WorldWideScience

Sample records for terrestrial plant communities

  1. Broad-Scale Comparison of Photosynthesis in Terrestrial and Aquatic Plant Communities

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Krause-Jensen, D.

    1997-01-01

    Comparisons of photosynthesis in terrestrial and aquatic habitats have been impaired by differences in methods and time-scales of measurements. We compiled information on gross photosynthesis at high irradiance and photosynthetic efficiency at low irradiance from 109 published terrestrial studies...... communities probably due to more efficient light utilization and gas exchange in the terrestrial habitats. By contrast only small differences were found within different aquatic plant communities or within different terrestrial plant communities....... of forests, grasslands and crops and 319 aquatic studies of phytoplankton, macrophyte and attached microalgal communities to test if specific differences existed between the communities. Maximum gross photosynthesis and photosynthetic efficiency were systematically higher in terrestrial than in aquatic...

  2. [Plant communities in the terrestrial-aquatic transition zone in the paramo of Chingaza, Colombia].

    Science.gov (United States)

    Schmidt-Mumm, Udo; Vargas Ríos, Orlando

    2012-03-01

    Plant communities in the terrestrial-aquatic transition zone in the paramo of Chingaza, Colombia. High Andean paramo ecosystems are an important water resource for many towns, and major cities in this region. The aquatic and wetland vegetation of different paramo lakes, pond, swamps and bogs was studied according to the classical phytosociological approach, which is based on homogenous stands, but excludes any border phenomena or transitional zone. The present research aimed at determining the aquatic and wetland vegetation along different moisture gradients. A total of 89 species in 30 transects were reported, of which Crassula venezuelensis, Carex honplandii, Callitriche nubigena, Eleocharis macrostachya, Ranunculus flagelliformis, R. nubigenus, Eleocharis stenocarpa, Galium ascendens y Alopecurus aequalis were present in more than one third of the transects. Numerical classification and indicator species analysis resulted in the definition of the next 18 communities: 1) Calamagrostis effusa, 2) Sphagnum cuspidatum, 3) Cyperus rufus, 4) Eleocharis stenocarpa, 5) Carex acutata, 6) Poa annua,7) Valeriana sp., 8) Ranunculus flagelliformis, 9) Carex bonplandii, 10) Festuca andicola. 11) Muhlenbergia fustigiata, 12) Elatine paramoana, 13) Isoëtes palmeri, 14) Crassula venezuelensis, 15) Lilaeopsis macloviana, 16) Callitriche nubigena, 17) Potamogeton paramoanus and 18) Potamogeton illinoensis. The ordination of communities reveals the presence of three different aquatic-terrestrial gradients which are related to the life form structure of species that characterized the various communities. We concluded that patchiness and heterogeneity of the vegetation is mainly the result of alterations caused by human activities (burning, cattle raise and material extraction for road and dam construction).

  3. A Preliminary Survey of Terrestrial Plant Communities in the Sierra de los Valles

    Energy Technology Data Exchange (ETDEWEB)

    Randy G. Balice

    1998-10-01

    To more fully understand the species compositions and environmental relationships of high-elevation terrestrial plant communities in the Los Alamos region, 30 plots in randomly selected, upland locations were sampled for vegetation, topographic, and soils characteristics. The locations of these plots were constrained to be above 2,134 m (7,000 ft) above mean sea level. The field results were summarized, analyzed, and incorporated into a previously developed classification of vegetation and land cover types. The revised and updated discussions of the environmental relationships at these sites and their associated species compositions are included in this report. A key to the major land cover types in the Los Alamos region was also revised in accordance with the new information and included herein its entirety.

  4. Terrestrial plant methane production

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Møller, Ian M.

    We evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants. We conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH4 production, i.e. cutting injuries, increasing temperature...... the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  5. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 1).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. The paper does not provide guidelines but rather...

  6. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 2).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described in a series of appendices. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. ...

  7. The effect of glyphosate and nitrogen on plant communities and the soil fauna in terrestrial biotopes at field margins

    DEFF Research Database (Denmark)

    Damgaard, Christian; Strandberg, Beate; Dupont, Yoko

    were assessed at the ecosystem level by measuring biodiversity and functional traits. We have obtained an increased understanding of the causal relationship between plant communities and the soil fauna at the ecosystem level and increased knowledge on how and by what mechanisms important drivers...... that are known to affect plant communities may affect pollination and the soil fauna. The combined use of plant trait and soil fauna trait data in a full-factorial field experiment of glyphosate and nitrogen has never been explored before. The focus on plant and soil fauna traits rather than species enabled...... nitrogen, generally, resulted in increasing total plant cover and biomass, especially of fast-growing and competitive species as grasses and a few herbs such as Tanacetum vulgare. Using plant traits we found that increase in nitrogen promoted an increase in the average specific leaf area (SLA) and canopy...

  8. Methane emissions form terrestrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, P.; Dentener, F.; Grassi, G.; Leip, A.; Somogyi, Z.; Federici, S.; Seufert, G.; Raes, F. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

    2006-07-01

    In a recent issue of Nature Keppler et al. (2006) report the discovery that terrestrial plants emit CH4 under aerobic conditions. Until now it was thought that bacterial decomposition of plant material under anaerobic conditions, such as in wetlands and water flooded rice paddies, is the main process leading to emissions from terrestrial ecosystems. In a first attempt to upscale these measurements, the authors estimate that global total emissions may be 149 Tg CH4/yr (62-236 Tg CH4/yr), with the main contribution estimated from tropical forests and grasslands (107 Tg CH4/yr with a range of 46-169 Tg CH4/yr). If confirmed, this new source of emission would constitute a significant fraction of the total global methane sources (estimated 500-600 Tg CH4/yr for present day total natural and anthropogenic sources) and have important implications for the global CH4 budget. To accommodate it within the present budget some sources would need to be re-assessed downwards and/or some sinks re-assessed upwards. Furthermore, also considering that methane is a {approx}23 times more powerful greenhouse gas than CO2, the possible feedbacks of these hitherto unknown CH4 emissions on global warming and their impacts on greenhouse gases (GHG) mitigation strategies need to be carefully evaluated. The merit of the paper is without doubt related to the remarkable discovery of a new process of methane emissions active under aerobic conditions. However, we think that the applied approach of scaling up emissions from the leaf level to global totals by using only few measured data (mainly from herbaceous species) and the Net Primary Productivity of the main biomes is scientifically questionable and tends to overestimate considerably the global estimates, especially for forest biomes. Furthermore, some significant constraints on the upper limit of the global natural CH4 emissions arise from the pre-industrial CH4 budget. Pre-industrial atmospheric CH4 mixing ratios have been measured

  9. The soil and plant determinants of community structures of the dominant actinobacteria in Marion Island terrestrial habitats, Sub-Antarctica

    CSIR Research Space (South Africa)

    Sanyika, TW

    2012-08-01

    Full Text Available Marion Island is a Sub-Antarctic island made up of distinct ecological habitats based on soil physiochemical, plant cover and physical characteristics. The microbial diversity and ecological determinants in this harsh Sub-Antarctic environment...

  10. Pollen and spores of terrestrial plants

    Science.gov (United States)

    Bernhardt, Christopher E.; Willard, Debra A.; Shennan, Ian; Long, Antony J.; Horton, Benjamin P.

    2015-01-01

    Pollen and spores are valuable tools in reconstructing past sea level and climate because of their ubiquity, abundance, and durability as well as their reciprocity with source vegetation to environmental change (Cronin, 1999; Traverse, 2007; Willard and Bernhardt, 2011). Pollan is found in many sedimentary environments, from freshwater to saltwater, terrestrial to marine. It can be abundant in a minimal amount of sample material, for example half a gram, as concentrations can be as high as four million grains per gram (Traverse, 2007). The abundance of pollen in a sample lends it to robust statistical analysis for the quantitative reconstruction of environments. The outer cell wall is resistant to decay in sediments and allows palynomorphs (pollen and spores) to record changes in plant communities and sea level over millions of years. These characteristics make pollen and spores a powerful tool to use in sea-level research.This chapter describes the biology of pollen and spores and how they are transported and preserved in sediments. We present a methodology for isolating pollen from sediments and a general language and framework to identify pollen as well as light micrographs of a selection of common pollen grains, We then discuss their utility in sea-level research.

  11. Terrestrial plant methane production and emission

    DEFF Research Database (Denmark)

    Bruhn, Dan; Møller, Ian M.; Mikkelsen, Teis Nørgaard

    2012-01-01

    In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce...... aerobic CH4 into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  12. How lichens impact on terrestrial community and ecosystem properties.

    Science.gov (United States)

    Asplund, Johan; Wardle, David A

    2017-08-01

    Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include

  13. Electrochemical Power Plant for Terrestrial Flight Platforms, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An electrochemical power plant is proposed by MicroCell Technologies to provide power to terrestrial flight platforms. Our power plant is based upon a proton...

  14. Terrestrial radiation level in selected asphalt plants in Port Harcourt ...

    African Journals Online (AJOL)

    Terrestrial radiation level in selected asphalt plants in Port Harcourt, Nigeria. ... An environmental radiation survey in asphalt processing plants in Rivers State was been carried out ... Therefore the results show significant radiological risk.

  15. MBS Native Plant Communities

    Data.gov (United States)

    Minnesota Department of Natural Resources — This data layer contains results of the Minnesota County Biological Survey (MCBS). It includes polygons representing the highest quality native plant communities...

  16. Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, @iDerris scandens@@ (Dicotyledonae:Leguminocae)

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Sonak, S.; Garg, A.

    Methanol extract of terrestrial plant, @iDerris scandens@@ Benth, was found to inhibit growth of four diatoms and 7 bacterial species of fouling community. The concentrations required to bring about 100% inhibition of growth of the diatoms ranged...

  17. Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, Derris scandens (Dicotyledonae:Leguminocae)

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Sonak, S.; Garg, A.

    Methanol extract of terrestrial plant, Derris scandens Benth, was found to inhibit growth of four diatoms and 7 bacterial species of fouling community. The concentrations required to bring about 100% inhibition of growth of the diatoms ranged...

  18. [Feasibility study for whole plant medicinal use of Tribulus terrestris].

    Science.gov (United States)

    Yang, Li; Wang, Chunyu; Han, Meiw; Yang, Limin

    2009-09-01

    The content differences of leaf, plant and fruit of Tribulus terrestris was compared to study the feasibility of whole plant medicinal use. The samples were collected in three typical habitats and six different production areas of T. terrestris. The main medicinal ingredients saponins and flavonoids were determined in root, stem, leaf and fruit during the harvest time. The two ingredients were abounded in leaf and more than 2.61 times as in other parts of the plant. The results showed that there were no differences between the whole plant and the fruit. It should pay more attentions on the collection, preservation and utilization of the leaf of T. terrestris in the harvesting and processing stage. The whole plant for medical use was feasibility based on the content of the ingredients.

  19. Microbial rhodopsins on leaf surfaces of terrestrial plants

    OpenAIRE

    Atamna-Ismaeel, Nof; Finkel, Omri M.; Glaser, Fabian; Sharon, Itai; Schneider, Ron; Post, Anton F.; Spudich, John L.; von Mering, Christian; Vorholt, Julia A.; Iluz, David; Béjà, Oded; Belkin, Shimshon

    2011-01-01

    The above-ground surfaces of terrestrial plants, the phyllosphere, comprise the main interface between the terrestrial biosphere and solar radiation. It is estimated to host up to 1026 microbial cells that may intercept part of the photon flux impinging on the leaves. Based on 454-pyrosequencing-generated metagenome data, we report on the existence of diverse microbial rhodopsins in five distinct phyllospheres from tamarisk (Tamarix nilotica), soybean (Glycine max), Arabidopsis (Arabidopsis t...

  20. Evaluation of radiological doses to the terrestrial plants around Trombay

    International Nuclear Information System (INIS)

    Ajay Kumar; Singhal, R.K.; Preetha, J.; Joshi, S.N.; Hegde, A.G.

    2005-01-01

    Existing policies for radiation protection do not provide explicit criteria for the protection of species other than humans, i.e. not for flora and fauna. Concern over this omission is now being widely expressed and moves are under way to evaluate the doses to terrestrial and aquatic biota. During the present work radiological doses (external and internal) to the terrestrial plants were evaluated by estimating the concentration of anthropogenic ( 137 Cs, 90 Sr) and natural radionuclides ( 238 U, 232 Th and 40 K) in the plant leaves and by measuring the external gamma radiation due to different radionuclide. The soil and vegetation sample were collected from fifteen sampling locations around the different locations at Trombay. The samples were processed as per IAEA (International Atomic Energy Agency) protocol for the estimation of naturally occurring and anthropogenic radionuclides in soil and terrestrial plants. The gamma emitting radionuclides were measured by high resolution gamma (HPGe) spectrometry system. Maximum exposure (external + internal) to the terrestrial plants was observed due to 232 Th while 238 U showed minimum exposure. The average value of radiation exposure to the terrestrial plants for 40 K, 137 Cs, 90 Sr, 238 U and 232 Th was 1555.2 ± 92.4, 691.2 ± 54.3, 2564.1 ± 534.9, 82.5 ±5.2, and 4419.6 ± 1165.5 μGy/y respectively. The radiation exposure (external + internal ) to the terrestrial plants due to all radionuclides was found within the permissible limits (i.e. 10 mGy/d) as per recommended by the United States, Department of Energy (DOE). (author)

  1. Plant ABC transporters enable many unique aspects of a terrestrial plant's lifestyle

    DEFF Research Database (Denmark)

    Hwang, Jae-Ung; Song, Won-Yong; Hong, Daewoong

    2016-01-01

    Terrestrial plants have two to four times more ATP-binding cassette (ABC) transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental...... to propose that diverse ABC transporters enabled many unique and essential aspects of a terrestrial plant's lifestyle, by transporting various compounds across specific membranes of the plant....

  2. Terrestrial Analogs to Mars: NRC Community Panel Decadal Report

    Science.gov (United States)

    Farr, T. G.

    2002-12-01

    A report was completed recently by a Community Panel for the NRC Decadal Study of Solar System Exploration. The desire was for a review of the current state of knowledge and for recommendations for action over the next decade. The topic of this panel, Terrestrial Analogs to Mars, was chosen to bring attention to the need for an increase in analog studies in support of the increased pace of Mars exploration. It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of martian meteorites), and computer and laboratory modeling. The combination of all of these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the overarching science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel considered the issues of data collection and archiving, value of field workshops, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities. Parts of this work were performed under contract to NASA.

  3. Community Decadal Panel for Terrestrial Analogs to Mars

    Science.gov (United States)

    Barlow, N. G.; Farr, T.; Baker, V. R.; Bridges, N.; Carsey, F.; Duxbury, N.; Gilmore, M. S.; Green, J. R.; Grin, E.; Hansen, V.; Keszthelyi, L.; Lanagan, P.; Lentz, R.; Marinangeli, L.; Morris, P. A.; Ori, G. G.; Paillou, P.; Robinson, C.; Thomson, B.

    2001-11-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites for Mars, instrument tests, laboratory measurements (including analysis of martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel is considering the following two key questions: (1) How do terrestrial analog studies tie in to the MEPAG science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel is considering the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  4. Degradation of Total Petroleum Hydrocarbon in Phytoremediation Using Terrestrial Plants

    Directory of Open Access Journals (Sweden)

    Mushrifah Idris

    2014-06-01

    Full Text Available This study focused on the total petroleum hydrocarbon (TPH degradation in phytoremediation of spiked diesel in sand. The diesel was added to the sand that was planted with terrestrial plants. Four selected terrestrial plants used were Paspalum vaginatum Sw, Paspalums crobiculatum L. varbispicatum Hack, Eragrotis atrovirens (Desf. Trin. ex Steud and Cayratia trifolia (L. Domin since all the plants could survive at a hydrocarbon petroleum contaminated site in Malaysia. The samplings were carried out on Day 0, 7, 14, 28, 42 and 72. The analysis of the TPH was conducted by extracting the spiked sand using ultrasonic extraction. The determination of the TPH concentration in the sand was performed using GC-FID. The degradation of TPH depends on the plant species and time of exposure. The highest percentage degradation by P. vaginatum, P. scrobiculatum, E. atrovirens and C. trifolia were 91.9, 74.0, 68.9 and 62.9%, respectively. In conclusion, the ability to degrade TPH by plants were P. vaginatum > P. scrobiculatum > E. atrovirens> C. trifolia.

  5. A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

    Science.gov (United States)

    Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

    2013-01-01

    We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational, and/or modeling studies have the potential to overcome important caveats of the respective individual approaches. © 2012 Blackwell Publishing Ltd.

  6. Terrestrial plants: a potent source for isolation of eco-friendly antifouling compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Wagh, A.B.

    by number of workers in the past. However, little attention is paid towards terrestrial plants. In light of this some selected plants have been screened for antifouling activity. These plants are Acacia pennata and Barringtonia acutangula. These plants...

  7. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L; Doug Martin, D; Michael Paller, M; Eric Nelson, E

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here. This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.

  8. Physical injury stimulates aerobic methane emissions from terrestrial plants

    Directory of Open Access Journals (Sweden)

    Z.-P. Wang

    2009-04-01

    Full Text Available Physical injury is common in terrestrial plants as a result of grazing, harvesting, trampling, and extreme weather events. Previous studies demonstrated enhanced emission of non-microbial CH4 under aerobic conditions from plant tissues when they were exposed to increasing UV radiation and temperature. Since physical injury is also a form of environmental stress, we sought to determine whether it would also affect CH4 emissions from plants. Physical injury (cutting stimulated CH4 emission from fresh twigs of Artemisia species under aerobic conditions. More cutting resulted in more CH4 emissions. Hypoxia also enhanced CH4 emission from both uncut and cut Artemisia frigida twigs. Physical injury typically results in cell wall degradation, which may either stimulate formation of reactive oxygen species (ROS or decrease scavenging of them. Increased ROS activity might explain increased CH4 emission in response to physical injury and other forms of stress. There were significant differences in CH4 emissions among 10 species of Artemisia, with some species emitting no detectable CH4 under any circumstances. Consequently, CH4 emissions may be species-dependent and therefore difficult to estimate in nature based on total plant biomass. Our results and those of previous studies suggest that a variety of environmental stresses stimulate CH4 emission from a wide variety of plant species. Global change processes, including climate change, depletion of stratospheric ozone, increasing ground-level ozone, spread of plant pests, and land-use changes, could cause more stress in plants on a global scale, potentially stimulating more CH4 emission globally.

  9. Plant volatiles in extreme terrestrial and marine environments.

    Science.gov (United States)

    Rinnan, Riikka; Steinke, Michael; McGenity, Terry; Loreto, Francesco

    2014-08-01

    This review summarizes the current understanding on plant and algal volatile organic compound (VOC) production and emission in extreme environments, where temperature, water availability, salinity or other environmental factors pose stress on vegetation. Here, the extreme environments include terrestrial systems, such as arctic tundra, deserts, CO₂ springs and wetlands, and marine systems such as sea ice, tidal rock pools and hypersaline environments, with mangroves and salt marshes at the land-sea interface. The emission potentials at fixed temperature and light level or actual emission rates for phototrophs in extreme environments are frequently higher than for organisms from less stressful environments. For example, plants from the arctic tundra appear to have higher emission potentials for isoprenoids than temperate species, and hypersaline marine habitats contribute to global dimethyl sulphide (DMS) emissions in significant amounts. DMS emissions are more widespread than previously considered, for example, in salt marshes and some desert plants. The reason for widespread VOC, especially isoprenoid, emissions from different extreme environments deserves further attention, as these compounds may have important roles in stress resistance and adaptation to extremes. Climate warming is likely to significantly increase VOC emissions from extreme environments both by direct effects on VOC production and volatility, and indirectly by altering the composition of the vegetation. © 2014 John Wiley & Sons Ltd.

  10. Using Ant Communities For Rapid Assessment Of Terrestrial Ecosystem Health

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L

    2005-06-01

    relative health of the ecosystem. The IBI, though originally for Midwestern streams, has been successfully adapted to other ecoregions and taxa (macroinvertebrates, Lombard and Goldstein, 2004) and has become an important tool for scientists and regulatory agencies alike in determining health of stream ecosystems. The IBI is a specific type of a larger group of methods and procedures referred to as Rapid Bioassessment (RBA). These protocols have the advantage of directly measuring the organisms affected by system perturbations, thus providing an integrated evaluation of system health because the organisms themselves integrate all aspects of their environment and its condition. In addition to the IBI, the RBA concept has also been applied to seep wetlands (Paller et al. 2005) and terrestrial systems (O'Connell et al. 1998, Kremen et al. 1993, Rodriguez et al. 1998, Rosenberg et al. 1986). Terrestrial RBA methods have lagged somewhat behind those for aquatic systems because terrestrial systems are less distinctly defined and seem to have a less universal distribution of an all-inclusive taxon, such as fish in the IBI, upon which to base an RBA. In the last decade, primarily in Australia, extensive development of an RBA using ant communities has shown great promise. Ants have the same advantage for terrestrial RBAs that fish do for aquatic systems in that they are an essential and ubiquitous component of virtually all terrestrial ecosystems. They occupy a broad range of niches, functional groups, and trophic levels and they possess one very important characteristic that makes them ideal for RBA because, similar to the fishes, there is a wide range of tolerance to conditions within the larger taxa. Within ant communities there are certain groups, genera, or species that may be very robust and abundant under even the harshest impacts. There are also taxa that are very sensitive to disturbance and change and their presence or absence is also indicative of the local

  11. The effects of glyphosate and aminopyralid on an artifical plant communities

    Science.gov (United States)

    The US EPA has responsibility for registration of pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The potential adverse effects of pesticides to nontarget terrestrial plant communities are a concern that must be addressed in the pesticide regist...

  12. Future of Plant Functional Types in Terrestrial Biosphere Models

    Science.gov (United States)

    Wullschleger, S. D.; Euskirchen, E. S.; Iversen, C. M.; Rogers, A.; Serbin, S.

    2015-12-01

    Earth system models describe the physical, chemical, and biological processes that govern our global climate. While it is difficult to single out one component as being more important than another in these sophisticated models, terrestrial vegetation is a critical player in the biogeochemical and biophysical dynamics of the Earth system. There is much debate, however, as to how plant diversity and function should be represented in these models. Plant functional types (PFTs) have been adopted by modelers to represent broad groupings of plant species that share similar characteristics (e.g. growth form) and roles (e.g. photosynthetic pathway) in ecosystem function. In this review the PFT concept is traced from its origin in the early 1800s to its current use in regional and global dynamic vegetation models (DVMs). Special attention is given to the representation and parameterization of PFTs and to validation and benchmarking of predicted patterns of vegetation distribution in high-latitude ecosystems. These ecosystems are sensitive to changing climate and thus provide a useful test case for model-based simulations of past, current, and future distribution of vegetation. Models that incorporate the PFT concept predict many of the emerging patterns of vegetation change in tundra and boreal forests, given known processes of tree mortality, treeline migration, and shrub expansion. However, representation of above- and especially belowground traits for specific PFTs continues to be problematic. Potential solutions include developing trait databases and replacing fixed parameters for PFTs with formulations based on trait co-variance and empirical trait-environment relationships. Surprisingly, despite being important to land-atmosphere interactions of carbon, water, and energy, PFTs such as moss and lichen are largely absent from DVMs. Close collaboration among those involved in modelling with the disciplines of taxonomy, biogeography, ecology, and remote sensing will be

  13. Divergent composition but similar function of soil food webs of individual plants: plant species and community effects

    NARCIS (Netherlands)

    Bezemer, T.M.; Fountain, T.; Barea, J.M.; Christensen, S.; Dekker, S.C.; Duyts, H.; Hal, van R.; Harvey, J.A.; Hedlund, K.; Maraun, M.; Mikola, J.; Mladenov, A.G.; Robin, C.; Ruiter, de P.C.; Scheu, H.; Setälä, S.; šmilauer, P.; Putten, van der W.H.

    2010-01-01

    Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and

  14. Divergent composition but similar function of soil food webs beneath individual plants: plant species and community effects

    NARCIS (Netherlands)

    Bezemer, T.M.; Fountain, M.T.; Barea, J.M.; Christensen, S.; Dekker, S.C.; Duyts, H.; van Hal, R.; Harvey, J.A.; Hedlund, K.; Maraun, M.; Mikola, J.; Mladenov, A.G.; Robin, C.; de Ruiter, P.C.; Scheu, S.; Setälä, H.; Milauer, P.; Van der Putten, W.H.

    2010-01-01

    Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and

  15. Mean residence times for tritium in some terrestrial plants

    International Nuclear Information System (INIS)

    Gogate, S.S.; Krishnamoorthy, T.M.; Soman, S.D.

    1975-01-01

    Uptake of tritiated water from a single or multiple exposure, its fixation and elimination from 3 terrestrial plants, Raphanus sativus L., Amaranthus viridis L. and Phyllanthus fraternus Webster under experimental field conditions are described. Tissue free water tritium (TFWT) attains peak concentration within 4 hr after a single exposure in R. sativus and then decreases with a single component from both leaves and root, with a biological half-time of 36.4 +- 4.2 and 48.5 +- 7.2 hr respectively. TFWT in leaves of A. viridis reaches its peak value within 0.5 hr of exposure and its decay exhibits 2 component fall, one having a very short half-life of 2.4 +- 0.7 hr and the other a long half-time of 86.1 +- 2.0 hr. The two component decay of tritium in TFWT is well represented in P. fraternus. The long-lived components are nearly 8 times of the short-lived ones, both in leaves and stems respectively. Generally, the long -lived component accounts for 15% of the peak TFWT. Tissue bound tritium (TBT) reaches to 4% of TFWT in Phyllanthus sp. TBT elimination time is many times longer than the experimental periods employed in the present study. (author)

  16. Mountain Plant Community Sentinels: AWOL

    Science.gov (United States)

    Malanson, G. P.

    2017-12-01

    Mountain plant communities are thought to be sensitive to climate change. Because climatic gradients are steep on mountain slopes, the spatial response of plant communities to climate change should be compressed and easier to detect. These expectations have led to identifying mountain plant communities as sentinels for climate change. This idea has, however, been criticized. Two critiques, for alpine treeline and alpine tundra, are rehearsed and supplemented. The critique of alpine treeline as sentinel is bolstered with new model results on the confounding role of dispersal mechanisms and sensitivity to climatic volatility. In alpine tundra, for which background turnover rates have yet to be established, community composition may reflect environmental gradients only for extremes where effects of climate are most indirect. Both plant communities, while primarily determined by energy at broad scales, may respond to water as a proximate driver at local scales. These plant communities may not be in equilibrium with climate, and differently scaled time lags may mean that ongoing vegetation change may not signal ongoing climate change (or lack thereof). In both cases a double-whammy is created by scale dependence for time lags and for drivers leading to confusion, but these cases present opportunities for insights into basic ecology.

  17. Implications of sensor configuration and topography on vertical plant profiles derived from terrestrial LiDAR

    NARCIS (Netherlands)

    Calders, K.; Armston, J.; Newnham, G.; Herold, M.; Goodwin, N.

    2014-01-01

    The vertical distribution of plant constituents is a key parameter to describe vegetation structure and influences several processes, such as radiation interception, growth and habitat. Terrestrial laser scanning (TLS), also referred to as terrestrial LiDAR, has the potential to measure the canopy

  18. Effects of spray drift of glyphosate on nontarget terrestrial plants-A critical review.

    Science.gov (United States)

    Cederlund, Harald

    2017-11-01

    Glyphosate is a widely used broad-spectrum postemergent herbicide used for weed control in both agricultural and nonagricultural settings. Spray drift of glyphosate can pose a risk to nontarget terrestrial plants and plant communities outside the intended area of application, but the lack of a well-established predicted-no-effect drift rate makes properly assessing such risk difficult. For this reason, a literature review and meta-analysis was carried out with the aim to determine the level of drift that is likely to cause harm to plants and to explore what spray-reducing targets would be sufficiently protective. No-observed-adverse effect rates, lowest-observed-adverse effect rates, and effect rates giving 10, 25, and 50% effects were extracted from a total of 39 different publications. The data were combined per species, and species sensitivity distributions were constructed and fitted with a log-logistic model to assess protectiveness. No systematic differences were detected between the responses of monocotyledons or dicotyledons, but wild plants were found to be generally less sensitive to glyphosate drift than domesticated plants. The results indicate that restricting spray drift to a level below 5 g a.e./ha would protect approximately 95% of all higher plant species against minor adverse effects of glyphosate drift and that rates below 1 to 2 g a.e./ha would be almost completely protective. No studies were encountered that evaluated effects of spray drift against nonvascular plants, and therefore, the conclusions are only valid for vascular plants. Environ Toxicol Chem 2017;36:2879-2886. © 2017 SETAC. © 2017 SETAC.

  19. A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability

    Science.gov (United States)

    Reyer, C.; Leuzinger, S.; Rammig, A.; Wolf, A.; Bartholomeus, R. P.; Bonfante, A.; de Lorenzi, F.; Dury, M.; Gloning, P.; Abou Jaoudé, R.; Klein, T.; Kuster, T. M.; Martins, M.; Niedrist, G.; Riccardi, M.; Wohlfahrt, G.; de Angelis, P.; de Dato, G.; François, L.; Menzel, A.; Pereira, M.

    2013-01-01

    We review observational, experimental and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied but potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heatwaves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational and /or modeling studies have the potential to overcome important caveats of the respective individual approaches. PMID:23504722

  20. Community attitudes toward nuclear plants

    International Nuclear Information System (INIS)

    Peelle, E.

    1982-01-01

    Among the many effects of the accident at Three Mile Island are impacts upon other communities that currently host nuclear-power reactors. Because studies on communities' reactions not immediately available, this chapter reviews existing studies and speculates about possible effects. The patterns and variations in impacts on and responses of nuclear host communities have been the subject of studies at Oak Ridge National Laboratory (Oak Ridge, Tennessee) since 1972. This essay presents results from four post-licensing studies of host communities - Plymouth, Massachusetts, and Waterford, Connecticut (PL-1), and Brunswick, North Carolina, and Appling-Toombs counties, Georgia (PL-2) - along with case study and attitude survey information from two additional communities in which reactors are under construction: Hartsville, Tennessee, and Cherokee County, South Carolina. Differences and similarities between the sites have been assessed in terms of differences in input and social structure; factors affecting the generally favorable attitudes toward local nuclear plants are discussed

  1. Acclimation of a terrestrial plant to submergence facilitates gas exchange under water

    NARCIS (Netherlands)

    Mommer, L.; Pedersen, O.; Visser, E.J.W.

    2004-01-01

    Flooding imposes stress upon terrestrial plants since it severely hampers gas exchange rates between the shoot and the environment. The resulting oxygen deficiency is considered to be the major problem for submerged plants. Oxygen microelectrode studies have, however, shown that aquatic plants

  2. Acclimation of a terrestrial plant to submergence facilitates gas exchange under water

    DEFF Research Database (Denmark)

    Mommer, L.; Pedersen, O.; Visser, E. J. W.

    2004-01-01

    Flooding imposes stress upon terrestrial plants since it severely hampers gas exchange rates between the shoot and the environment. The resulting oxygen deficiency is considered to be the major problem for submerged plants. Oxygen microelectrode studies have, however, shown that aquatic plants...... of this terrestrial plant species to submergence for gas exchange capacity is also shown. Shoot acclimation to submergence involved a reduction of the diffusion resistance to gases, which was not only functional by increasing diffusion of oxygen into the plant, but also by increasing influx of CO2, which enhances...... maintain relatively high internal oxygen pressures under water, and even may release oxygen via the roots into the sediment, also in dark. Based on these results, we challenge the dogma that oxygen pressures in submerged terrestrial plants immediately drop to levels at which aerobic respiration is impaired...

  3. Microbial plant litter decomposition in aquatic and terrestrial boreal systems along a natural fertility gradient

    Science.gov (United States)

    Soares, A. Margarida P. M.; Kritzberg, Emma S.; Rousk, Johannes

    2017-04-01

    Plant litter decomposition is a global ecosystem process, with a crucial role in carbon and nutrient cycling. The majority of litter processing occurs in terrestrial systems, but an important fraction also takes place in inland waters. Among environmental factors, pH impacts the litter decomposition through its selective influence on microbial decomposers. Fungal communities are less affected by pH than bacteria, possibly owing to a wider pH tolerance by this group. On the other hand, bacterial pH optima are constrained to a narrower range of pH values. The microbial decomposition of litter is universally nutrient limited; but few comparisons exist between terrestrial and aquatic systems. We investigated the microbial colonisation and decomposition of plant litter along a fertility gradient, which varied in both pH and N availability in both soil and adjacent water. To do this we installed litterbags with birch (Betula pendula) in streams and corresponding soils in adjacent riparian areas in a boreal system, in Krycklan, Sweden. During the four months covering the ice-free growth season we monitored the successional dynamics of fungal (acetate incorporation into ergosterol) and bacterial growth (thymidine incorporation), microbial respiration in leaf litter, and quantitative and qualitative changes in litter over time. We observed that bacterial growth rates were initially higher in litter decomposing in streams than those in soils, but differences between terrestrial and aquatic bacterial production converged towards the end of the experiment. In litter bags installed in soils, bacterial growth was lower at sites with more acidic pH and lower N availability, while aquatic bacteria were relatively unaffected by the fertility level. Fungal growth rates were two-fold higher for litter decomposing in streams than in soils. In aquatic systems, fungal growth was initially lower in low fertility sites, but differences gradually disappeared over the time course. Fungal

  4. Effects of chlorimuron ethyl on terrestrial and wetland plants: Levels of, and time to recovery following sublethal exposure

    International Nuclear Information System (INIS)

    Carpenter, David; Boutin, Céline; Allison, Jane E.

    2013-01-01

    Current pesticide registration guidelines call for short-term testing of plants; long-term effects on vegetative parts and reproduction remain untested. The aims of our study were to determine level of recovery and recovery times for plants exposed to the sulfonylurea herbicide chlorimuron ethyl using data collected from single species, dose–response greenhouse experiments. The nine terrestrial and eight wetland species tested showed variable levels of recovery and recovery timeframes. Many species (six terrestrial and five wetland) were vegetatively stunted at sublethal doses and were reproductively impaired. Full recovery did not occur at all doses and maximum recovery times varied from 3 to 15 weeks in this controlled environment. In a complex community, affected species may be displaced by tolerant species, through interspecific competition, before they fully recover. It is plausible that individual populations could be diminished or eliminated through reduced seedbank inputs (annuals and perennials) and asexual reproduction (perennials). - Highlights: ► Native terrestrial and wetland plants were used to assess the risks of herbicide drift. ► Vegetative and reproductive health endpoints were evaluated over time. ► Recovery rates were found to be both species and dose dependant. ► Reproductive recovery does not always equal vegetative recovery. ► Susceptible species may be displaced by resilient or resistant species. - Capsule: This study serves to bridge the gap between simplified short-term greenhouse tests and effects of herbicides on recovery of non-target plant species after sublethal exposures.

  5. Effects of plant diversity on primary production and species interactions in brackish water angiosperm communities

    DEFF Research Database (Denmark)

    Salo, Tiina; Gustafsson, Camilla; Boström, Christoffer

    2009-01-01

    Research on plant biodiversity and ecosystem functioning has mainly focused on terrestrial ecosystems, and our understanding of how plant species diversity and interactions affect processes in marine ecosystems is still limited. To investigate if plant species richness and composition influence...... plant productivity in brackish water angiosperm communities, a 14 wk field experiment was conducted. Using a replacement design with a standardized initial aboveground biomass, shoots of Zostera marina, Potamogeton filiformis and P. perfoliatus were planted on a shallow, sandy bottom in replicated...

  6. Moving forward on facilitation research : Response to changing environments and effects on the diversity, functioning and evolution of plant communities

    NARCIS (Netherlands)

    Soliveres, Santiago; Smit, Christian; Maestre, Fernando T

    Once seen as anomalous, facilitative interactions among plants and their importance for community structure and functioning are now widely recognized. The growing body of modelling, descriptive and experimental studies on facilitation covers a wide variety of terrestrial and aquatic systems

  7. Plant community responses to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kongstad, J.

    2012-07-01

    Climate change is expected to affect terrestrial ecosystems across the globe with increased atmospheric CO{sub 2} concentration, higher temperatures and changes in precipitation patterns. These environmental factors are drivers of many important ecosystem processes, and changes in ecosystem function are therefore expected in the future. The aim of this PhD-thesis was to examine the effects of climate change on aboveground plant growth, plant composition and plant phenology in Danish heathland ecosystems. Two sites were investigated in large-scale field experiments: 1) the CLIMAITE site, 'Brandbjerg' and 2) the INCREASE site at Mols. Field manipulations lasted years and included: Warming, summer drought and (CLIMAITE only) elevated CO{sub 2} concentrations. The treatments were applied individually and in all possible combinations. Further, at Brandbjerg, but outside the treatment plots, a study was performed on the effects nitrogen and phosphorus addition on phenology, chemistry and growth of the dominant grass Deschampsia flexuosa (Wavy Hairgrass). In general, the aboveground vegetation responded less than expected to changing climatic conditions; even though Calluna vulgaris (Heather) increased in biomass over the study period, the biomass was not affected by the manipulations, indicating that C. vulgaris, has a strong resistance to changes in climate. Also, the grass biomass (primarily D. flexuosa) was not affected and was relatively constant over the period. I argue that the resilience of D. flexuosa towards the climatic treatments came from the plants ability to let the tissue die back, and then quickly recover once conditions again became favourable. That gave the plant a high resilience to changes in climatic factors. Calluna vulgaris, on the other hand, showed a resistance to changes by constantly maintaining the growth during the whole season, probably because of its evergreen status. Together, the two different strategies made the heathland

  8. Down-regulation of tissue N:P ratios in terrestrial plants by elevated CO2.

    Science.gov (United States)

    Deng, Qi; Hui, Dafeng; Luo, Yiqi; Elser, James; Wang, Ying-ping; Loladze, Irakli; Zhang, Quanfa; Dennis, Sam

    2015-12-01

    Increasing atmospheric CO2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO2 impact on plant nitrogen: phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO2 had lower N:P ratios in both above- and belowground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO2-induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO2 and of the underlying mechanisms affecting nutrient dynamics under climate change.

  9. Determinants of terrestrial arthropod community composition at Cape Hallett, Antarctica

    CSIR Research Space (South Africa)

    Sinclair, BJ

    2006-09-01

    Full Text Available . wadei. Arthropods were absent from areas occupied by the large Adelie penguin colony. There was some distinction among arthropod communities of different habitats, with water and a lichen species (indicative of scree slope habitats) ranking...

  10. Herbivory and growth in terrestrial and aquatic populations of amphibious stream plants

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Jacobsen, Dean

    2002-01-01

    1. Many amphibious plant species grow in the transition between terrestrial and submerged vegetation in small lowland streams. We determined biomass development, leaf turnover rate and invertebrate herbivory during summer in terrestrial and aquatic populations of three amphibious species...... production (average 1.2-5.1%) than aquatic populations (2.9-17.3%), while the same plant dry mass was consumed per unit ground area. 3. Grazing loss increased linearly with leaf age apart from the youngest leaf stages. Grazing loss during the lifetime of leaves was therefore 2.4-3.1 times higher than mean...... apparent loss to standing leaves of all ages. The results imply that variation in density of grazers relative to plant production can account for differences in grazing impact between terrestrial and aquatic populations, and that fast leaf turnover keeps apparent grazing damage down. 4. We conclude...

  11. Communities of terrestrial nematodes after different approaches to heathland restoration

    Science.gov (United States)

    Radochova, Petra; Frouz, Jan

    2016-04-01

    Since the 20th century, the distribution of European heathlands rapidly decreased due to agricultural intensification, heavy use of artificial fertilizers or acidification (Aerts & Heil, 1993). Therefore, various attempts of heathland restoration are under way in these days. Analysis of nematode community composition can be one of the tools suitable for succession evaluation (Ferris et al., 2001). In 2011, 2013 and 2014, soil samples were collected from heathland restoration experiment (launched in 2011) where different restoration methods were applied in a 3 × 3 factorial experiment; existing heathlands were also sampled to identify the target community both in dry and wet heathland. A total of 60 samples of extracted nematodes were analysed for absolute abundance, trophic groups, and genera dominance. Various indices were calculated to describe the nematode community. We were able to prove faster development of wet heathlands towards the target community. However, because of large data variability, there was no significant difference between treatments. Development of wet and dry heathlands differed also in increased proportion of omniphagous nematodes in 2013 and predators in 2014 in dry heathlands. After three years of heathland restoration, nematode community has not yet reached parameters of the target community. References Aerts, R., Heil, G. W., 1993. Heathlands: patterns and processes in a changing environment, 1st ed, Geobotany: 20. Springer Netherlands, Dordrecht, p. 229. Ferris, H., Bongers, T., De Goede, R. G. M., 2001. A framework for soil food web diagnostics: Extension of the nematode faunal analysis oncept. Appl. Soil Ecol. 18, 13-29.

  12. Gas exchange under water. Acclimation of terrestrial plants to submergence

    NARCIS (Netherlands)

    Mommer, L.

    2005-01-01

    Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be prolonged photosynthesis under water, but this has received only little

  13. Effects of increased solar ultraviolet radiation on terrestrial plants

    International Nuclear Information System (INIS)

    Caldwell, M.M.; Teramura, A.H.; Tevini, M.; Bornman, J.F.; Björn, L.O.; Kulandaivelu, G.

    1995-01-01

    Physiological and developmental processes of plants are affected by UV-B radiation, even by the amount of UV-B in present-day sunlight. Plants also have several mechanisms to ameliorate or repair these effects and may acclimate to a certain extent to increased levels of UV-B. Nevertheless, plant growth can be directly affected by UV-B radiation. Response to UV-B also varies considerably among species and also cultivars of the same species. In agriculture, this may necessitate using more UV-B-tolerant cultivars and breeding new ones. In forests and grasslands, this will likely result in changes in species composition; therefore there are implications for the biodiversity in different ecosystems. Indirect changes caused by UV-B-such as changes in plant form, biomass allocation to parts of the plant, timing of developmental phases and secondary metabolism-may be equally, or sometimes more important than damaging effects of UV-B. These changes can have important implications for plant competitive balance, herbivory, plant pathogens, and biogeochemical cycles. These ecosystem-level effects can be anticipated, but not easily predicted or evaluated. Research at the ecosystem level for solar UV-B is barely beginning. Other factors, including those involved in climate change such as increasing CO2, also interact with UV-B. Such reactions are not easily predicted, but are of obvious importance in both agriculture and in nonagricultural ecosystems

  14. Plant diversity and plant identity influence Fusarium communities in soil.

    Science.gov (United States)

    LeBlanc, Nicholas; Kinkel, Linda; Kistler, H Corby

    2017-01-01

    Fusarium communities play important functional roles in soil and in plants as pathogens, endophytes, and saprotrophs. This study tests how rhizosphere Fusarium communities may vary with plant species, changes in the diversity of the surrounding plant community, and soil physiochemical characteristics. Fusarium communities in soil associated with the roots of two perennial prairie plant species maintained as monocultures or growing within polyculture plant communities were characterized using targeted metagenomics. Amplicon libraries targeting the RPB2 locus were generated from rhizosphere soil DNAs and sequenced using pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs) and assigned a taxonomy using the Evolutionary Placement Algorithm. Fusarium community composition was differentiated between monoculture and polyculture plant communities, and by plant species in monoculture, but not in polyculture. Taxonomic classification of the Fusarium OTUs showed a predominance of F. tricinctum and F. oxysporum as well of the presence of a clade previously only found in the Southern Hemisphere. Total Fusarium richness was not affected by changes in plant community richness or correlated with soil physiochemical characteristics. However, OTU richness within two predominant phylogenetic lineages within the genus was positively or negatively correlated with soil physiochemical characteristics among samples within each lineage. This work shows that plant species, plant community richness, and soil physiochemical characteristics may all influence the composition and richness of Fusarium communities in soil.

  15. Ecological succession reveals potential signatures of marine-terrestrial transition in salt marsh fungal communities

    NARCIS (Netherlands)

    Dini-Andreote, Francisco; Pylro, Victor Satler; Baldrian, Petr; van Elsas, Jan Dirk; Salles, Joana Falcão

    Marine-to-terrestrial transition represents one of the most fundamental shifts in microbial life. Understanding the distribution and drivers of soil microbial communities across coastal ecosystems is critical given the roles of microbes in soil biogeochemistry and their multifaceted influence on

  16. TERRESTRIAL PLANT REPRODUCTIVE TESTING: SHOULD WILDLIFE TOXICOLOGISTS CARE?

    Science.gov (United States)

    Standard phytotoxicity testing using the seedling emergence and vegetative vigor tests have been shown to be inadequate for the protection of plant reproduction. Both experimental evidence and unintended field exposures have shown vegetation can be minimally or not significantly...

  17. Terrestrial biogeochemistry in the community climate system model (CCSM)

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Forrest [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6016 (United States); Fung, Inez [University of California at Berkeley, Berkeley, California (United States); Randerson, Jim [University of California at Irvine, Irvine, California (United States); Thornton, Peter [National Center for Atmospheric Research, Boulder, Colorado (United States); Foley, Jon [University of Wisconsin at Madison, Madison, Wisconsin (United States); Covey, Curtis [Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, California (United States); John, Jasmin [University of California at Berkeley, Berkeley, California (United States); Levis, Samuel [National Center for Atmospheric Research, Boulder, Colorado (United States); Post, W Mac [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6016 (United States); Vertenstein, Mariana [National Center for Atmospheric Research, Boulder, Colorado (United States); Stoeckli, Reto [Colorado State University, Ft. Collins, Colorado (United States); Running, Steve [University of Montana, Missoula, Montana (United States); Heinsch, Faith Ann [University of Montana, Missoula, Montana (United States); Erickson, David [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6016 (United States); Drake, John [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6016 (United States)

    2006-09-15

    Described here is the formulation of the CASA{sup '} biogeochemistry model of Fung, et al., which has recently been coupled to the Community Land Model Version 3 (CLM3) and the Community Climate System Model Version 3 (CCSM3). This model is presently being used for Coupled Climate/Carbon Cycle Model Intercomparison Project (C{sup 4}MIP) Phase 1 experiments. In addition, CASA{sup '} is one of three models - in addition to CN (Thornton, et al.) and IBIS (Thompson, et al.) - that are being run within CCSM to investigate their suitability for use in climate change predictions in a future version of CCSM. All of these biogeochemistry experiments are being performed on the Computational Climate Science End Station (Dr. Warren Washington, Principle Investigator) at the National Center for Computational Sciences at Oak Ridge National Laboratory.

  18. Terrestrial biogeochemistry in the community climate system model (CCSM)

    International Nuclear Information System (INIS)

    Hoffman, Forrest; Fung, Inez; Randerson, Jim; Thornton, Peter; Foley, Jon; Covey, Curtis; John, Jasmin; Levis, Samuel; Post, W Mac; Vertenstein, Mariana; Stoeckli, Reto; Running, Steve; Heinsch, Faith Ann; Erickson, David; Drake, John

    2006-01-01

    Described here is the formulation of the CASA ' biogeochemistry model of Fung, et al., which has recently been coupled to the Community Land Model Version 3 (CLM3) and the Community Climate System Model Version 3 (CCSM3). This model is presently being used for Coupled Climate/Carbon Cycle Model Intercomparison Project (C 4 MIP) Phase 1 experiments. In addition, CASA ' is one of three models - in addition to CN (Thornton, et al.) and IBIS (Thompson, et al.) - that are being run within CCSM to investigate their suitability for use in climate change predictions in a future version of CCSM. All of these biogeochemistry experiments are being performed on the Computational Climate Science End Station (Dr. Warren Washington, Principle Investigator) at the National Center for Computational Sciences at Oak Ridge National Laboratory

  19. Underwater photosynthesis in flooded terrestrial plants: a matter of leaf plasticity

    NARCIS (Netherlands)

    Mommer, L.; Visser, E.J.W.

    2005-01-01

    • Background Flooding causes substantial stress for terrestrial plants, particularly if the floodwater completely submerges the shoot. The main problems during submergence are shortage of oxygen due to the slow diffusion rates of gases in water, and depletion of carbohydrates, which is the substrate

  20. A functional comparison of acclimation to shade and submergence in two terrestrial plant species

    NARCIS (Netherlands)

    Mommer, L.; Kroon, de H.; Pierik, R.; bögemann, G.M.; Visser, E.J.W.

    2005-01-01

    Terrestrial plants experience multiple stresses when they are submerged, caused both by oxygen deficiency due to reduced gas diffusion in water, and by shade due to high turbidity of the floodwater. It has been suggested that responses to submergence are de facto responses to low light intensity. •

  1. Ecophysiological traits of terrestrial and aquatic carnivorous plants: are the costs and benefits the same?

    Czech Academy of Sciences Publication Activity Database

    Ellison, A. M.; Adamec, Lubomír

    2011-01-01

    Roč. 120, č. 11 (2011), 1721-1731 ISSN 0030-1299 Institutional research plan: CEZ:AV0Z60050516 Keywords : terrestrial and aquatic carnivorous plants * photosynthesis * mineral nutrition Subject RIV: EF - Botanics Impact factor: 3.061, year: 2011

  2. Embracing community ecology in plant microbiome research

    NARCIS (Netherlands)

    Dini-Andreote, F.; Raaijmakers, J.M.

    2018-01-01

    Community assembly is mediated by selection, dispersal, drift, and speciation. Environmental selection is mostly used to date to explain patterns in plant microbiome assembly, whereas the influence of the other processes remains largely elusive. Recent studies highlight that adopting community

  3. Preservation of terrestrial plant biomarkers from Nachukui Formation sediments and their viability for stable isotope analysis

    Science.gov (United States)

    Kahle, E.; Uno, K. T.; Polissar, P. J.; Lepre, C. J.; deMenocal, P. B.

    2013-12-01

    Plio-Pleistocene sedimentary records from the Turkana Basin in eastern Africa provide a unique opportunity to compare a high-resolution record of climate and terrestrial vegetation with important changes in the record of human evolution. Molecular biomarkers from terrestrial vegetation can yield stable isotope ratios of hydrogen and carbon that reflect ancient climate and vegetation. However, the preservation of long-chain plant wax biomarkers in these paleosol, fluvial, and lacustrine sediments is not known, and this preservation must be studied to establish their utility for molecular stable isotope studies. We investigated leaf wax biomarkers in Nachukui Formation sediments deposited between 2.3 and 1.7 Ma to assess biomarker preservation. We analyzed n alkane and n alkanoic acid concentrations and, where suitable, molecular carbon and hydrogen isotope ratios. Molecular abundance distributions show a great deal of variance in biomarker preservation and plant-type source as indicated by the carbon preference index and average chain length. This variation suggests that some samples are suitable for isotopic analysis, while other samples lack primary terrestrial plant biomarker signatures. The biomarker signal in many samples contains significant additional material from unidentified sources. For example, the n-alkane distributions contain an unresolved complex mixture underlying the short and mid-chain n-alkanes. Samples from lacustrine intervals include long-chain diacids, hydroxy acids and (ω-1) ketoacids that suggest degradation of the original acids. Degradation of poorly preserved samples and the addition of non-terrestrial plant biomarkers may originate from a number of processes including forest fire or microbial alteration. Isotopic analysis of well-preserved terrestrial plant biomarkers will be presented along with examples where the original biomarker distribution has been altered.

  4. Solar radiation uncorks the lignin bottleneck on plant litter decomposition in terrestrial ecosystems

    Science.gov (United States)

    Austin, A.; Ballare, C. L.; Méndez, M. S.

    2015-12-01

    Plant litter decomposition is an essential process in the first stages of carbon and nutrient turnover in terrestrial ecosystems, and together with soil microbial biomass, provide the principal inputs of carbon for the formation of soil organic matter. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in low rainfall ecosystems; however, the generality of this process as a control on carbon cycling in terrestrial ecosystems is not known, and the indirect effects of photodegradation on biotic stimulation of carbon turnover have been debated in recent studies. We demonstrate that in a wide range of plant species, previous exposure to solar radiation, and visible light in particular, enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility for microbial enzymes to plant litter carbohydrates due to a reduction in lignin content. Photodegradation of plant litter reduces the structural and chemical bottleneck imposed by lignin in secondary cell walls. In litter from woody plant species, specific interactions with ultraviolet radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized positive effect of solar radiation exposure on subsequent microbial activity is mediated by increased accessibility to cell wall polysaccharides, which suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release and the carbon balance in a broad range of terrestrial ecosystems.

  5. Nutrients, Toxins, and Water in Terrestrial and Aquatic Ecosystems Treated with Sewage Plant Effluents. Final Report of the Upland Recharge Program

    Energy Technology Data Exchange (ETDEWEB)

    Woodwell, G. M.; Ballard, J. T.; Clinton, J.; Pecan, E. V.

    1976-01-01

    The objective of this work was to appraise the capacity of terrestrial and aquatic plant communities for absorbing and retaining nutrients and organic matter in sewage and for releasing ''clean'' water. Experimental systems included a sere representative of the Eastern Deciduous Forest, a timothy field, two Phalaris arundinacea meadows, a freshwater marsh, a pond, and a marsh-pond complex. Sewage of two qualities was applied at the rate of 5 cm per week; one treatment was equivalent to the release from a primary treatment sewage plant, the second to that from a secondary treatment plant. Under normal circumstances, without the addition of water or nutrients in sewage, the flux of nutrients into the groundwater was greatest under the agricultural communities and least under the late successional forest communities. All the terrestrial communities were net sources of most elements. Because the agricultural communities were fertilized and a substantial fraction of the fertilizer applied remained after the first year, the agricultural communities appeared to be net sinks during the first year of the experiment. The highest concentrations of nutrients in the percolate of the untreated communities commonly occurred in the earliest stages of succession. This relationship was especially conspicuous for nitrogen. Phosphorus and iron appeared to be held tightly within most ecosystems.

  6. Risk assessment considerations for plant protection products and terrestrial life-stages of amphibians.

    Science.gov (United States)

    Weltje, Lennart; Ufer, Andreas; Hamer, Mick; Sowig, Peter; Demmig, Sandra; Dechet, Friedrich

    2018-04-28

    Some amphibians occur in agricultural landscapes during certain periods of their life cycle and consequently might be exposed to plant protection products (PPPs). While the sensitivity of aquatic life-stages is considered to be covered by the standard assessment for aquatic organisms (especially fish), the situation is less clear for terrestrial amphibian life-stages. In this paper, considerations are presented on how a risk assessment for PPPs and terrestrial life-stages of amphibians could be conducted. It discusses available information concerning the toxicity of PPPs to terrestrial amphibians, and their potential exposure to PPPs in consideration of aspects of amphibian biology. The emphasis is on avoiding additional vertebrate testing as much as possible by using exposure-driven approaches and by making use of existing vertebrate toxicity data, where appropriate. Options for toxicity testing and risk assessment are presented in a flowchart as a tiered approach, progressing from a non-testing approach, to simple worst-case laboratory testing, to extended laboratory testing, to semi-field enclosure tests and ultimately to full-scale field testing and monitoring. Suggestions are made for triggers to progress to higher tiers. Also, mitigation options to reduce the potential for exposure of terrestrial life-stages of amphibians to PPPs, if a risk were identified, are discussed. Finally, remaining uncertainties and research needs are considered by proposing a way forward (road map) for generating additional information to inform terrestrial amphibian risk assessment. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Use of the intestinal parasite community of Sigmodon hispidus as a biomonitor in terrestrial systems

    International Nuclear Information System (INIS)

    Faulkner, B.C.; Lochmiller, R.L.

    1995-01-01

    The goal of this study was to assess the potential usefulness of parasite communities of small mammals as an endpoint for community level risk assessment in terrestrial ecosystems. A total of 350 wild cotton rats (Sigmodon hispidus) were collected from a Superfund site in southwestern Oklahoma between fall 1993 and fall 1995. Three contaminated study sites, representing common petrochemical disposal methods and all containing complex mixtures of contaminants, including arsenic, lead, fluoride, phenols, and hydrocarbons, were monitored seasonally. Animals were collected and gastrointestinal contents were examined grossly and microscopically for helminths and coccidial parasites. All parasites were identified to species and enumerated so that measurable alterations of the parasite community structure could be established. The authors also sampled possible intermediate host communities concurrently with Sigmodon collections. Structural characteristics of the parasite communities were compared between replicated toxic and reference study sites

  8. A pharm-ecological perspective of terrestrial and aquatic plant-herbivore interactions.

    Science.gov (United States)

    Forbey, Jennifer Sorensen; Dearing, M Denise; Gross, Elisabeth M; Orians, Colin M; Sotka, Erik E; Foley, William J

    2013-04-01

    We describe some recent themes in the nutritional and chemical ecology of herbivores and the importance of a broad pharmacological view of plant nutrients and chemical defenses that we integrate as "Pharm-ecology". The central role that dose, concentration, and response to plant components (nutrients and secondary metabolites) play in herbivore foraging behavior argues for broader application of approaches derived from pharmacology to both terrestrial and aquatic plant-herbivore systems. We describe how concepts of pharmacokinetics and pharmacodynamics are used to better understand the foraging phenotype of herbivores relative to nutrient and secondary metabolites in food. Implementing these concepts into the field remains a challenge, but new modeling approaches that emphasize tradeoffs and the properties of individual animals show promise. Throughout, we highlight similarities and differences between the historic and future applications of pharm-ecological concepts in understanding the ecology and evolution of terrestrial and aquatic interactions between herbivores and plants. We offer several pharm-ecology related questions and hypotheses that could strengthen our understanding of the nutritional and chemical factors that modulate foraging behavior of herbivores across terrestrial and aquatic systems.

  9. Plant succession and approaches to community restoration

    Science.gov (United States)

    Bruce A. Roundy

    2005-01-01

    The processes of vegetation change over time, or plant succession, are also the processes involved in plant community restoration. Restoration efforts attempt to use designed disturbance, seedbed preparation and sowing methods, and selection of adapted and compatible native plant materials to enhance ecological function. The large scale of wildfires and weed invasion...

  10. Ecological succession reveals potential signatures of marine-terrestrial transition in salt marsh fungal communities.

    Science.gov (United States)

    Dini-Andreote, Francisco; Pylro, Victor Satler; Baldrian, Petr; van Elsas, Jan Dirk; Salles, Joana Falcão

    2016-08-01

    Marine-to-terrestrial transition represents one of the most fundamental shifts in microbial life. Understanding the distribution and drivers of soil microbial communities across coastal ecosystems is critical given the roles of microbes in soil biogeochemistry and their multifaceted influence on landscape succession. Here, we studied the fungal community dynamics in a well-established salt marsh chronosequence that spans over a century of ecosystem development. We focussed on providing high-resolution assessments of community composition, diversity and ecophysiological shifts that yielded patterns of ecological succession through soil formation. Notably, despite containing 10- to 100-fold lower fungal internal transcribed spacer abundances, early-successional sites revealed fungal richnesses comparable to those of more mature soils. These newly formed sites also exhibited significant temporal variations in β-diversity that may be attributed to the highly dynamic nature of the system imposed by the tidal regime. The fungal community compositions and ecophysiological assignments changed substantially along the successional gradient, revealing a clear signature of ecological replacement and gradually transforming the environment from a marine into a terrestrial system. Moreover, distance-based linear modelling revealed soil physical structure and organic matter to be the best predictors of the shifts in fungal β-diversity along the chronosequence. Taken together, our study lays the basis for a better understanding of the spatiotemporally determined fungal community dynamics in salt marshes and highlights their ecophysiological traits and adaptation in an evolving ecosystem.

  11. Degradation of PVC/HC blends. II. Terrestrial plant growth test.

    Science.gov (United States)

    Pascu, Mihaela; Agafiţei, Gabriela-Elena; Profire, Lenuţa; Vasile, Cornelia

    2009-01-01

    The behavior at degradation by soil burial of some plasticized polyvinyl chloride (PVC) based blends with a variable content of hydrolyzed collagen (HC) has been followed. The modifications induced in the environment by the polymer systems (pH variation, physiologic state of the plants, assimilatory pigments) were studied. Using the growth test of the terrestrial plants, we followed the development of Triticum (wheat), Helianthus annus minimus (little sunflower), Pisum sativum (pea), and Vicia X hybrida hort, during a vegetation cycle. After the harvest, for each plant, the quantities of chlorophyll and carotenoidic pigments and of trace- and macroelements were determined. It was proved that, in the presence of polymer blends, the plants do not suffer morphological and physiological modifications, the products released in the culture soil being not toxic for the plants growth.

  12. Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America.

    Science.gov (United States)

    Mitchell, Jonathan S; Roopnarine, Peter D; Angielczyk, Kenneth D

    2012-11-13

    The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

  13. Soil ecosystem functioning under climate change: plant species and community effects

    Energy Technology Data Exchange (ETDEWEB)

    Kardol, Paul [ORNL; Cregger, Melissa [ORNL; Campany, Courtney E [ORNL; Classen, Aimee T [ORNL

    2010-01-01

    Feedbacks of terrestrial ecosystems to climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the microbial communities that feed on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and water availability. Specifically, we collected soils at the plot level (plant community soils), and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: 1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activities, and soil nematodes. Multiple climate change factors can interact to shape ecosystems, but in this case, those interactions were largely driven by changes in water availability. 2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning and this impact was not obvious when looking at plant community soils. Climate change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. In sum, these results indicate that accurate assessments of climate change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate change-induced shifts in plant community composition will likely modify or counteract the direct

  14. Modelling asymmetric growth in crowded plant communities

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2010-01-01

    A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size......-asymmetric growth part, where growth is assumed to be proportional to a power function of the size of the individual, and a term that reduces the relative growth rate as a decreasing function of the individual plant size and the competitive interactions from other plants in the neighbourhood....

  15. Mercury uptake and phytotoxicity in terrestrial plants grown naturally in the Gumuskoy (Kutahya) mining area, Turkey.

    Science.gov (United States)

    Sasmaz, Merve; Akgül, Bunyamin; Yıldırım, Derya; Sasmaz, Ahmet

    2016-01-01

    This study investigated mercury (Hg) uptake and transport from the soil to different plant parts by documenting the distribution and accumulation of Hg in the roots and shoots of 12 terrestrial plant species, all of which grow naturally in surface soils of the Gumuskoy Pb-Ag mining area. Plant samples and their associated soils were collected and analyzed for Hg content by ICP-MS. Mean Hg values in the soils, roots, and shoots of all plants were 6.914, 460, and 206 µg kg(-1), respectively and lower than 1. The mean enrichment factors for the roots (ECR) and shoots (ECS) of these plants were 0.06 and 0.09, respectively and lower than 1. These results show that the roots of the studied plants prevented Hg from reaching the aerial parts of the plants. The mean translocation factor (TLF) was 1.29 and higher than 1. The mean TLF values indicated that all 12 plant species had the ability to transfer Hg from the roots to the shoots but that transfer was more efficient in plants with higher ECR and ECS. Therefore, these plants could be useful for the biomonitoring of environmental pollution and for rehabilitating areas contaminated by Hg.

  16. Replacement of cowdung by fermentation of aquatic and terrestrial plants for use as fuel, fertilizer and biogas plant feed

    Energy Technology Data Exchange (ETDEWEB)

    Das, C. R.; Ghatnekar, S. D.

    1979-01-01

    With 85% of the entire Indian population living in villages and 98% of the household energy requirement of the rural population demanded for cooking, research was undertaken on the supply of biomass for those Indians who do not have cattle. This research was carried out on the fermentation of aquatic and terrestrial plants for use in biogas generation. The plants utilized for biogas generation are: water hyacinth, water lettuce, African payal, duck weed, water spinach, cattail ramban, ipil-ipil, morning glory, paragrass, purple nutsedge, and durva grass.

  17. Arsenic speciation in moso bamboo shoot - A terrestrial plant that contains organoarsenic species

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Rui [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084, P.R. China (China); Zhao Mengxia [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China); Wang Hui [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China); Taneike, Yasuhito [Shimadzu Co Ltd, Spectroscopy Business Unit Analytical Instruments Div, Nakagyo Ku, Kyoto, 6048511 (Japan); Zhang Xinrong [Department of Chemistry, Key laboratory for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua University, Beijing 100084 (China)]. E-mail: xrzhang@chem.tsinghua.edu.cn

    2006-12-01

    Arsenic is predominantly found as an inorganic species in most terrestrial plants. However, we found that a significant proportion of organic arsenic was present in moso bamboo (Phyllostachys pubescens Mazel) shoot in a market survey of arsenic species in edible terrestrial plants. Moso bamboo shoots from different producing areas in China were collected for analysis to confirm the ubiquity of methylated arsenic species. The total arsenic concentrations of bamboo shoots were determined by hydride generation coupled atomic fluorescence spectrometry (HG-AFS), ranging from 27.7 to 94.0 {mu}g/kg. Information about arsenic species was acquired from cold trap-hydride generation-atomic absorption spectrometry (CT-HG-AAS). Dimethylarsinic acid (DMA) was present in the amount of 13.9% to 44.9% of sum of the arsenic species in all these samples. Monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) were also detected in certain samples in the range of 4.2-16.5% and 11.8-18.4%, respectively. In addition, bamboo shoots collected in winter were found to have more total arsenic and organic arsenic than those collected in spring. To investigate the source of the organic arsenic in moso bamboo shoots, arsenic species in the rhizosphere soils of the plants were examined. The absence of organic arsenic in soils would suggest the possibility of formation of methylated arsenic in the plants. In addition, studies of arsenic speciation in the peel and core of winter bamboo shoots showed that all the cores contained organic arsenic while no organic arsenic was detected in the peels. The study provides useful information for better understanding of the distribution of arsenic species in terrestrial plants.

  18. Accumulation of radioactive cesium released from Fukushima Daiichi Nuclear Power Plant in terrestrial cyanobacteria Nostoc commune.

    Science.gov (United States)

    Sasaki, Hideaki; Shirato, Susumu; Tahara, Tomoya; Sato, Kenji; Takenaka, Hiroyuki

    2013-01-01

    The Fukushima Daiichi Nuclear Power Plant accident released large amounts of radioactive substances into the environment and contaminated the soil of Tohoku and Kanto districts in Japan. Removal of radioactive material from the environment is an urgent problem, and soil purification using plants is being considered. In this study, we investigated the ability of 12 seed plant species and a cyanobacterium to accumulate radioactive material. The plants did not accumulate radioactive material at high levels, but high accumulation was observed in the terrestrial cyanobacterium Nostoc commune. In Nihonmatsu City, Fukushima Prefecture, N. commune accumulated 415,000 Bq/kg dry weight (134)Cs and 607,000 Bq kg(-1) dry weight (137)Cs. The concentration of cesium in N. commune tended to be high in areas where soil radioactivity was high. A cultivation experiment confirmed that N. commune absorbed radioactive cesium from polluted soil. These data demonstrated that radiological absorption using N. commune might be suitable for decontaminating polluted soil.

  19. Woody plant encroachment of grasslands: a comparison of terrestrial and wetland settings.

    Science.gov (United States)

    Saintilan, Neil; Rogers, Kerrylee

    2015-02-01

    A global trend of woody plant encroachment of terrestrial grasslands is co-incident with woody plant encroachment of wetland in freshwater and saline intertidal settings. There are several arguments for considering tree encroachment of wetlands in the context of woody shrub encroachment of grassland biomes. In both cases, delimitation of woody shrubs at regional scales is set by temperature thresholds for poleward extent, and by aridity within temperature limits. Latitudinal expansion has been observed for terrestrial woody shrubs and mangroves, following recent warming, but most expansion and thickening has been due to the occupation of previously water-limited grassland/saltmarsh environments. Increases in atmospheric CO₂, may facilitate the recruitment of trees in terrestrial and wetland settings. Improved water relations, a mechanism that would predict higher soil moisture in grasslands and saltmarshes, and also an enhanced capacity to survive arid conditions, reinforces local mechanisms of change. The expansion of woody shrubs and mangroves provides a negative feedback on elevated atmospheric CO₂ by increasing carbon sequestration in grassland and saltmarsh, and is a significant carbon sink globally. These broad-scale vegetation shifts may represent a new stable state, reinforced by positive feedbacks between global change drivers and endogenic mechanisms of persistence in the landscape.

  20. Precise plant height monitoring and biomass estimation with Terrestrial Laser Scanning in paddy rice

    Directory of Open Access Journals (Sweden)

    N. Tilly

    2013-10-01

    Full Text Available Optimizing crop management is a major topic in the field of precision agriculture as the growing world population puts pressure on the efficiency of field production. Accordingly, methods to measure plant parameters with the needed precision and within-field resolution are required. Studies show that Terrestrial Laser Scanning (TLS is a suitable method to capture small objects like crop plants. In this contribution, the results of multi-temporal surveys on paddy rice fields with the TLS system Riegl LMS-Z420i are presented. Three campaigns were carried out during the key vegetative stage of rice plants in the growing period 2012 to monitor the plant height. The TLS-derived point clouds are interpolated to visualize plant height above ground as crop surface models (CSMs with a high resolution of 0.01 m. Spatio-temporal differences within the data of one campaign and between consecutive campaigns can be detected. The results were validated against manually measured plant heights with a high correlation (R2 = 0.71. Furthermore, the dependence of actual biomass from plant height was evaluated. To the present, no method for the non-destructive determination of biomass is found yet. Thus, plant parameters, like the height, have to be used for biomass estimations. The good correlation (R2 = 0.66 leads to the assumption that biomass can be estimated from plant height measurements. The results show that TLS can be considered as a very promising tool for precision agriculture.

  1. THE EUROPEAN POSITION OF DUTCH PLANT COMMUNITIES

    Directory of Open Access Journals (Sweden)

    J.A.M. JANSSEN

    2007-04-01

    Full Text Available In this paper it is analyzed for which plant communities (alliances the Netherlands has an international responsibility. Data has been brought together on the range and distribution of alliances in Europe, the area of plant communities in the Netherlands and surrounding countries and the occurrence of endemic associations in the Netherlands. The analysis resulted in a list of 34 out of 93 alliances in the Netherlands which are important from an international point of view.

  2. COMESEP: bridging the gap between the SEP, CME, and terrestrial effects scientific communities

    Science.gov (United States)

    Crosby, Norma; Veronig, Astrid; Rodriguez, Luciano; Vrsnak, Bojan; Vennerstrøm, Susanne; Malandraki, Olga; Dalla, Silvia; Srivastava, Nandita

    2016-04-01

    In the past there has been a tendency for the geomagnetic storm and solar energetic particle (SEP) communities to work in parallel rather than to apply a cross-disciplinary work approach specifically in regard to space weather forecasting. To provide more awareness on the existing links between these communities, as well as further bridge this gap, the three-year EU FP7 COMESEP (COronal Mass Ejections and Solar Energetic Particles: forecasting the space weather impact) project emphasized cross-collaboration between the SEP, coronal mass ejection, and terrestrial effects scientific communities. COMESEP went from basic solar-terrestrial physics research to space weather operations by developing, validating and implementing multi-purpose tools into an operational 24/7 alert service. Launched in November 2013, the COMESEP alert system provides space weather stakeholders geomagnetic storm alerts ("Event based" and "Next 24 hours") and SEP (proton) storm alerts (E > 10 MeV and E > 60 MeV) without human intervention based on the COMESEP definition of risk. COMESEP alerts and forecasts are freely available on the COMESEP alert website (http://www.comesep.eu/alert), as well as disseminated by e-mail to registered users. Acknowledgement: This work has received funding from the European Commission FP7 Project COMESEP (263252).

  3. Seed bank characteristics of Dutch plant communities

    NARCIS (Netherlands)

    Bekker, RM; Schaminee, JHJ; Bakker, JP; Thompson, K

    With the recent appearances of a new and well-documented classification of the Dutch plant communities (Schaminee et al 1995a,b; 1996) and a database on the seed longevity of plant species of North West Europe (Thompson ct al. 1997a) it was possible to investigate patterns of seed longevity in Dutch

  4. Quantitative Hydraulic Models Of Early Land Plants Provide Insight Into Middle Paleozoic Terrestrial Paleoenvironmental Conditions

    Science.gov (United States)

    Wilson, J. P.; Fischer, W. W.

    2010-12-01

    Fossil plants provide useful proxies of Earth’s climate because plants are closely connected, through physiology and morphology, to the environments in which they lived. Recent advances in quantitative hydraulic models of plant water transport provide new insight into the history of climate by allowing fossils to speak directly to environmental conditions based on preserved internal anatomy. We report results of a quantitative hydraulic model applied to one of the earliest terrestrial plants preserved in three dimensions, the ~396 million-year-old vascular plant Asteroxylon mackei. This model combines equations describing the rate of fluid flow through plant tissues with detailed observations of plant anatomy; this allows quantitative estimates of two critical aspects of plant function. First and foremost, results from these models quantify the supply of water to evaporative surfaces; second, results describe the ability of plant vascular systems to resist tensile damage from extreme environmental events, such as drought or frost. This approach permits quantitative comparisons of functional aspects of Asteroxylon with other extinct and extant plants, informs the quality of plant-based environmental proxies, and provides concrete data that can be input into climate models. Results indicate that despite their small size, water transport cells in Asteroxylon could supply a large volume of water to the plant's leaves--even greater than cells from some later-evolved seed plants. The smallest Asteroxylon tracheids have conductivities exceeding 0.015 m^2 / MPa * s, whereas Paleozoic conifer tracheids do not reach this threshold until they are three times wider. However, this increase in conductivity came at the cost of little to no adaptations for transport safety, placing the plant’s vegetative organs in jeopardy during drought events. Analysis of the thickness-to-span ratio of Asteroxylon’s tracheids suggests that environmental conditions of reduced relative

  5. Ozone sensitivity of plants in natural communities

    Energy Technology Data Exchange (ETDEWEB)

    Treshow, M; Stewart, D

    1973-07-01

    Field fumigation studies conducted in grassland, oak, aspen, and conifer, communities established the injury threshold of prevalent plant species to ozone. Several important species, including Bromus tectorum, Quercus gambelii, and Populus tremuloides, were injured by a single 2-hours exposure to 15 pphM ozone. Over half the perennial forbs and woody species studied were visibly injured at concentrations of 30 pphM ozone or less. It is postulated that lower concentrations at prolonged or repeated exposures to ozone may impair growth and affect community vigor and stability. Continued exposure of natural plant communities to ozone is expected to initiate major shifts in the plant composition of communities. 10 references, 4 figures, 1 table.

  6. Development of a short-term (<12 days), plant-based screening method to assess the bioavailability, bioconcentration, and phytotoxicity of Hexahydro-1,3,5- Trinitro-1,3,5-Tiazine (RDZ) to terrestrial plants

    Science.gov (United States)

    Linda Winfield; Steven D' Surney; John Rodgers

    2000-01-01

    Limited amounts of information have been published on the environmental impacts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to terrestrial plant communities. RDX is one of the two high-explosive compounds used by the U.S. military (Davis 1998) and classified as a priority pollutant by the U.S. Environmental Protection Agency (USEPA). Millions of acres of land on...

  7. Direct effect of acid rain on leaf chlorophyll content of terrestrial plants in China.

    Science.gov (United States)

    Du, Enzai; Dong, Dan; Zeng, Xuetong; Sun, Zhengzhong; Jiang, Xiaofei; de Vries, Wim

    2017-12-15

    Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial plants is lacking. Leaf chlorophyll content is an important indicator of direct foliage damage and strongly related to plant productivity. We synthesized data from published literature on experiments of simulated acid rain, by directly exposing plants to acid solutions with varying pH levels, to assess the direct effect of acid rain on leaf chlorophyll content across 67 terrestrial plants in China. Our results indicate that acid rain substantially reduces leaf chlorophyll content by 6.71% per pH unit across the recorded plant species. The direct reduction of leaf chlorophyll content due to acid rain exposure showed no significant difference across calcicole, ubiquist or calcifuge species, implying that soil acidity preference does not influence the sensitivity to leaf injury by acid rain. On average, the direct effects of acid rain on leaf chlorophyll on trees, shrubs and herbs were comparable. The effects, however varied across functional groups and economic use types. Specifically, leaf chlorophyll content of deciduous species was more sensitive to acid rain in comparison to evergreen species. Moreover, vegetables and fruit trees were more sensitive to acid rain than other economically used plants. Our findings imply a potential production reduction and economic loss due to the direct foliage damage by acid rain. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

    Science.gov (United States)

    Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

    2017-12-19

    Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

  9. Microbial Community Response to Terrestrially Derived Dissolved Organic Matter in the Coastal Arctic

    Directory of Open Access Journals (Sweden)

    Rachel E. Sipler

    2017-06-01

    Full Text Available Warming at nearly twice the global rate, higher than average air temperatures are the new ‘normal’ for Arctic ecosystems. This rise in temperature has triggered hydrological and geochemical changes that increasingly release carbon-rich water into the coastal ocean via increased riverine discharge, coastal erosion, and the thawing of the semi-permanent permafrost ubiquitous in the region. To determine the biogeochemical impacts of terrestrially derived dissolved organic matter (tDOM on marine ecosystems we compared the nutrient stocks and bacterial communities present under ice-covered and ice-free conditions, assessed the lability of Arctic tDOM to coastal microbial communities from the Chukchi Sea, and identified bacterial taxa that respond to rapid increases in tDOM. Once thought to be predominantly refractory, we found that ∼7% of dissolved organic carbon and ∼38% of dissolved organic nitrogen from tDOM was bioavailable to receiving marine microbial communities on short 4 – 6 day time scales. The addition of tDOM shifted bacterial community structure toward more copiotrophic taxa and away from more oligotrophic taxa. Although no single order was found to respond universally (positively or negatively to the tDOM addition, this study identified 20 indicator species as possible sentinels for increased tDOM. These data suggest the true ecological impact of tDOM will be widespread across many bacterial taxa and that shifts in coastal microbial community composition should be anticipated.

  10. Draft Genome Sequence of the Plant Growth-Promoting Cupriavidus gilardii Strain JZ4 Isolated from the Desert Plant Tribulus terrestris

    KAUST Repository

    Lafi, Feras Fawzi

    2016-07-28

    We isolated the plant endophytic bacterium Cupriavidus gilardii strain JZ4 from the roots of the desert plant Tribulus terrestris, collected from the Jizan region, Saudi Arabia. We report here the draft genome sequence of JZ4, together with several enzymes related to plant growth-promoting activity, environmental adaption, and antifungal activity.

  11. Draft Genome Sequence of the Plant Growth-Promoting Cupriavidus gilardii Strain JZ4 Isolated from the Desert Plant Tribulus terrestris

    KAUST Repository

    Lafi, Feras Fawzi; Bokhari, Ameerah; Alam, Intikhab; Bajic, Vladimir B.; Hirt, Heribert; Saad, Maged

    2016-01-01

    We isolated the plant endophytic bacterium Cupriavidus gilardii strain JZ4 from the roots of the desert plant Tribulus terrestris, collected from the Jizan region, Saudi Arabia. We report here the draft genome sequence of JZ4, together with several enzymes related to plant growth-promoting activity, environmental adaption, and antifungal activity.

  12. Insights into deep-time terrestrial carbon cycle processes from modern plant isotope ecology

    Science.gov (United States)

    Sheldon, N. D.; Smith, S. Y.

    2012-12-01

    While the terrestrial biosphere and soils contain much of the readily exchangeable carbon on Earth, how those reservoirs function on long time scales and at times of higher atmospheric CO2 and higher temperatures is poorly understood, which limits our ability to make accurate future predictions of their response to anthropogenic change. Recent data compilation efforts have outlined the response of plant carbon isotope compositions to a variety of environmental factors including precipitation amount and timing, elevation, and latitude. The compilations involve numerous types of plants, typically only found at a limited number of climatic conditions. Here, we expand on those efforts by examining the isotopic response of specific plant groups found both globally and across environmental gradients including: 1) ginkgo, 2) conifers, and 3) C4 grasses. Ginkgo is presently widely distributed as a cultivated plant and the ginkgoalean fossil record spans from the Permian to the present, making it an ideal model organism to understand climatic influence on carbon cycling both in modern and ancient settings. Ginkgo leaves have been obtained from a range of precipitation conditions (400-2200 mm yr-1), including dense sampling from individuals and populations in both Mediterranean and temperate climate areas and samples of different organs and developmental stages. Ginkgo carbon isotope results plot on the global C3 plant array, are consistent among trees at single sites, among plant organs, and among development stages, making ginkgo a robust recorder of both climatic conditions and atmospheric δ13C. In contrast, a climate-carbon isotope transect in Arizona highlights that conifers (specifically, pine and juniper) record large variability between organs and have a very different δ13C slope as a function of climate than the global C3 plant array, while C4 plants have a slope with the opposite sign as a function of climate. This has a number of implications for paleo

  13. The Limits of Acclimation of land plants in a Terrestrial Ecosystems Model

    Science.gov (United States)

    Kothavala, Zavareh

    2014-05-01

    In this study, we examine the role of the terrestrial carbon cycle and the ability of different plant types to acclimate to a changing climate at the centennial scale using a global ecosystems model with updated biogeochemical processes related to moisture, carbon, and nitrogen. Elevated level of atmospheric carbon dioxide (CO2) increases CO2 fertilization, resulting in more CO2 uptake by vegetation, whereas the concomitant warming increases autotrophic and heterotrophic respiration, releasing CO2 to the atmosphere. Additionally, warming will enhance photosynthesis if current temperatures are below the optimal temperature for plant growth, while it will reduce photosynthesis if current temperatures are above the optimal temperature for plant growth. We present a series of ensemble simulations to evaluate the ability of plants to acclimate to changing conditions over the last century and how this affects the terrestrial carbon sink. A set of experiments related to (a) the varying relationship between CO2 fertilization and the half saturation constant, (b) the factors related to gross primary productivity and maintenance respiration, and (c) the variables related to heterotrophic respiration, were conducted with thirteen plant functional types. The experiments were performed using the Terrestrial Ecosystem Model (TEM) with a present-day vegetation distribution without the effects of natural or human disturbance, and a closed Nitrogen cycle, at a half-degree resolution over the globe. The experiment design consisted of eight scenarios that are consistent with past and future ecosystem conditions, presented in other scientific studies. The significance of model trends related to runoff, soil moisture, soil carbon, Net Primary Productivity (NPP), crop yield, and Net Ecosystem Productivity (NEP) for different seasons, as well as surface temperature, precipitation, vapor pressure, and photosynthetically active radiation are analyzed for various ecosystems at the global

  14. PLANT COMMUNITIES OF ALBANIA - A PRELIMINARY OVERVIEW

    Directory of Open Access Journals (Sweden)

    J. DRING

    2002-04-01

    Full Text Available The phytosociological analysis of Albania was initiated by F. Markgraf in the 30ies, but still remains incomplete. This is a preliminary list of the plant communities resulting from the literature and from field research carried out during the last years and may represent a first contribution for further research. Many communities are described only by dominant species, other are quoted as nomina nuda. Some further syntaxa. probably present in the study area, are added.

  15. Native plant community response to alien plant invasion and removal

    Directory of Open Access Journals (Sweden)

    Jara ANDREU

    2011-01-01

    Full Text Available Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

  16. Dual role of lignin in plant litter decomposition in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Ballaré, Carlos L

    2010-03-09

    Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems.

  17. Toxicological benchmarks for screening potential contaminants of concern for effects on terrestrial plants

    International Nuclear Information System (INIS)

    Suter, G.W. II; Will, M.E.; Evans, C.

    1993-09-01

    One of the initial stages in ecological risk assessment for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as ''contaminants of potential concern.'' This process is termed ''contaminant screening.'' It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to plants. This report presents a standard method for deriving benchmarks for this purpose (phytotoxicity benchmarks), a set of data concerning effects of chemicals in soil or soil solution on plants, and a set of phytotoxicity benchmarks for 34 chemicals potentially associated with US Department of Energy (DOE) sites. Chemicals that are found in soil at concentrations exceeding both the phytotoxicity benchmark and the background concentration for the soil type should be considered contaminants of potential concern. The purpose of this report is to present plant toxicity data and discuss their utility as benchmarks for determining the hazard to terrestrial plants caused by contaminants in soil. Benchmarks are provided for soils and solutions

  18. Toxicological benchmarks for screening potential contaminants of concern for effects on terrestrial plants. Environmental Restoration Program

    Energy Technology Data Exchange (ETDEWEB)

    Suter, G.W. II; Will, M.E.; Evans, C.

    1993-09-01

    One of the initial stages in ecological risk assessment for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as ``contaminants of potential concern.`` This process is termed ``contaminant screening.`` It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to plants. This report presents a standard method for deriving benchmarks for this purpose (phytotoxicity benchmarks), a set of data concerning effects of chemicals in soil or soil solution on plants, and a set of phytotoxicity benchmarks for 34 chemicals potentially associated with US Department of Energy (DOE) sites. Chemicals that are found in soil at concentrations exceeding both the phytotoxicity benchmark and the background concentration for the soil type should be considered contaminants of potential concern. The purpose of this report is to present plant toxicity data and discuss their utility as benchmarks for determining the hazard to terrestrial plants caused by contaminants in soil. Benchmarks are provided for soils and solutions.

  19. Nuclear power plant and the host community

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, G

    1978-10-27

    A councillor from a small Swedish community (Kaevlinge) in the vicinity of the Barsebaeck nuclear power plant describes the effects which the plant has had on neighbouring communities. The effect on the labour market has been small at Kaevlinge, both during routine operation and construction phases. This is however, a fairly densely populated area with a population of half a million in a radius of 30 km. The situation is different at Oskarshamn or Oesthammar. Neither has there been any special economic benefit, due to Swedish taxation laws. There has been little local anxiety due to the proximity of the nuclear power plant. Certain local planning problems have been caused by restricted zones and power cables. Cooperation between the local authorities and the utility has been good.

  20. Effects of ionizing radiation on terrestrial plants and animals: A workshop report

    International Nuclear Information System (INIS)

    Barnthouse, L.W.

    1995-12-01

    The US Department of Energy (DOE) Air, Water, and Radiation Division (EH-412) is preparing to issue protective radiological standards for aquatic and terrestrial organisms. To support this effort, DOE sponsored a workshop to evaluate the adequacy of current approaches to radiological protection. Workshop participants reviewed and discussed a 1992 International Atomic Energy Agency (IAEA) report on radiological protection of biota for its adequacy and completeness in answering the following questions: can DOE use these data and conclusions for promulgating radiological standards for the protection of terrestrial organisms; are the conclusions given in this report still valid or have they been superseded by more recent data? The consensus of the workshop participants was that the dose limits for animals and plants recommended by the IAEA are adequately supported by the available scientific information. Participants agreed, however, that better guidance on application of those dose limits is needed. Participants further agreed with the IAEA that dose limits deigned to protect humans generally protect biota as well, except when (1) human access is restricted without restricting access by biota, (2) unique exposure pathways exist, (3) rare or endangered species are present, or (4) other stresses are significant. To deal with these exceptions, site-specific exposures should be considered in developing secondary standards

  1. Effects of ionizing radiation on terrestrial plants and animals: A workshop report

    Energy Technology Data Exchange (ETDEWEB)

    Barnthouse, L.W.

    1995-12-01

    The US Department of Energy (DOE) Air, Water, and Radiation Division (EH-412) is preparing to issue protective radiological standards for aquatic and terrestrial organisms. To support this effort, DOE sponsored a workshop to evaluate the adequacy of current approaches to radiological protection. Workshop participants reviewed and discussed a 1992 International Atomic Energy Agency (IAEA) report on radiological protection of biota for its adequacy and completeness in answering the following questions: can DOE use these data and conclusions for promulgating radiological standards for the protection of terrestrial organisms; are the conclusions given in this report still valid or have they been superseded by more recent data? The consensus of the workshop participants was that the dose limits for animals and plants recommended by the IAEA are adequately supported by the available scientific information. Participants agreed, however, that better guidance on application of those dose limits is needed. Participants further agreed with the IAEA that dose limits deigned to protect humans generally protect biota as well, except when (1) human access is restricted without restricting access by biota, (2) unique exposure pathways exist, (3) rare or endangered species are present, or (4) other stresses are significant. To deal with these exceptions, site-specific exposures should be considered in developing secondary standards.

  2. The incidence of Pyrenochaeta terrestris in root of different plant species in Serbia

    Directory of Open Access Journals (Sweden)

    Lević Jelena T.

    2013-01-01

    Full Text Available Root samples of cereals (oats, wheat, barley, maize and sorghum, vegetables (garlic, onion, pepper, cucumber, pumpkin, carrot and tomato, industrial plant (soya bean and weeds (Johnson grass, barnyard grass and green bristle-grass collected in different agroecological conditions in Serbia were analysed for the presence of Pyrenochaeta terrestris. The fungus was found in 42 out of 51 samples (82.4%, while the incidence varied from 2.5 to 72.5%. The highest incidence was detected in cereals (average 30.3%, and then in weeds of the Poaceae family (average 14.2%. Considering single species, maize (up to 72.5% in root and Johnson grass (up to 37.5% were mostly attacked by this fungus. The lowest incidence of the fungus was determined in vegetable crops (average 6.7%. Red to reddish discoloration of root was correlated with the incidence of the fungus. Obtained data indicate that P. terrestris is widespread in Serbia and conditions for its development are favourable. [Projekat Ministarstva nauke Republike Srbije, br. TR-31023

  3. BIO-MONITORING FOR URANIUM USING STREAM-SIDE TERRESTRIAL PLANTS AND MACROPHYTES

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, E.; Duff, M.; Hicks, T.; Coughlin, D.; Hicks, R.; Dixon, E.

    2012-01-12

    This study evaluated the abilities of various plant species to act as bio-monitors for environmental uranium (U) contamination. Vegetation and soil samples were collected from a U processing facility. The water-way fed from facility storm and processing effluents was the focal sample site as it represented a primary U transport mechanism. Soils and sediments from areas exposed to contamination possessed U concentrations that averaged 630 mg U kg{sup -1}. Aquatic mosses proved to be exceptional accumulators of U with dry weight (dw) concentrations measuring as high as 12500 mg U kg{sup -1} (approximately 1% of the dw mass was attributable to U). The macrophytes (Phragmites communis, Scripus fontinalis and Sagittaria latifolia) were also effective accumulators of U. In general, plant roots possessed higher concentrations of U than associated upper portions of plants. For terrestrial plants, the roots of Impatiens capensis had the highest observed levels of U accumulation (1030 mg kg{sup -1}), followed by the roots of Cyperus esculentus and Solidago speciosa. The concentration ratio (CR) characterized dry weight (dw) vegetative U levels relative to that in associated dw soil. The plant species that accumulated U at levels in excess of that found in the soil were: P. communis root (CR, 17.4), I. capensis root (CR, 3.1) and S. fontinalis whole plant (CR, 1.4). Seven of the highest ten CR values were found in the roots. Correlations with concentrations of other metals with U were performed, which revealed that U concentrations in the plant were strongly correlated with nickel (Ni) concentrations (correlation: 0.992; r-squared: 0.984). Uranium in plant tissue was also strongly correlated with strontium (Sr) (correlation: 0.948; r-squared: 0.899). Strontium is chemically and physically similar to calcium (Ca) and magnesium (Mg), which were also positively-correlated with U. The correlation with U and these plant nutrient minerals, including iron (Fe), suggests that active

  4. Uptake and fate of phenol, aniline and quinoline in terrestrial plants

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Bean, R.M.; Fellows, R.J.

    1987-06-01

    The bioavailability and chemical fate of xenobiotics in terrestrial plants can influence the impact of fossil fuel development on the human food chain. To determine the relative behavior of organic residues representing a range of chemical classes, we compared the rates of root absorption, tissue distribution and chemical fate of phenol, aniline and quinoline in soybean plants. Root absorption rates for these compounds were 180, 13 and 30 μg/g (fresh weight) root/day, respectively. Following uptake, aniline was concentrated in the root, while phenol and quinoline were evenly distributed in roots and leaves. After accumulation, phenol was readily decomposed, and its carbon was respired. While aniline was susceptible to oxidative decomposition, it persisted in leaves and roots; 25% of the soluble activity represented aniline, and a significant fraction was bound or conjugated to cell constitutents. Quinoline persisted both in the parent form and as metabolic products. However, in leaves, additional compounds were found that were chemically similar to quinoline; these were not found in unexposed plants. A substantial fraction of the quinoline accumulated by leaves was emitted to the atmosphere by volatilization. 12 refs., 5 tabs., 2 figs

  5. Evaluating the effects of herbicide drift on nontarget terrestrial plants: A case study with mesotrione.

    Science.gov (United States)

    Brain, Richard A; Perine, Jeff; Cooke, Catriona; Ellis, Clare Butler; Harrington, Paul; Lane, Andrew; O'Sullivan, Christine; Ledson, Mark

    2017-09-01

    Nature of exposure is a fundamental driver in nontarget terrestrial plant risk assessment for pesticides; consequently a novel study was designed to generate field-based drift exposure and evaluate corresponding biological effects of the herbicide mesotrione. The approach used a combination of US guideline drift reduction technology and vegetative vigor approaches. In each of 3 independent replicate spray application trials, 10 pots each of lettuce and tomato were placed at distances of 10, 20, 30, 40, and 50 ft (∼3, 6, 9, 12, and 15 m) from the downwind edge of the spray boom. Each application was conducted using a commercial 60-ft (18-m) boom sprayer fitted with TeeJet ® Technologies TTI110025 nozzles, with a nominal application rate of 0.2 lb a.i./A (224 g a.i./ha). The environmental conditions required by the protocol (air temperature 10-30 °C and wind perpendicular to the swath (±30°) blowing toward the plants at a mean wind speed of ≥10 mph [≥4.5 m/s] measured at 2.0 m above the ground) were met for each application. Following exposure, plants were transferred to a greenhouse for the 21-d vegetative vigor phase of the study. Symptoms of phytotoxicity and plant height were assessed at 7, 14, and 21 d after treatment. On completion of the 21-d after treatment assessment, all plants were harvested and dried in an oven to determine shoot dry weight. The biological data indicated that no statistically significant effects were observed at a distance of 30 ft (∼9 m) from mesotrione drift at wind speeds of ≥10 mph (10.9-12.4 mph); this endpoint (30 ft) is defined as the no observed effects distance (NOED). Environ Toxicol Chem 2017;36:2465-2475. © 2017 SETAC. © 2017 SETAC.

  6. Microbial Communities of Terrestrial Springs in Extensional Settings of the Western U.S.A.

    Science.gov (United States)

    Takacs-Vesbach, C.; Hall, J.; Crossey, L. J.; Karlstrom, K. E.; Fischer, T.; Cron, B.

    2008-12-01

    Gas and water chemistry from hot springs, gas vents, travertine-bearing cool springs, and high-pCO2 groundwaters of the western U.S. indicate a regionally extensive flux of deeply sourced volatiles through spring vents. We use the term "continental smokers" to emphasize and test analogs to mid-ocean vent systems, and are currently concentrating on vents in the Rocky Mountain/Colorado Plateau region as part of the Colorado Rockies and Experiment and Seismic transects (CREST). Measurable mantle-derived helium components (3He/4He = 0.10 to 2.1 RA) occur in nearly all springs in Colorado and New Mexico suggesting direct fast fluid pathways from the mantle to the surface hydrologic system. Important components of the CO2 are also derived from the mantle. We surveyed the geochemistry and microbial diversity of more than forty deeply sourced terrestrial springs that ranged in temperatures from 9° to 70°C. We hypothesize that degassing in continental extensional settings supports microbial assemblages that are analogous to chemolithotrophic communities at mid-ocean ridges and continental volcanic hydrothermal systems. Geochemical characteristics of the fluids and gases structure and sustain distinctive geomicrobiological communities as indicated by the widespread presence of archaea and thermophilic organisms in cool as well as hot springs.

  7. Islands in a Sea of Mud: Insights From Terrestrial Island Theory for Community Assembly on Insular Marine Substrata.

    Science.gov (United States)

    Meyer, K S

    Most marine hard-bottom habitats are isolated, separated from other similar habitats by sand or mud flats, and can be considered analogous to terrestrial islands. The extensive scientific literature on terrestrial islands provides a theoretical framework for the analysis of isolated marine habitats. More individuals and higher species richness occur on larger marine substrata, a pattern that resembles terrestrial islands. However, while larger terrestrial islands have greater habitat diversity and productivity, the higher species richness on larger marine hard substrata can be explained by simple surface area and hydrodynamic phenomena: larger substrata extend further into the benthic boundary, exposing fauna to faster current and higher food supply. Marine island-like communities are also influenced by their distance to similar habitats, but investigations into the reproductive biology and dispersal ability of individual species are required for a more complete understanding of population connectivity. On terrestrial islands, nonrandom co-occurrence patterns have been attributed to interspecific competition, but while nonrandom co-occurrence patterns have been found for marine fauna, different mechanisms are responsible, including epibiontism. Major knowledge gaps for community assembly in isolated marine habitats include the degree of connectivity between isolated habitats, mechanisms of succession, and the extent of competition on hard substrata, particularly in the deep sea. Anthropogenic hard substrata of known age can be used opportunistically as "natural" laboratories to begin answering these questions. © 2017 Elsevier Ltd. All rights reserved.

  8. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments

    Science.gov (United States)

    Xu, Liang; Zhou, Zhen-Feng

    2017-03-01

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants.

  9. Radioactive characterization of the terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plant

    International Nuclear Information System (INIS)

    Sibello Hernandez, R.Y.; Alonso Hernandez, C.M.; Diaz Asencio, M.; Cartas Aguila, H. A.

    1999-01-01

    In this work the results are exposed obtained by the Laboratory of Environmental Surveillance in the radioactive characterization of the existent terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plants in Cienfuegos, Cuba, starting from 1986 and up to 1993

  10. Plant interactions with multiple insect herbivores: from community to genes

    NARCIS (Netherlands)

    Stam, J.M.; Kroes, A.; Li, Y.; Gols, R.; Loon, van J.J.A.; Poelman, E.H.; Dicke, M.

    2014-01-01

    Every plant is a member of a complex insect community that consists of tens to hundreds of species that belong to different trophic levels. The dynamics of this community are critically influenced by the plant, which mediates interactions between community members that can occur on the plant

  11. Non-linear direct effects of acid rain on leaf photosynthetic rate of terrestrial plants.

    Science.gov (United States)

    Dong, Dan; Du, Enzai; Sun, Zhengzhong; Zeng, Xuetong; de Vries, Wim

    2017-12-01

    Anthropogenic emissions of acid precursors have enhanced global occurrence of acid rain, especially in East Asia. Acid rain directly suppresses leaf function by eroding surface waxes and cuticle and leaching base cations from mesophyll cells, while the simultaneous foliar uptake of nitrates in rainwater may directly benefit leaf photosynthesis and plant growth, suggesting a non-linear direct effect of acid rain. By synthesizing data from literature on acid rain exposure experiments, we assessed the direct effects of acid rain on leaf photosynthesis across 49 terrestrial plants in China. Our results show a non-linear direct effect of acid rain on leaf photosynthetic rate, including a neutral to positive effect above pH 5.0 and a negative effect below that pH level. The acid rain sensitivity of leaf photosynthesis showed no significant difference between herbs and woody species below pH 5.0, but the impacts above that pH level were strongly different, resulting in a significant increase in leaf photosynthetic rate of woody species and an insignificant effect on herbs. Our analysis also indicates a positive effect of the molar ratio of nitric versus sulfuric acid in the acid solution on leaf photosynthetic rate. These findings imply that rainwater acidity and the composition of acids both affect the response of leaf photosynthesis and therefore result in a non-linear direct effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A compact, inherently safe liquid metal reactor plant concept for terrestrial defense power applications

    International Nuclear Information System (INIS)

    Magee, P.M.; Dubberley, A.E.; Lutz, D.E.; Palmer, R.S.

    1987-01-01

    A compact, inherently safe, liquid metal reactor concept based on the GE PRISM innovative LMR design has been developed for terrestrial defense power applications in the 2-50 MWe range. The concept uses a small, sodium-cooled, U-5%Zr metal fueled reactor contained within two redundant steel vessels. The core is designed to operate at a low power density and temperature (925 F) and can operate 30 years without refueling. One two primary coolant loops, depending upon the plant size, transport heat from the core to sodium-to-air, double-wall heat exchangers. Power is produced by a gas turbine operated in a closed ''bottoming'' cycle that employs intercoolers between the compressor stages and a recuperator. Inherent safety is provided by passive means only; operator action is not required to ensure plant safety even for events normally considered Beyond Design Basis Accidents. In addition to normal shutdown heat removal via the sodium-to-air heat exchangers, the design utilizes an inherently passive radiant vessel auxiliary cooling system similar to that designed for PRISM. The use of an air cycle gas turbine eliminates the cost and complexity of the sodium-water reactor pressure relief system required for a steam cycle sodium-cooled reactor

  13. Three-Dimensional Reconstruction of the Virtual Plant Branching Structure Based on Terrestrial LIDAR Technologies and L-System

    Science.gov (United States)

    Gong, Y.; Yang, Y.; Yang, X.

    2018-04-01

    For the purpose of extracting productions of some specific branching plants effectively and realizing its 3D reconstruction, Terrestrial LiDAR data was used as extraction source of production, and a 3D reconstruction method based on Terrestrial LiDAR technologies combined with the L-system was proposed in this article. The topology structure of the plant architectures was extracted using the point cloud data of the target plant with space level segmentation mechanism. Subsequently, L-system productions were obtained and the structural parameters and production rules of branches, which fit the given plant, was generated. A three-dimensional simulation model of target plant was established combined with computer visualization algorithm finally. The results suggest that the method can effectively extract a given branching plant topology and describes its production, realizing the extraction of topology structure by the computer algorithm for given branching plant and also simplifying the extraction of branching plant productions which would be complex and time-consuming by L-system. It improves the degree of automation in the L-system extraction of productions of specific branching plants, providing a new way for the extraction of branching plant production rules.

  14. THREE-DIMENSIONAL RECONSTRUCTION OF THE VIRTUAL PLANT BRANCHING STRUCTURE BASED ON TERRESTRIAL LIDAR TECHNOLOGIES AND L-SYSTEM

    Directory of Open Access Journals (Sweden)

    Y. Gong

    2018-04-01

    Full Text Available For the purpose of extracting productions of some specific branching plants effectively and realizing its 3D reconstruction, Terrestrial LiDAR data was used as extraction source of production, and a 3D reconstruction method based on Terrestrial LiDAR technologies combined with the L-system was proposed in this article. The topology structure of the plant architectures was extracted using the point cloud data of the target plant with space level segmentation mechanism. Subsequently, L-system productions were obtained and the structural parameters and production rules of branches, which fit the given plant, was generated. A three-dimensional simulation model of target plant was established combined with computer visualization algorithm finally. The results suggest that the method can effectively extract a given branching plant topology and describes its production, realizing the extraction of topology structure by the computer algorithm for given branching plant and also simplifying the extraction of branching plant productions which would be complex and time-consuming by L-system. It improves the degree of automation in the L-system extraction of productions of specific branching plants, providing a new way for the extraction of branching plant production rules.

  15. Actual versus predicted impacts of three ethanol plants on aquatic and terrestrial resources

    International Nuclear Information System (INIS)

    Eddlemon, G.K.; Webb, J.W.; Hunsaker, D.B. Jr.; Miller, R.L.

    1993-01-01

    To help reduce US dependence on imported petroleum, Congress passed the Energy Security Act of 1980 (public Law 96-294). This legislation authorized the US Department of Energy (DOE) to promote expansion of the fuel alcohol industry through, among other measures, its Alcohol Fuels Loan Guarantee Program. Under this program, selected proposals for the conversion of plant biomass into fuel-grade ethanol would be granted loan guarantees. of 57 applications submitted for loan guarantees to build and operate ethanol fuel projects under this program, 11 were considered by DOE to have the greatest potential for satisfying DOE's requirements and goals. In accordance with the National Environmental Policy Act (NEPA), DOE evaluated the potential impacts of proceeding with the Loan Guarantee Program in a programmatic environmental assessment (DOE 1981) that resulted in a finding of no significant impact (FANCY) (47 Federal Register 34, p. 7483). The following year, DOE conducted site-specific environmental assessments (EAs) for 10 of the proposed projects. These F-As predicted no significant environmental impacts from these projects. Eventually, three ethanol fuel projects received loan guarantees and were actually built: the Tennol Energy Company (Tennol; DOE 1982a) facility near Jasper in southeastern Tennessee; the Agrifuels Refining Corporation (Agrifuels; DOE 1985) facility near New Liberia in southern Louisiana; and the New Energy Company of Indiana (NECI; DOE 1982b) facility in South Bend, Indiana. As part of a larger retrospective examination of a wide range of environmental effects of ethanol fuel plants, we compared the actual effects of the three completed plants on aquatic and terrestrial resources with the effects predicted in the NEPA EAs several years earlier. A secondary purpose was to determine: Why were there differences, if any, between actual effects and predictions? How can assessments be improved and impacts reduced?

  16. Soil Microbial Communities and Gas Dynamics Contribute to Arbuscular Mycorrhizal Nitrogen Uptake and Transfer to Plants

    Science.gov (United States)

    Hestrin, R.; Harrison, M. J.; Lehmann, J.

    2016-12-01

    Arbuscular mycorrhizal fungi (AMF) associate with most terrestrial plants and influence ecosystem ecology and biogeochemistry. There is evidence that AMF play a role in soil nitrogen cycling, in part by taking up nitrogen and transferring it to plants. However, many aspects of this process are poorly understood, including the factors that control fungal access to nitrogen stored in soil organic matter. In this study, we used stable isotopes and root exclusion to track nitrogen movement from organic matter into AMF and host plants. AMF significantly increased total plant biomass and nitrogen content, but both AMF and other soil microbes seemed to compete with plants for nitrogen. Surprisingly, gaseous nitrogen species also contributed significantly to plant nitrogen content under alkaline soil conditions. Our current experiments investigate whether free-living microbial communities that have evolved under a soil nitrogen gradient influence AMF access to soil organic nitrogen and subsequent nitrogen transfer to plants. This research links interactions between plants, mycorrhizal symbionts, and free-living microbes with terrestrial carbon and nitrogen dynamics.

  17. Influence of ice and snow covers on the UV exposure of terrestrial microbial communities: dosimetric studies.

    Science.gov (United States)

    Cockell, Charles S; Rettberg, Petra; Horneck, Gerda; Wynn-Williams, David D; Scherer, Kerstin; Gugg-Helminger, Anton

    2002-08-01

    Bacillus subtilis spore biological dosimeters and electronic dosimeters were used to investigate the exposure of terrestrial microbial communities in micro-habitats covered by snow and ice in Antarctica. The melting of snow covers of between 5- and 15-cm thickness, depending on age and heterogeneity, could increase B. subtilis spore inactivation by up to an order of magnitude, a relative increase twice that caused by a 50% ozone depletion. Within the snow-pack at depths of less than approximately 3 cm snow algae could receive two to three times the DNA-weighted irradiance they would receive on bare ground. At the edge of the snow-pack, warming of low albedo soils resulted in the formation of overhangs that provided transient UV protection to thawed and growing microbial communities on the soils underneath. In shallow aquatic habitats, thin layers of heterogeneous ice of a few millimetres thickness were found to reduce DNA-weighted irradiances by up to 55% compared to full-sky values with equivalent DNA-weighted diffuse attenuation coefficients (K(DNA)) of >200 m(-1). A 2-mm snow-encrusted ice cover on a pond was equivalent to 10 cm of ice on a perennially ice covered lake. Ice covers also had the effect of stabilizing the UV exposure, which was often subject to rapid variations of up to 33% of the mean value caused by wind-rippling of the water surface. These data show that changing ice and snow covers cause relative changes in microbial UV exposure at least as great as those caused by changing ozone column abundance. Copyright 2002 Elsevier Science B.V.

  18. Interactions among predators and the cascading effects of vertebrate insectivores on arthropod communities and plants.

    Science.gov (United States)

    Mooney, Kailen A; Gruner, Daniel S; Barber, Nicholas A; Van Bael, Sunshine A; Philpott, Stacy M; Greenberg, Russell

    2010-04-20

    Theory on trophic interactions predicts that predators increase plant biomass by feeding on herbivores, an indirect interaction called a trophic cascade. Theory also predicts that predators feeding on predators, or intraguild predation, will weaken trophic cascades. Although past syntheses have confirmed cascading effects of terrestrial arthropod predators, we lack a comprehensive analysis for vertebrate insectivores-which by virtue of their body size and feeding habits are often top predators in these systems-and of how intraguild predation mediates trophic cascade strength. We report here on a meta-analysis of 113 experiments documenting the effects of insectivorous birds, bats, or lizards on predaceous arthropods, herbivorous arthropods, and plants. Although vertebrate insectivores fed as intraguild predators, strongly reducing predaceous arthropods (38%), they nevertheless suppressed herbivores (39%), indirectly reduced plant damage (40%), and increased plant biomass (14%). Furthermore, effects of vertebrate insectivores on predatory and herbivorous arthropods were positively correlated. Effects were strongest on arthropods and plants in communities with abundant predaceous arthropods and strong intraguild predation, but weak in communities depauperate in arthropod predators and intraguild predation. The naturally occurring ratio of arthropod predators relative to herbivores varied tremendously among the studied communities, and the skew to predators increased with site primary productivity and in trees relative to shrubs. Although intraguild predation among arthropod predators has been shown to weaken herbivore suppression, we find this paradigm does not extend to vertebrate insectivores in these communities. Instead, vertebrate intraguild preda-tion is associated with strengthened trophic cascades, and insectivores function as dominant predators in terrestrial plant-arthropod communities.

  19. Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

    Science.gov (United States)

    Metcalfe, D. B.; Fisher, R. A.; Wardle, D. A.

    2011-08-01

    Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon (C) balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil - such as soil microbes, plant roots and their mycorrhizal symbionts - each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge. Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future climate, many plant communities may shift towards dominance by fast growing plants which

  20. Global assessment of the effects of terrestrial acidification on plant species richness

    International Nuclear Information System (INIS)

    Azevedo, Ligia B.; Zelm, Rosalie van; Hendriks, A. Jan; Bobbink, Roland; Huijbregts, Mark A.J.

    2013-01-01

    This study estimates the potential losses of vascular plant species richness due to terrestrial acidification for different world's biomes. We used empirical occurrence data of 2409 species from 140 studies and estimated the relative species richness – pH response curves using logistic regressions. The regressions were then used to quantify the fraction of species that are potentially lost due to soil pH changes. Although we found considerable variability within biomes, out results show that the pH at which species richness was maximized was found to be the lowest in (sub)tropical forests (pH = 4.1) and the highest in deserts (pH = 7.4). We also found that (sub)tropical moist forests are highly sensitive to decreases of in soil pH below 4.1. This study can be coupled with existing atmospheric deposition models to quantify the risk of species richness loss following soil acidification. Highlights: ► We compare the sensitivity of four biomes to soil acidification. ► We develop logistic regressions using observational field data. ► Sub(tropical) moist forests are highly affected by pH decreases. ► Logistic regressions can be linked to global scale atmospheric and soil fate models. -- Relationships of potential species richness loss along a soil pH gradient are proposed

  1. Roles of Solar Power from Space for Europe - Space Exploration and Combinations with Terrestrial Solar Plant Concepts

    Science.gov (United States)

    Summerer, L.; Pipoli, T.; Galvez, A.; Ongaro, F.; Vasile, M.

    The paper presents the prospective roles of SPS concepts for Europe, shows the outcome of recent studies undertaken by ESA's Advanced Concepts Team (ACT) together with European industry and research centres and gives insight into planned activities. The main focus is on the assessment of the principal validity and economic viability of solar power from space concepts in the light of advances in alternative sustainable, clean and potentially abundant solar-based terrestrial concepts. The paper takes into account expected changes in the European energy system (e.g. gradual introduction of hydrogen as energy vector). Special emphasis is given to the possibilities of integrating space and terrestrial solar plants. The relative geographic proximity of areas in North Africa with high average solar irradiation to the European energy consumer market puts Europe in a special position regarding the integration of space and terrestrial solar power concepts. The paper presents a method to optimise such an integration, taking into account different possible orbital constellations, terrestrial locations, plant number and sizes as well as consumer profiles and extends the scope from the European-only to a multi continental approach including the fast growing Chinese electricity market. The work intends to contribute to the discussion on long-term options for the European commitment to worldwide CO2 emission reduction. Cleaner electricity generation and environmentally neutral transport fuels (e.g. solar generated hydrogen) might be two major tools in reaching this goal.

  2. The Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM: a diverse approach to representing terrestrial biogeography and biogeochemistry based on plant functional trade-offs

    Directory of Open Access Journals (Sweden)

    R. Pavlick

    2013-06-01

    Full Text Available Terrestrial biosphere models typically abstract the immense diversity of vegetation forms and functioning into a relatively small set of predefined semi-empirical plant functional types (PFTs. There is growing evidence, however, from the field ecology community as well as from modelling studies that current PFT schemes may not adequately represent the observed variations in plant functional traits and their effect on ecosystem functioning. In this paper, we introduce the Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM as a new approach to terrestrial biosphere modelling with a richer representation of functional diversity than traditional modelling approaches based on a small number of fixed PFTs. JeDi-DGVM simulates the performance of a large number of randomly generated plant growth strategies, each defined by a set of 15 trait parameters which characterize various aspects of plant functioning including carbon allocation, ecophysiology and phenology. Each trait parameter is involved in one or more functional trade-offs. These trade-offs ultimately determine whether a strategy is able to survive under the climatic conditions in a given model grid cell and its performance relative to the other strategies. The biogeochemical fluxes and land surface properties of the individual strategies are aggregated to the grid-cell scale using a mass-based weighting scheme. We evaluate the simulated global biogeochemical patterns against a variety of field and satellite-based observations following a protocol established by the Carbon-Land Model Intercomparison Project. The land surface fluxes and vegetation structural properties are reasonably well simulated by JeDi-DGVM, and compare favourably with other state-of-the-art global vegetation models. We also evaluate the simulated patterns of functional diversity and the sensitivity of the JeDi-DGVM modelling approach to the number of sampled strategies. Altogether, the results demonstrate the

  3. Very small HTGR nuclear power plant concepts for special terrestrial applications

    International Nuclear Information System (INIS)

    McDonald, C.F.; Goodjohn, A.J.

    1983-01-01

    The role of the very small nuclear power plant, of a few megawatts capacity, is perceived to be for special applications where an energy source as required but the following prevail: 1) no indigenous fossil fuel source, in long transport distances that add substantially to the cost of oil, coal in gas, and 3) secure long-term power production for defense applications with freedom from fuel supply lines. A small High Temperature Gas-Cooled reactor (HTGR) plant could provide the total energy needs for 1) a military installation, 2) an island base of strategic significance, 3) an industrial community or 4) an urban area. The small HTGR is regarded as a fixed-base installation (as opposed to a mobile system). All of the major components would be factory fabricated and transported to the site where emphasis would be placed on minimizing the construction time. The very small HTGR plant, currently in an early stage of design definition, has the potential for meeting the unique needs of the small energy user in both the military and private sectors. The plant may find acceptance for specialized applications in the industrialized nations and to meet the energy needs of developing nations. Emphasis in the design has been placed on safety, simplicity and compactness

  4. Investigating Effects of Invasive Species on Plant Community Structure

    Science.gov (United States)

    Franklin, Wilfred

    2008-01-01

    In this article, the author presents a field study project that explores factors influencing forest community structure and lifts the veil off of "plant blindness." This ecological study consists of three laboratories: (1) preliminary field trip to the study site; (2) plant survey; and (3) analyzing plant community structure with descriptive…

  5. Monitoring and assessment of mercury pollution in the vicinity of a chloralkali plant. IV. Bioconcentration of mercury in in situ aquatic and terrestrial plants at Ganjam, India.

    Science.gov (United States)

    Lenka, M; Panda, K K; Panda, B B

    1992-02-01

    In situ aquatic and terrestrial plants including a few vegetable and crop plants growing in and around a chloralkali plant at Ganjam, India were analyzed for concentrations of root and shoot mercury. The aquatic plants found to bioconcentrate mercury to different degrees included Marsilea spp., Spirodela polyrhiza, Jussiea repens, Paspalum scrobiculatam, Pistia stratiotes, Eichhornia crassipes, Hygrophila schulli, Monochoria hastata and Bacopa monniera. Among wild terrestrial plants Chloris barbata, Cynodon dactylon, Cyperus rotundus and Croton bonplandianum were found growing on heavily contaminated soil containing mercury as high as 557 mg/kg. Analysis of mercury in root and shoot of these plants in relation to the mercury levels in soil indicated a significant correlation between soil and plant mercury with the exception of C. bonplandianum. Furthermore, the tolerance to mercury toxicity was highest with C. barbata followed by C. dactylon and C. rotundus, in that order. The rice plants analyzed from the surrounding agricultural fields did not show any significant levels of bioconcentrated mercury. Of the different vegetables grown in a contaminated kitchen garden with mercury level at 8.91 mg/kg, the two leafy vegetables, namely cabbage (Brassica oleracea) and amaranthus (Amaranthus oleraceous), were found to bioconcentrate mercury at statistically significant levels. The overall study indicates that the mercury pollution is very much localized to the specific sites in the vicinity of the chloralkali plant.

  6. Comparative Analysis of Chloroplast psbD Promoters in Terrestrial Plants

    Directory of Open Access Journals (Sweden)

    Shuichi Shimmura

    2017-07-01

    D-psbC operon. Light- and stress-induced transcription may have evolved independently and multiple times during terrestrial plant evolution.

  7. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  8. Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

    Science.gov (United States)

    Metcalfe, D. B.; Fisher, R. A.; Wardle, D. A.

    2011-03-01

    Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon balance of terrestrial ecosystems under climate change. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Plant species consistently exhibit cohesive suites of traits, linked to contrasting life history strategies, which exert a variety of impacts on R. As such, we propose that plant community shifts towards dominance by fast growing plants with nutrient rich litter could provide a major, though often neglected, positive feedback to climate change. Within vegetation types, belowground carbon flux will mainly be controlled by photosynthesis, while amongst vegetation types this flux will be more dependent upon the specific characteristics of the plant life form. We also make the case that community composition, rather than diversity, is usually the dominant control on ecosystem processes in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community, or modulates the occurrence of major natural disturbances. We show that climate-vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. This situation could, however, be relatively easily improved with targeted experimental and field studies. Finally, we identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits

  9. [Ecological risk assessment of dam construction for terrestrial plant species in middle reach of Lancangjiang River, Southwest China].

    Science.gov (United States)

    Li, Xiao-Yan; Dong, Shi-Kui; Liu, Shi-Liang; Peng, Ming-Chun; Li, Jin-Peng; Zhao, Qing-He; Zhang, Zhao-Ling

    2012-08-01

    Taking the surrounding areas of Xiaowan Reservoir in the middle reach of Lancangjiang River as study area, and based on the vegetation investigation at three sites including electricity transmission area (site 1), electricity-transfer substation and roadsides to the substation (site 2), and emigration area (site 3) in 1997 (before dam construction), another investigation was conducted on the vegetation composition, plant coverage, and dominant species at the same sites in 2010 (after dam construction), aimed to evaluate the ecological risk of the dam construction for the terrestrial plant species in middle reach of Lancangjiang River. There was an obvious difference in the summed dominance ratio of dominant species at the three sites before and after the dam construction. According the types of species (dominant and non-dominant species) and the changes of plant dominance, the ecological risk (ER) for the plant species was categorized into 0 to IV, i.e., no or extremely low ecological risk (0), low ecological risk (I), medium ecological risk (II), high ecological risk (III), and extremely high ecological risk (IV). As affected by the dam construction, the majority of the species were at ER III, and a few species were at ER IV. The percentage of the plant species at ER III and ER IV at site 3 was higher than that at sites 1 and 2. The decrease or loss of native plants and the increase of alien or invasive plants were the major ecological risks caused by the dam construction. Effective protection strategies should be adopted to mitigate the ecological risk of the dam construction for the terrestrial plants at species level.

  10. Sublethal effects of herbicides on the biomass and seed production of terrestrial non-crop plant species, influenced by environment, development stage and assessment date

    International Nuclear Information System (INIS)

    Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne; Lotz, Lambertus A.P.; Kropff, Martin J.J.

    2009-01-01

    Guidelines provided by the OECD and EPPO allow the use of single-species tests performed in greenhouses to assess the risk of herbicides to non-target terrestrial plant communities in the field. The present study was undertaken to investigate the use of greenhouse data to determine effects of herbicides with a different mode of action on the biomass, seed production and emergence of field-grown plants. In addition, a single species approach was compared with a mixed species approach. Effects on the biomass of greenhouse and field-grown plants were found to be related at different effect levels, indicating that it might be possible to translate results from greenhouse studies to field situations. However, the use of single-species tests may not be valid. The response of a single plant species to sublethal herbicide dosages differed to the response of the same species grown in a mixture with other species. - The use of single-species greenhouse tests in the ecological risk assessment of crop protection products may only be valid for single species in the field, not for vegetations.

  11. A thready affair: linking fungal diversity and community dynamics to terrestrial decomposition processes

    NARCIS (Netherlands)

    Van der Wal, A.; Geydan, T.D.; Kuyper, T.W.; De Boer, W.

    2013-01-01

    Filamentous fungi are critical to the decomposition of terrestrial organic matter and, consequently, in the global carbon cycle. In particular, their contribution to degradation of recalcitrant lignocellulose complexes has been widely studied. In this review, we focus on the functioning of

  12. Predicting sublethal effects of herbicides on terrestrial non-crop plant species in the field from greenhouse data

    International Nuclear Information System (INIS)

    Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne

    2008-01-01

    Guidelines provided by OECD and EPPO allow the use of data obtained in greenhouse experiments in the risk assessment for pesticides to non-target terrestrial plants in the field. The present study was undertaken to investigate the predictability of effects on field-grown plants using greenhouse data. In addition, the influence of plant development stage on plant sensitivity and herbicide efficacy, the influence of the surrounding vegetation on individual plant sensitivity and of sublethal herbicide doses on the biomass, recovery and reproduction of non-crop plants was studied. Results show that in the future, it might well be possible to translate results from greenhouse experiments to field situations, given sufficient experimental data. The results also suggest consequences at the population level. Even when only marginal effects on the biomass of non-target plants are expected, their seed production and thereby survival at the population level may be negatively affected. - The response of greenhouse-grown wild plant species to herbicide exposure could be related to the response of the same species when grown in the field

  13. Plant community variability on a small area in southeastern Montana

    Science.gov (United States)

    James G. MacCracken; Daniel W. Uresk; Richard M. Hansen

    1984-01-01

    Plant communities are inherently variable due to a number of environmental and biological forces. Canopy cover and aboveground biomass were determined for understory vegetation in plant communities of a prairie grassland-forest ecotone in southeastern Montana. Vegetation units were described using polar ordination and stepwise discriminant analysis. Nine of a total of...

  14. Plant community analysis and ecology of afromontane and ...

    African Journals Online (AJOL)

    The plant communities of the forests of southwestern Ethiopia were described based on floristic analysis of the data collected between February 1995 and May 1996. Floristic analysis is based on the cover-abundance values of both woody and herbaceous species. Plant community-environment relationship was assessed ...

  15. Joint control of terrestrial gross primary productivity by plant phenology and physiology

    DEFF Research Database (Denmark)

    Xia, Jianyang; Niu, Shuli; Ciais, Philippe

    2015-01-01

    Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate–carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of b...

  16. Characterisation of perfluorooctane sulfonate (PFOS) in a terrestrial ecosystem near a fluorochemical plant in Flanders, Belgium

    NARCIS (Netherlands)

    D'Hollander, W.; De Bruyn, L.; Hagenaars, A; de Voogt, P.; Bervoets, L.

    2014-01-01

    Bioaccumulation of perfluorooctane sulfonate (PFOS) in a restricted terrestrial food chain was investigated with the omnivorous wood mouse (Apodemus sylvaticus) on top of the studied food chain. The levels detected are very high compared with literature as a result of the presence of fluorochemical

  17. Joint control of terrestrial gross primary productivity by plant phenology and physiology

    NARCIS (Netherlands)

    Xia, J.; Niu, S.; Ciais, P.; Janssens, I.A.; Chen, J.; Ammann, C.; Arain, A.; Blanken, P.D.; Cescatti, A.; Moors, E.J.

    2015-01-01

    Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate–carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of

  18. Direct effect of acid rain on leaf chlorophyll content of terrestrial plants in China

    NARCIS (Netherlands)

    Du, Enzai; Dong, Dan; Zeng, Xuetong; Sun, Zhengzhong; Jiang, Xiaofei; Vries, de Wim

    2017-01-01

    Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial

  19. Variation pattern of terrestrial antibiotic resistances and bacterial communities in seawater/freshwater mixed microcosms.

    Science.gov (United States)

    Zhang, Kai; Zhang, Ying; Xin, Rui; Zhang, Yongpeng; Niu, Zhiguang

    2018-06-01

    The ocean is the final place where pollutants generated by human activities are deposited. As a result, the long-range transport of the ocean can facilitate the diffusion of terrestrial contaminants, including ARGs. However, to our knowledge, little research has been devoted to discussing the content change of terrestrial ARGs and the reason for the change in coastal area. This study established various microcosms, in which seawater and freshwater were mixed at different ratio to simulate the environmental conditions of different regions in coastal areas. Four ARGs were quantified, and 16S pyrosequencing was conducted. The results showed that the terrestrial ARGs influenced the concentration of the corresponding ARGs in coastal areas, and the content change pattern of each ARG was distinct. The influence of salinity on the ARG content was limited in most cases. Moreover, most dominant bacteria from freshwater had significant positive correlation (p prompt the growth of some bacteria (include potential hosts of ARGs) in coastal area. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Site and plant species are important determinants of the Methylobacterium community composition in the plant phyllosphere.

    Science.gov (United States)

    Knief, Claudia; Ramette, Alban; Frances, Lisa; Alonso-Blanco, Carlos; Vorholt, Julia A

    2010-06-01

    The plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus Methylobacterium. Owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. The influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on Methylobacterium community composition and population size were evaluated in this study. Leaf samples were collected from Arabidopsis thaliana or Medicago truncatula plants and from the surrounding plant species at several sites. The abundance of cultivable Methylobacterium clearly correlated with the abundance of other phyllosphere bacteria, suggesting that methylobacteria constitute a considerable and rather stable fraction of the phyllosphere microbiota under varying environmental conditions. Automated ribosomal intergenic spacer analysis (ARISA) was applied to characterize the Methylobacterium community composition and showed the presence of similar communities on A. thaliana plants at most sites in 2 consecutive years of sampling. A substantial part of the observed variation in the community composition was explained by site and plant species, especially in the case of the plants collected at the Arabidopsis sites (50%). The dominating ARISA peaks that were detected on A. thaliana plants were found on other plant species grown at the same site, whereas some different peaks were detected on A. thaliana plants from other sites. This indicates that site-specific factors had a stronger impact on the Methylobacterium community composition than did plant-specific factors and that the Methylobacterium-plant association is not highly host plant species specific.

  1. Soil-landform-plant communities relationships of a periglacial landscape at Potter Peninsula, Maritime Antarctica

    Science.gov (United States)

    Poelking, E. L.; Schaefer, C. E. R.; Fernandes Filho, E. I.; de Andrade, A. M.; Spielmann, A. A.

    2014-08-01

    Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of Maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on monitoring climate change in Maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated in Potter Peninsula, King George Island, Maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil-landform-vegetation relationships. The vegetation map was obtained by classification of a Quickbird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities at Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils with greater moisture or poorly drained, and acid to neutral pH, are favourable for mosses subformations. Saline, organic-matter rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felseenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens, at the highest surface. Lichens subformations cover the largest vegetated area, showing varying associations with mosses.

  2. Soil-landform-plant-community relationships of a periglacial landscape on Potter Peninsula, maritime Antarctica

    Science.gov (United States)

    Poelking, E. L.; Schaefer, C. E. R.; Fernandes Filho, E. I.; de Andrade, A. M.; Spielmann, A. A.

    2015-05-01

    Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on the monitoring of climate change in maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated on Potter Peninsula, King George Island, maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil-landform-vegetation relationships. The vegetation map was obtained by classification of a QuickBird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities on Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils that have greater moisture or are poorly drained, and with acid to neutral pH, are favourable for moss sub-formations. Saline, organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens at the highest surface. Lichens sub-formations cover the largest vegetated area, showing varying associations with mosses.

  3. Realistic diversity loss and variation in soil depth independently affect community-level plant nitrogen use.

    Science.gov (United States)

    Selmants, Paul C; Zavaleta, Erika S; Wolf, Amelia A

    2014-01-01

    Numerous experiments have demonstrated that diverse plant communities use nitrogen (N) more completely and efficiently, with implications for how species conservation efforts might influence N cycling and retention in terrestrial ecosystems. However, most such experiments have randomly manipulated species richness and minimized environmental heterogeneity, two design aspects that may reduce applicability to real ecosystems. Here we present results from an experiment directly comparing how realistic and randomized plant species losses affect plant N use across a gradient of soil depth in a native-dominated serpentine grassland in California. We found that the strength of the species richness effect on plant N use did not increase with soil depth in either the realistic or randomized species loss scenarios, indicating that the increased vertical heterogeneity conferred by deeper soils did not lead to greater complementarity among species in this ecosystem. Realistic species losses significantly reduced plant N uptake and altered N-use efficiency, while randomized species losses had no effect on plant N use. Increasing soil depth positively affected plant N uptake in both loss order scenarios but had a weaker effect on plant N use than did realistic species losses. Our results illustrate that realistic species losses can have functional consequences that differ distinctly from randomized losses, and that species diversity effects can be independent of and outweigh those of environmental heterogeneity on ecosystem functioning. Our findings also support the value of conservation efforts aimed at maintaining biodiversity to help buffer ecosystems against increasing anthropogenic N loading.

  4. Plant community resistance to invasion by Bromus species: The roles of community attributes, Bromus interactions with plant communities, and Bromus traits [Chapter 10

    Science.gov (United States)

    Jeanne C. Chambers; Matthew J. Germino; Jayne Belnap; Cynthia S. Brown; Eugene W. Schupp; Samuel B. St. Clair

    2016-01-01

    The factors that determine plant community resistance to exotic annual Bromus species (Bromus hereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in...

  5. Evaluation of the radionuclide concentrations in soil and plants from the 1975 terrestrial survey of Bikini and Eneu Islands

    International Nuclear Information System (INIS)

    Colsher, C.S.; Robison, W.L.; Gudiksen, P.H.

    1977-01-01

    In June 1975 a radiological survey was conducted of the terrestrial environment of Bikini and Eneu islands (Bikini Atoll) to evaluate the potential radiation dose to the returning Bikini population. In this report, we present measurements of the radionuclide concentration in soil profiles and in dominant species of edible and nonedible, indicator plants. The use of these data to derive relationships to predict the plant uptake of radionuclides from soil is described. Approximately 620 soil and vegetation samples from Bikini and Eneu Islands were analyzed by Ge(Li) gamma spectrometry and by wet chemistry. The predominant radionuclides in these samples were 60 Co, 90 Sr, 137 Cs, /sup 239,240/Pu, 241 Pu, and 241 Am

  6. Not all trees sleep the same - High temporal resolution terrestrial laser scanning shows differences in nocturnal plant movement

    DEFF Research Database (Denmark)

    Zlinszky, András; Barfod, Anders; Molnár, Bence

    2017-01-01

    Circadian leaf movements are widely known in plants, but nocturnal movement of tree branches were only recently discovered by using terrestrial laser scanning (TLS), a high resolution three-dimensional surveying technique. TLS uses a pulsed laser emitted in a regular scan pattern for rapid...... surveyed a series of 18 full scans over a 12-h night period to measure nocturnal changes in shape simultaneously for an experimental setup of 22 plants representing different species. Resulting point clouds were evaluated by comparing changes in height percentiles of laser scanning points belonging...... to the canopy. Changes in crown shape were observed for all studied trees, but clearly distinguishable sleep movements are apparently rare. Ambient light conditions were continuously dark between sunset (7:30 p.m.) and sunrise (6:00 a.m.), but most changes in movement direction occurred during this period, thus...

  7. Plant toxicity, adaptive herbivory, and plant community dynamics

    Science.gov (United States)

    Feng, Z.; Liu, R.; DeAngelis, D.L.; Bryant, J.P.; Kielland, K.; Stuart, Chapin F.; Swihart, R.K.

    2009-01-01

    We model effects of interspecific plant competition, herbivory, and a plant's toxic defenses against herbivores on vegetation dynamics. The model predicts that, when a generalist herbivore feeds in the absence of plant toxins, adaptive foraging generally increases the probability of coexistence of plant species populations, because the herbivore switches more of its effort to whichever plant species is more common and accessible. In contrast, toxin-determined selective herbivory can drive plant succession toward dominance by the more toxic species, as previously documented in boreal forests and prairies. When the toxin concentrations in different plant species are similar, but species have different toxins with nonadditive effects, herbivores tend to diversify foraging efforts to avoid high intakes of any one toxin. This diversification leads the herbivore to focus more feeding on the less common plant species. Thus, uncommon plants may experience depensatory mortality from herbivory, reducing local species diversity. The depensatory effect of herbivory may inhibit the invasion of other plant species that are more palatable or have different toxins. These predictions were tested and confirmed in the Alaskan boreal forest. ?? 2009 Springer Science+Business Media, LLC.

  8. Stoichiometric imbalances between terrestrial decomposer communities and their resources: mechanisms and implications of microbial adaptations to their resources

    Directory of Open Access Journals (Sweden)

    Maria eMooshammer

    2014-02-01

    Full Text Available Terrestrial microbial decomposer communities thrive on a wide range of organic matter types that rarely ever meet their elemental demands. In this review we synthesize the current state-of-the-art of microbial adaptations to resource stoichiometry, in order to gain a deeper understanding of the interactions between heterotrophic microbial communities and their chemical environment. The stoichiometric imbalance between microbial communities and their organic substrates generally decreases from wood to leaf litter and further to topsoil and subsoil organic matter. Microbial communities can respond to these imbalances in four ways: first, they adapt their biomass composition towards their resource in a non-homeostatic behaviour. Such changes are, however, only moderate, and occur mainly because of changes in microbial community structure and less so due to cellular storage of elements in excess. Second, microbial communities can mobilize resources that meet their elemental demand by producing specific extracellular enzymes, which, in turn, is restricted by the C and N requirement for enzyme production itself. Third, microbes can regulate their element use efficiencies (ratio of element invested in growth over total element uptake, such that they release elements in excess depending on their demand (e.g., respiration and N mineralization. Fourth, diazotrophic bacteria and saprotrophic fungi may trigger the input of external N and P to decomposer communities. Theoretical considerations show that adjustments in element use efficiencies may be the most important mechanism by which microbes regulate their biomass stoichiometry. This review summarizes different views on how microbes cope with imbalanced supply of C, N and P, thereby providing a framework for integrating and linking microbial adaptation to resource imbalances to ecosystem scale fluxes across scales and ecosystems.

  9. Plant selenium hyperaccumulation- Ecological effects and potential implications for selenium cycling and community structure.

    Science.gov (United States)

    Reynolds, R Jason B; Pilon-Smits, Elizabeth A H

    2018-04-25

    Selenium (Se) hyperaccumulation occurs in ~50 plant taxa native to seleniferous soils in Western USA. Hyperaccumulator tissue Se levels, 1000-15,000 mg/kg dry weight, are typically 100 times higher than surrounding vegetation. Relative to other species, hyperaccumulators also transform Se more into organic forms. We review abiotic and biotic factors influencing soil Se distribution and bioavailability, soil being the source of the Se in hyperaccumulators. Next, we summarize the fate of Se in plants, particularly hyperaccumulators. We then extensively review the impact of plant Se accumulation on ecological interactions. Finally, we discuss the potential impact of Se hyperaccumulators on local community composition and Se cycling. Selenium (hyper)accumulation offers ecological advantages: protection from herbivores and pathogens and competitive advantage over other plants. The extreme Se levels in and around hyperaccumulators create a toxic environment for Se-sensitive ecological partners, while offering a niche for Se-resistant partners. Through these dual effects, hyperaccumulators may influence species composition in their local environment, as well as Se cycling. The implied effects of Se hyperaccumulation on community assembly and local Se cycling warrant further investigations into the contribution of hyperaccumulators and general terrestrial vegetation to global Se cycling and may serve as a case study for how trace elements influence ecological processes. Furthermore, understanding ecological implications of plant Se accumulation are vital for safe implementation of biofortification and phytoremediation, technologies increasingly implemented to battle Se deficiency and toxicity. Copyright © 2018. Published by Elsevier B.V.

  10. Evolutionary history of callose synthases in terrestrial plants with emphasis on proteins involved in male gametophyte development.

    Directory of Open Access Journals (Sweden)

    Lenka Záveská Drábková

    Full Text Available Callose is a plant-specific polysaccharide (β-1,3-glucan playing an important role in angiosperms in many developmental processes and responses to biotic and abiotic stresses. Callose is synthesised at the plasma membrane of plant cells by callose synthase (CalS and, among others, represents the main polysaccharide in the callose wall surrounding the tetrads of developing microspores and in the growing pollen tube wall. CalS proteins involvement in spore development is a plesiomorphic feature of terrestrial plants, but very little is known about their evolutionary origin and relationships amongst the members of this protein family. We performed thorough comparative analyses of callose synthase family proteins from major plant lineages to determine their evolutionary history across the plant kingdom. A total of 1211 candidate CalS sequences were identified and compared amongst diverse taxonomic groups of plants, from bryophytes to angiosperms. Phylogenetic analyses identified six main clades of CalS proteins and suggested duplications during the evolution of specialised functions. Twelve family members had previously been identified in Arabidopsis thaliana. We focused on five CalS subfamilies directly linked to pollen function and found that proteins expressed in pollen evolved twice. CalS9/10 and CalS11/12 formed well-defined clades, whereas pollen-specific CalS5 was found within subfamilies that mostly did not express in mature pollen vegetative cell, although were found in sperm cells. Expression of five out of seven mature pollen-expressed CalS genes was affected by mutations in bzip transcription factors. Only three subfamilies, CalS5, CalS10, and CalS11, however, formed monophyletic, mostly conserved clades. The pairs CalS9/CalS10, CalS11/CalS12 and CalS3 may have diverged after angiosperms diversified from lycophytes and bryophytes. Our analysis of fully sequenced plant proteins identified new evolutionary lineages of callose synthase

  11. Variation in the Apparent Biosynthetic Fractionation for N-alkane δD Among Terrestrial Plants: Patterns, Mechanisms, and Implications

    Science.gov (United States)

    Johnson, J. E.; Tipple, B. J.; Betancourt, J. L.; Ehleringer, J. R.; Leavitt, S. W.; Monson, R. K.

    2016-12-01

    Long-chain normal alkanes (n-alkanes) are a component of the leaf cuticle of all terrestrial plants. Since the hydrogen in the n-alkanes is derived from the hydrogen in plants' water sources and is non-exchangeable, the stable hydrogen isotopic composition (δD) of the n-alkanes provides information about the δD of environmental waters. While this relationship creates opportunities for using n-alkane δD for process-based reconstructions of δD of environmental waters, progress in this direction is currently constrained by the observation that terrestrial plants exhibit a startlingly wide range of apparent biosynthetic fractionations. To understand the mechanisms responsible for variation in the apparent biosynthetic fractionations, we compared measurements and models of δD for n-C29 in a water-limited ecosystem where the timing of primary and secondary cuticle deposition is closely coupled to water availability (Tumamoc Hill, Tucson, Arizona, USA). During the 2014-2015 hydrologic year, the most widespread and abundant plant species at this site exhibited δD for n-C29 varying over a total range of 102‰. Discrete samples of leaf water collected at the same time as the n-C29 samples exhibited δD varying over a total range of only 53‰, but a continuous model of leaf water through the annual cycle predicted δD varying over a total range of 190‰. These results indicate that the observed variation in the apparent biosynthetic fractionation for n-C29 δD could be primarily attributable to leaf water dynamics that are temporally uncoupled from primary and secondary cuticle deposition. If a single biosynthetic fractionation does describe the relationship between the δD of n-alkanes and leaf water during intervals of cuticle deposition, it will facilitate process-based interpretations of n-alkane δD values in ecological, hydrological, and climatological studies of modern and ancient terrestrial environments.

  12. Ancient ecology of 15-million-year-old browsing mammals within C3 plant communities from Panama.

    Science.gov (United States)

    MacFadden, Bruce J; Higgins, Pennilyn

    2004-06-01

    Middle Miocene mammals are known from approximately 15 million-year-old sediments exposed along the Panama Canal of Central America, a region that otherwise has an exceedingly poor terrestrial fossil record. These land mammals, which represent a part of the ancient terrestrial herbivore community, include an oreodont Merycochoerus matthewi, small camel-like protoceratid artiodactyl Paratoceras wardi, two horses Anchitherium clarencei and Archaeohippus sp., and two rhinos Menoceras barbouri and Floridaceras whitei. Bulk and serial carbon and oxygen isotope analyses of the tooth enamel carbonate allow reconstruction of the ancient climate and ecology of these fossil mammals. Ancient Panama had an equable climate with seasonal temperature and rainfall fluctuations less than those seen today. The middle Miocene terrestrial community consisted predominantly, or exclusively, of C3 plants, i.e., there is no evidence for C4 grasses. Statistically different mean carbon isotope values for the mammalian herbivores indicate niche partitioning of the C3 plant food resources. The range of individual carbon isotope analyses, i.e., delta13C from -15.9 to -10.1 per thousand, indicates herbivores feeding on diverse plants from different habitats with extrapolated delta13C values of -29.9 to -24.2 per thousand, possibly ranging from dense forest to more open country woodland. The ecological niches of individual mammalian herbivore species were differentiated either by diet or body size.

  13. Disruption of the terrestrial plant ecosystem at the Cretaceous-Tertiary boundary, western interior

    Science.gov (United States)

    Tschudy, R.H.; Pillmore, C.L.; Orth, C.J.; Gilmore, J.S.; Knight, J.D.

    1984-01-01

    The palynologically defined Cretaceous-Tertiary boundary in the western interior of North America occurs at the top of an iridium-rich clay layer. The boundary is characterized by the abrupt disappearance of certain pollen species, immediately followed by a pronounced, geologically brief change in the ratio of fern spores to angiosperm pollen. The occurrence of these changes at two widely separated sites implies continentwide disruption of the terrestrial ecosystem, probably caused by a major catastrophic event at the end of the period.

  14. Abiotic drivers of Chihuahuan Desert plant communities

    Science.gov (United States)

    Laura Marie Ladwig

    2014-01-01

    Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...

  15. Annotation of Selaginella moellendorffii major intrinsic proteins and the evolution of the protein family in terrestrial plants

    Directory of Open Access Journals (Sweden)

    Hanna Isa Anderberg

    2012-02-01

    Full Text Available Major intrinsic proteins (MIPs also called aquaporins form pores in membranes to facilitate the permeation of water and certain small polar solutes across membranes. MIPs are present in virtually every organism but are uniquely abundant in land plants. To elucidate the evolution and function of MIPs in terrestrial plants, the MIPs encoded in the genome of the spikemoss Selaginella moellendorffii were identified and analyzed. In total 19 MIPs were found in S. moellendorffii belonging to six of the seven MIP subfamilies previously identified in the moss Physcomitrella patens. Only three of the MIPs were classified as members of the conserved water specific plasma membrane intrinsic protein (PIP subfamily whereas almost half were found to belong to the diverse NOD26-like intrinsic protein (NIP subfamily permeating various solutes. The small number of PIPs in S. moellendorffii is striking compared to all other land plants and no other species has more NIPs than PIPs. Similar to moss, S. moellendorffii only has one type of tonoplast intrinsic protein (TIP. Based on ESTs from non-angiosperms we conclude that the specialized groups of TIPs present in higher plants are not found in primitive vascular plants but evolved later in a common ancestor of seed plants. We also note that the silicic acid permeable NIP2 group that has been reported from angiosperms appears at the same time. We suggest that the expansion of the number MIP isoforms in higher plants is primarily associated with an increase in the different types of specialized tissues rather than the emergence of vascular tissue per se and that the loss of subfamilies has been possible due to a functional overlap between some subfamilies.

  16. Herbivory and dominance shifts among exotic and congeneric native plant species during plant community establishment

    DEFF Research Database (Denmark)

    Engelkes, Tim; Meisner, Annelein; Morriën, Elly

    2016-01-01

    in a riparian ecosystem during early establishment of invaded communities. We planted ten plant communities each consisting of three individuals of each of six exotic plant species as well as six phylogenetically related natives. Exotic plant species were selected based on a rapid recent increase in regional...... abundance, the presence of a congeneric native species, and their co-occurrence in the riparian ecosystem. All plant communities were covered by tents with insect mesh. Five tents were open on the leeward side to allow herbivory. The other five tents were completely closed in order to exclude insects...... and vertebrates. Herbivory reduced aboveground biomass by half and influenced which of the plant species dominated the establishing communities. Exposure to herbivory did not reduce the total biomass of natives more than that of exotics, so aboveground herbivory did not selectively enhance exotics during...

  17. Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

    Directory of Open Access Journals (Sweden)

    D. B. Metcalfe

    2011-08-01

    Full Text Available Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R is a key prerequisite for accurate prediction of the future carbon (C balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil – such as soil microbes, plant roots and their mycorrhizal symbionts – each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge.

    Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future

  18. Interaction of historical and nonhistorical disturbances maintains native plant communities.

    Science.gov (United States)

    Davies, K W; Svejcar, T J; Bates, J D

    2009-09-01

    Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.

  19. Measuring competition in plant communities where it is difficult to distinguish individual plants

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2011-01-01

    A novel method for measuring plant-plant interactions in undisturbed semi-natural and natural plant communities where it is difficult to distinguish individual plants is discussed. It is assumed that the ecological success of the different plant species in the plant community may be adequately...... measured by plant cover and vertical density (a measure that is correlated to the 3-dimensional space occupancy and biomass). Both plant cover and vertical density are measured in a standard pin-point analysis in the beginning and at the end of the growing season. In the outlined competition model....... The method allows direct measurements of the competitive effects of neighbouringzplants on plant performance and the estimation of parameters that describe the ecological processes of plantplant interactions during the growing season as well as the process of survival and recruitment between growing seasons...

  20. Evapotranspiration in three plant communities of a Rhigozum ...

    African Journals Online (AJOL)

    Evapotranspiration losses in three Rhigozum trichotomum plant communities namely, pure grass, pure R. trichotomum and a mixed stand of grass and R. trichotomum were determined during the 1985-86 growing season. Three hydrologically isolated plots in each community type were irrigated and changes in soil water ...

  1. Vertebrate herbivores influence soil nematodes by modifying plant communities

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Olff, Han; Duyts, Henk; van der Putten, Wim H.

    Abiotic soil properties, plant community composition, and herbivory all have been reported as important factors influencing the composition of soil communities. However, most studies thus far have considered these factors in isolation, whereas they strongly interact in the field. Here, we study how

  2. Response of native insect communities to invasive plants.

    Science.gov (United States)

    Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

    2014-01-01

    Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

  3. Comparative radiocarbon dating of terrestrial plant macrofossils and aquatic moss from the ice-free corridor of western Canada

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, G.M.; Beukens, R.P.; Kieser, W.E.; Vitt, D.H.

    1987-09-01

    In order to assess the reliability of aquatic moss for radiocarbon dating, /sup 14/C analyses were performed on a stratigraphic series of terrestrial plant macrofossils and samples of Drepanocladus crassicostatus from a small, hard-water lake (pH = 8.2) in the ice-free corridor of Alberta. All /sup 14/C dating was done by using accelerator mass spectrometry. Mazama Ash provided an independent chronological control. The aquatic bryophyte samples consistently produced /sup 14/C ages significantly older than the terrestrial macrofossils. The relation between the radiocarbon dates from the macrofossils and the moss was not linear, and age differences ranged from approximately 1400 to 6400 yr. The /sup 14/C content of D. crassicostatus growing in the lake at present was less than 85% modern. Despite the apparent inability to take up /sup 14/C-deficient carbon by the direct incorporation of bicarbonate, the bryophytes clearly do not provide reliable material /sup 14/C dating. The /sup 14/C deficiency of aquatic mosses may be explained by the generation of /sup 14/C-deficient CO/sub 2/ through isotopic exchange, the formation of CO/sub 2/ from bicarbonate by chemical processes, and metabolic CO/sub 2/ production. These results demonstrate the potential unreliability of /sup 14/C dates from aquatic mosses and raise serious concerns about the deglaciation dates from the ice-free corridor that were obtained from aquatic Drepanocladus.

  4. Is ornithogenic fertilization important for collembolan communities in Arctic terrestrial ecosystems?

    Directory of Open Access Journals (Sweden)

    Katarzyna Zmudczyńska-Skarbek

    2015-07-01

    Full Text Available In the Arctic, areas close to seabird colonies are often characterized by exceptionally rich vegetation communities linked with the high nutrient subsidies transported by seabirds from the marine environment to the land. These areas also support soil invertebrate communities of which springtails (Collembola often represent the most abundant and diverse group. Our study focused on springtail community composition in the vicinity of seabird (little auk, great skua and glaucous gull nesting areas in different parts of Svalbard (Magdalenefjorden, Isfjorden and Bjørnøya, and on their comparison with adjacent areas not impacted by seabirds. Out of a total of 35 springtail species recorded, seven were found only within the ornithogenically influenced sites. Although geographical location was the strongest factor differentiating these springtail communities, ornithogenic influence was also significant regardless of the location. When each location was considered separately, seabirds were responsible for a relatively small but strongly significant proportion (8.6, 5.2 and 3.9%, respectively, for each site of total springtail community variability. Species whose occurrence was positively correlated with seabird presence were Folsomia coeruleogrisea, Friesea quinquespinosa, Lepidocyrtus lignorum and Oligaphorura groenlandica near Magdalenefjorden, Arrhopalites principalis, Folsomia bisetosella and Protaphorura macfadyeni in Isfjorden, and Folsomia quadrioculata on Bjørnøya.

  5. Conservation and restoration of indigenous plants to improve community livelihoods: the Useful Plants Project

    Science.gov (United States)

    Ulian, Tiziana; Sacandé, Moctar; Mattana, Efisio

    2014-05-01

    Kew's Millennium Seed Bank partnership (MSBP) is one of the largest ex situ plant conservation initiatives, which is focused on saving plants in and from regions most at risk, particularly in drylands. Seeds are collected and stored in seed banks in the country of origin and duplicated in the Millennium Seed Bank in the UK. The MSBP also strengthens the capacity of local communities to successfully conserve and sustainably use indigenous plants, which are important for their wellbeing. Since 2007, high quality seed collections and research information have been gathered on ca. 700 useful indigenous plant species that were selected by communities in Botswana, Kenya, Mali, Mexico and South Africa through Project MGU - The Useful Plants Project. These communities range from various farmer's groups and organisations to traditional healers, organic cotton/crop producers and primary schools. The information on seed conservation and plant propagation was used to train communities and to propagate ca. 200 species that were then planted in local gardens, and as species reintroduced for reforestation programmes and enriching village forests. Experimental plots have also been established to further investigate the field performance (plant survival and growth rate) of indigenous species, using low cost procedures. In addition, the activities support revenue generation for local communities directly through the sustainable use of plant products or indirectly through wider environmental and cultural services. This project has confirmed the potential of biodiversity conservation to improve food security and human health, enhance community livelihoods and strengthen the resilience of land and people to the changing climate. This approach of using indigenous species and having local communities play a central role from the selection of species to their planting and establishment, supported by complementary research, may represent a model for other regions of the world, where

  6. Plant community mediation of ecosystem responses to global change factors

    Science.gov (United States)

    Churchill, A. C.

    2017-12-01

    Human alteration of the numerous environmental drivers affecting ecosystem processes is unprecedented in the last century, including changes in climate regimes and rapid increases in the availability of biologically active nitrogen (N). Plant communities may offer stabilizing or amplifying feedbacks mediating potential ecosystem responses to these alterations, and my research seeks to examine the conditions associated with when plant feedbacks are important for ecosystem change. My dissertation research focused on the unintended consequences of N deposition into natural landscapes, including alpine ecosystems which are particularly susceptible to adverse environmental impacts. In particular, I examined alpine plant and soil responses to N deposition 1) across multiple spatial scales throughout the Southern Rocky Mountains, 2) among diverse plant communities associated with unique environmental conditions common in the alpine of this region, and 3) among ecosystem pools of N contributing to stabilization of N inputs within those communities. I found that communities responded to inputs of N differently, often associated with traits of dominant plant species but these responses were intimately linked with the abiotic conditions of each independent community. Even so, statistical models predicting metrics of N processing in the alpine were improved by encompassing both abiotic and biotic components of the main community types.

  7. Responses of Aquatic Bacteria to Terrestrial Runoff: Effects on Community Structure and Key Taxonomic Groups

    Science.gov (United States)

    Le, Huong T.; Ho, Cuong T.; Trinh, Quan H.; Trinh, Duc A.; Luu, Minh T. N.; Tran, Hai S.; Orange, Didier; Janeau, Jean L.; Merroune, Asmaa; Rochelle-Newall, Emma; Pommier, Thomas

    2016-01-01

    Organic fertilizer application is often touted as an economical and effective method to increase soil fertility. However, this amendment may increase dissolved organic carbon (DOC) runoff into downstream aquatic ecosystems and may consequently alter aquatic microbial community. We focused on understanding the effects of DOC runoff from soils amended with compost, vermicompost, or biochar on the aquatic microbial community of a tropical reservoir. Runoff collected from a series of rainfall simulations on soils amended with different organic fertilizers was incubated for 16 days in a series of 200 L mesocosms filled with water from a downstream reservoir. We applied 454 high throughput pyrosequencing for bacterial 16S rRNA genes to analyze microbial communities. After 16 days of incubation, the richness and evenness of the microbial communities present decreased in the mesocosms amended with any organic fertilizers, except for the evenness in the mesocosms amended with compost runoff. In contrast, they increased in the reservoir water control and soil-only amended mesocosms. Community structure was mainly affected by pH and DOC concentration. Compared to the autochthonous organic carbon produced during primary production, the addition of allochthonous DOC from these organic amendments seemed to exert a stronger effect on the communities over the period of incubation. While the Proteobacteria and Actinobacteria classes were positively associated with higher DOC concentration, the number of sequences representing key bacterial groups differed between mesocosms particularly between the biochar runoff addition and the compost or vermi-compost runoff additions. The genera of Propionibacterium spp. and Methylobacterium spp. were highly abundant in the compost runoff additions suggesting that they may represent sentinel species of complex organic carbon inputs. Overall, this work further underlines the importance of studying the off-site impacts of organic fertilizers as

  8. Terrestrial Species in Protected Areas and Community-Managed Lands in Arunachal Pradesh, Northeast India

    Directory of Open Access Journals (Sweden)

    Nandini Velho

    2016-10-01

    Full Text Available Protected areas (including areas that are nominally fully protected and those managed for multiple uses encompass about a quarter of the total tropical forest estate. Despite growing interest in the relative value of community-managed lands and protected areas, knowledge about the biodiversity value that each sustains remains scarce in the biodiversity-rich tropics. We investigated the species occurrence of a suite of mammal and pheasant species across four protected areas and nearby community-managed lands in a biodiversity hotspot in northeast India. Over 2.5 years we walked 98 transects (half of which were resampled on a second occasion across the four paired sites. In addition, we interviewed 84 key informants to understand their perceptions of species trends in these two management regimes. We found that protected areas had higher overall species richness and were important for species that were apparently declining in occurrence. On a site-specific basis, community-managed lands had species richness and occurrences comparable to those of a protected area, and in one case their relative abundances of mammals were higher. Interviewees indicated declines in the abundances of larger-bodied species in community-managed lands. Their observations agreed with our field surveys for certain key, large-bodied species, such as gaur and sambar, which generally occurred less in community-managed lands. Hence, the degree to which protected areas and community-managed lands protect wildlife species depends upon the species in question, with larger-bodied species usually faring better within protected areas.

  9. New perspectives on the ecology of tree structure and tree communities through terrestrial laser scanning.

    Science.gov (United States)

    Malhi, Yadvinder; Jackson, Tobias; Patrick Bentley, Lisa; Lau, Alvaro; Shenkin, Alexander; Herold, Martin; Calders, Kim; Bartholomeus, Harm; Disney, Mathias I

    2018-04-06

    Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do. Here we focus on the ecological challenges and benefits of understanding tree form, and highlight some advances related to capturing and describing tree shape that are becoming possible with the advent of TLS. We present examples of ongoing work that applies, or could potentially apply, new TLS measurements to better understand the constraints on optimization of tree form. Theories of resource distribution networks, such as metabolic scaling theory, can be tested and further refined. TLS can also provide new approaches to the scaling of woody surface area and crown area, and thereby better quantify the metabolism of trees. Finally, we demonstrate how we can develop a more mechanistic understanding of the effects of avoidance of wind risk on tree form and maximum size. Over the next few years, TLS promises to deliver both major empirical and conceptual advances in the quantitative understanding of trees and tree-dominated ecosystems, leading to advances in understanding the ecology of why trees and ecosystems look and grow the way they do.

  10. Plant species and soil type cooperatively shape the structure and function of microbial communities in the rhizosphere.

    Science.gov (United States)

    Berg, Gabriele; Smalla, Kornelia

    2009-04-01

    The rhizosphere is of central importance not only for plant nutrition, health and quality but also for microorganism-driven carbon sequestration, ecosystem functioning and nutrient cycling in terrestrial ecosystems. A multitude of biotic and abiotic factors are assumed to influence the structural and functional diversity of microbial communities in the rhizosphere. In this review, recent studies on the influence of the two factors, plant species and soil type, on rhizosphere-associated microbial communities are discussed. Root exudates and the response of microorganisms to the latter as well as to root morphology were shown to shape rhizosphere microbial communities. All studies revealed that soil is the main reservoir for rhizosphere microorganisms. Many secrets of microbial life in the rhizosphere were recently uncovered due to the enormous progress in molecular and microscopic tools. Physiological and molecular data on the factors that drive selection processes in the rhizosphere are presented here. Furthermore, implications for agriculture, nature conservation and biotechnology will also be discussed.

  11. A comparative phylogenetic analysis of medicinal plant Tribulus terrestris in Northwest India revealed by RAPD and ISSR markers

    Directory of Open Access Journals (Sweden)

    ASHWANI KUMAR

    2012-07-01

    Full Text Available Kumar A, Verma N. 2012. A comparative phylogenetic analysis of medicinal plant Tribulus terrestris in Northwest India revealed by RAPD and ISSR markers. Biodiversitas 13: 107-113. Several DNA marker systems and associated techniques are available today for fingerprinting of plant varieties. A total of 5 RAPD and 8 ISSR primers were used. Amplification of genomic DNA of the 6 genotypes, using RAPD analysis, yielded 164 fragments that could be scored, of which 47 were polymorphic, with an average of 9.4 polymorphic fragments per primer. Number of amplified fragments with random primers ranged from 6 (AKR-1 to 10 (AKR-4 and varied in size from 200 bp to 2,500 bp. Percentage polymorphism ranged from 16% (AKR-4 to a maximum of 41% (AKR-4, with an average of 29.6%. The 8 ISSR primers used in the study produced 327 bands across 6 genotypes, of which 114 were polymorphic. The number of amplified bands varied from 7 (ISSR 7 to 12 (ISSR 1&3, with a size range of 250-2,800 bp. The average numbers of bands per primer and polymorphic bands per primer were 40.87 and 14.25, respectively. Percentage polymorphism ranged from 24% (ISSR 4 to 53.84% (ISSR 2, with an average percentage polymorphism of 35.59% across all the genotypes. The 3′-anchored primers based on poly (AC and poly (AT motifs produced high average polymorphisms of 53.84% and 40.81%, respectively. ISSR markers were more efficient than the RAPD assay, as they detected 35.59% polymorphic DNA markers in Tribulus terrestris as compared to 29.6% for RAPD markers. Clustering of genotypes within groups was not similar when RAPD and ISSR derived dendrogram were compared, whereas the pattern of clustering of the genotypes remained more or less the same in ISSR and combined data of RAPD and ISSR.

  12. Ring-testing and field-validation of a terrestrial model ecosystem (TME) - An instrument for testing potentially harmful substances: effects of carbendazim on soil microarthropod communities.

    NARCIS (Netherlands)

    Koolhaas, J.E.; van Gestel, C.A.M.; Römbke, J.; Soares, A.M.V.M.; Jones, S.E.

    2004-01-01

    The effects of the fungicide carbendazim (applied in the formulation Derosal) on soil microarthropod communities was determined in three Terrestrial Model Ecosystem (TME) tests and a field-validation study for a period of 16 weeks after application. TMEs consisted of intact soil columns (diameter

  13. Rural and school community in appreciating knowledge on medical plants

    Directory of Open Access Journals (Sweden)

    Marcílio Souza Carneiro

    2016-05-01

    Isolated communities in the urban environment still use medicinal plants, but such knowledge is not always passed on to new generations. In this scenario, we propose a study with students, teachers, and community residents from Córrego da Ema, Amontada, Ceará, Brazil, aiming to know the wisdom of medicinal plants in a small rural community in the Brazilian semi-arid region. We interviewed the medicinal plant connoisseurs, named as local experts, by using the “snow ball” method. We applied questionnaires to investigate Elementary School students’ knowledge on medicinal plants (pre-tour. These actions provided a basis for planning guided-tours, activities aimed at 51 students, which we carried out along with the 10 experts and 2 local school teachers, whose results (post-tour were assessed by using the same pre-tour questionnaire. Most local experts were women (80%, their families had many people and low education level, factors that contribute to using medicinal plants. Experts cited 35 medicinal plant species. Students cited 24 pre-tour plant species and 28 post-tour plant species. Students increased their knowledge, as there was also a post-tour increase in therapeutic indications and preparation methods, as mentioned. The school played an important role in appreciating this intangible heritage, because it enabled actions involving formal and informal education.

  14. Rural and school community in appreciating knowledge on medical plants

    Directory of Open Access Journals (Sweden)

    Marcílio Souza Carneiro

    2016-05-01

    Full Text Available Isolated communities in the urban environment still use medicinal plants, but such knowledge is not always passed on to new generations. In this scenario, we propose a study with students, teachers, and community residents from Córrego da Ema, Amontada, Ceará, Brazil, aiming to know the wisdom of medicinal plants in a small rural community in the Brazilian semi-arid region. We interviewed the medicinal plant connoisseurs, named as local experts, by using the “snow ball” method. We applied questionnaires to investigate Elementary School students’ knowledge on medicinal plants (pre-tour. These actions provided a basis for planning guided-tours, activities aimed at 51 students, which we carried out along with the 10 experts and 2 local school teachers, whose results (post-tour were assessed by using the same pre-tour questionnaire. Most local experts were women (80%, their families had many people and low education level, factors that contribute to using medicinal plants. Experts cited 35 medicinal plant species. Students cited 24 pre-tour plant species and 28 post-tour plant species. Students increased their knowledge, as there was also a post-tour increase in therapeutic indications and preparation methods, as mentioned. The school played an important role in appreciating this intangible heritage, because it enabled actions involving formal and informal education.

  15. Plant species richness sustains higher trophic levels of soil nematode communities after consecutive environmental perturbations.

    Science.gov (United States)

    Cesarz, Simone; Ciobanu, Marcel; Wright, Alexandra J; Ebeling, Anne; Vogel, Anja; Weisser, Wolfgang W; Eisenhauer, Nico

    2017-07-01

    The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

  16. Quaternary ammonium salts with tetrafluoroborate anion: Phytotoxicity and oxidative stress in terrestrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Biczak, Robert, E-mail: r.biczak@ajd.czest.pl

    2016-03-05

    Highlights: • The level of oxidative stress in mono- and dicotyledonous plants was comparable. • Chlorophyll content in the plants was correlated with QAS concentration in the soil. • POD activity increased in plants cultivated in soil with high QAS content. - Abstract: This paper discusses the impact of four quaternary ammonium salts (QAS) such as tetraethylammonium tetrafluoroborate [TEA][BF{sub 4}], tetrabutylammonium tetrafluoroborate [TBA][BF{sub 4}], tetrahexylammonium tetrafluoroborate [THA][BF{sub 4}], and tetraoctylammonium tetrafluoroborate [TOA][BF{sub 4}] on the growth and development of spring barley and common radish. Analogous tests were performed with the inorganic salt ammonium tetrafluoroborate [A][BF{sub 4}] for comparison purposes. Results indicated that the phytotoxicity of the QAS applied is dependent on the concentration of the substance and their number of carbon atoms. The most toxic compound was [TBA][BF{sub 4}], causing the greatest drop in fresh weight of both study plants, similar to the phytotoxic effects of [A][BF{sub 4}]. All the tested compounds caused oxidative stress in spring barley and common radish seedlings due to a drop in the chlorophyll content. Stress was also observed in plants, which was indicated by the increased level of ROS (reactive oxygen species) such as H{sub 2}O{sub 2} and lipid peroxidation of MDA (malondialdehyde). Due to the stress, both plants displayed changes in the activity of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). Based on the results of the study, it was concluded that changes in chlorophyll levels and peroxidase activity are the best biomarkers to determine oxidative stress in plants.

  17. Engineered nanomaterial-mediated changes in the metabolism of terrestrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Hatami, Mehrnaz, E-mail: m-hatami@araku.ac.ir [Department of Medicinal Plants, Faculty of Agriculture and Natural Resources, Arak University, 38156-8-8349 Arak (Iran, Islamic Republic of); Kariman, Khalil [School of Earth and Environment M004, The University of Western Australia, Crawley, WA 6009 (Australia); Ghorbanpour, Mansour, E-mail: m-ghorbanpour@araku.ac.ir [Department of Medicinal Plants, Faculty of Agriculture and Natural Resources, Arak University, 38156-8-8349 Arak (Iran, Islamic Republic of)

    2016-11-15

    Engineered nanomaterials (ENMs) possess remarkable physicochemical characteristics suitable for different applications in medicine, pharmaceuticals, biotechnology, energy, cosmetics and electronics. Because of their ultrafine size and high surface reactivity, ENMs can enter plant cells and interact with intracellular structures and metabolic pathways which may produce toxicity or promote plant growth and development by diverse mechanisms. Depending on their type and concentration, ENMs can have positive or negative effects on photosynthesis, photochemical fluorescence and quantum yield as well as photosynthetic pigments status of the plants. Some studies have shown that ENMs can improve photosynthetic efficiency via increasing chlorophyll content and light absorption and also broadening the spectrum of captured light, suggesting that photosynthesis can be nano-engineered for harnessing more solar energy. Both up- and down-regulation of primary metabolites such as proteins and carbohydrates have been observed following exposure of plants to various ENMs. The potential capacity of ENMs for changing the rate of primary metabolites lies in their close relationship with activation and biosynthesis of the key enzymes. Several classes of secondary metabolites such as phenolics, flavonoids, and alkaloids have been shown to be induced (mostly accompanied by stress-related factors) in plants exposed to different ENMs, highlighting their great potential as elicitors to enhance both quantity and quality of biologically active secondary metabolites. Considering reports on both positive and negative effects of ENMs on plant metabolism, in-depth studies are warranted to figure out the most appropriate ENMs (type, size and optimal concentration) in order to achieve the desirable effect on specific metabolites in a given plant species. In this review, we summarize the studies performed on the impacts of ENMs on biosynthesis of plant primary and secondary metabolites and mention the

  18. Engineered nanomaterial-mediated changes in the metabolism of terrestrial plants

    International Nuclear Information System (INIS)

    Hatami, Mehrnaz; Kariman, Khalil; Ghorbanpour, Mansour

    2016-01-01

    Engineered nanomaterials (ENMs) possess remarkable physicochemical characteristics suitable for different applications in medicine, pharmaceuticals, biotechnology, energy, cosmetics and electronics. Because of their ultrafine size and high surface reactivity, ENMs can enter plant cells and interact with intracellular structures and metabolic pathways which may produce toxicity or promote plant growth and development by diverse mechanisms. Depending on their type and concentration, ENMs can have positive or negative effects on photosynthesis, photochemical fluorescence and quantum yield as well as photosynthetic pigments status of the plants. Some studies have shown that ENMs can improve photosynthetic efficiency via increasing chlorophyll content and light absorption and also broadening the spectrum of captured light, suggesting that photosynthesis can be nano-engineered for harnessing more solar energy. Both up- and down-regulation of primary metabolites such as proteins and carbohydrates have been observed following exposure of plants to various ENMs. The potential capacity of ENMs for changing the rate of primary metabolites lies in their close relationship with activation and biosynthesis of the key enzymes. Several classes of secondary metabolites such as phenolics, flavonoids, and alkaloids have been shown to be induced (mostly accompanied by stress-related factors) in plants exposed to different ENMs, highlighting their great potential as elicitors to enhance both quantity and quality of biologically active secondary metabolites. Considering reports on both positive and negative effects of ENMs on plant metabolism, in-depth studies are warranted to figure out the most appropriate ENMs (type, size and optimal concentration) in order to achieve the desirable effect on specific metabolites in a given plant species. In this review, we summarize the studies performed on the impacts of ENMs on biosynthesis of plant primary and secondary metabolites and mention the

  19. Radioactive pollution from Fukushima Daiichi nuclear power plant in the terrestrial environment.

    Science.gov (United States)

    Tazoe, H; Hosoda, M; Sorimachi, A; Nakata, A; Yoshida, M A; Tokonami, S; Yamada, M

    2012-11-01

    Major contaminants from venting and hydrogen explosions at the Fukushima Daiichi nuclear reactors between 12 and 15 March 2011 were transported northwestward and deposited on soil and plants via precipitation. Surface soils and plant leaves were sampled at 64 sites in the Fukushima Prefecture. The highest concentrations of (134)Cs (84.4 kBq kg(-1)) and (137)Cs (82.0 kBq kg(-1)) in surface soils were observed at Nagadoro in Iidate village located 32 km northwest from the Fukushima Daiichi nuclear power plant. Furthermore, (131)I, (129)Te, (129 m)Te, (110 m)Ag and (140)La were detected in the same samples. Outer surface of plant leaves, such as bamboo, cabbage and grasses were highly contaminated at the high-dose rate areas of Tsushima and Minami-Tsushima in Namie town. Mugwort leaves that grew after the pollution event had extremely low concentration of radionuclides; however, the plant/soil radiocaesium ratio was 0.023 ± 0.006. It is anticipated that decomposition of fallen leaves will promote recycling of radionuclides in the environment.

  20. Effects of terrestrial runoff on the coral communities in Santiago Bay, Colima, Mexican Pacific Coast.

    Science.gov (United States)

    Liñán-Cabello, Marco Agustín; Olivos-Ortiz, Aramis; Quijano-Scheggia, Sonia; Muñiz Anguiano, Daniela; Reséndiz-Flores, María Luisa; Ortega-Ortíz, Christian D

    2016-09-01

    Coral reef ecosystems are under stress of different origins, from factors including sedimentation, fragmentation, overfishing, and tourism, depending on their geographical location, depth, and proximity to recreation areas. In this study of Juluapan Lagoon, we examined the relationship between various water-quality attributes and the status indicators of the coral community at La Boquita reef. During 2011 (12 months of sampling), six monitoring stations in the Juluapan lagoon were established in order to observe the gradient of the distribution of the physicochemical parameters: three stations on the upper part, or BI, (S4 to S6) and three more in the lower part, or BII, (S1 to S3). A control station (CS) was located in the coral reef close to the lagoon channel, and where dissolved inorganic nutrients and cellular carbon content were determined. Additionally, we considered the monitoring of three of the eight largest coral structures/headlands of this community: the first was the station closest to the channel communicating with Juluapan lagoon (C1), the second was in the intermediate region with respect to that lagoon (C2), and the third was farthest from the channel (C3). Three line intercept transects (LIT) 30 m in length and perpendicular to the coast provenance were established in each station, and the parameters indicative of the status of corals were evaluated in an area of 60 m2 on each transect (180 m2 by the station). Turbidity, evidence of fishing, signs of settling, algal coverage, abundance of fish, rate of sediment, and coral health records (as for CoralWach chart) were determined in situ and from digital photographs and videos. Considering various community status indicators used in the reef area, we could recognize a state of general deterioration, which was reflected in the loss of 17 % of coral coverage. The main anthropogenic disturbances in adjacent areas to La Boquita reef included wastewater discharges into the lagoon, tourist developments in

  1. Absence of Hg transpiration by shoot after Hg uptake by roots of six terrestrial plant species

    International Nuclear Information System (INIS)

    Greger, Maria; Wang Yaodong; Neuschuetz, Clara

    2005-01-01

    In this paper we investigated if, and to what extent, six different plant species accumulate, translocate and emit mercury (Hg) into the air. The Hg uptake by roots, distribution of Hg to the shoot and release of Hg via shoots of garden pea, spring wheat, sugar beet, oil-seed rape, white clover and willow were investigated in a transpiration chamber. The airborne Hg was trapped in a Hopcalite trap or a gold trap. Traps and plant materials were analysed for content of Hg by CVAAS. The results show that all plant species were able to take up Hg to a large extent from a nutrient solution containing 200 μg L -1 Hg. However, the Hg translocation to the shoot was low (0.17-2.5%) and the Hg that reached the leaves was trapped and no release of the absorbed Hg to the air was detected. - Mercury translocation to shoots was low

  2. Studies on Terrestrial Herbaceous Plants Tolerance to Excess Heavy Metals: Methodological Approach

    Directory of Open Access Journals (Sweden)

    Andon Vassilev

    2010-12-01

    Full Text Available Plant tolerance to heavy metals is а scientific issue attracting significantattention due to the possible use of tolerant plants for phytoremediation purposes as wellas due to the fact that the molecular mechanisms of this phenomenon are not clearenough. Despite of the increasing volume of research on the problem, the availableinformation in many cases is incomplete and/or difficult to compare with other studiesbecause of the significant differences in the experimental designs, range of used metalconcentrations, exposure time, etc. In this review-paper both the advantages andlimitations of the used experimental designs as well as the methods for evaluation ofheavy metal tolerance are briefly discussed.

  3. Genetic diversity within a dominant plant outweighs plant species diversity in structuring an arthropod community.

    Science.gov (United States)

    Crawford, Kerri M; Rudgers, Jennifer A

    2013-05-01

    Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species

  4. Resistance of Terrestrial Microbial Communities to Impack of Physical Conditinos of Subsurface Layers of Martian Regolith

    Science.gov (United States)

    Cheptsov, V. S.; Vorobyova, E. A.

    2017-05-01

    Currently, astrobiology is focused on Mars as one of the most perspective objects in the Solar System to search for microbial life. It was assumed that the putative biosphere of Mars could be cryopreserved and had been stored for billions of years in anabiotic state like microbial communities of Arctic and Antarctic permafrost deposits have been preserved till now for millions of years. In this case microbial cells should be not able to repair the damages or these processes have to be significantly depressed, and the main factor causing cell's death should be ionizing radiation. In a series of experiments we simulated the effects of combination of physical factors known as characteristics of the Martian regolith (and close to the space environment) on the natural microbial communities inhabiting xerophytic harsh habitats with extreme temperature conditions: polar permafrost and desert soils. The aim of the study was to examine the cumulative effect of factors (gamma radiation, low temperature, low pressure) to assess the possibility of metabolic reactions, and to find limits of the viability of natural microbial communities after exposure to the given conditions. It was found that microbial biomarkers could be reliably detected in soil samples after radiation dose accumulation up to 1 MGy (not further investigated) in combination with exposure to low temperature and low pressure. Resistance to extremely high doses of radiation in simulated conditions proves that if there was an Earth-like biosphere on the early Mars microorganisms could survive in the surface or subsurface layers of the Martian regolith for more than tens of millions of years after climate change. The study gives also some new grounds for the approval of transfer of viable microorganisms in space.

  5. Biogeochemical Indicators in High- and Low-Arctic Marine and Terrestrial Avian Community Changes: Comparative Isotopic (13C, 15N, and 34S) Studies in Alaska and Greenland

    Science.gov (United States)

    Causey, D.; Bargmann, N. A.; Burnham, K. K.; Burnham, J. L.; Padula, V. M.; Johnson, J. A.; Welker, J. M.

    2011-12-01

    Understanding the complex dynamics of environmental change in northern latitudes is of paramount importance today, given documented rapid shifts in sea ice, plant phenology, temperatures, deglaciation, and habitat fidelity. This knowledge is particularly critical for Arctic avian communities, which are integral components by which biological teleconnections are maintained between the mid and northern latitudes. Furthermore, Arctic birds are fundamental to Native subsistence lifestyles and a focus for conservation activities. Avian communities of marine and terrestrial Arctic environments represent a broad spectrum of trophic levels, from herbivores (eg., geese Chen spp.), planktivores (eg., auklets Aethia spp.), and insectivores (eg., passerines: Wheatears Oenanthe spp., Longspurs Calcarius spp.), to predators of marine invertebrates (eg., eiders Somateria spp.), nearshore and offshore fish (eg., cormorants Phalacrocorax spp, puffins Fratercula spp.), even other bird species (eg., gulls Larus spp., falcons Peregrinus spp.). This diversity of trophic interconnections is an integral factor in the dynamics of Arctic ecosystem ecology, and they are key indicators for the strength and trajectories of change. We are especially interested in their feeding ecology, using stable isotope-diet relations to examine historical diets and to predict future feeding ecology by this range of species. Since 2009, we have been studying the foodweb ecology using stable isotopes (δ13C, δ15N, δ34S) of contemporaneous coastal and marine bird communities in High Arctic (Northwest Greenland) and Low Arctic (western Aleutian Islands, AK). We are quantifying the isotopic values of blood, organ tissues, and feathers, and have carried out comparisons between native and lipid-extracted samples. Although geographically distant, these communities comprise similar taxonomic and ecological congeners, including several species common to both (eg., Common Eider, Black-legged Kittiwake, Northern

  6. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish

    DEFF Research Database (Denmark)

    Dahl, Tais Wittchen; Hammarlund, Emma; Anbar, Ariel D.

    2010-01-01

    after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon...

  7. Invasive alien plants in the terrestrial ecosystems of Natal, South Africa

    CSIR Research Space (South Africa)

    Macdonald, IAW

    1985-01-01

    Full Text Available This report consists of two types of chapters. Most of the chapters are short syntheses of particular aspects of the alien plant problem in Natal, written by groups of participants during the workshop meeting. They are brief accounts of the state...

  8. Plant reproduction is altered by simulated herbicide drift to constructed plant communities

    Science.gov (United States)

    Herbicide drift may have unintended impacts on native vegetation, adversely affecting structure and function of plant communities. However, these potential effects have been rarely studied or quantified. To determine potential ecological effects of herbicide drift, we construct...

  9. Management of plant communities on set-aside land and its effects on earthworm communities

    Czech Academy of Sciences Publication Activity Database

    Gormsen, D.; Hedlund, K.; Korthals, G. W.; Mortimer, S. R.; Pižl, Václav; Šmilauerová, M.; Sugg, E.

    2004-01-01

    Roč. 40, 3-4 (2004), s. 123-128 ISSN 1164-5563 Grant - others:Evropská unie(XE) ENV4-CT95-0002 Keywords : earthworm community * plant community * land use Subject RIV: EH - Ecology, Behaviour Impact factor: 0.776, year: 2004

  10. Introduced Terrestrial Species (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted future potential distributions of terrestrial plants, animals, and pathogens non-native to the Middle-Atlantic region. These data are...

  11. 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

  12. Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

    Science.gov (United States)

    Hauptmann, Aviaja L.; Markussen, Thor N.; Stibal, Marek; Olsen, Nikoline S.; Elberling, Bo; Bælum, Jacob; Sicheritz-Pontén, Thomas; Jacobsen, Carsten S.

    2016-01-01

    Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns. PMID:27708629

  13. Upstream freshwater and terrestrial sources are differentially reflected in the bacterial community structure along a small Arctic river and its estuary

    Directory of Open Access Journals (Sweden)

    Aviaja Lyberth Hauptmann

    2016-09-01

    Full Text Available Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N. Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns.

  14. Negative Plant-Soil Feedback and Positive Species Interaction in a Herbaceous Plant Community

    NARCIS (Netherlands)

    Bonanomi, G.; Rietkerk, M.; Dekker, S.C.; Mazzoleni, S.

    2005-01-01

    Increasing evidence shows that facilitative interaction and negative plant¿soil feedback are driving factors of plant population dynamics and community processes. We studied the intensity and the relative impact of negative feedback on clonal growth and seed germination of Scirpus holoschoenus, a

  15. Chain-Length Distribution and Hydrogen Isotopic Fraction of n-alkyl Lipids in Aquatic and Terrestrial Plants: Implications for Paleoclimate Reconstructions

    Science.gov (United States)

    Gao, L.; Littlejohn, S.; Hou, J.; Toney, J.; Huang, Y.

    2008-12-01

    Recent studies demonstrate that in lacustrine sediments, aquatic plant lipids (e.g., C22-fatty acid) record lake water D/H ratio variation, while long-chain fatty acids (C26-C32, major components of terrestrial plant leaf waxes), record D/H ratios of precipitation (especially in arid regions). However, there are insufficient literature data for the distribution and hydrogen isotopic fractionation of n-alkyl lipids in aquatic and terrestrial plants. In this study, we determined the chain-length distributions and D/H ratios of n-alkyl lipids from 17 aquatic plant species (9 emergent, 4 floating and 4 submerge species) and 13 terrestrial plant species (7 grasses and 6 trees) from Blood Pond, Massachusetts. Our results are consistent with previous studies and provide a solid basis for the paleoclimatic reconstruction using D/H ratios of aquatic and terrestrial plant biomarkers. In addition, systematic hydrogen isotopic analyses on leaf waxes, leaf, stem and soil waters from trees and grasses significantly advance our understanding of our previously observed large D/H ratio difference between tree and grass leaf waxes. Our data indicate that the observed difference is not due to differences in leaf water D/H ratios. In comparison with grasses, trees use greater proportion of D-enriched residual or stored carbohydrates (as opposed to current photosynthetic carbohydrates) for leaf wax biosynthesis, resulting in higher leaf wax D/H ratios. The residual carbohydrates are enriched in deuterium because of the preferential consumption of light-hydrogen substrates during plant metabolism.

  16. Identifying the plant-associated microbiome across aquatic and terrestrial environments: the effects of amplification method on taxa discovery

    Energy Technology Data Exchange (ETDEWEB)

    Jackrel, Sara L. [Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street Chicago IL 60637 USA; Owens, Sarah M. [Biosciences Division, Argonne National Laboratory, 9700 S. Cass Avenue Lemont IL 60439 USA; Gilbert, Jack A. [Biosciences Division, Argonne National Laboratory, 9700 S. Cass Avenue Lemont IL 60439 USA; The Microbiome Center, Department of Surgery, The University of Chicago, 5841 S Maryland Ave Chicago IL 60637 USA; Pfister, Catherine A. [Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street Chicago IL 60637 USA

    2017-01-25

    Plants in terrestrial and aquatic environments contain a diverse microbiome. Yet, the chloroplast and mitochondria organelles of the plant eukaryotic cell originate from free-living cyanobacteria and Rickettsiales. This represents a challenge for sequencing the plant microbiome with universal primers, as ~99% of 16S rRNA sequences may consist of chloroplast and mitochondrial sequences. Peptide nucleic acid clamps offer a potential solution by blocking amplification of host-associated sequences. We assessed the efficacy of chloroplast and mitochondria-blocking clamps against a range of microbial taxa from soil, freshwater and marine environments. While we found that the mitochondrial blocking clamps appear to be a robust method for assessing animal-associated microbiota, Proteobacterial 16S rRNA binds to the chloroplast-blocking clamp, resulting in a strong sequencing bias against this group. We attribute this bias to a conserved 14-bp sequence in the Proteobacteria that matches the 17-bp chloroplast-blocking clamp sequence. By scanning the Greengenes database, we provide a reference list of nearly 1500 taxa that contain this 14-bp sequence, including 48 families such as the Rhodobacteraceae, Phyllobacteriaceae, Rhizobiaceae, Kiloniellaceae and Caulobacteraceae. To determine where these taxa are found in nature, we mapped this taxa reference list against the Earth Microbiome Project database. These taxa are abundant in a variety of environments, particularly aquatic and semiaquatic freshwater and marine habitats. To facilitate informed decisions on effective use of organelle-blocking clamps, we provide a searchable database of microbial taxa in the Greengenes and Silva databases matching various n-mer oligonucleotides of each PNA sequence.

  17. Plant Communities Suitable for Green Roofs in Arid Regions

    Directory of Open Access Journals (Sweden)

    Rachel Gioannini

    2018-05-01

    Full Text Available In extensive green roof settings, plant communities can be more robust than monocultures. In addition, native plants might be hardier and more ecologically sound choices than non-native plants in green roof systems. The objectives of this research were to (1 compare the performance of plant communities with that of monocultures and (2 compare the growth of natives to non-natives in a simulated green roof setting. We conducted a two-year experiment at an outdoor site in a desert environment using four plant morphological types (groundcover, forb, succulent and grass. Native plants selected were Chrysactinia mexicana, Melampodium leucanthum, Euphorbia antisyphilitica, and Nassella tenuissima, and non-natives were Delosperma nubigenum, Stachys byzantina, Sedum kamtschiaticum and Festuca glauca. Plants were assigned randomly to either monoculture or community and grown in 1 m × 1 m custom-built trays filled with 15 cm of a proprietary blend of 50/20/30 lightweight aggregate/sand/compost (by volume. Native forb, Melampodium, in community had greater coverage for four of the five measurements in the first year over native forb in monoculture and non-native forb regardless of setting. Native forb coverage was also greater than non-native forb for three of the four measurements in year 2, regardless of setting. Coverage of native grass was significantly greater than non-native grasses throughout the experiment. Coverage was also greater for eight of nine measurements for native succulent over non-natives succulent. However, non-native groundcover coverage was significantly greater than native groundcover for seven of nine measurements. On 1 November 2016, relative water content (RWC for succulents (p = 0.0424 was greatest for native Euphorbia in monoculture at 88%. Native Euphorbia also had greater RWC than non-native Sedum on 4 April 2017 (78% and 4 July 2017 (80%. However, non-native Sedum had greater root length (6548 cm, root dry weight (12.1 g

  18. Summary of plutonium terrestrial research studies in the vicinity of a nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Corey, J.C.; Boni, A.L.; Andriano, D.C.; Pinder, J.F.; McLeod, K.W.

    1978-01-01

    This paper reports plutonium concentrations of wheat, soybeans, and corn grown (a) on a field adjacent to one of the nuclear reprocessing facilities at the Savannah River Plant (SRP), (b) in a glasshouse, and (c) offsite. The crops on SRP were grown on a field that has been receiving both fallout plutonium and plutonium emitted at low chronic levels from an air exhaust stack since 1955. The crops grown in the glasshouse were raised on soil from the onsite agricultural field. The offsite field has received only fallout plutonium. The crop data indicate that the dose to an individual from ingesting grain grown on the field, although higher than from ingesting grain grown offsite, is still small (the 70-year dose-to-bone from eating 2 X 10 5 g (440 lb) of wheat in a year would be less than one mrem). Crop data from the field and the glasshouse experiment indicate that less than 10% of the total contamination of field-grown crops adjacent to a reprocessing facility was contributed by root uptake, the remainder by deposition on the plant surfaces. The plutonium content of the grain was generally 10 to 100 times less than that of the vegetation, again suggesting that deposition from stack emissions vegetation, again suggesting that deposition from stack emissions on the vegetation increased the plutonium content; whereas the grain, particularly corn and soybeans, was protected by thehusk or pod and contained principally plutonium from the root uptake pathway

  19. Toxicological benchmarks for screening potential contaminants of concern for effects on terrestrial plants: 1994 revision

    International Nuclear Information System (INIS)

    Will, M.E.; Suter, G.W. II.

    1994-09-01

    One of the initial stages in ecological risk assessment for hazardous waste sites is screening contaminants to determine which of them are worthy of further consideration as contaminants of potential concern. This process is termed contaminant screening. It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to plants. This report presents a standard method for deriving benchmarks for this purpose (phytotoxicity benchmarks), a set of data concerning effects of chemicals in soil or soil solution on plants, and a set of phytotoxicity benchmarks for 38 chemicals potentially associated with United States Department of Energy (DOE) sites. In addition, background information on the phytotoxicity and occurrence of the chemicals in soils is presented, and literature describing the experiments from which data were drawn for benchmark derivation is reviewed. Chemicals that are found in soil at concentrations exceeding both the phytotoxicity benchmark and the background concentration for the soil type should be considered contaminants of potential concern

  20. Toxicological benchmarks for screening potential contaminants of concern for effects on terrestrial plants: 1994 revision

    Energy Technology Data Exchange (ETDEWEB)

    Will, M.E.; Suter, G.W. II

    1994-09-01

    One of the initial stages in ecological risk assessment for hazardous waste sites is screening contaminants to determine which of them are worthy of further consideration as contaminants of potential concern. This process is termed contaminant screening. It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to plants. This report presents a standard method for deriving benchmarks for this purpose (phytotoxicity benchmarks), a set of data concerning effects of chemicals in soil or soil solution on plants, and a set of phytotoxicity benchmarks for 38 chemicals potentially associated with United States Department of Energy (DOE) sites. In addition, background information on the phytotoxicity and occurrence of the chemicals in soils is presented, and literature describing the experiments from which data were drawn for benchmark derivation is reviewed. Chemicals that are found in soil at concentrations exceeding both the phytotoxicity benchmark and the background concentration for the soil type should be considered contaminants of potential concern.

  1. Ants swimming in pitcher plants: kinematics of aquatic and terrestrial locomotion in Camponotus schmitzi.

    Science.gov (United States)

    Bohn, Holger Florian; Thornham, Daniel George; Federle, Walter

    2012-06-01

    Camponotus schmitzi ants live in symbiosis with the Bornean pitcher plant Nepenthes bicalcarata. Unique among ants, the workers regularly dive and swim in the pitcher's digestive fluid to forage for food. High-speed motion analysis revealed that C. schmitzi ants swim at the surface with all legs submerged, with an alternating tripod pattern. Compared to running, swimming involves lower stepping frequencies and larger phase delays within the legs of each tripod. Swimming ants move front and middle legs faster and keep them more extended during the power stroke than during the return stroke. Thrust estimates calculated from three-dimensional leg kinematics using a blade-element approach confirmed that forward propulsion is mainly achieved by the front and middle legs. The hind legs move much less, suggesting that they mainly serve for steering. Experiments with tethered C. schmitzi ants showed that characteristic swimming movements can be triggered by submersion in water. This reaction was absent in another Camponotus species investigated. Our study demonstrates how insects can use the same locomotory system and similar gait patterns for moving on land and in water. We discuss insect adaptations for aquatic/amphibious lifestyles and the special adaptations of C. schmitzi to living on an insect-trapping pitcher plant.

  2. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Terrestrial Plants

    Energy Technology Data Exchange (ETDEWEB)

    Suter, G.W. II

    1993-01-01

    One of the initial stages in ecological risk assessment for hazardous waste sites is screening contaminants to determine which of them are worthy of further consideration as contaminants of potential concern. This process is termed contaminant screening. It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to plants. This report presents a standard method for deriving benchmarks for this purpose (phytotoxicity benchmarks), a set of data concerning effects of chemicals in soil or soil solution on plants, and a set of phytotoxicity benchmarks for 38 chemicals potentially associated with United States Department of Energy (DOE) sites. In addition, background information on the phytotoxicity and occurrence of the chemicals in soils is presented, and literature describing the experiments from which data were drawn for benchmark derivation is reviewed. Chemicals that are found in soil at concentrations exceeding both the phytotoxicity benchmark and the background concentration for the soil type should be considered contaminants of potential concern.

  3. Space and Terrestrial Power System Integration Optimization Code BRMAPS for Gas Turbine Space Power Plants With Nuclear Reactor Heat Sources

    Science.gov (United States)

    Juhasz, Albert J.

    2007-01-01

    In view of the difficult times the US and global economies are experiencing today, funds for the development of advanced fission reactors nuclear power systems for space propulsion and planetary surface applications are currently not available. However, according to the Energy Policy Act of 2005 the U.S. needs to invest in developing fission reactor technology for ground based terrestrial power plants. Such plants would make a significant contribution toward drastic reduction of worldwide greenhouse gas emissions and associated global warming. To accomplish this goal the Next Generation Nuclear Plant Project (NGNP) has been established by DOE under the Generation IV Nuclear Systems Initiative. Idaho National Laboratory (INL) was designated as the lead in the development of VHTR (Very High Temperature Reactor) and HTGR (High Temperature Gas Reactor) technology to be integrated with MMW (multi-megawatt) helium gas turbine driven electric power AC generators. However, the advantages of transmitting power in high voltage DC form over large distances are also explored in the seminar lecture series. As an attractive alternate heat source the Liquid Fluoride Reactor (LFR), pioneered at ORNL (Oak Ridge National Laboratory) in the mid 1960's, would offer much higher energy yields than current nuclear plants by using an inherently safe energy conversion scheme based on the Thorium --> U233 fuel cycle and a fission process with a negative temperature coefficient of reactivity. The power plants are to be sized to meet electric power demand during peak periods and also for providing thermal energy for hydrogen (H2) production during "off peak" periods. This approach will both supply electric power by using environmentally clean nuclear heat which does not generate green house gases, and also provide a clean fuel H2 for the future, when, due to increased global demand and the decline in discovering new deposits, our supply of liquid fossil fuels will have been used up. This is

  4. Plant Community Diversity After Herbicide Control of Spotted Knapweed

    OpenAIRE

    United States Department of Agriculture, Forest Service

    1992-01-01

    Herbicides were applied to four west-central Montana sites with light to moderate spotted knapweed (Centaurea maculosa Lam.) infestations. Althought knapweed suppression was high, 2 years after the spraying the communities were not converted to grass monocultures. No large declines in plant diversity were caused by the herbicides, and small depressions were probably transitory. By the third year, diversity had increased.

  5. Vascular plant diversity and community Structure of nandi forests ...

    African Journals Online (AJOL)

    Abundance data of species was used for species diversity, similarity, species richness estimation and plant community analysis. PC-ORD, CANOCO and EstimateS were used to analyze the data. A total of 321 species ... Keywords: floristic composition, ordination, rarefaction, species accumulation, species richness.

  6. Functional diversity in plant communities: Theory and analysis ...

    African Journals Online (AJOL)

    Plant functional diversity in community has become a key point in ecology studies recently. The development of species functional diversity was reviewed in the present work. Based on the former original research papers and reviews, we discussed the concept and connotation and put forward a new definition of functional ...

  7. A baseline classification of riparian woodland plant communities in ...

    African Journals Online (AJOL)

    The plots were placed along a gradient from the main water body to the drier fringe of the riparian zone. Plant species present in each plot were recorded with their estimated percentage cover using the Braun–Blanquet cover abundance scale. Hierarchical cluster analysis was used to determine vegetation communities.

  8. Plant community development is affected by nutrients and soil biota

    NARCIS (Netherlands)

    De Deyn, G.B.; Raaijmakers, C.E.; Van der Putten, W.H.

    2004-01-01

    1 Plant community development depends to a great extent on the availability of soil nutrients, but recent studies underline the role of symbiotic, herbivorous and pathogenic soil biota. We tested for interactions between these biotic and abiotic factors by studying the effects of additional

  9. Andean shrublands of Moquegua, South Peru: Prepuna plant communities

    NARCIS (Netherlands)

    Montesinos, D.B.; Cleef, A.M.; Sykora, K.V.

    2012-01-01

    A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes

  10. Terrestrial bryophytes as indicators of fluoride emission from a phosphorus plant, Long Harbour, Newfoundland, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, B.A.; Thompson, L.K.; Sidhu, S.S.

    1979-01-01

    A study of the effects of fluoride emissions (HF, SiF/sub 4/) on certain species of bryophytes was carried out in the vicinity of an industrial palnt producing elemental phosphorus at Long Harbour, Nfld. Damage symptoms varied from mild phyllid chlorosis (yellowing) to severe browning of up to 95% of the phyllids. Polytrichum commune Hedw. was the main bryophyte species used in the survey. Random collections from 45 sample sites were analysed for total fluoride. The fluoride concentrations in phyllid tissue ranged from a high of 6066 ppm (dry weight) at a distance of 1 km northeast of the emission source to 44 ppm (dry weight) 11.7 km northeast of the emission source in the direction of the prevailing wind. Control samples were obtained from similar sites in areas far removed from the industrial plant and contained, on average, 11.3 ppm (dry weight). The concentration of fluoride in the bryophyte phyllid tissue was inversely correlated with distance from the emission source, in the direction of the prevailing wind. The severity of acropetal scorching was found to be correlated with the concentration of fluoride in the bryophyte phyllid tissue, and in addition, samples high in fluoride had fewer sporophytes. Fluoride concentrations in bryophyte tissue are compared with concentrations of fluoride in the needles of balsam fir, Abies Balsamea I., in four damage zones, and also with available and total fluoride in soil humus and concentrations of fluoride in air. The total area affected by fluoride emissions was increased using bryophytes as the pollution indicator species, especially in areas far from the industrial plant.

  11. The nuclear power plant and the host community

    International Nuclear Information System (INIS)

    Olsson, G.

    1978-01-01

    A councillor from a small Swedish community (Kaevlinge) in the vicinity of the Barsebaeck nuclear power plant describes the effects which the plant has had on neighbouring communities. The effect on the labour market has been small at Kaevlinge, both during routine operation and construction phases. This is however, a fairly densely populated area with a population of half a million in a radius of 30 km. The situation is different at Oskarshamn or Oesthammar. Neither has there been any special economic benefit, due to Swedish taxation laws. There has been little local anxiety due to the proximity of the nuclear power plant. Certain local planning problems have been caused by restricted zones and power cables. Cooperation between the local authorities and the utility has been good. (JIW)

  12. Investigating the Effect of Livestock Grazing and Associated Plant Community Shifts on Carbon and Nutrient Cycling in Alberta, Canada

    Science.gov (United States)

    Hewins, D. B.; Chuan, S.; Stolnikova, E.; Bork, E. W.; Carlyle, C. N.; Chang, S. X.

    2015-12-01

    Grassland ecosystems are ubiquitous across the globe covering an estimated 40 % of Earth's terrestrial landmass. These ecosystems are widely valued for providing forage for domestic livestock and a suite of important ecosystem goods and services including carbon (C) storage. Despite storing more than 30 % of soil C globally, the effect of both livestock grazing and the associated change in plant community structure in response to grazing on C and nutrient cycling remains uncertain. To gain a quantitative understanding of the direct and indirect effects of livestock grazing on C and nutrient cycling, we established study sites at 15 existing site localities with paired long-term grazing (ca. 30 y) and non-grazed treatments (totaling 30 unique plant communities). Our sites were distributed widely across Alberta in three distinct grassland bioclimatic zones allowing us to make comparisons across the broad range of climate variability typical of western Canadian grasslands. In each plant community we decomposed 5 common plant species that are known to increase or decrease in response to grazing pressure, a unique plant community sample, and a cellulose paper control. We measured mass loss, initial lignin, C and N concentrations at 0, 1, 3, 6 and 12 months of field incubation. In addition we assayed hydrolytic and oxidative extracellular enzymes associated with for C (n= 5 hydrolytic; phenoloxidase and peroxidase) and nutrients (i.e. N and P; n=1 ea.) cycling from each litter sample at each collection. Our results suggest that by changing the plant community structure, grazing can affect rates of decomposition and associated biogeochemical cycling by changing plant species and associated litter inputs. Moreover, measures of microbial function are controlled by site-specific conditions (e.g. temperature and precipitation), litter chemistry over the course of our incubation.

  13. Water and Nitrogen Limitations of Ecosystem Processes Across Three Dryland Plant Communities

    Science.gov (United States)

    Beltz, C.; Lauenroth, W. K.; Burke, I. C.

    2017-12-01

    The availability of water and nitrogen (N) play a major role in controlling the distribution of ecosystem types and the rates of ecosystem processes across the globe. Both these resources are being altered by human activity. Anthropogenic fixation of N has increased inputs into the biosphere from 0.5 kg N ha-1 yr-1 to upwards of 10 kg N ha-1 yr-1, while the amount and seasonality of precipitation are expected to continue to change. Within dryland environments, the relationships between increasingly available N and ecosystem processes are especially complex due to dryland's characteristic strong limitation by low and highly variable precipitation. Other experiments have shown that this interplay between N and water can cause temporally complex co-limitation and spatially complex responses with variable effects on ecosystems, such as those to net primary productivity, soil respiration, and plant community composition. Research spanning multiple dryland plant communities is critical for generalizing findings to the 40% of the Earth's terrestrial surface covered in dryland ecosystems. Given IPCC projections in which both N availability and precipitation are altered, examining their interactive effect across multiple plant communities is critical to increasing our understanding of the limitations to ecosystem process in drylands. We are studying a gradient of three plant communities representing a C4 grassland (shortgrass steppe), a C3/C4 grassland (mixed grass prairie), and a shrub-dominated ecosystem with C3 and C4 grasses (sagebrush steppe). We added two levels of N (10 kg N ha-1 and 100 kg N ha-1) and increased summer monthly precipitation by 20%. Sites responded differently to treatments, with the scale of effect varying by treatment. The high-level nitrogen increased soil N availability and soil respiration, while decreasing soil carbon in the labile pool in the upper soil layers. These results will allow for better understanding of increased N in combination with

  14. Effects of Trampling Limitation on Coastal Dune Plant Communities

    Science.gov (United States)

    Santoro, Riccardo; Jucker, Tommaso; Prisco, Irene; Carboni, Marta; Battisti, Corrado; Acosta, Alicia T. R.

    2012-03-01

    Sandy coastlines are sensitive ecosystems where human activities can have considerable negative impacts. In particular, trampling by beach visitors is a disturbance that affects dune vegetation both at the species and community level. In this study we assess the effects of the limitation of human trampling on dune vegetation in a coastal protected area of Central Italy. We compare plant species diversity in two recently fenced sectors with that of an unfenced area (and therefore subject to human trampling) using rarefaction curves and a diversity/dominance approach during a two year study period. Our results indicate that limiting human trampling seems to be a key factor in driving changes in the plant diversity of dune systems. In 2007 the regression lines of species abundance as a function of rank showed steep slopes and high Y-intercept values in all sectors, indicating a comparable level of stress and dominance across the entire study site. On the contrary, in 2009 the regression lines of the two fenced sectors clearly diverge from that of the open sector, showing less steep slopes. This change in the slopes of the tendency lines, evidenced by the diversity/dominance diagrams and related to an increase in species diversity, suggests the recovery of plant communities in the two fences between 2007 and 2009. In general, plant communities subject to trampling tended to be poorer in species and less structured, since only dominant and tolerant plant species persisted. Furthermore, limiting trampling appears to have produced positive changes in the dune vegetation assemblage after a period of only two years. These results are encouraging for the management of coastal dune systems. They highlight how a simple and cost-effective management strategy, based on passive recovery conservation measures (i.e., fence building), can be a quick (1-2 years) and effective method for improving and safeguarding the diversity of dune plant communities.

  15. Ethnobotany of dye plants in Dong communities of China.

    Science.gov (United States)

    Liu, Yujing; Ahmed, Selena; Liu, Bo; Guo, Zhiyong; Huang, Weijuan; Wu, Xianjin; Li, Shenghua; Zhou, Jiangju; Lei, Qiyi; Long, Chunlin

    2014-02-19

    Dyes derived from plants have an extensive history of use for coloring food and clothing in Dong communities and other indigenous areas in the uplands of China. In addition to use as coloring agents, Dong communities have historically utilized dye plants for their value for enhancing the nutritive, medicinal and preservative properties of foods. However, the persistence of plant-derived dyes and associated cultural practices and traditional knowledge is threatened with rapid socio-economic change in China. Research is needed to document the ethnobotany of dye plants in indigenous communities towards their conservation and potential commercialization as a sustainable means of supporting local development initiatives. Semi-structured surveys on plants used for coloring agents and associated traditional knowledge were conducted in fifteen Dong villages of Tongdao County in Hunan Province of South Central China during 2011-2012. Transect walks were carried out with key informants identified from semi-structured surveys to collect samples and voucher specimens for each documented plant species for taxonomic identification. Dong households at the study sites utilize the flowers, bark, stems, tubers and roots of 13 plant species from 9 families as dyes to color their customary clothing and food. Out of the documented plants, a total of 7 are used for coloring food, 3 for coloring clothing and 3 for both food and clothing. Documented plants consist of 3 species that yield black pigments, 3 for brownish red/russet pigments, 3 for red pigments, 2 for dark blue pigments and 2 for yellow pigments. In addition to dyes, the plants have multiple uses including medicinal, ornamental, sacrificial, edible, and for timber. The use of dyes derived from plants persists at the study sites for their important role in expressing Dong cultural identity through customary clothing and food. Further research is needed to evaluate the safety of dye plants, their efficacy in enhancing food

  16. Habitat Fragmentation Drives Plant Community Assembly Processes across Life Stages

    Science.gov (United States)

    Hu, Guang; Feeley, Kenneth J.; Yu, Mingjian

    2016-01-01

    Habitat fragmentation is one of the principal causes of biodiversity loss and hence understanding its impacts on community assembly and disassembly is an important topic in ecology. We studied the relationships between fragmentation and community assembly processes in the land-bridge island system of Thousand Island Lake in East China. We focused on the changes in species diversity and phylogenetic diversity that occurred between life stages of woody plants growing on these islands. The observed diversities were compared with the expected diversities from random null models to characterize assembly processes. Regression tree analysis was used to illustrate the relationships between island attributes and community assembly processes. We found that different assembly processes predominate in the seedlings-to-saplings life-stage transition (SS) vs. the saplings-to-trees transition (ST). Island area was the main attribute driving the assembly process in SS. In ST, island isolation was more important. Within a fragmented landscape, the factors driving community assembly processes were found to differ between life stage transitions. Environmental filtering had a strong effect on the seedlings-to-saplings life-stage transition. Habitat isolation and dispersal limitation influenced all plant life stages, but had a weaker effect on communities than area. These findings add to our understanding of the processes driving community assembly and species coexistence in the context of pervasive and widespread habitat loss and fragmentation. PMID:27427960

  17. Toxicity assessment for petroleum-contaminated soil using terrestrial invertebrates and plant bioassays.

    Science.gov (United States)

    Hentati, Olfa; Lachhab, Radhia; Ayadi, Mariem; Ksibi, Mohamed

    2013-04-01

    The assessment of soil quality after a chemical or oil spill and/or remediation effort may be measured by evaluating the toxicity of soil organisms. To enhance our understanding of the soil quality resulting from laboratory and oil field spill remediation, we assessed toxicity levels by using earthworms and springtails testing and plant growth experiments. Total petroleum hydrocarbons (TPH)-contaminated soil samples were collected from an oilfield in Sfax, Tunisia. Two types of bioassays were performed. The first assessed the toxicity of spiked crude oil (API gravity 32) in Organization for Economic Co-operation and Development artificial soil. The second evaluated the habitat function through the avoidance responses of earthworms and springtails and the ability of Avena sativa to grow in TPH-contaminated soils diluted with farmland soil. The EC50 of petroleum-contaminated soil for earthworms was 644 mg of TPH/kg of soil at 14 days, with 67 % of the earthworms dying after 14 days when the TPH content reached 1,000 mg/kg. The average germination rate, calculated 8 days after sowing, varied between 64 and 74 % in low contaminated soils and less than 50 % in highly contaminated soils.

  18. Using an Ongoing Study of Terrestrial Plant Response to Ultraviolet Radiation in Project ALERT

    Science.gov (United States)

    Condon, Estelle; Skiles, J. W.; Seitz, Jeffery C.; Dantoni, Hector L.

    1998-01-01

    The ALERT (Augmented Learning Environment for Renewable Teaching) Project is a cooperative California-based program with two main partners: California State University (CSU) geoscience and education departments and two NASA Centers, the Jet Propulsion Laboratory (JPL) in Pasadena and the Ames Research Center (ARC) in Mountain View. This paper presents an example of how a NASA research effort can be used in the undergraduate classroom. A study, now in the fourth year, subjects test plants to exposures of varying solar ultraviolet (UV) radiation (280 - 340 nm); a full solar UV exposure, a solar UV exposure less about 14% of ambient UV flux, and a UV-blocked regime. This experiment is simple in that only modest amounts of expense are required yet it is elegant since only one variable, UV-flux is involved. The experiment lends itself to teaching several of the Earth Sciences because it uses information from botany, taxonomy, and ecology. Aspects of physics are inherent in the study since portions of the electromagnetic spectrum are studied. Further, since only one of many variables are manipulated, UV flux, the study demonstrates how the scientific method is used in formulating and testing hypotheses. Based on the ALERT experience this summer, this study will be implemented at a CSU campus with the expectation that it will serve as a pedagogical tool and where it will involve students in actual research.

  19. Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant. [Transport of drift-derived chromium in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, F.G.; Hanna, S.R.; Parr, P.D.

    1979-01-01

    The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant.

  20. Phytoremediation: role of terrestrial plants and aquatic macrophytes in the remediation of radionuclides and heavy metal contaminated soil and water.

    Science.gov (United States)

    Sharma, Sunita; Singh, Bikram; Manchanda, V K

    2015-01-01

    significantly raised the amount of heavy metals and radionuclides in it. Also, these activities are continuously increasing the area of the contaminated sites. In this context, an attempt has been made to review different modes of the phytoremediation and various terrestrial and aquatic plants which are being used to remediate the heavy metals and radionuclide-contaminated soil and aquatic systems. Natural and synthetic enhancers, those hasten the process of metal adsorption/absorption by plants, are also discussed. The article includes 216 references.

  1. Plant community resistance to invasion by Bromus species – the roles of community attributes, Bromus Interactions with plant communities, and Bromus traits

    Science.gov (United States)

    Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B

    2016-01-01

    The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.

  2. Plants growing on contaminated and brownfield sites appropriate for use in Organisation for Economic Co-operation and Development terrestrial plant growth test.

    Science.gov (United States)

    Sinnett, Danielle E; Lawrence, Victoria K; Hutchings, Tony R; Hodson, Mark E

    2011-01-01

    The Organisation for Economic Co-operation and Development (OECD) terrestrial plant test is often used for the ecological risk assessment of contaminated land. However, its origins in plant protection product testing mean that the species recommended in the OECD guidelines are unlikely to occur on contaminated land. Six alternative species were tested on contaminated soils from a former Zn smelter and a metal fragmentizer with elevated concentrations of Cd, Cu, Pb, and Zn. The response of the alternative species was compared with that of two species recommended by the OECD: Lolium perenne (perennial ryegrass) and Trifolium pratense (red clover). Urtica dioica (stinging nettle) and Poa annua (annual meadowgrass) had low emergence rates in the control soil and so may be considered unsuitable. Festuca rubra (Chewings fescue), Holcus lanatus (Yorkshire fog), Senecio vulgaris (common groundsel), and Verbascum thapsus (great mullein) offer good alternatives to the OECD species. In particular, H. lanatus and S. vulgaris were more sensitive to the soils with moderate concentrations of Cd, Cu, Pb, and Zn than the OECD species. © 2010 SETAC.

  3. [A phylogenetic analysis of plant communities of Teberda Biosphere Reserve].

    Science.gov (United States)

    Shulakov, A A; Egorov, A V; Onipchenko, V G

    2016-01-01

    Phylogenetic analysis of communities is based on the comparison of distances on the phylogenetic tree between species of a community under study and those distances in random samples taken out of local flora. It makes it possible to determine to what extent a community composition is formed by more closely related species (i.e., "clustered") or, on the opposite, it is more even and includes species that are less related with each other. The first case is usually interpreted as a result of strong influence caused by abiotic factors, due to which species with similar ecology, a priori more closely related, would remain: In the second case, biotic factors, such as competition, may come to the fore and lead to forming a community out of distant clades due to divergence of their ecological niches: The aim of this' study Was Ad explore the phylogenetic structure in communities of the northwestern Caucasus at two spatial scales - the scale of area from 4 to 100 m2 and the smaller scale within a community. The list of local flora of the alpine belt has been composed using the database of geobotanic descriptions carried out in Teberda Biosphere Reserve at true altitudes exceeding.1800 m. It includes 585 species of flowering plants belonging to 57 families. Basal groups of flowering plants are.not represented in the list. At the scale of communities of three classes, namely Thlaspietea rotundifolii - commumties formed on screes and pebbles, Calluno-Ulicetea - alpine meadow, and Mulgedio-Aconitetea subalpine meadows, have not demonstrated significant distinction of phylogenetic structure. At intra level, for alpine meadows the larger share of closely related species. (clustered community) is detected. Significantly clustered happen to be those communities developing on rocks (class Asplenietea trichomanis) and alpine (class Juncetea trifidi). At the same time, alpine lichen proved to have even phylogenetic structure at the small scale. Alpine (class Salicetea herbaceae) that

  4. The plant in between: Analogism and entanglement in an Italian community of anthroposophists

    Directory of Open Access Journals (Sweden)

    Nadia Breda

    2017-01-01

    Full Text Available The article analyses the special relationship with the world of plants developed by anthroposophy from the framework of a new perspective called the “plant turn” (Myers 2015. Anthroposophy (AS is analysed as a peculiar form of Analogism (Descola 2005, historically derived from the philosophy of Rudolf Steiner and subsequently evolved into contemporary AS practices that the author encountered during her fieldwork in a community of North-Eastern Italy. Both Steiner’s texts and the analysis of contemporary practices of AS reveal a relationship with the world of plants that the author reads in light of Ingold’s categories of “interweaving” of the world, the interpenetration of elements, and their ceaseless becoming (Ingold 2011. The result is a representation of the vegetal world involving the whole cosmos, humans and non-humans, terrestrial and celestial, in a cosmic expansion of the relations between beings typical of Analogisms. The practices referring to the vegetal world enacted by anthroposophists are intense, engaging, dialogue-based and provocative in their ability to uproot many elements of naturalism and deal with a contemporary world characterised by ecological crisis.

  5. Taiwan's industrial heavy metal pollution threatens terrestrial biota

    International Nuclear Information System (INIS)

    Hsu, M.J.; Selvaraj, K.; Agoramoorthy, G.

    2006-01-01

    The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan

  6. Community-level plant-soil feedbacks explain landscape distribution of native and non-native plants.

    Science.gov (United States)

    Kulmatiski, Andrew

    2018-02-01

    Plant-soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short-term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non-native species, or a mixed plant community in different plots in a common-garden experiment. After 4 years, plants were removed and one native and one non-native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non-native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non-native, Centaurea diffusa , and non-native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata . Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common-garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non-native plant community on non-native soils. In contrast, when PSF effects were removed, the model predicted that non-native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank-order abundance of native and non-native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors

  7. Diversity of MAPs in some plant communities of Stara Planina

    Directory of Open Access Journals (Sweden)

    Obratov-Petković Dragica

    2006-01-01

    Full Text Available The high floristic diversity of Stara Planina was the starting base for the research of medicinal and aromatic plants (MAPs in individual forest and meadow communities. The sites Javor and Prelesje, forest community Fagetum moesiacae montanum B. Jov. 1953, pioneer community of birch Betuletum verrucosae s.l. and meadow community Agrostietum vulgaris (capillaris Pavlović, Z. 1955, were researched as follows: soil types, floristic composition and structure of the community, percentage of MAPs, as well as the selection of species which, according to the predetermined criteria can be recommended for further exploitation. The study shows that the soil of the forest communities is eutric brown, and meadow soils are dystric and eutric humus-siliceous. The percentage of MAPs in the floristic structure of the study sites in forest and meadow communities is 32.35%. The following species can be recommended for the collection and utilisation: Hypericum perforatum L., Asperula odorata L., Dryopteris filix-mas (L Schott. Urtica dioica L., Euphorbia amygdaloides L., Prunella grandiflora L. Tanacetum vulgare L., Achillea millefolium L., Rumex acetosa L., Campanula glomerata L., Stachys officinalis (L Trevis., Plantago lanceolata W. et K., Potentilla erecta (L Rauchel, Chamaespartium sagittale (L P. Gibbs. Cynanchum vincetoxicum (L Pers., Euphrasia stricta Host., Fagus moesiaca (Matt Liebl. and Fragaria vesca L.

  8. The role of plant mycorrhizal type and status in modulating the relationship between plant and arbuscular mycorrhizal fungal communities.

    Science.gov (United States)

    Neuenkamp, Lena; Moora, Mari; Öpik, Maarja; Davison, John; Gerz, Maret; Männistö, Minna; Jairus, Teele; Vasar, Martti; Zobel, Martin

    2018-01-25

    Interactions between communities of plants and arbuscular mycorrhizal (AM) fungi shape fundamental ecosystem properties. Experimental evidence suggests that compositional changes in plant and AM fungal communities should be correlated, but empirical data from natural ecosystems are scarce. We investigated the dynamics of covariation between plant and AM fungal communities during three stages of grassland succession, and the biotic and abiotic factors shaping these dynamics. Plant communities were characterised using vegetation surveys. AM fungal communities were characterised by 454-sequencing of the small subunit rRNA gene and identification against the AM fungal reference database MaarjAM. AM fungal abundance was estimated using neutral-lipid fatty acids (NLFAs). Multivariate correlation analysis (Procrustes) revealed a significant relationship between plant and AM fungal community composition. The strength of plant-AM fungal correlation weakened during succession following cessation of grassland management, reflecting changes in the proportion of plants exhibiting different AM status. Plant-AM fungal correlation was strong when the abundance of obligate AM plants was high, and declined as the proportion of facultative AM plants increased. We conclude that the extent to which plants rely on AM symbiosis can determine how tightly communities of plants and AM fungi are interlinked, regulating community assembly of both symbiotic partners. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  9. Terrestrial ecosystems and biodiversity

    CSIR Research Space (South Africa)

    Davis-Reddy, Claire

    2017-10-01

    Full Text Available Ecoregions Terrestrial Biomes Protected Areas Climate Risk and Vulnerability: A Handbook for Southern Africa | 75 7.2. Non-climatic drivers of ecosystem change 7.2.1. Land-use change, habitat loss and fragmentation Land-use change and landscape... concentrations of endemic plant and animal species, but these mainly occur in areas that are most threatened by human activity. Diverse terrestrial ecosystems in the region include tropical and sub-tropical forests, deserts, savannas, grasslands, mangroves...

  10. Mapping of aggregated floodplain plant communities using image fusion of CASI and LiDAR data

    NARCIS (Netherlands)

    Verrelst, J.; Geerling, G.W.; Sykora, K.V.; Clevers, J.G.P.W.

    2009-01-01

    Combined optical and laser altimeter data offer the potential to map and monitor plant communities based on their spectral and structural characteristics. A problem unresolved is, however, that narrowly defined plant communities, i.e. plant communities at a low hierarchical level of classification

  11. The effect of environmental change on vascular plant and cryptogam communities from the Falkland Islands and the Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    Convey Peter

    2007-12-01

    Full Text Available Abstract Background Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant communities in the Maritime Antarctic region (cryptogams only and the Falkland Islands (vascular plants only. We compared communities from the Falkland Islands (51°S, mean annual temperature 7.9°C, with those of Signy Island (60°S, -2.1°C and Anchorage Island (67°S, -2.6°C, and experimental temperature manipulations at each of the three islands using Open Top Chambers (OTCs. Results Despite the strong difference in plant growth form dominance between the Falkland Islands and the Maritime Antarctic, communities across the gradient did not differ in total diversity and species number. During the summer months, the experimental temperature increase at 5 cm height in the vegetation was similar between the locations (0.7°C across the study. In general, the response to this experimental warming was low. Total lichen cover showed a non-significant decreasing trend at Signy Island (p Conclusion These results suggest that small temperature increases may rapidly lead to decreased soil moisture, resulting in more stressful conditions for plants. The more open plant communities (grass and lichen appeared more negatively affected by such changes than dense communities (dwarf shrub and moss.

  12. Belowground Carbon Allocation and Plant-Microbial Interactions Drive Resistance and Resilience of Mountain Grassland Communities to Drought

    Science.gov (United States)

    Karlowsky, S.; Augusti, A.; Ingrisch, J.; Hasibeder, R.; Lavorel, S.; Bahn, M.; Gleixner, G.

    2016-12-01

    Belowground carbon allocation (BCA) and plant-microbial interactions are crucial for the functioning of terrestrial ecosystems. Recent research suggests that extreme events can have severe effects on these processes but it is unknown how land use intensity potentially modifies their responses. We studied the resistance and resilience of mountain grassland communities to prolonged drought and investigated the role of plant C allocation and soil microbial communities in mediating drought resistance and immediate recovery. In a common garden experiment we exposed monoliths from an abandoned grassland and a hay meadow to an early summer drought. Two independent 13C pulse labeling experiments were conducted, the first during peak drought and the second during the recovery phase. The 13C incorporation was analyzed in above- and belowground plant parts and in phospho- and neutral lipid fatty acids of soil microorganisms. In addition, a 15N label was added at the rewetting to determine plant N uptake. We found that C uptake, BCA and C transfer to soil microorganisms were less strongly reduced by drought in the abandoned grassland than in the meadow. Moreover, drought induced an increase of arbuscular mycorrhiza fungi (AMF) marker in the abandoned grassland. Nevertheless, C uptake and related parameters were quickly recovered and N uptake increased in the meadow during recovery. Unexpectedly, AMF and their C uptake were generally reduced during recovery, while bacteria increased and quickly recovered C uptake, particularly in the meadow. Our results showed a negative relation between high resistance and fast recovery. The more resistant abandoned grassland plant communities seemed to invest more C below ground and into interactions with AMF during drought, likely to access water through their hyphal network. Conversely, meadow communities invested more C from recent photosynthesis into bacterial communities during recovery, obviously to gain more nutrients for regrowth

  13. Development of an improved compact package plant for small community waste-water treatment

    CSIR Research Space (South Africa)

    Hulsman, A

    1993-01-01

    Full Text Available The challenges facing the design and operation of small community wastewater treatment plants are discussed. The package plant concept is considered and the consequent development of a compact intermittently aerated activated sludge package plant...

  14. The impact of plant chemical diversity on plant-herbivore interactions at the community level.

    Science.gov (United States)

    Salazar, Diego; Jaramillo, Alejandra; Marquis, Robert J

    2016-08-01

    Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants.

  15. Conceptual hierarchical modeling to describe wetland plant community organization

    Science.gov (United States)

    Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

    2010-01-01

    Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

  16. Abandoned floodplain plant communities along a regulated dryland river

    Science.gov (United States)

    Reynolds, L. V.; Shafroth, Patrick B.; House, P. K.

    2014-01-01

    Rivers and their floodplains worldwide have changed dramatically over the last century because of regulation by dams, flow diversions and channel stabilization. Floodplains no longer inundated by river flows following dam-induced flood reduction comprise large areas of bottomland habitat, but the effects of abandonment on plant communities are not well understood. Using a hydraulic flow model, geomorphic mapping and field surveys, we addressed the following questions along the Bill Williams River, Arizona: (i) What per cent of the bottomland do abandoned floodplains comprise? and (ii) Are abandoned floodplains quantitatively different from adjacent xeric and riparian surfaces in terms of vegetation composition and surface sediment? We found that nearly 70% of active channel and floodplain area was abandoned following dam installation. Abandoned floodplains along the Bill Williams River tend to be similar to each other yet distinct from neighbouring habitats: they have been altered physically from their historic state, leading to distinct combinations of surface sediments, hydrology and plant communities. Abandoned floodplains may transition to xeric communities over time but are likely to retain some riparian qualities as long as there is access to relatively shallow ground water. With expected increases in water demand and drying climatic conditions in many regions, these surfaces and associated vegetation will continue to be extensive in riparian landscapes worldwide

  17. Stable hydrogen isotopic composition of n-alkanes in atmospheric aerosols as a tracer for the source region of terrestrial plant waxes

    Science.gov (United States)

    Yamamoto, S.; Kawamura, K.

    2009-12-01

    Studies on molecular composition and compound-specific carbon isotopic ratio (δ13C) of leaf wax n-alkanes in atmospheric aerosols have revealed a long-range atmospheric transport of terrestrial higher plant materials over the south Atlantic and western Pacific oceans. However, molecular and δ13C compositions of terrestrial plant waxes in the eastern part of the Asian continent are relatively constant reflecting C3-dominated vegetation, which makes it difficult to specify the source regions of plant materials in the atmospheric aerosols over the East Asia and northwest Pacific regions. Recent observation displays a large (>100‰) spatial variation in hydrogen isotopic composition (δD) of rainwater in East Asia. Because δD values of terrestrial higher plants sensitively reflect those of precipitation waters, δD of leaf waxes are expected to provide information on their source region. In this study, we measured the δD of n-alkanes in atmospheric aerosols from Tokyo to better understand the origin of leaf wax n-alkanes in atmospheric aerosols. The δD values of fossil fuel n-alkanes (C21 to C24) in Tokyo aerosols range from -65 to -94‰, which are in a range of those reported in marine crude oils. In contrast, the δD of higher molecular weight (C29 and C31) n-alkanes (δDHMW) show much larger values by ~70‰ than those of fossil fuel n-alkanes. Their values were found to exhibit concomitant variations with carbon preference index (CPI), suggesting that the δDHMW reflect the δD of leaf wax n-alkanes with a variable contribution from fossil fuel n-alkanes. Nevertheless, good positive correlation (r = 0.89, p < 0.01) between the δDHMW and CPI values enable us to remove the contribution of fossil fuels using a mass balance approach by assuming that CPI of fossil fuel is 1 and CPI of plant waxes is 5-15. Calculated n-alkane δD values averaged from -170 to -185‰ for C29 and from -155 to -168‰ for C31. These values are consistent with those reported from

  18. Preliminary study of the 129I distribution in environment of La Hague reprocessing plant with the help of a terrestrial moss: Homalotecium sericeum. Study report

    International Nuclear Information System (INIS)

    1999-01-01

    The preliminary study of the 129 I distribution has allowed to underline the limits of use of a Homalotecium sericeum type terrestrial moss as biological indicator. However, this preliminary study allowed all the same to give a spatial distribution of this radioelement around La Hague reprocessing plant (source term) that underlines the existence of four geographic areas in function of collected activities. The levels are generally under 99 Bq/kg dry. It is recommended to improve the knowledge that we can have of transfers and quantity of iodine 129 from the marine environment to the terrestrial environment, but also, the one that we can have of factors able to modify the spatial distribution of this radionuclide. (N.C.)

  19. Differences in p,p'-DDE bioaccumulation from compost and soil by the plants Cucurbita pepo and Cucurbita maxima and the earthworms Eisenia fetida and Lumbricus terrestris

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Richard [Program in Environmental Science and Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, PA 18104 (United States)]. E-mail: rp232604@muhlenberg.edu; Kelsey, Jason W. [Program in Environmental Science and Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, PA 18104 (United States)]. E-mail: kelsey@muhlenberg.edu; White, Jason C. [Department of Soil and Water, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, CT 06504 (United States)]. E-mail: jason.white@po.state.ct.us

    2007-07-15

    Two plant species, Cucurbita pepo and Cucurbita maxima, and two earthworm species, Eisenia fetida and Lumbricus terrestris, were exposed to soil and compost with equivalent p,p'-DDE contamination. Pollutant bioconcentration was equal in plant roots in both media, but translocation was higher in C. pepo. Bioaccumulation by E. fetida was approximately 6- and 3-fold higher than that by L. terrestris in the soil and compost, respectively. For all species, p,p'-DDE uptake was significantly greater from soil than from compost; 7- to 8-fold higher for plant roots and 3- to 7-fold higher for worms. Abiotic desorption from soil was approximately twice that from the compost. When all the data are normalized for organic-carbon content of the media, the contaminant is more tightly bound by soil than compost. Although the risk associated with p,p'-DDE is higher in soil than compost, important mechanistic differences exist in contaminant binding to organic carbon in the two media. - Availability of p,p'-DDE to earthworms and plants was dramatically different in soil and compost.

  20. Differences in p,p'-DDE bioaccumulation from compost and soil by the plants Cucurbita pepo and Cucurbita maxima and the earthworms Eisenia fetida and Lumbricus terrestris

    International Nuclear Information System (INIS)

    Peters, Richard; Kelsey, Jason W.; White, Jason C.

    2007-01-01

    Two plant species, Cucurbita pepo and Cucurbita maxima, and two earthworm species, Eisenia fetida and Lumbricus terrestris, were exposed to soil and compost with equivalent p,p'-DDE contamination. Pollutant bioconcentration was equal in plant roots in both media, but translocation was higher in C. pepo. Bioaccumulation by E. fetida was approximately 6- and 3-fold higher than that by L. terrestris in the soil and compost, respectively. For all species, p,p'-DDE uptake was significantly greater from soil than from compost; 7- to 8-fold higher for plant roots and 3- to 7-fold higher for worms. Abiotic desorption from soil was approximately twice that from the compost. When all the data are normalized for organic-carbon content of the media, the contaminant is more tightly bound by soil than compost. Although the risk associated with p,p'-DDE is higher in soil than compost, important mechanistic differences exist in contaminant binding to organic carbon in the two media. - Availability of p,p'-DDE to earthworms and plants was dramatically different in soil and compost

  1. Repression of fungal plant pathogens and fungal-related contaminants: Selected ecosystem services by soil fauna communities in agroecosystems

    Science.gov (United States)

    Meyer-Wolfarth, Friederike; Schrader, Stefan; Oldenburg, Elisabeth; Brunotte, Joachim; Weinert, Joachim

    2017-04-01

    In agroecosystems soil-borne fungal plant diseases are major yield-limiting factors which are difficult to control. Fungal plant pathogens, like Fusarium species, survive as a saprophyte in infected tissue like crop residues and endanger the health of the following crop by increasing the infection risk for specific plant diseases. In infected plant organs, these pathogens are able to produce mycotoxins. Mycotoxins like deoxynivalenol (DON) persist during storage, are heat resistant and of major concern for human and animal health after consumption of contaminated food and feed, respectively. Among fungivorous soil organisms, there are representatives of the soil fauna which are obviously antagonistic to a Fusarium infection and the contamination with mycotoxins. Specific members of the soil macro-, meso-, and microfauna provide a wide range of ecosystem services including the stimulation of decomposition processes which may result in the regulation of plant pathogens and the degradation of environmental contaminants. Investigations under laboratory conditions and in field were conducted to assess the functional linkage between soil faunal communities and plant pathogenic fungi (Fusarium culmorum). The aim was to examine if Fusarium biomass and the content of its mycotoxin DON decrease substantially in the presence of soil fauna (earthworms: Lumbricus terrestris, collembolans: Folsomia candida and nematodes: Aphelenchoides saprophilus) in a commercial cropping system managed with conservation tillage located in Northern Germany. The results of our investigations pointed out that the degradation performance of the introduced soil fauna must be considered as an important contribution to the biodegradation of fungal plant diseases and fungal-related contaminants. Different size classes within functional groups and the traits of keystone species appear to be significant for soil function and the provision of ecosystem services as in particular L. terrestris revealed to

  2. Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

    Science.gov (United States)

    Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

    2017-12-01

    Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

  3. Population and community ecology of the rare plant amsinckia grandiflora

    Energy Technology Data Exchange (ETDEWEB)

    Carlsen, T.M.

    1996-11-01

    Research was conducted between the fall of 1992 and the spring on the population and community ecology of the rare annual plant, Amsinckia glandiflora (Gray) Kleeb. ex Greene (Boraginaceae). The research goal was to investigate the causes of the species rarity, data useful to restorative efforts. The work focused on the examination of competitive suppression by exotic annual grasses; comparisons with common, weedy congener; and the role of litter cover and seed germination and seedling establishment. Annual exotic grasses reduced A. grandiflora reproductive output to a greater extent than did the native perennial bunch grass.

  4. Engineering a plant community to deliver multiple ecosystem services.

    Science.gov (United States)

    Storkey, Jonathan; Döring, Thomas; Baddeley, John; Collins, Rosemary; Roderick, Stephen; Jones, Hannah; Watson, Christine

    2015-06-01

    The sustainable delivery of multiple ecosystem services requires the management of functionally diverse biological communities. In an agricultural context, an emphasis on food production has often led to a loss of biodiversity to the detriment of other ecosystem services such as the maintenance of soil health and pest regulation. In scenarios where multiple species can be grown together, it may be possible to better balance environmental and agronomic services through the targeted selection of companion species. We used the case study of legume-based cover crops to engineer a plant community that delivered the optimal balance of six ecosystem services: early productivity, regrowth following mowing, weed suppression, support of invertebrates, soil fertility building (measured as yield of following crop), and conservation of nutrients in the soil. An experimental species pool of 12 cultivated legume species was screened for a range of functional traits and ecosystem services at five sites across a geographical gradient in the United Kingdom. All possible species combinations were then analyzed, using a process-based model of plant competition, to identify the community that delivered the best balance of services at each site. In our system, low to intermediate levels of species richness (one to four species) that exploited functional contrasts in growth habit and phenology were identified as being optimal. The optimal solution was determined largely by the number of species and functional diversity represented by the starting species pool, emphasizing the importance of the initial selection of species for the screening experiments. The approach of using relationships between functional traits and ecosystem services to design multifunctional biological communities has the potential to inform the design of agricultural systems that better balance agronomic and environmental services and meet the current objective of European agricultural policy to maintain viable food

  5. Phytopharmacology of Tribulus terrestris.

    Science.gov (United States)

    Shahid, M; Riaz, M; Talpur, M M A; Pirzada, T

    2016-01-01

    Tribulus terrestris is an annual herb which belongs to the Zygophyllaceae family. This plant has been used in traditional medicine for the treatment of various diseases for hundreds of decades. The main active phytoconstituents of this plant include flavonoids, alkaloids, saponins, lignin, amides, and glycosides. The plant parts have different pharmacological activities including aphrodisiac, antiinflammatory, antimicrobial and antioxidant potential. T. terrestris is most often used for infertility and loss of libido. It has potential application as immunomodulatory, hepatoprotective, hypolipidemic, anthelmintic and anticarcinogenic activities. The aim of the present article is to create a database for further investigation of the phytopharmacological properties of this plant to promote research. This study will definitely help to confirm its traditional use along with its value-added utility, eventually leading to higher revenues from the plant.

  6. Carbon cost of plant nitrogen acquisition: global carbon cycle impact from an improved plant nitrogen cycle in the Community Land Model.

    Science.gov (United States)

    Shi, Mingjie; Fisher, Joshua B; Brzostek, Edward R; Phillips, Richard P

    2016-03-01

    Plants typically expend a significant portion of their available carbon (C) on nutrient acquisition - C that could otherwise support growth. However, given that most global terrestrial biosphere models (TBMs) do not include the C cost of nutrient acquisition, these models fail to represent current and future constraints to the land C sink. Here, we integrated a plant productivity-optimized nutrient acquisition model - the Fixation and Uptake of Nitrogen Model - into one of the most widely used TBMs, the Community Land Model. Global plant nitrogen (N) uptake is dynamically simulated in the coupled model based on the C costs of N acquisition from mycorrhizal roots, nonmycorrhizal roots, N-fixing microbes, and retranslocation (from senescing leaves). We find that at the global scale, plants spend 2.4 Pg C yr(-1) to acquire 1.0 Pg N yr(-1) , and that the C cost of N acquisition leads to a downregulation of global net primary production (NPP) by 13%. Mycorrhizal uptake represented the dominant pathway by which N is acquired, accounting for ~66% of the N uptake by plants. Notably, roots associating with arbuscular mycorrhizal (AM) fungi - generally considered for their role in phosphorus (P) acquisition - are estimated to be the primary source of global plant N uptake owing to the dominance of AM-associated plants in mid- and low-latitude biomes. Overall, our coupled model improves the representations of NPP downregulation globally and generates spatially explicit patterns of belowground C allocation, soil N uptake, and N retranslocation at the global scale. Such model improvements are critical for predicting how plant responses to altered N availability (owing to N deposition, rising atmospheric CO2 , and warming temperatures) may impact the land C sink. © 2015 John Wiley & Sons Ltd.

  7. The distribution of tritium in the terrestrial and aquatic environments of the Creys-Malville nuclear power plant (2002-2005)

    International Nuclear Information System (INIS)

    Jean-Baptiste, P.; Baumier, D.; Fourre, E.; Dapoigny, A.; Clavel, B.

    2007-01-01

    The Creys-Malville nuclear plant, located on the left bank of the Rhone, was shut down in 1998. The facilities are currently in their initial stage of dismantling. In order to establish a baseline for tritium in the vicinity of the site prior to the main dismantling phase, we carried out a monitoring program between 2002 and 2005 in the main terrestrial and aquatic compartments of the local environment. Tritium levels in the groundwaters and in the Rhone waters correspond to the regional tritium concentration in precipitation. The data obtained for the terrestrial environment are also in good agreement with the regional background and do not show any specific signature linked to the nuclear plant. The various aquatic compartments of the Rhone (fish, plant, sediment) are significantly enriched in tritium both upstream and downstream of the power plant: although Tissue-Free Water Tritium concentrations are in equilibrium with the river water, the non-exchangeable fraction of organic bound tritium in plants and fishes shows values which outpace the river water background by one to two orders of magnitude, and up to four to five orders of magnitude in the sediments. This tritium anomaly is not related to the nuclear plant, as it is already present at the Swiss border 100 km upstream of the site. Although fine particles of tritiated polystyrene entering the composition of the luminous paints used by the clock industry have been suspected on several occasions, the exact nature and the origin of this tritium source remain unknown and require further investigations

  8. Differences in p,p'-DDE bioaccumulation from compost and soil by the plants Cucurbita pepo and Cucurbita maxima and the earthworms Eisenia fetida and Lumbricus terrestris.

    Science.gov (United States)

    Peters, Richard; Kelsey, Jason W; White, Jason C

    2007-07-01

    Two plant species, Cucurbita pepo and Cucurbita maxima, and two earthworm species, Eisenia fetida and Lumbricus terrestris, were exposed to soil and compost with equivalent p,p'-DDE contamination. Pollutant bioconcentration was equal in plant roots in both media, but translocation was higher in C. pepo. Bioaccumulation by E. fetida was approximately 6- and 3-fold higher than that by L. terrestris in the soil and compost, respectively. For all species, p,p'-DDE uptake was significantly greater from soil than from compost; 7- to 8-fold higher for plant roots and 3- to 7-fold higher for worms. Abiotic desorption from soil was approximately twice that from the compost. When all the data are normalized for organic-carbon content of the media, the contaminant is more tightly bound by soil than compost. Although the risk associated with p,p'-DDE is higher in soil than compost, important mechanistic differences exist in contaminant binding to organic carbon in the two media.

  9. Moving forward on facilitation research: response to changing environments and effects on the diversity, functioning and evolution of plant communities

    Science.gov (United States)

    Soliveres, Santiago; Smit, Christian; Maestre, Fernando T.

    2015-01-01

    Once seen as anomalous, facilitative interactions among plants and their importance for community structure and functioning are now widely recognized. The growing body of modelling, descriptive and experimental studies on facilitation covers a wide variety of terrestrial and aquatic systems throughout the globe. However, the lack of a general body of theory linking facilitation among different types of organisms and biomes and their responses to environmental changes prevents further advances in our knowledge regarding the evolutionary and ecological implications of facilitation in plant communities. Moreover, insights gathered from alternative lines of inquiry may substantially improve our understanding of facilitation, but these have been largely neglected thus far. Despite over 15 years of research and debate on this topic, there is no consensus on the degree to which plant–plant interactions change predictably along environmental gradients (i.e. the stress-gradient hypothesis), and this hinders our ability to predict how plant–plant interactions may affect the response of plant communities to ongoing global environmental change. The existing controversies regarding the response of plant–plant interactions across environmental gradients can be reconciled when clearly considering and determining the species-specificity of the response, the functional or individual stress type, and the scale of interest (pairwise interactions or community-level response). Here, we introduce a theoretical framework to do this, supported by multiple lines of empirical evidence. We also discuss current gaps in our knowledge regarding how plant–plant interactions change along environmental gradients. These include the existence of thresholds in the amount of species-specific stress that a benefactor can alleviate, the linearity or non-linearity of the response of pairwise interactions across distance from the ecological optimum of the beneficiary, and the need to explore

  10. Community leaders' perspectives on socio-economic impacts of power-plant development

    International Nuclear Information System (INIS)

    Hastings, M.; Cawley, M.E.

    1981-01-01

    The primary focus of this research effort was to identify and measure the socioeconomic impacts of power plant development on non-metropolitan host communities. A mail survey, distributed to community leaders in 100 power plant communities east of the Mississippi River, was utilized to gather information from 713 respondents. Community leaders were questioned as to the plant's impact on (a) community groups, (b) aspects of community life, (c) overall community acceptance and (d) attitudes toward power plant development. Overall, the trends and patterns of plant impact on the host communities were found to be largely positive. Specifically, local employment opportunities were generally enhanced with the advent of the power plant. Directly related to power plant development was the overall improvement of the local economic situation. Off-shoots from such in the economic area included related general improvements in the community quality of life. While the vast majority of community leaders responded with positive comments on power plant presence, adverse impacts were also mentioned. Negative comments focused on environmental problems, deterioration of roads and traffic conditions, and the possibility of nuclear accidents. Despite these negative impacts, almost two-thirds of the community leaders would definitely support the reconstruction of the same energy facility. Power plant development, therefore, is generally perceived as both a positive and beneficial asset for the host area. (author)

  11. Terrestrial ecology. Comprehensive study of the grassland biome

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Terrestrial ecology and grassland biome studies are designed to characterize the biota of the Hanford Reservation, elucidate seasonal dynamics of plant productivity, decomposition and mineral behavior patterns of important plant communities, and, to study the response of these communities to important natural environmental stresses, such as weather, wildfire and man-induced alterations of communities (influenced by grazing cattle and severe mechanical disturbance of the soil, such as affected by plowing or burial of waste materials or construction activities). A detailed account of the important findings of a 5-yr study is currently being prepared by the terrestrial ecology section staff for publication as a contribution to the International Biological Program Grassland Biome project

  12. Interspecific nutrient transfer in a tallgrass prairie plant community

    International Nuclear Information System (INIS)

    Walter, L.E.F.; Hartnett, D.C.; Hetrick, B.A.D.; Schwab, A.P.

    1996-01-01

    Interplant nutrient transfer may be an important ecological process in grasslands, and may significantly influence plant neighborhood interactions. We investigated the potential for phosphorus transfer between the dominant grass Andropogon gerardii and several neighboring plant species in tallgrass prairie via a field 32PO4 labelling experiment. The mean amount of 32P received from donor shoots differed significantly among neighboring species and decreased with increasing distance from the donor. In general, forbs and cool-season C3 grasses received more labelled 32P than warm-season C4 grasses. Phosphorus transfer occurred over distances up to 0.5 m. The effects of species and distance on movement of phosphorus changed with increasing time after labelling. The relative mass of receiver and donor shoots did not affect amounts of 32P transfer. A benomyl fungicide treatment, applied to suppress mycorrhizal activity, likely did not affect existing vegetative hyphae and did not affect the amount of 32P transferred. These studies demonstrate that: (1) phosphorus is transferred among neighboring species in tallgrass prairie plant communities, (2) phosphorus may be transferred over significantly greater distances than reported in other grasslands, and (3) there is differential transfer among co-occurring species. Hypothesized mechanisms accounting for these patterns in tallgrass prairie include mycorrhizal hyphal interconnections and/or extensive and differential root and rhizosphere overlap among neighboring species

  13. Species and rotation frequency influence soil nitrogen in simplified tropical plant communities.

    Science.gov (United States)

    Ewel, John J

    2006-04-01

    Among the many factors that potentially influence the rate at which nitrogen (N) becomes available to plants in terrestrial ecosystems are the identity and diversity of species composition, frequency of disturbance or stand turnover, and time. Replicated suites of investigator-designed communities afforded an opportunity to examine the effects of those factors on net N mineralization over a 12-year period. The communities consisted of large-stature perennial plants, comprising three tree species (Hyeronima alchorneoides, Cedrela odorata, and Cordia alliodora), a palm (Euterpe oleracea), and a large, perennial herb (Heliconia imbricata). Trees were grown in monoculture and in combination with the other two life-forms; tree monocultures were subjected to rotations of one or four years, or like the three-life-form systems, left uncut. The work was conducted on fertile soil in the humid lowlands of Costa Rica, a site with few abiotic constraints to plant growth. Rates of net N mineralization and nitrification were high, typically in the range of 0.2-0.8 microg x g(1) x d(-1), with net nitrification slightly higher than net mineralization, indicating preferential uptake of ammonium (NH4+) by plants and microbes. Net rates of N mineralization were about 30% lower in stands of one of the three tree species, Hyeronima, than in stands of the other two. Contrary to expectations, short-rotation management (one or four years) resulted in higher net rates of N mineralization than in uncut stands, whether the latter were composed of a single tree species or a combination of life-forms. Neither additional species richness nor replenishment of leached N augmented mineralization rates. The net rate at which N was supplied tended to be lowest in stands where demand for N was highest. Careful choice of species, coupled with low frequency of disturbance, can lead to maintenance of N within biomass and steady rates of within-system circulation, whereas pulses, whether caused by cutting

  14. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Bocock, K.L.

    1981-01-01

    This report summarizes information on the distribution and movement of radionuclides in semi-natural terrestrial ecosystems in north-west England with particular emphasis on inputs to, and outputs from ecosystems; on plant and soil aspects; and on radionuclides in fallout and in discharges by the nuclear industry. (author)

  15. The treatment of jaundice with medicinal plants in indigenous communities of the Sub-Himalayan region of Uttarakhand, India.

    Science.gov (United States)

    Sharma, Jyotsana; Gairola, Sumeet; Gaur, R D; Painuli, R M

    2012-08-30

    , external and magico-religious remedies for jaundice, respectively by various communities in different parts of India. Most widely used hepatoprotective plant species for treatment of jaundice in India is Boerhavia diffusa L. followed by Tinospora cordifolia (Willd.) Miers, Saccharum officinarum L., Phyllanthus amarus Schumach. & Thonn., Ricinus communis L., Andrographis paniculata (Burm. f.) Nees., Oroxylum indicum (L.) Kurz, Lawsonia inermis L. and Eclipta prostrata (L.) L. The plants recorded in the present survey have also been discussed in relation to pharmacological studies and hepatoprotective phytoconstituents present in them. Most of the recorded plants have shown hepatoprotective effects on experimental animals in earlier studies but more studies are needed to assess hepatoprotective properties of some recorded medicinal plants viz., Averrhoa carambola L., Ehretia laevis Roxb., Holarrhena pubescens Wall., Mangifera indica L., Ocimum americanum L., Oroxylum indicum (L.) Kurz, Physalis divaricata D. Don, Solanum incanum L., Sphaeranthus senegalensis DC. and Tribulus terrestris L.. The plants enumerated in this study with high number of citations and wider distributions have given some useful leads for further biomedical research. Nevertheless more phytochemical, pharmaceutical and clinical studies are needed to evaluate hepatoprotective properties, efficacy and safety of all the claimed medicinal plants. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  16. Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

    Directory of Open Access Journals (Sweden)

    Nico Eisenhauer

    Full Text Available Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.We studied the functional composition of nematode communities three and five years after establishment of a grassland plant diversity experiment (Jena Experiment. In response to plant community simplification common nematode species disappeared and pronounced functional shifts in community structure occurred. The relevance of the fungal energy channel was higher in spring 2007 than in autumn 2005, particularly in species-rich plant assemblages. This resulted in a significant positive relationship between plant species richness and the ratio of fungal-to-bacterial feeders. Moreover, the density of predators increased significantly with plant diversity after five years, pointing to increased soil food web complexity in species-rich plant assemblages. Remarkably, in complex plant communities the nematode community shifted in favour of microbivores and predators, thereby reducing the relative abundance of plant feeders after five years.The results suggest that species-poor plant assemblages may suffer from nematode communities detrimental to plants, whereas species-rich plant assemblages support a higher proportion of microbivorous nematodes stimulating nutrient cycling and hence plant performance; i.e. effects of nematodes on plants may switch from negative to positive. Overall, food web complexity is likely to decrease in response to plant community simplification and results of this study suggest that this results mainly from the loss of common species which likely alter plant-nematode interactions.

  17. Monitoring of radionuclides in the terrestrial and aquatic environment of the nuclear power plant at Barsebaeck (Sweden) for the period 1984-1991

    International Nuclear Information System (INIS)

    Neumann, G.

    1994-01-01

    This report summarizes the main results from the environment monitoring sampling for the years 1984-1991 around the nuclear power plant at Barsebaeck, southern Sweden. The sampling are required according to the environment monitoring programme which has been decided upon by the Swedish Radiation Protection Inst. Terrestrial samples include cultivated plants, natural vegetation, milk, some other foods of animal origin and sludge. From the aquatic environment, samples of sea water, bottom sediments, benthic fauna, algae and fish are collected. This report accounts for all samples that have been measured during the period 1984-1991. The diagrams also include data from the years 1981-1983. The annual discharge to air and to water resulted during the years 1984-1991 in a dose commitment to a critical group which generally amounted to less than 2 micro-sievert (which equals 2 per cent of the maximum permitted, viz. one Norm release). The annual radiation dose outside the power plant has always been found less than 0.2% of that from the background radiation. Outside the plant, only very small quantities of radionuclides were detected which could be related to its operation. Radionuclides from the power plant have not with certainty been detected in cultivated plants, milk, and meat produced in the vicinity of the power plant. On the other hand small quantities of Co-60 and Zn-65 from the plant were detected in, for instance, some samples of eel and cod from stations close to the plant. In 1985 and 1989, special sediment sampling were carried out at 12 stations off Barsebaeck. One aim was to investigate whether any accumulation of radionuclides from Barsebaeck in bottom sediments had occurred during the period. There was no clear evidence of any such accumulation. 15 refs, 22 figs, 16 tabs

  18. Climate impacts on bird and plant communities from altered animal-plant interactions

    Science.gov (United States)

    Martin, Thomas E.; Maron, John L.

    2012-01-01

    The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

  19. Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

    Science.gov (United States)

    Krüger, Claudia; Kohout, Petr; Janoušková, Martina; Püschel, David; Frouz, Jan; Rydlová, Jana

    2017-01-01

    Arbuscular mycorrhizal fungal (AMF) community assembly during primary succession has so far received little attention. It remains therefore unclear, which of the factors, driving AMF community composition, are important during ecosystem development. We addressed this question on a large spoil heap, which provides a mosaic of sites in different successional stages under different managements. We selected 24 sites of c. 12, 20, 30, or 50 years in age, including sites with spontaneously developing vegetation and sites reclaimed by alder plantations. On each site, we sampled twice a year roots of the perennial rhizomatous grass Calamagrostis epigejos (Poaceae) to determine AMF root colonization and diversity (using 454-sequencing), determined the soil chemical properties and composition of plant communities. AMF taxa richness was unaffected by site age, but AMF composition variation increased along the chronosequences. AMF communities were unaffected by soil chemistry, but related to the composition of neighboring plant communities of the sampled C. epigejos plants. In contrast, the plant communities of the sites were more distinctively structured than the AMF communities along the four successional stages. We conclude that AMF and plant community successions respond to different factors. AMF communities seem to be influenced by biotic rather than by abiotic factors and to diverge with successional age. PMID:28473828

  20. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates.

    Science.gov (United States)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP......-Terrestrial Plan/the Plan) as the framework for coordinated, long-term Arctic terrestrial biodiversity monitoring. The goal of the CBMP-Terrestrial Plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect, understand and report on long...

  2. Comparing herbaceous plant communities in active and passive riparian restoration.

    Directory of Open Access Journals (Sweden)

    Elise S Gornish

    Full Text Available Understanding the efficacy of passive (reduction or cessation of environmental stress and active (typically involving planting or seeding restoration strategies is important for the design of successful revegetation of degraded riparian habitat, but studies explicitly comparing restoration outcomes are uncommon. We sampled the understory herbaceous plant community of 103 riparian sites varying in age since restoration (0 to 39 years and revegetation technique (active, passive, or none to compare the utility of different approaches on restoration success across sites. We found that landform type, percent shade, and summer flow helped explain differences in the understory functional community across all sites. In passively restored sites, grass and forb cover and richness were inversely related to site age, but in actively restored sites forb cover and richness were inversely related to site age. Native cover and richness were lower with passive restoration compared to active restoration. Invasive species cover and richness were not significantly different across sites. Although some of our results suggest that active restoration would best enhance native species in degraded riparian areas, this work also highlights some of the context-dependency that has been found to mediate restoration outcomes. For example, since the effects of passive restoration can be quite rapid, this approach might be more useful than active restoration in situations where rapid dominance of pioneer species is required to arrest major soil loss through erosion. As a result, we caution against labeling one restoration technique as better than another. Managers should identify ideal restoration outcomes in the context of historic and current site characteristics (as well as a range of acceptable alternative states and choose restoration approaches that best facilitate the achievement of revegetation goals.

  3. Humans as long-distance dispersers of rural plant communities.

    Directory of Open Access Journals (Sweden)

    Alistair G Auffret

    Full Text Available Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for species threatened by habitat destruction, but research into human-mediated dispersal is often focused upon few and/or invasive species. Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a known species pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in an alternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24,354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71 species (36% are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendages were more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted in more dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances were measured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities in which they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might have been regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscape may have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat and changes in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role of humans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance and regional dispersal, and international invasion.

  4. Using the WOFOST plant growth model to built the data base of the terrestrial tritium and food chain modules in RODOS

    International Nuclear Information System (INIS)

    Melintescu, A.; Galeriu, D.; Marica, A.

    2003-01-01

    The European Commission Project RODOS implements a coherent methodology for a Real-time On-line Decision Support System for Nuclear Emergency across Europe. Within this system there is a special module to model the transfer of tritiated water from releases to terrestrial foods. In order to model the transfer of tritiated water from air to various plants, the conversion to organically bound tritium, and the migration to edible parts of the plant, both the mean dynamics of leaf area index and a physiological description of canopy photosynthesis are required. The WOFOST crop growth model has been selected as a basis for deriving tritium transfer dynamics to plants. Its ability to reproduce site-specific biomass growth of various plants (not only from Europe) is demonstrated in this paper, as well as its compatibility to other photosynthesis models. We have tested that this model can simulate limited fertilization situations via the adaptation of two important parameters. After adaptation of model parameters to site-specific plant growth data, multi-annual mean dynamics can be obtained using meteorological data for subsequent years. (authors)

  5. Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

    International Nuclear Information System (INIS)

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-01-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions

  6. Phylogenetic composition of host plant communities drives plant-herbivore food web structure.

    Science.gov (United States)

    Volf, Martin; Pyszko, Petr; Abe, Tomokazu; Libra, Martin; Kotásková, Nela; Šigut, Martin; Kumar, Rajesh; Kaman, Ondřej; Butterill, Philip T; Šipoš, Jan; Abe, Haruka; Fukushima, Hiroaki; Drozd, Pavel; Kamata, Naoto; Murakami, Masashi; Novotny, Vojtech

    2017-05-01

    Insects tend to feed on related hosts. The phylogenetic composition of host plant communities thus plays a prominent role in determining insect specialization, food web structure, and diversity. Previous studies showed a high preference of insect herbivores for congeneric and confamilial hosts suggesting that some levels of host plant relationships may play more prominent role that others. We aim to quantify the effects of host phylogeny on the structure of quantitative plant-herbivore food webs. Further, we identify specific patterns in three insect guilds with different life histories and discuss the role of host plant phylogeny in maintaining their diversity. We studied herbivore assemblages in three temperate forests in Japan and the Czech Republic. Sampling from a canopy crane, a cherry picker and felled trees allowed a complete census of plant-herbivore interactions within three 0·1 ha plots for leaf chewing larvae, miners, and gallers. We analyzed the effects of host phylogeny by comparing the observed food webs with randomized models of host selection. Larval leaf chewers exhibited high generality at all three sites, whereas gallers and miners were almost exclusively monophagous. Leaf chewer generality dropped rapidly when older host lineages (5-80 myr) were collated into a single lineage but only decreased slightly when the most closely related congeneric hosts were collated. This shows that leaf chewer generality has been maintained by feeding on confamilial hosts while only a few herbivores were shared between more distant plant lineages and, surprisingly, between some congeneric hosts. In contrast, miner and galler generality was maintained mainly by the terminal nodes of the host phylogeny and dropped immediately after collating congeneric hosts into single lineages. We show that not all levels of host plant phylogeny are equal in their effect on structuring plant-herbivore food webs. In the case of generalist guilds, it is the phylogeny of deeper

  7. Plant pathogens structure arthropod communities across multiple spatial and temporal scales

    NARCIS (Netherlands)

    Tack, A.J.M.; Dicke, M.

    2013-01-01

    Plant pathogens and herbivores frequently co-occur on the same host plants. Despite this, little is known about the impact of their interactions on the structure of plant-based ecological communities. Here, we synthesize evidence that indicates that plant pathogens may profoundly impact arthropod

  8. Methyl mercury in terrestrial compartments

    International Nuclear Information System (INIS)

    Stoeppler, M.; Burow, M.; Padberg, S.; May, K.

    1993-09-01

    On the basis of the analytical methodology available at present the state of the art for the determination of total mercury and of various organometallic compounds of mercury in air, precipitation, limnic systems, soils, plants and biota is reviewed. This is followed by the presentation and discussion of examples for the data obtained hitherto for trace and ultratrace levels of total mercury and mainly methyl mercury in terrestrial and limnic environments as well as in biota. The data discussed stem predominantly from the past decade in which, due to significant methodological progress, many new aspects were elucidated. They include the most important results in this area achieved by the Research Centre (KFA) Juelich within the project 'Origin and Fate of Methyl Mercury' (contracts EV4V-0138-D and STEP-CT90-0057) supported by the Commission of the European Communities, Brussels. (orig.) [de

  9. Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.

    Science.gov (United States)

    Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas

    2013-05-13

    Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant

  10. Pesticides from wastewater treatment plant effluents affect invertebrate communities.

    Science.gov (United States)

    Münze, Ronald; Hannemann, Christin; Orlinskiy, Polina; Gunold, Roman; Paschke, Albrecht; Foit, Kaarina; Becker, Jeremias; Kaske, Oliver; Paulsson, Elin; Peterson, Märit; Jernstedt, Henrik; Kreuger, Jenny; Schüürmann, Gerrit; Liess, Matthias

    2017-12-01

    We quantified pesticide contamination and its ecological impact up- and downstream of seven wastewater treatment plants (WWTPs) in rural and suburban areas of central Germany. During two sampling campaigns, time-weighted average pesticide concentrations (c TWA ) were obtained using Chemcatcher® passive samplers; pesticide peak concentrations were quantified with event-driven samplers. At downstream sites, receiving waters were additionally grab sampled for five selected pharmaceuticals. Ecological effects on macroinvertebrate structure and ecosystem function were assessed using the biological indicator system SPEAR pesticides (SPEcies At Risk) and leaf litter breakdown rates, respectively. WWTP effluents substantially increased insecticide and fungicide concentrations in receiving waters; in many cases, treated wastewater was the exclusive source for the neonicotinoid insecticides acetamiprid and imidacloprid in the investigated streams. During the ten weeks of the investigation, five out of the seven WWTPs increased in-stream pesticide toxicity by a factor of three. As a consequence, at downstream sites, SPEAR values and leaf litter degradation rates were reduced by 40% and 53%, respectively. The reduced leaf litter breakdown was related to changes in the macroinvertebrate communities described by SPEAR pesticides and not to altered microbial activity. Neonicotinoids showed the highest ecological relevance for the composition of invertebrate communities, occasionally exceeding the Regulatory Acceptable Concentrations (RACs). In general, considerable ecological effects of insecticides were observed above and below regulatory thresholds. Fungicides, herbicides and pharmaceuticals contributed only marginally to acute toxicity. We conclude that pesticide retention of WWTPs needs to be improved. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Effects of Plant Functional Group Loss on Soil Microbial Community and Litter Decomposition in a Steppe Vegetation.

    Science.gov (United States)

    Xiao, Chunwang; Zhou, Yong; Su, Jiaqi; Yang, Fan

    2017-01-01

    Globally, many terrestrial ecosystems are experiencing a rapid loss of biodiversity. Continued improvements in our understanding of interrelationships between plant diversity and soil microbes are critical to address the concern over the consequences of the decline in biodiversity on ecosystem functioning and services. By removing forbs, or grasses, or, to an extreme scenario, both forbs and grasses in a steppe vegetation in Inner Mongolia, we studied how plant functional group (PFG) loss affects soil microbial community composition using phospholipid fatty acid analysis (PLFA) and litter decomposition using a litter-bag method. PFG loss significantly decreased above- and below-ground plant biomass, soil microbial biomass carbon (SMBC) and nitrogen (SMBN), but had no effect on the ratio of SMBC to SMBN. Although the ratio of fungal to bacterial PLFAs remained unaffected, PFG loss significantly reduced the amount of bacterial, fungal, and total PLFAs. PFG loss decreased litter monthly mass loss and decay constant, and such decrease was significant when both forbs and grasses were removed. Our results provide robust evidence that PFG loss in grassland ecosystem can lead to a rapid response of soil microbial activity which may affect litter decomposition and soil nutrient cycling, suggesting that the assessment of plant-microbe interactions in soils is an integral component of ecosystem response to biodiversity loss.

  12. Plant community structure in an oligohaline tidal marsh

    Science.gov (United States)

    Brewer, J.S.; Grace, J.B.

    1990-01-01

    An oligohaline tidal marsh on the northern shore of Lake Pontchartrain, LA was characterized with respect to the distributions and abundances of plant species over spatial and temporal gradients using Detrended Correspondence Analysis (DCA). In addition, the species distributions were correlated to several physical environmental factors using Detrended Canonical Correspondence Analysis (DCCA). The distributions of species were best correlated with distance from Lake Pontchartrain, and to a lesser extent with elevation and substrate organic matter. They were least correlated with mean soil salinity (referred to here as background salinity). Of the three mid-seasonal dominant species, the perennial grass, Spartina patens, is the most salt tolerant and was found closest to the lake. Further inland the dominant perennial was Sagittaria lancifolia, which has a salt tolerance less than that of Spartina patens. The perennial sedge, Cladium jamaicense, which is the least salt tolerant of the three, was dominant furthest inland. Background salinity levels were generally low (interactions likely also play a role in structuring the plant community. The distributions of several annuals depended on the size and life history of the mid-seasonal dominant perennials. Most of the annuals frequently co-occurred with Sagittaria lancifolia, which was the shortest in stature and had the least persistent canopy of the three mid-seasonal dominant perennials.

  13. Mineralogical composition changes of postagrogenic soils under different plant communities.

    Science.gov (United States)

    Churilin, Nikita; Chizhikova, Natalia; Varlamov, Evgheni; Churilina, Alexandra

    2017-04-01

    Plant communities play the leading role in transformation of soil. The need of studying former arable lands increases due to large number of abandoned lands in Russia. It is necessary to study mineralogical composition of soils involved into natural processes to understand the trends of their development after agricultural activities in the past. The aim of the study is to identify changes in mineralogical composition of soils under the influence of different plant communities. Soils were sampled in the south of Arkhangelsk region, Ustyansky district, near Akichkin Pochinok village. Soils are formed on clay moraine of Moscow glaciation. Soil profiles were dug on interfluve. We selected 4 plant communities on different stages of succession: upland meadow with domination of sod grasses (Phleum pratense, Agrostis tenuis), 16-year-old birch forest where dominants are herbaceous plants such as Poa sp., Chamerion angustiflium, Agrostis tenuis, 16-year-old spruce forest with no herbaceous vegetation and 70-year-old bilberry spruce forest with domination of Vaccinium myrtillus and Vaccinium vitis-idaea. To separate soil fractions mineral content. We noticed a clear differentiation of studied soils both in the content of fraction and composition of minerals. Mineralogical composition and major mineral phases correlation of profiles under 70 years and 16 years of spruce forests are different. Mineralogical content in upper part of profile under the young spruce is more differentiated than in old spruce forest: the amount of quartz and kaolinite increases in upper horizon, although in this case the overall pattern of profile formation of clay material during podzolization remains unchanged. There is more substantial desilting under the birch forest, compared with profile under the spruce of same age within top 50 cm. Under the meadow vegetation we've discovered differentiation in mineral composition. Upper horizons contain smectite phase and differ from the underlying

  14. Plant traits determine the phylogenetic structure of arbuscular mycorrhizal fungal communities.

    Science.gov (United States)

    López-García, Álvaro; Varela-Cervero, Sara; Vasar, Martti; Öpik, Maarja; Barea, José M; Azcón-Aguilar, Concepción

    2017-12-01

    Functional diversity in ecosystems has traditionally been studied using aboveground plant traits. Despite the known effect of plant traits on the microbial community composition, their effects on the microbial functional diversity are only starting to be assessed. In this study, the phylogenetic structure of arbuscular mycorrhizal (AM) fungal communities associated with plant species differing in life cycle and growth form, that is, plant life forms, was determined to unravel the effect of plant traits on the functional diversity of this fungal group. The results of the 454 pyrosequencing showed that the AM fungal community composition differed across plant life forms and this effect was dependent on the soil collection date. Plants with ruderal characteristics tended to associate with phylogenetically clustered AM fungal communities. By contrast, plants with resource-conservative traits associated with phylogenetically overdispersed AM fungal communities. Additionally, the soil collected in different seasons yielded AM fungal communities with different phylogenetic dispersion. In summary, we found that the phylogenetic structure, and hence the functional diversity, of AM fungal communities is dependent on plant traits. This finding adds value to the use of plant traits for the evaluation of belowground ecosystem diversity, functions and processes. © 2017 John Wiley & Sons Ltd.

  15. Terrestrial Analogs to Mars

    Science.gov (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

    2002-08-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  16. Soil and terrestrial biology studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Soil and terrestrial biology studies focused on developing an understanding of the uptake of gaseous substances from the atmosphere by plants, biodegradation of oil, and the movement of Pu in the terrestrial ecosystems of the southeastern United States. Mathematical models were developed for SO 2 and tritium uptake from the atmosphere by plants; the uptake of tritium by soil microorganisms was measured; and the relationships among the Pu content of soil, plants, and animals of the Savannah River Plant area were studied. Preliminary results are reported for studies on the biodegradation of waste oil on soil surfaces

  17. Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond

    International Nuclear Information System (INIS)

    Farfan, E.; Jannik, T.

    2011-01-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90 Sr and 137 Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  18. Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

    Directory of Open Access Journals (Sweden)

    Jonas J Lembrechts

    Full Text Available Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

  19. Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

    Science.gov (United States)

    Lembrechts, Jonas J; Milbau, Ann; Nijs, Ivan

    2014-01-01

    Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

  20. Restructuring of endophytic bacterial communities in grapevine yellows-diseased and recovered Vitis vinifera L. plants.

    Science.gov (United States)

    Bulgari, Daniela; Casati, Paola; Crepaldi, Paola; Daffonchio, Daniele; Quaglino, Fabio; Brusetti, Lorenzo; Bianco, Piero Attilio

    2011-07-01

    Length heterogeneity-PCR assays, combined with statistical analyses, highlighted that the endophytic bacterial community associated with healthy grapevines was characterized by a greater diversity than that present in diseased and recovered plants. The findings suggest that phytoplasmas can restructure the bacterial community by selecting endophytic strains that could elicit a plant defense response.

  1. A Post Licensing Study of Community Effects at Two Operating Nuclear Power Plants. Final Report.

    Science.gov (United States)

    Purdy, Bruce J.; And Others

    In an effort to identify and assess the social, economic, and political effects of nuclear power plant construction and operation upon two host communities (Plymouth, Massachusetts and Waterford, Connecticut), a post-licensing review revealed that the primary impact of the nuclear power plants in both communities was an increase in the property…

  2. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    NARCIS (Netherlands)

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

  3. Links between plant and fungal communities across a deforestation chronosequence in the Amazon rainforest.

    Science.gov (United States)

    Mueller, Rebecca C; Paula, Fabiana S; Mirza, Babur S; Rodrigues, Jorge L M; Nüsslein, Klaus; Bohannan, Brendan J M

    2014-07-01

    Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests.

  4. Changing expectations: a longitudinal study of community attitudes toward a nuclear power plant

    International Nuclear Information System (INIS)

    Hughey, J.B.; Lounsbury, J.W.; Sundstrom, E.; Mattingly, T.J. Jr.

    1983-01-01

    Initial and 5-year follow-up interviews were conducted with 213 residents of the host community for a nuclear power plant. The purpose was to determine possible changes in attitudes toward the plant and expectations about potential outcomes associated with construction. Large negative changes in attitudes toward the plant were noted and were accompanied most notably by decreased expectations of positive outcomes. The structure of the expectations remained essentially stable over the 5-year period. Perceptions of hazards, community disruption, and economic benefits as measured early in construction and during peak construction were found to be the best predictors of acceptance of the nuclear plant. Initial expectations were found to predict overall attitude toward the plant 5 years later. Results were discussed in terms of implications for social impact assessment, large-scale community change, and the predictability of community attitudes toward nuclear power plant construction

  5. Effects of diversity and identity of the neighbouring plant community on the abundance of arthropods on individual ragwort (Jacobaea vulgaris) plants

    NARCIS (Netherlands)

    Kostenko, O.; Grootemaat, Saskia S.; Van der Putten, W.H.; Bezemer, T.M.

    2012-01-01

    The diversity of plant community can greatly affect the abundance and diversity of arthropods associated to that community, but can also influence the composition or abundance of arthropods on individual plants growing in that community. We sampled arthropods and recorded plant size of individual

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

    Science.gov (United States)

    Švamberková, Eva; Vítová, Alena; Lepš, Jan

    2017-11-01

    Differences in plant species composition between a community and its species pool are considered to reflect the effect of community filters. If we define the species pool as a set of species able to reach a site and form a viable population in a given abiotic environment (i.e. to pass the dispersal and abiotic filter), the difference in species composition should correspond to the effect of biotic interactions. However, most of the operational definitions of the species pool are based on co-occurrence patterns and thus also reflect the effect of biotic relationships, including definitions based on functional plant traits, Ellenberg indicator values or Beals index. We conducted two seed introduction experiments in an oligotrophic wet meadow with the aim of demonstrating that many species excluded, according to the above definitions, from a species pool are in fact able to establish there successfully if competition is removed. In sowing experiments, we studied the establishment and survival of species after the removal of competition (i.e. in artificial gaps) and in intact vegetation. We also investigated inter-annual variability of seed germination and seedling establishment and competitive exclusion of sown species. The investigated species also included those from very different habitats (i.e. species with very low corresponding Beals index or Ellenberg indicator values that were different from the target community weighted mean). Many of these species were able to grow in the focal wet meadow if competition was removed, but they did not establish and survive in the intact community. These species are thus not limited by abiotic conditions, but by the biotic filter. We also recorded a great inter-annual variability in seed germination and seedling establishment. Competitive exclusion of species with different ecological requirements could be quite fast (one and half seasons) in some species, but some non-resident species were able to survive several seasons; the

  7. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

    Science.gov (United States)

    Ding, Tao; Melcher, Ulrich

    2016-01-01

    Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

  8. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

    Directory of Open Access Journals (Sweden)

    Tao Ding

    Full Text Available Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

  9. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    OpenAIRE

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  10. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    OpenAIRE

    Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  11. Analytical and Radio-Histo-Chemical Experiments of Plants and Tissue Culture Cells Treated with Lunar and Terrestrial Materials

    Science.gov (United States)

    Halliwell, R. S.

    1973-01-01

    The nature and mechanisms of the apparent simulation of growth originally observed in plants growing in contact with lunar soil during the Apollo project quarantine are examined. Preliminary experiments employing neutron activated lunar soil indicate uptake of a few elements by plants. It was found that while the preliminary neutron activation technique allowed demonstration of uptake of minerals it presented numerous disadvantages for use in critical experiments directed at elucidating possible mechanisms of stimulation.

  12. Taiwan's industrial heavy metal pollution threatens terrestrial biota

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, M.J. [Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Selvaraj, K. [Institute of Marine Geology and Chemistry, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Agoramoorthy, G. [Department of Pharmacy, Tajen University, Yanpu, Pingtung 907, Taiwan (China)]. E-mail: agoram@mail.tajen.edu.tw

    2006-09-15

    The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan.

  13. Changes in uranium plant community leaders' attitudes toward nuclear power: before and after TMI

    International Nuclear Information System (INIS)

    Winfield-Laird, I.; Hastings, M.; Cawley, M.E.

    1982-01-01

    The results of an investigation of the reactions of community leaders in nuclear power plant host communities toward nuclear power following the accident at Three Mile Island (TMI) are reported. Public and private sector officials were surveyed in ten general areas covering their attitudes toward and the continued use of nuclear power as compared to other fuel types, and the reassessment of the local plant impact on different community groups and aspects of community life. Information is compared with findings from a similar study conducted with the same community leaders prior to the TMI accident. The results indicate that community leaders' attitudes remained highly favorable toward the continued use of nuclear power. Three-fourths of the sample indicated that they would probably or definitely allow the continued use of nuclear power as compared to other fuel types, and the reassessment of the local majority still view the plant presence as having a positive impact on their communities. (author)

  14. Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area

    International Nuclear Information System (INIS)

    Okkenhaug, Gudny; Zhu Yongguan; Luo Lei; Lei Ming; Li Xi; Mulder, Jan

    2011-01-01

    Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527-11,798 mg kg -1 ), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3-748 mg kg -1 ), dominated by Sb(V). Elevated concentrations in native plant species (109-4029 mg kg -1 ) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH) 6 ] 2 , controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content. - Highlights: → Antimony (Sb) in soils from an active Sb mining area is highly bioavailable. → Sb occurs mainly as Sb(V) in Sb mining impacted soils and plants. → Sb solubility in Sb mining impacted soils is governed by Ca[Sb(OH) 6 ] 2 . → Citric acid extractable Sb in plants and bioavailable Sb in soils are strongly correlated. - Antimony (Sb) in soils from an active Sb mining area is highly bioavailable and controlled by the solubility of calcium antimonate.

  15. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    International Nuclear Information System (INIS)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ 13 C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m −2 ⋅y −1 . Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the terrestrial

  16. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Junchao [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Thanh, E-mail: bswang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Han, Shanlong [Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Pu; Zhang, Qinghua; Jiang, Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ{sup 13}C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m{sup −2}⋅y{sup −1}. Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the

  17. Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure.

    Science.gov (United States)

    Busby, Posy E; Lamit, Louis J; Keith, Arthur R; Newcombe, George; Gehring, Catherine A; Whitham, Thomas G; Dirzo, Rodolfo

    2015-07-01

    Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

  18. Temporal dynamics of soil nematode communities in a grassland plant diversity experiment.

    NARCIS (Netherlands)

    Viketoft, M.; Sohlenius, B.; Bostrom, S.; Palmborg, C.; Bengtsson, J.; Berg, M.P.; Kuss-Danell, K.

    2011-01-01

    We report here on an 8-year study examining links between plant and nematode communities in a grassland plant diversity experiment, located in the north of Sweden on previous agricultural soil. The examined plots contained 1, 4 and 12 common grassland plant species from three functional groups;

  19. Long-term effects of plant diversity and composition on soil nematode communities in grassland.

    NARCIS (Netherlands)

    Viketoft, M.; Bengtsson, J.; Sohlenius, B.; Berg, M.P.; Petchey, O.; Palmborg, C.; Huss-Daniel, K.

    2009-01-01

    An important component of plant-soil feedbacks is how plant species identity and diversity influence soil organism communities. We examine the effects of grassland plant species growing alone and together up to a richness of 12 species on nematode diversity and feeding group composition, eight years

  20. Comparing arbuscular mycorrhizal communities of individual plants in a grassland biodiversity experiment

    NARCIS (Netherlands)

    Van de Voorde, T.F.J.; Van der Putten, W.H.; Gamper, H.A.; Hol, W.H.G.; Bezemer, T.M.

    2010-01-01

    Plants differ greatly in the soil organisms colonizing their roots. However, how soil organism assemblages of individual plant roots can be influenced by plant community properties remains poorly understood. We determined the composition of arbuscular mycorrhizal fungi (AMF) in Jacobaea vulgaris

  1. Fire and invasive exotic plant species in eastern oak communities: an assessment of current knowledge

    Science.gov (United States)

    Cynthia D. Huebner

    2006-01-01

    Successful regeneration of oak-dominated communities in the Eastern United States historically requires disturbance such as fire, making them vulnerable to invasion by exotic plants. Little is currently known about the effects of fire on invasive plant species and the effects of invasive plant species on fire regimes of this region. Seventeen common eastern invaders...

  2. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

    Science.gov (United States)

    Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

    2018-01-01

    Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

  3. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

    Directory of Open Access Journals (Sweden)

    Martina Janoušková

    Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

  4. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Science.gov (United States)

    Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Inoculation with arbuscular mycorrhizal fungi (AMF) may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation. PMID:28738069

  5. Litter Accumulation and Nutrient Content of Roadside Plant Communities in Sichuan Basin, China.

    Science.gov (United States)

    He, Huiqin; Monaco, Thomas

    2017-08-30

    It is widely recognized that feedbacks exist between plant litter and plant community species composition, but this relationship is difficult to interpret over heterogeneous conditions typical of modified environments such as roadways. Given the need to expedite natural recovery of disturbed areas through restoration interventions, we characterized litter accumulation and nutrient content (i.e., organic carbon, total N, and P) and quantified their association with key plant species. Plant species cover and litter characteristics were sampled at 18 successional forest plant communities along major roadways in Sichuan Basin, western China. Variation in litter across communities was assessed with principal component analysis (PCA) and species with the highest correlation to PCA axes were determined with Pearson's r coefficients. Plant communities with the longest time since road construction (i.e., 70 years) were distinctly different in litter total N and organic carbon compared to plant communities with a shorter disturbance history. We encountered 59 plant species across sampling plots, but only four rare species (i.e., frequency plant litter across heavily disturbed landscapes and how litter characteristics and rare plant species are correlated.

  6. Terrestrial magnetosphere

    International Nuclear Information System (INIS)

    Pande, D.C.; Agarwal, D.C.

    1982-01-01

    This paper presents a review about terrestrial magnetosphere. During the last few years considerable investigation have been carried out about the properties of Solar Wind and its interaction with planetary magnetic fields. It is therefore of high importance to accumulate all the investigations in a comprehensive form. The paper reviews the property of earth's magnetosphere, magnetosheath, magneto pause, polar cusps, bow shook and plasma sheath. (author)

  7. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    Directory of Open Access Journals (Sweden)

    Richard R Rodrigues

    Full Text Available The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum, another by a shrub (Rhamnus davurica, and the third by a tree (Ailanthus altissima. The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME. Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that

  8. Aquatic and Terrestrial Environment 2004

    DEFF Research Database (Denmark)

    Andersen, J. M.; Boutrup, S.; Bijl, L. van der

    This report presents the 2004 results of the Danish National Monitoring and Assess-ment Programme for the Aquatic and Terrestrial Environments (NOVANA). 2004 was the first year in which terrestrial nature was included in the monitoring pro-gramme. The report reviews the state of the groundwater......, watercourses, lakes and marine waters and the pressures upon them and reviews the monitoring of terrestrial natural habitats and selected plants and animals. The report is based on the annual reports prepared for each subprogramme by the Topic Centres. The latter reports are mainly based on data collected...

  9. Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient.

    NARCIS (Netherlands)

    Notten, M.J.M.; Oosthoek, A.; Rozema, J.; Aerts, R.

    2005-01-01

    We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations

  10. Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, Derris scandens (Dicotyledonae:Leguminocae)

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Sonak, S.; Garg

    between 200 to 300 mu g.ml sup(-1), whereas, the bacterial inhibition zone around the disc containing about 600-800 mu g of extract ranged between 1-5 mm. The results suggest that the crude extract of the plant is nontoxic and possesses both antibacterial...

  11. Engineer pioneer plants respond to and affect geomorphic constraints similarly along water–terrestrial interfaces world-wide

    OpenAIRE

    Corenblit, D.; Baas, A.; Balke, T.; Bouma, T.J.; Fromard, F.; Garófano-Gómez, V.; González, E.; Gurnell, A.M.; Hortobágyi, B.; Julien, F.; Kim, D.; Lambs, L.; Stallins, J.A.; Steiger, J.; Tabacchi, E.

    2015-01-01

    Aim Within fluvial and coastal ecosystems world-wide, flows of water, wind and sediment generate a shifting landscape mosaic composed of bare substrate and pioneer and mature vegetation successional stages. Pioneer plant species that colonize these ecosystems at the land–water interface have developed specific traits in response to environmental constraints (response...

  12. Litter Accumulation and Nutrient Content of Roadside Plant Communities in Sichuan Basin, China

    OpenAIRE

    He, Huiqin; Monaco, Thomas

    2017-01-01

    It is widely recognized that feedbacks exist between plant litter and plant community species composition, but this relationship is difficult to interpret over heterogeneous conditions typical of modified environments such as roadways. Given the need to expedite natural recovery of disturbed areas through restoration interventions, we characterized litter accumulation and nutrient content (i.e., organic carbon, total N, and P) and quantified their association with key plant species. Plant spe...

  13. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities

    OpenAIRE

    Uddin, Md Nazim; Robinson, Randall William

    2017-01-01

    Background Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in ...

  14. Bottom-up and top-down effects on plant communities

    DEFF Research Database (Denmark)

    Souza, Lara; Zelikova, Tamara Jane; Sanders, Nate

    2016-01-01

    -down) and soil nitrogen (bottom-up) were manipulated over six years in an existing old-field community. We tracked plant α and β diversity - within plot richness and among plot biodiversity- and aboveground net primary productivity (ANPP) over the course of the experiment. We found that bottom-up factors...... affected ANPP while top-down factors influenced plant community structure. Across years, while N reduction lowered ANPP by 10%, N reduction did not alter ANPP relative to control plots. Further, N reduction lowered ANPP by 20% relative to N addition plots. On the other hand, the reduction of insect...... community composition via shifts in plant dominance....

  15. Long-term Hg pollution-induced structural shifts of bacterial community in the terrestrial isopod (Porcellio scaber) gut

    Energy Technology Data Exchange (ETDEWEB)

    Lapanje, Ales, E-mail: ales@ifb.s [Institute of Physical Biology, Ljubljana (Slovenia); Zrimec, Alexis [Institute of Physical Biology, Ljubljana (Slovenia); Drobne, Damjana [Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana (Slovenia); Rupnik, Maja [Institute of Public Health Maribor, Maribor (Slovenia)

    2010-10-15

    In previous studies we detected lower species richness and lower Hg sensitivity of the bacteria present in egested guts of Porcellio scaber (Crustacea, Isopoda) from chronically Hg polluted than from unpolluted environment. Basis for such results were further investigated by sequencing of 16S rRNA genes of mercury-resistant (Hg{sup r}) isolates and clone libraries. We observed up to 385 times higher numbers of Hg{sup r} bacteria in guts of animals from polluted than from unpolluted environment. The majority of Hg{sup r} strains contained merA genes. Sequencing of 16S rRNA clones from egested guts of animals from Hg-polluted environments showed elevated number of bacteria from Pseudomonas, Listeria and Bacteroidetes relatives groups. In animals from pristine environment number of bacteria from Achromobacter relatives, Alcaligenes, Paracoccus, Ochrobactrum relatives, Rhizobium/Agrobacterium, Bacillus and Microbacterium groups were elevated. Such bacterial community shifts in guts of animals from Hg-polluted environment could significantly contribute to P. scaber Hg tolerance. - Chronic environmental mercury pollution induces bacterial community shifts and presence of elevated number as well as increased diversity of Hg-resistant bacteria in guts of isopods.

  16. Long-term Hg pollution-induced structural shifts of bacterial community in the terrestrial isopod (Porcellio scaber) gut

    International Nuclear Information System (INIS)

    Lapanje, Ales; Zrimec, Alexis; Drobne, Damjana; Rupnik, Maja

    2010-01-01

    In previous studies we detected lower species richness and lower Hg sensitivity of the bacteria present in egested guts of Porcellio scaber (Crustacea, Isopoda) from chronically Hg polluted than from unpolluted environment. Basis for such results were further investigated by sequencing of 16S rRNA genes of mercury-resistant (Hg r ) isolates and clone libraries. We observed up to 385 times higher numbers of Hg r bacteria in guts of animals from polluted than from unpolluted environment. The majority of Hg r strains contained merA genes. Sequencing of 16S rRNA clones from egested guts of animals from Hg-polluted environments showed elevated number of bacteria from Pseudomonas, Listeria and Bacteroidetes relatives groups. In animals from pristine environment number of bacteria from Achromobacter relatives, Alcaligenes, Paracoccus, Ochrobactrum relatives, Rhizobium/Agrobacterium, Bacillus and Microbacterium groups were elevated. Such bacterial community shifts in guts of animals from Hg-polluted environment could significantly contribute to P. scaber Hg tolerance. - Chronic environmental mercury pollution induces bacterial community shifts and presence of elevated number as well as increased diversity of Hg-resistant bacteria in guts of isopods.

  17. Relative Importance and Knowledge Distribution of Medicinal Plants in a Kichwa Community in the Ecuadorian Amazon

    Directory of Open Access Journals (Sweden)

    Brian Joseph Doyle

    2017-01-01

    Full Text Available Traditional knowledge, such as knowledge of the use of plants as medicine, influences how indigenous people manage forest resources. Gender and age-associated differences in traditional knowledge may impact forest resource management because of the traditional division of labor. We interviewed 18 men and 18 women between 9 and 74 years old in San José de Payamino, an indigenous community of the Kichwa ethnicity in the Ecuadorian Amazon, to determine if there are gender or age-associated differences in medicinal plant knowledge among the Payamino people and to identify the most important species from a sample of medicinal plants. Individuals were interviewed using a tablet that displayed images of 34 plants, which had been cited by traditional healers in the community. Quantitative analysis provided insight into the relative importance of plants in the sample as well as the distribution of medicinal plant knowledge among members of the community. The most important plants were Tradescantia zanonia and Monolena primuliflora. These plants should be considered candidates for further investigation. There was a positive correlation between age and knowledge of medicinal plants, but no significant difference between genders. Our results suggest that an interview method that relies on digital images can reveal differences in the importance of medicinal plants as well as provide insight into the distribution of traditional medical knowledge. While men and women are likely to manage forest resources similarly, younger members of the community may not have the same regard for forest resources as their elder counterparts.

  18. Determination of heavy toxic metals in the environment indicator specimens (water, river sediment and kangkung plant) of Muria terrestrial

    International Nuclear Information System (INIS)

    J Djati Pramana; Sukirno; Bambang Irianto

    2004-01-01

    Analysis and evaluation contain of heavy toxic metals in the water kangkung plant (Ipomea reptans poir) and river sediment of five rivers sampling location at peninsula Muria region by NAA Instrumental method has been done. The method of sampling. preparation although analysis method according to standard procedure of environmental specimens analysis. Accordingly the quality standard of water group C although group D. the sample from fifth river location sampling was under allowed maximum Cd concentration. Correlation between variable location and kind of indicators to heavy metal concentration was shown by coefficient of Pearson correlation. Interpretation by statistic correlation was obtained. Correlation between kind indicators was indicated that river water has significant correlation with the kangkung plant about Cd concentration. (author)

  19. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species ( Solidago canadensis, Populus balsamifera , and Lycopus europaeus ) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  20. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Directory of Open Access Journals (Sweden)

    Bachir Iffis

    2017-08-01

    Full Text Available Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate

  1. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  2. Assessing plant community composition fails to capture impacts of white-tailed deer on native and invasive plant species.

    Science.gov (United States)

    Nuzzo, Victoria; Dávalos, Andrea; Blossey, Bernd

    2017-07-01

    Excessive herbivory can have transformative effects on forest understory vegetation, converting diverse communities into depauperate ones, often with increased abundance of non-native plants. White-tailed deer are a problematic herbivore throughout much of eastern North America and alter forest understory community structure. Reducing (by culling) or eliminating (by fencing) deer herbivory is expected to return understory vegetation to a previously diverse condition. We examined this assumption from 1992 to 2006 at Fermilab (Batavia, IL) where a cull reduced white-tailed deer ( Odocoileus virginianus ) abundance in 1998/1999 by 90 % from 24.6 to 2.5/km 2 , and at West Point, NY, where we assessed interactive effects of deer, earthworms, and invasive plants using 30 × 30 m paired fenced and open plots in 12 different forests from 2009 to 2012. We recorded not only plant community responses (species presence and cover) within 1 m 2 quadrats, but also responses of select individual species (growth, reproduction). At Fermilab, introduced Alliaria petiolata abundance initially increased as deer density increased, but then declined after deer reduction. The understory community responded to the deer cull by increased cover, species richness and height, and community composition changed but was dominated by early successional native forbs. At West Point plant community composition was affected by introduced earthworm density but not deer exclusion. Native plant cover increased and non-native plant cover decreased in fenced plots, thus keeping overall plant cover similar. At both sites native forb cover increased in response to deer reduction, but the anticipated response of understory vegetation failed to materialize at the community level. Deer-favoured forbs ( Eurybia divaricata , Maianthemum racemosum , Polygonatum pubescens and Trillium recurvatum ) grew taller and flowering probability increased in the absence of deer. Plant community monitoring fails to capture

  3. Distribution of ether lipids and composition of the archaeal community in terrestrial geothermal springs: impact of environmental variables.

    Science.gov (United States)

    Xie, Wei; Zhang, Chuanlun L; Wang, Jinxiang; Chen, Yufei; Zhu, Yuanqing; de la Torre, José R; Dong, Hailiang; Hartnett, Hilairy E; Hedlund, Brian P; Klotz, Martin G

    2015-05-01

    Archaea can respond to changes in the environment by altering the composition of their membrane lipids, for example, by modification of the abundance and composition of glycerol dialkyl glycerol tetraethers (GDGTs). Here, we investigated the abundance and proportions of polar GDGTs (P-GDGTs) and core GDGTs (C-GDGTs) sampled in different seasons from Tengchong hot springs (Yunnan, China), which encompassed a pH range of 2.5-10.1 and a temperature range of 43.7-93.6°C. The phylogenetic composition of the archaeal community (reanalysed from published work) divided the Archaea in spring sediment samples into three major groups that corresponded with spring pH: acidic, circumneutral and alkaline. Cluster analysis showed correlation between spring pH and the composition of P- and C-GDGTs and archaeal 16S rRNA genes, indicating an intimate link between resident Archaea and the distribution of P- and C-GDGTs in Tengchong hot springs. The distribution of GDGTs in Tengchong springs was also significantly affected by temperature; however, the relationship was weaker than with pH. Analysis of published datasets including samples from Tibet, Yellowstone and the US Great Basin hot springs revealed a similar relationship between pH and GDGT content. Specifically, low pH springs had higher concentrations of GDGTs with high numbers of cyclopentyl rings than neutral and alkaline springs, which is consistent with the predominance of high cyclopentyl ring-characterized Sulfolobales and Thermoplasmatales present in some of the low pH springs. Our study suggests that the resident Archaea in these hot springs are acclimated if not adapted to low pH by their genetic capacity to effect the packing density of their membranes by increasing cyclopentyl rings in GDGTs at the rank of community. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession

    Directory of Open Access Journals (Sweden)

    Joseph E. Knelman

    2018-02-01

    Full Text Available Past research demonstrating the importance plant–microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder to late successional Picea sitchensis (Sitka spruce in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant–microbe interactions with late-successional plants and interspecific plant interactions more generally.

  5. Is fire exclusion in mountain big sagebrush communities prudent? Soil nutrient, plant diversity, and arthropod response to burning

    Science.gov (United States)

    Fire has largely been excluded from many mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) communities. Land and wildlife managers are especially reluctant to reintroduce fire in mountain big sagebrush plant communities, especially those communities without significan...

  6. Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

    Science.gov (United States)

    2017-01-01

    We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants. PMID:28717591

  7. Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

    Directory of Open Access Journals (Sweden)

    Azucena Canto

    2017-07-01

    Full Text Available We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

  8. Evolutionary history of callose synthases in terrestrial plants with emphasis on proteins involved in male gametophyte development

    Czech Academy of Sciences Publication Activity Database

    Záveská Drábková, Lenka; Honys, David

    2017-01-01

    Roč. 12, č. 11 (2017), č. článku e0187331. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA15-16050S; GA ČR(CZ) GA17-23183S Institutional support: RVO:61389030 Keywords : exine pattern-formation * pollen wall pattern * arabidopsis-thaliana * nicotiana-tabacum * gene-expression * transcriptome analysis * male-fertility * udp-glucose * family * diversification Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 2.806, year: 2016

  9. Working group 4: Terrestrial

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A working group at a Canada/USA symposium on climate change and the Arctic identified major concerns and issues related to terrestrial resources. The group examined the need for, and the means of, involving resource managers and users at local and territorial levels in the process of identifying and examining the impacts and consequences of climatic change. Climatic change will be important to the Arctic because of the magnitude of the change projected for northern latitudes; the apparent sensitivity of its terrestrial ecosystems, natural resources, and human support systems; and the dependence of the social, cultural, and economic welfare of Arctic communities, businesses, and industries on the health and quality of their environment. Impacts of climatic change on the physical, biological, and associated socio-economic environment are outlined. Gaps in knowledge needed to quantify these impacts are listed along with their relationships with resource management. Finally, potential actions for response and adaptation are presented

  10. Notification: Hotline Complaint – Drinking Water Treatment Plant at the Fort Belknap Indian Community

    Science.gov (United States)

    Project #OA-FY13-0076, November 13, 2012. On March 22, 2012, the Office of Inspector General (OIG) received a hotline complaint on the construction of the Drinking Water Treatment Plant (DWTP) at the Fort Belknap Indian Community.

  11. Large grazers modify effects of aboveground-belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Geuverink, Elzemiek; Olff, Han; Schmid, Bernhard

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  12. Large grazers modify effects of aboveground–belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Geuverink, E.; Olff, H.

    2012-01-01

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  13. Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

    DEFF Research Database (Denmark)

    Pellissier, Loïc; Wisz, Mary S.; Strandberg, Beate

    2014-01-01

    on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase in nitrogen promoted an increase in the average specific leaf area and canopy...... height at the community level, but an increase in glyphosate promoted a decrease in those traits. Phylogenetic diversity of plant communities increased when herbicide and fertilizer were applied together, likely because functional traits facilitating plant success in those conditions were......Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based...

  14. The Community's research and development programme on decommissioning of nuclear power plants

    International Nuclear Information System (INIS)

    1982-01-01

    The programme, adopted by the Council of the European Communities, seeks to promote a number of research and development projects as well as the identification of guiding principles. The projects concern the following subjects: long-term integrity of buildings and systems; decontaminations for decommissioning purposes; dismantling techniques; treatment of specific waste materials (steel, concrete and graphite); large transport containers for radioactive waste arising from decommissioning of nuclear power plants in the Community; and influence of nuclear power plant design features on decommissioning

  15. Relationships between phyllosphere bacterial communities and plant functional traits in a neotropical forest

    Science.gov (United States)

    Kembel, Steven W.; O’Connor, Timothy K.; Arnold, Holly K.; Hubbell, Stephen P.; Wright, S. Joseph; Green, Jessica L.

    2014-01-01

    The phyllosphere—the aerial surfaces of plants, including leaves—is a ubiquitous global habitat that harbors diverse bacterial communities. Phyllosphere bacterial communities have the potential to influence plant biogeography and ecosystem function through their influence on the fitness and function of their hosts, but the host attributes that drive community assembly in the phyllosphere are poorly understood. In this study we used high-throughput sequencing to quantify bacterial community structure on the leaves of 57 tree species in a neotropical forest in Panama. We tested for relationships between bacterial communities on tree leaves and the functional traits, taxonomy, and phylogeny of their plant hosts. Bacterial communities on tropical tree leaves were diverse; leaves from individual trees were host to more than 400 bacterial taxa. Bacterial communities in the phyllosphere were dominated by a core microbiome of taxa including Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria, and Sphingobacteria. Host attributes including plant taxonomic identity, phylogeny, growth and mortality rates, wood density, leaf mass per area, and leaf nitrogen and phosphorous concentrations were correlated with bacterial community structure on leaves. The relative abundances of several bacterial taxa were correlated with suites of host plant traits related to major axes of plant trait variation, including the leaf economics spectrum and the wood density–growth/mortality tradeoff. These correlations between phyllosphere bacterial diversity and host growth, mortality, and function suggest that incorporating information on plant–microbe associations will improve our ability to understand plant functional biogeography and the drivers of variation in plant and ecosystem function. PMID:25225376

  16. Effects of migratory geese on plant communities of an Alaskan salt marsh

    Science.gov (United States)

    Zacheis, Amy B.; Hupp, Jerry W.; Ruess, Roger W.

    2001-01-01

    1. We studied the effects of lesser snow geese (Anser caerulescens caerulescens) and Canada geese (Branta canadensis) on two salt marsh plant communities in Cook Inlet, Alaska, a stopover area used during spring migration. From 1995 to 1997 we compared plant species composition and biomass on plots where geese were excluded from feeding with paired plots where foraging could occur. 2. Foraging intensity was low (650-1930 goose-days km-2) compared to other goose-grazing systems. 3. Canada geese fed mainly on above-ground shoots of Triglochin maritimum, Puccinellia spp. and Carex ramenskii, whereas the majority of the snow goose diet consisted of below-ground tissues of Plantago maritima and Triglochin maritimum. 4. Plant communities responded differently to goose herbivory. In the sedge meadow community, where feeding was primarily on above-ground shoots, there was no effect of grazing on the dominant species Carex ramenskii and Triglochin maritimum. In the herb meadow community, where snow geese fed on Plantago maritima roots and other below-ground tissues, there was a difference in the relative abundance of plant species between treatments. Biomass of Plantago maritima and Potentilla egedii was lower on grazed plots compared with exclosed, whereas biomass of Carex ramenskii was greater on grazed plots. There was no effect of herbivory on total standing crop biomass in either community. The variable effect of herbivory on Carex ramenskii between communities suggests that plant neighbours and competitive interactions are important factors in a species' response to herbivory. In addition, the type of herbivory (above- or below-ground) was important in determining plant community response to herbivory. 5. Litter accumulation was reduced in grazed areas compared with exclosed in both communities. Trampling of the previous year's litter into the soil surface by geese incorporated more litter into soils in grazed areas. 6. This study illustrates that even light herbivore

  17. A synthesis of terrestrial mercury in the western United States: Spatial distribution defined by land cover and plant productivity

    Science.gov (United States)

    Obrist, Daniel; Pearson, Christopher; Webster, Jackson; Kane, Tyler J.; Lin, Che-Jen; Aiken, George R.; Alpers, Charles N.

    2016-01-01

    A synthesis of published vegetation mercury (Hg) data across 11 contiguous states in the western United States showed that aboveground biomass concentrations followed the order: leaves (26 μg kg− 1) ~ branches (26 μg kg− 1) > bark (16 μg kg− 1) > bole wood (1 μg kg− 1). No spatial trends of Hg in aboveground biomass distribution were detected, which likely is due to very sparse data coverage and different sampling protocols. Vegetation data are largely lacking for important functional vegetation types such as shrubs, herbaceous species, and grasses.Soil concentrations collected from the published literature were high in the western United States, with 12% of observations exceeding 100 μg kg− 1, reflecting a bias toward investigations in Hg-enriched sites. In contrast, soil Hg concentrations from a randomly distributed data set (1911 sampling points; Smith et al., 2013a) averaged 24 μg kg− 1 (A-horizon) and 22 μg kg− 1 (C-horizon), and only 2.6% of data exceeded 100 μg kg− 1. Soil Hg concentrations significantly differed among land covers, following the order: forested upland > planted/cultivated > herbaceous upland/shrubland > barren soils. Concentrations in forests were on average 2.5 times higher than in barren locations. Principal component analyses showed that soil Hg concentrations were not or weakly related to modeled dry and wet Hg deposition and proximity to mining, geothermal areas, and coal-fired power plants. Soil Hg distribution also was not closely related to other trace metals, but strongly associated with organic carbon, precipitation, canopy greenness, and foliar Hg pools of overlying vegetation. These patterns indicate that soil Hg concentrations are related to atmospheric deposition and reflect an overwhelming influence of plant productivity — driven by water availability — with productive landscapes showing high soil Hg accumulation and unproductive barren soils and shrublands

  18. Thermodynamic limits set relevant constraints to the soil-plant-atmosphere system and to optimality in terrestrial vegetation

    Science.gov (United States)

    Kleidon, Axel; Renner, Maik

    2016-04-01

    The soil-plant-atmosphere system is a complex system that is strongly shaped by interactions between the physical environment and vegetation. This complexity appears to demand equally as complex models to fully capture the dynamics of the coupled system. What we describe here is an alternative approach that is based on thermodynamics and which allows for comparatively simple formulations free of empirical parameters by assuming that the system is so complex that its emergent dynamics are only constrained by the thermodynamics of the system. This approach specifically makes use of the second law of thermodynamics, a fundamental physical law that is typically not being considered in Earth system science. Its relevance to land surface processes is that it fundamentally sets a direction as well as limits to energy conversions and associated rates of mass exchange, but it requires us to formulate land surface processes as thermodynamic processes that are driven by energy conversions. We describe an application of this approach to the surface energy balance partitioning at the diurnal scale. In this application the turbulent heat fluxes of sensible and latent heat are described as the result of a convective heat engine that is driven by solar radiative heating of the surface and that operates at its thermodynamic limit. The predicted fluxes from this approach compare very well to observations at several sites. This suggests that the turbulent exchange fluxes between the surface and the atmosphere operate at their thermodynamic limit, so that thermodynamics imposes a relevant constraint to the land surface-atmosphere system. Yet, thermodynamic limits do not entirely determine the soil-plant-atmosphere system because vegetation affects these limits, for instance by affecting the magnitude of surface heating by absorption of solar radiation in the canopy layer. These effects are likely to make the conditions at the land surface more favorable for photosynthetic activity

  19. Burn Severity Dominates Understory Plant Community Response to Fire in Xeric Jack Pine Forests

    Directory of Open Access Journals (Sweden)

    Bradley D. Pinno

    2016-04-01

    Full Text Available Fire is the most common disturbance in northern boreal forests, and large fires are often associated with highly variable burn severities across the burnt area. We studied the understory plant community response to a range of burn severities and pre-fire stand age four growing seasons after the 2011 Richardson Fire in xeric jack pine forests of northern Alberta, Canada. Burn severity had the greatest impact on post-fire plant communities, while pre-fire stand age did not have a significant impact. Total plant species richness and cover decreased with disturbance severity, such that the greatest richness was in low severity burns (average 28 species per 1-m2 quadrat and plant cover was lowest in the high severity burns (average 16%. However, the response of individual plant groups differed. Lichens and bryophytes were most common in low severity burns and were effectively eliminated from the regenerating plant community at higher burn severities. In contrast, graminoid cover and richness were positively related to burn severity, while forbs did not respond significantly to burn severity, but were impacted by changes in soil chemistry with increased cover at pH >4.9. Our results indicate the importance of non-vascular plants to the overall plant community in this harsh environment and that the plant community is environmentally limited rather than recruitment or competition limited, as is often the case in more mesic forest types. If fire frequency and severity increase as predicted, we may see a shift in plant communities from stress-tolerant species, such as lichens and ericaceous shrubs, to more colonizing species, such as certain graminoids.

  20. Rapid plant evolution in the presence of an introduced species alters community composition.

    Science.gov (United States)

    Smith, David Solance; Lau, Matthew K; Jacobs, Ryan; Monroy, Jenna A; Shuster, Stephen M; Whitham, Thomas G

    2015-10-01

    Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities. Here, we use a common garden design that addresses and supports two hypotheses. First, native S. velutina has rapidly evolved in the presence of introduced elk. We found that plants originating from sites with introduced elk flowered nearly 3 weeks before plants originating from sites without elk. Second, evolution of S. velutina results in a change to the plant-associated arthropod community. We found that plants originating from sites with introduced elk supported an arthropod community that had ~35 % fewer total individuals and a different species composition. Our results show that the impacts of introduced species can have both ecological and evolutionary consequences for strongly interacting species that subsequently cascade to affect a much larger community. Such evolutionary consequences are likely to be long-term and difficult to remediate.

  1. Does a decade of elevated [CO2] affect a desert perennial plant community?

    Science.gov (United States)

    Newingham, Beth A; Vanier, Cheryl H; Kelly, Lauren J; Charlet, Therese N; Smith, Stanley D

    2014-01-01

    Understanding the effects of elevated [CO2 ] on plant community structure is crucial to predicting ecosystem responses to global change. Early predictions suggested that productivity in deserts would increase via enhanced water-use efficiency under elevated [CO2], but the response of intact arid plant communities to elevated [CO2 ] is largely unknown. We measured changes in perennial plant community characteristics (cover, species richness and diversity) after 10 yr of elevated [CO2] exposure in an intact Mojave Desert community at the Nevada Desert Free-Air CO2 Enrichment (FACE) Facility. Contrary to expectations, total cover, species richness, and diversity were not affected by elevated [CO2]. Over the course of the experiment, elevated [CO2] had no effect on changes in cover of the evergreen C3 shrub, Larrea tridentata; alleviated decreases in cover of the C4 bunchgrass, Pleuraphis rigida; and slightly reduced the cover of C3 drought-deciduous shrubs. Thus, we generally found no effect of elevated [CO2] on plant communities in this arid ecosystem. Extended drought, slow plant growth rates, and highly episodic germination and recruitment of new individuals explain the lack of strong perennial plant community shifts after a decade of elevated [CO2]. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  2. Seed bank and big sagebrush plant community composition in a range margin for big sagebrush

    Science.gov (United States)

    Martyn, Trace E.; Bradford, John B.; Schlaepfer, Daniel R.; Burke, Ingrid C.; Laurenroth, William K.

    2016-01-01

    The potential influence of seed bank composition on range shifts of species due to climate change is unclear. Seed banks can provide a means of both species persistence in an area and local range expansion in the case of increasing habitat suitability, as may occur under future climate change. However, a mismatch between the seed bank and the established plant community may represent an obstacle to persistence and expansion. In big sagebrush (Artemisia tridentata) plant communities in Montana, USA, we compared the seed bank to the established plant community. There was less than a 20% similarity in the relative abundance of species between the established plant community and the seed bank. This difference was primarily driven by an overrepresentation of native annual forbs and an underrepresentation of big sagebrush in the seed bank compared to the established plant community. Even though we expect an increase in habitat suitability for big sagebrush under future climate conditions at our sites, the current mismatch between the plant community and the seed bank could impede big sagebrush range expansion into increasingly suitable habitat in the future.

  3. Community-Weighted Mean Plant Traits Predict Small Scale Distribution of Insect Root Herbivore Abundance.

    Directory of Open Access Journals (Sweden)

    Ilja Sonnemann

    Full Text Available Small scale distribution of insect root herbivores may promote plant species diversity by creating patches of different herbivore pressure. However, determinants of small scale distribution of insect root herbivores, and impact of land use intensity on their small scale distribution are largely unknown. We sampled insect root herbivores and measured vegetation parameters and soil water content along transects in grasslands of different management intensity in three regions in Germany. We calculated community-weighted mean plant traits to test whether the functional plant community composition determines the small scale distribution of insect root herbivores. To analyze spatial patterns in plant species and trait composition and insect root herbivore abundance we computed Mantel correlograms. Insect root herbivores mainly comprised click beetle (Coleoptera, Elateridae larvae (43% in the investigated grasslands. Total insect root herbivore numbers were positively related to community-weighted mean traits indicating high plant growth rates and biomass (specific leaf area, reproductive- and vegetative plant height, and negatively related to plant traits indicating poor tissue quality (leaf C/N ratio. Generalist Elaterid larvae, when analyzed independently, were also positively related to high plant growth rates and furthermore to root dry mass, but were not related to tissue quality. Insect root herbivore numbers were not related to plant cover, plant species richness and soil water content. Plant species composition and to a lesser extent plant trait composition displayed spatial autocorrelation, which was not influenced by land use intensity. Insect root herbivore abundance was not spatially autocorrelated. We conclude that in semi-natural grasslands with a high share of generalist insect root herbivores, insect root herbivores affiliate with large, fast growing plants, presumably because of availability of high quantities of food. Affiliation of

  4. Comparison of bacterial and fungal communities between natural and planted pine forests in subtropical China.

    Science.gov (United States)

    Nie, Ming; Meng, Han; Li, Ke; Wan, Jia-Rong; Quan, Zhe-Xue; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

    2012-01-01

    To improve our understanding of the changes in bacterial and fungal diversity in natural pine and planted forests in subtropical region of China, we examined bacterial and fungal communities from a native and a nearby planted pine forest of the Mt. Lushan by constructing clone libraries of 16S and 18S rRNA genes. For bacterial communities, Proteobacteria and Acidobacteria were dominant bacterial taxa in both two types of forest soils. The Shannon-Wiener diversity index, rarefaction curve analysis, and LibShuff analysis suggest that these two forests contained similar diversity of bacterial communities. Low soil acidity (pH ≈ 4) of our study forests might be one of the most important selection factors determining growth of acidophilic Acidobacteria and Proteobacteria. However, the natural forest harbored greater level of fungal diversity than the planted forest according to the Shannon-Wiener diversity index and rarefaction curve analysis. Basidiomycota and Ascomycota were dominant fungal taxa in the soils of natural and planted forests, respectively. Our results suggest that fungal community was more sensitive than the bacterial community in characterizing the differences in plant cover impacts on the microbial flora in the natural and planted forests. The natural and planted forests may function differently due to the differences in soil fungal diversity and relative abundance.

  5. Plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense.

    Science.gov (United States)

    Mooney, Kailen A; Agrawal, Anurag A

    2008-06-01

    Little is known about the mechanisms by which plant genotype shapes arthropod community structure. In a field experiment, we measured the effects of milkweed (Asclepias syriaca) genotype and ants on milkweed arthropods. Populations of the ant-tended aphid Aphis asclepiadis and the untended aphid Myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. There was no milkweed effect on predatory arthropods. Ants increased Aphis abundance 59%, decreased Myzocallis abundance 52%, and decreased predator abundance 56%. Milkweed genotype indirectly influenced ants via direct effects on Aphis and Myzocallis abundance. Milkweed genotype also modified ant-aphid interactions, influencing the number of ants attracted per Aphis and Myzocallis. While ant effects on Myzocallis were consistently negative, effects on Aphis ranged from antagonistic to mutualistic among milkweed genotypes. As a consequence of milkweed effects on ant-aphid interactions, ant abundance varied 13-fold among milkweed genotypes, and monarch caterpillar survival was negatively correlated with genetic variation in ant abundance. We speculate that heritable variation in milkweed phloem sap drives these effects on aphids, ants, and caterpillars. In summary, milkweed exerts genetic control over the interactions between aphids and an ant that provides defense against foliage-feeding caterpillars.

  6. Species richness and floristic composition of Choco Region plant communities Species richness and floristic composition of Choco Region plant communities

    Directory of Open Access Journals (Sweden)

    Gentry Alwyn H.

    1986-12-01

    Full Text Available The Chocó phytogeographical region of coastal Colombia and adjacent Ecuador is well known as a region of unusually high endemism in plants (GENTRY, 1982a, 1986b, birds (TERBORGH & WINTER, 1982, and butterflies (BROWN, 1975, 1982. The region is also reputed to be unusually diverse biologically (GENTRY, 1978, 1982a but much of the data base for this assumption is rather anecdotal and for birds and heliconiinae butterflies (probably the best known groups of organisms it is clear that faunistic community diversity of the coastal Chocó is substantially less than in much of upper Amazonia (J. TERBORGH, pers. comm., K. BROWN, pers. comm.. El Choco la región fitogeográfica de la costa de Colombia y adyacente al Ecuador es conocido como una región de inusualmente alto endemismo en plantas (Gentry, 1982a, 1986b, pájaros (Terborgh y Winter, 1982, y las mariposas (Brown, 1975, 1982. La región también es conocida por ser inusualmente diversa biológicamente (Gentry, 1978, 1982a, pero gran parte de la base de datos para estesuposición es bastante anecdótico y para las aves y mariposas Heliconiinae (prooably los grupos más conocidos de organismos, está claro que la diversidad faunística comunidad del Chaco costera es sustancialmente menor que en gran parte de la Amazonia superior (J. Terborgh, com. pers., K . BROWN, com. pers..El único dato de nivel comunitario disponible para las plantas de la costa Colombia es la forma incompleta analizado 1000 m2 muestra de todas las plantas de más de2.5 cm dbh procedente de Tutunendó, incluido en Gentry (1982b de los patrones de diversidad neotropicales. Choco muestra de Gentry tenía el más alto número de especies de una serie de sitios de muestra y similares que llegaron a la conclusión de que nivel de riqueza de especies vegetales comunidad aumenta directamente con la precipitación. Muchos 1.000 m2 adicionales están disponibles, tanto desde el Chocoregión y de las especies ricas en bosques de Alto

  7. Purple pitcher plant (Sarracenia rosea Dieback and partial community disassembly following experimental storm surge in a coastal pitcher plant bog.

    Directory of Open Access Journals (Sweden)

    Matthew J Abbott

    Full Text Available Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment. There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change.

  8. Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

    Czech Academy of Sciences Publication Activity Database

    Krüger, C.; Kohout, Petr; Janoušková, M.; Püschel, D.; Frouz, J.; Rydlová, J.

    2017-01-01

    Roč. 8, APR 20 (2017), s. 1-16, č. článku 719. ISSN 1664-302X Institutional support: RVO:61388971 Keywords : biodiversity * community ecology * fungal and plant succession Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.076, year: 2016

  9. Earthworms drive succession of both plant and Collembola communities in post-mining sites

    Czech Academy of Sciences Publication Activity Database

    Mudrák, Ondřej; Uteseny, Karoline; Frouz, Jan

    2016-01-01

    Roč. 18, April (2016), EGU2016-8464 ISSN 1607-7962. [European Geosciences Union General Assembly 2016. 17.04.2016-22.04.2016, Vienna] Institutional support: RVO:60077344 ; RVO:67985939 Keywords : earthworms * succession * plant communities * Collembola communities * post-mining sites Subject RIV: DF - Soil Science

  10. Global environmental change effects on plant community composition trajectories depend upon management legacies

    NARCIS (Netherlands)

    Perring, Michael P.; Bernhardt-Römermann, Markus; Baeten, Lander; Midolo, Gabriele; Blondeel, Haben; Depauw, Leen; Landuyt, Dries; Maes, Sybryn L.; Lombaerde, De Emiel; Carón, Maria Mercedes; Vellend, Mark; Brunet, Jörg; Chudomelová, Markéta; Decocq, Guillaume; Diekmann, Martin; Dirnböck, Thomas; Dörfler, Inken; Durak, Tomasz; Frenne, De Pieter; Gilliam, Frank S.; Hédl, Radim; Heinken, Thilo; Hommel, Patrick; Jaroszewicz, Bogdan; Kirby, Keith J.; Kopecký, Martin; Lenoir, Jonathan; Li, Daijiang; Máliš, František; Mitchell, Fraser J.G.; Naaf, Tobias; Newman, Miles; Petřík, Petr; Reczyńska, Kamila; Schmidt, Wolfgang; Standovár, Tibor; Świerkosz, Krzysztof; Calster, Van Hans; Vild, Ondřej; Wagner, Eva Rosa; Wulf, Monika; Verheyen, Kris

    2018-01-01

    The contemporary state of functional traits and species richness in plant communities depends on legacy effects of past disturbances. Whether temporal responses of community properties to current environmental changes are altered by such legacies is, however, unknown. We expect global environmental

  11. Effects of changes in plant species richness and community traits on carabid assemblages and feeding guilds

    NARCIS (Netherlands)

    Harvey, J.A.; Putten, van der W.H.; Turin, H.; Wagenaar, R.; Bezemer, T.M.

    2008-01-01

    Experiments were conducted between 2001 and 2003 in constructed plant communities that were set up in 1996 on abandoned agricultural land. The primary aim of the experiment was to study how different secondary vegetation succession scenarios influence community development of invertebrates in

  12. Ethnoveterinary medicinal plants used by the Maale and Ari ethnic communities in southern Ethiopia

    NARCIS (Netherlands)

    Kidane, B.; Maesen, van der L.J.G.; Andel, van T.; Asfaw, Z.

    2014-01-01

    Ethnopharmacological relevance: Livestock production is an integral part of the agricultural system in Ethiopia. Medicinal plants are used and are important for rural communities for the treatment of livestock diseases. We studied and analysed the traditional medicinal plants used for the treatment

  13. Competition for light and nutrients in layered communities of aquatic plants

    NARCIS (Netherlands)

    Van Gerven, Luuk P.A.; de Klein, J.J.M; Gerla, Daan J.; Kooi, B.W.; Kuiper, Jan J.; Mooij, Wolf M.

    2015-01-01

    Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at

  14. Competition for Light and Nutrients in Layered Communities of Aquatic Plants

    NARCIS (Netherlands)

    van Gerven, L.P.A.; de Klein, J.J.M.; Gerla, D.J.; Kooi, B.W.; Kuiper, J.J.; Mooij, W.M.

    2015-01-01

    Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at

  15. Competition for light and nutrients in layered communities of aquatic plants

    NARCIS (Netherlands)

    Gerven, van Luuk P.A.; Klein, de Jeroen J.M.; Gerla, Daan J.; Kooi, Bob W.; Kuiper, Jan J.; Mooij, Wolf M.

    2015-01-01

    Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that

  16. Hierarchical spatial point process analysis for a plant community with high biodiversity

    DEFF Research Database (Denmark)

    Illian, Janine B.; Møller, Jesper; Waagepetersen, Rasmus

    2009-01-01

    A complex multivariate spatial point pattern of a plant community with high biodiversity is modelled using a hierarchical multivariate point process model. In the model, interactions between plants with different post-fire regeneration strategies are of key interest. We consider initially a maxim...

  17. Microbial Communities in Danish Wastewater Treatment Plants with Nutrient Removal

    DEFF Research Database (Denmark)

    Mielczarek, Artur Tomasz

    Activated sludge treatment plants are the most used wastewater treatment systems worldwide for biological nutrient removal from wastewater. Nevertheless, the treatment systems have been for many years operated as so called “black-box”, where specific process parameters were adjusted without...... that plants with return sludge Side-Stream Hydrolysis (SSH) instead of the normal anaerobic process tank tended to have significantly fewer unwanted GAOs in contrast to many plants with traditional mainstream anaerobic tank and thus it was proposed that this system might be an effective strategy of control...

  18. Wetland Plants of Great Salt Lake, A Guide to Identification, Communities, & Bird Habitat

    OpenAIRE

    Downard, Rebekah; Frank, Maureen; Perkins, Jennifer; Kettenring, Karin; Larese-Casanova, Mark

    2017-01-01

    Wetland Plants of Great Salt Lake: a guide to identification, communities, & bird habitat is a wetland plant identification guide, resulting from collaborative research efforts about Great Salt Lake (GSL) wetland conditions and bird habitat. Dr. Rebekah Downard collected dissertation field data from GSL wetlands during 2012–2015, the majority of which informed this work. Dr. Maureen Frank contributed her guide to GSL wetland vegetation and how to manage native plants as high-quality habitat f...

  19. THE CONCENTRATION OF PHOTOSINTHESIS PIGMENTS IN THE ANTHROPOGENIC PLANT COMMUNITIES IN TOBOLSK TOWN

    OpenAIRE

    Еlena Ivanovna Popova

    2016-01-01

    Photosynthesis means a lot in the life of a plant body. For the normal photosynthesis process it is necessary to have certain external and internal conditions. The topic of the research is the study of photosynthesis pigments in anthropogenic plant communities. The aim of our work was to study the pigment composition plants of anthropogenic phytocenoses. Methods: we have used the spectrophotometric method to define the concentration of pigments. Results: the research has shown that the concen...

  20. Contrasting the community structure of arbuscular mycorrhizal fungi from hydrocarbon-contaminated and uncontaminated soils following willow (Salix spp. L. planting.

    Directory of Open Access Journals (Sweden)

    Saad El-Din Hassan

    Full Text Available Phytoremediation is a potentially inexpensive alternative to chemical treatment of hydrocarbon-contaminated soils, but its success depends heavily on identifying factors that govern the success of root-associated microorganisms involved in hydrocarbon degradation and plant growth stimulation. Arbuscular mycorrhizal fungi (AMF form symbioses with many terrestrial plants, and are known to stimulate plant growth, although both species identity and the environment influence this relationship. Although AMF are suspected to play a role in plant adaptation to hydrocarbon contamination, their distribution in hydrocarbon-contaminated soils is not well known. In this study, we examined how AMF communities were structured within the rhizosphere of 11 introduced willow cultivars as well as unplanted controls across uncontaminated and hydrocarbon-contaminated soils at the site of a former petrochemical plant. We obtained 69 282 AMF-specific 18S rDNA sequences using 454-pyrosequencing, representing 27 OTUs. Contaminant concentration was the major influence on AMF community structure, with different AMF families dominating at each contaminant level. The most abundant operational taxonomic unit in each sample represented a large proportion of the total community, and this proportion was positively associated with increasing contamination, and seemingly, by planting as well. The most contaminated soils were dominated by three phylotypes closely related to Rhizophagus irregularis, while these OTUs represented only a small proportion of sequences in uncontaminated and moderately contaminated soils. These results suggest that in situ inoculation of AMF strains could be an important component of phytoremediation treatments, but that strains should be selected from the narrow group that is both adapted to contaminant toxicity and able to compete with indigenous AMF species.

  1. Contrasting the community structure of arbuscular mycorrhizal fungi from hydrocarbon-contaminated and uncontaminated soils following willow (Salix spp. L.) planting.

    Science.gov (United States)

    Hassan, Saad El-Din; Bell, Terrence H; Stefani, Franck O P; Denis, David; Hijri, Mohamed; St-Arnaud, Marc

    2014-01-01

    Phytoremediation is a potentially inexpensive alternative to chemical treatment of hydrocarbon-contaminated soils, but its success depends heavily on identifying factors that govern the success of root-associated microorganisms involved in hydrocarbon degradation and plant growth stimulation. Arbuscular mycorrhizal fungi (AMF) form symbioses with many terrestrial plants, and are known to stimulate plant growth, although both species identity and the environment influence this relationship. Although AMF are suspected to play a role in plant adaptation to hydrocarbon contamination, their distribution in hydrocarbon-contaminated soils is not well known. In this study, we examined how AMF communities were structured within the rhizosphere of 11 introduced willow cultivars as well as unplanted controls across uncontaminated and hydrocarbon-contaminated soils at the site of a former petrochemical plant. We obtained 69 282 AMF-specific 18S rDNA sequences using 454-pyrosequencing, representing 27 OTUs. Contaminant concentration was the major influence on AMF community structure, with different AMF families dominating at each contaminant level. The most abundant operational taxonomic unit in each sample represented a large proportion of the total community, and this proportion was positively associated with increasing contamination, and seemingly, by planting as well. The most contaminated soils were dominated by three phylotypes closely related to Rhizophagus irregularis, while these OTUs represented only a small proportion of sequences in uncontaminated and moderately contaminated soils. These results suggest that in situ inoculation of AMF strains could be an important component of phytoremediation treatments, but that strains should be selected from the narrow group that is both adapted to contaminant toxicity and able to compete with indigenous AMF species.

  2. The Root-Associated Microbial Community of the World's Highest Growing Vascular Plants.

    Science.gov (United States)

    Angel, Roey; Conrad, Ralf; Dvorsky, Miroslav; Kopecky, Martin; Kotilínek, Milan; Hiiesalu, Inga; Schweingruber, Fritz; Doležal, Jiří

    2016-08-01

    Upward migration of plants to barren subnival areas is occurring worldwide due to raising ambient temperatures and glacial recession. In summer 2012, the presence of six vascular plants, growing in a single patch, was recorded at an unprecedented elevation of 6150 m.a.s.l. close to the summit of Mount Shukule II in the Western Himalayas (Ladakh, India). Whilst showing multiple signs of stress, all plants have managed to establish stable growth and persist for several years. To learn about the role of microbes in the process of plant upward migration, we analysed the root-associated microbial community of the plants (three individuals from each) using microscopy and tagged amplicon sequencing. No mycorrhizae were found on the roots, implying they are of little importance to the establishment and early growth of the plants. However, all roots were associated with a complex bacterial community, with richness and diversity estimates similar or even higher than the surrounding bare soil. Both soil and root-associated communities were dominated by members of the orders Sphingomonadales and Sphingobacteriales, which are typical for hot desert soils, but were different from communities of temperate subnival soils and typical rhizosphere communities. Despite taxonomic similarity on the order level, the plants harboured a unique set of highly dominant operational taxonomic units which were not found in the bare soil. These bacteria have been likely transported with the dispersing seeds and became part of the root-associated community following germination. The results indicate that developing soils act not only as a source of inoculation to plant roots but also possibly as a sink for plant-associated bacteria.

  3. Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient

    Energy Technology Data Exchange (ETDEWEB)

    Notten, M.J.M. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands)]. E-mail: martje.notten@ecology.falw.vu.nl; Oosthoek, A.J.P. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands); Rozema, J. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands); Aerts, R. [Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam (Netherlands)

    2005-11-15

    We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations were 4-20 times higher than those in the reference locations. Positive relationships between the generally low leaf concentrations and the soil concentrations were found for Zn only (r {sup 2} = 0.20). Bioaccumulation of Zn, Cu and Cd was observed in the snail tissues. We found positive relationships between the snail and leaf concentrations for all metals (range r {sup 2} = 0.19-0.46). The relationships between soil and snail concentrations were also positive, except for Cu (range r {sup 2} = 0.15-0.33). These results suggest transfer of metals to C. nemoralis snails from U. dioica leaves and from the soil. Metal transfer from polluted leaves to C. nemoralis is more important than transfer from the soil. - Bioaccumulation and positive snail-leaf relationships suggest metal transfer from Urtica dioica leaves to Cepaea nemoralis snails.

  4. Heavy metal concentrations in a soil-plant-snail food chain along a terrestrial soil pollution gradient

    International Nuclear Information System (INIS)

    Notten, M.J.M.; Oosthoek, A.J.P.; Rozema, J.; Aerts, R.

    2005-01-01

    We investigated concentrations of Zn, Cu, Cd and Pb in the compartments of a soil-plant (Urtica dioica)-snail (Cepaea nemoralis) food chain in four polluted locations in the Biesbosch floodplains, the Netherlands, and two reference locations. Total soil metal concentrations in the polluted locations were 4-20 times higher than those in the reference locations. Positive relationships between the generally low leaf concentrations and the soil concentrations were found for Zn only (r 2 = 0.20). Bioaccumulation of Zn, Cu and Cd was observed in the snail tissues. We found positive relationships between the snail and leaf concentrations for all metals (range r 2 = 0.19-0.46). The relationships between soil and snail concentrations were also positive, except for Cu (range r 2 = 0.15-0.33). These results suggest transfer of metals to C. nemoralis snails from U. dioica leaves and from the soil. Metal transfer from polluted leaves to C. nemoralis is more important than transfer from the soil. - Bioaccumulation and positive snail-leaf relationships suggest metal transfer from Urtica dioica leaves to Cepaea nemoralis snails

  5. Insect herbivory and plant adaptation in an early successional community.

    Science.gov (United States)

    Agrawal, Anurag A; Hastings, Amy P; Fines, Daniel M; Bogdanowicz, Steve; Huber, Meret

    2018-05-01

    To address the role of insect herbivores in adaptation of plant populations and the persistence of selection through succession, we manipulated herbivory in a long-term field experiment. We suppressed insects in half of 16 plots over nine years and examined the genotypic structure and chemical defense of common dandelion (Taraxacum officinale), a naturally colonizing perennial apomictic plant. Insect suppression doubled dandelion abundance in the first few years, but had negligible effects thereafter. Using microsatellite DNA markers, we genotyped >2500 plants and demonstrate that insect suppression altered the genotypic composition of plots in both sampling years. Phenotypic and genotypic estimates of defensive terpenes and phenolics from the field plots allowed us to infer phenotypic plasticity and the response of dandelion populations to insect-mediated natural selection. The effects of insect suppression on plant chemistry were, indeed, driven both by plasticity and plant genotypic identity. In particular, di-phenolic inositol esters were more abundant in plots exposed to herbivory (due to the genotypic composition of the plots) and were also induced in response to herbivory. This field experiment thus demonstrates evolutionary sorting of plant genotypes in response to insect herbivores that was in same direction as the plastic defensive response within genotypes. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  6. Experimental restoration of a fen plant community after peat mining

    Energy Technology Data Exchange (ETDEWEB)

    Cobbaert, D.; Rochefort, L.; Price, J.S. [Univ. Laval, Sainte-Foy (Canada). Dept. de Phytologie

    2004-11-01

    Methods: The effectiveness of introducing fen plants with the application of donor diaspore material was tested. The donor diaspore material, containing seeds, rhizomes, moss fragments, and other plant propagules, was collected from two different types of natural fens. We tested whether the application of straw mulch would increase fen species cover and biodiversity compared to control plots without straw mulch. Terrace levels of different peat depths (15 cm, 40 cm, and 56 cm) were created to test the effects of different environmental site conditions on the success of re-vegetation. Results: Applying donor seed bank from natural fens was found to significantly increase fen plant cover and richness after the two growing seasons. Straw mulch proved to significantly increase fen plant richness. The intermediate terrace level (40 cm) had the highest fen plant establishment. Compared to reference sites, the low terrace level (15 cm) was richer in base cations, whereas the high terrace level (56 cm) was much drier. Conclusions: The application of donor diaspore material was demonstrated as an effective technique for establishing vascular fen plants. Further rewetting measures are considered necessary at the restoration site to create a fen ecosystem rather than simply restoring some fen species (Location: Riviere-du-Loup peatland, southern Quebec, Canada at 100 m a.s.l.)

  7. Indigenous knowledge of medicinal plants used by Saperas community of Khetawas, Jhajjar District, Haryana, India

    Directory of Open Access Journals (Sweden)

    Kumar Sunil

    2010-01-01

    Full Text Available Abstract Background Plants have traditionally been used as a source of medicine in India by indigenous people of different ethnic groups inhabiting various terrains for the control of various ailments afflicting human and their domestic animals. The indigenous community of snake charmers belongs to the 'Nath' community in India have played important role of healers in treating snake bite victims. Snake charmers also sell herbal remedies for common ailments. In the present paper an attempt has been made to document on ethno botanical survey and traditional medicines used by snake charmers of village Khetawas located in district Jhajjar of Haryana, India as the little work has been made in the past to document the knowledge from this community. Methods Ethno botanical data and traditional uses of plants information was obtained by semi structured oral interviews from experienced rural folk, traditional herbal medicine practitioners of the 'Nath' community. A total of 42 selected inhabitants were interviewed, 41 were male and only one woman. The age of the healers was between 25 years and 75 years. The plant specimens were identified according to different references concerning the medicinal plants of Haryana and adjoining areas and further confirmation from Forest Research Institute, Dehradun. Results The present study revealed that the people of the snake charmer community used 57 medicinal plants species that belonged to 51 genera and 35 families for the treatment of various diseases. The study has brought to light that the main diseases treated by this community was snakebite in which 19 different types of medicinal plants belongs to 13 families were used. Significantly higher number of medicinal plants was claimed by men as compared to women. The highest numbers of medicinal plants for traditional uses utilized by this community were belonging to family Fabaceae. Conclusion This community carries a vast knowledge of medicinal plants but as

  8. Predictive occurrence models for coastal wetland plant communities: delineating hydrologic response surfaces with multinomial logistic regression

    Science.gov (United States)

    Snedden, Gregg A.; Steyer, Gregory D.

    2013-01-01

    Understanding plant community zonation along estuarine stress gradients is critical for effective conservation and restoration of coastal wetland ecosystems. We related the presence of plant community types to estuarine hydrology at 173 sites across coastal Louisiana. Percent relative cover by species was assessed at each site near the end of the growing season in 2008, and hourly water level and salinity were recorded at each site Oct 2007–Sep 2008. Nine plant community types were delineated with k-means clustering, and indicator species were identified for each of the community types with indicator species analysis. An inverse relation between salinity and species diversity was observed. Canonical correspondence analysis (CCA) effectively segregated the sites across ordination space by community type, and indicated that salinity and tidal amplitude were both important drivers of vegetation composition. Multinomial logistic regression (MLR) and Akaike's Information Criterion (AIC) were used to predict the probability of occurrence of the nine vegetation communities as a function of salinity and tidal amplitude, and probability surfaces obtained from the MLR model corroborated the CCA results. The weighted kappa statistic, calculated from the confusion matrix of predicted versus actual community types, was 0.7 and indicated good agreement between observed community types and model predictions. Our results suggest that models based on a few key hydrologic variables can be valuable tools for predicting vegetation community development when restoring and managing coastal wetlands.

  9. Predictive occurrence models for coastal wetland plant communities: Delineating hydrologic response surfaces with multinomial logistic regression

    Science.gov (United States)

    Snedden, Gregg A.; Steyer, Gregory D.

    2013-02-01

    Understanding plant community zonation along estuarine stress gradients is critical for effective conservation and restoration of coastal wetland ecosystems. We related the presence of plant community types to estuarine hydrology at 173 sites across coastal Louisiana. Percent relative cover by species was assessed at each site near the end of the growing season in 2008, and hourly water level and salinity were recorded at each site Oct 2007-Sep 2008. Nine plant community types were delineated with k-means clustering, and indicator species were identified for each of the community types with indicator species analysis. An inverse relation between salinity and species diversity was observed. Canonical correspondence analysis (CCA) effectively segregated the sites across ordination space by community type, and indicated that salinity and tidal amplitude were both important drivers of vegetation composition. Multinomial logistic regression (MLR) and Akaike's Information Criterion (AIC) were used to predict the probability of occurrence of the nine vegetation communities as a function of salinity and tidal amplitude, and probability surfaces obtained from the MLR model corroborated the CCA results. The weighted kappa statistic, calculated from the confusion matrix of predicted versus actual community types, was 0.7 and indicated good agreement between observed community types and model predictions. Our results suggest that models based on a few key hydrologic variables can be valuable tools for predicting vegetation community development when restoring and managing coastal wetlands.

  10. Invasion of Opuntia humifusa and O. phaeacantha (Cactaceae into plant communities of the Karadag Nature Reserve

    Directory of Open Access Journals (Sweden)

    Valentina V. Fateryga

    2017-11-01

    Full Text Available The results of a study of Opuntia humifusa and O. phaeacantha naturalised in the Karadag Nature Reserve (southeastern part of the Crimean Peninsula are presented. There, the largest coenopopulations of Opuntia plants are confined to the «biostation» territory (bordering with the park, administrative buildings and housing estate. Twelve localities were described in the Karadag Reserve. These differ by phytocoenotic characteristics, area and floristic composition. Seven localities include only O. humifusa plants; four ones include only O. phaeacantha individuals; and both the species are present on the twelfth locality. The total number of individuals of each species and ontogenetic structure of the population were studied in each locality. The total number of O. humifusa individuals in the Karadag Reserve is more than 600 plants within the «biostation» territory, while the total number of O. phaeacantha plants is about 400 individuals. Studying of the plant communities has been carried out according to the Braun-Blanquet method. Opuntia plants form derivate communities within degraded steppes, phryganoid-steppes, and semi-desert badland phytocoenoses almost at all studied localities. A significant number of synanthropic species (including alien plants was found within these communities. Opuntia plants are able to self-reproduce predominantly vegetatively. Self-seeding reproduction occurs less frequently. Both species can be considered as invasive plants because they have a high adaptive capacity.

  11. Structure and composition of oligohaline marsh plant communities exposed to salinity pulses

    Science.gov (United States)

    Howard, R.J.; Mendelssohn, I.A.

    2000-01-01

    The response of two oligohaline marsh macrophyte communities to pulses of increased salinity was studied over a single growing season in a greenhouse experiment. The plant communities were allowed a recovery period in freshwater following the pulse events. The experimental treatments included: (1) salinity influx rate (rate of salinity increase from 0 to 12 gl-1); (2) duration of exposure to elevated salinity; and (3) water depth. The communities both included Sagittaria lancifolia L.; the codominant species were Eleocharis palustris (L.) Roemer and J.A. Schultes in community 1 and Schoenoplectus americanus (Pers.) Volk. ex Schinz and R. Keller in community 2. Effects of the treatments on sediment chemical characteristics (salinity, pH, redox potential, and sulfide and ammonium concentrations) and plant community attributes (aboveground and belowground biomass, stem density, leaf tissue nutrients, and species richness) were examined. The treatment effects often interacted to influence sediment and plant communities characteristics following recovery in fresh water. Salinity influx rate per se, however, had little effect on the abiotic or biotic response variables; significant influx effects were found when the 0 gl-1 (zero influx) treatment was compared to the 12 gl-1 treatments, regardless of the rate salinity was raised. A salinity level of 12 gl-1 had negative effects on plant community structure and composition; these effects were usually associated with 3 months of salinity exposure. Water depth often interacted with exposure duration, but increased water depth did independently decrease the values of some community response measures. Community 1 was affected more than community 2 in the most extreme salinity treatment (3 months exposure/15-cm water depth). Although species richness in both communities was reduced, structural changes were more dramatic in community 1. Biomass and stem density were reduced in community 1 overall and in both dominant species

  12. Plants of the fynbos biome harbour host species-specific bacterial communities.

    Science.gov (United States)

    Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

    2016-08-01

    The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Differences in the availabilities of cesium-134,137 and ruthenium-106 from a Chernobyl-contaminated soil to a water plant, duckweed, and to the terrestrial plants, bean and lettuce

    International Nuclear Information System (INIS)

    Polar, E.; Bayuelgen, N.

    1991-01-01

    The aqueous solubilities of some radionuclides present in a Chernobyl-contaminated soil and their subsequent availabilities to an aquatic plant, duckweed (Lemnaceae), were compared to those obtained for bean (Phaseolus vulgaris) and lettuce (Lactuca sativa). During this investigation carried out in laboratory conditions, it was observed that, although around 0.06% of 134 Cs or 137 Cs present in the soil was detected in the aqueous phase, duckweed concentrated 1000-5500 times this amount, depending on plant species. By contrast, 106 Ru in the soil was leached more effectively into solution than was cesium but its accumulation into duckweed was less. The effects on the availabilities of ruthenium and cesium of depletion of soil organic matter and of amendment of the aqueous phase with nutrients were also investigated. The transfer factors of 134,137 Cs into bean and lettuce cultivated in the same soil were 0.02 and 0.06, respectively, while that for 106 Ru was around 0.2. The difference between aquatic and terrestrial plants in cycling radionuclides is briefly discussed. (author)

  14. Differences in the availabilities of cesium-134,137 and ruthenium-106 from a Chernobyl-contaminated soil to a water plant, duckweed, and to the terrestrial plants, bean and lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Polar, E.; Bayuelgen, N. (Cekmece Nuclear Research and Training Center, Istanbul (Turkey))

    1991-01-01

    The aqueous solubilities of some radionuclides present in a Chernobyl-contaminated soil and their subsequent availabilities to an aquatic plant, duckweed (Lemnaceae), were compared to levels found in bean (Phaseolus vulgaris) and lettuce (Lactuca sativa). During this investigation carried out in laboratory conditions, it was observed that, although around 0.06% of {sup 134}Cs or {sup 137}Cs present in the soil was detected in the aqueous phase, duckweed concentrated 1000-5500 times this amount, depending on plant species. By contrast, {sup 106}Ru in the soil was leached more effectively into solution than was cesium but its accumulation into duckweed was less. The effects on the availabilities of ruthenium and cesium of depletion of soil organic matter and of amendment of the aqueous phase with nutrients were also investigated. The transfer factors of {sup 134,137}Cs into bean and lettuce cultivated in the same soil were 0.02 and 0.06, respectively, while that for {sup 106}Ru was around 0.2. The difference between aquatic and terrestrial plants in cycling radionuclides is briefly discussed. (author).

  15. Lags in the response of mountain plant communities to climate change

    DEFF Research Database (Denmark)

    Alexander, Jake M; Chalmandrier, Loïc; Lenoir, Jonathan

    2018-01-01

    Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind...... plant species' spread along elevational gradients, "establishment lags" following their arrival in recipient communities, and "extinction lags" of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic...... turnover in future communities might lag behind simple expectations based on species' range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our...

  16. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion.

    Science.gov (United States)

    Connolly, B M; Pearson, D E; Mack, R N

    2014-07-01

    Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small

  17. Advances in modeling trait-based plant community assembly.

    Science.gov (United States)

    Laughlin, Daniel C; Laughlin, David E

    2013-10-01

    In this review, we examine two new trait-based models of community assembly that predict the relative abundance of species from a regional species pool. The models use fundamentally different mathematical approaches and the predictions can differ considerably. Maxent obtains the most even probability distribution subject to community-weighted mean trait constraints. Traitspace predicts low probabilities for any species whose trait distribution does not pass through the environmental filter. Neither model maximizes functional diversity because of the emphasis on environmental filtering over limiting similarity. Traitspace can test for the effects of limiting similarity by explicitly incorporating intraspecific trait variation. The range of solutions in both models could be used to define the range of natural variability of community composition in restoration projects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Stubble field plant communities of the Mazowiecki Landscape Park

    Directory of Open Access Journals (Sweden)

    Teresa Skrajna

    2012-12-01

    Full Text Available The characteristics of communities found in unploughed stubble fields of the Mazowiecki Landscape Park and its agricultural buffer zone are presented in the paper. The association Echinochloo-Setarietum divided into a typical variant, the variant with Galinsoga parviflora, and the variant with Bidens tripartite, was the most frequently noted and floristically differentiated association. Patches of Digitarietum ischaemi were also frequently observed in stubble fields on the poorest habitats. Rarely, on fertile soils, small patches of floristically rich communities with Veronica agrestis were recorded. Periodically, excessively wet habitats were seldom occupied by the speciesrichest phytocoenoses of Centunculo-Anthoceretum punctati. Single patches of the community with Setaria pumila, the form with Aphanes arvensis, were observed only in the south-eastern part of the Park.

  19. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  20. Effects of water table position and plant functional group on plant community, aboveground production, and peat properties in a peatland mesocosm experiment (PEATcosm)

    Science.gov (United States)

    Lynette R. Potvin; Evan S. Kane; Rodney A. Chimner; Randall K. Kolka; Erik A. Lilleskov

    2015-01-01

    Aims Our objective was to assess the impacts of water table position and plant functional type on peat structure, plant community composition and aboveground plant production. Methods We initiated a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: sedge, Ericaceae,...

  1. Community Visions for the Paducah Gaseous Diffusion Plant Site

    Energy Technology Data Exchange (ETDEWEB)

    Ormsbee, Lindell e [Civil Engineering, Univ. of KY; Kipp, James A [Univ. of KY, Kentucky water research Institute

    2011-09-01

    This report focuses on assessing community preferences for the future use of the PGDP site, given the site's pending closure by US DOE. The project approach fostered interaction and engagement with the public based on lessons learned at other complex DOE environmental cleanup sites and upon the integration of a number of principles and approaches to public engagement from the Project Team's local, state, regional and international public engagement experience. The results of the study provide the community with a record of the diversity of values and preferences related to the environmental cleanup and future use of the site.

  2. Litter drives ecosystem and plant community changes in cattail invasion.

    Science.gov (United States)

    Farrer, Emily C; Goldberg, Deborah E

    2009-03-01

    Invaded systems are commonly associated with a change in ecosystem processes and a decline in native species diversity; however, many different causal pathways linking invasion, ecosystem change, and native species decline could produce this pattern. The initial driver of environmental change may be anthropogenic, or it may be the invader itself; and the mechanism behind native species decline may be the human-induced environmental change, competition from the invader, or invader-induced environmental change (non-trophic effects). We examined applicability of each of these alternate pathways in Great Lakes coastal marshes invaded by hybrid cattail (Typha x glauca). In a survey including transects in three marshes, we found that T. x glauca was associated with locally high soil nutrients, low light, and large amounts of litter, and that native diversity was highest in areas of shallow litter depth. We tested whether live T. x glauca plants or their litter induced changes in the environment and in diversity with a live plant and litter transplant experiment. After one year, Typha litter increased soil NH4+ and N mineralization twofold, lowered light levels, and decreased the abundance and diversity of native plants, while live Typha plants had no effect on the environment or on native plants. This suggests that T. x glauca, through its litter production, can cause the changes in ecosystem processes that we commonly attribute to anthropogenic nutrient loading and that T. x glauca does not displace native species through competition for resources, but rather affects them non-trophically through its litter. Moreover, because T. x glauca plants were taller when grown with their own litter, we suggest that this invader may produce positive feedbacks and change the environment in ways that benefit itself and may promote its own invasion.

  3. Simulation of plant communities with a cellular automaton

    Energy Technology Data Exchange (ETDEWEB)

    Gassmann, F [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    With a modelling approach based on cellular automata, five observed types of plant development can be simulated. In addition, the proposed model shows a strong tendency towards the formation of patches and a high degree of dynamical and structural instability leading to limits of predictability for the asymptotic solution chosen by the system among several possible metastable patterns (multistability). Further, external fluctuations can be shown to have advantages for certain plant types. The presented model unifies the fundamental dichotomy in vegetation dynamics between determinism (understood as predictability) and disorder (chance effects) by showing the outcome of both classical theories as special cases. (author) 2 figs., 4 refs.

  4. Life form succession in plant communities on colliery waste tips

    Energy Technology Data Exchange (ETDEWEB)

    Down, C G

    1973-01-01

    Five disused colliery waste tips in the Somerset Coalfield, 12, 15, 21, 55 and 98 years old, respectively, were examined to determine the life forms of the naturally-occurring vascular plant species. Hemicryptophytes comprised between 68 and 79% of the number of species on each tip. Rosette hemicryptophytes comprised 31.8% of the species on the 12-year tip, declining to 11.8% on the 98-year tip. It is suggested that artificial planting of rosette hemicryptophytes may be beneficial in reclamation schemes. 3 tables.

  5. Biodiversity, Community and Trophic Structure of the Suprabenthos of the Gulf of Cádiz-Guadalquivir Estuary Coupled System: Linking Pelagic-Benthic and Terrestrial-Marine Ecosystems.

    Science.gov (United States)

    Vilas, C.

    2016-02-01

    Suprabenthos biodiversity and species densities on both offshore and coastal systems are largely unknown. Main components like mysids, euphasiids or amphipods are omnivorous and constitute a major dietary component for many benthic and pelagic fishes, mammals, cephalopods and decapods. Despite their relevant ecological role linking pelagic-benthic food webs, suprabenthos have been chronically undersampled and their components underrepresented and underestimated in food web models. Many pelagic and demersal species of high commercial and ecological interest at the Gulf of Cádiz (GoC) feed at a bottom scattering layer identified from 0 to 200 m depth and up to 50 km from coast, related to the Guadalquivir Estuary (GE) influence coastal area, and present life history cycles based on a sequential use of habitats from GoC to GE nursery area, may be adapted to match the horizontal migrations of key suprabenthos prey species. In order to understand the ecological mechanisms through which the GE-GoC coupled ecosystem would influence the recruitment of these fishery resources, the suprabenthos was sampled by suprabenthic sldege (200 μm) from the shallow estuary to 75 m depth during June, August and November of 2013. We identified up to 300 species (H index 0.4-2-9 and Beta diversity 0.55), being copepods, molluscs, cumacea, cladocera, poliquets, decapods, mysids and amphipods the most important groups by biomass (mg/m3), finding densities up to 32.9 mg/m3 for copepods, 6 for mysids and up to 100 mg/m3 for decapods. Multivariate analysis determines depth as the most important variable explaining community structure, decreasing biodiversity with depth, while for sites at depths species show seasonal horizontal migrations between GoC and GE, connecting terrestrial and marine ecosystems.

  6. [Soil catalase activity of main plant communities in Leymus chinensis grassland in northeast China].

    Science.gov (United States)

    Lu, Ping; Guo, Jixun; Zhu, Li

    2002-06-01

    The seasonal dynamics of soil catalase activity of three different plants communities in Leymus chinensis grassland in northeast China were in a parabolas shape. The seasonal variation of Chloris virgata community was greater than those of Leymus chinensis community and Puccinellia tenuiflora community, and "seed effect" might be the main reason. The correlation between the activity of soil catalase in different soil layers and environmental factors were analyzed. The results showed that the activity of soil catalase was decreased gradually with depth of soil layer. The activity of soil catalase was closely correlated with rainfall and air temperature, and it was affected by soil temperature, soil moisture, and their interactions. The correlation between the activity and aboveground vegetation was very significant, and the growing condition of plant communities could be reflected by the activity of soil catalase.

  7. Terrestrial ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The main effort of the Terrestrial Ecology Division has been redirected to a comprehensive study of the Espiritu Santo Drainage Basin located in northeastern Puerto Rico. The general objective are to provide baseline ecological data for future environmental assessment studies at the local and regional levels, and to provide through an ecosystem approach data for the development of management alternatives for the wise utilization of energy, water, and land resources. The interrelationships among climate, vegetation, soils, and man, and their combined influence upon the hydrologic cycle will be described and evaluated. Environmental management involves planning and decision making, and both require an adequate data base. At present, little is known about the interworkings of a complete, integrated system such as a drainage basin. A literature survey of the main research areas confirmed that, although many individual ecologically oriented studies have been carried out in a tropical environment, few if any provide the data base required for environmental management. In view of rapidly changing socio-economic conditions and natural resources limitations, management urgently requires data from these systems: physical (climatological), biological, and cultural. This integrated drainage basin study has been designed to provide such data. The scope of this program covers the hydrologic cycle as it is affected by the interactions of the physical, biological, and cultural systems

  8. [Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

    Science.gov (United States)

    Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

    2017-12-01

    The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

  9. Dispersal and life span spectra in plant communities : a key to safe site dynamics, species coexistence and conservation

    NARCIS (Netherlands)

    Strykstra, RJ; Bekker, RM; Van Andel, J

    Dispersal and life span of individual plant species within five plant communities were assessed to obtain a characterization of these communities in this respect. Such a characterization is important in the context of restoration and maintenance. The most frequent species of five communities were

  10. Interior West community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    Kelaine E. Vargas; Gregory E. McPherson; James R. Simpson; Paula J. Peper; Shelley L. Gardner; Qingfu. Xiao

    2007-01-01

    Even as they increase the beauty of our surroundings, trees provide us with a great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest...

  11. Central Florida community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    Paula J. Peper; E. Gregory McPherson; James R. Simpson; Shannon N. Albers; Qingfu Xiao

    2010-01-01

    Trees make our cities more attractive and provide many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest control, liability, cleanup, and removal...

  12. Desert Southwest Community Tree Guide: Benefits, Costs and Strategic Planting

    Science.gov (United States)

    Greg McPherson; J.R. Simpson; P.J. Peper; S.E. Maco; Q. Xiao; E. Mulrean

    2004-01-01

    This report quantifies benefits and costs for typical large-, medium-, small-stature, deciduous trees (Fraxinus uhdei, Prosopis chilensis, Acacia farnesiana), as well as a conifer (Pinus halapensis). The analysis assumed that trees were planted in a residential yard site or a public (street/park) site, a 40-year time frame, and...

  13. Lower Midwest community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    Paula J. Peper; E. Gregory McPherson; James R. Simpson; Kelaine E. Vargas; Qingfu Xiao

    2009-01-01

    Even as they increase the beauty of our surroundings, trees provide us with a great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest...

  14. Tropical community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    Kelaine E. Vargas; Gregory E. McPherson; James R. Simpson; Paula J. Peper; Shelley L. Gardner; Qingfu Xiao

    2008-01-01

    Even as they increase the beauty of our surroundings, trees provide us with a great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest...

  15. Midwest community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    E. Gregory McPherson; James R. Simpson; Paula J. Peper; Scott E. Maco; Shelley L. Gardner; Shauna K. Cozad; Qingfu Xiao

    2006-01-01

    This report quantifies benefits and costs for typical small, medium, and large deciduous (losing their leaves every autumn) trees: crabapple, red oak, and hackberry (see "Common and Scientific Names" section). The analysis assumed that trees were planted in a residential yard or public site (streetside or park) with a 60 percent survival rate over a 40-year...

  16. Northeast community tree guide: benefits, costs, and strategic planting

    Science.gov (United States)

    E. Gregory McPherson; James R. Simpson; Paula J. Peper; Shelley L. Gardner; Kelaine E. Vargas; Qingfu Xiao

    2007-01-01

    Trees make our cities more attractive and provide many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest control, liability, cleanup, and removal...

  17. Ecological surveys of certain plant communities around urban areas ...

    African Journals Online (AJOL)

    It was also observed that certain edaphic and human activity, discharge of pollutants with out any pretreatment was found responsible for variation in the nature, structure and composition of vegetation. The plant growth and their continuity was in danger in many disturb areas, especially in some coastal areas where salinity ...

  18. Effects of the herbicide metsulfuron-methyl on a plant community, including seed germination success in the F1 generation

    NARCIS (Netherlands)

    Nelemans, J.B.; Wijngaarden, van René P.A.; Roessink, Ivo; Arts, Gertie H.P.

    2017-01-01

    A field trial was set up to simulate a field margin environment to analyze sub-lethal effects of the herbicide metsulfuron-methyl on several endpoints of non-target terrestrial plants (NTTPs). Both vegetative and reproductive endpoints were evaluated. The experiment was conducted in an

  19. The D3-D5 region of large subunit ribosomal DNA provides good resolution of German limnic and terrestrial nematode communities

    NARCIS (Netherlands)

    Schenk, Janina; Hohberg, Karin; Helder, Hans; Ristau, Kai; Traunspurger, Walter

    2017-01-01

    Reliable and well-developed DNA barcode databases are indispensable for the identification of microscopic life. However, effectiveness of molecular barcoding in identifying terrestrial specimens, and nematodes in particular, has received little attention. In this study, ca 600 ribosomal large

  20. Climate change drives a shift in peatland ecosystem plant community: implications for ecosystem function and stability.

    Science.gov (United States)

    Dieleman, Catherine M; Branfireun, Brian A; McLaughlin, James W; Lindo, Zoë

    2015-01-01

    The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO2 ), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 °C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 °C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 °C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO2 had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid-dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens. © 2014 John Wiley & Sons Ltd.

  1. Coal mining activities change plant community structure due to air pollution and soil degradation.

    Science.gov (United States)

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  2. Changes in soil bacterial communities induced by the invasive plant Pennisetum setaceum in a semiarid environment

    Science.gov (United States)

    Rodriguez-Caballero, Gema; Caravaca, Fuensanta; del Mar Alguacil, María; Fernández-López, Manuel; José Fernández-González, Antonio; García-Orenes, Fuensanta; Roldán, Antonio

    2016-04-01

    Invasive alien species are considered as a global threat being among the main causes of biodiversity loss. Plant invasions have been extensively studied from different disciplines with the purpose of identifying predictor traits of invasiveness and finding solutions. However, less is known about the implication of the rhizosphere microbiota in these processes, even when it is well known the importance of the interaction between plant rhizosphere and microbial communities. The objective of this study was to determine whether native and invasive plants support different bacterial communities in their rhizospheres and whether there are bacterial indicator species that might be contributing to the invasion process of these ecosystems. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum, an aggressive invasive Poaceae and soil bacterial communities were amplified and 454-pyrosequenced. Changes in the composition and structure of the bacterial communities, owing to the invasive status of the plant, were detected when the richness and alpha-diversity estimators were calculated as well as when we analyzed the PCoA axes scores. The Indicator Species Analysis results showed a higher number of indicators for invaded communities at all studied taxonomic levels. In conclusion, the effect of the invasiveness and its interaction with the soil location has promoted shifts in the rhizosphere bacterial communities which might be facilitating the invader success in these ecosystems.

  3. Wastewater treatment plant effluent introduces recoverable shifts in microbial community composition in urban streams

    Science.gov (United States)

    Ledford, S. H.; Price, J. R.; Ryan, M. O.; Toran, L.; Sales, C. M.

    2017-12-01

    New technologies are allowing for intense scrutiny of the impact of land use on microbial communities in stream networks. We used a combination of analytical chemistry, real-time polymerase chain reaction (qPCR) and targeted amplicon sequencing for a preliminary study on the impact of wastewater treatment plant effluent discharge on urban streams. Samples were collected on two dates above and below treatment plants on the Wissahickon Creek, and its tributary, Sandy Run, in Montgomery County, PA, USA. As expected, effluent was observed to be a significant source of nutrients and human and non-specific fecal associated taxa. There was an observed increase in the alpha diversity at locations immediately below effluent outflows, which contributed many taxa involved in wastewater treatment processes and nutrient cycling to the stream's microbial community. Unexpectedly, modeling of microbial community shifts along the stream was not controlled by concentrations of measured nutrients. Furthermore, partial recovery, in the form of decreasing abundances of bacteria and nutrients associated with wastewater treatment plant processes, nutrient cycling bacteria, and taxa associated with fecal and sewage sources, was observed between effluent sources. Antecedent moisture conditions impacted overall microbial community diversity, with higher diversity occurring after rainfall. These findings hint at resilience in stream microbial communities to recover from wastewater treatment plant effluent and are vital to understanding the impacts of urbanization on microbial stream communities.

  4. Fungal Communities in Rhizosphere Soil under Conservation Tillage Shift in Response to Plant Growth

    Directory of Open Access Journals (Sweden)

    Ziting Wang

    2017-07-01

    Full Text Available Conservation tillage is an extensively used agricultural practice in northern China that alters soil texture and nutrient conditions, causing changes in the soil microbial community. However, how conservation tillage affects rhizosphere and bulk soil fungal communities during plant growth remains unclear. The present study investigated the effect of long-term (6 years conservation (chisel plow, zero and conventional (plow tillage during wheat growth on the rhizosphere fungal community, using high-throughput sequencing of the internal transcribed spacer (ITS gene and quantitative PCR. During tillering, fungal alpha diversity in both rhizosphere and bulk soil were significantly higher under zero tillage compared to other methods. Although tillage had no significant effect during the flowering stage, fungal alpha diversity at this stage was significantly different between rhizosphere and bulk soils, with bulk soil presenting the highest diversity. This was also reflected in the phylogenetic structure of the communities, as rhizosphere soil communities underwent a greater shift from tillering to flowering compared to bulk soil communities. In general, less variation in community structure was observed under zero tillage compared to plow and chisel plow treatments. Changes in the relative abundance of the fungal orders Capnodiales, Pleosporales, and Xylariales contributed the highest to the dissimilarities observed. Structural equation models revealed that the soil fungal communities under the three tillage regimes were likely influenced by the changes in soil properties associated with plant growth. This study suggested that: (1 differences in nutrient resources between rhizosphere and bulk soils can select for different types of fungi thereby increasing community variation during plant growth; (2 tillage can alter fungal communities' variability, with zero tillage promoting more stable communities. This work suggests that long-term changes in

  5. Planting Seeds to Grow Healthy Children: Strategic Community Partnerships.

    Science.gov (United States)

    Alicea-Planas, Jessica; Sullivan, Kelly; Tran, Hang; Cruz, Anna

    2018-02-01

    More than one third of U.S adults are considered obese, and childhood obesity has more than doubled in the past 30 years. Food security can influence obesity, in particular, within inner cities where access to healthy food is often limited. The use of a mobile food truck program (with refrigeration) was implemented in two large inner cities in Connecticut as part of an initiative aimed at helping low-income families with young children gain access to healthy food and nutrition education. Collaborating with community child care centers was used. The experiences of the families who participated in the program were assessed via focus groups. Main ideas derived from the focus groups were participant satisfaction with money saving suggestions, ideas for how to make healthier choices, and excitement about opportunities to receive foods that they would not normally buy. This innovative mobile food truck program demonstrated the value of strategic community partnerships to influence health.

  6. The Upper Mississippi River floodscape: spatial patterns of flood inundation and associated plant community distributions

    Science.gov (United States)

    DeJager, Nathan R.; Rohweder, Jason J.; Yin, Yao; Hoy, Erin E.

    2016-01-01

    Questions How is the distribution of different plant communities associated with patterns of flood inundation across a large floodplain landscape? Location Thirty-eight thousand nine hundred and seventy hectare of floodplain, spanning 320 km of the Upper Mississippi River (UMR). Methods High-resolution elevation data (Lidar) and 30 yr of daily river stage data were integrated to produce a ‘floodscape’ map of growing season flood inundation duration. The distributions of 16 different remotely sensed plant communities were quantified along the gradient of flood duration. Results Models fitted to the cumulative frequency of occurrence of different vegetation types as a function of flood duration showed that most types exist along a continuum of flood-related occurrence. The diversity of community types was greatest at high elevations (0–10 d of flooding), where both upland and lowland community types were found, as well as at very low elevations (70–180 d of flooding), where a variety of lowland herbaceous communities were found. Intermediate elevations (20–60 d of flooding) tended to be dominated by floodplain forest and had the lowest diversity of community types. Conclusions Although variation in flood inundation is often considered to be the main driver of spatial patterns in floodplain plant communities, few studies have quantified flood–vegetation relationships at broad scales. Our results can be used to identify targets for restoration of historical hydrological regimes or better anticipate hydro-ecological effects of climate change at broad scales.

  7. Tracking fungal community responses to maize plants by DNA- and RNA-based pyrosequencing.

    Directory of Open Access Journals (Sweden)

    Eiko E Kuramae

    Full Text Available We assessed soil fungal diversity and community structure at two sampling times (t1 = 47 days and t2 = 104 days of plant age in pots associated with four maize cultivars, including two genetically modified (GM cultivars by high-throughput pyrosequencing of the 18S rRNA gene using DNA and RNA templates. We detected no significant differences in soil fungal diversity and community structure associated with different plant cultivars. However, DNA-based analyses yielded lower fungal OTU richness as compared to RNA-based analyses. Clear differences in fungal community structure were also observed in relation to sampling time and the nucleic acid pool targeted (DNA versus RNA. The most abundant soil fungi, as recovered by DNA-based methods, did not necessary represent the most "active" fungi (as recovered via RNA. Interestingly, RNA-derived community compositions at t1 were highly similar to DNA-derived communities at t2, based on presence/absence measures of OTUs. We recovered large proportions of fungal sequences belonging to arbuscular mycorrhizal fungi and Basidiomycota, especially at the RNA level, suggesting that these important and potentially beneficial fungi are not affected by the plant cultivars nor by GM traits (Bt toxin production. Our results suggest that even though DNA- and RNA-derived soil fungal communities can be very different at a given time, RNA composition may have a predictive power of fungal community development through time.

  8. [Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.

    Science.gov (United States)

    Zhu, Duo Ju; Wen, Zhong Ming; Zhang, Jing; Tao, Yu; Zeng, Hong Wen; Tang, Yang

    2018-02-01

    To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FR ic , FE ve , FD iv , FD is , Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.

  9. Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

    Czech Academy of Sciences Publication Activity Database

    Krüger, Claudia; Kohout, Petr; Janoušková, Martina; Püschel, David; Frouz, J.; Rydlová, Jana

    2017-01-01

    Roč. 8, APR 20 (2017), s. 1-16, č. článku 719. ISSN 1664-302X R&D Projects: GA ČR GA13-10377S; GA ČR GA15-05466S Institutional support: RVO:67985939 Keywords : biodiversity * community ecology * fungal and plant succession Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.076, year: 2016

  10. Ignored fungal community in activated sludge wastewater treatment plants: diversity and altitudinal characteristics.

    Science.gov (United States)

    Niu, Lihua; Li, Yi; Xu, Lingling; Wang, Peifang; Zhang, Wenlong; Wang, Chao; Cai, Wei; Wang, Linqiong

    2017-02-01

    Fungi are important contributors to the various functions of activated sludge wastewater treatment plants (WWTPs); however, the diversity and geographic characteristics of fungal populations have remained vastly unexplored. Here, quantitative polymerase chain reaction and 454 pyrosequencing were combined to investigate the abundance and diversity of the activated sludge fungal communities from 18 full-scale municipal WWTPs in China. Phylogenetic taxonomy revealed that the members of the fungal communities were assigned to 7 phyla and 195 genera. Ascomycota and Basidiomycota were the most abundant phyla, dominated by Pluteus, Wickerhamiella, and Penicillium. Twenty-three fungal genera, accounting for 50.1 % of the total reads, were shared by 18 WWTPs and constituted a core fungal community. The fungal communities presented similar community diversity but different community structures across the WWTPs. Significant distance decay relationships were observed for the dissimilarity in fungal community structure and altitudinal distance between WWTPs. Additionally, the community evenness increased from 0.25 to 0.7 as the altitude increased. Dissolved oxygen and the C/N ratio were determined to be the most dominant contributors to the variation in fungal community structure via redundancy analysis. The observed data demonstrated the diverse occurrence of fungal species and gave a marked view of fungal community characteristics based on the previously unexplored fungal communities in activated sludge WWTPs.

  11. Biomass, Leaf Area, and Resource Availability of Kudzu Dominated Plant Communities Following Herbicide Treatment

    Energy Technology Data Exchange (ETDEWEB)

    L.T. Rader

    2001-10-01

    Kudzu is an exotic vine that threatens the forests of the southern U.S. Five herbicides were tested with regard to their efficacy in controlling kudzu, community recover was monitored, and interactions with planted pines were studied. The sites selected were old farm sites dominated by kudzu.These were burned following herbicide treatment. The herbicides included triclopyr, clopyralid, metsulfuron, tebuthiuron, and picloram plus 2,4-D. Pine seedlings were planted the following year. Regression equations were developed for predicting biomass and leaf area. Four distinct plant communities resulted from the treatments. The untreated check continued to be kudzu dominated. Blackberry dominated the clopyradid treatment. Metsulfron, trychlopyr and picloram treated sites resulted in herbaceous dominated communities. The tebuthiuron treatment maintained all vegetation low.

  12. A Continuation of Base-Line Studies for Environmentally Monitoring Space Transportation System (STS) at John F. Kennedy Space Center. Volume 1; Terrestrial Community Analysis

    Science.gov (United States)

    Stout, I. J.

    1979-01-01

    Vegetation and small mammal populations in or around the Merritt Island area were studied. Thirty sites were selected from plant communities which were relatively free of logging, grazing, and clearing operations. The vegetative analysis was designed to yield a quantitative description and ecological explanation of the major types of upland vegetation in order to determine the possible future effects of NASA space activities on them. Changes in the relative abundance of small mammal populations, species diversity, standing crop biomass, reproductive activity, and other demographic features were documented in order to gather sufficient information on these populations so that it would be possible to detect even the smaller nonnatural behavior changes in the mammals which might be attributable to NASA space activities.

  13. Evapotranspiration over spatially extensive plant communities in the Big Cypress National Preserve, southern Florida, 2007-2010

    Science.gov (United States)

    Shoemaker, W. Barclay; Lopez, Christian D.; Duever, Michael J.

    2011-01-01

    Evapotranspiration (ET) was quantified over plant communities within the Big Cypress National Preserve (BCNP) using the eddy covariance method for a period of 3 years from October 2007 to September 2010. Plant communities selected for study included Pine Upland, Wet Prairie, Marsh, Cypress Swamp, and Dwarf Cypress. These plant communities are spatially extensive in southern Florida, and thus, the ET measurements described herein can be applied to other humid subtropical locations such as the Everglades.

  14. Use of Medical Plants in Schools Communities from Sinop, Mato Grosso.

    Directory of Open Access Journals (Sweden)

    A. C. M. Urtado

    2013-03-01

    Full Text Available Abstract: This study was conducted in Sinop, Mato Grosso, on two school communities. It was applied semi-structured questionnaires with questions focused on socioeconomic and the use of medicinal plants. It has as finality proved the effective use of medicinal plants on the everyday and a levy of the most used plant. The general profile of the respondents has shown that the women detain the major part of the knowledge, and that pass this uses to the future generations and friends, and find these plants on specialty stores, backyards, supermarket, root stores, bush and fairs. The plants that were found more frequently was (Ruta graveolens L., Babosa (Aloe vera L., Erva-Cidreira (Lippia alba Mill., Erva-Santa-Maria (Chenopodium ambrosioides L., Boldo (Plectranthus amboinicus Spreng., Hortel(Menta x vilosa Huds. e Terramicina (Alternanthera dentata Moench..Keywords: medical plants, Sinop, school.

  15. Microbe-mediated plant-soil feedback in pioneer stages of secondary succession causes long-lasting historical contingency effects in plant community composition.

    NARCIS (Netherlands)

    Kardol, P.; Bezemer, T.M.; Putten, van der W.H.

    2006-01-01

    Soil microbes and soil fauna have been assumed to play a key role in interspecific plant competition and successional community development. It has been suggested that plants can influence their performance by changing the composition of their associated soil communities. Such feedback effects may

  16. Contrasting trait responses in plant communities to experimental and geographic variation in precipitation

    DEFF Research Database (Denmark)

    Sandel, Brody Steven; Goldstein, Leah; Kraft, Nathan

    2010-01-01

    Patterns of precipitation are likely to change significantly in the coming century, with important but poorly understood consequences for plant communities. Experimental and correlative studies may provide insight into expected changes, but little research has addressed the degree of concordance...... between these approaches. We synthesized results from four experimental water addition studies with a correlative analysis of community changes across a large natural precipitation gradient in the United States. We investigated whether community composition, summarized with plant functional traits......, responded similarly to increasing precipitation among studies and sites. In field experiments, increased precipitation favored species with small seed size,short leaf life span and high leaf nitrogen (N) concentration. However, with increasing precipitation along the natural gradient, community composition...

  17. The Communities' research and development programme on decommissioning of nuclear power plants

    International Nuclear Information System (INIS)

    1981-01-01

    This is the first progress report of the European Community's programme (1979-1983) of research on the decommissioning of nuclear power plants. It shows the status of the programme on 31 December 1980. The programme seeks to promote a number of research and development projects as well as the identification of guiding principles. The projects concern the following subjects: long-term integrity of buildings and systems; decontamination for decommissioning purposes; dismantling techniques; treatment of specific waste materials: steel, concrete and graphite; large transport containers for radioactive was produced in the dismantling of nuclear power plants; estimation of the quantities of radioactive wastes arising from decommissioning of nuclear power plants in the Community; influence of nuclear power plant design features on decommissioning

  18. Design of community biogas plant for cooking and lighting from cowdung (a proposal case study)

    International Nuclear Information System (INIS)

    Mekki, Ibtisam I.

    1999-01-01

    A calculation design for community biogas plant was proposed for a village in Sudan consisting 100 families, each consisting of 6 persons (adult). Two children are equivalent to one person. Based on the requirement for cooking and lighting, the community biogas plant is deigned for production of total biogas of 360 m-3 gas per day. This volume of the gas will be produced from total dung per day of 6000kg. This amount of dung will expect to obtained from 600 cows. The actual digester volume equal to 60.5m-3. The layout of the plant was designed of two identical plants, each consisted of 3 digester, i.e. 6digesters will be needed.(Author)

  19. Linking the development and functioning of a carnivorous pitcher plant's microbial digestive community.

    Science.gov (United States)

    Armitage, David W

    2017-11-01

    Ecosystem development theory predicts that successional turnover in community composition can influence ecosystem functioning. However, tests of this theory in natural systems are made difficult by a lack of replicable and tractable model systems. Using the microbial digestive associates of a carnivorous pitcher plant, I tested hypotheses linking host age-driven microbial community development to host functioning. Monitoring the yearlong development of independent microbial digestive communities in two pitcher plant populations revealed a number of trends in community succession matching theoretical predictions. These included mid-successional peaks in bacterial diversity and metabolic substrate use, predictable and parallel successional trajectories among microbial communities, and convergence giving way to divergence in community composition and carbon substrate use. Bacterial composition, biomass, and diversity positively influenced the rate of prey decomposition, which was in turn positively associated with a host leaf's nitrogen uptake efficiency. Overall digestive performance was greatest during late summer. These results highlight links between community succession and ecosystem functioning and extend succession theory to host-associated microbial communities.

  20. Spectral identification of plant communities for mapping of semi-natural grasslands

    DEFF Research Database (Denmark)

    Jacobsen, Anne; Nielsen, Allan Aasbjerg; Ejrnæs, Rasmus

    2000-01-01

    identification of plant communities was based on a hierarchical approach relating the test sites to i) management (Ma) and ii) flora (Fl) using spectral consistency and separability as the main criteria. Evaluation of spectral consistency was based on unsupervised clustering of test sites of Ma classes 1 to 7...... as a measure of plant community heterogeneity within management classes. The spectral analysis as well as the maximum likelihood classification indicated that the source of spectral variation within management classes might be related to vegetation composition....

  1. Training of nuclear power plant personnel in the member states of the European Community

    International Nuclear Information System (INIS)

    Misenta, R.; Matfield, R.S.; Volta, G.; Ancarani, A.; Lhoir, J.

    1981-01-01

    After the Three Mile Island accident the Commission of the European Communities undertook various actions in order to assess the status of the training of nuclear power plant personnel with particular attention to their training for incidents and accidents. This presentation attempts a review of the training situation in the six member states of the European Community together with some other European states, that are operating nuclear power plants. Schemes for the training of control room operators, shift leaders, major European training centres and simulator training will be described

  2. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities.

    Science.gov (United States)

    Uddin, Md Nazim; Robinson, Randall William

    2017-12-01

    Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in both the greenhouse and laboratory by growing associated plants, Melaleuca ericifolia, Rumex conglomeratus, and model plant, Lactuca sativa at varying densities with the allelopathic plant, P. australis, its litter and leachate of P. australis litter. This study investigated the potential interacting influences of allelopathy and resource competition on plant growth-density relationships. In greenhouse, the root exudates mediated effects showed the strongest growth inhibition of M. ericifolia at high density whereas litter mediated results revealed increased growth at medium density treatments compared to low and high density. Again, laboratory experiments related to seed germination and seedling growth of L. sativa and R. conglomeratus exhibited phytotoxicity decreased showing positive growth as plant density increased and vice versa. Overall, the differential effects were observed among experiments but maximum individual plant biomass and some other positive effects on plant traits such as root and shoot length, chlorophyll content occurred at an intermediate density. This was attributed to the sharing of the available phytotoxin among plants at high densities which is compatible to density-dependent phytotoxicity model. The results demonstrated that plant-plant interference is the combined effect of allelopathy and resource competition with many other factors but this experimental design, target-neighbor mixed-culture in combination of plant grown at varying densities with varying

  3. Bacterial communities associated with culex mosquito larvae and two emergent aquatic plants of bioremediation importance.

    Directory of Open Access Journals (Sweden)

    Dagne Duguma

    Full Text Available Microbes are important for mosquito nutrition, growth, reproduction and control. In this study, we examined bacterial communities associated with larval mosquitoes and their habitats. Specifically, we characterized bacterial communities associated with late larval instars of the western encephalitis mosquito (Culextarsalis, the submerged portions of two emergent macrophytes (California bulrush, Schoenoplectuscalifornicus and alkali bulrush, Schoenoplectusmaritimus, and the associated water columns to investigate potential differential use of resources by mosquitoes in different wetland habitats. Using next-generation sequence data from 16S rRNA gene hypervariable regions, the alpha diversity of mosquito gut microbial communities did not differ between pond mesocosms containing distinct monotypic plants. Proteobacteria, dominated by the genus Thorsellia (Enterobacteriaceae, was the most abundant phylum recovered from C. tarsalis larvae. Approximately 49% of bacterial OTUs found in larval mosquitoes were identical to OTUs recovered from the water column and submerged portions of the two bulrushes. Plant and water samples were similar to one another, both being dominated by Actinobacteria, Bacteroidetes, Cyanobacteria, Proteobacteria and Verrucomicrobia phyla. Overall, the bacterial communities within C. tarsalis larvae were conserved and did not change across sampling dates and between two distinct plant habitats. Although Thorsellia spp. dominated mosquito gut communities, overlap of mosquito gut, plant and water-column OTUs likely reveal the effects of larval feeding. Future research will investigate the role of the key indicator groups of bacteria across the different developmental stages of this mosquito species.

  4. Seasonal Variations in the Structure of Phytoplankton Communities near Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, S.-K.; Choi, H.-C.; Moon, H.-T.

    2015-01-01

    To investigate effects of thermal discharge effluent from nuclear power plants on the surrounding marine environment, especially on the phytoplankton community, environmental data gained by seasonal survey around Hanbit and Hanul nuclear power plants during the periods of 11 years from 1999 to 2009 were analysed. The data used were from environmental survey and assessment around Hanbit and Hanul nuclear power plants of Korea during the period of 11 years from 1999 to 2009. The purposes of this study are (1) to evaluate the effect of operation of nuclear power plants on phytoplankton community, (2) to find out whether the thermal discharge affected negatively phytoplankton community, and (3) to evaluate the difference of thermal discharge influence on phytoplankton community between West and East coastal area, Korea. Through this study, (1) quantitative evaluation of the effect of thermal discharge effluent on marine ecology, especially on abundance and biomass of phytoplankton were performed, (2) found that depending on the season, the effect of thermal discharge effluent from nuclear power plant on the marine environment is not always negative (i.e. warm water may increase or prevent decline of abundance in seasons with low temperature such as winter in Hanbit area), and (3) found that same thermal discharge effluent rate to different marine environments, such as west and east coast of Korea, does not result in same effect on the marine ecosystem. (author)

  5. Local Plant Diversity Across Multiple Habitats Supports a Diverse Wild Bee Community in Pennsylvania Apple Orchards.

    Science.gov (United States)

    Kammerer, Melanie A; Biddinger, David J; Rajotte, Edwin G; Mortensen, David A

    2016-02-01

    Wild pollinators supply essential, historically undervalued pollination services to crops and other flowering plant communities with great potential to ensure agricultural production against the loss of heavily relied upon managed pollinators. Local plant communities provision wild bees with crucial floral and nesting resources, but the distribution of floristic diversity among habitat types in North American agricultural landscapes and its effect on pollinators are diverse and poorly understood, especially in orchard systems. We documented floristic diversity in typical mid-Atlantic commercial apple (Malus domestica Borkh.) orchards including the forest and orchard-forest edge ("edge") habitats surrounding orchards in a heterogeneous landscape in south-central Pennsylvania, USA. We also assessed the correlation between plant richness and orchard pollinator communities. In this apple production region, edge habitats are the most species rich, supporting 146 out of 202 plant species recorded in our survey. Plant species richness in the orchard and edge habitats were significant predictors of bee species richness and abundance in the orchard, as well as landscape area of the forest and edge habitats. Both the quantity and quality of forest and edges close to orchards play a significant role in provisioning a diverse wild bee community in this agroecosystem. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Ethnomedicinal plants of the Bauri tribal community of Moulvibazar District, Bangladesh.

    Science.gov (United States)

    Das, Protiva Rani; Islam, Md Tabibul; Mostafa, Mohd Nabil; Rahmatullah, Mohammed

    2013-01-01

    Bangladesh reportedly has more than 100 tribal communities; however, documentation of their medicinal practices is markedly absent. The aim of the present study was to conduct an ethnomedicinal survey among the little known Bauri tribe of Bangladesh, whose tribal medicinal practices are yet to be documented. The survey was carried out among the Bauri tribal community of Purbo Tila village in Moulvibazar District. The community is believed to be the only Bauri community in the country and had four tribal healers who continue their traditional medicinal practices. Interviews of the healers were carried out with the help of a semi-structured questionnaire and the guided field-walk method where the healers took the interviewers on guided field-walks through areas from where they collected their medicinal plants. Here they identified the plants and described their uses. The Bauri healers were observed to use 40 different plant species and one bird species for treatment of ailments such as fever, respiratory tract disorders, pain, gastrointestinal disorders, eye problems like cataract and conjunctivitis, jaundice, abscess, cardiovascular disorders, urinary problems, paralysis, dog bite, snake bite, helminthiasis, lesions on the tongue or lips and piles. Leaves were the major plant part used and constituted 38.3% of total uses followed by fruits at 14.9%. A review of the relevant scientific literature showed that a number of medicinal plants used by the Bauri healers possess pharmacological activities, which were in line with the traditional uses, thus validating their use by the Bauri tribe.

  7. Socioeconomic impacts of nuclear power plant siting: a case study of two New England communities

    International Nuclear Information System (INIS)

    Purdy, B.J.

    1976-01-01

    An examination is presented of the social, economic and political/institutional impacts of two operating nuclear power complexes on two New England communities. The work is one of a series planned to broaden knowledge of the effects of large energy-generating facilities upon the social structure of local communities. Its primary objectives are to investigate and assess social and economic impacts resulting from construction and operation of nuclear power plants and to generate hypotheses about such impacts for future testing

  8. Competition for light and nutrients in layered communities of aquatic plants.

    Science.gov (United States)

    van Gerven, Luuk P A; de Klein, Jeroen J M; Gerla, Daan J; Kooi, Bob W; Kuiper, Jan J; Mooij, Wolf M

    2015-07-01

    Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at high supply of light and nutrients, floating plants always dominate due to their primacy for light, even when submerged plants have lower minimal resource requirements. The model also shows that floating-plant dominance cannot be an alternative stable state in light-limited environments but only in nutrient-limited environments, depending on the plants' resource consumption traits. Compared to unlayered communities, the asymmetry in competition for light-coincident with symmetry in competition for nutrients-leads to fundamentally different results: competition outcomes can no longer be predicted from species traits such as minimal resource requirements ([Formula: see text] rule) and resource consumption. Also, the same two species can, depending on the environment, coexist or be alternative stable states. When applied to two common plant species in temperate regions, both the model and field data suggest that floating-plant dominance is unlikely to be an alternative stable state.

  9. Earthworms drive succession of both plant and Collembola communities in post-mining sites

    Science.gov (United States)

    Mudrák, Ondřej; Uteseny, Karoline; Frouz, Jan

    2016-04-01

    Previous field observations indicated that earthworms promote late-successional plant species and reduce collembolan numbers at post-mining sites in the Sokolov coal mining district (Czech Republic). Here, we established a laboratory pot experiment to test the effect of earthworms (Aporrectodea caliginosa Savigny and Lumbricus rubellus Hoffm.) and litter of low, medium, and high quality (the grass Calamagrostis epigejos, the willow Salix caprea, and the alder Alnus glutinosa, respectively) on late successional plants (grasses Arrhenatherum elatius and Agrostis capillaris, legumes Lotus corniculatus and Trifolium medium, and non-leguminous dicots Centaurea jacea and Plantago lanceolata) in spoil substrate originating from Sokolov post-mining sites and naturally inhabited by abundant numbers of Collembola. The earthworms increased plant biomass, especially that of the large-seeded A. elatius, but reduced the number of plant individuals, mainly that of the small-seeded A. capillaris and both legumes. Litter quality affected plant biomass, which was highest with S. caprea litter, but did not change the number of plant individuals. Litter quality did not modify the effect of earthworms on plants; the effect of litter quality and earthworms was only additive. Species composition of Collembola community was altered by litter quality, but earthworms reduced the number of individuals, increased the number of species, and increased species evenness consistently across the litter qualities. Because the results of this experiment were consistent with the field observations, we conclude that earthworms help drive succession of both plant and Collembola communities on post-mining sites.

  10. Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland)

    OpenAIRE

    Mateusz Wilk; Agnieszka Banach; Julia Pawłowska; Marta Wrzosek

    2014-01-01

    The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2). The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the E...

  11. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Czech Academy of Sciences Publication Activity Database

    Janoušková, Martina; Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Roč. 12, č. 7 (2017), s. 1-21, č. článku e0181525. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LH14285 Institutional support: RVO:67985939 ; RVO:61389030 Keywords : inoculation * arbuscular mycorrhiza * community Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEB-Q) OBOR OECD: Plant sciences, botany; Plant sciences, botany (UEB-Q) Impact factor: 2.806, year: 2016

  12. Ecological effects of transgene persistence on plant communities in the presence and absence of drift levels of glyphosate herbicide

    Science.gov (United States)

    In 2005, plant communities were constructed in outdoor sunlit chambers that contained 3 round tubs having a surface area of 1.2 m2 and a depth of 0.6 m. Six plant types were planted in triplicate using the same spatial arrangement in each tub. Three of the six plant types were se...

  13. Grazing livestock are exposed to terrestrial cyanobacteria

    OpenAIRE

    McGorum , Bruce C; Pirie , R Scott; Glendinning , Laura; McLachlan , Gerry; Metcalf , James S; Banack , Sandra A; Cox , Paul A; Codd , Geoffrey A

    2015-01-01

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in al...

  14. Ethnobotany of wild plants used for starting fermented beverages in Shui communities of southwest China.

    Science.gov (United States)

    Hong, Liya; Zhuo, Jingxian; Lei, Qiyi; Zhou, Jiangju; Ahmed, Selena; Wang, Chaoying; Long, Yuxiao; Li, Feifei; Long, Chunlin

    2015-05-28

    Shui communities of southwest China have an extensive history of using wild plants as starters (Xiaoqu) to prepare fermented beverages that serve important roles in interpersonal relationships and cultural events. While the practice of using wild plants as starters for the preparation of fermented beverages was once prevalent throughout China, this tradition has seen a decline nationally since the 1930s. The traditional technique of preparing fermented beverages from wild plant starters remains well preserved in the Shui communities in southwest China and provides insight on local human-environment interactions and conservation of plant biodiversity for cultural purposes. The present study sought to examine the ethnobotany of wild plants used as starters for the preparation of fermented beverages including an inventory of plants used as a starter in liquor fermentation and associated knowledge and practices. Field surveys were carried out that consisted of semi-structured surveys and plant species inventories. One hundred forty-nine informants in twenty Shui villages were interviewed between July 2012 and October 2014 to document knowledge associated with wild plants used as a liquor fermentation starter. The inventories involved plant voucher specimens and taxonomic identification of plant collections. A total of 103 species in 57 botanical families of wild plants were inventoried and documented that are traditionally used as starters for preparing fermented beverages by Shui communities. The majority of the species (93.2%) have multiple uses in addition to being used as a starter with medicinal purposes being the most prevalent. Shui women are the major harvesters and users of wild plants used as starters for preparing fermented beverages and transfer knowledge orally from mother to daughter. Findings from this study can serve as a basis for future investigation on fermented beverages and foods and associated knowledge and cultural practices. However, with rapid

  15. How plants connect pollination and herbivory networks and their contribution to community stability.

    Science.gov (United States)

    Sauve, Alix M C; Thébault, Elisa; Pocock, Michael J O; Fontaine, Colin

    2016-04-01

    Pollination and herbivory networks have mainly been studied separately, highlighting their distinct structural characteristics and the related processes and dynamics. However, most plants interact with both pollinators and herbivores, and there is evidence that both types of interaction affect each other. Here we investigated the way plants connect these mutualistic and antagonistic networks together, and the consequences for community stability. Using an empirical data set, we show that the way plants connect pollination and herbivory networks is not random and promotes community stability. Analyses of the structure of binary and quantitative networks show different results: the plants' generalism with regard to pollinators is positively correlated to their generalism with regard to herbivores when considering binary interactions, but not when considering quantitative interactions. We also show that plants that share the same pollinators do not share the same herbivores. However, the way plants connect pollination and herbivory networks promotes stability for both binary and quantitative networks. Our results highlight the relevance of considering the diversity of interaction types in ecological communities, and stress the need to better quantify the costs and benefits of interactions, as well as to develop new metrics characterizing the way different interaction types are combined within ecological networks.

  16. Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem.

    Science.gov (United States)

    Dahlin, Kyla M; Asner, Gregory P; Field, Christopher B

    2013-04-23

    Understanding how and why plant communities vary across space has long been a goal of ecology, yet parsing the relative importance of different influences has remained a challenge. Species-specific models are not generalizable, whereas broad plant functional type models lack important detail. Here we consider plant trait patterns at the local scale and ask whether plant chemical traits are more closely linked to environmental gradients or to changes in species composition. We used the visible-to-shortwave infrared (VSWIR) spectrometer of the Carnegie Airborne Observatory to develop maps of four plant chemical traits--leaf nitrogen per mass, leaf carbon per mass, leaf water concentration, and canopy water content--across a diverse Mediterranean-type ecosystem (Jasper Ridge Biological Preserve, CA). For all four traits, plant community alone was the strongest predictor of trait variation (explaining 46-61% of the heterogeneity), whereas environmental gradients accounted for just one fourth of the variation in the traits. This result emphasizes the critical role that species composition plays in mediating nutrient and carbon cycling within and among different communities. Environmental filtering and limits to similarity can act strongly, simultaneously, in a spatially heterogeneous environment, but the local-scale environmental gradients alone cannot account for the variation across this landscape.

  17. Forest Plant and Bird Communities in the Lau Group, Fiji

    Science.gov (United States)

    Franklin, Janet; Steadman, David W.

    2010-01-01

    Background We examined species composition of forest and bird communities in relation to environmental and human disturbance gradients on Lakeba (55.9 km2), Nayau (18.4 km2), and Aiwa Levu (1.2 km2), islands in the Lau Group of Fiji, West Polynesia. The unique avifauna of West Polynesia (Fiji, Tonga, Samoa) has been subjected to prehistoric human-caused extinctions but little was previously known about this topic in the Lau Group. We expected that the degree of human disturbance would be a strong determinant of tree species composition and habitat quality for surviving landbirds, while island area would be unrelated to bird diversity. Methodology/Principal Findings All trees >5 cm diameter were measured and identified in 23 forest plots of 500 m2 each. We recognized four forest species assemblages differentiated by composition and structure: coastal forest, dominated by widely distributed species, and three forest types with differences related more to disturbance history (stages of secondary succession following clearing or selective logging) than to environmental gradients (elevation, slope, rockiness). Our point counts (73 locations in 1 or 2 seasons) recorded 18 of the 24 species of landbirds that exist on the three islands. The relative abundance and species richness of birds were greatest in the forested habitats least disturbed by people. These differences were due mostly to increased numbers of columbid frugivores and passerine insectivores in forests on Lakeba and Aiwa Levu. Considering only forested habitats, the relative abundance and species richness of birds were greater on the small but completely forested (and uninhabited) island of Aiwa Levu than on the much larger island of Lakeba. Conclusions/Significance Forest disturbance history is more important than island area in structuring both tree and landbird communities on remote Pacific islands. Even very small islands may be suitable for conservation reserves if they are protected from human

  18. Impacts of nuclear power plant developments on community service capacity

    International Nuclear Information System (INIS)

    Krannich, R.S.

    1978-03-01

    With the passage of the National Environmental Policy Act in 1969 a legislative mandate was established to assess ''socioeconomic'' as well as environmental consequences of large-scale development projects. However, the developing literature base in the area of socioeconomics has exhibited a pronounced tendency to stress social and economic pathologies associated with the so-called ''boom town'' syndrome. While boom growth and associated problems do appear to provide relevant conceptualizations of the socioeconomic impacts of energy resource development projects in geographically isolated sectors of the western United States, the argument is presented that such a perspective is generally inappropriate when assessing the consequences of nuclear power plant developments. Survey data on 21 nuclear generating facilities are analyzed in order to provide a comparative perspective on socioeconomic consequences and factors which may influence their relative importance

  19. Diversity reduces invasibility in experimental plant communities: the role of plant species

    NARCIS (Netherlands)

    Van Ruijven, J.; De Deyn, G.B.; Berendse, F.

    2003-01-01

    Several studies have presented experimental evidence that diversity reduces invasibility in grassland communities. The interpretation of these results has been disputed recently and it was proposed that sampling effects were responsible for the observed decrease of invasibility with diversity. The

  20. Habitat template approach for green roofs using a native rocky sea coast plant community in Japan.

    Science.gov (United States)

    Nagase, Ayako; Tashiro-Ishii, Yurika

    2018-01-15

    The present study examined whether it is possible to simulate a local herbaceous coastal plant community on a roof, by studying the natural habitats of rocky sea coast plants and their propagation and performance on a green roof. After studying the natural habitat of coastal areas in Izu peninsula, a germination and cutting transplant study was carried out using herbaceous plants from the Jogasaki sea coast. Many plant species did not germinate at all and the use of cuttings was a better method than direct seeding. The green roof was installed in the spring of 2012 in Chiba city. Thirteen plant species from the Jogasaki sea coast, which were successfully propagated, were planted in three kinds of substrate (15 cm depth): pumice, roof tile and commercial green roof substrate. The water drainage was restricted and a reservoir with 5 cm depth of water underlaid the substrate to simulate a similar growing environment to the sea coast. Volcanic rocks were placed as mulch to create a landscape similar to that on the Jogasaki sea coast. Plant coverage on the green roof was measured every month from June 2012 to October 2014. All plants were harvested and their dry shoot weight was measured in December 2014. The type of substrate did not cause significant differences in plant survival and dry shoot weight. Sea coast plant species were divided into four categories: vigorous growth; seasonal change; disappearing after a few years; limited growth. Understanding the ecology of natural habitats was important to simulating a local landscape using native plant communities on the green roof. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities.

    Science.gov (United States)

    Gorzelak, Monika A; Asay, Amanda K; Pickles, Brian J; Simard, Suzanne W

    2015-05-15

    Adaptive behaviour of plants, including rapid changes in physiology, gene regulation and defence response, can be altered when linked to neighbouring plants by a mycorrhizal network (MN). Mechanisms underlying the behavioural changes include mycorrhizal fungal colonization by the MN or interplant communication via transfer of nutrients, defence signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, and also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioural changes in ectomycorrhizal plants depend on environmental cues, the identity of the plant neighbour and the characteristics of the MN. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicate that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems. Published by Oxford University Press on behalf of the Annals of Botany Company.

  2. The factors controlling species density in herbaceous plant communities: An assessment

    Science.gov (United States)

    Grace, J.B.

    1999-01-01

    This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

  3. Plant community responses to simultaneous changes in temperature, nitrogen availability, and invasion.

    Directory of Open Access Journals (Sweden)

    Elise S Gornish

    Full Text Available Increasing rates of change in climate have been observed across the planet and have contributed to the ongoing range shifts observed for many species. Although ecologists are now using a variety of approaches to study how much and through what mechanisms increasing temperature and nutrient pollution may influence the invasions inherent in range shifts, accurate predictions are still lacking.In this study, we conducted a factorial experiment, simultaneously manipulating warming, nitrogen addition and introduction of Pityopsis aspera, to determine how range-shifting species affect a plant community. We quantified the resident community using ordination scores, then used structural equation modeling to examine hypotheses related to how plants respond to a network of experimental treatments and environmental variables. Variation in soil pH explained plant community response to nitrogen addition in the absence of invasion. However, in the presence of invasion, the direct effect of nitrogen on the community was negligible and soil moisture was important for explaining nitrogen effects. We did not find effects of warming on the native plant community in the absence of invasion. In the presence of invasion, however, warming had negative effects on functional richness directly and invasion and herbivory explained the overall positive effect of warming on the plant community.This work highlights the variation in the biotic and abiotic factors responsible for explaining independent and collective climate change effects over a short time scale. Future work should consider the complex and non-additive relationships among factors of climate change and invasion in order to capture more ecologically relevant features of our changing environment.

  4. Summer freezing resistance: a critical filter for plant community assemblies in Mediterranean high mountains

    Directory of Open Access Journals (Sweden)

    David Sánchez Pescador

    2016-02-01

    Full Text Available Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain by measuring their ice nucleation temperature, freezing point (FP, and low-temperature damage (LT50, as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance. The community response to freezing was estimated for each plot as community weighted means (CWMs and functional diversity, and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content, and seed mass. There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the functional diversity of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only the leaf dry matter content correlated negatively with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower functional diversity of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to

  5. Importance of earthworm-seed interactions for the composition and structure of plant communities: A review

    Science.gov (United States)

    Forey, Estelle; Barot, Sébastien; Decaëns, Thibaud; Langlois, Estelle; Laossi, Kam-Rigne; Margerie, Pierre; Scheu, Stefan; Eisenhauer, Nico

    2011-11-01

    Soil seed bank composition and dynamics are crucial elements for the understanding of plant population and community ecology. Earthworms are increasingly recognized as important dispersers and predators of seeds. Through direct and indirect effects they influence either positively or negatively the establishment and survival of seeds and seedlings. Seedling establishment is affected by a variety of earthworm-mediated mechanisms, such as selective seed ingestion and digestion, acceleration or deceleration of germination, and seed transport. Earthworm casts deposited on the soil surface and the entrance of earthworm burrows often contain viable seeds and constitute important regeneration niches for plant seedlings and therefore likely favour specific seed traits. However, the role of earthworms as seed dispersers, mediators of seed bank dynamics and seed predators has not been considered in concert. The overall effect of earthworms on plant communities remains little understood. Most knowledge is based on laboratory studies on temperate species and future work has to explore the biological significance of earthworm-seed interactions under more natural conditions. In this review we summarize the current knowledge on earthworm-seed interactions and discuss factors determining these interactions. We highlight that this interaction may be an underappreciated, yet major driving force for the dynamics of soil seed banks and plant communities which most likely have experienced co-evolutionary processes. Despite the experimental bias, we hypothesize that the knowledge gathered in the present review is of crucial relevance for restoration and conservation ecology. For instance, as earthworms emerge as successful and ubiquitous invaders in various ecosystems, the summarized information might serve as a basis for realistic estimations and modelling of consequences on native plant communities. We depict promising directions of future research and point to the need to consider

  6. Agave salmiana Plant Communities in Central Mexico as Affected by Commercial Use

    Science.gov (United States)

    Martínez Salvador, Martin; Mata-González, Ricardo; Morales Nieto, Carlos; Valdez-Cepeda, Ricardo

    2012-01-01

    Agave salmiana is a native plant species harvested for the commercial production of mezcal ( Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. A. salmiana density was greatest (3,125 plants ha-1) in the short-use areas and less (892 plants ha-1) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were Opuntia leucotricha and Opuntia robusta. A. salmiana density was least (652 plants ha-1) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).

  7. Spatial point process analysis for a plant community with high biodiversity

    DEFF Research Database (Denmark)

    Illian, Janine; Møller, Jesper; Waagepetersen, Rasmus Plenge

    A complex multivariate spatial point pattern for a plant community with high biodiversity is modelled using a hierarchical multivariate point process model. In the model, interactions between plants with different post-fire regeneration strategies are of key interest. We consider initially...... a maximum likelihood approach to inference where problems arise due to unknown interaction radii for the plants. We next demonstrate that a Bayesian approach provides a flexible framework for incorporating prior information concerning the interaction radii. From an ecological perspective, we are able both...

  8. Nematode community shifts in response to experimental warming and canopy conditions are associated with plant community changes in the temperate-boreal forest ecotone.

    Science.gov (United States)

    Thakur, Madhav Prakash; Reich, Peter B; Fisichelli, Nicholas A; Stefanski, Artur; Cesarz, Simone; Dobies, Tomasz; Rich, Roy L; Hobbie, Sarah E; Eisenhauer, Nico

    2014-06-01

    Global climate warming is one of the key forces driving plant community shifts, such as range shifts of temperate species into boreal forests. As plant community shifts are slow to observe, ecotones, boundaries between two ecosystems, are target areas for providing early evidence of ecological responses to warming. The role of soil fauna is poorly explored in ecotones, although their positive and negative effects on plant species can influence plant community structure. We studied nematode communities in response to experimental warming (ambient, +1.7, +3.4 °C) in soils of closed and open canopy forest in the temperate-boreal ecotone of Minnesota, USA and calculated various established nematode indices. We estimated species-specific coverage of understory herbaceous and shrub plant species from the same experimental plots and tested if changes in the nematode community are associated with plant cover and composition. Individual nematode trophic groups did not differ among warming treatments, but the ratio between microbial-feeding and plant-feeding nematodes increased significantly and consistently with warming in both closed and open canopy areas and at both experimental field sites. The increase in this ratio was positively correlated with total cover of understory plant species, perhaps due to increased predation pressure on soil microorganisms causing higher nutrient availability for plants. Multivariate analyses revealed that temperature treatment, canopy conditions and nematode density consistently shaped understory plant communities across experimental sites. Our findings suggest that warming-induced changes in nematode community structure are associated with shifts in plant community composition and productivity in the temperate-boreal forest ecotones.

  9. Ecological assembly rules in plant communities--approaches, patterns and prospects.

    Science.gov (United States)

    Götzenberger, Lars; de Bello, Francesco; Bråthen, Kari Anne; Davison, John; Dubuis, Anne; Guisan, Antoine; Lepš, Jan; Lindborg, Regina; Moora, Mari; Pärtel, Meelis; Pellissier, Loic; Pottier, Julien; Vittoz, Pascal; Zobel, Kristjan; Zobel, Martin

    2012-02-01

    Understanding how communities of living organisms assemble has been a central question in ecology since the early days of the discipline. Disentangling the different processes involved in community assembly is not only interesting in itself but also crucial for an understanding of how communities will behave under future environmental scenarios. The traditional concept of assembly rules reflects the notion that species do not co-occur randomly but are restricted in their co-occurrence by interspecific competition. This concept can be redefined in a more general framework where the co-occurrence of species is a product of chance, historical patterns of speciation and migration, dispersal, abiotic environmental factors, and biotic interactions, with none of these processes being mutually exclusive. Here we present a survey and meta-analyses of 59 papers that compare observed patterns in plant communities with null models simulating random patterns of species assembly. According to the type of data under study and the different methods that are applied to detect community assembly, we distinguish four main types of approach in the published literature: species co-occurrence, niche limitation, guild proportionality and limiting similarity. Results from our meta-analyses suggest that non-random co-occurrence of plant species is not a widespread phenomenon. However, whether this finding reflects the individualistic nature of plant communities or is caused by methodological shortcomings associated with the studies considered cannot be discerned from the available metadata. We advocate that more thorough surveys be conducted using a set of standardized methods to test for the existence of assembly rules in data sets spanning larger biological and geographical scales than have been considered until now. We underpin this general advice with guidelines that should be considered in future assembly rules research. This will enable us to draw more accurate and general

  10. Evolution in plant populations as a driver of ecological changes in arthropod communities.

    Science.gov (United States)

    Johnson, Marc T J; Vellend, Mark; Stinchcombe, John R

    2009-06-12

    Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

  11. Evolution in plant populations as a driver of ecological changes in arthropod communities

    Science.gov (United States)

    Johnson, Marc T.J.; Vellend, Mark; Stinchcombe, John R.

    2009-01-01

    Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

  12. Medicinal wild plant knowledge and gathering patterns in a Mapuche community from North-western Patagonia.

    Science.gov (United States)

    Estomba, Diego; Ladio, Ana; Lozada, Mariana

    2006-01-03

    Medicinal plant use has persisted as a long standing tradition in the Mapuche communities of Southern Argentina and Chile. An ethnobotanical survey was conducted in the rural Curruhuinca community located near the mountain city of San Martin de los Andes, Argentina. Semi-structured interviews were carried out on 22 families in order to examine the present use of medicinal plants and their reputed therapeutic effects. Ecological variables, such as distance to the gathering site and biogeographical origin were also analyzed. Our results showed that the Curruhuinca dwellers cited 89 plant species for medicinal purposes, both of native and exotic origin. They know about 47 native plants, of which they use 40, and they know of 42 exotic medicinal plants of which they use 34. A differential pattern was observed given that only native species, relevant for the traditional Mapuche medicine, were collected at more distant gathering sites. The interviewees mentioned 268 plant usages. Those most frequently reported had therapeutic value for treating digestive ailments (33%), as analgesic/anti-inflammatory (25%) and antitusive (13%). Native species were mainly cited as analgesics, and for gynecological, urinary and "cultural syndrome" effects, whereas exotic species were mainly cited for digestive ailments. The total number of medicinal plants known and used by the interviewees was positively correlated with people's age, indicating that this ancient knowledge tends to disappear in the younger generations.

  13. Plants utilization by the communities of Bharsar and adjoining area of Pauri Garhwal District, Uttarakhand, India

    Directory of Open Access Journals (Sweden)

    ANAND S. BISHT

    2014-04-01

    Full Text Available Bisht AS, Sharma KD. 2014. Plants utilization by the communities of Bharsar and adjoining area of Pauri Garhwal District, Uttarakhand, India. Biodiversitas 15: 92-98. Garhwal Himalaya possesses luxuriant a varied vegetation with in the Himalaya region. Almost every plant has economic value in the form of shelter, food, water, medicine, fuel and industrial products and fodder. Surveys were conducted in entire Bharsar, Pauri Garhwal district of Uttarakhand, India in order to get information on traditional uses of plants by local inhabitants. A total of 169 plants were collected of which 40 species of vegetables, 19 species of forest and agroforestry, 24 species of ornamental flower, 71 species of less known medicinal plants and 15 species of agricultural crops were found economically important as they are used by the people frequently for various purposes.

  14. Waste processing plant eco-auditing system for minimization of environmental risk: European Communities regulatory proposal

    International Nuclear Information System (INIS)

    Brunetti, N.

    1993-01-01

    This paper delineates a system of process control and monitoring checks to be applied to municipal-industrial waste processing and disposal plants to ensure their energy efficient, environmentally safe and reliable operation. In line with European Communities environmental protection strategies, this eco-auditing system requires the preparation of environmental impacts statements on a regular basis during plant operation, as well as, prior to plant start-up. Continuous plant environmental compatibility evaluations are to ascertain: material and energy inputs and outputs; the composition and amounts of exhaust gases released into the atmosphere and the integrity of treatment liquids; control and monitoring instrumentation reliability. The implementation of the auditing system is to be carried out under the supervision of authorized auditing personnel. Waste processing and disposal plants are to make maximum use of energy and materials recovery processes so as to minimize energy consumption and risk to the environment

  15. Plant invasions: Merging the concepts of species invasiveness and community invasibility

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    2006-01-01

    Roč. 30, č. 3 (2006), s. 409-431 ISSN 0309-1333 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * species invasiveness * community invasibility Subject RIV: EF - Botanics Impact factor: 1.278, year: 2006

  16. Does the edge effect influence plant community structure in a tropical dry forest?

    Directory of Open Access Journals (Sweden)

    Diogo Gallo Oliveira

    2013-04-01

    Full Text Available Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.

  17. The Effects of Disturbance History on Ground-Layer Plant Community Composition in British Columbia

    Directory of Open Access Journals (Sweden)

    Michael Ton

    2016-05-01

    Full Text Available Plant communities are sensitive to perturbations and may display alternative recovery pathways depending on disturbance history. In sub-boreal lodgepole pine forests of central interior British Columbia, Canada, fire and logging are two widespread landscape disturbances that overlap in many regions. We asked whether cumulative, short-interval disturbance from logging and fire resulted in different ground-layer plant communities than resulted from fire alone. Using field-collected data, we compared the taxonomic composition and functional traits of 3-year old plant communities that were either harvested 6-to-13 years prior, or not harvested prior to being burned in a large stand-replacing fire. The taxonomic composition diverged between the two treatments, driven primarily by differences in a few key indicator species such as Petasites frigidus and Vaccinium membranaceum. Analysis of individual species’ morphological traits indicated that only a few species vary in size in relation to disturbance history. Our data suggest that a history of forest harvest leaves a subtle footprint on post-fire ground-layer plant communities at early stages of succession.

  18. Establishment of different riparian plant communities from the same soil seed bank

    NARCIS (Netherlands)

    ter Heerdt, Gerhardus

    2016-01-01

    This thesis shows that weather conditions during the first year of establishment, strongly affect the composition of riparian plant communities. This is one of the factors determining if some goals of the Water Framework Directive and Natura 2000, reed beds and accompanying bird species, can be met.

  19. Phytosociology and plant community utilisation by vervet monkeys of the Blydeberg Conservancy, Limpopo Province

    Directory of Open Access Journals (Sweden)

    A.S. Barret

    2006-12-01

    Full Text Available The plant communities of the Blydeberg Conservancy were investigated as part of a research project on the foraging ecology of vervet monkeys Cercopithecus aethiops pygerythrus (senso lato in mixed lowveld bushveld and sour lowveld bushveld areas. To date there are no formal management plans for vervet monkeys. This is attributed to the limited knowledge of vervets and their utilisation of and impacts on ecosystems. From a TWINSPAN classification refined by Braun-Blanquet procedures, ten plant communities that can be placed into four major groups were identified. A classification and description of these communities, including a vegetation map are presented. Diagnostic species as well as prominent and less conspicuous species of tree, shrub, herb and grass strata are outlined. Of the ten available plant communities, the vervets utilised only six during the study period. There was an abundant supply of various food sources throughout the year, with movement patterns mostly coinciding with the fruiting times of several tree and other plant species.

  20. Independent Effects of Invasive Shrubs and Deer Herbivory on Plant Community Dynamics

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Ward

    2016-12-01

    Full Text Available Both invasive species and deer herbivory are recognized as locally important drivers of plant community dynamics. However, few studies have examined whether their effects are synergistic, additive, or antagonistic. At three study areas in southern New England, we examined the interaction of white-tailed deer (Odocoileus virginianus Zimmermann herbivory and three levels of invasive shrub control over seven growing seasons on the dynamics of nine herbaceous and shrub guilds. Although evidence of synergistic interactions was minimal, the separate effects of invasive shrub control and deer herbivory on plant community composition and dynamics were profound. Plant communities remained relatively unchanged where invasive shrubs were not treated, regardless if deer herbivory was excluded or not. With increasing intensity of invasive shrub control, native shrubs and forbs became more dominant where deer herbivory was excluded, and native graminoids became progressively more dominant where deer herbivory remained severe. While deer exclusion and intensive invasive shrub control increased native shrubs and forbs, it also increased invasive vines. Restoring native plant communities in areas with both established invasive shrub thickets and severe deer browsing will require an integrated management plan to eliminate recalcitrant invasive shrubs, reduce deer browsing intensity, and quickly treat other opportunistic invasive species.

  1. Resurvey of historical vegetation plots: a tool for understanding long-term dynamics of plant communities

    Czech Academy of Sciences Publication Activity Database

    Hédl, Radim; Brnhardt-Römermann, M.; Grytnes, J.-A.; Jurasinski, G.; Ewald, J.

    2017-01-01

    Roč. 20, č. 2 (2017), s. 161-163 ISSN 1402-2001 Institutional support: RVO:67985939 Keywords : global change * plant communities * plot resurveys Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 2.474, year: 2016

  2. Volatile-mediated suppression of plant pathogens is related to soil properties and microbial community composition

    NARCIS (Netherlands)

    Van Agtmaal, M.; Straathof, A.L.; Termorshuizen, Aad J; Lievens, Bart; Hoffland, Ellis; De Boer, W.

    2018-01-01

    There is increasing evidence that the soil microbial community produces a suite of volatile organic compounds that suppress plant pathogens. However, it remains unknown which soil properties and management practices influence volatile-mediated pathogen suppression. The aim of this study was to

  3. Plants Rather than Mineral Fertilization Shape Microbial Community Structure and Functional Potential in Legacy Contaminated Soil

    Czech Academy of Sciences Publication Activity Database

    Rídl, Jakub; Kolář, Michal; Strejček, M.; Strnad, Hynek; Štursa, P.; Pačes, Jan; Macek, T.; Uhlík, O.

    2016-01-01

    Roč. 7, JUN 24 (2016), č. článku 995. ISSN 1664-302X R&D Projects: GA ČR GA13-28283S Institutional support: RVO:68378050 Keywords : microbial community structure * plants * fertilization * contaminated soil * functional potential Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.076, year: 2016

  4. Volatile-mediated suppression of plant pathogens is related to soil properties and microbial community composition

    NARCIS (Netherlands)

    Agtmaal, van Maaike; Straathof, Angela L.; Termorshuizen, Aad; Lievens, Bart; Hoffland, Ellis; Boer, de Wietse

    2018-01-01

    There is increasing evidence that the soil microbial community produces a suite of volatile organic compounds that suppress plant pathogens. However, it remains unknown which soil properties and management practices influence volatile-mediated pathogen suppression. The aim of this study was to

  5. Plant Community and Soil Environment Response to Summer Fire in the Northern Great Plains

    Science.gov (United States)

    Fire is a keystone process in many ecosystems, especially grasslands. However, documentation of plant community and soil environment responses to fire is limited for semiarid grasslands relative to that for mesic grasslands. Replicated summer fire research is lacking, but much needed because summe...

  6. Plant secondary metabolite-induced shifts in bacterial community structure and degradative ability in contaminated soil

    Czech Academy of Sciences Publication Activity Database

    Uhlík, O.; Musilová, L.; Rídl, Jakub; Hroudová, Miluše; Vlček, Čestmír; Koubek, J.; Holečková, M.; Mackova, M.; Macek, T.

    2013-01-01

    Roč. 97, č. 20 (2013), s. 9245-9256 ISSN 0175-7598 Grant - others:EK(XE) 265946; GA MŠk(CZ) ME10041 Institutional support: RVO:68378050 Keywords : plant secondary metabolites (PSM) * bacterial community * metabolic activity * bioremediation * pyrosequencing Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.811, year: 2013

  7. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion

    Science.gov (United States)

    B. M. Connolly; D. E. Pearson; R. N. Mack

    2014-01-01

    Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food...

  8. Dissimilar response of plant and soil biota communities to long-term nutrient adition in grasslands

    NARCIS (Netherlands)

    Wal, van der A.; Geerts, R.H.E.M.; Korevaar, H.; Schouten, A.J.; Jagers op Akkerhuis, G.A.J.M.; Rutgers, M.; Mulder, C.

    2009-01-01

    The long-term effect of fertilizers on plant diversity and productivity is well known, but long-term effects on soil biota communities have received relatively little attention. Here, we used an exceptional long-lasting (>40 years) grassland fertilization experiment to investigate the long-term

  9. Metagenomic analysis of an ecological wastewater treatment plant's microbial communities and their potential to metabolize pharmaceuticals.

    Science.gov (United States)

    Balcom, Ian N; Driscoll, Heather; Vincent, James; Leduc, Meagan

    2016-01-01

    Pharmaceuticals and other micropollutants have been detected in drinking water, groundwater, surface water, and soil around the world. Even in locations where wastewater treatment is required, they can be found in drinking water wells, municipal water supplies, and agricultural soils. It is clear conventional wastewater treatment technologies are not meeting the challenge of the mounting pressures on global freshwater supplies. Cost-effective ecological wastewater treatment technologies have been developed in response. To determine whether the removal of micropollutants in ecological wastewater treatment plants (WWTPs) is promoted by the plant-microbe interactions, as has been reported for other recalcitrant xenobiotics, biofilm microbial communities growing on the surfaces of plant roots were profiled by whole metagenome sequencing and compared to the microbial communities residing in the wastewater. In this study, the concentrations of pharmaceuticals and personal care products (PPCPs) were quantified in each treatment tank of the ecological WWTP treating human wastewater at a highway rest stop and visitor center in Vermont. The concentrations of detected PPCPs were substantially greater than values reported for conventional WWTPs likely due to onsite recirculation of wastewater. The greatest reductions in PPCPs concentrations were observed in the anoxic treatment tank where Bacilli dominated the biofilm community. Benzoate degradation was the most abundant xenobiotic metabolic category identified throughout the system. Collectively, the microbial communities residing in the wastewater were taxonomically and metabolically more diverse than the immersed plant root biofilm. However, greater heterogeneity and higher relative abundances of xenobiotic metabolism genes was observed for the root biofilm.

  10. Properties of native plant communities do not determine exotic success during early forest succession

    Science.gov (United States)

    Aldo Compagnoni; Charles B. Halpern

    2009-01-01

    Considerable research has been devoted to understanding how plant invasions are influenced by properties of the native community and to the traits of exotic species that contribute to successful invasion. Studies of invasibility are common in successionally stable grasslands, but rare in recently disturbed or seral forests. We used 16 years of species richness and...

  11. Squared Euclidean distance: a statistical test to evaluate plant community change

    Science.gov (United States)

    Raymond D. Ratliff; Sylvia R. Mori

    1993-01-01

    The concepts and a procedure for evaluating plant community change using the squared Euclidean distance (SED) resemblance function are described. Analyses are based on the concept that Euclidean distances constitute a sample from a population of distances between sampling units (SUs) for a specific number of times and SUs. With different times, the distances will be...

  12. Blue oak plant communities of southern San Luis Obispo and northern Santa Barbara Counties, California

    Science.gov (United States)

    Mark I. Borchert; Nancy D. Cunha; Patricia C. Krosse; Marcee L. Lawrence

    1993-01-01

    An ecological classification system has been developed for the Pacific Southwest Region of the Forest Service. As part of that classification effort, blue oak (Quercus douglasii) woodlands and forests of southern San Luis Obispo and northern Santa Barbara Counties in Los Padres National Forest were classified into I3 plant communities using...

  13. Negative Plant–Soil Feedback and Positive Species Interaction in a Herbaceous Plant Community

    NARCIS (Netherlands)

    Bonanomi, G.; Rietkerk, M.G.; Dekker, S.C.; Mazzoleni, S.

    2005-01-01

    Increasing evidence shows that facilitative interaction and negative plant–soil feedback are driving factors of plant population dynamics and community processes. We studied the intensity and the relative impact of negative feedback on clonal growth and seed germination of Scirpus holoschoenus, a

  14. Phyllosphere Microbiota Composition and Microbial Community Transplantation on Lettuce Plants Grown Indoors

    Science.gov (United States)

    Williams, Thomas R.

    2014-01-01

    ABSTRACT The aerial surfaces of plants, or phyllosphere, are microbial habitats important to plant and human health. In order to accurately investigate microbial interactions in the phyllosphere under laboratory conditions, the composition of the phyllosphere microbiota should be representative of the diversity of microorganisms residing on plants in nature. We found that Romaine lettuce grown in the laboratory contained 10- to 100-fold lower numbers of bacteria than age-matched, field-grown lettuce. The bacterial diversity on laboratory-grown plants was also significantly lower and contained relatively higher proportions of Betaproteobacteria as opposed to the Gammaproteobacteria-enriched communities on field lettuce. Incubation of field-grown Romaine lettuce plants in environmental growth chambers for 2 weeks resulted in bacterial cell densities and taxa similar to those on plants in the field but with less diverse bacterial populations overall. In comparison, the inoculation of laboratory-grown Romaine lettuce plants with either freshly collected or cryopreserved microorganisms recovered from field lettuce resulted in the development of a field-like microbiota on the lettuce within 2 days of application. The survival of an inoculated strain of Escherichia coli O157:H7 was unchanged by microbial community transfer; however, the inoculation of E. coli O157:H7 onto those plants resulted in significant shifts in the abundance of certain taxa. This finding was strictly dependent on the presence of a field-associated as opposed to a laboratory-associated microbiota on the plants. Phyllosphere microbiota transplantation in the laboratory will be useful for elucidating microbial interactions on plants that are important to agriculture and microbial food safety. PMID:25118240

  15. Endemic plants harbour specific Trichoderma communities with an exceptional potential for biocontrol of phytopathogens.

    Science.gov (United States)

    Zachow, Christin; Berg, Christian; Müller, Henry; Monk, Jana; Berg, Gabriele

    2016-10-10

    Trichoderma strains exhibit enormous potential for applications in biotechnology, in particular as biocontrol agents against pathogens. However, little is known about the diversity of plant-associated Trichoderma communities at a global scale and their antagonistic spectrum. In order to gather information about structure and function, we compared Trichoderma biomes of endemic (Aeonium, Diospyros, Hebe, Rhododendron) and cosmopolitan plants (Zea mays) in a global study encompassing the area Northwest Africa to New Zealand via the European Alps and Madagascar. At the quantitative level we found no differences between cosmopolitan and endemic plants. Statistically significant differences were detected at the qualitative level: Trichoderma populations of endemic plants were highly specific and diverse with hot spots appearing in Madagascar and New Zealand. By contrast, maize plants from all sites shared the majority of Trichoderma species (65.5%). Interestingly, the high above ground biodiversity in ecosystems containing endemic plants was confirmed by a high below ground Trichoderma diversity. Despite the differences, we found a global Trichoderma core community shared by all analysed plants, which was dominated by T. koningii and T. koningiopsis. Amplicon-based network analyses revealed a high similarity between maize Trichoderma grown world-wide and distinct populations of endemic plants. Furthermore, Trichoderma strains from endemic plants showed a higher antagonistic activity against fungal pathogens compared to maize-associated strains. Our results showed that endemic plants are associated with a specific Trichoderma microbiome which possesses a high antagonistic activity indicating that it has potential to be used for biocontrol purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Indigenous uses of ethnomedicinal plants among forest-dependent communities of Northern Bengal, India.

    Science.gov (United States)

    Raj, Antony Joseph; Biswakarma, Saroj; Pala, Nazir A; Shukla, Gopal; Vineeta; Kumar, Munesh; Chakravarty, Sumit; Bussmann, Rainer W

    2018-01-26

    Traditional knowledge on ethnomedicinal plant is slowly eroding. The exploration, identification and documentation on utilization of ethnobotanic resources are essential for restoration and preservation of ethnomedicinal knowledge about the plants and conservation of these species for greater interest of human society. The study was conducted at fringe areas of Chilapatta Reserve Forest in the foothills of the eastern sub-Himalayan mountain belts of West Bengal, India, from December 2014 to May 2016. Purposive sampling method was used for selection of area. From this area which is inhabited by aboriginal community of Indo-Mongoloid origin, 400 respondents including traditional medicinal practitioners were selected randomly for personal interview schedule through open-ended questionnaire. The questionnaire covered aspects like plant species used as ethnomedicines, plant parts used, procedure for dosage and therapy. A total number of 140 ethnomedicinal species was documented, in which the tree species (55) dominated the lists followed by herbs (39) and shrubs (30). Among these total planted species used for ethnomedicinal purposes, 52 species were planted, 62 species growing wild or collected from the forest for use and 26 species were both wild and planted. The present study documented 61 more planted species as compared to 17 planted species documented in an ethnomedicinal study a decade ago. The documented species were used to treat 58 human diseases/ailments including nine species used to eight diseases/ailments of domestic animals. Stomach-related problems were treated by maximum number of plants (40 species) followed by cuts and wounds with 27 plant species and least with one species each for 17 diseases or ailments. Maximum number of 12 diseases/ailments was cured by Melia azedarach followed by Centella asiatica and Rauvolfia serpentina which were used to cure 11 diseases/ailments each. The list of 140 plant species indicates that the Chilapatta Reserve Forest

  17. The most used medicinal plants by communities in Mahaboboka, Amboronabo, Mikoboka, Southwestern Madagascar.

    Science.gov (United States)

    Randrianarivony, Tabita N; Ramarosandratana, Aro Vonjy; Andriamihajarivo, Tefy H; Rakotoarivony, Fortunat; Jeannoda, Vololoniaina H; Randrianasolo, Armand; Bussmann, Rainer W

    2017-03-09

    This paper reports a study undertaken in three remote communities (Mahaboboka, Amboronabo, Mikoboka), located in Sakaraha, Southwestern Madagascar. Not only villages are far away from sanitary infrastructures and doctors but drugs and consulting fees are unaffordable to villagers. They rely essentially on natural resources for health care as for most of rural areas in Madagascar. This paper aims to document medicinal plants used by communities in Sakaraha and to present the most important plant species used in traditional medicine. Semi - structured interview was conducted within 214 informants in 34 villages of the study area. Different ailments encountered in the site study were classified in various categories. For data analysis, frequency of citation (Fq), Informant Consensus Factor (Fic), Fidelity Level (FL) and Use Value (UV) were assessed to find agreement among informants about the use of plants as remedies. Mann-Whitney, Kruskall-Wallis and Spearman correlation tests were performed to determine use of medicinal plants following social status of informants. A total of 235 medicinal plant species belonging to 198 genera and 75 families were inventoried. The richest families in species used for medicinal purposes were: Fabaceae, Apocynaceae, Rubiaceae, Euphorbiaceae, Asteraceae, and Poaceae. Plant species cited by informants were used to treat 76 various ailments classified in 13 categories. Leaves and leafy twigs were the most used plant parts and decoction was the mostly cited way of preparation of these medicinal plants species. In average, local people cited 6.7 ± 6.03 medicinal taxa among them, Cedrelopsis grevei is the most cited medicinal plants (Fq. 0.28). With Cedrelopsis grevei (UV = 0.48), Henonia scoparia (UV = 0.43) are mostly used species. Leonotis nepetifolia (FL = 96%) and Strychnos henningsii (FL = 92%) are plant species claimed by high percentage of informants to treat the Digestive System Disorder. This study

  18. Terrestrial invertebrates in the Rhynie chert ecosystem.

    Science.gov (United States)

    Dunlop, Jason A; Garwood, Russell J

    2018-02-05

    The Early Devonian Rhynie and Windyfield cherts remain a key locality for understanding early life and ecology on land. They host the oldest unequivocal nematode worm (Nematoda), which may also offer the earliest evidence for herbivory via plant parasitism. The trigonotarbids (Arachnida: Trigonotarbida) preserve the oldest book lungs and were probably predators that practiced liquid feeding. The oldest mites (Arachnida: Acariformes) are represented by taxa which include mycophages and predators on nematodes today. The earliest harvestman (Arachnida: Opiliones) includes the first preserved tracheae, and male and female genitalia. Myriapods are represented by a scutigeromorph centipede (Chilopoda: Scutigeromorpha), probably a cursorial predator on the substrate, and a putative millipede (Diplopoda). The oldest springtails (Hexapoda: Collembola) were probably mycophages, and another hexapod of uncertain affinities preserves a gut infill of phytodebris. The first true insects (Hexapoda: Insecta) are represented by a species known from chewing (non-carnivorous?) mandibles. Coprolites also provide insights into diet, and we challenge previous assumptions that several taxa were spore-feeders. Rhynie appears to preserve a largely intact community of terrestrial animals, although some expected groups are absent. The known fossils are (ecologically) consistent with at least part of the fauna found around modern Icelandic hot springs.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Author(s).

  19. Use and management of traditional medicinal plants by Maale and Ari ethnic communities in southern Ethiopia

    Science.gov (United States)

    2014-01-01

    Background Around 80% of the people of Ethiopia are estimated to be relying on medicinal plants for the treatment of different types of human health problems. The purpose of this study was to describe and analyse the use and management of medicinal plants used for the treatment of human health problems by the Maale and Ari communities in southern Ethiopia. Methods Quantitative and qualitative ethnobotanical field inquiries and analytical methods including individual and focus group discussions (18), observations, individual interviews (n = 74), preference ranking and paired comparison were used. Data were collected in three study sites and from two markets; the latter surveyed every 15 days from February 2011 to February 2012. Results A total of 128 medicinal plant species, belonging to 111 genera and 49 families, used as herbal medicine by Maale and Ari communities were documented. Predominantly harvested plant parts were leaves, which are known to have relatively low impact on medicinal plant resources. Species with high familiarity indices included Solanum dasyphyllum, Indigofera spicata, Ruta chalepensis, Plumbago zeylanica and Meyna tetraphylla. Low Jaccards similarity indices (≤ 0.33) indicated little correspondence in medicinal plant use among sites and between ethnic communities. The dominant ways of medicinal plant knowledge acquisition and transfer is vertical: from parents to children through oral means. Gender and site significantly influenced the number of human medicinal plants known currently in the study sites. Age was only a factor of significance in Maale. Marketing of medicinal plants harvested from wild and semi-wild stands is not common. Expansion of agricultural land and lack of cultivation efforts by local communities are mentioned by locals to affect the availability of medicinal plant resources. Conclusion S. dasyphyllum, I. spicata, P. zeylanica, M. tetraphylla, and Oxalis radicosa need to be considered for phytochemical and

  20. Water Source Utilization of Hammock and Pine Rockland Plant Communities in the Everglades, USA.

    Science.gov (United States)

    Saha, A. K.; Sternberg, L.; Miralles-Wilhelm, F.

    2007-12-01

    South Florida has a mosaic of plant communities resulting from topographical differences, spatially varying hydroperiods and fire. The only plant communities not flooded in the wet season are hardwood hammocks and often pine rocklands. Natural fires burn off litter accumulated in pine rocklands, with the exception of organic matter in sinkholes in the limestone bedrock. This relative lack of soil is thought to constrain pineland plants in the Everglades to depend upon groundwater that is typically low in nutrients. In contrast, adjoining hardwood hammocks have accumulated an organic soil layer that traps rainwater and nutrients. Plants in hammocks may be able to utilize this water and thereby access nutrients present in the litter. Hammocks are thus viewed as localized areas of high nutrients and instances of vegetation feedback upon the oligotrophic everglades landscape enabling establishment and survival of flood-intolerant tropical hardwood species. This study examines water source use and couples it to foliar nutrient concentrations of plants found in hammocks and pinelands. We examined the δ2H and δ18O of stem waters in plants in Everglades National Park and compared those with the δ2H and δ18O of potential water sources. In the wet season hammock plants accessed both groundwater and water in the surface organic soil layer while in the dry season they relied more on groundwater. A similar seasonal shift was observed in pineland plants; however groundwater constituted a much higher proportion of total water uptake throughout the year under observation. Concomitant with differential water utilization by hammock and pineland plant communities, we observed hammock plants having a significantly higher annual mean foliar N and P concentration than pineland plants. Most hammock species are intolerant of flooded soils and are thus constrained by the high water table in the wet season, yet access the lowered groundwater table in the dry season due to drying up of

  1. Lags in the response of mountain plant communities to climate change.

    Science.gov (United States)

    Alexander, Jake M; Chalmandrier, Loïc; Lenoir, Jonathan; Burgess, Treena I; Essl, Franz; Haider, Sylvia; Kueffer, Christoph; McDougall, Keith; Milbau, Ann; Nuñez, Martin A; Pauchard, Aníbal; Rabitsch, Wolfgang; Rew, Lisa J; Sanders, Nathan J; Pellissier, Loïc

    2018-02-01

    Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: "dispersal lags" affecting plant species' spread along elevational gradients, "establishment lags" following their arrival in recipient communities, and "extinction lags" of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species' range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide. © 2017 John Wiley & Sons Ltd.

  2. Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

    International Nuclear Information System (INIS)

    Pellissier, Loïc; Wisz, Mary S; Strandberg, Beate; Damgaard, Christian

    2014-01-01

    Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase