-01-01

    Multitrophic communities that maintain the functionality of the extreme Antarctic terrestrial ecosystems, while the simplest of any natural community, are still challenging our knowledge about the limits to life on earth. In this study, we describe and interpret the linkage between the diversity of different trophic level communities to the geological morphology and soil geochemistry in the remote Transantarctic Mountains (Darwin Mountains, 80°S). We examined the distribution and diversity of biota (bacteria, cyanobacteria, lichens, algae, invertebrates) with respect to elevation, age of glacial drift sheets, and soil physicochemistry. Results showed an abiotic spatial gradient with respect to the diversity of the organisms across different trophic levels. More complex communities, in terms of trophic level diversity, were related to the weakly developed younger drifts (Hatherton and Britannia) with higher soil C/N ratio and lower total soluble salts content (thus lower conductivity). Our results indicate that an increase of ion concentration from younger to older drift regions drives a succession of complex to more simple communities, in terms of number of trophic levels and diversity within each group of organisms analysed. This study revealed that integrating diversity across multi-trophic levels of biotic communities with abiotic spatial heterogeneity and geological history is fundamental to understand environmental constraints influencing biological distribution in Antarctic soil ecosystems.

  11. At limits of life: multidisciplinary insights reveal environmental constraints on biotic diversity in continental Antarctica.

    Directory of Open Access Journals (Sweden)

    Catarina Magalhães

    Full Text Available Multitrophic communities that maintain the functionality of the extreme Antarctic terrestrial ecosystems, while the simplest of any natural community, are still challenging our knowledge about the limits to life on earth. In this study, we describe and interpret the linkage between the diversity of different trophic level communities to the geological morphology and soil geochemistry in the remote Transantarctic Mountains (Darwin Mountains, 80°S. We examined the distribution and diversity of biota (bacteria, cyanobacteria, lichens, algae, invertebrates with respect to elevation, age of glacial drift sheets, and soil physicochemistry. Results showed an abiotic spatial gradient with respect to the diversity of the organisms across different trophic levels. More complex communities, in terms of trophic level diversity, were related to the weakly developed younger drifts (Hatherton and Britannia with higher soil C/N ratio and lower total soluble salts content (thus lower conductivity. Our results indicate that an increase of ion concentration from younger to older drift regions drives a succession of complex to more simple communities, in terms of number of trophic levels and diversity within each group of organisms analysed. This study revealed that integrating diversity across multi-trophic levels of biotic communities with abiotic spatial heterogeneity and geological history is fundamental to understand environmental constraints influencing biological distribution in Antarctic soil ecosystems.

  12. Geochemical evidence for a catastrophic biotic event at the Frasnian/Famennian boundary in south China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kun; Chatterton, B.D.E. (Univ. of Alberta, Edmonton (Canada)); Orth, C.J.; Attrep, M. Jr. (Los Alamos National Lab., NM (United States)); Hongfei Hou (Chinese Academy of Geological Sciences, Beijing (China)); Geldsetzer, H.H.J. (Geological Survey of Canada, Alberta (United States))

    1991-08-01

    A strong {delta}{sup 13}C anomaly coincides with a weak Ir anomaly at the Frasnian/Famennian (F/F) boundary exposed at Xiangtian, Guangxi, south China. The maximum whole-rock Ir abundance is 0.23 ppb (0.35 ppb on a carbonate-free basis) compared with averages of 0.016 and 0.044 ppb above and below the boundary interval. The {delta}{sup 13}C in carbonate abruptly shifts from a late Frasnian level of about +1{per thousand} to {minus}2.49 {per thousand}in the boundary interval and then abruptly returns to pre-boundary levels, suggesting a temporary reduction of surface-water biomass. A widely distributed (over at least several hundred kilometers) limestone breccia unit of possible wave-deposit origin is present directly below the boundary in south China. Enrichments of Al, V, Cr, As, and U, and a dip in the Mn abundance in the boundary interval indicate that reducing conditions might have been associated with the element enrichment. However, an alternative hypothesis is that oceanic impact(s) at the F/F boundary near south China provided the excess Ir and caused the biotic crisis and the formation of breccia deposits observed in the Late Devonian South China Sea.

  13. Simulated 21st century's increase in oceanic suboxia by CO2-enhanced biotic carbon export

    Science.gov (United States)

    Oschlies, Andreas; Schulz, Kai G.; Riebesell, Ulf; Schmittner, Andreas

    2008-12-01

    The primary impacts of anthropogenic CO2 emissions on marine biogeochemical cycles predicted so far include ocean acidification, global warming induced shifts in biogeographical provinces, and a possible negative feedback on atmospheric CO2 levels by CO2-fertilized biological production. Here we report a new potentially significant impact on the oxygen-minimum zones of the tropical oceans. Using a model of global climate, ocean circulation, and biogeochemical cycling, we extrapolate mesocosm-derived experimental findings of a pCO2-sensitive increase in biotic carbon-to-nitrogen drawdown to the global ocean. For a simulation run from the onset of the industrial revolution until A.D. 2100 under a "business-as-usual" scenario for anthropogenic CO2 emissions, our model predicts a negative feedback on atmospheric CO2 levels, which amounts to 34 Gt C by the end of this century. While this represents a small alteration of the anthropogenic perturbation of the carbon cycle, the model results reveal a dramatic 50% increase in the suboxic water volume by the end of this century in response to the respiration of excess organic carbon formed at higher CO2 levels. This is a significant expansion of the marine "dead zones" with severe implications not only for all higher life forms but also for oxygen-sensitive nutrient recycling and, hence, for oceanic nutrient inventories.

  14. Abiotic and biotic transformations of 1,1,1-trichloroethane under methanogenic conditions

    International Nuclear Information System (INIS)

    Vogel, T.M.; McCarty, P.L.

    1987-01-01

    A common industrial solvent, 1,1,1-trichloroethane (TCA), is one of the most frequently found contaminants in ground water. The fate of TCA in ground water is complicated by the different possible abiotic and biotic transformations that it may undergo. Abiotic transformation of TCA can result in a mixture of 1,1-dichloro-ethylene (1,1-DCE) and acetic acid, as shown by others. This study confirms that TCA can be biotransformed by reductive dehalogenation to 1,1-dichloroethane (1,1-DCA) and chloroethane (CA) under methanogenic conditions. Also, reductive dehalogenation of 1,1-DCE to vinyl chloride (VC) is confirmed. This study demonstrates that these transformations can occur stoichiometrically. In addition, [ 14 C]TCA, [ 14 C]-1,1-DCA, [ 14 C]-1,1-DCE, [ 14 C]CA, and [ 14 C]VC were at least partially mineralized to 14 CO 2 under similar methanogenic conditions.23 references, 3 figures, 4 tables

  15. Application of Biotic Ligand Model in Predicting Copper Acute Toxicity to Carp (Cyprinidae).

    Science.gov (United States)

    Wang, Wanbin; Liang, Qibin; Zhao, Jing; Chen, Rui

    2017-01-01

    Three representative species of Cyprinidae fishes (Aristichthys nobilis, Ctenopharyngodon idellus, and Cyprinus carpio), which are abundant in Chinese surface waters, were studied to determine their sensitivity to copper (Cu) in acute exposures. We first performed acute toxicity tests to determine the Cu LC 50 value for each species in water with varying characteristics. The biotic ligand model (BLM) was then calibrated using the toxicity data for these species together with binding properties specific to Cu. The BLM calibration involved the calculation of the level of Cu accumulation in the gills that resulted in 50% lethality (i.e., LA 50 ). The LA 50 values for A. nobilis, C. idellus and C. carpio were 5.16, 11.60 and 9.00 nmol g -1 . The model calibrated to these data was improved by adjusting the Cu-proton exchange constant (pK CuHA-A ) and dissolved organic carbon (DOC) to values of 1.84 and 4.67E-3 mol g -1 , respectively. The calibrated Cu-BLM was validated for these three common fish species by comparing predicted and observed LC 50 values, which were in agreement to within a factor of 2. The results of this study provide an important contribution to ecological risk assessment and establishment of water quality criteria for Cu in China.

  16. Biotic and abiotic variables influencing plant litter breakdown in streams: a global study

    Science.gov (United States)

    Pearson, Richard G.; Hui, Cang; Gessner, Mark O.; Pérez, Javier; Alexandrou, Markos A.; Graça, Manuel A. S.; Cardinale, Bradley J.; Albariño, Ricardo J.; Arunachalam, Muthukumarasamy; Barmuta, Leon A.; Boulton, Andrew J.; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G.; Dudgeon, David; Encalada, Andrea C.; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S.; Gonçalves, José F.; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S.; Pringle, Catherine M.; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M.

    2016-01-01

    Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons. PMID:27122551

  17. Slowed decomposition is biotically mediated in an ectomycorrhizal, tropical rain forest.

    Science.gov (United States)

    McGuire, Krista L; Zak, Donald R; Edwards, Ivan P; Blackwood, Christopher B; Upchurch, Rima

    2010-11-01

    Bacteria and fungi drive the cycling of plant litter in forests, but little is known about their role in tropical rain forest nutrient cycling, despite the high rates of litter decay observed in these ecosystems. However, litter decay rates are not uniform across tropical rain forests. For example, decomposition can differ dramatically over small spatial scales between low-diversity, monodominant rain forests, and species-rich, mixed forests. Because the climatic patterns and soil parent material are identical in co-occurring mixed and monodominant forests, differences in forest floor accumulation, litter production, and decomposition between these forests may be biotically mediated. To test this hypothesis, we conducted field and laboratory studies in a monodominant rain forest in which the ectomycorrhizal tree Dicymbe corymbosa forms >80% of the canopy, and a diverse, mixed forest dominated by arbuscular mycorrhizal trees. After 2 years, decomposition was significantly slower in the monodominant forest (P forest (P forest (P = 0.02), and the composition of fungal communities was distinct between the two rain forest types (P = 0.001). Sequencing of fungal rDNA revealed a significantly lower richness of saprotrophic fungi in the monodominant forest (19 species) relative to the species-rich forest (84 species); moreover, only 4% percent of fungal sequences occurred in both forests. These results show that nutrient cycling patterns in tropical forests can vary dramatically over small spatial scales, and that changes in microbial community structure likely drive the observed differences in decomposition.

  18. Persistent Organic Pollutants in Biotic and Abiotic Components of Antarctic Pristine Environment

    Science.gov (United States)

    Bhardwaj, Laxmikant; Chauhan, Abhishek; Ranjan, Anuj; Jindal, Tanu

    2018-02-01

    Over the past decades, research in Antarctica has built a new understanding of Antarctica, its past, present and future. Human activities and long-range pollutants are increasing on the Antarctic continent. Research on persistent organic pollutants (POPs) has been carried out internationally by several countries having their permanent research stations to explain the impact of an ever increasing range of POPs in Antarctic ecosystem. POPs have been detected in Antarctica despite its geographical isolation and almost complete absence of human settlements. The presence of POPs in different abiotic (atmosphere, water bodies, sediments, soil, sea ice) and biotic components (mosses, lichens, krill, penguins, skua, etc.) in Antarctica has been studied and documented around for decades and has either been banned or strictly regulated but is still found in the environment. This review focuses on recent research pertaining to sources and occurrence of POPs in Antarctic lake water, soil, sediment, lichen, mosses and other Antarctic marine community. This review also proposes to summarize the current state of research on POPs in Antarctica environment and draw the earliest conclusions on possible significance of POPs in Antarctica based on presently available information from related Antarctic environment.

  19. Biotic and abiotic variables influencing plant litter breakdown in streams: a global study.

    Science.gov (United States)

    Boyero, Luz; Pearson, Richard G; Hui, Cang; Gessner, Mark O; Pérez, Javier; Alexandrou, Markos A; Graça, Manuel A S; Cardinale, Bradley J; Albariño, Ricardo J; Arunachalam, Muthukumarasamy; Barmuta, Leon A; Boulton, Andrew J; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G; Dudgeon, David; Encalada, Andrea C; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S; Gonçalves, José F; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S; Pringle, Catherine M; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M

    2016-04-27

    Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons. © 2016 The Author(s).

  20. Development of a wireless computer vision instrument to detect biotic stress in wheat.

    Science.gov (United States)

    Casanova, Joaquin J; O'Shaughnessy, Susan A; Evett, Steven R; Rush, Charles M

    2014-09-23

    Knowledge of crop abiotic and biotic stress is important for optimal irrigation management. While spectral reflectance and infrared thermometry provide a means to quantify crop stress remotely, these measurements can be cumbersome. Computer vision offers an inexpensive way to remotely detect crop stress independent of vegetation cover. This paper presents a technique using computer vision to detect disease stress in wheat. Digital images of differentially stressed wheat were segmented into soil and vegetation pixels using expectation maximization (EM). In the first season, the algorithm to segment vegetation from soil and distinguish between healthy and stressed wheat was developed and tested using digital images taken in the field and later processed on a desktop computer. In the second season, a wireless camera with near real-time computer vision capabilities was tested in conjunction with the conventional camera and desktop computer. For wheat irrigated at different levels and inoculated with wheat streak mosaic virus (WSMV), vegetation hue determined by the EM algorithm showed significant effects from irrigation level and infection. Unstressed wheat had a higher hue (118.32) than stressed wheat (111.34). In the second season, the hue and cover measured by the wireless computer vision sensor showed significant effects from infection (p = 0.0014), as did the conventional camera (p irrigation scheduling. Such a low-cost system could be suitable for use in the field in automated irrigation scheduling applications.

  1. Environmental and biotic correlates to lionfish invasion success in Bahamian coral reefs.

    Directory of Open Access Journals (Sweden)

    Andrea Anton

    Full Text Available Lionfish (Pterois volitans, venomous predators from the Indo-Pacific, are recent invaders of the Caribbean Basin and southeastern coast of North America. Quantification of invasive lionfish abundances, along with potentially important physical and biological environmental characteristics, permitted inferences about the invasion process of reefs on the island of San Salvador in the Bahamas. Environmental wave-exposure had a large influence on lionfish abundance, which was more than 20 and 120 times greater for density and biomass respectively at sheltered sites as compared with wave-exposed environments. Our measurements of topographic complexity of the reefs revealed that lionfish abundance was not driven by habitat rugosity. Lionfish abundance was not negatively affected by the abundance of large native predators (or large native groupers and was also unrelated to the abundance of medium prey fishes (total length of 5-10 cm. These relationships suggest that (1 higher-energy environments may impose intrinsic resistance against lionfish invasion, (2 habitat complexity may not facilitate the lionfish invasion process, (3 predation or competition by native fishes may not provide biotic resistance against lionfish invasion, and (4 abundant prey fish might not facilitate lionfish invasion success. The relatively low biomass of large grouper on this island could explain our failure to detect suppression of lionfish abundance and we encourage continuing the preservation and restoration of potential lionfish predators in the Caribbean. In addition, energetic environments might exert direct or indirect resistance to the lionfish proliferation, providing native fish populations with essential refuges.

  2. Robust RNA silencing-mediated resistance to Plum pox virus under variable abiotic and biotic conditions.

    Science.gov (United States)

    Di Nicola, Elisa; Tavazza, Mario; Lucioli, Alessandra; Salandri, Laura; Ilardi, Vincenza

    2014-10-01

    Some abiotic and biotic conditions are known to have a negative impact on post-transcriptional gene silencing (PTGS), thus representing a potential concern for the production of stable engineered virus resistance traits. However, depending on the strategy followed to achieve PTGS of the transgene, different responses to external conditions can be expected. In the present study, we utilized the Nicotiana benthamiana–Plum pox virus (PPV) pathosystem to evaluate in detail the stability of intron-hairpin(ihp)-mediated virus resistance under conditions known to adversely affect PTGS. The ihp plants grown at low or high temperatures were fully resistant to multiple PPV challenges, different PPV inoculum concentrations and even to a PPV isolate differing from the ihp construct by more than 28% at the nucleotide level. In addition, infections of ihp plants with viruses belonging to Cucumovirus, Potyvirus or Tombusvirus, all known to affect PTGS at different steps, were not able to defeat PPV resistance. Low temperatures did not affect the accumulation of transgenic small interfering RNAs (siRNAs), whereas a clear increase in the amount of siRNAs was observed during infections sustained by Cucumber mosaic virus and Potato virus Y. Our results show that the above stress factors do not represent an important concern for the production,through ihp-PTGS technology, of transgenic plants having robust virus resistance traits.

  3. Macrophytes, epipelic biofilm, and invertebrates as biotic indicators of physical habitat degradation of lowland streams (Argentina).

    Science.gov (United States)

    Cortelezzi, Agustina; Sierra, María Victoria; Gómez, Nora; Marinelli, Claudia; Rodrigues Capítulo, Alberto

    2013-07-01

    Our objective was to assess the effect of the physical habitat degradation in three lowland streams of Argentina that are subject to different land uses. To address this matter, we looked into some physical habitat alterations, mainly the water quality and channel changes, the impact on macrophytes' community, and the structural and functional descriptors of the epipelic biofilm and invertebrate assemblages. As a consequence of physical and chemical perturbations, we differentiated sampling sites with different degradation levels. The low degraded sites were affected mainly for the suburban land use, the moderately degraded sites for the rural land use, and the highly degraded sites for the urban land use. The data shows that the biotic descriptors that best reflected the environmental degradation were vegetation cover and macrophytes richness, the dominance of tolerant species (epipelic biofilm and invertebrates), algal biomass, O2 consumption by the epipelic biofilm, and invertebrates' richness and diversity. Furthermore, the results obtained highlight the importance of the macrophytes in the lowland streams, where there is a poor diversification of abiotic substrates and where the macrophytes not only provide shelter but also a food source for invertebrates and other trophic levels such as fish. We also noted that both in benthic communities, invertebrates and epipelic biofilm supplied different information: the habitat's physical structure provided by the macrophytes influenced mainly the invertebrate descriptors; meanwhile, the water quality mainly influenced most of the epipelic biofilm descriptors.

  4. IMPACT OF SMALL HYDROPOWER PLANTS ON PHYSICOCHEMICAL AND BIOTIC ENVIRONMENTS IN FLATLAND RIVERBEDS OF LITHUANIA

    Directory of Open Access Journals (Sweden)

    Saulius Vaikasas

    2015-02-01

    Full Text Available The impact of a small hydropower plant (SHP on river water quality and macroinvertebrates has been investigated in 5 Lithuanian rivers and involved 17 dams, ten of which are in a sequence in the same river system. The hydrostatic head of SHP dams ranged from 2.75 to 14.50 m and the capacities of their reservoirs varied from 40×103 to 15,500×103 m3. Physicochemical characteristics, as well as macroinvertebrate communities, were evaluated in sites above and below the SHP dams comparing them with reference sites. It was established that construction of SHP dams (H<15 m in Lithuania substantially changed regimes of suspended solids, fine particles and nutrients only locally regardless of hydrostatic head of the dam. Compared to reference sites, SHP reservoirs and sites below SHP dams had relatively more Chironomidae larvae and Oligochaeta, and less Coleoptera larvae as well as the relative abundance of pollution-sensitive Ephemeroptera and EPT. Water quality according to biotic indexes (DSFI and HBI in the sites influenced by SHP dams was recognised to be moderate or poor, but impact was only local. This suggests that increment of catchment’s area and intensive land use for agriculture within the river basin plays more important role than SHP dams.

  5. ANALYSIS OF BIOTIC AND ABIOTIC FACTORS INFLUENCING THE OCCURRENCE OF WEST NILE VIRUS INFECTION IN TUNISIA.

    Science.gov (United States)

    Ben Hassine, Th; Calistri, P; Ippoliti, C; Conte, A; Danzetta, M L; Bruno, R; Lelli, R; Bejaoui, M; Hammami, S

    2014-01-01

    Eco-climatic conditions are often associated with the occurrence of West Nile Disease (WND) cases. Among the complex set of biotic and abiotic factors influencing the emergence and spread of this vector-borne disease, two main variables have been considered to have a great influence on the probability of West Nile Virus (WNV) introduction and circulation in Tunisia: the presence of susceptible bird populations and the existence of geographical areas where the environmental and climatic conditions are more favourable to mosquito multiplications. The aim of this study was to identify and classify the climatic and environmental variables possibly associated with the occurrence of WNVhuman cases in Tunisia. The following environmental and climatic variables have been considered: wetlands and humid areas, Normalised Difference Vegetation Index (NDVI), temperatures and elevation. A preliminary analysis for the characterization of main variables associated with areas with a history of WNV human cases in Tunisia between 1997 and 2011 has been made. This preliminary analysis clearly indicates the closeness to marshes ecosystem, where migratory bird populations are located, as an important risk factor for WNV infection. On the contrary the temperature absolute seems to be not a significant factor in Tunisian epidemiological situation. In relation to NDVI values, more complex considerations should be made.

  6. Feeding in deep-sea demosponges: Influence of abiotic and biotic factors

    Science.gov (United States)

    Robertson, Leah M.; Hamel, Jean-François; Mercier, Annie

    2017-09-01

    In shallow benthic communities, sponges are widely recognized for their ability to contribute to food webs by cycling nutrients and mediating carbon fluxes through filter feeding. In comparison, little is known about filter feeding in deep-sea species and how it may be modulated by environmental conditions. Here, a rare opportunity to maintain live healthy deep-sea sponges for an extended period led to a preliminary experimental study of their feeding metrics. This work focused on demosponges collected from the continental slope of eastern Canada at 1000 m depth. Filtration rates (as clearance of phytoplankton cells) at holding temperature (6 °C) were positively correlated with food particle concentration, ranging on average from 18.8 to 160.6 cells ml-1 h-1 at nominal concentrations of 10,000-40,000 cells ml-1. Cell clearance was not significantly affected by decreasing seawater temperature, from 6 °C to 3 °C or 0 °C, although two of the sponges showed decreased filtration rates. Low pH ( 7.5) and the presence of a predatory sea star markedly depressed or inhibited feeding activity in all sponges tested. While performed under laboratory conditions on a limited number of specimens, this work highlights the possible sensitivity of deep-sea demosponges to various types and levels of biotic and abiotic factors, inferring a consequent vulnerability to natural and anthropogenic disturbances.

  7. Unraveling aspects of Bacillus amyloliquefaciens mediated enhanced production of rice under biotic stress of Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Suchi eSrivastava

    2016-05-01

    Full Text Available Rhizoctonia solani (RS is a necrotrophic fungi causing sheath blight in rice leading to substantial loss in yield. Excessive and persistent use of preventive chemicals raises human health and environment safety concerns. As an alternative, use of biocontrol agents is highly recommended. In the present study an abiotic stress tolerant, plant growth promoting rhizobacteria Bacillus amyloliquefaciens (SN13 is demonstrated to act as a biocontrol agent and enhance immune response against RS in rice by modulating various physiological, metabolic and molecular functions. A sustained tolerance by SN13 primed plant over a longer period of time, post RS infection may be attributed to several unconventional aspects of the plants’ physiological status. The prolonged stress tolerance observed in presence of SN13 is characterized by (a involvement of bacterial mycolytic enzymes, (b sustained maintenance of elicitors to keep the immune system induced involving non-metabolizable sugars such as turanose besides the known elicitors, (c a delicate balance of ROS and ROS scavengers through production of proline, mannitol and arabitol and rare sugars like fructopyranose, β-d glucopyranose and myoinositol and expression of ferric reductases and hypoxia induced proteins, (d production of metabolites like quinozoline and expression of terpene synthase and (e hormonal cross talk. As the novel aspect of biological control this study highlights the role of rare sugars, maintenance of hypoxic conditions, and sucrose and starch metabolism in Bacillus amyloliquifaciens (SN13 mediated sustained biotic stress tolerance in rice.

  8. Ecogeographical Variation in Skull Shape of South-American Canids: Abiotic or Biotic Processes?

    Science.gov (United States)

    de Moura Bubadué, Jamile; Cáceres, Nilton; Dos Santos Carvalho, Renan; Meloro, Carlo

    Species morphological changes can be mutually influenced by environmental or biotic factors, such as competition. South American canids represent a quite recent radiation of taxa that evolved forms very disparate in phenotype, ecology and behaviour. Today, in the central part of South America there is one dominant large species (the maned wolf, Chrysocyon brachyurus ) that directly influence sympatric smaller taxa via interspecific killing. Further south, three species of similar sized foxes ( Lycalopex spp.) share the same habitats. Such unique combination of taxa and geographic distribution makes South American dogs an ideal group to test for the simultaneous impact of climate and competition on phenotypic variation. Using geometric morphometrics, we quantified skull size and shape of 431 specimens belonging to the eight extant South American canid species: Atelocynus microtis , Cerdocyon thous , Ch. brachyurus , Lycalopex culpaeus , L. griseus , L. gymnocercus , L. vetulus and Speothos venaticus . South American canids are significantly different in both skull size and shape. The hypercarnivorous bush dog is mostly distinct in shape from all the other taxa while a degree of overlap in shape-but not size-occurs between species of the genus Lycalopex . Both climate and competition impacts interspecific morphological variation. We identified climatic adaptations as the main driving force of diversification for the South American canids. Competition has a lower degree of impact on their skull morphology although it might have played a role in the past, when canid community was richer in morphotypes.

  9. Biotic and abiotic retention, recycling and remineralization of metals in the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Philip W.; Ellwood, Michael J.; Tagliabue, Alessandro; Twining , Benjamin S. (ANU); (Liverpool); (Tasmania); (Bigelow)

    2017-03-01

    Trace metals shape both the biogeochemical functioning and biological structure of oceanic provinces. Trace metal biogeochemistry has primarily focused on modes of external supply of metals from aeolian, hydrothermal, sedimentary and other sources. However, metals also undergo internal transformations such as abiotic and biotic retention, recycling and remineralization. The role of these internal transformations in metal biogeochemical cycling is now coming into focus. First, the retention of metals by biota in the surface ocean for days, weeks or months depends on taxon-specific metal requirements of phytoplankton, and on their ultimate fate: that is, viral lysis, senescence, grazing and/or export to depth. Rapid recycling of metals in the surface ocean can extend seasonal productivity by maintaining higher levels of metal bioavailability compared to the influence of external metal input alone. As metal-containing organic particles are exported from the surface ocean, different metals exhibit distinct patterns of remineralization with depth. These patterns are mediated by a wide range of physicochemical and microbial processes such as the ability of particles to sorb metals, and are influenced by the mineral and organic characteristics of sinking particles. We conclude that internal metal transformations play an essential role in controlling metal bioavailability, phytoplankton distributions and the subsurface resupply of metals.

  10. Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2015-06-01

    Full Text Available A Lake Multi-biotic Integrity Index (LMII for the China’s second largest interior lake (Dongting Lake was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P<0.001. The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.

  11. Identifying Watershed, Landscape, and Engineering Design Factors that Influence the Biotic Condition of Restored Streams

    Directory of Open Access Journals (Sweden)

    Barbara Doll

    2016-04-01

    Full Text Available Restored stream reaches at 79 sites across North Carolina were sampled for aquatic macroinvertebrates using a rapid bioassessment protocol. Morphological design parameters and geographic factors, including watershed and landscape parameters (e.g., valley slope, substrate, were also compiled for these streams. Principal component regression analyses revealed correlations between design and landscape variables with macroinvertebrate metrics. The correlations were strengthened by adding watershed variables. Ridge regression was used to find the best-fit model for predicting dominant taxa from the “pollution sensitive” orders of Ephemeroptera (mayflies, Plecoptera (stoneflies, and Trichoptera (caddisflies, or EPT taxa, resulting in coefficient weights that were most interpretable relative to site selection and design parameters. Results indicate that larger (wider streams located in the mountains and foothills where there are steeper valleys, larger substrate, and undeveloped watersheds are expected to have higher numbers of dominant EPT taxa. In addition, EPT taxa numbers are positively correlated with accessible floodplain width and negatively correlated with width-to-depth ratio and sinuosity. This study indicates that both site selection and design should be carefully considered in order to maximize the resulting biotic condition and associated potential ecological uplift of the stream.

  12. Monitoring airborne biotic contaminants in the indoor environment of pig and poultry confinement buildings.

    Science.gov (United States)

    Hong, Pei-Ying; Li, Xiangzhen; Yang, Xufei; Shinkai, Takumi; Zhang, Yuanhui; Wang, Xinlei; Mackie, Roderick I

    2012-06-01

    Given the growing concerns over human and animal health issues related to confined animal feeding operations, an in-depth examination is required to monitor for airborne bacteria and associated antibiotic resistance genes. Our 16S rRNA-based pyrosequencing revealed that the airborne microbial community skewed towards a higher abundance of Firmicutes (> 59.2%) and Bacteroidetes (4.2-31.4%) within the confinement buildings, while the office environment was predominated by Proteobacteria (55.2%). Furthermore, bioaerosols in the confinement buildings were sporadically associated with genera of potential pathogens, and these genera were more frequently observed in the bioaerosols of pig and layer hen confinement than the turkey confinement buildings and office environment. High abundances of tetracycline resistance genes (9.55 × 10(2) to 1.69 × 10(6) copies ng(-1) DNA) were also detected in the bioaerosols sampled from confinement buildings. Bacterial lineages present in the poultry bioaerosols clustered apart from those present in the pig bioaerosols and among the different phases of pig production, suggesting that different livestock as well as production phase were associated with a distinct airborne microbial community. By understanding the diversity of biotic contaminants associated with the different confinement buildings, this study facilitates the implementation of better management strategies to minimize potential health impacts on both livestock and humans working in this environment. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Topical report on reference eastern humid low-level sites

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

    1983-01-01

    The purpose of the work reported here was to develop an order-of-magnitude estimate for the potential dose to man resulting from biotic transport mechanisms at a humid reference low-level waste site in the eastern US. A description of the reference site is presented that includes the waste inventories, site characteristics and biological communites. Parameter values for biotic transport processes are based on data reported in current literature. Transport and exposure scenarios are developed for assessing biotic transport during 500 years following site closure. Calculations of radionuclide decay and waste container decomposition are made to estimate the quantities available for biotic transport. Doses to man are calculated for the biological transport of radionucludes at the reference site after loss of institutional control. These dose estimates are compared to dose estimates we calculated for the intruder-agricultural scenarios reported in the DEIS for 10 CFR 61 (NRC). Dose to man estimates as a result of cumulative biotic transport are calculated to be of the same order-of-magnitude as the dose resulting from the more commonly evaluated human intrusion scenario. The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by findings presented in this report. Through biotic transport, radionuclides can be moved to locations where they can enter exposure pathways to man

  14. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. A report on Tasks 1 and 2 of Phase I

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Cushing, C.E. Jr.; Harty, R.; Kennedy, W.E. Jr.; Simmons, M.A.; Soldat, J.K.; Swartzman, B.

    1982-07-01

    The purpose of the work reported here was to evaluate the relevance of biotic transport to the assessment of impacts and licensing of low-level waste disposal sites. Available computer models and their recent applications at low-level waste disposal sites are considered. Biotic transport mechanisms and processes for both terrestrial and aquatic systems are presented with examples from existing waste disposal sites. Following a proposed system for ranking radionuclides by their potential for biotic transport, recommendations for completing Phase I research are presented. To evaluate the long-term importance of biotic transport at low-level waste sites, scenarios for biotic pathways and mechanisms need to be developed. Scenarios should begin with a description of the waste form and should include a description of biotic processes and mechanisms, approximations of the magnitude of materials transported, and a linkage to processes or mechanisms in existing models. Once these scenarios are in place, existing models could be used to evaluate impacts resulting from biotic transport and to assess the relevance to site selection and licensing of low-level waste disposal sites

  15. Nurse plants, tree saplings and grazing pressure: changes in facilitation along a biotic environmental gradient

    NARCIS (Netherlands)

    Smit, C.; Vandenberghe, C.; Ouden, den J.; Muller-Scharer, H.

    2007-01-01

    Current conceptual models predict that an increase in stress shifts interactions between plants from competitive to facilitative; hence, facilitation is expected to gain in ecological importance with increasing stress. Little is known about how facilitative interactions between plants change with

  16. Nurse plants, tree saplings and grazing pressure : Changes in facilitation along a biotic environmental gradient

    NARCIS (Netherlands)

    Smit, Christian; Vandenberghe, Charlotte; den Ouden, Jan; Mueller-Schaerer, Heinz

    Current conceptual models predict that an increase in stress shifts interactions between plants from competitive to facilitative; hence, facilitation is expected to gain in ecological importance with increasing stress. Little is known about how facilitative interactions between plants change with

  17. Biotic and abiotic stress tolerance in transgenic tomatoes by constitutive expression of S-adenosylmethionine decarboxylase gene.

    Science.gov (United States)

    Hazarika, Pranjal; Rajam, Manchikatla Venkat

    2011-04-01

    Recent findings have implicated the role of polyamines (putrescine, spermidine and spermine) in stress tolerance. Therefore, the present work was carried out with the goal of generating transgenic tomato plants with human S-adenosylmethionine decarboxylase (samdc) gene, a key gene involved in biosynthesis of polyamines, viz. spermidine and spermine and evaluating the transgenic plants for tolerance to both biotic and abiotic stresses. Several putative transgenic tomato plants with normal phenotype were obtained, and the transgene integration and expression was validated by PCR, Southern blot analysis and RT-PCR analysis, respectively. The transgenic plants exhibited high levels of polyamines as compared to the untransformed control plants. They also showed increased resistance against two important fungal pathogens of tomato, the wilt causing Fusarium oxysporum and the early blight causing Alternaria solani and tolerance to multiple abiotic stresses such as salinity, drought, cold and high temperature. These results suggest that engineering polyamine accumulation can confer tolerance to both biotic and abiotic stresses in plants.

  18. Life’s Critical Role in the Long-term Carbon Cycle: the Biotic Enhancement of Weathering

    Directory of Open Access Journals (Sweden)

    David W. Schwartzman

    2017-06-01

    Full Text Available The biotic enhancement of weathering (BEW has important implications for the long-term carbon cycle, in particular as a driver of climatic cooling. The BEW factor is defined as how much faster the silicate weathering carbon sink is under biotic conditions than under abiotic conditions at the same atmospheric pCO2 level and surface temperature. The BEW factor and its evolution over geological time can potentially be inferred from consideration of empirical and theoretical weathering studies. Estimates of the global magnitude of the BEW are presented, drawing from laboratory, field, watershed data and models of the long-term carbon cycle, with values ranging from one to two orders of magnitude.

  19. Effects of Abiotic and Biotic Stresses on the Internalization and Dissemination of Human Norovirus Surrogates in Growing Romaine Lettuce.

    Science.gov (United States)

    DiCaprio, Erin; Purgianto, Anastasia; Li, Jianrong

    2015-07-01

    Human norovirus (NoV) is the major causative agent of fresh-produce-related outbreaks of gastroenteritis; however, the ecology and persistence of human NoV in produce systems are poorly understood. In this study, the effects of abiotic and biotic stresses on the internalization and dissemination of two human NoV surrogates (murine norovirus 1 [MNV-1] and Tulane virus [TV]) in romaine lettuce were determined. To induce abiotic stress, romaine lettuce was grown under drought and flood conditions that mimic extreme weather events, followed by inoculation of soil with MNV-1 or TV. Independently, lettuce plants were infected with lettuce mosaic virus (LMV) to induce biotic stress, followed by inoculation with TV. Plants were grown for 14 days, and viral titers in harvested tissues were determined by plaque assays. It was found that drought stress significantly decreased the rates of both MNV-1 and TV internalization and dissemination. In contrast, neither flood stress nor biotic stress significantly impacted viral internalization or dissemination. Additionally, the rates of TV internalization and dissemination in soil-grown lettuce were significantly higher than those for MNV-1. Collectively, these results demonstrated that (i) human NoV surrogates can be internalized via roots and disseminated to shoots and leaves of romaine lettuce grown in soil, (ii) abiotic stress (drought) but not biotic stress (LMV infection) affects the rates of viral internalization and dissemination, and (iii) the type of virus affects the efficiency of internalization and dissemination. This study also highlights the need to develop effective measures to eliminate internalized viruses in fresh produce. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. The benefits of biotics in erosion control materials for critical sites : better business, improved soil and stronger vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Myrowich, M.; Nelson, R. [Verdyol Plant Research, Riverton, MB (Canada)

    2010-07-01

    This paper discussed the advantages of biotics in erosion control materials, such as the inclusion of hydraulic growth mediums (HGMs) and beneficial growth stimulants, for critical sites. Biotics provide organic additives, and the growth mediums stimulate natural microbial activity, soil aggregate formation, and other natural topsoil forming processes to ensure the long-term health of vegetation. HGMs provide a living base for plants to grow without having to overhaul the entire topsoil structure. The two main components are the biotic system for improving soil and promoting vegetation and a tackifier to secure the HGM to the soil, enhance soil formation processes, and allow vegetation to get established. HGMs are suitable for mining and industrial reclamation because they improve soils and are more cost effective and environmentally sound than trucking in new soil to a site. Two case studies showed how vegetation is quickly established for long-term protection and the benefits for businesses using these erosion-control techniques. The second case study described the manner in which Hydro Quebec successfully employed HGMs to reclaim sensitive roadsides that were being built at construction sites near James Bay. HGMs were found to offer the right solution to the specifics of the site, such as highly erodible subsoil, no available topsoil, and an extremely short growing season. It was concluded that HGMs with biotic components and strong tackifiers improve the performance and economics of erosion control and the overall health of soils for the long-term sustainability of vegetative cover at sensitive sites. 7 refs., 2 figs.

  1. Predator-prey interactions as macro-scale drivers of species diversity in mammals

    DEFF Research Database (Denmark)

    Sandom, Christopher James; Sandel, Brody Steven; Dalby, Lars

    Background/Question/Methods Understanding the importance of predator-prey interactions for species diversity is a central theme in ecology, with fundamental consequences for predicting the responses of ecosystems to land use and climate change. We assessed the relative support for different...... mechanistic drivers of mammal species richness at macro-scales for two trophic levels: predators and prey. To disentangle biotic (i.e. functional predator-prey interactions) from abiotic (i.e. environmental) and bottom-up from top-down determinants we considered three hypotheses: 1) environmental factors...... that determine ecosystem productivity drive prey and predator richness (the productivity hypothesis, abiotic, bottom-up), 2) consumer richness is driven by resource diversity (the resource diversity hypothesis, biotic, bottom-up) and 3) consumers drive richness of their prey (the top-down hypothesis, biotic, top...

  2. Relative Importance of Biotic and Abiotic Forces on the Composition and Dynamics of a Soft-Sediment Intertidal Community

    Science.gov (United States)

    Barbeau, Myriam A.

    2016-01-01

    Top-down, bottom-up, middle-out and abiotic factors are usually viewed as main forces structuring biological communities, although assessment of their relative importance, in a single study, is rarely done. We quantified, using multivariate methods, associations between abiotic and biotic (top-down, bottom-up and middle-out) variables and infaunal population/community variation on intertidal mudflats in the Bay of Fundy, Canada, over two years. Our analysis indicated that spatial structural factors like site and plot accounted for most of the community and population variation. Although we observed a significant relationship between the community/populations and the biotic and abiotic variables, most were of minor importance relative to the structural factors. We suggest that community and population structure were relatively uncoupled from the structuring influences of biotic and abiotic factors in this system because of high concentrations of resources that sustain high densities of infauna and limit exploitative competition. Furthermore, we hypothesize that the infaunal community primarily reflects stochastic spatial events, namely a “first come, first served” process. PMID:26790098

  3. Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

    Directory of Open Access Journals (Sweden)

    Reza Mohammadi

    2015-10-01

    Full Text Available Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat (Triticum turgidum L. var. durum entries originating in several countries along with four check varieties were evaluated for biotic stresses: yellow rust (Puccinia striiformis Westendorf f. sp. tritici and wheat stem sawfly (WSS Cephus cinctus Norton (Hymenoptera: Cephidae, and abiotic stresses: cold and drought. The main objectives were to (i quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and (ii characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed. Landraces resistant to each stress were identified and agronomically characterized. Percentage reduction due to the stresses varied from 11.4% (yellow rust to 21.6% (cold stress for 1000-kernel weight (TKW and from 19.9 (yellow rust to 91.9% (cold stress for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

  4. MANAGEMENT OF THE WHITE-CLAWED CRAYFISH (AUSTROPOTAMOBIUS PALLIPES IN WESTERN FRANCE: ABIOTIC AND BIOTIC FACTORS STUDY

    Directory of Open Access Journals (Sweden)

    TROUILHE M. C.

    2003-04-01

    Full Text Available In France, the distribution of the white-clawed crayfish, Austropotamobius pallipes (Lereboullet, 1858, is restricted, fragmented and mainly located in headwaters. To preserve this indigenous species, it is necessary to characterize its ecological requirements (water and habitat quality. With this aim in view, a two-year study is being conducted in the Deux-Sèvres department (Western France since November 2002. Nine brooks from four different catchments are monitored regularly; eight of the nine brooks harbour whiteclawed crayfish populations. Two sampling sites are surveyed per brook, the first being where the crayfish population is located and the second 2 to 3 km downstream. Physicochemical parameters (18 are measured twice monthly and biotic factors are estimated twice yearly. In this study, the I.B.G.N. (Indice Biologique Global Normalisé protocol based on the determination of macroinvertebrates was used as a biotic index of biological water quality. Results of this preliminary study on two brooks (Thouet and Verdonnière show that physico-chemical and biological data considered separately do not provide reliable information about A. pallipes ecological requirements. However, the use of multivariate analyses (Principal Component Analysis to combine abiotic and biotic factors highlights a good correlation between these parameters. Organic matter appears to be a better discriminating factor than mineral matter affecting presence or absence of the whiteclawed crayfish.

  5. An Index of Biotic Integrity for shallow streams of the Hondo River basin, Yucatan Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Schmitter-Soto, Juan J., E-mail: jschmitt@ecosur.mx; Ruiz-Cauich, Lissie E.; Herrera, Roberto L.; Gonzalez-Solis, David

    2011-01-15

    An Index of Biotic Integrity (IBI) is proposed, based on the fish communities and populations in streams of the Hondo River basin, Mexico-Belize. Freshwater environments in this area are threatened by exotic fishes, eutrophication, and pesticide pollution, among other problems. This IBI should allow to identify the most vulnerable sites and eventually guide rehabilitation efforts. Data on composition, structure, and function of fish communities were evaluated. Twenty-three sites in the Mexican part of the basin were explored; a stratified sample of 13 sites was used to design the IBI, and the rest were used to test and refine the index. Thirty-four candidate indicator metrics were scanned for their correlation with an index of water and habitat quality (IWHQ), as well as for the possible influence of stream width and altitude or distance to the Hondo River mainstem. Twelve variables were selected to constitute the IBI: relative abundances of Astyanax aeneus, 'Cichlasoma' urophthalmus, Poecilia mexicana, Poecilia sp. (a new species, probably endemic to the upper Hondo River basin), Xiphophorus hellerii, and X. maculatus; relative abundances of bentholimnetic, herbivore, and sensitive species; percentage of native and tolerant species; and Pielou's evenness index. Most of the sites have a low-medium quality and integrity, showing impact due to partial channelization or to suboptimal water quality, reflected in scarcity or absence of sensitive species, frequent excess of tolerant species, occasional presence of exotics, dominance of herbivores (perhaps due to proliferation of filamentous algae), or dominance of the opportunistic species P. mexicana. The streams with better water and habitat quality are those farthest away from the river mainstem, probably because of lower human population and economical production. - Research Highlights: {yields} An Index of Biotic Integrity based on fishes is proposed for streams of the Hondo River basin. {yields

  6. Using thermodynamics to assess biotic and abiotic impediments to root water uptake

    Science.gov (United States)

    Bechmann, Marcel; Hildebrandt, Anke; Kleidon, Axel

    2016-04-01

    Root water uptake has been the subject of extensive research, dealing with understanding the processes limiting transpiration and understanding strategies of plants to avoid water stress. Many of those studies use models of water flow from the soil through the plant into the atmosphere to learn about biotic and abiotic factors affecting plant water relations. One important question in this context is to identify those processes that are most limiting to water transport, and specifically whether these processes lie within the plant or the soil? Here, we propose to use a thermodynamic formulation of root water uptake to answer this question. The method allows us to separate the energy exported at the root collar into a sum of energy fluxes related to all processes along the flow path, notably including the effect of increasing water retention in drier soils. Evaluation of the several contributions allows us to identify and rank the processes by how much these impede water flow from the soil to the atmosphere. The application of this approach to a complex 3-dimensional root water uptake model reveals insights on the role of root versus soil resistances to limit water flow. We investigate the efficiency of root water uptake in an ensemble of root systems with varying root hydraulic properties. While root morphology is kept the same, root radial and axial resistances are artificially varied. Starting with entirely young systems (uptake roots, high radial, low axial conductance) we increasingly add older roots (transport roots, high axial, low radial conductance) to improve transport within root systems. This yields a range of root hydraulic architectures, where the extremes are limited either by radial uptake capacity or low capacity to transport water along the root system. We model root water uptake in this range of root systems with a 3-dimensional root water uptake model in two different soils, applying constant flux boundary conditions in a dry down experiment and

  7. Dynamic species classification of microorganisms across time, abiotic and biotic environments-A sliding window approach.

    Directory of Open Access Journals (Sweden)

    Frank Pennekamp

    Full Text Available The development of video-based monitoring methods allows for rapid, dynamic and accurate monitoring of individuals or communities, compared to slower traditional methods, with far reaching ecological and evolutionary applications. Large amounts of data are generated using video-based methods, which can be effectively processed using machine learning (ML algorithms into meaningful ecological information. ML uses user defined classes (e.g. species, derived from a subset (i.e. training data of video-observed quantitative features (e.g. phenotypic variation, to infer classes in subsequent observations. However, phenotypic variation often changes due to environmental conditions, which may lead to poor classification, if environmentally induced variation in phenotypes is not accounted for. Here we describe a framework for classifying species under changing environmental conditions based on the random forest classification. A sliding window approach was developed that restricts temporal and environmentally conditions to improve the classification. We tested our approach by applying the classification framework to experimental data. The experiment used a set of six ciliate species to monitor changes in community structure and behavior over hundreds of generations, in dozens of species combinations and across a temperature gradient. Differences in biotic and abiotic conditions caused simplistic classification approaches to be unsuccessful. In contrast, the sliding window approach allowed classification to be highly successful, as phenotypic differences driven by environmental change, could be captured by the classifier. Importantly, classification using the random forest algorithm showed comparable success when validated against traditional, slower, manual identification. Our framework allows for reliable classification in dynamic environments, and may help to improve strategies for long-term monitoring of species in changing environments. Our

  8. Dynamic species classification of microorganisms across time, abiotic and biotic environments-A sliding window approach.

    Science.gov (United States)

    Pennekamp, Frank; Griffiths, Jason I; Fronhofer, Emanuel A; Garnier, Aurélie; Seymour, Mathew; Altermatt, Florian; Petchey, Owen L

    2017-01-01

    The development of video-based monitoring methods allows for rapid, dynamic and accurate monitoring of individuals or communities, compared to slower traditional methods, with far reaching ecological and evolutionary applications. Large amounts of data are generated using video-based methods, which can be effectively processed using machine learning (ML) algorithms into meaningful ecological information. ML uses user defined classes (e.g. species), derived from a subset (i.e. training data) of video-observed quantitative features (e.g. phenotypic variation), to infer classes in subsequent observations. However, phenotypic variation often changes due to environmental conditions, which may lead to poor classification, if environmentally induced variation in phenotypes is not accounted for. Here we describe a framework for classifying species under changing environmental conditions based on the random forest classification. A sliding window approach was developed that restricts temporal and environmentally conditions to improve the classification. We tested our approach by applying the classification framework to experimental data. The experiment used a set of six ciliate species to monitor changes in community structure and behavior over hundreds of generations, in dozens of species combinations and across a temperature gradient. Differences in biotic and abiotic conditions caused simplistic classification approaches to be unsuccessful. In contrast, the sliding window approach allowed classification to be highly successful, as phenotypic differences driven by environmental change, could be captured by the classifier. Importantly, classification using the random forest algorithm showed comparable success when validated against traditional, slower, manual identification. Our framework allows for reliable classification in dynamic environments, and may help to improve strategies for long-term monitoring of species in changing environments. Our classification pipeline

  9. Abiotic and biotic controls of cryptobenthic fish assemblages across a Caribbean seascape

    Science.gov (United States)

    Harborne, A. R.; Jelks, H. L.; Smith-Vaniz, W. F.; Rocha, L. A.

    2012-12-01

    The majority of fish studies on coral reefs consider only non-cryptic species and, despite their functional importance, data on cryptic species are scarce. This study investigates inter-habitat variation in Caribbean cryptobenthic fishes by re-analysing a comprehensive data set from 58 rotenone stations around Buck Island, U.S. Virgin Islands. Boosted regression trees were used to associate the density and diversity of non-piscivorous cryptobenthic fishes, both in the entire data set and on reef habitats alone, with 14 abiotic and biotic variables. The study also models the habitat requirements of the three commonest species. Dead coral cover was the first or second most important variable in six of the eight models constructed. For example, within the entire data set, the number of species and total fish density increased approximately linearly with increasing dead coral cover. Dead coral was also important in multivariate analyses that discriminated 10 assemblages within the entire data set. On reef habitats, the number of species and total fish density increased dramatically when dead coral exceeded ~55 %. Live coral cover was typically less important for explaining variance in fish assemblages than dead coral, but live corals were important for maintaining high fish diversity. Coral species favoured by cryptobenthic species may be particularly susceptible to mortality, but dead coral may also provide abundant food and shelter for many fishes. Piscivore density was a key variable in the final models, but typically increased with increasing cryptobenthic fish diversity and abundance, suggesting both groups of fishes are responding to the same habitat variables. The density of territorial damselfishes reduced the number of cryptobenthic fish species on reef habitats. Finally, habitats delineated by standard remote sensing techniques supported distinct cryptobenthic fish assemblages, suggesting that such maps can be used as surrogates of general patterns of cryptic

  10. A comparison of survey methods to evaluate macrophyte index of biotic integrity performance in Minnesota lakes

    Science.gov (United States)

    Vondracek, Bruce C.; Koch, Justine D.; Beck, Marcus W.

    2014-01-01

    Aquatic macrophytes shape trophic web dynamics, provide food and refuge for macroinvertebrates and fish, and increase nutrient retention, sediment stabilization, and water clarity. Macrophytes are well-suited as indicators of ecological health because they are immobile, relatively easy to sample and identify, and respond to anthropogenic disturbance on an ecological time scale. Aquatic plant monitoring programs can provide valuable information to water resource managers, especially in conjunction with macrophyte-based indices of biotic integrity (IBI). However, there are several current sampling designs and the precision of IBI scores has not been evaluated across different surveys. We evaluated the performance of the Minnesota macrophyte-based IBI for two survey designs; a point intercept (PI) survey and a belt transect (BT) survey. PI surveys are time intensive, especially on large lakes, whereas BT are less time intensive and have been used historically in Minnesota. Our objectives were to compare the PI surveys with BT surveys on the same lakes, and to modify the BT survey (MT survey) to improve information obtained from BT surveys. BT surveys consistently overestimated IBI scores compared to the PI method (t = 6.268, df = 60, p < 0.001). Overall IBI scores calculated from MT surveys differed significantly from PI scores, but on average, MT surveys predicted scores only 3% lower than PI scores. Implementation of the Minnesota macrophyte-based IBI through the adoption of the MT survey approach would improve sampling efficiency and enable widespread documentation of the effects of landscape change, shifts in hydrologic regimes, and other anthropogenic activities on the integrity of lacustrine systems.

  11. Aerobic bacterial flora of biotic and abiotic compartments of a hyperendemic Zoonotic Cutaneous Leishmaniasis (ZCL) focus.

    Science.gov (United States)

    Maleki-Ravasan, Naseh; Oshaghi, Mohammad Ali; Afshar, Davoud; Arandian, Mohammad Hossein; Hajikhani, Sara; Akhavan, Amir Ahmad; Yakhchali, Bagher; Shirazi, Mohammad Hasan; Rassi, Yavar; Jafari, Reza; Aminian, Koorosh; Fazeli-Varzaneh, Reza Ali; Durvasula, Ravi

    2015-01-29

    Identification of the microflora of the sand fly gut and the environmental distribution of these bacteria are important components for paratransgenic control of Leishmania transmission by sand flies. Biotic and abiotic bacterial communities of four compartments of a hyper-endemic focus of Zoonotic Cutaneous Leishmaniasis (ZCL) were investigated using 16S ribosomal DNA sequencing and phylogenetic tree construction. These compartments include Phlebotomus papatasi's gut, skin and intestinal tract of great gerbil Rhombomys opimus, the gerbil nest supplies, and plant food sources of the vectors and reservoirs. Sequence homology analysis using nine available 16S rDNA data bases revealed 40, 24, 15 and 14 aerobic bacterial species from the vector guts, the gerbil bodies, the gerbil nests, and the plants, respectively. The isolated bacteria belong to wide ranges including aerobic to facultative anaerobic, pathogen to commensals, sand fly oviposition inducers, land to air and ocean habitats, animal and human probiotics, and plant growth-promoting rhizobacteria. Matching data analysis suggested that the adult P. papatasi gut bacteria could be acquired from three routes, adult sugar feeding on the plant saps, adult blood feeding on the animal host, and larval feeding from nest supplies. However, our laboratory experiment showed that none of the bacteria of the reservoir skin was transmitted to female sand fly guts via blood feeding. The microflora of sand fly guts were associated with the sand fly environment in which the predominant bacteria were Microbacterium, Pseudomonas, and Staphylococcus in human dwellings, cattle farms, and rodent colonies, respectively. Staphylococcus aureus was the most common bacterium in sand fly guts. Presence of some sand fly ovipoisition inducers such Bacillus spp. and Staphylococcus saprophyticus support association between gut flora and oviposition induction. Results of this study showed that Bacillus subtilis and Enterobacter cloacae

  12. Biotic and abiotic factors influencing zooplankton vertical distribution in Lake Huron

    Science.gov (United States)

    Nowicki, Carly J.; Bunnell, David B.; Armenio, Patricia M.; Warner, David M.; Vanderploeg, Henry A.; Cavaletto, Joann F.; Mayer, Christine M.; Adams, Jean V.

    2017-01-01

    The vertical distribution of zooplankton can have substantial influence on trophic structure in freshwater systems, particularly by determining spatial overlap for predator/prey dynamics and influencing energy transfer. The zooplankton community in some of the Laurentian Great Lakes has undergone changes in composition and declines in total biomass, especially after 2003. Mechanisms underlying these zooplankton changes remain poorly understood, in part, because few studies have described their vertical distributions during daytime and nighttime conditions or evaluated the extent to which predation, resources, or environmental conditions could explain their distribution patterns. Within multiple 24-h periods during July through October 2012 in Lake Huron, we conducted daytime and nighttime sampling of zooplankton, and measured food (chlorophyll-a), temperature, light (Secchi disk depth), and planktivory (biomass of Bythotrephes longimanus and Mysis diluviana). We used linear mixed models to determine whether the densities for 22 zooplankton taxa varied between day and night in the epi-, meta-, and hypolimnion. For eight taxa, higher epilimnetic densities were observed at night than during the day; general linear models revealed these patterns were best explained by Mysis diluviana (four taxa), Secchi disk depth (three taxa), epilimnetic water temperature (three taxa), chlorophyll (one taxon), and biomass of Bythotrephes longimanus (one taxon). By investigating the potential effects of both biotic and abiotic variables on the vertical distribution of crustacean zooplankton and rotifers, we provide descriptions of the Lake Huron zooplankton community and discuss how future changes in food web dynamics or climate change may alter zooplankton distribution in freshwater environments.

  13. Abiotic and biotic determinants of leaf carbon exchange capacity from tropical to high boreal biomes

    Science.gov (United States)

    Smith, N. G.; Dukes, J. S.

    2016-12-01

    Photosynthesis and respiration on land represent the two largest fluxes of carbon dioxide between the atmosphere and the Earth's surface. As such, the Earth System Models that are used to project climate change are high sensitive to these processes. Studies have found that much of this uncertainty is due to the formulation and parameterization of plant photosynthetic and respiratory capacity. Here, we quantified the abiotic and biotic factors that determine photosynthetic and respiratory capacity at large spatial scales. Specifically, we measured the maximum rate of Rubisco carboxylation (Vcmax), the maximum rate of Ribulose-1,5-bisphosphate regeneration (Jmax), and leaf dark respiration (Rd) in >600 individuals of 98 plant species from the tropical to high boreal biomes of Northern and Central America. We also measured a bevy of covariates including plant functional type, leaf nitrogen content, short- and long-term climate, leaf water potential, plant size, and leaf mass per area. We found that plant functional type and leaf nitrogen content were the primary determinants of Vcmax, Jmax, and Rd. Mean annual temperature and mean annual precipitation were not significant predictors of these rates. However, short-term climatic variables, specifically soil moisture and air temperature over the previous 25 days, were significant predictors and indicated that heat and soil moisture deficits combine to reduce photosynthetic capacity and increase respiratory capacity. Finally, these data were used as a model benchmarking tool for the Community Land Model version 4.5 (CLM 4.5). The benchmarking analyses determined errors in the leaf nitrogen allocation scheme of CLM 4.5. Under high leaf nitrogen levels within a plant type the model overestimated Vcmax and Jmax. This result suggested that plants were altering their nitrogen allocation patterns when leaf nitrogen levels were high, an effect that was not being captured by the model. These data, taken with models in mind

  14. Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress.

    Science.gov (United States)

    Kwon, Kwang-Chul; Verma, Dheeraj; Jin, Shuangxia; Singh, Nameirakpam D; Daniell, Henry

    2013-01-01

    Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress) or paraquat (abiotic stress), GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II) made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide), which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These results suggest a

  15. Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress.

    Directory of Open Access Journals (Sweden)

    Kwang-Chul Kwon

    Full Text Available Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress or paraquat (abiotic stress, GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide, which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These

  16. 1983 biotic studies of Yucca Mountain, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    O'Farrell, T.P.; Collins, E.

    1984-04-01

    A 27.5-square-mile portion of Yucca Mountain on and adjacent to the US Department of Energy's Nevada Test Site, Nye County, Nevada, is being considered as a potential location for a national high-level radioactive waste repository. Preliminary geologic and environmental characterization studies have been supported and more extensive studies are planned. Goals of the biotic surveys were to identify species of concern, describe major floral and faunal associations, and assess possible impacts of characterization and operational activities. Floral associations observed were characteristic of either the Mojave or Transition deserts that are widely distributed in southern Nevada. Diversity, in terms of total number of perennial species represented, was higher in Transition Desert associations than in Mojave Desert associations. Canopy coverage of associations fell within the range of reported values, but tended to be more homogeneous than expected. Annual vegetation was found to be diverse only where the frequency of Bromus rubens was low. Ground cover of winter annuals, especially annual grasses, was observed to be very dense in 1983. The threat of range fires on Yucca Mountain was high because of the increased amount of dead litter and the decreased amount of bare ground. Significant variability was observed in the distribution and relative abundance of several small mammal species between 1982 and 1983. Desert tortoise were found in low densities comparable with those observed in 1982. Evidence of recent activity, which included sighting of two live tortoises, was found in five areas on Yucca Mountain. Two of these areas have a high probability of sustaining significant impacts if a repository is constructed. Regeneration of aboveground shrub parts from root crowns was observed in areas damaged in 1982 by seismic testing with Vibroseis machines. These areas, which had been cleared to bare dirt by passage of the machines, also supported lush stands of winter annuals

  17. Release of Proteins from Intact Chloroplasts Induced by Reactive Oxygen Species during Biotic and Abiotic Stress

    Science.gov (United States)

    Singh, Nameirakpam D.; Daniell, Henry

    2013-01-01

    Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress) or paraquat (abiotic stress), GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II) made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide), which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These results suggest a

  18. SERDP ER-1421 Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; McKinley, James P.; Crocker, Fiona H.; Breshears, Andrew T.; Devary, Brooks J.; Fredrickson, Herbert L.; Thompson, Karen T.

    2009-09-30

    This laboratory-scale project was initiated to investigate in situ abiotic/biotic mineralization of NDMA. Under iron-reducing conditions, aquifer sediments showed rapid abiotic NDMA degradation to dimethylamine (DMA), nitrate, formate, and finally, CO2. These are the first reported experiments of abiotic NDMA mineralization. The NDMA reactivity of these different iron phases showed that adsorbed ferrous iron was the dominant reactive phase that promoted NDMA reduction, and other ferrous phases present (siderite, iron sulfide, magnetite, structural ferrous iron in 2:1 clays) did not promote NDMA degradation. In contrast, oxic sediments that were biostimulated with propane promoted biomineralization of NDMA by a cometabolic monooxygenase enzyme process. Other monooxygenase enzyme processes were not stimulated with methane or toluene additions, and acetylene addition did not block mineralization. Although NDMA mineralization extent was the highest in oxic, biostimulated sediments (30 to 82%, compared to 10 to 26% for abiotic mineralization in reduced sediments), large 1-D column studies (high sediment/water ratio of aquifers) showed 5.6 times higher NDMA mineralization rates in reduced sediment (half-life 410 ± 147 h) than oxic biomineralization (half life 2293 ± 1866 h). Sequential reduced/oxic biostimulated sediment mineralization (half-life 3180 ± 1094 h) was also inefficient compared to reduced sediment. These promising laboratory-scale results for NDMA mineralization should be investigated at field scale. Future studies of NDMA remediation should focus on the comparison of this in situ abiotic NDMA mineralization (iron-reducing environments) to ex situ biomineralization, which has been shown successful in other studies.

  19. Nonlinear disruption of ecological interactions in response to nitrogen deposition.

    Science.gov (United States)

    Ochoa-Hueso, Raúl

    2016-10-01

    Global environmental change (GEC) is affecting species interactions and causing a rapid decline in biodiversity. In this study, I present a new Ecosystem Disruption Index to quantify the impacts of simulated nitrogen (N) deposition (0, 10, 20, and 50 kg N·ha -1 ·yr -1  + 6-7 kg N·ha -1 ·yr -1 background) on abiotic and biotic ecological interactions. This comparative index is based on pairwise linear and quadratic regression matrices. These matrices, calculated at the N treatment level, were constructed using a range of abiotic and biotic ecosystem constituents: soil pH, shrub cover, and the first component of several separate principal component analyses using soil fertility data (total carbon and N) and community data (annual plants, microorganisms, biocrusts, edaphic fauna) for a total of seven ecosystem constituents. Four years of N fertilization in a semiarid shrubland completely disrupted the network of ecological interactions, with a greater proportional increase in ecosystem disruption at low N addition levels. Biotic interactions, particularly those involving microbes, shrubs, and edaphic fauna, were more prone to be lost in response to N, whereas interactions involving soil properties were more resilient. In contrast, edaphic fauna was the only group directly affected by N addition, with mites and collembolans increasing their abundance with up to 20 kg N·ha -1 ·yr -1 and then decreasing, which supports the idea of higher-trophic-level organisms being more sensitive to disturbance due to more complex links with other ecosystem constituents. Future experimental studies evaluating the impacts of N deposition, and possibly other GEC drivers, on biodiversity and biotic and abiotic interactions may be able to explain results more effectively in the context of ecological networks as a key feature of ecosystem sensitivity. © 2016 by the Ecological Society of America.

  20. Hydro-chemical study of the evolution of interstellar pre-biotic molecules during the collapse of molecular clouds

    International Nuclear Information System (INIS)

    Majumdar, Liton; Das, Ankan; Chakrabarti, Sandip K.; Chakrabarti, Sonali

    2012-01-01

    One of the stumbling blocks for studying the evolution of interstellar molecules is the lack of adequate knowledge about the rate coefficients of various reactions which take place in the interstellar medium and molecular clouds. Some theoretical models of rate coefficients do exist in the literature for computing abundances of complex pre-biotic molecules. So far these have been used to study the abundances of these molecules in space. However, in order to obtain more accurate final compositions in these media, we have calculated the rate coefficients for the formation of some of the most important interstellar pre-biotic molecules by using quantum chemical theory. We use these rates inside our hydro-chemical model to examine the chemical evolution and final abundances of pre-biotic species during the collapsing phase of a proto-star. We find that a significant amount of various pre-biotic molecules could be produced during the collapse phase of a proto-star. We thoroughly study the formation of these molecules via successive neutral-neutral and radical-radical/radical-molecular reactions. We present the time evolution of the chemical species with an emphasis on how the production of these molecules varies with the depth of a cloud. We compare the formation of adenine in interstellar space using our rate-coefficients and using those obtained from existing theoretical models. Formation routes of the pre-biotic molecules are found to be highly dependent on the abundances of the reactive species and the rate coefficients involved in the reactions. The presence of grains strongly affects the abundances of the gas phase species. We also carry out a comparative study between different pathways available for the synthesis of adenine, alanine, glycine and other molecules considered in our network. Despite the huge abundances of the neutral reactive species, production of adenine is found to be strongly dominated by the radical-radical/radical-molecular reaction pathways

  1. Large-scale biotic interaction effects - tree cover interacts with shade toler-ance to affect distribution patterns of herb and shrub species across the Alps

    DEFF Research Database (Denmark)

    Nieto-Lugilde, Diego; Lenoir, Jonathan; Abdulhak, Sylvain

    2012-01-01

    , we simulated a removal experiment by comparing the elevational distribution of each species under high and low tree cover. Tree cover improved model performances and species’ response curves to a tree cover gradient varied depending on their shade tolerance, supporting the hypothesized antagonistic...... distributions has scarcely been investigated. Here, we used species distribution modeling (SDM) to assess the effect of tree cover on the elevational range limits of 1,378 herb and shrub species across the Alps, based on 18,798 vegetation plots. We hypothesize that tree cover will have a negative effect...

  2. Biotic and environmental dynamics through the Late Jurassic-Early Cretaceous transition: evidence for protracted faunal and ecological turnover.

    Science.gov (United States)

    Tennant, Jonathan P; Mannion, Philip D; Upchurch, Paul; Sutton, Mark D; Price, Gregory D

    2017-05-01

    The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic-Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short-term catastrophic events, large-scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary 'event', which hints at a 'cascade model' of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more-specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium-sized tetanuran theropods declined, and were replaced by larger-bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non-archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low-latitude, shallow marine shelf-dwelling faunas

  3. Latest Paleocene lithologic and biotic events in neritic deposits of southwestern New Jersey

    Science.gov (United States)

    Gibson, Thomas G.; Bybell, Laurel M.; Owens, James P.

    1993-01-01

    In the southwestern New Jersey Coastal Plain, four drill holes contain continuous neritic sedimentation across the Paleocene/Eocene boundary (calcareous nannofossil Zone NP 9/NP 10 boundary). Significant lithologic and biotic changes occur in these strata near the top of the Paleocene. Global warming, increased precipitation, and other oceanographic and climatic events that have been recognized in high-latitude, deep-oceanic deposits of the latest Paleocene also influenced mid-latitude, shallow-marine, and terrestrial environments of the western North Atlantic. The diverse, well-preserved calcareous nannofossil flora that is present throughout the entire New Jersey boundary section accurately places these events within the uppermost part of the upper Paleocene Zone NP 9. Several rapid but gradational changes occur within a 1.1-m interval near the top of Zone NP 9. The changes include (1) a change in lithology from glauconitic quartz sand to clay, (2) a change in clay mineral suites from illite/smectite-dominated to kaolinite-dominated, (3) a change in benthic foraminiferal assemblages to a lower diversity fauna suggestive of low-oxygen environments, (4) a significant increase in planktonic foraminiferal abundance, and (5) an increased species turnover rate in marine calcareous nannofossils. Pollen was sparse in the New Jersey drill holes, but terrestrial sporomorph species in Virginia exhibit increased turnover rates at a correlative level. Foraminiferal assemblages and lithology indicate that relative sea level rose in New Jersey at the same time as these late Paleocene events occurred in late Biochron NP 9. The higher sea levels influenced sediment type and absolute abundance of planktonic foraminifers in the deposits. Above the initial increase of kaolinite in the upper part of Zone NP 9, the kaolinite percentage continues to increase, and the maximum kaolinite value occurs in the uppermost part of Zone NP 9. There are few changes in either the sediments or the

  4. Adaptation of the MapMan ontology to biotic stress responses: application in solanaceous species

    Directory of Open Access Journals (Sweden)

    Stitt Mark

    2007-09-01

    Full Text Available Abstract Background The results of transcriptome microarray analysis are usually presented as a list of differentially expressed genes. As these lists can be long, it is hard to interpret the desired experimental treatment effect on the physiology of analysed tissue, e.g. via selected metabolic or other pathways. For some organisms, gene ontologies and data visualization software have been implemented to overcome this problem, whereas for others, software adaptation is yet to be done. Results We present the classification of tentative potato contigs from the potato gene index (StGI available from Dana-Farber Cancer Institute (DFCI into the MapMan ontology to enable the application of the MapMan family of tools to potato microarrays. Special attention has been focused on mapping genes that could not be annotated based on similarity to Arabidopsis genes alone, thus possibly representing genes unique for potato. 97 such genes were classified into functional BINs (i.e. functional classes after manual annotation. A new pathway, focusing on biotic stress responses, has been added and can be used for all other organisms for which mappings have been done. The BIN representation on the potato 10 k cDNA microarray, in comparison with all putative potato gene sequences, has been tested. The functionality of the prepared potato mapping was validated with experimental data on plant response to viral infection. In total 43,408 unigenes were mapped into 35 corresponding BINs. Conclusion The potato mappings can be used to visualize up-to-date, publicly available, expressed sequence tags (ESTs and other sequences from GenBank, in combination with metabolic pathways. Further expert work on potato annotations will be needed with the ongoing EST and genome sequencing of potato. The current MapMan application for potato is directly applicable for analysis of data obtained on potato 10 k cDNA microarray by TIGR (The Institute for Genomic Research but can also be used

  5. Methane clumped isotopes in the Songliao Basin (China): New insights into abiotic vs. biotic hydrocarbon formation

    Science.gov (United States)

    Shuai, Yanhua; Etiope, Giuseppe; Zhang, Shuichang; Douglas, Peter M. J.; Huang, Ling; Eiler, John M.

    2018-01-01

    Abiotic hydrocarbon gas, typically generated in serpentinized ultramafic rocks and crystalline shields, has important implications for the deep biosphere, petroleum systems, the carbon cycle and astrobiology. Distinguishing abiotic gas (produced by chemical reactions like Sabatier synthesis) from biotic gas (produced from degradation of organic matter or microbial activity) is sometimes challenging because their isotopic and molecular composition may overlap. Abiotic gas has been recognized in numerous locations on the Earth, although there are no confirmed instances where it is the dominant source of commercially valuable quantities in reservoir rocks. The deep hydrocarbon reservoirs of the Xujiaweizi Depression in the Songliao Basin (China) have been considered to host significant amounts of abiotic methane. Here we report methane clumped-isotope values (Δ18) and the isotopic composition of C1-C3 alkanes, CO2 and helium of five gas samples collected from those Xujiaweizi deep reservoirs. Some geochemical features of these samples resemble previously suggested identifiers of abiotic gas (13C-enriched CH4; decrease in 13C/12C ratio with increasing carbon number for the C1-C4 alkanes; abundant, apparently non-biogenic CO2; and mantle-derived helium). However, combining these constraints with new measurements of the clumped-isotope composition of methane and careful consideration of the geological context, suggests that the Xujiaweizi depression gas is dominantly, if not exclusively, thermogenic and derived from over-mature source rocks, i.e., from catagenesis of buried organic matter at high temperatures. Methane formation temperatures suggested by clumped-isotopes (167-213 °C) are lower than magmatic gas generation processes and consistent with the maturity of local source rocks. Also, there are no geological conditions (e.g., serpentinized ultramafic rocks) that may lead to high production of H2 and thus abiotic production of CH4 via CO2 reduction. We propose

  6. Unravelling abiotic and biotic controls on the seasonal water balance using data-driven dimensionless diagnostics

    Directory of Open Access Journals (Sweden)

    S. P. Seibert

    2017-06-01

    Full Text Available The baffling diversity of runoff generation processes, alongside our sketchy understanding of how physiographic characteristics control fundamental hydrological functions of water collection, storage, and release, continue to pose major research challenges in catchment hydrology. Here, we propose innovative data-driven diagnostic signatures for overcoming the prevailing status quo in catchment inter-comparison. More specifically, we present dimensionless double mass curves (dDMC which allow inference of information on runoff generation and the water balance at the seasonal and annual timescales. By separating the vegetation and winter periods, dDMC furthermore provide information on the role of biotic and abiotic controls in seasonal runoff formation. A key aspect we address in this paper is the derivation of dimensionless expressions of fluxes which ensure the comparability of the signatures in space and time. We achieve this by using the limiting factors of a hydrological process as a scaling reference. We show that different references result in different diagnostics. As such we define two kinds of dDMC which allow us to derive seasonal runoff coefficients and to characterize dimensionless streamflow release as a function of the potential renewal rate of the soil storage. We expect these signatures for storage controlled seasonal runoff formation to remain invariant, as long as the ratios of release over supply and supply over storage capacity develop similarly in different catchments. We test the proposed methods by applying them to an operational data set comprising 22 catchments (12–166 km2 from different environments in southern Germany and hydrometeorological data from 4 hydrological years. The diagnostics are used to compare the sites and to reveal the dominant controls on runoff formation. The key findings are that dDMC are meaningful signatures for catchment runoff formation at the seasonal to annual scale and that the type of

  7. Opportunities and challenges of indigenous biotic weather forecasting among the Borena herders of southern Ethiopia.

    Science.gov (United States)

    Ayal, Desalegn Yayeh; Desta, Solomon; Gebru, Getachew; Kinyangi, James; Recha, John; Radeny, Maren

    2015-01-01

    The practical utilization of available modern as well as traditional weather forecasting systems builds herders' resiliency capacity to climatic shocks. The precision and reliability of the forecasting system determines its creditability and acceptance by the users to be proactive in the decisions they make based on the forecasted information. It has been postulated that traditional weather forecasting systems are becoming less reliable due to repeated faulty forecasts. The study assesses the current status of the Borana traditional weather forecasting system and how traditional experts make weather forecasts based on biotic indicators such as intestinal readings, changes in plant and animal body languages. Questionnaire survey, field observations, focus group discussions and interviews with relevant key informants were employed to obtain data. Collected field data was compared with National Metrological Service Agency instrumental data for consistency. Results reveal that herders made short term weather forecasts using intestinal readings, and observed changes in plant and animal body languages. The study shows the extent how public confidence in the accuracy of indigenous weather forecasting skills has been gradually eroded overtime due to faulty forecasts. The precision and credibility of the traditional weather forecast steadily declined and led to repeated faulty predictions. Poor documentation, oral based knowledge transfer system, influence of religion and modern education, aging and extinction of traditional experts were identified as the major causes undermining the vitality of traditional climate forecast. Traditional weather foresting knowledge and skill could have some utility and also serve as a starting point to scientifically study the relationship between various signs and implied climatic events. This article recommends before traditional Borana weather forecasting system completely disappears, a remedial action should be carried out to rescue this

  8. Spatial, road geometric, and biotic factors associated with Barn Owl mortality along an interstate highway

    Science.gov (United States)

    Arnold, Erin M.; Hanser, Steven E.; Regan, Tempe; Thompson, Jeremy; Lowe, Melinda; Kociolek, Angela; Belthoff, James R.

    2018-01-01

    Highway programs typically focus on reducing vehicle collisions with large mammals because of economic or safety reasons while overlooking the millions of birds that die annually from traffic. We studied wildlife‐vehicle collisions along an interstate highway in southern Idaho, USA, with among the highest reported rates of American Barn Owl Tyto furcata road mortality. Carcass data from systematic and ad hoc surveys conducted in 2004–2006 and 2013–2015 were used to explore the extent to which spatial, road geometric, and biotic factors explained Barn Owl‐vehicle collisions. Barn Owls outnumbered all other identified vertebrate species of roadkill and represented > 25% of individuals and 73.6% of road‐killed birds. At a 1‐km highway segment scale, the number of dead Barn Owls decreased with increasing numbers of human structures, cumulative length of secondary roads near the highway, and width of the highway median. Number of dead Barn Owls increased with higher commercial average annual daily traffic (CAADT), small mammal abundance index, and with grass rather than shrubs in the roadside verge. The small mammal abundance index was also greater in roadsides with grass versus mixed shrubs, suggesting that Barn Owls may be attracted to grassy portions of the highway with more abundant small mammals for hunting prey. When assessed at a 3‐km highway segment scale, the number of dead Barn Owls again increased with higher CAADT as well as with greater numbers of dairy farms. At a 5‐km scale, number of dead Barn Owls increased with greater percentage of cropland near the highway. While human conversion of the environment from natural shrub‐steppe to irrigated agriculture in this region of Idaho has likely enhanced habitat for Barns Owls, it simultaneously has increased risk for owl‐vehicle collisions where an interstate highway traverses the altered landscape. We review some approaches for highway mitigation and suggest that reducing wildlife

  9. Study of Chemical Treatment Combined with Radiation to Prepare Biotic Elicitor for Utilization in Agriculture

    International Nuclear Information System (INIS)

    Nguyen Quoc Hien

    2010-01-01

    Chitosan was prepared from shrimp shell (alpha chitosan) and from squid pen (beta chitosan) with degree of deacetylation of about 70%. Degradation of chitosan in flake form by combined treatment with H 2 O 2 and gamma Co-60 radiation was carried out. Results showed that combined treatment was highly effective for degradation of chitosan to obtain low molecular weight of 1-2 × 10 5 . Oligochitosan was prepared by irradiation of chitosan solution of 50g/l (5%, w/v). The dose required for oligochitosan with water soluble content of more than 70% was of 32kGy and 48kGy for beta and alpha chitosan, respectively. Synergic effect of degradation of chitosan in solution with H 2 O 2 and gamma Co-60 radiation was also investigated. The dose to obtain oligochitosan was reduced from 32kGy to 4kGy for beta chitosan and from 48kGy to 8kGy for alpha chitosan. The elicitation and growth promotion effect of oligochiotsan for sugarcane and rice were investigated. Results showed that oligochitosan with water soluble content of 70-80% (Mw~5,000-10,000) exhibited the most effective elicitation and growth promotion for plant. The optimum oligochitosan concentration by spraying was of 30 and 15ppm for sugarcane and rice, respectively. The disease index of Ustilgo scitaminea and Collectotrichum falcatum on sugarcane were reduced to 44.5 and 72.3% compared to control (100%). The productivity of sugarcane was increased about 13% (8tons/ha). The disease index of Pyricularia grisea on rice was reduced to 53.0% for leaf and 34.1% for neck of bloom compared to control (100%). The productivity of rice was increased for 11-26% (0.6-1.4 tons/ha). The obtained results indicated that oligochitosan is promising to use as a biotic elicitor for plant particularly for sugarcane and rice. The procedure for production of oligochitosan elicitor by γ- irradiation method was described. (author)

  10. Ecological assessment of the Tajan river using feeding groups of benthic macroinvertebrates and biotic indices

    Directory of Open Access Journals (Sweden)

    M Sharifinia

    2012-06-01

    Full Text Available One of the best practical methods to understand ecological status of a water body and determine impacts of human intervention in reducing water quality is using benthic macroinvertebrates as assessment tools for monitoring their biological integrity and health. The Tajan River is one of the rivers of Caspian Southernsub-basin that drains the Caspian Sea. Macroinvertebrate samples were taken using Surber’s sampler (40 x 40 cm and 100µ mesh size in 45 day intervals with 3 replicates in each sampling site for a period of one year (May 2010 to May 2011. The collected organisms were preserved in 4% formalin solution and transferred to the laboratory for identification and counting. Six different functional feeding groups of macroinvertebrate e.g. Collector-gathering, Collector-filtering, Predator, Collector-gathering /Scraper, Predator/Collector-gathering and Scraper were determined. Feeding groups of Collector-gathering, Collector-filtering and Collector-gathering /Scraper were relatively dominant in comparison to other groups. Groups of Collector-filtering and Collector-gathering were dominant in slightly and heavily polluted stations, respectively. In this study population structure measures including abundance, EPT percent and the EPT and EPT/CHIR indics were mearsured. Species diversity, species richness were also determined using Shannon- Weiner, Margalef and Jacardindics. The minimum and maximum values of Hilsenhoff biotic index were observedin stations 1 (4.29 and 5 (5.57, respectively. Moreover, the highest and lowest values of BMWP/ASPT were observed in station 1 (4.51 and 5 (3.25, respectively. Evaluation of indicators revealed less water quality at stations 2, 3 and 5 which located at the lowermost of fish farms and effluent of factory. This reduction might be implicated to the effluents of water damps from fish farms running into the stream as diversity and total abundance (% of sociable macroinvertebrates decreased and that of

  11. Acute dysprosium toxicity to Daphnia pulex and Hyalella azteca and development of the biotic ligand approach

    Energy Technology Data Exchange (ETDEWEB)

    Vukov, Oliver, E-mail: vuko3930@mylaurier.ca [Biology Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Smith, D. Scott [Chemistry Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); McGeer, James C. [Biology Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada)

    2016-01-15

    The toxicological understanding of rare earth elements (REEs) in the aquatic environment is very limited but of increasing concern. The objective of this research is to compare the toxicological effect of the REE dysprosium to the freshwater invertebrates Daphnia pulex and Hyalella azteca and in the more sensitive organism, understand the toxicity modifying influence of Ca, Na, Mg, pH and dissolved organic matter (DOM). Standard methods (Environment Canada) were followed for testing and culture in media of intermediate hardness (60 mg CaCO{sub 3} mg/L) at pH 7.8 with Ca at 0.5, Na 0.5, Mg 0.125 (mM) and 23 °C. Acute toxicity tests were done with <24 h old neonates for 48 h in the case of D. pulex and with 2–9 days old offspring for 96 h tests with Hyalella. The potential protective effect of cationic competition was tested with Ca (0.5–2.0 mM), Na (0.5–2.0 mM) and Mg (0.125–0.5 mM). The effect of pH (6.5–8.0) and Suwannee River DOM complexation (at dissolved organic carbon (DOC) concentrations of 9 and 13 mg C/L) were evaluated. Dissolved Dy concentrations were lower than total (unfiltered) indicating precipitation, particularly at higher concentrations. Acute toxicity of Dy to H. azteca and D. pulex revealed Hyalella to be 1.4 times more sensitive than Daphnia. Additions of Ca and Na but not Mg provided significant protection against Dy toxicity to Hyalella. Similarly, low pH was associated with reduction in toxicity. Exposures which were pH buffered with and without MOPS were significantly different and indicated that MOPS enhanced Dy toxicity. DOM also mitigated Dy toxicity. Biotic ligand based parameters (Log K values) were calculated based on free ion relationships as determined by geochemical equilibrium modeling software (WHAM ver. 7.02). The log K value for Dy{sup 3+} toxicity to Hyalella was 7.75 while the protective influence of Ca and Na were 3.95 and 4.10, respectively. This study contributes data towards the development of site specific

  12. Unravelling abiotic and biotic controls on the seasonal water balance using data-driven dimensionless diagnostics

    Science.gov (United States)

    Seibert, Simon Paul; Jackisch, Conrad; Ehret, Uwe; Pfister, Laurent; Zehe, Erwin

    2017-06-01

    The baffling diversity of runoff generation processes, alongside our sketchy understanding of how physiographic characteristics control fundamental hydrological functions of water collection, storage, and release, continue to pose major research challenges in catchment hydrology. Here, we propose innovative data-driven diagnostic signatures for overcoming the prevailing status quo in catchment inter-comparison. More specifically, we present dimensionless double mass curves (dDMC) which allow inference of information on runoff generation and the water balance at the seasonal and annual timescales. By separating the vegetation and winter periods, dDMC furthermore provide information on the role of biotic and abiotic controls in seasonal runoff formation. A key aspect we address in this paper is the derivation of dimensionless expressions of fluxes which ensure the comparability of the signatures in space and time. We achieve this by using the limiting factors of a hydrological process as a scaling reference. We show that different references result in different diagnostics. As such we define two kinds of dDMC which allow us to derive seasonal runoff coefficients and to characterize dimensionless streamflow release as a function of the potential renewal rate of the soil storage. We expect these signatures for storage controlled seasonal runoff formation to remain invariant, as long as the ratios of release over supply and supply over storage capacity develop similarly in different catchments. We test the proposed methods by applying them to an operational data set comprising 22 catchments (12-166 km2) from different environments in southern Germany and hydrometeorological data from 4 hydrological years. The diagnostics are used to compare the sites and to reveal the dominant controls on runoff formation. The key findings are that dDMC are meaningful signatures for catchment runoff formation at the seasonal to annual scale and that the type of scaling strongly

  13. Soil inoculation method determines the strength of plant-soil interactions

    NARCIS (Netherlands)

    Voorde, van de T.F.J.; Ruijten, M.; Putten, van der W.H.; Bezemer, T.M.

    2012-01-01

    There is increasing evidence that interactions between plants and biotic components of the soil influence plant productivity and plant community composition. Many plant–soil feedback experiments start from inoculating relatively small amounts of natural soil to sterilized bulk soil. These soil

  14. Cytokinins as key regulators in plant-microbe-insect interactions: connecting plant growth and defence

    NARCIS (Netherlands)

    Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

    2013-01-01

    Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. Plants are known to rapidly respond to pathogen and herbivore attack

  15. Cytokinins as key regulators in plant–microbe–insect interactions: connecting plant growth and defence

    NARCIS (Netherlands)

    Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

    2013-01-01

    1. Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. 2. Plants are known to rapidly respond to pathogen and herbivore

  16. Predicting acute copper toxicity to valve closure behavior in the freshwater clam Corbicula fluminea supports the biotic ligand model.

    Science.gov (United States)

    Liao, Chung-Min; Jou, Li-John; Lin, Chieh-Ming; Chiang, Kuo-Chin; Yeh, Ching-Hung; Chou, Berry Yun-Hua

    2007-06-01

    The objective of this paper is to employ biotic ligand model (BLM) to link between acute copper (Cu) toxicity and its effect on valve closure behavior of freshwater clam Corbicula fluminea in order to further support for the BLM that potentially offers a rapid and cost-effective method to conduct the acute toxicity tests for freshwater clam exposed to waterborne Cu. Reanalysis of published experimental data of C. fluminea closure daily rhythm and dose-response profiles based on the laboratory-acclimated clams showed that a BLM-based Hill model best described the free Cu(2+)-activity-valve closure response relationships. Our proposed Cu-BLM-Corbicula model shows that free ionic form of waterborne Cu binds specifically to a biotic ligand (i.e., clam gills) and impairs normal valve closure behavior, indicating that a fixed-level of metal accumulation at a biotic ligand is required to elicit specific biological effects. With derived mechanistic-based Cu-BLM-Corbicula model, we show that the site-specific EC50(t) and valve closure behavior at any integrated time can be well predicted, indicating that our model has the potential to develop a biomonitoring system as a bioassay tool to on-line measure waterborne Cu levels in aquatic systems. Our results confirm that BLM can be improved to analytically and rigorously describe the bioavailable fraction of metal causing toxicity to valve closure behavior in freshwater C. fluminea. We suggest that the Cu-BLM-Corbicula model can be used to assist in developing technically defensible site-specific water quality criteria and performing ecological risk assessment and to promote more focused and efficient uses of resources in the regulation and control of metals and the protection of the aquatic ecosystems.

  17. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland.

    Science.gov (United States)

    He, Wei; Choi, Ilhwan; Lee, Jung-Joon; Hur, Jin

    2016-02-15

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-CL(-1), respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS+BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Biotic transformation of anticoccidials in soil using a lab-scale bio-reactor as a precursor-tool

    DEFF Research Database (Denmark)

    Hansen, Martin; Björklund, Erland; Krogh, Kristine A

    2012-01-01

    Two anticoccidial agents, salinomycin and robenidine, heavily used in the worldwide veterinary meat production, were investigated for their potential biotic degradation by cultured soil bacteria. The degradation-study was performed in lab-scale bio-reactors under aerobic and anaerobic conditions...... incubated for 200 h with a mixed culture of soil bacteria. Samples were analyzed by LC-MS/MS and potential transformation products were tentatively identified. Salinomycin was degraded under aerobic conditions and traces could be found after 200 h, however, seems more persistent under anaerobic conditions...

  19. Epigenetic regulation of the expression of WRKY75 transcription factor in response to biotic and abiotic stresses in Solanaceae plants.

    Science.gov (United States)

    López-Galiano, María José; González-Hernández, Ana I; Crespo-Salvador, Oscar; Rausell, Carolina; Real, M Dolores; Escamilla, Mónica; Camañes, Gemma; García-Agustín, Pilar; González-Bosch, Carmen; García-Robles, Inmaculada

    2018-01-01

    SlyWRKY75: gene expression was induced in response to biotic stresses, especially in Botrytis cinerea-infected tomato plants, in which Sly-miR1127-3p is a putative SlyWRKY75 regulator and epigenetic marks were detected. WRKY75 transcription factor involved in Pi homeostasis was recently found also induced in defense against necrotrophic pathogens. In this study, we analyzed by RT-qPCR the expression of SlyWRKY75 gene in tomato plants in response to abiotic stresses (drought or heat) and biotic stresses (Colorado potato beetle larvae infestation, Pseudomonas syringae or Botrytis cinerea infection) being only differentially expressed following biotic stresses, especially upon B. cinerea infection (55-fold induction). JA and JA-Ile levels were significantly increased in tomato plants under biotic stresses compared with control plants, indicating that SlyWRKY75 might be a transcriptional regulator of the JA pathway. The contribution of miRNAs and epigenetic molecular mechanisms to the regulation of this gene in B. cinerea-infected tomato plants was explored. We identified a putative Sly-miR1127-3p miRNA predicted to bind the intronic region of the SlyWRKY75 genomic sequence. Sly-miR1127-3p miRNA was repressed in infected plants (0.4-fold) supporting that it might act as an epigenetic regulation factor of SlyWRKY75 gene expression rather than via the post-transcriptional mechanisms of canonical miRNAs. It has been proposed that certain miRNAs can mediate DNA methylation in the plant nucleus broadening miRNA functions with transcriptional gene silencing by targeting intron-containing pre-mRNAs. Histone modifications analysis by chromatin immunoprecipitation (ChIP) demonstrated the presence of the activator histone modification H3K4me3 on SlyWRKY75 transcription start site and gene body. The induction of this gene in response to B. cinerea correlates with the presence of an activator mark. Thus, miRNAs and chromatin modifications might cooperate as epigenetic factors to

  20. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

    Energy Technology Data Exchange (ETDEWEB)

    He, Wei [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of); Choi, Ilhwan [Water Analysis and Research Center, K-water, 560 Sintanjin-ro, Daedeok-gu, Daejeon 307-711 (Korea, Republic of); Lee, Jung-Joon [Department of Biological Education, Daegu University, Gyungbuk 712-714 (Korea, Republic of); Hur, Jin, E-mail: jinhur@sejong.ac.kr [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of)

    2016-02-15

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-C L{sup −1}, respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS + BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. - Highlights: • Humic fractions varied

  1. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Estimation of radiation dose to man resulting from biotic transport: the BIOPORT/MAXI1 software package. Volume 5

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, D.H.; Cadwell, L.L.; Gano, K.A.; Kennedy, W.E. Jr.; Napier, B.A.; Peloquin, R.A.; Prohammer, L.A.; Simmons, M.A.

    1985-10-01

    BIOPORT/MAXI1 is a collection of five computer codes designed to estimate the potential magnitude of the radiation dose to man resulting from biotic transport processes. Dose to man is calculated for ingestion of agricultural crops grown in contaminated soil, inhalation of resuspended radionuclides, and direct exposure to penetrating radiation resulting from the radionuclide concentrations established in the available soil surface by the biotic transport model. This document is designed as both an instructional and reference document for the BIOPORT/MAXI1 computer software package and has been written for two major audiences. The first audience includes persons concerned with the mathematical models of biological transport of commercial low-level radioactive wastes and the computer algorithms used to implement those models. The second audience includes persons concerned with exercising the computer program and exposure scenarios to obtain results for specific applications. The report contains sections describing the mathematical models, user operation of the computer programs, and program structure. Input and output for five sample problems are included. In addition, listings of the computer programs, data libraries, and dose conversion factors are provided in appendices.

  2. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Estimation of radiation dose to man resulting from biotic transport: the BIOPORT/MAXI1 software package. Volume 5

    International Nuclear Information System (INIS)

    McKenzie, D.H.; Cadwell, L.L.; Gano, K.A.; Kennedy, W.E. Jr.; Napier, B.A.; Peloquin, R.A.; Prohammer, L.A.; Simmons, M.A.

    1985-10-01

    BIOPORT/MAXI1 is a collection of five computer codes designed to estimate the potential magnitude of the radiation dose to man resulting from biotic transport processes. Dose to man is calculated for ingestion of agricultural crops grown in contaminated soil, inhalation of resuspended radionuclides, and direct exposure to penetrating radiation resulting from the radionuclide concentrations established in the available soil surface by the biotic transport model. This document is designed as both an instructional and reference document for the BIOPORT/MAXI1 computer software package and has been written for two major audiences. The first audience includes persons concerned with the mathematical models of biological transport of commercial low-level radioactive wastes and the computer algorithms used to implement those models. The second audience includes persons concerned with exercising the computer program and exposure scenarios to obtain results for specific applications. The report contains sections describing the mathematical models, user operation of the computer programs, and program structure. Input and output for five sample problems are included. In addition, listings of the computer programs, data libraries, and dose conversion factors are provided in appendices

  3. Experimentally derived acute and chronic copper Biotic Ligand Models for rainbow trout.

    Science.gov (United States)

    Crémazy, Anne; Wood, Chris M; Ng, Tania Y-T; Smith, D Scott; Chowdhury, M Jasim

    2017-11-01

    We evaluated the effects of varying water chemistry ([Ca 2+ ]=0.2-3mM, [Mg 2+ ]=0.05-3mM, dissolved organic matter (DOM, natural, from maple leaves)=0.3-10mg of CL -1 , pH=5.0-8.5) on the acute (96-h, unfed fish) and chronic (30-d, fed fish) toxicity of waterborne Cu to juvenile rainbow trout (Oncorhynchus mykiss) exposed in flow-through conditions. Acute and chronic Biotic Ligand Models (BLMs) were developed from the obtained toxicity data-sets, using the Visual MINTEQ software. Our results indicate that Cu is predominantly an acute toxicant to rainbow trout, as there were no observable growth effects and the 96-h and 30-d LC50 values were similar, with mortality mostly occurring within the first few days of exposure. Calcium and DOM were greatly protective against both acute and chronic Cu toxicity, but Mg seemed to only protect against chronic toxicity. Additional protection by pH 5.0 in acute exposure and by pH 8.5 in chronic exposure occurred. In the range of conditions tested, the observed 96-h LC50 and 30-d LC20 values varied by a factor of 39 and 27 respectively. The newly developed acute and chronic BLMs explained these variations reasonably well (i.e. within a 2-fold error), except at pH≥8 where the high observed acute toxicity could not be explained, even by considering an equal contribution of CuOH + and Cu 2+ to the overall Cu toxicity. The 96-h LC50 values of 59% of 90 toxicity tests from 19 independent studies in the literature were reasonably well predicted by the new acute BLM. The LC20 predictions from the new chronic BLM were reasonable for 7 out of 14 toxicity tests from 6 independent chronic studies (with variable exposure durations). The observed deviations from BLM predictions may be due to uncertainties in the water chemistry in these literature studies and/or to differences in fish sensitivity. A residual pH effect was also observed for both the acute and the chronic data-sets, as the ratio of predicted vs. observed LC values generally

  4. Forest tree responses to extreme drought and some biotic events: Towards a selection according to hazard tolerance?

    Science.gov (United States)

    Bréda, Nathalie; Badeau, Vincent

    2008-09-01

    The aim of this paper is to illustrate how some extreme events could affect forest ecosystems. Forest tree response can be analysed using dendroecological methods, as tree-ring widths are strongly controlled by climatic or biotic events. Years with such events induce similar tree responses and are called pointer years. They can result from extreme climatic events like frost, a heat wave, spring water logging, drought or insect damage… Forest tree species showed contrasting responses to climatic hazards, depending on their sensitivity to water shortage or temperature hardening, as illustrated from our dendrochronological database. For foresters, a drought or a pest disease is an extreme event if visible and durable symptoms are induced (leaf discolouration, leaf loss, perennial organs mortality, tree dieback and mortality). These symptoms here are shown, lagging one or several years behind a climatic or biotic event, from forest decline cases in progress since the 2003 drought or attributed to previous severe droughts or defoliations in France. Tree growth or vitality recovery is illustrated, and the functional interpretation of the long lasting memory of trees is discussed. A coupled approach linking dendrochronology and ecophysiology helps in discussing vulnerability of forest stands, and suggests management advices in order to mitigate extreme drought and cope with selective mortality.

  5. A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link

    Science.gov (United States)

    Smith, E. F.; Nelson, L. L.; Tweedt, S. M.; Zeng, H.; Workman, Jeremiah B.

    2017-01-01

    Owing to the lack of temporally well-constrained Ediacaran fossil localities containing overlapping biotic assemblages, it has remained uncertain if the latest Ediacaran (ca 550–541 Ma) assemblages reflect systematic biological turnover or environmental, taphonomic or biogeographic biases. Here, we report new latest Ediacaran fossil discoveries from the lower member of the Wood Canyon Formation in Nye County, Nevada, including the first figured reports of erniettomorphs, Gaojiashania, Conotubus and other problematic fossils. The fossils are spectacularly preserved in three taphonomic windows and occur in greater than 11 stratigraphic horizons, all of which are below the first appearance of Treptichnus pedum and the nadir of a large negative δ13C excursion that is a chemostratigraphic marker of the Ediacaran–Cambrian boundary. The co-occurrence of morphologically diverse tubular fossils and erniettomorphs in Nevada provides a biostratigraphic link among latest Ediacaran fossil localities globally. Integrated with a new report of Gaojiashania from Namibia, previous fossil reports and existing age constraints, these finds demonstrate a distinctive late Ediacaran fossil assemblage comprising at least two groups of macroscopic organisms with dissimilar body plans that ecologically and temporally overlapped for at least 6 Myr at the close of the Ediacaran Period. This cosmopolitan biotic assemblage disappeared from the fossil record at the end of the Ediacaran Period, prior to the Cambrian radiation.

  6. Impact of biotic and abiotic stresses on the competitive ability of multiple herbicide resistant wild oat (Avena fatua).

    Science.gov (United States)

    Lehnhoff, Erik A; Keith, Barbara K; Dyer, William E; Menalled, Fabian D

    2013-01-01

    Ecological theory predicts that fitness costs of herbicide resistance should lead to the reduced relative abundance of resistant populations upon the cessation of herbicide use. This greenhouse research investigated the potential fitness costs of two multiple herbicide resistant (MHR) wild oat (Avena fatua) populations, an economically important weed that affects cereal and pulse crop production in the Northern Great Plains of North America. We compared the competitive ability of two MHR and two herbicide susceptible (HS) A. fatua populations along a gradient of biotic and abiotic stresses The biotic stress was imposed by three levels of wheat (Triticum aestivum) competition (0, 4, and 8 individuals pot(-1)) and an abiotic stress by three nitrogen (N) fertilization rates (0, 50 and 100 kg N ha(-1)). Data were analyzed with linear mixed-effects models and results showed that the biomass of all A. fatua populations decreased with increasing T. aestivum competition at all N rates. Similarly, A. fatua relative growth rate (RGR) decreased with increasing T. aestivum competition at the medium and high N rates but there was no response with 0 N. There were no differences between the levels of biomass or RGR of HS and MHR populations in response to T. aestivum competition. Overall, the results indicate that MHR does not confer growth-related fitness costs in these A. fatua populations, and that their relative abundance will not be diminished with respect to HS populations in the absence of herbicide treatment.

  7. Alternative Oxidase: A Mitochondrial Respiratory Pathway to Maintain Metabolic and Signaling Homeostasis during Abiotic and Biotic Stress in Plants

    Directory of Open Access Journals (Sweden)

    Greg C. Vanlerberghe

    2013-03-01

    Full Text Available Alternative oxidase (AOX is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. While respiratory carbon oxidation pathways, electron transport, and ATP turnover are tightly coupled processes, AOX provides a means to relax this coupling, thus providing a degree of metabolic homeostasis to carbon and energy metabolism. Beside their role in primary metabolism, plant mitochondria also act as “signaling organelles”, able to influence processes such as nuclear gene expression. AOX activity can control the level of potential mitochondrial signaling molecules such as superoxide, nitric oxide and important redox couples. In this way, AOX also provides a degree of signaling homeostasis to the organelle. Evidence suggests that AOX function in metabolic and signaling homeostasis is particularly important during stress. These include abiotic stresses such as low temperature, drought, and nutrient deficiency, as well as biotic stresses such as bacterial infection. This review provides an introduction to the genetic and biochemical control of AOX respiration, as well as providing generalized examples of how AOX activity can provide metabolic and signaling homeostasis. This review also examines abiotic and biotic stresses in which AOX respiration has been critically evaluated, and considers the overall role of AOX in growth and stress tolerance.

  8. A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link.

    Science.gov (United States)

    Smith, E F; Nelson, L L; Tweedt, S M; Zeng, H; Workman, J B

    2017-07-12

    Owing to the lack of temporally well-constrained Ediacaran fossil localities containing overlapping biotic assemblages, it has remained uncertain if the latest Ediacaran ( ca 550-541 Ma) assemblages reflect systematic biological turnover or environmental, taphonomic or biogeographic biases. Here, we report new latest Ediacaran fossil discoveries from the lower member of the Wood Canyon Formation in Nye County, Nevada, including the first figured reports of erniettomorphs, Gaojiashania , Conotubus and other problematic fossils. The fossils are spectacularly preserved in three taphonomic windows and occur in greater than 11 stratigraphic horizons, all of which are below the first appearance of Treptichnus pedum and the nadir of a large negative δ 13 C excursion that is a chemostratigraphic marker of the Ediacaran-Cambrian boundary. The co-occurrence of morphologically diverse tubular fossils and erniettomorphs in Nevada provides a biostratigraphic link among latest Ediacaran fossil localities globally. Integrated with a new report of Gaojiashania from Namibia, previous fossil reports and existing age constraints, these finds demonstrate a distinctive late Ediacaran fossil assemblage comprising at least two groups of macroscopic organisms with dissimilar body plans that ecologically and temporally overlapped for at least 6 Myr at the close of the Ediacaran Period. This cosmopolitan biotic assemblage disappeared from the fossil record at the end of the Ediacaran Period, prior to the Cambrian radiation. © 2017 The Author(s).

  9. TaWRKY68 responses to biotic stresses are revealed by the orthologous genes from major cereals

    Directory of Open Access Journals (Sweden)

    Bo Ding

    2014-01-01

    Full Text Available WRKY transcription factors have been extensively characterized in the past 20 years, but in wheat, studies onWRKY genes and their function are lagging behind many other species. To explore the function of wheat WRKY genes, we identified a TaWRKY68 gene from a common wheat cultivar. It encodes a protein comprising 313 amino acids which harbors 19 conserved motifs or active sites. Gene expression patterns were determined by analyzing microarray data of TaWRKY68 in wheat and of orthologous genes from maize, rice and barley using Genevestigator. TaWRKY68 orthologs were identified and clustered using DELTA-BLAST and COBALT programs available at NCBI. The results showed that these genes, which are expressed in all tissues tested, had relatively higher levels in the roots and were up-regulated in response to biotic stresses. Bioinformatics results were confirmed by RT-PCR experiments using wheat plants infected by Agrobacterium tumefaciens and Blumeria graminis, or treated with Deoxynivalenol, a Fusarium graminearum-induced mycotoxin in wheat or barley. In summary,TaWRKY68 functions differ during plant developmental stages and might be representing a hub gene function in wheat responses to various biotic stresses. It was also found that including data from major cereal genes in the bioinformatics analysis gave more accurate and comprehensive predictions of wheat gene functions.

  10. The community diversity of two Caribbean MPAs invaded by lionfish does not support the biotic resistance hypothesis

    Science.gov (United States)

    Cobián-Rojas, Dorka; Schmitter-Soto, Juan J.; Aguilar Betancourt, Consuelo M.; Aguilar-Perera, Alfonso; Ruiz-Zárate, Miguel Á.; González-Sansón, Gaspar; Chevalier Monteagudo, Pedro P.; Herrera Pavón, Roberto; García Rodríguez, Alain; Corrada Wong, Raúl I.; Cabrera Guerra, Delmis; Salvat Torres, Héctor; Perera Valderrama, Susana

    2018-04-01

    Marine protected areas (MPAs) conserve diversity and abundance of fish communities. According to the biotic resistance hypothesis, communities with higher diversity and abundance should resist invasions better. To test this idea, the presence of lionfish in two Caribbean MPAs was studied: Parque Nacional Guanahacabibes (PNG) in Cuba and Parque Nacional Arrecifes de Xcalak (PNAX) in Mexico. Selection of these MPAs was based on both their different levels of success with enforcement and different abundances of native fish, with a more abundant native fish fauna at PNG. Underwater visual censuses were used to evaluate both the native fish structure and composition and at the same time distribution and abundance of lionfish. The abundance of potential predators on lionfish was also measured to determine possible effects of lionfish on both the abundance and the size of its prey and competitors. Lionfish showed higher abundance and larger size in PNG compared to PNAX, even though its probable competitors and predators were also more abundant and larger in PNG. Prey abundance and size decreased after the invasion. No correlation was detected between potential predators and lionfish, which might indicate natural predation is not substantial. In PNAX, lower abundance of prey, potential competitors and predators can also be attributed to historical overfishing, but this did not provide an advantage to lionfish. Lionfish were less abundant and reached smaller sizes in PNAX compared to PNG. This work confirms the effectiveness of lionfish culling at PNAX, but does not support the biotic resistence hypothesis that native fish might have controlled this invasive species.

  11. Genome-wide analysis of Dof transcription factors reveals functional characteristics during development and response to biotic stresses in pepper

    Science.gov (United States)

    Kang, Won-Hee; Kim, Seungill; Lee, Hyun-Ah; Choi, Doil; Yeom, Seon-In

    2016-01-01

    The DNA-binding with one zinc finger proteins (Dofs) are a plant-specific family of transcription factors. The Dofs are involved in a variety of biological processes such as phytohormone production, seed development, and environmental adaptation. Dofs have been previously identified in several plants, but not in pepper. We identified 33 putative Dof genes in pepper (CaDofs). To gain an overview of the CaDofs, we analyzed phylogenetic relationships, protein motifs, and evolutionary history. We divided the 33 CaDofs, containing 25 motifs, into four major groups distributed on eight chromosomes. We discovered an expansion of the CaDofs dated to a recent duplication event. Segmental duplication that occurred before the speciation of the Solanaceae lineages was predominant among the CaDofs. The global gene-expression profiling of the CaDofs by RNA-seq analysis showed distinct temporal and pathogen-specific variation during development and response to biotic stresses (two TMV strains, PepMoV, and Phytophthora capsici), suggesting functional diversity among the CaDofs. These results will provide the useful clues into the responses of Dofs in biotic stresses and promote a better understanding of their multiple function in pepper and other species. PMID:27653666

  12. [Biotic and abiotic determinants of seroprevalence of antibodies against Trypanosoma cruzi in Palmar de Bravo, Puebla, Mexico].

    Science.gov (United States)

    Sosa-Jurado, Francisca; Zumaquero-Ríos, José Lino; Reyes, Pedro A; Cruz-García, Abel; Guzmán-Bracho, Carmen; Monteón, Victor M

    2004-01-01

    To establish the relationship between seroprevalence for antibodies against Trypanosoma cruzi and its relationship with biotic and abiotic factors. A cross-sectional study was conducted between August 2000 and September 2001. The study population consisted of a simple random sample of 390 volunteers residing in Palmar de Bravo, Puebla, Mexico. Sample and data collection procedures included assaying antibodies against T. cruzi with validated assays, and searching for domestic reservoirs and triatomine bugs. The relationship between biotic and abiotic factors with seropositivity was assessed. Statistical analysis was conducted using Kappa values for diagnostic tests; statistical significance was assessed with 2 x 2 tables, chi-squared test with Yates' correction, Fisher exact test, and odds ratios. The seroprevalence of T. cruzi infection in humans was 4%; in domestic reservoirs (horses, pigs, and dogs) only 10% of canine reservoirs were positive. Vector species recognized were T. borberi and T. pallidipennis, with a Dispersion Area Index and a Colonization Index of 55% and 40%, respectively. The most important risk factors associated with positive serology were altitude (>2,150 and <2,180 meters above sea level), presence of triatomines, age, time of residence, and participation in a social assistance program. T. cruzi infection was identified in human beings, vectors, and possibly in domestic reservoirs, in communities located over 2,000 meters above sea level.

  13. Scale Expansion of Community Investigations and Integration of the Effects of Abiotic and Biotic Processes on Maintenance of Species Diversity

    Directory of Open Access Journals (Sweden)

    Zhenhong Wang

    2011-01-01

    Full Text Available Information on the maintenance of diversity patterns from regional to local scales is dispersed among academic fields due to the local focus of community ecology. To better understand these patterns, the study of ecological communities needs to be expanded to larger scales and the various processes affecting them need to be integrated using a suitable quantitative method. We determined a range of communities on a flora-subregional scale in Yunnan province, China (383210.02 km2. A series of species pools were delimited from the regional to plot scales. Plant diversity was evaluated and abiotic and biotic processes identified at each pool level. The species pool effect was calculated using an innovative model, and the contribution of these processes to the maintenance of plant species diversity was determined and integrated: climate had the greatest effect at the flora-subregional scale, with historical and evolutionary processes contributing ∼11%; climate and human disturbance had the greatest effect at the local site pool scale; competition exclusion and stress limitation explained strong filtering at the successional stage pool scale; biotic processes contributed more on the local community scale than on the regional scale. Scale expansion combined with the filtering model approach solves the local problem in community ecology.

  14. Use of a macroinvertebrate based biotic index to estimate critical metal concentrations for good ecological water quality.

    Science.gov (United States)

    Van Ael, Evy; De Cooman, Ward; Blust, Ronny; Bervoets, Lieven

    2015-01-01

    Large datasets from total and dissolved metal concentrations in Flemish (Belgium) fresh water systems and the associated macroinvertebrate-based biotic index MMIF (Multimetric Macroinvertebrate Index Flanders) were used to estimate critical metal concentrations for good ecological water quality, as imposed by the European Water Framework Directive (2000). The contribution of different stressors (metals and water characteristics) to the MMIF were studied by constructing generalized linear mixed effect models. Comparison between estimated critical concentrations and the European and Flemish EQS, shows that the EQS for As, Cd, Cu and Zn seem to be sufficient to reach a good ecological quality status as expressed by the invertebrate-based biotic index. In contrast, the EQS for Cr, Hg and Pb are higher than the estimated critical concentrations, which suggests that when environmental concentrations are at the same level as the EQS a good quality status might not be reached. The construction of mixed models that included metal concentrations in their structure did not lead to a significant outcome. However, mixed models showed the primary importance of water characteristics (oxygen level, temperature, ammonium concentration and conductivity) for the MMIF. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Study on the Changes of Biotic Variables, Their Influence on the Primary Productivity and the Effect of Manuring of Fish Ponds

    Directory of Open Access Journals (Sweden)

    Doychin I. Terziyski

    2016-12-01

    Full Text Available The experiment was carried out in the period 2004-2006 on seven fish ponds of the Institute for Fishery and Aquaculture in Plovdiv city, Bulgaria with a single area varying from 1.8 to 3.9 daа. Powered fertilization with cattle manure on dose 3000 kg.ha-1 was applied. The aim of the experiment was to studythe relations between the biotic factors (zooplankton, phytoplankton, zoobenthos, chlorophyll a, macrophytes, bacterioplankton, percent of energy utilization by primary productivity (PEU, their influence on the primary productivity and the effect of manuring on the fish ponds. The bigger part of the biotic factor variation was defined by the differences between the monthly samplings compared to the changes between the ponds within the period of investigation (2004/05/06. There was a difference between the first and last months concerning the biotic factors. This great seasonal variability decreases the opportunity for revealing the differences between the manured and the control ponds. The biotic factors as the PP (primary productivity, respiration and PEU in the manured ponds were higher compared to the control ponds during 2005. More macrophytes and higher PP/respiration and PP/chlorophyllа ratioswere detected in the control ponds. Increased biotic variable values of the PP, respiration and chlorophyll а were found in the manured ponds during 2006. The derived relationships might contribute for enhanced productivity of carp ponds and for improvement of existing management practices in the view of better water quality in fish farming.

  16. Extended biotic ligand model for predicting combined Cu-Zn toxicity to wheat (Triticum aestivum L.): Incorporating the effects of concentration ratio, major cations and pH.

    Science.gov (United States)

    Wang, Xuedong; Ji, Dongxue; Chen, Xiaolin; Ma, Yibing; Yang, Junxing; Ma, Jingxing; Li, Xiaoxiu

    2017-11-01

    Current risk assessment models for metals such as the biotic ligand model (BLM) are usually applied to individual metals, yet toxic metals are rarely found singly in the environment. In the present research, the toxicity of Cu and Zn alone and together were studied in wheat (Triticum aestivum L.) using different Ca 2+ and Mg 2+ concentrations, pH levels and Zn:Cu concentration ratios. The aim of the study was to better understand the toxicity effects of these two metals using BLMs and toxic units (TUs) from single and combined metal toxicity data. The results of single-metal toxicity tests showed that toxicity of Cu and Zn tended to decrease with increasing Ca 2+ or Mg 2+ concentrations, and that the effects of pH on Cu and Zn toxicity were related not only to free Cu 2+ and Zn 2+ activity, respectively, but also to other inorganic metal complex species. For the metal mixture, Cu-Zn interactions based on free ion activities were primarily additive for the different Ca 2+ and Mg 2+ concentrations and levels of pH. The toxicity data of individual metals derived by the BLM, which incorporated Ca 2+ and Mg 2+ competition and toxicity of inorganic met