WorldWideScience

Sample records for plant diversity gradient

  1. Resource availability controls fungal diversity across a plant diversity gradient

    Science.gov (United States)

    Waldrop, M.P.; Zak, D.R.; Blackwood, C.B.; Curtis, C.D.; Tilman, D.

    2006-01-01

    Despite decades of research, the ecological determinants of microbial diversity remain poorly understood. Here, we test two alternative hypotheses concerning the factors regulating fungal diversity in soil. The first states that higher levels of plant detritus production increase the supply of limiting resources (i.e. organic substrates) thereby increasing fungal diversity. Alternatively, greater plant diversity increases the range of organic substrates entering soil, thereby increasing the number of niches to be filled by a greater array of heterotrophic fungi. These two hypotheses were simultaneously examined in experimental plant communities consisting of one to 16 species that have been maintained for a decade. We used ribosomal intergenic spacer analysis (RISA), in combination with cloning and sequencing, to quantify fungal community composition and diversity within the experimental plant communities. We used soil microbial biomass as a temporally integrated measure of resource supply. Plant diversity was unrelated to fungal diversity, but fungal diversity was a unimodal function of resource supply. Canonical correspondence analysis (CCA) indicated that plant diversity showed a relationship to fungal community composition, although the occurrence of RISA bands and operational taxonomic units (OTUs) did not differ among the treatments. The relationship between fungal diversity and resource availability parallels similar relationships reported for grasslands, tropical forests, coral reefs, and other biotic communities, strongly suggesting that the same underlying mechanisms determine the diversity of organisms at multiple scales. ?? 2006 Blackwell Publishing Ltd/CNRS.

  2. Plant-animal interactions in two forest herbs along a tree and herb diversity gradient

    NARCIS (Netherlands)

    Vockenhuber, E.; Kabouw, P.; Tscharntke, T.; Scherber, C.

    2013-01-01

    Background: Plant diversity can influence numerous ecosystem processes, including plant–animal interactions, which, in turn, will affect plant growth and fitness. At present, little is known on how plant–animal interactions in forests respond to gradients in tree and herb-layer diversity. Aims: To q

  3. Plant Species Diversity along an Altitudinal Gradient of Bhabha Valley in Western Himalaya

    Institute of Scientific and Technical Information of China (English)

    Amit Chawla; S. Rajkumar; K.N. Singh; Brij Lal; R.D. Singh; A. K. Thukral

    2008-01-01

    The present study highlights the rich species diversity of higher plants in the Bhabha Valley of western Himalaya in India. The analysis of species diversity revealed that a total of 313 species of higher plants inhabit the valley with a charactersfic of moist alpine shrub vegetation. The herbaceous life forms dominate and increase with increasing altitude. The major representations are from the families Asteraceae, Rosaceae, Lamiaceae and Poaceae, suggesting thereby the alpine meadow nature of the study area. The effect of altitude on species diversity displays a hump-shaped curve which may be attributed to increase in habitat diversity at the median ranges and relatively less habitat diversity at higher altitudes. The anthropogenic pressure at lower altitudes results in low plant diversity towards the bottom of the valley with most of the species being exotic in nature. Though the plant diversity is less at higher altitudinal ranges, the uniqueness is relatively high with high species replacement rates. More than 90% of variability in the species diversity could be explained using appropriate quantitative and statistical analysis along the altitudinal gradient. The valley harbours 18 threatened and 41 endemic species, most of which occur at higher altitudinal gradients due to habitat specificity.

  4. Biomass and diversity of dry alpine plant communities along altitudinal gradients in the Himalayas

    NARCIS (Netherlands)

    Namgail, T.; Rawat, G.S.; Mishra, C.; Wieren, van S.E.; Prins, H.H.T.

    2012-01-01

    A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood.We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western

  5. Facilitation contributes to Mediterranean woody plant diversity but does not shape the diversity-productivity relationship along aridity gradients.

    Science.gov (United States)

    Rey, Pedro J; Alcántara, Julio M; Manzaneda, Antonio J; Sánchez-Lafuente, Alfonso M

    2016-07-01

    The diversity-productivity relationship (humped-back model (HBM)) and the stress-gradient (SGH) hypotheses may be connected when productivity is limited primarily by aridity. We analytically connect both hypotheses and assess the contribution of facilitation to woody plant richness along the aridity gradient of the Western Mediterranean floristic region. We monitored regeneration niches of woody plants, obtaining rarefied species richness and plant relative interaction indices in 54 forests and scrublands in a 1750-km geographical range across Spain, Morocco and the Canary Islands. We verified the monotonic increase in facilitation with aridity postulated by SGH and the humped-shape pattern of species richness expected from HBM, which became manifest after expanding the aridity gradient or crossing vegetation types. Along the gradient, interaction balance turned into facilitation earlier in forest than in scrublands. The effects of aridity and interaction balance on species diversity were additive rather than interdependent. Facilitation is an important driver of woody species richness at macroecological scales because it added up to diversity in most sites, with enhanced contribution with increased stress. The HBM was not shaped by species interactions. Results suggest that facilitation may act in Mediterranean vegetation buffering against critical transitions between states allowing woody plant communities to cope with the rise in aridity expected with global warming.

  6. Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients

    Science.gov (United States)

    Spasojevic, Marko J.; Grace, James B.; Harrison, Susan; Damschen, Ellen Ingman

    2013-01-01

    1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic study by R. H. Whittaker (1960), herb species richness declined from mesic (cool, moist, northerly) slopes to xeric (hot, dry, southerly) slopes. Building on this dataset, we measured four plant functional traits (plant height, specific leaf area, leaf water content and foliar C:N) and used them to calculate three functional diversity metrics (functional richness, evenness, and dispersion). We then used a structural equation model to ask if ‘functional diversity’ (modeled as the joint responses of richness, evenness, and dispersion) could explain the observed relationship of topographic climate gradients to species richness. We then repeated our model examining the functional diversity of each of the four traits individually. 3. Consistent with the physiological tolerance hypothesis, we found that functional diversity was higher in more favorable climatic conditions (mesic slopes), and that multivariate functional diversity mediated the relationship of the topographic climate gradient to plant species richness. We found similar patterns for models focusing on individual trait functional diversity of leaf water content and foliar C:N. 4. Synthesis. Our results provide trait-based support for the physiological tolerance hypothesis, suggesting that benign climates support more species because they allow for a wider range of functional strategies.

  7. Biomass and diversity of dry alpine plant communities along altitudinal gradients in the Himalayas

    Science.gov (United States)

    Namgail, T.; Rawat, G.S.; Mishra, C.; van Wieren, S.E.; Prins, H.H.T.

    2012-01-01

    A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood. We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western Himalaya. We used generalized linear and generalized additive models to assess the relationship between these vegetation parameters and altitude. We found a hump-shaped relationship between aboveground phytomass and altitude. We suspect that this is engendered by low rainfall and trampling/excessive grazing at lower slopes by domestic livestock, and low temperature and low nutrient levels at higher slopes. We also found a unimodal relationship between plant species-richness and altitude at a single mountain as well as at the scale of entire Ladakh. The species-richness at the single mountain peaked between 5,000 and 5,200 m, while it peaked between 3,500 and 4,000 m at entire Ladakh level. Perhaps biotic factors such as grazing and precipitation are, respectively, important in generating this pattern at the single mountain and entire Ladakh. ?? 2011 The Author(s).

  8. Modeling terrestrial carbon and water dynamics across climatic gradients: does plant trait diversity matter?

    Science.gov (United States)

    Pappas, Christoforos; Fatichi, Simone; Burlando, Paolo

    2016-01-01

    Plant trait diversity in many vegetation models is crudely represented using a discrete classification of a handful of 'plant types' (named plant functional types; PFTs). The parameterization of PFTs reflects mean properties of observed plant traits over broad categories ignoring most of the inter- and intraspecific plant trait variability. Taking advantage of a multivariate leaf-trait distribution (leaf economics spectrum), as well as documented plant drought strategies, we generate an ensemble of hypothetical species with coordinated attributes, rather than using few PFTs. The behavior of these proxy species is tested using a mechanistic ecohydrological model that translates plant traits into plant performance. Simulations are carried out for a range of climates representative of different elevations and wetness conditions in the European Alps. Using this framework we investigate the sensitivity of ecosystem response to plant trait diversity and compare it with the sensitivity to climate variability. Plant trait diversity leads to highly divergent vegetation carbon dynamics (fluxes and pools) and to a lesser extent water fluxes (transpiration). Abiotic variables, such as soil water content and evaporation, are only marginally affected. These results highlight the need for revising the representation of plant attributes in vegetation models. Probabilistic approaches, based on observed multivariate whole-plant trait distributions, provide a viable alternative.

  9. Commercial Plant Production and Consumption Still Follow the Latitudinal Gradient in Species Diversity despite Economic Globalization.

    Science.gov (United States)

    Nelson, Erik J; Helmus, Matthew R; Cavender-Bares, Jeannine; Polasky, Stephen; Lasky, Jesse R; Zanne, Amy E; Pearse, William D; Kraft, Nathan J B; Miteva, Daniela A; Fagan, William F

    2016-01-01

    Increasing trade between countries and gains in income have given consumers around the world access to a richer and more diverse set of commercial plant products (i.e., foods and fibers produced by farmers). According to the economic theory of comparative advantage, countries open to trade will be able to consume more-in terms of volume and diversity-if they concentrate production on commodities that they can most cost-effectively produce, while importing goods that are expensive to produce, relative to other countries. Here, we perform a global analysis of traded commercial plant products and find little evidence that increasing globalization has incentivized agricultural specialization. Instead, a country's plant production and consumption patterns are still largely determined by local evolutionary legacies of plant diversification. Because tropical countries harbor a greater diversity of lineages across the tree of life than temperate countries, tropical countries produce and consume a greater diversity of plant products than do temperate countries. In contrast, the richer and more economically advanced temperate countries have the capacity to produce and consume more plant species than the generally poorer tropical countries, yet this collection of plant species is drawn from fewer branches on the tree of life. Why have countries not increasingly specialized in plant production despite the theoretical financial incentive to do so? Potential explanations include the persistence of domestic agricultural subsidies that distort production decisions, cultural preferences for diverse local food production, and that diverse food production protects rural households in developing countries from food price shocks. Less specialized production patterns will make crop systems more resilient to zonal climatic and social perturbations, but this may come at the expense of global crop production efficiency, an important step in making the transition to a hotter and more

  10. Commercial Plant Production and Consumption Still Follow the Latitudinal Gradient in Species Diversity despite Economic Globalization

    Science.gov (United States)

    Nelson, Erik J.; Helmus, Matthew R.; Cavender-Bares, Jeannine; Polasky, Stephen; Lasky, Jesse R.; Zanne, Amy E.; Pearse, William D.; Kraft, Nathan J. B.; Miteva, Daniela A.; Fagan, William F.

    2016-01-01

    Increasing trade between countries and gains in income have given consumers around the world access to a richer and more diverse set of commercial plant products (i.e., foods and fibers produced by farmers). According to the economic theory of comparative advantage, countries open to trade will be able to consume more–in terms of volume and diversity–if they concentrate production on commodities that they can most cost-effectively produce, while importing goods that are expensive to produce, relative to other countries. Here, we perform a global analysis of traded commercial plant products and find little evidence that increasing globalization has incentivized agricultural specialization. Instead, a country’s plant production and consumption patterns are still largely determined by local evolutionary legacies of plant diversification. Because tropical countries harbor a greater diversity of lineages across the tree of life than temperate countries, tropical countries produce and consume a greater diversity of plant products than do temperate countries. In contrast, the richer and more economically advanced temperate countries have the capacity to produce and consume more plant species than the generally poorer tropical countries, yet this collection of plant species is drawn from fewer branches on the tree of life. Why have countries not increasingly specialized in plant production despite the theoretical financial incentive to do so? Potential explanations include the persistence of domestic agricultural subsidies that distort production decisions, cultural preferences for diverse local food production, and that diverse food production protects rural households in developing countries from food price shocks. Less specialized production patterns will make crop systems more resilient to zonal climatic and social perturbations, but this may come at the expense of global crop production efficiency, an important step in making the transition to a hotter and more

  11. Testing Associations of Plant Functional Diversity with Carbon and Nitrogen Storage along a Restoration Gradient of Sandy Grassland.

    Science.gov (United States)

    Zuo, Xiaoan; Zhou, Xin; Lv, Peng; Zhao, Xueyong; Zhang, Jing; Wang, Shaokun; Yue, Xiyuan

    2016-01-01

    The trait-based approach shows that ecosystem function is strongly affected by plant functional diversity as reflected by the traits of the most abundant species (community-weighted mean, CWM) and functional dispersion (FDis). Effects of CWM and FDis individually support the biomass ratio hypothesis and the niche complementarity hypothesis. However, there is little empirical evidence on the relative roles of CWM traits and FDis in explaining the carbon (C) and nitrogen (N) storage in grassland ecosystems. We measured plant functional traits in the 34 most abundant species across 24 sites along a restoration gradient of sandy grassland (mobile dune, semi-fixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China. Thereafter, we calculated the CWM traits, the functional divergence of each single trait (FDvar) and the trait dispersion of multiple traits (FDis). We also measured the C and N storage in plant, litter, root, and soil. Using a stepwise multiple regression analysis, we further assessed which of the functional diversity components best explained C and N storage in the sandy grassland restoration. We found consistent links between C or N storage and leaf traits related to plant resource use strategy. However, the CWM of plant height was retained as an important predictor of C and N storage in plant, litter, soil, and total ecosystem in the final multiple models. CWMs of specific leaf area and plant height best predicted soil C and N storage and total ecosystem N storage. FDis was one of good predictors of litter C and N storage as well as total ecosystem C storage. These results suggest that ecosystem C and N pools in the sandy grassland restoration are primarily associated with the traits of the most abundant species in communities, thereby supporting the biomass ratio hypothesis. The positive associations of FDis with C storage in litter and total ecosystem provide evidence to support the niche complementarity hypothesis. Both functional

  12. Testing associations of plant functional diversity with carbon and nitrogen storage along a restoration gradient of sandy grassland

    Directory of Open Access Journals (Sweden)

    Xiaoan eZuo

    2016-02-01

    Full Text Available The trait-based approach shows that ecosystem function is strongly affected by plant functional diversity as reflected by the traits of the most abundant species (community-weighted mean, CWM and functional dispersion (FDis. Effects of CWM and FDis individually support the biomass ratio hypothesis and the niche complementarity hypothesis. However, there is little empirical evidence on the relative roles of CWM traits and FDis in explaining the carbon (C and nitrogen (N storage in grassland ecosystems. We measured plant functional traits in the 34 most abundant species across 24 sites along a restoration gradient of sandy grassland (mobile dune, semi-fixed dune, fixed dune and grassland in Horqin Sand Land, northern China. Thereafter, we calculated the CWM traits, the functional divergence of each single trait (FDvar and the trait dispersion of multiple traits (FDis. We also measured the C and N storage in plant, litter, root and soil. Using a stepwise multiple regression analysis, we further assessed which of the functional diversity components best explained C and N storage in the sandy grassland restoration. We found consistent links between C or N storage and leaf traits related to plant resource use strategy. However, the CWM of plant height was retained as an important predictor of C and N storage in plant, litter, soil and total ecosystem in the final multiple models. CWMs of specific leaf area and plant height best predicted soil C and N storage and total ecosystem N storage. FDis was one of good predictors of litter C and N storage as well as total ecosystem C storage. These results suggest that ecosystem C and N pools in the sandy grassland restoration are primarily associated with the traits of the most abundant species in communities, thereby supporting the biomass ratio hypothesis. The positive associations of FDis with C storage in litter and total ecosystem provide evidence to support the niche complementarity hypothesis. Both

  13. Species Richness and Functional Trait Diversity for Plants in Southern California's Green Infrastructure along a Climate Gradient

    Science.gov (United States)

    Rochford, M. E.; Ibsen, P.; Jenerette, D.

    2016-12-01

    Green infrastructure (GI) is greenery planted to absorb rainwater into the earth as an alternative to grey infrastructure, like storm drains. Not only does GI prevent flooding, but it also performs a number of ecosystem services, including increasing biodiversity, because it allows water to cycle through the environment naturally. Increased biodiversity in plant communities is said to help purify the air and improve the health and resilience of the plants themselves. I want to investigate these claims about GI's benefits by studying types of GI with slightly different functions. This will answer the questions 1) Are different types of green infrastructure's plant communities equally biodiverse in terms of functional trait diversity and species richness? 2) How does functional trait diversity and species richness differ along a temperature gradient in Southern California? To compare biodiversity, I must survey four different types of GI, urban parks, riparian zones, detention basins, and bioswales, in three cities in distinct climate regions. Detention basins are reservoirs lined with vegetation that collect water until it is absorbed into the soil. Bioswales are vegetated gutters that filter out pollutants in storm water. Unlike retention basins, they also add aesthetic value to an area. Even though parks are mainly for recreation and beatification rather than storm water management, they have plenty of permeable surface to absorb storm water. The types of GI that have high levels of interaction with humans should also have higher levels of maintenance. The results should follow the homogenization hypothesis and demonstrate that, regardless of climate, species richness should not differ much between highly maintained areas, like parks, in different cities. Otherwise, in GI that is not as manicured, species richness should be significantly different between cities and the different types of GI. Because types of GI selected vary in expected levels of human

  14. Collembola in a plant diversity gradient: Interactions between the aboveground and belowground system

    OpenAIRE

    Sabais, Alexander Christian Wolf

    2012-01-01

    During the past few decades, there has been growing understanding that human well-being is fundamentally linked to the state of the environment. The rapid decline of global biodiversity and its consequences for ecosystem functioning therefore has become a focal point of scientific interest and prompted a multitude of biodiversity studies aiming to investigate the complex relationship between plant species richness and ecosystem functioning in terrestrial grassland ecosystems. However, the maj...

  15. Variation in tidal wetland plant diversity and composition within and among coastal estuaries: assessing the relative importance of environmental gradients

    Science.gov (United States)

    Question: Does wetland plant composition vary more by estuarine type (differentiated by the degree of riverine versus oceanic influence) or habitat type within estuaries (defined by US National Wetlands Inventory [NWI] marsh classes)? Location: Oregon estuaries: Netarts Bay, ...

  16. Evolution & Diversity in Plants.

    Science.gov (United States)

    Pearson, Lorentz C.

    1988-01-01

    Summarizes recent findings that help in understanding how evolution has brought about the diversity of plant life that presently exists. Discusses basic concepts of evolution, diversity and classification, the three-line hypothesis of plant evolution, the origin of fungi, and the geologic time table. Included are 31 references. (CW)

  17. A latitudinal phylogeographic diversity gradient in birds.

    Science.gov (United States)

    Smith, Brian Tilston; Seeholzer, Glenn F; Harvey, Michael G; Cuervo, Andrés M; Brumfield, Robb T

    2017-04-01

    High tropical species diversity is often attributed to evolutionary dynamics over long timescales. It is possible, however, that latitudinal variation in diversification begins when divergence occurs within species. Phylogeographic data capture this initial stage of diversification in which populations become geographically isolated and begin to differentiate genetically. There is limited understanding of the broader implications of intraspecific diversification because comparative analyses have focused on species inhabiting and evolving in restricted regions and environments. Here, we scale comparative phylogeography up to the hemisphere level and examine whether the processes driving latitudinal differences in species diversity are also evident within species. We collected genetic data for 210 New World bird species distributed across a broad latitudinal gradient and estimated a suite of metrics characterizing phylogeographic history. We found that lower latitude species had, on average, greater phylogeographic diversity than higher latitude species and that intraspecific diversity showed evidence of greater persistence in the tropics. Factors associated with species ecologies, life histories, and habitats explained little of the variation in phylogeographic structure across the latitudinal gradient. Our results suggest that the latitudinal gradient in species richness originates, at least partly, from population-level processes within species and are consistent with hypotheses implicating age and environmental stability in the formation of diversity gradients. Comparative phylogeographic analyses scaled up to large geographic regions and hundreds of species can show connections between population-level processes and broad-scale species-richness patterns.

  18. Patterns of fungal diversity and composition along a salinity gradient

    Science.gov (United States)

    Mohamed, Devon J; Martiny, Jennifer BH

    2011-01-01

    Estuarine salinity gradients are known to influence plant, bacterial and archaeal community structure. We sequenced 18S rRNA genes to investigate patterns in sediment fungal diversity (richness and evenness of taxa) and composition (taxonomic and phylogenetic) along an estuarine salinity gradient. We sampled three marshes—a salt, brackish and freshwater marsh—in Rhode Island. To compare the relative effect of the salinity gradient with that of plants, we sampled fungi in plots with Spartina patens and in plots from which plants were removed 2 years prior to sampling. The fungal sediment community was unique compared with previously sampled fungal communities; we detected more Ascomycota (78%), fewer Basidiomycota (6%) and more fungi from basal lineages (16%) (Chytridiomycota, Glomeromycota and four additional groups) than typically found in soil. Across marshes, fungal composition changed substantially, whereas fungal diversity differed only at the finest level of genetic resolution, and was highest in the intermediate, brackish marsh. In contrast, the presence of plants had a highly significant effect on fungal diversity at all levels of genetic resolution, but less of an effect on fungal composition. These results suggest that salinity (or other covarying parameters) selects for a distinctive fungal composition, and plants provide additional niches upon which taxa within these communities can specialize and coexist. Given the number of sequences from basal fungal lineages, the study also suggests that further sampling of estuarine sediments may help in understanding early fungal evolution. PMID:20882058

  19. How does pedogenesis drive plant diversity?

    Science.gov (United States)

    Laliberté, Etienne; Grace, James B.; Huston, Michael A.; Lambers, Hans; Teste, François P.; Turner, Benjamin L.; Wardle, David A.

    2013-01-01

    Some of the most species-rich plant communities occur on ancient, strongly weathered soils, whereas those on recently developed soils tend to be less diverse. Mechanisms underlying this well-known pattern, however, remain unresolved. Here, we present a conceptual model describing alternative mechanisms by which pedogenesis (the process of soil formation) might drive plant diversity. We suggest that long-term soil chronosequences offer great, yet largely untapped, potential as 'natural experiments' to determine edaphic controls over plant diversity. Finally, we discuss how our conceptual model can be evaluated quantitatively using structural equation modeling to advance multivariate theories about the determinants of local plant diversity. This should help us to understand broader-scale diversity patterns, such as the latitudinal gradient of plant diversity.

  20. Functional trait space and the latitudinal diversity gradient

    DEFF Research Database (Denmark)

    Lamanna, Christine; Blonder, Benjamin; Violle, Cyrille

    2014-01-01

    The processes causing the latitudinal gradient in species richness remain elusive. Ecological theories for the origin of biodiversity gradients, such as competitive exclusion, neutral dynamics, and environmental filtering, make predictions for how functional diversity should vary at the alpha (wi...

  1. Functional trait space and the latitudinal diversity gradient

    Science.gov (United States)

    Lamanna, Christine; Blonder, Benjamin; Violle, Cyrille; Kraft, Nathan J. B.; Sandel, Brody; Šímová, Irena; Donoghue, John C.; Svenning, Jens-Christian; McGill, Brian J.; Boyle, Brad; Buzzard, Vanessa; Dolins, Steven; Jørgensen, Peter M.; Marcuse-Kubitza, Aaron; Morueta-Holme, Naia; Peet, Robert K.; Piel, William H.; Regetz, James; Schildhauer, Mark; Spencer, Nick; Thiers, Barbara; Wiser, Susan K.; Enquist, Brian J.

    2014-01-01

    The processes causing the latitudinal gradient in species richness remain elusive. Ecological theories for the origin of biodiversity gradients, such as competitive exclusion, neutral dynamics, and environmental filtering, make predictions for how functional diversity should vary at the alpha (within local assemblages), beta (among assemblages), and gamma (regional pool) scales. We test these predictions by quantifying hypervolumes constructed from functional traits representing major axes of plant strategy variation (specific leaf area, plant height, and seed mass) in tree assemblages spanning the temperate and tropical New World. Alpha-scale trait volume decreases with absolute latitude and is often lower than sampling expectation, consistent with environmental filtering theory. Beta-scale overlap decays with geographic distance fastest in the temperate zone, again consistent with environmental filtering theory. In contrast, gamma-scale trait space shows a hump-shaped relationship with absolute latitude, consistent with no theory. Furthermore, the overall temperate trait hypervolume was larger than the overall tropical hypervolume, indicating that the temperate zone permits a wider range of trait combinations or that niche packing is stronger in the tropical zone. Although there are limitations in the data, our analyses suggest that multiple processes have shaped trait diversity in trees, reflecting no consistent support for any one theory. PMID:25225365

  2. Functional trait space and the latitudinal diversity gradient.

    Science.gov (United States)

    Lamanna, Christine; Blonder, Benjamin; Violle, Cyrille; Kraft, Nathan J B; Sandel, Brody; Šímová, Irena; Donoghue, John C; Svenning, Jens-Christian; McGill, Brian J; Boyle, Brad; Buzzard, Vanessa; Dolins, Steven; Jørgensen, Peter M; Marcuse-Kubitza, Aaron; Morueta-Holme, Naia; Peet, Robert K; Piel, William H; Regetz, James; Schildhauer, Mark; Spencer, Nick; Thiers, Barbara; Wiser, Susan K; Enquist, Brian J

    2014-09-23

    The processes causing the latitudinal gradient in species richness remain elusive. Ecological theories for the origin of biodiversity gradients, such as competitive exclusion, neutral dynamics, and environmental filtering, make predictions for how functional diversity should vary at the alpha (within local assemblages), beta (among assemblages), and gamma (regional pool) scales. We test these predictions by quantifying hypervolumes constructed from functional traits representing major axes of plant strategy variation (specific leaf area, plant height, and seed mass) in tree assemblages spanning the temperate and tropical New World. Alpha-scale trait volume decreases with absolute latitude and is often lower than sampling expectation, consistent with environmental filtering theory. Beta-scale overlap decays with geographic distance fastest in the temperate zone, again consistent with environmental filtering theory. In contrast, gamma-scale trait space shows a hump-shaped relationship with absolute latitude, consistent with no theory. Furthermore, the overall temperate trait hypervolume was larger than the overall tropical hypervolume, indicating that the temperate zone permits a wider range of trait combinations or that niche packing is stronger in the tropical zone. Although there are limitations in the data, our analyses suggest that multiple processes have shaped trait diversity in trees, reflecting no consistent support for any one theory.

  3. The drivers of plant diversity

    DEFF Research Database (Denmark)

    Jensen, Kristine Engemann

    In this thesis we use a “big data” approach to describe and explain large-scale patterns of plant diversity. The botanical data used for the six papers come from three different databases covering the New World, North America, and Europe respectively. The data on plant distributions were combined...... and beta diversity over time for woody forest communities in North America, using a 20 year forest plot dataset from the United States Department of Agriculture Forest Inventory and Analysis program. To assess functional diversity, we combined the plot data with data on four functional traits. Over time...... with environmental data on climate, soil, topography, and disturbance to identify the drivers of macroecological plant diversity patterns. Unless otherwise stated, the botanical data used in the papers come from the Botanical Information and Ecology Network. Paper I describes how we compiled a new plant growth form...

  4. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland

    OpenAIRE

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2015-01-01

    Abstract The trait‐based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gen...

  5. A Latitudinal Diversity Gradient in Terrestrial Bacteria of the Genus Streptomyces

    Directory of Open Access Journals (Sweden)

    Cheryl P. Andam

    2016-04-01

    Full Text Available We show that Streptomyces biogeography in soils across North America is influenced by the regional diversification of microorganisms due to dispersal limitation and genetic drift. Streptomyces spp. form desiccation-resistant spores, which can be dispersed on the wind, allowing for a strong test of whether dispersal limitation governs patterns of terrestrial microbial diversity. We employed an approach that has high sensitivity for determining the effects of genetic drift. Specifically, we examined the genetic diversity and phylogeography of physiologically similar Streptomyces strains isolated from geographically distributed yet ecologically similar habitats. We found that Streptomyces beta diversity scales with geographic distance and both beta diversity and phylogenetic diversity manifest in a latitudinal diversity gradient. This pattern of Streptomyces biogeography resembles patterns seen for diverse species of plants and animals, and we therefore evaluated these data in the context of ecological and evolutionary hypotheses proposed to explain latitudinal diversity gradients. The data are consistent with the hypothesis that niche conservatism limits dispersal, and historical patterns of glaciation have limited the time for speciation in higher-latitude sites. Most notably, higher-latitude sites have lower phylogenetic diversity, higher phylogenetic clustering, and evidence of range expansion from lower latitudes. In addition, patterns of beta diversity partition with respect to the glacial history of sites. Hence, the data support the hypothesis that extant patterns of Streptomyces biogeography have been driven by historical patterns of glaciation and are the result of demographic range expansion, dispersal limitation, and regional diversification due to drift.

  6. Diversity of Eastern North American ant communities along environmental gradients.

    Directory of Open Access Journals (Sweden)

    Israel Del Toro

    Full Text Available Studies of species diversity patterns across regional environmental gradients seldom consider the impact of habitat type on within-site (alpha and between-site (beta diversity. This study is designed to identify the influence of habitat type across geographic and environmental space, on local patterns of species richness and regional turnover patterns of ant diversity in the northeastern United States. Specifically, I aim to 1 compare local species richness in paired open and forested transects and identify the environmental variables that best correlate with richness; and 2 document patterns of beta diversity throughout the region in both open and forested habitat. I systematically sampled ants at 67 sites from May to August 2010, spanning 10 degrees of latitude, and 1000 meters of elevation. Patterns of alpha and beta diversity across the region and along environmental gradients differed between forested and open habitats. Local species richness was higher in the low elevation and warmest sites and was always higher in open habitat than in forest habitat transects. Richness decreased as temperature decreased or elevation increased. Forested transects show strong patterns of decreasing dissimilarity in species composition between sites along the temperature gradient but open habitat transects did not. Maximum temperature of the warmest month better predicted species richness than either latitude or elevation. I find that using environmental variables as key predictors of richness yields more biologically relevant results, and produces simpler macroecological models than commonly used models which use only latitude and elevation as predictors of richness and diversity patterns. This study contributes to the understanding of mechanisms that structure the communities of important terrestrial arthropods which are likely to be influenced by climatic change.

  7. Mutualistic rhizobia reduce plant diversity and alter community composition.

    Science.gov (United States)

    Keller, Kane R

    2014-12-01

    Mutualistic interactions can be just as important to community dynamics as antagonistic species interactions like competition and predation. Because of their large effects on both abiotic and biotic environmental variables, resource mutualisms, in particular, have the potential to influence plant communities. Moreover, the effects of resource mutualists such as nitrogen-fixing rhizobia on diversity and community composition may be more pronounced in nutrient-limited environments. I experimentally manipulated the presence of rhizobia across a nitrogen gradient in early assembling mesocosm communities with identical starting species composition to test how the classic mutualism between nitrogen-fixing rhizobia and their legume host influence diversity and community composition. After harvest, I assessed changes in α-diversity, community composition, β-diversity, and ecosystem properties such as inorganic nitrogen availability and productivity as a result of rhizobia and nitrogen availability. The presence of rhizobia decreased plant community diversity, increased community convergence (reduced β-diversity), altered plant community composition, and increased total community productivity. These community-level effects resulted from rhizobia increasing the competitive dominance of their legume host Chamaecrista fasciculata. Moreover, different non-leguminous species responded both negatively and positively to the presence of rhizobia, indicating that rhizobia are driving both inhibitory and potentially facilitative effects in communities. These findings expand our understanding of plant communities by incorporating the effects of positive symbiotic interactions on plant diversity and composition. In particular, rhizobia that specialize on dominant plants may serve as keystone mutualists in terrestrial plant communities, reducing diversity by more than 40%.

  8. Endophytic fungal diversity of Fragaria vesca, a crop wild relative of strawberry, along environmental gradients within a small geographical area.

    Science.gov (United States)

    Yokoya, Kazutomo; Postel, Sarah; Fang, Rui; Sarasan, Viswambharan

    2017-01-01

    Fungal endophytes are highly diverse ubiquitous asymptomatic microorganisms, some of which appear to be symbiotic. Depending on abiotic conditions and genotype of the plant, the diversity of endophytes may confer fitness benefits to plant communities. We studied a crop wild relative (CWR) of strawberry, along environmental gradients with a view to understand the cultivable root-derived endophytic fungi that can be evaluated for promoting growth and tolerating stress in selected plant groups. The main objectives were to understand whether: (a) suboptimal soil types are drivers for fungal distribution and diversity; (b) high pH and poor nutrient availability lead to fungal-plant associations that help deliver fitness benefits; and (c) novel fungi can be identified for their use in improving plant growth, and alleviate stress in diverse crops. The study revealed that habitats with high pH and low nutrient availability have higher fungal diversity, with more rare fungi isolated from locations with chalky soil. Plants from location G were the healthiest even though soil from this location was the poorest in nutrients. Study of environmental gradients, especially extreme habitat types, may help understand the root zone fungal diversity of different functional classes. Two small in vitro pilot studies conducted with two isolates showed that endophytic fungi from suboptimal habitats can promote plant growth and fitness benefits in selected plant groups. Targeting native plants and crop wild relatives for research offers opportunities to unearth diverse functional groups of root-derived endophytic fungi that are beneficial for crops.

  9. Diversity and composition of herbaceous angiosperms along gradients of elevation and forest-use intensity.

    Science.gov (United States)

    Gómez-Díaz, Jorge Antonio; Krömer, Thorsten; Kreft, Holger; Gerold, Gerhard; Carvajal-Hernández, César Isidro; Heitkamp, Felix

    2017-01-01

    Terrestrial herbs are important elements of tropical forests; however, there is a lack of research on their diversity patterns and how they respond to different intensities of forest-use. The aim of this study was to analyze the diversity of herbaceous angiosperms along gradients of elevation (50 m to 3500 m) and forest-use intensity on the eastern slopes of the Cofre de Perote, Veracruz, Mexico. We recorded the occurrence of all herbaceous angiosperm species within 120 plots of 20 m x 20 m each. The plots were located at eight study locations separated by ~500 m in elevation and within three different habitats that differ in forest-use intensity: old-growth, degraded, and secondary forest. We analyzed species richness and floristic composition of herb communities among different elevations and habitats. Of the 264 plant species recorded, 31 are endemic to Mexico. Both α- and γ-diversity display a hump-shaped relation to elevation peaking at 2500 m and 3000 m, respectively. The relative contribution of between-habitat β-diversity to γ-diversity also showed a unimodal hump whereas within-habitat β-diversity declined with elevation. Forest-use intensity did not affect α-diversity, but β-diversity was high between old-growth and secondary forests. Overall, γ-diversity peaked at 2500 m (72 species), driven mainly by high within- and among-habitat β-diversity. We infer that this belt is highly sensitive to anthropogenic disturbance and forest-use intensification. At 3100 m, high γ-diversity (50 species) was driven by high α- and within-habitat β-diversity. There, losing a specific forest area might be compensated if similar assemblages occur in nearby areas. The high β-diversity and endemism suggest that mixes of different habitats are needed to sustain high γ-richness of terrestrial herbs along this elevational gradient.

  10. Coastal microbial mat diversity along a natural salinity gradient.

    Directory of Open Access Journals (Sweden)

    Henk Bolhuis

    Full Text Available The North Sea coast of the Dutch barrier island of Schiermonnikoog is covered by microbial mats that initiate a succession of plant communities that eventually results in the development of a densely vegetated salt marsh. The North Sea beach has a natural elevation running from the low water mark to the dunes resulting in gradients of environmental factors perpendicular to the beach. These gradients are due to the input of seawater at the low water mark and of freshwater from upwelling groundwater at the dunes and rainfall. The result is a natural and dynamic salinity gradient depending on the tide, rainfall and wind. We studied the microbial community composition in thirty three samples taken every ten meters along this natural salinity gradient by using denaturing gradient gel electrophoresis (DGGE of rRNA gene fragments. We looked at representatives from each Domain of life (Bacteria, Archaea and Eukarya and with a particular emphasis on Cyanobacteria. Analysis of the DGGE fingerprints together with pigment composition revealed three distinct microbial mat communities, a marine community dominated by diatoms as primary producers, an intermediate brackish community dominated by Cyanobacteria as primary producers and a freshwater community with Cyanobacteria and freshwater green algae.

  11. Indirect drivers of plant diversity-productivity relationship in semiarid sandy grasslands

    Directory of Open Access Journals (Sweden)

    X. A. Zuo

    2012-04-01

    Full Text Available Although patterns between plant diversity and ecosystem productivity have been much studied, a consistent relationship has not yet emerged. Differing patterns between plant diversity and productivity have been observed in response to spatial variability of environmental factors and vegetation composition. In this study, we measured vegetation cover, plant diversity, productivity, soil properties and site characteristics along an environmental gradient (mobile dune, semi-fixed dune, fixed dune, dry meadow, wet meadow and flood plain grasslands of natural sandy grasslands in semiarid areas of northern China. We used multivariate analysis to examine the relationships between environmental factors, vegetation composition, plant diversity and productivity. We found a positive correlation between plant diversity and productivity. Vegetation composition aggregated by the ordination technique of non-metric multidimensional scaling had also a significantly positive correlation with plant diversity and productivity. Environmental gradients in relation to soil and topography affected the distribution patterns of vegetation composition, species diversity and productivity. However, environmental gradients were a better determinant of vegetation composition and productivity than of plant diversity. Structural equation modeling suggested that environmental factors determine vegetation composition, which in turn independently drives both plant diversity and productivity. Thus, the positive correlation between plant diversity and productivity is indirectly driven by vegetation composition, which is determined by environmental gradients in soil and topography.

  12. Coupling of soil prokaryotic diversity and plant diversity across latitudinal forest ecosystems

    Science.gov (United States)

    Wang, Jun-Tao; Zheng, Yuan-Ming; Hu, Hang-Wei; Li, Jing; Zhang, Li-Mei; Chen, Bao-Dong; Chen, Wei-Ping; He, Ji-Zheng

    2016-01-01

    The belowground soil prokaryotic community plays a cardinal role in sustaining the stability and functions of forest ecosystems. Yet, the nature of how soil prokaryotic diversity co-varies with aboveground plant diversity along a latitudinal gradient remains elusive. By establishing three hundred 400-m2 quadrats from tropical rainforest to boreal forest in a large-scale parallel study on both belowground soil prokaryote and aboveground tree and herb communities, we found that soil prokaryotic diversity couples with the diversity of herbs rather than trees. The diversity of prokaryotes and herbs responds similarly to environmental factors along the latitudinal gradient. These findings revealed that herbs provide a good predictor of belowground biodiversity in forest ecosystems, and provide new perspective on the aboveground and belowground interactions in forest ecosystems.

  13. Limiting similarity and functional diversity along environmental gradients

    Science.gov (United States)

    Schwilk, D.W.; Ackerly, D.D.

    2005-01-01

    Recent developments in community models emphasize the importance of incorporating stochastic processes (e.g. ecological drift) in models of niche-structured community assembly. We constructed a finite, spatially explicit, lottery model to simulate the distribution of species in a one-dimensional landscape with an underlying gradient in environmental conditions. Our framework combines the potential for ecological drift with environmentally-mediated competition for space in a heterogeneous environment. We examined the influence of niche breadth, dispersal distances, community size (total number of individuals) and the breadth of the environmental gradient on levels of species and functional trait diversity (i.e. differences in niche optima). Three novel results emerge from this model: (1) niche differences between adjacent species (e.g. limiting similarity) increase in smaller communities, because of the interaction of competitive effects and finite population sizes; (2) immigration from a regional species pool, stochasticity and niche-assembly generate a bimodal distribution of species residence times ('transient' and 'resident') under a heterogeneous environment; and (3) the magnitude of environmental heterogeneity has a U-shaped effect on diversity, because of shifts in species richness of resident vs. transient species. These predictions illustrate the potential importance of stochastic (although not necessarily neutral) processes in community assembly. ??2005 Blackwell Publishing Ltd/CNRS.

  14. plant diversity, vegetation structure and relationship between plant ...

    African Journals Online (AJOL)

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    analyses of five Afromontane forests altogether revealed 118 families and 653 vascular plant species; ... structure in the moist evergreen Afromontane forest ..... gradient of complex environmental factors. The .... other tropical montane forests.

  15. Intraspecific leaf trait variability along a boreal-to-tropical community diversity gradient

    Science.gov (United States)

    Bastias, Cristina C.; Fortunel, Claire; Valladares, Fernando; Baraloto, Christopher; Benavides, Raquel; Cornwell, William; Markesteijn, Lars; de Oliveira, Alexandre A.; Sansevero, Jeronimo B. B.; Vaz, Marcel C.; Kraft, Nathan J. B.

    2017-01-01

    Disentangling the mechanisms that shape community assembly across diversity gradients is a central matter in ecology. While many studies have explored community assembly through species average trait values, there is a growing understanding that intraspecific trait variation (ITV) can also play a critical role in species coexistence. Classic biodiversity theory hypothesizes that higher diversity at species-rich sites can arise from narrower niches relative to species-poor sites, which would be reflected in reduced ITV as species richness increases. To explore how ITV in woody plant communities changes with species richness, we compiled leaf trait data (leaf size and specific leaf area) in a total of 521 woody plant species from 21 forest communities that differed dramatically in species richness, ranging from boreal to tropical rainforests. At each forest, we assessed ITV as an estimate of species niche breadth and we quantified the degree of trait overlap among co-occurring species as a measure of species functional similarity. We found ITV was relatively invariant across the species richness gradient. In addition, we found that species functional similarity increased with diversity. Contrary to the expectation from classic biodiversity theory, our results rather suggest that neutral processes or equalizing mechanisms can be acting as potential drivers shaping community assembly in hyperdiverse forests. PMID:28241033

  16. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland.

    Science.gov (United States)

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2016-01-01

    The trait-based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gene sequencing. We also examined associations of soil fungal diversity with plant functional diversity reflected by the dominant species' traits in community (community-weighted mean, CWM) and the dispersion of functional trait values (FD is). We further used the structure equation model (SEM) to evaluate how plant richness, biomass, functional diversity, and soil properties affect soil fungal diversity in sandy grassland restoration. Soil fungal richness in mobile dune and semifixed dune was markedly lower than those of fixed dune and grassland (P functional diversity explained nearly 70% variances of soil fungal richness. Strong association of soil fungal richness with the dominant species in the community supported the mass ratio hypothesis. Our results clearly highlight the role of plant functional diversity in enhancing associations of soil fungal diversity with community structure and soil properties in sandy grassland ecosystems.

  17. Latitudinal diversity gradients in Mesozoic non-marine turtles

    Science.gov (United States)

    Nicholson, David B.; Holroyd, Patricia A.; Valdes, Paul; Barrett, Paul M.

    2016-11-01

    The latitudinal biodiversity gradient (LBG)-the pattern of increasing taxonomic richness with decreasing latitude-is prevalent in the structure of the modern biota. However, some freshwater taxa show peak richness at mid-latitudes; for example, extant Testudines (turtles, terrapins and tortoises) exhibit their greatest diversity at 25° N, a pattern sometimes attributed to recent bursts of climatically mediated species diversification. Here, we test whether this pattern also characterizes the Mesozoic distribution of turtles, to determine whether it was established during either their initial diversification or as a more modern phenomenon. Using global occurrence data for non-marine testudinate genera, we find that subsampled richness peaks at palaeolatitudes of 15-30° N in the Jurassic, 30-45° N through the Cretaceous to the Campanian, and from 30° to 60° N in the Maastrichtian. The absence of a significant diversity peak in southern latitudes is consistent with results from climatic models and turtle niche modelling that demonstrate a dearth of suitable turtle habitat in Gondwana during the Jurassic and Late Cretaceous. Our analyses confirm that the modern testudinate LBG has a deep-time origin and further demonstrate that LBGs are not always expressed as a smooth, equator-to-pole distribution.

  18. Endophytic fungal diversity of Fragaria vesca, a crop wild relative of strawberry, along environmental gradients within a small geographical area

    Science.gov (United States)

    Yokoya, Kazutomo; Postel, Sarah; Fang, Rui

    2017-01-01

    Background Fungal endophytes are highly diverse ubiquitous asymptomatic microorganisms, some of which appear to be symbiotic. Depending on abiotic conditions and genotype of the plant, the diversity of endophytes may confer fitness benefits to plant communities. Methods We studied a crop wild relative (CWR) of strawberry, along environmental gradients with a view to understand the cultivable root-derived endophytic fungi that can be evaluated for promoting growth and tolerating stress in selected plant groups. The main objectives were to understand whether: (a) suboptimal soil types are drivers for fungal distribution and diversity; (b) high pH and poor nutrient availability lead to fungal-plant associations that help deliver fitness benefits; and (c) novel fungi can be identified for their use in improving plant growth, and alleviate stress in diverse crops. Results The study revealed that habitats with high pH and low nutrient availability have higher fungal diversity, with more rare fungi isolated from locations with chalky soil. Plants from location G were the healthiest even though soil from this location was the poorest in nutrients. Study of environmental gradients, especially extreme habitat types, may help understand the root zone fungal diversity of different functional classes. Two small in vitro pilot studies conducted with two isolates showed that endophytic fungi from suboptimal habitats can promote plant growth and fitness benefits in selected plant groups. Discussion Targeting native plants and crop wild relatives for research offers opportunities to unearth diverse functional groups of root-derived endophytic fungi that are beneficial for crops. PMID:28168102

  19. The Brazilian freshwater wetscape: Changes in tree community diversity and composition on climatic and geographic gradients

    Science.gov (United States)

    Wittmann, Florian; Marques, Márcia C. M.; Damasceno Júnior, Geraldo; Budke, Jean Carlos; Piedade, Maria T. F.; de Oliveira Wittmann, Astrid; Montero, Juan Carlos; de Assis, Rafael L.; Targhetta, Natália; Parolin, Pia; Junk, Wolfgang J.

    2017-01-01

    Wetlands harbor an important compliment of regional plant diversity, but in many regions data on wetland diversity and composition is still lacking, thus hindering our understanding of the processes that control it. While patterns of broad-scale terrestrial diversity and composition typically correlate with contemporary climate it is not clear to what extent patterns in wetlands are complimentary, or conflicting. To elucidate this, we consolidate data from wetland forest inventories in Brazil and examine patterns of diversity and composition along temperature and rainfall gradients spanning five biomes. We collated 196 floristic inventories covering an area >220 ha and including >260,000 woody individuals. We detected a total of 2,453 tree species, with the Amazon alone accounting for nearly half. Compositional patterns indicated differences in freshwater wetland floras among Brazilian biomes, although biomes with drier, more seasonal climates tended to have a larger proportion of more widely distributed species. Maximal alpha diversity increased with annual temperature, rainfall, and decreasing seasonality, patterns broadly consistent with upland vegetation communities. However, alpha diversity-climate relationships were only revealed at higher diversity values associated with the uppermost quantiles, and in most sites diversity varied irrespective of climate. Likewise, mean biome-level differences in alpha-diversity were unexpectedly modest, even in comparisons of savanna-area wetlands to those of nearby forested regions. We describe attenuated wetland climate-diversity relationships as a shifting balance of local and regional effects on species recruitment. Locally, excessive waterlogging strongly filters species able to colonize from regional pools. On the other hand, increased water availability can accommodate a rich community of drought-sensitive immigrant species that are able to track buffered wetland microclimates. We argue that environmental conditions

  20. Root exudate cocktails: the link between plant diversity and soil microorganisms?

    Science.gov (United States)

    Steinauer, Katja; Chatzinotas, Antonis; Eisenhauer, Nico

    2016-10-01

    Higher plant diversity is often associated with higher soil microbial biomass and diversity, which is assumed to be partly due to elevated root exudate diversity. However, there is little experimental evidence that diversity of root exudates shapes soil microbial communities. We tested whether higher root exudate diversity enhances soil microbial biomass and diversity in a plant diversity gradient, thereby negating significant plant diversity effects on soil microbial properties. We set up plant monocultures and two- and three-species mixtures in microcosms using functionally dissimilar plants and soil of a grassland biodiversity experiment in Germany. Artificial exudate cocktails were added by combining the most common sugars, organic acids, and amino acids found in root exudates. We applied four different exudate cocktails: two exudate diversity levels (low- and high-diversity) and two nutrient-enriched levels (carbon- and nitrogen-enriched), and a control with water only. Soil microorganisms were more carbon- than nitrogen-limited. Cultivation-independent fingerprinting analysis revealed significantly different soil microbial communities among exudate diversity treatments. Most notably and according to our hypothesis, adding diverse exudate cocktails negated the significant plant diversity effect on soil microbial properties. Our findings provide the first experimental evidence that root exudate diversity is a crucial link between plant diversity and soil microorganisms.

  1. Mycorrhizal fungal identity and diversity relaxes plant-plant competition.

    Science.gov (United States)

    Wagg, Cameron; Jansa, Jan; Stadler, Marina; Schmid, Bernhard; van der Heijden, Marcel G A

    2011-06-01

    There is a great interest in ecology in understanding the role of soil microbial diversity for plant productivity and coexistence. Recent research has shown increases in species richness of mutualistic soil fungi, the arbuscular mycorrhizal fungi (AMF), to be related to increases in aboveground productivity of plant communities. However, the impact of AMF richness on plant-plant interactions has not been determined. Moreover, it is unknown whether species-rich AMF communities can act as insurance to maintain productivity in a fluctuating environment (e.g., upon changing soil conditions). We tested the impact of four different AMF taxa and of AMF diversity (no AMF, single AMF taxa, and all four together) on competitive interactions between the legume Trifolium pratense and the grass Lolium multiflorum grown under two different soil conditions of low and high sand content. We hypothesized that more diverse mutualistic interactions (e.g., when four AMF taxa are present) can ease competitive effects between plants, increase plant growth, and maintain plant productivity across different soil environments. We used quantitative PCR to verify that AMF taxa inoculated at the beginning of the experiment were still present at the end. The presence of AMF reduced the competitive inequality between the two plant species by reducing the growth suppression of the legume by the grass. High AMF richness enhanced the combined biomass production of the two plant species and the yield of the legume, particularly in the more productive soil with low sand content. In the less productive (high sand content) soil, the single most effective AMF had an equally beneficial effect on plant productivity as the mixture of four AMF. Since contributions of single AMF to plant productivity varied between both soils, higher AMF richness would be required to maintain plant productivity in heterogeneous environments. Overall this work shows that AMF diversity promotes plant productivity and that AMF

  2. The mossy north: an inverse latitudinal diversity gradient in European bryophytes

    Science.gov (United States)

    Mateo, Rubén G.; Broennimann, Olivier; Normand, Signe; Petitpierre, Blaise; Araújo, Miguel B.; Svenning, Jens-C.; Baselga, Andrés; Fernández-González, Federico; Gómez-Rubio, Virgilio; Muñoz, Jesús; Suarez, Guillermo M.; Luoto, Miska; Guisan, Antoine; Vanderpoorten, Alain

    2016-05-01

    It remains hotly debated whether latitudinal diversity gradients are common across taxonomic groups and whether a single mechanism can explain such gradients. Investigating species richness (SR) patterns of European land plants, we determine whether SR increases with decreasing latitude, as predicted by theory, and whether the assembly mechanisms differ among taxonomic groups. SR increases towards the south in spermatophytes, but towards the north in ferns and bryophytes. SR patterns in spermatophytes are consistent with their patterns of beta diversity, with high levels of nestedness and turnover in the north and in the south, respectively, indicating species exclusion towards the north and increased opportunities for speciation in the south. Liverworts exhibit the highest levels of nestedness, suggesting that they represent the most sensitive group to the impact of past climate change. Nevertheless, although the extent of liverwort species turnover in the south is substantially and significantly lower than in spermatophytes, liverworts share with the latter a higher nestedness in the north and a higher turn-over in the south, in contrast to mosses and ferns. The extent to which the similarity in the patterns displayed by spermatophytes and liverworts reflects a similar assembly mechanism remains, however, to be demonstrated.

  3. Plant Sterols: Diversity, Biosynthesis, and Physiological Functions.

    Science.gov (United States)

    Valitova, J N; Sulkarnayeva, A G; Minibayeva, F V

    2016-08-01

    Sterols, which are isoprenoid derivatives, are structural components of biological membranes. Special attention is now being given not only to their structure and function, but also to their regulatory roles in plants. Plant sterols have diverse composition; they exist as free sterols, sterol esters with higher fatty acids, sterol glycosides, and acylsterol glycosides, which are absent in animal cells. This diversity of types of phytosterols determines a wide spectrum of functions they play in plant life. Sterols are precursors of a group of plant hormones, the brassinosteroids, which regulate plant growth and development. Furthermore, sterols participate in transmembrane signal transduction by forming lipid microdomains. The predominant sterols in plants are β-sitosterol, campesterol, and stigmasterol. These sterols differ in the presence of a methyl or an ethyl group in the side chain at the 24th carbon atom and are named methylsterols or ethylsterols, respectively. The balance between 24-methylsterols and 24-ethylsterols is specific for individual plant species. The present review focuses on the key stages of plant sterol biosynthesis that determine the ratios between the different types of sterols, and the crosstalk between the sterol and sphingolipid pathways. The main enzymes involved in plant sterol biosynthesis are 3-hydroxy-3-methylglutaryl-CoA reductase, C24-sterol methyltransferase, and C22-sterol desaturase. These enzymes are responsible for maintaining the optimal balance between sterols. Regulation of the ratios between the different types of sterols and sterols/sphingolipids can be of crucial importance in the responses of plants to stresses.

  4. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake.

    Science.gov (United States)

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Zhang, Feifan; Huang, Hai

    2017-01-20

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index), varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE) also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity), i.e., a positive diversity-stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation) of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems.

  5. The evolution of African plant diversity

    OpenAIRE

    Hans Peter Linder

    2014-01-01

    Sub-Saharan Africa includes some 45,000 plant species. The spatial patterns of this diversity have been well explored. We can group the species into a set of biogeographical regions (largely co-incident with regions defined for terrestrial vertebrate groups). Furthermore, we know that the diversity is unevenly distributed, with southern Africa (especially the south-western tip) disproportionally species rich, while the West African interior is disproportionally species poor. However, the ...

  6. Higher speciation and lower extinction rates influence mammal diversity gradients in Asia.

    Science.gov (United States)

    Tamma, Krishnapriya; Ramakrishnan, Uma

    2015-02-04

    Little is known about the patterns and correlates of mammal diversity gradients in Asia. In this study, we examine patterns of species distributions and phylogenetic diversity in Asia and investigate if the observed diversity patterns are associated with differences in diversification rates between the tropical and non-tropical regions. We used species distribution maps and phylogenetic trees to generate species and phylogenetic diversity measures for 1° × 1° cells across mainland Asia. We constructed lineage-through-time plots and estimated diversification shift-times to examine the temporal patterns of diversifications across orders. Finally, we tested if the observed gradients in Asia could be associated with geographical differences in diversification rates across the tropical and non-tropical biomes. We estimated speciation, extinction and dispersal rates across these two regions for mammals, both globally and for Asian mammals. Our results demonstrate strong latitudinal and longitudinal gradients of species and phylogenetic diversity with Southeast Asia and the Himalayas showing highest diversity. Importantly, our results demonstrate that differences in diversification (speciation, extinction and dispersal) rates between the tropical and the non-tropical biomes influence the observed diversity gradients globally and in Asia. For the first time, we demonstrate that Asian tropics act as both cradles and museums of mammalian diversity. Temporal and spatial variation in diversification rates across different lineages of mammals is an important correlate of species diversity gradients observed in Asia.

  7. Disentangling the drivers of ß diversity along latitudinal and elevational gradients

    DEFF Research Database (Denmark)

    Kraft, Nathan J. B.; Comita, Liza S.; Chase, Jonathan M.;

    2011-01-01

    Understanding spatial variation in biodiversity along environmental gradients is a central theme in ecology. Differences in species compositional turnover among sites (ß diversity) occurring along gradients are often used to infer variation in the processes structuring communities. Here, we show...... that sampling alone predicts changes in ß diversity caused simply by changes in the sizes of species pools. For example, forest inventories sampled along latitudinal and elevational gradients show the well-documented pattern that ß diversity is higher in the tropics and at low elevations. However, after...... correcting for variation in pooled species richness (¿ diversity), these differences in ß diversity disappear. Therefore, there is no need to invoke differences in the mechanisms of community assembly in temperate versus tropical systems to explain these global-scale patterns of ß diversity....

  8. Distribution of Vascular Plant Species Richness Along an Elevational Gradient in the Dongling Mountains, Beijing, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Quantifying spatial patterns of species richness and determining the processes that give rise to these patterns are core problems In blodlveralty theory. The aim of the present paper was to more accurately detect patterns of vascular species richness at different scales along altitudinal gradients in order to further our understanding of biodlverslty patterns and to facilitate studies on relationships between biodiversity and environmental factors. Species richness patterns of total vascular plants species, including trees, shrubs, and herbs, were measured along an altitudinal gradient on one transect on a shady slope in the Dongling Mountains, near Beijing,China. Direct gradient analysis, regression analysis, and geostatistics were applied to describe the spatial patterns of species richness. We found that total vascular species richness did not exhibit a linear pattern of change with altitude, although species groups with different ecological features showed strong elevational patterns different from total species richness. In addition to total vascular plants, analysis of trees, shrubs, and herbs demonstrated remarkable hierarchical structures of species richness with altitude (i.e. patchy structures at small scales and gradients at large scales). Species richness for trees and shrubs had similar spatial characteristics at different scales, but differed from herbs. These results indicated that species groups with similar ecological features exhibit similar biodlveraity patterns with altitude, and studies of biodiversity based on species groups with similar ecological properties or life forms would advance our understanding of variations in species diversity. Furthermore, the gradients or trends appeared to be due mainly to local variations in species richness means with altitude. We also found that the range of spatial scale dependencies of species richness for total vascular plants, trees, shrubs, and herbs was relatively large. Thus, to detect the

  9. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake

    Science.gov (United States)

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Zhang, Feifan; Huang, Hai

    2017-01-01

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index), varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE) also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity), i.e., a positive diversity–stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation) of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems. PMID:28117684

  10. Human Impacts Flatten Rainforest-Savanna Gradient and Reduce Adaptive Diversity in a Rainforest Bird

    OpenAIRE

    Freedman, Adam H.; Wolfgang Buermann; Mitchard, Edward T A; DeFries, Ruth S.; Smith, Thomas B

    2010-01-01

    Ecological gradients have long been recognized as important regions for diversification and speciation. However, little attention has been paid to the evolutionary consequences or conservation implications of human activities that fundamentally change the environmental features of such gradients. Here we show that recent deforestation in West Africa has homogenized the rainforest-savanna gradient, causing a loss of adaptive phenotypic diversity in a common rainforest bird, the little greenbul...

  11. A PCR-denaturing gradient gel electrophoresis approach to assess Fusarium diversity in asparagus.

    Science.gov (United States)

    Yergeau, E; Filion, M; Vujanovic, V; St-Arnaud, M

    2005-02-01

    In North America, asparagus (Asparagus officinalis) production suffers from a crown and root rot disease mainly caused by Fusarium oxysporum f. sp. asparagi and F. proliferatum. Many other Fusarium species are also found in asparagus fields, whereas accurate detection and identification of these organisms, especially when processing numerous samples, is usually difficult and time consuming. In this study, a PCR-denaturing gradient gel electrophoresis (DGGE) method was developed to assess Fusarium species diversity in asparagus plant samples. Fusarium-specific PCR primers targeting a partial region of the translation elongation factor-1 alpha (EF-1 alpha) gene were designed, and their specificity was tested against genomic DNA extracted from a large collection of closely and distantly related organisms isolated from multiple environments. Amplicons of 450 bp were obtained from all Fusarium isolates, while no PCR product was obtained from non-Fusarium organisms. The ability of DGGE to discriminate between Fusarium taxa was tested over 19 different Fusarium species represented by 39 isolates, including most species previously reported from asparagus fields worldwide. The technique was effective to visually discriminate between the majority of Fusarium species and/or isolates tested in pure culture, while a further sequencing step permitted to distinguish between the few species showing similar migration patterns. Total genomic DNA was extracted from field-grown asparagus plants naturally infested with different Fusarium species, submitted to PCR amplification, DGGE analysis and sequencing. The two to four bands observed for each plant sample were all affiliated with F. oxysporum, F. proliferatum or F. solani, clearly supporting the reliability, sensitivity and specificity of this approach for the study of Fusarium diversity from asparagus plants samples.

  12. Plant Size and Competitive Dynamics along Nutrient Gradients.

    Science.gov (United States)

    Goldberg, Deborah E; Martina, Jason P; Elgersma, Kenneth J; Currie, William S

    2017-08-01

    Resource competition theory in plants has focused largely on resource acquisition traits that are independent of size, such as traits of individual leaves or roots or proportional allocation to different functions. However, plants also differ in maximum potential size, which could outweigh differences in module-level traits. We used a community ecosystem model called mondrian to investigate whether larger size inevitably increases competitive ability and how size interacts with nitrogen supply. Contrary to the conventional wisdom that bigger is better, we found that invader success and competitive ability are unimodal functions of maximum potential size, such that plants that are too large (or too small) are disproportionately suppressed by competition. Optimal size increases with nitrogen supply, even when plants compete for nitrogen only in a size-symmetric manner, although adding size-asymmetric competition for light does substantially increase the advantage of larger size at high nitrogen. These complex interactions of plant size and nitrogen supply lead to strong nonlinearities such that small differences in nitrogen can result in large differences in plant invasion success and the influence of competition along productivity gradients.

  13. Altitudinal Pattern of Plant Species Diversity in Shennongjia Mountains, Central China

    Institute of Scientific and Technical Information of China (English)

    Chang-Ming ZHAO; Wei-Lie CHEN; Zi-Qiang TIAN; Zong-Qiang XIE

    2005-01-01

    One hundred and sixty plots, approximately every 100 m above sea level (a.s.l.) along an altitudinal gradient from 470 to 3 080 m a.s.l, at the southern and northern watershed of Mt. Shennongjia,China, were examined to determine the altitudinal pattern of plant species diversity. Mt. Shennongjia was found to have high plant species diversity, with 3 479 higher plants recorded. Partial correlation analysis and detrended canonical correspondence analysis (DCCA) based on plant species diversity revealed that altitude was the main factor affecting the spatial pattern of plant species diversity on Mt. Shennongjia and that canopy coverage of the arbor layer also had a considerable effect on plant species diversity. The DCCA based on species data of importance value further revealed that altitude gradient was the primary factor shaping the spatial pattern of plant species. In addition, the rule of the "mid-altitude bulge" was supported on Mt. Shennongjia. Plant species diversity was closely related to vegetation type and the transition zone usually had a higher diversity. Higher plant species diversity appeared in the mixed evergreen and deciduous broadleaved forest zone (900-1 500 m a.s.l.) and its transition down to evergreen broadleaved forest zone or up to deciduous broadleaved forest zone. The largest plant species diversity in whole communities on Mt. Shennongjia lay at approximately 1 200 m a.s.l. Greatest tree diversity, shrub diversity, and grass diversity was found at approximately 1 500, 1 100, and 1 200 m a.s.l., respectively. The southern watershed showed higher plant species diversity than the northern watershed, with maximum plant species diversity at a higher altitude in the southern watershed than the northern watershed. These results indicate that Mt.Shennongjia shows characteristics of a transition region. The relationship between the altitudinal pattern of plant species diversity and the vegetation type in eastern China are also discussed and a

  14. Dung Beetles along a Tropical Altitudinal Gradient: Environmental Filtering on Taxonomic and Functional Diversity

    Science.gov (United States)

    Nunes, Cássio Alencar; Braga, Rodrigo Fagundes; Figueira, José Eugênio Cortes; Neves, Frederico de Siqueira; Fernandes, G. Wilson

    2016-01-01

    Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will

  15. Dung Beetles along a Tropical Altitudinal Gradient: Environmental Filtering on Taxonomic and Functional Diversity.

    Science.gov (United States)

    Nunes, Cássio Alencar; Braga, Rodrigo Fagundes; Figueira, José Eugênio Cortes; Neves, Frederico de Siqueira; Fernandes, G Wilson

    2016-01-01

    Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will

  16. Phylogeny, niche conservatism and the latitudinal diversity gradient in mammals

    Science.gov (United States)

    Buckley, Lauren B.; Davies, T. Jonathan; Ackerly, David D.; Kraft, Nathan J. B.; Harrison, Susan P.; Anacker, Brian L.; Cornell, Howard V.; Damschen, Ellen I.; Grytnes, John-Avid; Hawkins, Bradford A.; McCain, Christy M.; Stephens, Patrick R.; Wiens, John J.

    2010-01-01

    Biologists have long searched for mechanisms responsible for the increase in species richness with decreasing latitude. The strong correlation between species richness and climate is frequently interpreted as reflecting a causal link via processes linked to energy or evolutionary rates. Here, we investigate how the aggregation of clades, as dictated by phylogeny, can give rise to significant climate–richness gradients without gradients in diversification or environmental carrying capacity. The relationship between climate and species richness varies considerably between clades, regions and time periods in a global-scale phylogenetically informed analysis of all terrestrial mammal species. Many young clades show negative richness–temperature slopes (more species at cooler temperatures), with the ages of these clades coinciding with the expansion of temperate climate zones in the late Eocene. In carnivores, we find steeply positive richness–temperature slopes in clades with restricted distributions and tropical origins (e.g. cat clade), whereas widespread, temperate clades exhibit shallow, negative slopes (e.g. dog–bear clade). We show that the slope of the global climate–richness gradient in mammals is driven by aggregating Chiroptera (bats) with their Eutherian sister group. Our findings indicate that the evolutionary history should be accounted for as part of any search for causal links between environment and species richness. PMID:20335205

  17. Response to Comments on "Disentangling the Drivers of β Diversity Along Latitudinal and Elevational Gradients"

    DEFF Research Database (Denmark)

    Kraft, Nathan J.B.; Sanders, Nathan J.; Stegen, James C.;

    2012-01-01

    Qian et al. and Tuomisto and Ruokolainen critique our analyses of elevational and latitudinal variation in tree diversity. We address their points by reanalyzing different subsets of our data and by clarifying certain misconceptions, and reiterate that gradients in β diversity can be explained in...

  18. Diverse Roles of Strigolactones in Plant Development

    Institute of Scientific and Technical Information of China (English)

    Philip B. Brewer; Hinanit Koltai; Christine A. Beveridge

    2013-01-01

    With the discovery of strigolactones as root exudate signals that trigger parasitic weed seed germination,and then as a branching inhibitor and plant hormone,the next phase of strigolactone research has quickly revealed this hormone class as a major player in optimizing plant growth and development.From the early stages of plant evolution,it seems that strigolactones were involved in enabling plants to modify growth in order to gain advantage in competition with neighboring organisms for limited resources.For example,a moss plant can alter its growth in response to strigolactones emanating from a neighbor.Within a higher plant,strigolactones appear to be involved in controlling the balance of resource distribution via strategic modification of growth and development.Most notably,higher plants that encounter phosphate deficiency increase strigolactone production,which changes root growth and promotes fungal symbiosis to enhance phosphate intake.The shoot also changes by channeling resources away from unessential leaves and branches and into the main stem and root system.This hormonal response is a key adaption that radically alters whole-plant architecture in order to optimize growth and development under diverse environmental conditions.

  19. Biotic and abiotic properties mediating plant diversity effects on soil microbial communities in an experimental grassland.

    Directory of Open Access Journals (Sweden)

    Markus Lange

    Full Text Available Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs. In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities.

  20. Biotic and abiotic properties mediating plant diversity effects on soil microbial communities in an experimental grassland.

    Science.gov (United States)

    Lange, Markus; Habekost, Maike; Eisenhauer, Nico; Roscher, Christiane; Bessler, Holger; Engels, Christof; Oelmann, Yvonne; Scheu, Stefan; Wilcke, Wolfgang; Schulze, Ernst-Detlef; Gleixner, Gerd

    2014-01-01

    Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness) and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA) analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs). In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities.

  1. Why do high-redshift galaxies show diverse gas-phase metallicity gradients?

    CERN Document Server

    Ma, Xiangcheng; Feldmann, Robert; Torrey, Paul; Faucher-Giguere, Claude-Andre; Keres, Dusan

    2016-01-01

    Recent spatially resolved observations of galaxies at z=0.6-3 reveal that high-redshift galaxies show complex kinematics and a broad distribution of gas-phase metallicity gradients. To understand these results, we use a suite of high-resolution cosmological zoom-in simulations from the Feedback in Realistic Environments (FIRE) project, which include physically motivated models of the multi-phase ISM, star formation, and stellar feedback. Our simulations reproduce the observed diversity of kinematic properties and metallicity gradients, broadly consistent with observations at z=0-3. Strong negative metallicity gradients only appear in galaxies with a rotating disk, but not all rotationally supported galaxies have significant gradients. Strongly perturbed galaxies with little rotation always have flat gradients. The kinematic properties and metallicity gradient of a high-redshift galaxy can vary significantly on short time-scales, associated with starburst episodes. Feedback from a starburst can destroy the gas...

  2. Coastal Microbial Mat Diversity along a Natural Salinity Gradient

    NARCIS (Netherlands)

    Bolhuis, H.; Fillinger, L.; Stal, L.J.

    2013-01-01

    The North Sea coast of the Dutch barrier island of Schiermonnikoog is covered by microbial mats that initiate a succession of plant communities that eventually results in the development of a densely vegetated salt marsh. The North Sea beach has a natural elevation running from the low water mark to

  3. Mean annual precipitation explains spatiotemporal patterns of Cenozoic mammal beta diversity and latitudinal diversity gradients in North America.

    Directory of Open Access Journals (Sweden)

    Danielle Fraser

    Full Text Available Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i a paleontological dataset (2077 localities with 2493 taxon occurrences spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present, and (ii climate space model predictions for 744 extant mammals under eight scenarios of future climate change. Spatial variation in fossil mammal community structure (β diversity is highest at intermediate values of continental mean annual precipitation (MAP estimated from paleosols (∼ 450 mm/year and declines under both wetter and drier conditions, reflecting diversity patterns of modern mammals. Latitudinal gradients in community change (latitudinal turnover gradients, aka LTGs increase in strength through the Cenozoic, but also show a cyclical pattern that is significantly explained by MAP. In general, LTGs are weakest when continental MAP is highest, similar to modern tropical ecosystems in which latitudinal diversity gradients are weak or undetectable. Projections under modeled climate change show no substantial change in β diversity or LTG strength for North American mammals. Our results suggest that similar climate-mediated mechanisms might drive spatial and temporal patterns of community composition in both fossil and extant mammals. We also provide empirical evidence that the ecological processes on which climate space models are based are insufficient for accurately forecasting long-term mammalian response to anthropogenic climate change and inclusion of historical parameters may be essential.

  4. Mean annual precipitation explains spatiotemporal patterns of Cenozoic mammal beta diversity and latitudinal diversity gradients in North America.

    Science.gov (United States)

    Fraser, Danielle; Hassall, Christopher; Gorelick, Root; Rybczynski, Natalia

    2014-01-01

    Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i) a paleontological dataset (2077 localities with 2493 taxon occurrences) spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma--present), and (ii) climate space model predictions for 744 extant mammals under eight scenarios of future climate change. Spatial variation in fossil mammal community structure (β diversity) is highest at intermediate values of continental mean annual precipitation (MAP) estimated from paleosols (∼ 450 mm/year) and declines under both wetter and drier conditions, reflecting diversity patterns of modern mammals. Latitudinal gradients in community change (latitudinal turnover gradients, aka LTGs) increase in strength through the Cenozoic, but also show a cyclical pattern that is significantly explained by MAP. In general, LTGs are weakest when continental MAP is highest, similar to modern tropical ecosystems in which latitudinal diversity gradients are weak or undetectable. Projections under modeled climate change show no substantial change in β diversity or LTG strength for North American mammals. Our results suggest that similar climate-mediated mechanisms might drive spatial and temporal patterns of community composition in both fossil and extant mammals. We also provide empirical evidence that the ecological processes on which climate space models are based are insufficient for accurately forecasting long-term mammalian response to anthropogenic climate change and inclusion of historical parameters may be essential.

  5. Human impacts flatten rainforest-savanna gradient and reduce adaptive diversity in a rainforest bird.

    Directory of Open Access Journals (Sweden)

    Adam H Freedman

    Full Text Available Ecological gradients have long been recognized as important regions for diversification and speciation. However, little attention has been paid to the evolutionary consequences or conservation implications of human activities that fundamentally change the environmental features of such gradients. Here we show that recent deforestation in West Africa has homogenized the rainforest-savanna gradient, causing a loss of adaptive phenotypic diversity in a common rainforest bird, the little greenbul (Andropadus virens. Previously, this species was shown to exhibit morphological and song divergence along this gradient in Central Africa. Using satellite-based estimates of forest cover, recent morphological data, and historical data from museum specimens collected prior to widespread deforestation, we show that the gradient has become shallower in West Africa and that A. virens populations there have lost morphological variation in traits important to fitness. In contrast, we find no loss of morphological variation in Central Africa where there has been less deforestation and gradients have remained more intact. While rainforest deforestation is a leading cause of species extinction, the potential of deforestation to flatten gradients and inhibit rainforest diversification has not been previously recognized. More deforestation will likely lead to further flattening of the gradient and loss of diversity, and may limit the ability of species to persist under future environmental conditions.

  6. Human impacts flatten rainforest-savanna gradient and reduce adaptive diversity in a rainforest bird.

    Science.gov (United States)

    Freedman, Adam H; Buermann, Wolfgang; Mitchard, Edward T A; Defries, Ruth S; Smith, Thomas B

    2010-09-30

    Ecological gradients have long been recognized as important regions for diversification and speciation. However, little attention has been paid to the evolutionary consequences or conservation implications of human activities that fundamentally change the environmental features of such gradients. Here we show that recent deforestation in West Africa has homogenized the rainforest-savanna gradient, causing a loss of adaptive phenotypic diversity in a common rainforest bird, the little greenbul (Andropadus virens). Previously, this species was shown to exhibit morphological and song divergence along this gradient in Central Africa. Using satellite-based estimates of forest cover, recent morphological data, and historical data from museum specimens collected prior to widespread deforestation, we show that the gradient has become shallower in West Africa and that A. virens populations there have lost morphological variation in traits important to fitness. In contrast, we find no loss of morphological variation in Central Africa where there has been less deforestation and gradients have remained more intact. While rainforest deforestation is a leading cause of species extinction, the potential of deforestation to flatten gradients and inhibit rainforest diversification has not been previously recognized. More deforestation will likely lead to further flattening of the gradient and loss of diversity, and may limit the ability of species to persist under future environmental conditions.

  7. Why do high-redshift galaxies show diverse gas-phase metallicity gradients?

    Science.gov (United States)

    Ma, Xiangcheng; Hopkins, Philip F.; Feldmann, Robert; Torrey, Paul; Faucher-Giguère, Claude-André; Kereš, Dušan

    2017-01-01

    Recent spatially resolved observations of galaxies at z ˜ 0.6-3 reveal that high-redshift galaxies show complex kinematics and a broad distribution of gas-phase metallicity gradients. To understand these results, we use a suite of high-resolution cosmological zoom-in simulations from the Feedback in Realistic Environments (FIRE) project, which include physically motivated models of the multi-phase ISM, star formation, and stellar feedback. Our simulations reproduce the observed diversity of kinematic properties and metallicity gradients, broadly consistent with observations at z ˜ 0-3. Strong negative metallicity gradients only appear in galaxies with a rotating disk, but not all rotationally supported galaxies have significant gradients. Strongly perturbed galaxies with little rotation always have flat gradients. The kinematic properties and metallicity gradient of a high-redshift galaxy can vary significantly on short time-scales, associated with starburst episodes. Feedback from a starburst can destroy the gas disk, drive strong outflows, and flatten a pre-existing negative metallicity gradient. The time variability of a single galaxy is statistically similar to the entire simulated sample, indicating that the observed metallicity gradients in high-redshift galaxies reflect the instantaneous state of the galaxy rather than the accretion and growth history on cosmological time-scales. We find weak dependence of metallicity gradient on stellar mass and specific star formation rate (sSFR). Low-mass galaxies and galaxies with high sSFR tend to have flat gradients, likely due to the fact that feedback is more efficient in these galaxies. We argue that it is important to resolve feedback on small scales in order to produce the diverse metallicity gradients observed.

  8. Environmental correlates of plant diversity in Korean temperate forests

    Science.gov (United States)

    Černý, Tomáš; Doležal, Jiří; Janeček, Štěpán; Šrůtek, Miroslav; Valachovič, Milan; Petřík, Petr; Altman, Jan; Bartoš, Michael; Song, Jong-Suk

    2013-02-01

    Mountainous areas of the Korean Peninsula are among the biodiversity hotspots of the world's temperate forests. Understanding patterns in spatial distribution of their species richness requires explicit consideration of different environmental drivers and their effects on functionally differing components. In this study, we assess the impact of both geographical and soil variables on the fine-scale (400 m2) pattern of plant diversity using field data from six national parks, spanning a 1300 m altitudinal gradient. Species richness and the slopes of species-area curves were calculated separately for the tree, shrub and herb layer and used as response variables in regression tree analyses. A cluster analysis distinguished three dominant forest communities with specific patterns in the diversity-environment relationship. The most widespread middle-altitude oak forests had the highest tree richness but the lowest richness of herbaceous plants due to a dense bamboo understory. Total richness was positively associated with soil reaction and negatively associated with soluble phosphorus and solar radiation (site dryness). Tree richness was associated mainly with soil factors, although trees are frequently assumed to be controlled mainly by factors with large-scale impact. A U-shaped relationship was found between herbaceous plant richness and altitude, caused by a distribution pattern of dwarf bamboo in understory. No correlation between the degree of canopy openness and herb layer richness was detected. Slopes of the species-area curves indicated the various origins of forest communities. Variable diversity-environment responses in different layers and communities reinforce the necessity of context-dependent differentiation for the assessment of impacts of climate and land-use changes in these diverse but intensively exploited regions.

  9. Genetic signatures of ecological diversity along an urbanization gradient

    Directory of Open Access Journals (Sweden)

    Ryan P. Kelly

    2016-09-01

    Full Text Available Despite decades of work in environmental science and ecology, estimating human influences on ecosystems remains challenging. This is partly due to complex chains of causation among ecosystem elements, exacerbated by the difficulty of collecting biological data at sufficient spatial, temporal, and taxonomic scales. Here, we demonstrate the utility of environmental DNA (eDNA for quantifying associations between human land use and changes in an adjacent ecosystem. We analyze metazoan eDNA sequences from water sampled in nearshore marine eelgrass communities and assess the relationship between these ecological communities and the degree of urbanization in the surrounding watershed. Counter to conventional wisdom, we find strongly increasing richness and decreasing beta diversity with greater urbanization, and similar trends in the diversity of life histories with urbanization. We also find evidence that urbanization influences nearshore communities at local (hundreds of meters rather than regional (tens of km scales. Given that different survey methods sample different components of an ecosystem, we then discuss the advantages of eDNA—which we use here to detect hundreds of taxa simultaneously—as a complement to traditional ecological sampling, particularly in the context of broad ecological assessments where exhaustive manual sampling is impractical. Genetic data are a powerful means of uncovering human-ecosystem interactions that might otherwise remain hidden; nevertheless, no sampling method reveals the whole of a biological community.

  10. Are there evolutionary consequences of plant-soil feedbacks along soil gradients?

    NARCIS (Netherlands)

    Schweitzer, J.A.; Juric, I.; Van de Voorde, T.F.J.; Clay, K.; Van der Putten, W.H.; Bailey, J.K.

    2014-01-01

    1Both abiotic and biotic gradients exist in soils, and several of these gradients have been shown to select for plant traits. Moreover, plants possess a multitude of traits that can lead to strong niche construction (i.e. plant-induced changes to soils). Our objectives in this paper are to outline b

  11. Use of topographic variability for assessing plant diversity in agricultural landscapes

    NARCIS (Netherlands)

    Hofer, G.; Bunce, R.G.H.; Edwards, P.J.; Szerencsits, E.; Wagner, H.H.; Herzog, F.

    2011-01-01

    The relationship between plant diversity and topographic variability in agricultural landscapes was investigated, with the aim of determining whether sampling landscape units of 1 km(2) (LUs) across a gradient of topographic variability is more efficient than a random design for assessing the range

  12. Comparison of plant diversity in protected and communal lands in the Bushbuckridge lowveld savanna, South Africa

    CSIR Research Space (South Africa)

    Shackleton, CM

    2000-07-01

    Full Text Available Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to land use, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge...

  13. Genomic and resistance gene homolog diversity of the dominant tallgrass prairie species across the U.S. Great Plains precipitation gradient.

    Directory of Open Access Journals (Sweden)

    Matthew N Rouse

    Full Text Available BACKGROUND: Environmental variables such as moisture availability are often important in determining species prevalence and intraspecific diversity. The population genetic structure of dominant plant species in response to a cline of these variables has rarely been addressed. We evaluated the spatial genetic structure and diversity of Andropogon gerardii populations across the U.S. Great Plains precipitation gradient, ranging from approximately 48 cm/year to 105 cm/year. METHODOLOGY/PRINCIPAL FINDINGS: Genomic diversity was evaluated with AFLP markers and diversity of a disease resistance gene homolog was evaluated by PCR-amplification and digestion with restriction enzymes. We determined the degree of spatial genetic structure using Mantel tests. Genomic and resistance gene homolog diversity were evaluated across prairies using Shannon's index and by averaging haplotype dissimilarity. Trends in diversity across prairies were determined using linear regression of diversity on average precipitation for each prairie. We identified significant spatial genetic structure, with genomic similarity decreasing as a function of distance between samples. However, our data indicated that genome-wide diversity did not vary consistently across the precipitation gradient. In contrast, we found that disease resistance gene homolog diversity was positively correlated with precipitation. SIGNIFICANCE: Prairie remnants differ in the genetic resources they maintain. Selection and evolution in this disease resistance homolog is environmentally dependent. Overall, we found that, though this environmental gradient may not predict genomic diversity, individual traits such as disease resistance genes may vary significantly.

  14. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    Directory of Open Access Journals (Sweden)

    Shan-Shan Qi

    Full Text Available The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%, compared with the native plants (over 60%. Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

  15. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

  16. The evolution of African plant diversity

    Directory of Open Access Journals (Sweden)

    Hans Peter Linder

    2014-07-01

    Full Text Available Sub-Saharan Africa includes some 45,000 plant species. The spatial patterns of this diversity have been well explored. We can group the species into a set of biogeographical regions (largely co-incident with regions defined for terrestrial vertebrate groups. Furthermore, we know that the diversity is unevenly distributed, with southern Africa (especially the south-western tip disproportionally species rich, while the West African interior is disproportionally species poor. However, the origins of this diversity have only been explored for two anomalous African Floras (the Tropic-alpine Flora and the Cape Flora, whereas the origins of the diversity of the other floras are still unknown. Here I argue that six floras, with distinct geographical centres, different extra-African affinities, ages of radiation and radiation rates, can be delimited: the Austro-temperate, Tropic-alpine, Lowland forest, Tropic-montane, Savanna and Arid Floras. The oldest flora may be the Lowland forest Flora, and the most recent is the Tropic-alpine, which probably evolved during the Plio-Pleistocene on the summits of the East Africa volcanoes. My results suggest that the most rapidly radiating flora is the Austro-temperate Flora, while the other floras are all diversifying at more or less the same rate, this is also consistent with the current massive species richness in this flora (about half of the African species richness. The Austro-temperate Flora appears to be related to the floras of the other southern continents, the Tropic-alpine Flora to that of the Northern Hemisphere, and the four tropical floras to the tropical regions of the other continents, consistent with the theory of phylogenetic niche conservatism. Current African diversity may be the result of the sequential adding of new floras to the continent. Possibly the species poverty especially of the Lowland forest Flora may be the result of the spread of C4 grasslands and associated regular fires.

  17. 若尔盖高原退化沼泽群落植物多样性及种间相关性沿排水梯度的变化%Changes of plant species diversity, and interspecific correlation in a degraded swamp community along drainage gradients on the Zoig(e) Plateau of China

    Institute of Scientific and Technical Information of China (English)

    韩大勇; 杨永兴; 杨杨

    2012-01-01

    植物多样性与种间相关性是植物群落生态学和生物多样性研究的核心问题,然而有关二者之间关系的综合研究尚不多见.该文以若尔盖高原排水干扰下不同退化阶段的沼泽湿地植被为研究对象,应用Spearman秩相关、回归分析等方法,分析了沼泽植物群落物种多样性和种间相关性的变化及二者相互关系.结果表明:沿排水梯度,从相对原生沼泽至极度退化沼泽,不同植物种群均有其特定的生态分布范围;群落总种数、样方物种丰富度、Shannon-Wiener指数和Whittaker指数均单调增加;植物种间相关强度增加;正相关种对比例呈逐渐增加的趋势,以极重度和极度退化阶段的较高,相对原生沼泽和轻度退化阶段的较低,负相关种对比例的变化趋势与之相反;Shannon-Wiener指数与正负相关种对比例均具有显著线性关系(p<0.05),Whittaker指数均无显著关系(p>0.05).人为排水作用通过提高群落生境异质性,促进正相关种对的共存,增加沼泽群落植物多样性.%Aims Plant species diversity and interspecific correlation are central topics in phytocoenology and biodiversity science. Our objective is to study the dynamics and interrelationships of plant species diversity and interspecific correlation in a Zoige Plateau swamp community at different stages of degradation caused by anthropogenic drainage. Methods Spearman's rank correlation and regression analysis were employed to analyze plant species diversity and interspecific correlation as well as their relationship. Important findings Along drainage gradients from relatively pristine swamp to extremely degraded swamp, different plant species had restricted ecological distributions. The total number of species, species richness per quadrat, Shannon-Wiener index and Whittaker index all increased monotonically, and the intensity of interspecific correlation increased in general. The proportion of species pairs

  18. Contrasting species-environment relationships in communities of testate amoebae, bryophytes and vascular plants along the fen-bog gradient.

    Science.gov (United States)

    Lamentowicz, Mariusz; Lamentowicz, Lukasz; van der Knaap, Willem O; Gabka, Maciej; Mitchell, Edward A D

    2010-04-01

    We studied the vegetation, testate amoebae and abiotic variables (depth of the water table, pH, electrical conductivity, Ca and Mg concentrations of water extracted from mosses) along the bog to extremely rich fen gradient in sub-alpine peatlands of the Upper Engadine (Swiss Alps). Testate amoeba diversity was correlated to that of mosses but not of vascular plants. Diversity peaked in rich fen for testate amoebae and in extremely rich fen for mosses, while for testate amoebae and mosses it was lowest in bog but for vascular plants in extremely rich fen. Multiple factor and redundancy analyses (RDA) revealed a stronger correlation of testate amoebae than of vegetation to water table and hydrochemical variables and relatively strong correlation between testate amoeba and moss community data. In RDA, hydrochemical variables explained a higher proportion of the testate amoeba and moss data than water table depth. Abiotic variables explained a higher percentage of the species data for testate amoebae (30.3% or 19.5% for binary data) than for mosses (13.4%) and vascular plants (10%). These results show that (1) vascular plant, moss and testate amoeba communities respond differently to ecological gradients in peatlands and (2) testate amoebae are more strongly related than vascular plants to the abiotic factors at the mire surface. These differences are related to vertical trophic gradients and associated niche differentiation.

  19. Conservation of Genetic Diversity in Culture Plants

    Directory of Open Access Journals (Sweden)

    MAXIM A.

    2010-08-01

    Full Text Available The most important international document relating to the conservation of biodiversity is one adopted by theUN in Rio de Janeiro (1992 that "Convention on Biodiversity". Based on this agreement, the EU has taken a series ofmeasures to reduce genetic erosion in agriculture, which grew with the expansion of industrialized agriculture.Throughout its existence, mankind has used some 10,000 growing plant species. According to FAO statistics, today,90% of food production is ensured by some 120 growing plant species. In addition to drastic reduction in specificdiversity, the advent of industrialized agriculture has generated a process of strong genetic erosion. Old varieties andlocal varieties of crops have mostly been affected, in favour of "modern" varieties. Landraces are characterized by highheterogenity. They have the advantage of being much better adapted to biotic and abiotic stress conditions (diseases,pests, drought, low in nutrients, etc. and have excellent taste qualities, which can justify a higher price recovery thancommercial varieties. Thanks to these features, these crops need small inputs, which correspond to the concept ofsustainable development. Landraces are an invaluable genetic potential for obtaining new varieties of plants and are bestsuited for crop cultivation in ecological systems, becoming more common. Also, for long term food security in thecontext of global warming, rich genetic diversity will be require. “In situ” and “ex situ” conservation are the two majorstrategies used in the conservation of plant genetic resources. There is a fundamental difference between these twostrategies: “ex situ” conservation involves sampling, transfer and storage of a particular species population away fromthe original location, while “in situ” conservation (in their natural habitat implies that the varieties of interest,management and monitoring their place of origin takes place in the community to which they belong. These

  20. Sapling herbivory, invertebrate herbivores and predators across a natural tree diversity gradient in Germany's largest connected deciduous forest.

    Science.gov (United States)

    Sobek, Stephanie; Scherber, Christoph; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2009-05-01

    Tree species-rich forests are hypothesised to be less susceptible to insect herbivores, but so far herbivory-diversity relationships have rarely been tested for tree saplings, and no such study has been published for deciduous forests in Central Europe. We expected that diverse tree communities reduce the probability of detection of host plants and increase abundance of predators, thereby reducing herbivory. We examined levels of herbivory suffered by beech (Fagus sylvatica L.) and maple saplings (Acer pseudoplatanus L. and Acer platanoides L.) across a tree species diversity gradient within Germany's largest remaining deciduous forest area, and investigated whether simple beech or mixed stands were less prone to damage caused by herbivorous insects. Leaf area loss and the frequency of galls and mines were recorded for 1,040 saplings (>13,000 leaves) in June and August 2006. In addition, relative abundance of predators was assessed to test for potential top-down control. Leaf area loss was generally higher in the two species of maple compared to beech saplings, while only beech showed a decline in damage caused by leaf-chewing herbivores across the tree diversity gradient. No significant patterns were found for galls and mines. Relative abundance of predators on beech showed a seasonal response and increased on species-rich plots in June, suggesting higher biological control. We conclude that, in temperate deciduous forests, herbivory-tree diversity relationships are significant, but are tree species-dependent with bottom-up and top-down control as possible mechanisms. In contrast to maple, beech profits from growing in a neighbourhood of higher tree richness, which implies that species identity effects may be of greater importance than tree diversity effects per se. Hence, herbivory on beech appeared to be mediated bottom-up by resource concentration in the sampled forest stands, as well as regulated top-down through biocontrol by natural enemies.

  1. Differences in forest plant functional trait distributions across land-use and productivity gradients

    Science.gov (United States)

    Margaret M. Mayfield; John M. Dwyer; Loic Chalmandrier; Jessie A. Wells; Stephen P. Bonser; Carla P. Catterall; Fabrice DeClerck; Yi Ding; Jennifer M. Fraterrigo; Daniel J. Metcalfe; Cibele Queiroz; Peter A. Vesk; John W. Morgan

    2013-01-01

    • Premise of study: Plant functional traits are commonly used as proxies for plant responses to environmental challenges, yet few studies have explored how functional trait distributions differ across gradients of land-use change. By comparing trait distributions in intact forests with those across land-use change gradients, we can improve our understanding of the ways...

  2. Functionally and phylogenetically diverse plant communities key to soil biota.

    Science.gov (United States)

    Milcu, Alexandru; Allan, Eric; Roscher, Christiane; Jenkins, Tania; Meyer, Sebastian T; Flynn, Dan; Bessler, Holger; Buscot, François; Engels, Christof; Gubsch, Marlén; König, Stephan; Lipowsky, Annett; Loranger, Jessy; Renker, Carsten; Scherber, Christoph; Schmid, Bernhard; Thébault, Elisa; Wubet, Tesfaye; Weisser, Wolfgang W; Scheu, Stefan; Eisenhauer, Nico

    2013-08-01

    Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity--ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset of a grassland biodiversity experiment. Plant functional and phylogenetic diversity were generally better predictors of soil biota than the traditionally used species or functional group richness. Functional diversity was a reliable predictor for most biota, with the exception of soil microorganisms, which were better predicted by phylogenetic diversity. These results provide empirical support for the idea that the diversity of plant functional traits and the diversity of evolutionary lineages in a community are important for maintaining higher abundances and diversity of soil communities.

  3. Cenozoic plant diversity of Yunnan: A review

    Directory of Open Access Journals (Sweden)

    Yongjiang Huang

    2016-12-01

    Full Text Available Yunnan in southwestern China is renowned for its high plant diversity. To understand how this modern botanical richness formed, it is critical to investigate the past biodiversity throughout the geological time. In this review, we present a summary on plant diversity, floristics and climates in the Cenozoic of Yunnan and document their changes, by compiling published palaeobotanical sources. Our review demonstrates that thus far a total of 386 fossil species of ferns, gymnosperms and angiosperms belonging to 170 genera within 66 families have been reported from the Cenozoic, particularly the Neogene, of Yunnan. Angiosperms display the highest richness represented by 353 species grouped into 155 genera within 60 families, with Fagaceae, Fabaceae, Lauraceae and Juglandaceae being the most diversified. Most of the families and genera recorded as fossils still occur in Yunnan, but seven genera have disappeared, including Berryophyllum, Cedrelospermum, Cedrus, Palaeocarya, Podocarpium, Sequoia and Wataria. The regional extinction of these genera is commonly referred to an aridification of the dry season associated with Asian monsoon development. Floristic analyses indicate that in the late Miocene, Yunnan had three floristic regions: a northern subtropical floristic region in the northeast, a subtropical floristic region in the east, and a tropical floristic region in the southwest. In the late Pliocene, Yunnan saw two kinds of floristic regions: a subalpine floristic region in the northwest, and two subtropical floristic regions separately in the southwest and the eastern center. These floristic concepts are verified by results from our areal type analyses which suggest that in the Miocene southwestern Yunnan supported the most Pantropic elements, while in the Pliocene southwestern Yunnan had abundant Tropical Asia (Indo–Malaysia type and East Asia and North America disjunct type that were absent from northwestern Yunnan. From the late Miocene to

  4. Spatial distribution patterns of wetland plants in relation to environmental gradient in the Honghe National Nature Reserve, Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Demin; LUAN Zhaoqing; GUO Xiaoyu; LOU Yanjing

    2012-01-01

    Quantifying correlation between the spatial patterns of natural wetland plants and environmental gradient gives better understanding of wetland habitats,which is the fundamental for the strategy making on the protection and restoration of natural wetlands.In this study,the spatial patterns of wetland plants and the environmental gradient of wetland habitats were assessed in the Honghe National Nature Reserve (HNNR) in Northeast China,a wetland of international importance on the Ramsar list.Biophysical parameters' values of wetland plants were obtained by field sampling methods,and wetland mapping at the community scale was completed using remote sensing techniques.Digital delineation of the surface water system,hydrological zoning and wetness index were produced by spatial analysis methods in Geographic Information System.An ecological ordination method and two clustering methods were used to quantify the relationship between the spatial distribution patterns of wetland plants and the corresponding environmental gradients.Such quantitative analyses also present the specific diversity of different types of wetland plants based on the environmental attributes of their habitats.With the support from modern geo-information techniques,the experimental results indicate how four ecotypes of wetland plants spatially transit from forest swamp,shrub wetland and meadow into marsh wetland with increasing wetness index and water table.And they also show how wetland spatial distribution patterns are controlled by an environmental gradient of wetness.Another key finding of this research work is that our results present the exact fundamental differences between marsh and non-marsh plants of 11 wetland plant communities within the core study area.Hence,this case study gives a good sample for better understanding of the complex correlation between the spatial patterns of wetland plants and their environmental attributes using advanced digital analysis methods.It is also useful to

  5. Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

    Science.gov (United States)

    Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

    2012-12-01

    This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients

  6. Effect of plant diversity on the diversity of soil organic compounds

    Science.gov (United States)

    El Moujahid, Lamiae; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

    2017-01-01

    The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms. PMID:28166250

  7. Effect of plant diversity on the diversity of soil organic compounds.

    Science.gov (United States)

    El Moujahid, Lamiae; Le Roux, Xavier; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

    2017-01-01

    The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms.

  8. Global gradients in vertebrate diversity predicted by historical area-productivity dynamics and contemporary environment.

    Directory of Open Access Journals (Sweden)

    Walter Jetz

    Full Text Available Broad-scale geographic gradients in species richness have now been extensively documented, but their historical underpinning is still not well understood. While the importance of productivity, temperature, and a scale dependence of the determinants of diversity is broadly acknowledged, we argue here that limitation to a single analysis scale and data pseudo-replication have impeded an integrated evolutionary and ecological understanding of diversity gradients. We develop and apply a hierarchical analysis framework for global diversity gradients that incorporates an explicit accounting of past environmental variation and provides an appropriate measurement of richness. Due to environmental niche conservatism, organisms generally reside in climatically defined bioregions, or "evolutionary arenas," characterized by in situ speciation and extinction. These bioregions differ in age and their total productivity and have varied over time in area and energy available for diversification. We show that, consistently across the four major terrestrial vertebrate groups, current-day species richness of the world's main 32 bioregions is best explained by a model that integrates area and productivity over geological time together with temperature. Adding finer scale variation in energy availability as an ecological predictor of within-bioregional patterns of richness explains much of the remaining global variation in richness at the 110 km grain. These results highlight the separate evolutionary and ecological effects of energy availability and provide a first conceptual and empirical integration of the key drivers of broad-scale richness gradients. Avoiding the pseudo-replication that hampers the evolutionary interpretation of non-hierarchical macroecological analyses, our findings integrate evolutionary and ecological mechanisms at their most relevant scales and offer a new synthesis regarding global diversity gradients.

  9. Bryophyte diversity and range size distribution along two altitudinal gradients: Continent vs. island

    Science.gov (United States)

    Ah-Peng, Claudine; Wilding, Nicholas; Kluge, Juergen; Descamps-Julien, Blandine; Bardat, Jacques; Chuah-Petiot, Min; Strasberg, Dominique; Hedderson, Terry A. J.

    2012-07-01

    We compare patterns of bryophyte diversity and variation in species altitudinal ranges between a continental and an island altitudinal gradient. We use our ecological data set along the highest summit (Piton des Neiges, 3069 m) of Réunion Island (Mascarene archipelago) and compare it to available published data of another high volcanic massif in Colombia (Nevado del Ruiz, 5321 m). The distribution of narrow-ranged and large-ranged species was investigated. We tested the effect of geometric constraints on species distribution along the two gradients by comparing empirical to predicted data using the Mid-Domain Null Programme (McCain, 2004). Species richness was comparable between the island and continental gradient for epiphytic bryophytes, 265 and 295 species respectively. The comparison between the two tropical high mountains demonstrates important differences in the distribution of range sizes with altitude and a dominance of species with small range sizes on the Réunion gradient. For the island gradient, mean altitudinal range increases with altitude whilst concurrently species richness decreases revealing a Rapoport effect in altitudinal distribution of bryophyte communities. Geometric constraints did not explain much of the species richness pattern for the island. Conversely, for the continental gradient, dominated by large-ranged species, geometric constraints could not be ruled out as a primary structuring feature for the species richness pattern. This study also highlights that the island's cloud forest hosts not only high species richness but also high number of rare species, which is of prime interest for conservation planners.

  10. Plant species diversity in a changing agricultural landscape: the ...

    African Journals Online (AJOL)

    Key words: Coffee plantation, plant species diversity, agroecosystem, vascular plants. Introduction. One of the ... Tbe livestock reared include cattle, goats, sheep, pigs and poultry. ... Assessment of trees, shrubs and grasses. Transects 500 m ...

  11. Allelic diversity associated with aridity gradient in wild emmer wheat populations.

    Science.gov (United States)

    Peleg, Zvi; Saranga, Yehoshua; Krugman, Tamar; Abbo, Shahal; Nevo, Eviatar; Fahima, Tzion

    2008-01-01

    The association between allelic diversity and ecogeographical variables was studied in natural populations of wild emmer wheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell.], the tetraploid progenitor of cultivated wheat. Patterns of allelic diversity in 54 microsatellite loci were analyzed in a collection of 145 wild emmer wheat accessions representing 25 populations that were sampled across naturally occurring aridity gradient in Israel and surrounding regions. The obtained results revealed that 56% of the genetic variation resided among accessions within populations, while only 44% of the variation resided between populations. An unweighted pair-group method analysis (UPGMA) tree constructed based on the microsatellite allelic diversity divided the 25 populations into six major groups. Several groups were comprised of populations that were collected in ecologically similar but geographically remote habitats. Furthermore, genetic differentiation between populations was independent of the geographical distances. An interesting evolutionary phenomenon is highlighted by the unimodal relationship between allelic diversity and annual rainfall (r = 0.74, P < 0.0002), indicating higher allelic diversity in populations originated from habitats with intermediate environmental stress (i.e. rainfall 350-550 mm year(-1)). These results show for the first time that the 'intermediate-disturbance hypothesis', explaining biological diversity at the ecosystem level, also dominates the genetic diversity within a single species, the lowest hierarchical element of the biological diversity.

  12. [Research progress on plant diversity conservation in sand dune areas].

    Science.gov (United States)

    Liu, Zhi-min; Ma, Jun-ling

    2008-01-01

    The landscape in sand dune areas is characterized by the alternate distribution of sand dune and interdune lowland, and the unique floras in these areas are some endemic or rare plant species. In recent years, the decrease in plant species richness and the disappearance of some endemic or rare plant species in these areas have been received special attention, which were listed in the Program of International Biodiversity Conservation, and studied in many countries and districts. In this paper, the research progress in these fields was summarized from the aspects of significance of plant diversity conservation, formation mechanisms of plant diversity, ways of plant diversity conservation, roles of plant diversity research in the development of ecological theories, and important issues in operating plant diversity conservation project. To conserve plant diversity in sand dune areas, attentions should be paid to the differences in conservation goals (to maintain high species richness or to conserve endemic or rare species) among different regions, and the balances between the stabilization of active sand and the conservation of endemic or rare species, and the maintenance of high species richness and the conservation of endemic or rare species. It needed also to consider the sand dune and the interdune lowland as a unified landscape unit to explore the impacts of disturbances and habitat fragment on plant diversity.

  13. Flood disturbance and predator-prey effects on regional gradients in species diversity.

    Science.gov (United States)

    Mori, Terutaka; Saitoh, Takashi

    2014-01-01

    The effects of both abiotic factors and biotic interactions among guilds (i.e., inter-guild effects) have been suggested to be important for understanding spatial variation in species diversity; however, compared to the abiotic effects, the processes by which the inter-guild effects are mediated have been little described. Hence, we investigated stream invertebrate assemblages on Hokkaido Island, Japan, and assessed how the processes of determining regional patterns in species diversity differed among guilds (collector-filterers, collector-gatherers/shredders, scrapers, and predators) by taking both inter-guild and abiotic effects into consideration using Bayesian networks. Collector-gatherers/shredders, collector-filterers, and predators exhibited significant regional gradients in taxonomic richness. Gradients in the former two guilds can be generated by variation in flood disturbance regardless of interactions with other guilds. The gradient in predator taxonomic richness was indirectly related to the disturbance and was directly generated by bottom-up effects through their prey (collector-gatherers/shredders and collector-filterers). We found that not only environmental factors, but also inter-guild effects may be essential for forming the regional gradient in predators, unlike those for collector-gatherers/shredders and collector-filterers. The processes underlying the regional variation in taxonomic richness of the three guilds are interpreted in terms of the "more individuals" hypothesis, facilitation, and predator-prey relationships.

  14. Emerging dragonfly diversity at small Rhode Island (U.S.A.) wetlands along an urbanization gradient

    Science.gov (United States)

    Aliberti Lubertazzi, Maria A.; Ginsberg, Howard S.

    2010-01-01

    Natal habitat use by dragonflies was assessed on an urban to rural land-use gradient at a set of 21 wetlands, during two emergence seasons (2004, 2005). The wetlands were characterized for urbanization level by using the first factor from a principal components analysis combining chloride concentration in the wetland and percent forest in the surrounding buffer zone. Measurements of species diversity and its components (species richness and evenness) were analyzed and compared along the urbanization gradient, as were distributions of individual species. Dragonfly diversity, species richness, and evenness did not change along the urbanization gradient, so urban wetlands served as natal habitat for numerous dragonfly species. However, several individual species displayed strong relationships to the degree of urbanization, and most were more commonly found at urban sites and at sites with fish. In contrast, relatively rare species were generally found at the rural end of the gradient. These results suggest that urban wetlands can play important roles as dragonfly habitat and in dragonfly conservation efforts, but that conservation of rural wetlands is also important for some dragonfly species.

  15. Drivers of carabid functional diversity: abiotic environment, plant functional traits, or plant functional diversity?

    Science.gov (United States)

    Pakeman, Robin J; Stockan, Jenni A

    2014-05-01

    Understanding how community assembly is controlled by the balance of abiotic drivers (environment or management) and biotic drivers (community composition of other groups) is important in predicting the response of ecosystems to environmental change. If there are strong links between plant assemblage structure and carabid beetle functional traits and functional diversity, then it is possible to predict the impact of environmental change propagating through different functional and trophic groups. Vegetation and pitfall trap beetle surveys were carried out across twenty four sites contrasting in land use, and hence productivity and disturbance regime. Plant functional traits were very successful at explaining the distribution of carabid functional traits across the habitats studied. Key carabid response traits appeared to be body length and wing type. Carabid functional richness was significantly smaller than expected, indicating strong environmental filtering, modulated by management, soil characteristics, and by plant response traits. Carabid functional divergence was negatively related to plant functional evenness, while carabid functional evenness was positively correlated to plant functional evenness and richness. The study shows that there are clear trait linkages between the plant and the carabid assemblage that act not only through the mean traits displayed, but also via their distribution in trait space; powerful evidence that both the mean and variance of traits in one trophic group structure the assemblage of another.

  16. Understanding crop genetic diversity under modern plant breeding.

    Science.gov (United States)

    Fu, Yong-Bi

    2015-11-01

    Maximizing crop yield while at the same time minimizing crop failure for sustainable agriculture requires a better understanding of the impacts of plant breeding on crop genetic diversity. This review identifies knowledge gaps and shows the need for more research into genetic diversity changes under plant breeding. Modern plant breeding has made a profound impact on food production and will continue to play a vital role in world food security. For sustainable agriculture, a compromise should be sought between maximizing crop yield under changing climate and minimizing crop failure under unfavorable conditions. Such a compromise requires better understanding of the impacts of plant breeding on crop genetic diversity. Efforts have been made over the last three decades to assess crop genetic diversity using molecular marker technologies. However, these assessments have revealed some temporal diversity patterns that are largely inconsistent with our perception that modern plant breeding reduces crop genetic diversity. An attempt was made in this review to explain such discrepancies by examining empirical assessments of crop genetic diversity and theoretical investigations of genetic diversity changes over time under artificial selection. It was found that many crop genetic diversity assessments were not designed to assess diversity impacts from specific plant breeding programs, while others were experimentally inadequate and contained technical biases from the sampling of cultivars and genomes. Little attention has been paid to theoretical investigations on crop genetic diversity changes from plant breeding. A computer simulation of five simplified breeding schemes showed the substantial effects of plant breeding on the retention of heterozygosity over generations. It is clear that more efforts are needed to investigate crop genetic diversity in space and time under plant breeding to achieve sustainable crop production.

  17. Large herbivores change the direction of interactions within plant communities along a salt marsh stress gradient

    NARCIS (Netherlands)

    Howison, Ruth A.; Olff, Han; Steever, Rutger; Smit, Christian

    2015-01-01

    Question: How multiple abiotic stress factors combined with herbivory affect interactions within plant communities is poorly understood. We ask how large herbivore grazing affects the direction of plant-plant interactions along an environmental gradient in a salt marsh. Location: Grazed (cattle) and

  18. Bacterial community of cushion plant Thylacospermum ceaspitosum on elevational gradient in the Himalayan cold desert.

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    Klára eŘeháková

    2015-04-01

    Full Text Available Although bacterial assemblages are important components of soils in arid ecosystems, the knowledge about composition, life-strategies and environmental drivers is still fragmentary, especially in remote high-elevation mountains. We compared the quality and quantity of heterotrophic bacterial assemblages between the rhizosphere of the dominant cushion-forming plant Thylacospermum ceaspitosum and its surrounding bulk soil in two mountain ranges (East Karakoram: 4850–5250 m and Little Tibet: 5350–5850 m, in communities from cold steppes to the subnival zone in Ladakh, arid Trans-Himalaya, northwest India. Bacterial communities were characterized by molecular fingerprinting in combination with culture-dependent methods. The effects of environmental factors (elevation, mountain range, and soil physico-chemical parameters on the bacterial community composition and structure were tested by multivariate redundancy analysis and conditional inference trees. Actinobacteria dominate the cultivable part of community and represent a major bacterial lineage of cold desert soils. The most abundant genera were Streptomyces, Arthrobacter and Paenibacillus, representing both r- and K- strategists. The soil texture is the most important factor for the community structure and the total bacteria counts. Less abundant and diverse assemblages are found in East Karakoram with coarser soils derived from leucogranite bedrock, while more diverse assemblages in Little Tibet are associated with finer soils derived from easily weathering gneisses. Cushion rhizosphere is in general less diverse than bulk soil, and contains more r-strategists. K-strategists are more associated with the extremes of the gradient, with drought at lowest elevations (4850 - 5000 m and frost at the highest elevations (5750 - 5850 m. The present study illuminates the composition of soil bacterial assemblages in relation to the cushion plant Thylacospermum ceaspitosum in a xeric environment and

  19. Resilience of Amazon forests emerges from plant trait diversity

    Science.gov (United States)

    Sakschewski, Boris; von Bloh, Werner; Boit, Alice; Poorter, Lourens; Peña-Claros, Marielos; Heinke, Jens; Joshi, Jasmin; Thonicke, Kirsten

    2016-11-01

    Climate change threatens ecosystems worldwide, yet their potential future resilience remains largely unquantified. In recent years many studies have shown that biodiversity, and in particular functional diversity, can enhance ecosystem resilience by providing a higher response diversity. So far these insights have been mostly neglected in large-scale projections of ecosystem responses to climate change. Here we show that plant trait diversity, as a key component of functional diversity, can have a strikingly positive effect on the Amazon forests' biomass under future climate change. Using a terrestrial biogeochemical model that simulates diverse forest communities on the basis of individual tree growth, we show that plant trait diversity may enable the Amazon forests to adjust to new climate conditions via a process of ecological sorting, protecting the Amazon's carbon sink function. Therefore, plant trait diversity, and biodiversity in general, should be considered in large-scale ecosystem projections and be included as an integral part of climate change research and policy.

  20. Metabolic diversity and microbial biomass in forest soils across climatic and tree species diversity gradients

    OpenAIRE

    Carnol, Monique; Bosman, Bernard; Vanoppen, Astrid; De Wandeler, Hans; Muys, Bart

    2013-01-01

    The biogeochemical cycling in forest ecosystems is highly dependent on the interactions between plants and soil. Tree species affect element cycling through deposition in throughfall, litterfall, microbial activities in soil and rhizosphere processes. Tree species diversification has been suggested for maintaining forest ecosystem services and combining provisioning and supporting services within multifunctional and sustainable forestry. However, the understanding of the role of biodiversity ...

  1. Temporal dynamics of deep-sea latitudinal species diversity gradient based on paleoceanographic/micropaleontologic data

    Science.gov (United States)

    Yasuhara, M.; Hunt, G.; Okahashi, H.

    2009-12-01

    Macroecology investigates large-scale ecological phenomena, such as regional-global trends in ecosystem properties and biodiversity, and is used to better understand recent human-induced ecosystem degradation. Paleoceanography investigates physical/chemical parameters, biogeochemical cycles, ocean circulation, and ocean-atmosphere interaction, but rarely includes ecosystem-scale biological processes. Here we adopt a macroecological approach to paleoceanography and present sediment core records of the temporal dynamics of deep-sea species diversity gradients using ostracodes from the equatorial Atlantic Ocean for the past four glacial-interglacial cycles. Results show unexpected instability and high amplitude fluctuations in species diversity in the tropical deep ocean. The results imply that the modern deep-sea latitudinal species diversity gradient is unexpectedly dynamic over short time intervals and collapsed during glacial periods. Unstable tropical diversity requires reconsideration of current ecological hypotheses about the generation and maintenance of biodiversity as they apply to the deep sea, and underscores the potential vulnerability and conservation importance of tropical deep-sea ecosystems.

  2. Diversity and distribution of higher plants in Yunnan, China

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    Li Chen

    2013-05-01

    Full Text Available Yunnan Province is a biodiversity hotspot in China that has global significance. In order to further recognize and protect the biodiversity of Yunnan, we examined the basic distributional pattern of its plant diversity based on Flora Yunnanica. According to our analysis, Northwest Yunnan had the highest plant diversity, with Yulong County the most diverse, containing 4,358 species of higher plants, followed by Gongshan County and Xianggelila County, which had 3,981 and 3,874 higher plants respectively. The tropical edge region of southern Yunnan, represented by Xishuangbanna, had the second highest level of diversity, with Mengla County and Jinghong County containing more than 3,000 higher plant species. In contrast, the plant diversity of Eastern and Central Yunnan, comprising mainly the Yunnan Plateau, was deemed relatively poor, possibly reflecting lower attention and field surveys by botanists. Both the distribution patterns of endemic and narrow-ranging species were similar to that for all plants. Yunnan contains 4,008 endemic and 4,509 narrow-ranging species with Gongshan County being most diverse, having more than 500 narrow-ranging species. Most species (64.1% were distributed in less than five counties in Yunnan, and 46.0% could only be found in one. Our analysis reveals that previous field surveys of Yunnan’s plant diversity did not fully reflect the natural zonal regularity and consequently further investigation is warranted. Some narrow-ranging species will be endangered without protection.

  3. Functionally and phylogenetically diverse plant communities key to soil biota

    OpenAIRE

    Milcu, Alexandru; Allan, Eric; Roscher, Christiane; Jenkins, Tania; Sebastian T Meyer; Flynn, Dan; Bessler, Holger; Buscot, François; Engels, Christof; Gubsch, Marlén; König, Stephan; Lipowsky, Annett; Loranger, Jessy; Renker, Carsten; Scherber, Christoph

    2013-01-01

    Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity–ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset ...

  4. Plant trait variation along an altitudinal gradient in mediterranean high mountain grasslands: controlling the species turnover effect.

    Science.gov (United States)

    Pescador, David S; de Bello, Francesco; Valladares, Fernando; Escudero, Adrián

    2015-01-01

    Assessing changes in plant functional traits along gradients is useful for understanding the assembly of communities and their response to global and local environmental drivers. However, these changes may reflect the effects of species composition (i.e. composition turnover), species abundance (i.e. species interaction), and intra-specific trait variability (i.e. species plasticity). In order to determine the relevance of the latter, trait variation can be assessed under minimal effects of composition turnover. Nine sampling sites were established along an altitudinal gradient in a Mediterranean high mountain grassland community with low composition turnover (Madrid, Spain; 1940 m-2419 m). Nine functional traits were also measured for ten individuals of around ten plant species at each site, for a total of eleven species across all sites. The relative importance of different sources of variability (within/between site and intra-/inter-specific functional diversity) and trait variation at species and community level along the considered gradients were explored. We found a weak individual species response to altitude and other environmental variables although in some cases, individuals were smaller and leaves were thicker at higher elevations. This lack of species response was most likely due to greater within- than between-site species variation. At the community level, inter-specific functional diversity was generally greater than the intra-specific component except for traits linked to leaf element content (leaf carbon content, leaf nitrogen content, δ13C and δ15N). Inter-specific functional diversity decreased with lower altitude for four leaf traits (specific leaf area, leaf dry matter content, δ13C and δ15N), suggesting trait convergence between species at lower elevations, where water shortage may have a stronger environmental filtering effect than colder temperatures at higher altitudes. Our results suggest that, within a vegetation type encompassing

  5. Conservation status affects elevational gradient in bird diversity in the Himalaya: A new perspective

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    Prakash Kumar Paudel

    2014-12-01

    Full Text Available Understanding diversity patterns along altitudinal gradients, and their underlying causes are important for conserving biodiversity. Previous studies have focused on climatic, energetic, and geographic variables (e.g., mid-domain effects, with less attention paid to human-induced habitat modifications. We used published data of bird distributions along an elevational gradient (0–4900 m in the Nepalese Himalaya and interpolated species presence between elevational limits. The relationship between species richness and environmental variables was analyzed using generalized linear models. A low plateau relationship between bird richness and elevation was observed, with a main peak at intermediate elevations (2800 m. Across the total gradient, interpolated bird species richness had a unimodal relationship to maximum monthly precipitation and a linear response to seasonal variation in temperature, proportion of forest cover, and proportion of protected area. In lower elevations (0–2800 m, interpolated species richness had a positive and linear response to the proportion of Ramsar sites and a unimodal response to habitat heterogeneity. At higher elevations (2900–4900 m, interpolated bird richness had a positive linear response to monthly variation in temperature and a negative linear response to proportion forest cover. We conclude that factors related to human management are important drivers of elevational gradients in bird species richness.

  6. Plant diversity effects on root decomposition in grasslands

    Science.gov (United States)

    Chen, Hongmei; Mommer, Liesje; van Ruijven, Jasper; de Kroon, Hans; Gessler, Arthur; Scherer-Lorenzen, Michael; Wirth, Christian; Weigelt, Alexandra

    2016-04-01

    Loss of plant diversity impairs ecosystem functioning. Compared to other well-studied processes, we know little about whether and how plant diversity affects root decomposition, which is limiting our knowledge on biodiversity-carbon cycling relationships in the soil. Plant diversity potentially affects root decomposition via two non-exclusive mechanisms: by providing roots of different substrate quality and/or by altering the soil decomposition environment. To disentangle these two mechanisms, three decomposition experiments using a litter-bag approach were conducted on experimental grassland plots differing in plant species richness, functional group richness and functional group composition (e.g. presence/absence of grasses, legumes, small herbs and tall herbs, the Jena Experiment). We studied: 1) root substrate quality effects by decomposing roots collected from the different experimental plant communities in one common plot; 2) soil decomposition environment effects by decomposing standard roots in all experimental plots; and 3) the overall plant diversity effects by decomposing community roots in their 'home' plots. Litter bags were installed in April 2014 and retrieved after 1, 2 and 4 months to determine the mass loss. We found that mass loss decreased with increasing plant species richness, but not with functional group richness in the three experiments. However, functional group presence significantly affected mass loss with primarily negative effects of the presence of grasses and positive effects of the presence of legumes and small herbs. Our results thus provide clear evidence that species richness has a strong negative effect on root decomposition via effects on both root substrate quality and soil decomposition environment. This negative plant diversity-root decomposition relationship may partly account for the positive effect of plant diversity on soil C stocks by reducing C loss in addition to increasing primary root productivity. However, to fully

  7. Fungal disease incidence along tree diversity gradients depends on latitude in European forests.

    Science.gov (United States)

    Nguyen, Diem; Castagneyrol, Bastien; Bruelheide, Helge; Bussotti, Filippo; Guyot, Virginie; Jactel, Hervé; Jaroszewicz, Bogdan; Valladares, Fernando; Stenlid, Jan; Boberg, Johanna

    2016-04-01

    European forests host a diversity of tree species that are increasingly threatened by fungal pathogens, which may have cascading consequences for forest ecosystems and their functioning. Previous experimental studies suggest that foliar and root pathogen abundance and disease severity decrease with increasing tree species diversity, but evidences from natural forests are rare. Here, we tested whether foliar fungal disease incidence was negatively affected by tree species diversity in different forest types across Europe. We measured the foliar fungal disease incidence on 16 different tree species in 209 plots in six European countries, representing a forest-type gradient from the Mediterranean to boreal forests. Forest plots of single species (monoculture plots) and those with different combinations of two to five tree species (mixed species plots) were compared. Specifically, we analyzed the influence of tree species richness, functional type (conifer vs. broadleaved) and phylogenetic diversity on overall fungal disease incidence. The effect of tree species richness on disease incidence varied with latitude and functional type. Disease incidence tended to increase with tree diversity, in particular in northern latitudes. Disease incidence decreased with tree species richness in conifers, but not in broadleaved trees. However, for specific damage symptoms, no tree species richness effects were observed. Although the patterns were weak, susceptibility of forests to disease appears to depend on the forest site and tree type.

  8. Positive interactions between herbivores and plant diversity shape forest regeneration.

    Science.gov (United States)

    Cook-Patton, Susan C; LaForgia, Marina; Parker, John D

    2014-05-22

    The effects of herbivores and diversity on plant communities have been studied separately but rarely in combination. We conducted two concurrent experiments over 3 years to examine how tree seedling diversity, density and herbivory affected forest regeneration. One experiment factorially manipulated plant diversity (one versus 15 species) and the presence/absence of deer (Odocoileus virginianus). We found that mixtures outperformed monocultures only in the presence of deer. Selective browsing on competitive dominants and associational protection from less palatable species appear responsible for this herbivore-driven diversity effect. The other experiment manipulated monospecific plant density and found little evidence for negative density dependence. Combined, these experiments suggest that the higher performance in mixture was owing to the acquisition of positive interspecific interactions rather than the loss of negative intraspecific interactions. Overall, we emphasize that realistic predictions about the consequences of changing biodiversity will require a deeper understanding of the interaction between plant diversity and higher trophic levels. If we had manipulated only plant diversity, we would have missed an important positive interaction across trophic levels: diverse seedling communities better resist herbivores, and herbivores help to maintain seedling diversity.

  9. Distribution and diversity of climbing plants in temperate East Asia

    OpenAIRE

    Liang Hu

    2011-01-01

    The composition and geographic distribution of climbing plants are important aspects of ecological study, but research on temperate climbing plants is relatively limited. We compared the family and genera- level composition, floristic element type, growth forms, diversity and geographical distribution of climbing plants in nine districts of temperate East Asia, including Northeast China, Japan, Mongolia and the Korean Peninsula. A total of 304 climbing plant species were documented, belonging...

  10. Probiotic Diversity Enhances Rhizosphere Microbiome Function and Plant Disease Suppression

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    Jie Hu

    2016-12-01

    Full Text Available Bacterial communities associated with plant roots play an important role in the suppression of soil-borne pathogens, and multispecies probiotic consortia may enhance disease suppression efficacy. Here we introduced defined Pseudomonas species consortia into naturally complex microbial communities and measured the importance of Pseudomonas community diversity for their survival and the suppression of the bacterial plant pathogen Ralstonia solanacearum in the tomato rhizosphere microbiome. The survival of introduced Pseudomonas consortia increased with increasing diversity. Further, high Pseudomonas diversity reduced pathogen density in the rhizosphere and decreased the disease incidence due to both intensified resource competition and interference with the pathogen. These results provide novel mechanistic insights into elevated pathogen suppression by diverse probiotic consortia in naturally diverse plant rhizospheres. Ecologically based community assembly rules could thus play a key role in engineering functionally reliable microbiome applications.

  11. Benefits of increasing plant diversity in sustainable agroecosystems

    Science.gov (United States)

    Recent studies have revealed many potential benefits of increasing plant diversity in agroecosystems and production forests, including enhancing yields of crops, forage, and wood; stabilizing yields across time and space; enhancing pollinators and pollination; suppressing weeds and other pests; and ...

  12. Faster speciation and reduced extinction in the tropics contribute to the Mammalian latitudinal diversity gradient.

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    Jonathan Rolland

    2014-01-01

    Full Text Available The increase in species richness from the poles to the tropics, referred to as the latitudinal diversity gradient, is one of the most ubiquitous biodiversity patterns in the natural world. Although understanding how rates of speciation and extinction vary with latitude is central to explaining this pattern, such analyses have been impeded by the difficulty of estimating diversification rates associated with specific geographic locations. Here, we use a powerful phylogenetic approach and a nearly complete phylogeny of mammals to estimate speciation, extinction, and dispersal rates associated with the tropical and temperate biomes. Overall, speciation rates are higher, and extinction rates lower, in the tropics than in temperate regions. The diversity of the eight most species-rich mammalian orders (covering 92% of all mammals peaks in the tropics, except that of the Lagomorpha (hares, rabbits, and pikas reaching a maxima in northern-temperate regions. Latitudinal patterns in diversification rates are strikingly consistent with these diversity patterns, with peaks in species richness associated with low extinction rates (Primates and Lagomorpha, high speciation rates (Diprotodontia, Artiodactyla, and Soricomorpha, or both (Chiroptera and Rodentia. Rates of range expansion were typically higher from the tropics to the temperate regions than in the other direction, supporting the "out of the tropics" hypothesis whereby species originate in the tropics and disperse into higher latitudes. Overall, these results suggest that differences in diversification rates have played a major role in shaping the modern latitudinal diversity gradient in mammals, and illustrate the usefulness of recently developed phylogenetic approaches for understanding this famous yet mysterious pattern.

  13. Plant diversity in the homegardens of Karwar, Karnataka, India

    OpenAIRE

    SHIVANAND BHAT; M. JAYAKARA BHANDARY; L. Rajanna

    2014-01-01

    Bhat S, Bhandary MJ, Rajanna L. 2014. Plant diversity in the homegardens of Karwar, Karnataka, India. Biodiversitas 15: 229-235. A study was conducted in 50 selected home gardens of Karwar, Karnataka, India to document their floristic diversity and composition with regard to life forms and uses. As many as 210 species of flowering plants belonging to 69 families were recorded. Euphorbiaceae (13species), Apocynaceae (11spp.), Cucurbitaceae (10 spp.) and Fabaceae (10 spp.) are the predominant f...

  14. Ant (Hymenoptera, Formicidae) diversity along a pollution gradient near the Middle Ural Copper Smelter, Russia.

    Science.gov (United States)

    Belskaya, Elena; Gilev, Alexey; Belskii, Eugen

    2017-04-01

    Ants are considered to be suitable indicators of ecological change and are widely used in land management and environmental monitoring. However, responses of ant communities to industrial pollution are less known so far. We studied pollution-related variations of ant diversity and abundance near the Middle Ural Copper Smelter (Russia) in 2009 and 2013, with pitfall traps set up at 10 sites in Picea obovata and Abies sibirica forest. This study provided evidences for humped pollution-induced dynamics of ant diversity and abundance. Species richness and diversity peaked in the habitat intermediate between slightly damaged and fully destroyed forest ecosystems. The total abundance of ants peaked in the middle of the pollution gradient and was determined mainly by the dominant species Formica aquilonia. The abundance of other species increased towards the smelter, but was less important for total abundance than that of red wood ants. Community dominants changed with increase of exposure; F. aquilonia, a typical species of mature forests, was replaced by species of open habitats, Lasius niger and Myrmica ruginodis. Habitat variables and competition between species seem to affect local ant communities more strongly than pollution exposure. Stand basal area and cover of the field layer were the main determinants of ant diversity and abundance of individual species.

  15. Mushroom biomass and diversity are driven by different spatio-temporal scales along Mediterranean elevation gradients

    Science.gov (United States)

    Alday, Josu G.; Martínez de Aragón, Juan; de-Miguel, Sergio; Bonet, José Antonio

    2017-04-01

    Mushrooms are important non-wood-forest-products in many Mediterranean ecosystems, being highly vulnerable to climate change. However, the ecological scales of variation of mushroom productivity and diversity, and climate dependence has been usually overlooked due to a lack of available data. We determined the spatio-temporal variability of epigeous sporocarps and the climatic factors driving their fruiting to plan future sustainable management of wild mushrooms production. We collected fruiting bodies in Pinus sylvestris stands along an elevation gradient for 8 consecutive years. Overall, sporocarp biomass was mainly dependent on inter-annual variations, whereas richness was more spatial-scale dependent. Elevation was not significant, but there were clear elevational differences in biomass and richness patterns between ectomycorrhizal and saprotrophic guilds. The main driver of variation was late-summer-early-autumn precipitation. Thus, different scale processes (inter-annual vs. spatial-scale) drive sporocarp biomass and diversity patterns; temporal effects for biomass and ectomycorrhizal fungi vs. spatial scale for diversity and saprotrophic fungi. The significant role of precipitation across fungal guilds and spatio-temporal scales indicates that it is a limiting resource controlling sporocarp production and diversity in Mediterranean regions. The high spatial and temporal variability of mushrooms emphasize the need for long-term datasets of multiple spatial points to effectively characterize fungal fruiting patterns.

  16. Coevolution can explain defensive secondary metabolite diversity in plants.

    Science.gov (United States)

    Speed, Michael P; Fenton, Andy; Jones, Meriel G; Ruxton, Graeme D; Brockhurst, Michael A

    2015-12-01

    Many plant species produce defensive compounds that are often highly diverse within and between populations. The genetic and cellular mechanisms by which metabolite diversity is produced are increasingly understood, but the evolutionary explanations for persistent diversification in plant secondary metabolites have received less attention. Here we consider the role of plant-herbivore coevolution in the maintenance and characteristics of diversity in plant secondary metabolites. We present a simple model in which plants can evolve to invest in a range of defensive toxins, and herbivores can evolve resistance to these toxins. We allow either single-species evolution or reciprocal coevolution. Our model shows that coevolution maintains toxin diversity within populations. Furthermore, there is a fundamental coevolutionary asymmetry between plants and their herbivores, because herbivores must resist all plant toxins, whereas plants need to challenge and nullify only one resistance trait. As a consequence, average plant fitness increases and insect fitness decreases as number of toxins increases. When costs apply, the model showed both arms race escalation and strong coevolutionary fluctuation in toxin concentrations across time. We discuss the results in the context of other evolutionary explanations for secondary metabolite diversification.

  17. Management intensity and topography determined plant diversity in vineyards.

    Directory of Open Access Journals (Sweden)

    Juri Nascimbene

    Full Text Available Vineyards are amongst the most intensive forms of agriculture often resulting in simplified landscapes where semi-natural vegetation is restricted to small scattered patches. However, a tendency toward a more sustainable management is stimulating research on biodiversity in these poorly investigated agro-ecosystems. The main aim of this study was to test the effect on plant diversity of management intensity and topography in vineyards located in a homogenous intensive hilly landscape. Specifically, this study evaluated the role of slope, mowing and herbicide treatments frequency, and nitrogen supply in shaping plant diversity and composition of life-history traits. The study was carried out in 25 vineyards located in the area of the Conegliano-Valdobbiadene DOCG (Veneto, NE Italy. In each vineyard, 10 plots were placed and the abundance of all vascular plants was recorded in each plot. Linear multiple regression was used to test the effect of management and topography on plant diversity. Management intensity and topography were both relevant drivers of plant species diversity patterns in our vineyards. The two most important factors were slope and mowing frequency that respectively yielded positive and negative effects on plant diversity. A significant interaction between these two factors was also demonstrated, warning against the detrimental effects of increasing mowing intensity on steep slope where plant communities are more diverse. The response of plant communities to mowing frequency is mediated by a process of selection of resistant growth forms, such in the case of rosulate and reptant species. The other two management-related factors tested in this study, number of herbicide treatments and N fertilization, were less influential. In general, our study corroborates the idea that some simple changes in farming activities, which are compatible with grape production, should be encouraged for improving the natural and cultural value of the

  18. Management intensity and topography determined plant diversity in vineyards.

    Science.gov (United States)

    Nascimbene, Juri; Marini, Lorenzo; Ivan, Diego; Zottini, Michela

    2013-01-01

    Vineyards are amongst the most intensive forms of agriculture often resulting in simplified landscapes where semi-natural vegetation is restricted to small scattered patches. However, a tendency toward a more sustainable management is stimulating research on biodiversity in these poorly investigated agro-ecosystems. The main aim of this study was to test the effect on plant diversity of management intensity and topography in vineyards located in a homogenous intensive hilly landscape. Specifically, this study evaluated the role of slope, mowing and herbicide treatments frequency, and nitrogen supply in shaping plant diversity and composition of life-history traits. The study was carried out in 25 vineyards located in the area of the Conegliano-Valdobbiadene DOCG (Veneto, NE Italy). In each vineyard, 10 plots were placed and the abundance of all vascular plants was recorded in each plot. Linear multiple regression was used to test the effect of management and topography on plant diversity. Management intensity and topography were both relevant drivers of plant species diversity patterns in our vineyards. The two most important factors were slope and mowing frequency that respectively yielded positive and negative effects on plant diversity. A significant interaction between these two factors was also demonstrated, warning against the detrimental effects of increasing mowing intensity on steep slope where plant communities are more diverse. The response of plant communities to mowing frequency is mediated by a process of selection of resistant growth forms, such in the case of rosulate and reptant species. The other two management-related factors tested in this study, number of herbicide treatments and N fertilization, were less influential. In general, our study corroborates the idea that some simple changes in farming activities, which are compatible with grape production, should be encouraged for improving the natural and cultural value of the landscape by

  19. Bat and bird diversity along independent gradients of latitude and tree composition in European forests.

    Science.gov (United States)

    Charbonnier, Yohan M; Barbaro, Luc; Barnagaud, Jean-Yves; Ampoorter, Evy; Nezan, Julien; Verheyen, Kris; Jactel, Hervé

    2016-10-01

    Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.

  20. Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

    Directory of Open Access Journals (Sweden)

    Loïc ePellissier

    2013-12-01

    Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

  1. Convergence of terrestrial plant production across global climate gradients.

    Science.gov (United States)

    Michaletz, Sean T; Cheng, Dongliang; Kerkhoff, Andrew J; Enquist, Brian J

    2014-08-07

    Variation in terrestrial net primary production (NPP) with climate is thought to originate from a direct influence of temperature and precipitation on plant metabolism. However, variation in NPP may also result from an indirect influence of climate by means of plant age, stand biomass, growing season length and local adaptation. To identify the relative importance of direct and indirect climate effects, we extend metabolic scaling theory to link hypothesized climate influences with NPP, and assess hypothesized relationships using a global compilation of ecosystem woody plant biomass and production data. Notably, age and biomass explained most of the variation in production whereas temperature and precipitation explained almost none, suggesting that climate indirectly (not directly) influences production. Furthermore, our theory shows that variation in NPP is characterized by a common scaling relationship, suggesting that global change models can incorporate the mechanisms governing this relationship to improve predictions of future ecosystem function.

  2. Mobilization of interactions between functional diversity of plant and soil organisms on nitrogen availability and use

    Science.gov (United States)

    Drut, Baptiste; Cassagne, Nathalie; Cannavacciuolo, Mario; Brauman, Alain; Le Floch, Gaëtan; Cobo, Jose; Fustec, Joëlle

    2017-04-01

    Keywords: legumes, earthworms, microorganisms, nitrogen, interactions Both aboveground and belowground biodiversity and their interactions can play an important role in crop productivity. Plant functional diversity, such as legume based intercrops have been shown to improve yields through plant complementarity for nitrogen use (Corre-Hellou et al., 2006). Moreover, plant species or plant genotype may influence the structure of soil microorganism communities through the composition of rhizodeposits in the rhizosphere (Dennis et al., 2010). Belowground diversity can also positively influence plant performance especially related to functional dissimilarity between soil organisms (Eisenhauer, 2012). Earthworms through their burrowing activity influence soil microbial decomposers and nutrient availability and have thus been reported to increase plant growth (Brown, 1995; Brown et al., 2004). We hypothesize that i) plant functional (genetic and/or specific) diversity associated to functional earthworms diversity are key drivers of interactions balance to improve crop performances and ii) the improvement of plant performances can be related to change in the structure of soil microorganism communities due to the diversity of rhizodeposits and the burrowing activity of earthworms. In a first mesocosm experiment, we investigated the effect of a gradient of plant diversity - one cultivar of wheat (Triticum aestivum L.), 3 different wheat cultivars, and 3 different cultivars intercropped with clover (Trifolium hybridum L.) - and the presence of one (endogeic) or two (endogeic and anecic) categories of earthworms on biomass and nitrogen accumulation of wheat. In a second mesocosm experiment, we investigated the influence of three species with different rhizodeposition - wheat, rapeseed (Brassica napus L. ) and faba bean (Vicia faba L.) in pure stand or intercropped - and the presence of endogeic earthworms on microbial activity and nitrogen availability. In the first experiment

  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. Relationship between Soil Properties and Plant Diversity in Semiarid Grassland

    Directory of Open Access Journals (Sweden)

    Melda Dölarslan

    2017-07-01

    Full Text Available In ecological studies, soil-plant interaction is an important environmental factor. Soil chemical and physical properties affect plant richness and diversity. This study was carried out to investigate the relationship between soil physical and chemical properties, and plant diversity indexes (Shannon-Weiner and Simpson in semiarid grassland. Plant diversity indexes and soil properties were determined using 34 quadrats (5x5m on different parent materials (chrome, marble, serpentine, red chalk and red chalk mostra in semiarid grasslands in the Central Anatolia Region in Turkey. Plant samples were collected and recorded periodically from April to September (the vegetation period in 2014 for each quadrat. In order to determine the plant richness and diversity indexes, 3 sub-quadrats (1x1m were randomly added into each of 34 (5x5 m quadrats. To evaluate the relationship between plant diversity indexes and soil properties, composite soil samples were collected from the four corners, and the center of each quadrat 0-30 cm in depth, and which was mixing of those subsamples. Soil sand-silt-clay contents, soil reaction (pH, bulk density (BD, electrical conductivity (EC, CaCO3 and soil organic matter (SOM contents were measured. Relationship between plant diversity indexes measured in different months during vegetation period and soil properties of different parent material was statistically analysed using correlation analysis in SPSS 20.0. Modest correlation coefficient was found between the Simpson diversity index and SOM content, sand-silt-clay content, pH and EC for different months in vegetation period.

  5. Forest climbing plants of West Africa: diversity, ecology and management

    NARCIS (Netherlands)

    Bongers, F.J.J.M.; Parren, M.P.E.; Traoré, D.

    2005-01-01

    Climbing plants, including lianas, represent a fascinating component of the ecology of tropical forests. This book focuses on the climbing plants of West African forests. Based on original research, it presents information on the flora (including a checklist), diversity (with overviews at several le

  6. Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    Andrey Voronkov

    2013-04-01

    Full Text Available A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the total number of identified species was 360. Of these, 47 species are new for Svalbard waters. Bryozoa was the most diverse group. Biogeographic composition revealed features of both Arctic and sub-Arctic properties of the fauna. Species richness, frequency of species occurrence, mean abundance and biomass generally decreased towards the tidal glaciers in inner Kongsfjorden. Among eight environmental factors, depth was most important for explaining variance in the composition of the zoobenthos. The diversity was consistently low at shallow depths, whereas the non-linear patterns of species composition of deeper samples indicated a transitional zone between surface and deeper water masses at 15–20 m depth. Groups of “colonial” and “non-colonial” species differed in diversity, biogeographic composition and distribution by location and depth as well as in relation to other environmental factors. “Non-colonial” species made a greater contribution than “colonial” species to total species richness, total occurrence and biomass in samples, and were more influenced by the depth gradient. Biogeographic composition was sensitive to variation of zoobenthic characteristics over the studied depth range. A list of recorded species and a description of sampling sites are presented.

  7. Stratified Bacterial Diversity along Physico-chemical Gradients in High-Altitude Modern Stromatolites

    Science.gov (United States)

    Toneatti, Diego M.; Albarracín, Virginia H.; Flores, Maria R.; Polerecky, Lubos; Farías, María E.

    2017-01-01

    At an altitude of 3,570 m, the volcanic lake Socompa in the Argentinean Andes is presently the highest site where actively forming stromatolite-like structures have been reported. Interestingly, pigment and microsensor analyses performed through the different layers of the stromatolites (50 mm-deep) showed steep vertical gradients of light and oxygen, hydrogen sulfide and pH in the porewater. Given the relatively good characterization of these physico-chemical gradients, the aim of this follow-up work was to specifically address how the bacterial diversity stratified along the top six layers of the stromatolites which seems the most metabolically important and diversified zone of the whole microbial community. We herein discussed how, in only 7 mm, a drastic succession of metabolic adaptations occurred: i.e., microbial communities shift from a UV-high/oxic world to an IR-low/anoxic/high H2S environment which force stratification and metabolic specialization of the bacterial community, thus, modulating the chemical faces of the Socompa stromatolites. The oxic zone was dominated by Deinococcus sp. at top surface (0.3 mm), followed by a second layer of Coleofasciculus sp. (0.3 to ∼2 mm). Sequences from anoxygenic phototrophic Alphaproteobacteria, along with an increasing diversity of phyla including Bacteroidetes, Spirochaetes were found at middle layers 3 and 4. Deeper layers (5–7 mm) were mostly occupied by sulfate reducers of Deltaproteobacteria, Bacteroidetes and Firmicutes, next to a high diversity and equitable community of rare, unclassified and candidate phyla. This analysis showed how microbial communities stratified in a physicochemical vertical profile and according to the light source. It also gives an insight of which bacterial metabolic capabilities might operate and produce a microbial cooperative strategy to thrive in one of the most extreme environments on Earth. PMID:28446906

  8. Diversity and bioprospecting of actinomycete endophytes from the medicinal plants.

    Science.gov (United States)

    Nalini, M S; Prakash, H S

    2017-04-01

    The endophytic actinomycetes constitute one of the fascinating group of microorganisms associated with a wide range of plant species. The diversity of actinomycetes in plants and their tissue parts is a matter of debate as no consensus are derived between individual studies. Nevertheless, their diversity correlates with the occurrence in plant species harboured in unique regions of biologically diverse areas called "hot spots." Recent advances in the isolation techniques have facilitated the isolation of rare taxa from these environments. The biosynthetic ability of the endophytic actinomycetes has proven beyond doubt that these organisms have the potential to synthesize an array of compounds with novelty in structure and bioactivity and as a result are preferred in the natural product screening programs. In the years to come, the scientific world may await to discover many more novel actinomycete taxa with metabolic diversity and applications in therapeutics.

  9. Carbon storage potential by four macrophytes as affected by planting diversity in a created wetland.

    Science.gov (United States)

    Means, Mary M; Ahn, Changwoo; Korol, Alicia R; Williams, Lisa D

    2016-01-01

    Wetland creation has become a commonplace method for mitigating the loss of natural wetlands. Often mitigation projects fail to restore ecosystem services of the impacted natural wetlands. One of the key ecosystem services of newly created wetlands is carbon accumulation/sequestration, but little is known about how planting diversity (PD) affects the ability of herbaceous wetland plants to store carbon in newly created wetlands. Most mitigation projects involve a planting regime, but PD, which may be critical in establishing biologically diverse and ecologically functioning wetlands, is seldom required. Using a set of 34 mesocosms (∼1 m(2) each), we investigated the effects of planting diversity on carbon storage potential of four native wetland plant species that are commonly planted in created mitigation wetlands in Virginia - Carex vulpinoidea, Eleocharis obtusa, Juncus effusus, and Mimulus ringens. The plants were grown under the four distinctive PD treatments [i.e., monoculture (PD 1) through four different species mixture (PD 4)]. Plant biomass was harvested after two growing seasons and analyzed for tissue carbon content. Competition values (CV) were calculated to understand how the PD treatment affected the competitive ability of plants relative to their biomass production and thus carbon storage potentials. Aboveground biomass ranged from 988 g/m(2) - 1515 g/m(2), being greatest in monocultures, but only when compared to the most diverse mixture (p = 0.021). However, carbon storage potential estimates per mesocosm ranged between 344 g C/m(2) in the most diverse mesocosms (PD 4) to 610 g C/m(2) in monoculture ones with no significant difference (p = 0.089). CV of E. obtusa and C. vulpinoidea showed a declining trend when grown in the most diverse mixtures but J. effusus and M. ringens displayed no difference across the PD gradient (p = 0.910). In monocultures, both M. ringens, and J. effusus appeared to store carbon as biomass more

  10. Forest structure, diversity and regeneration potential along altitudinal gradient in Dhanaulti of Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Sushil Saha

    2016-07-01

    Full Text Available Aim of the study: The aim of the present study was to understatnd the forest composition, structure, diversity and regeneration potential along altitudinal gradient. Area of study: The study was carried out in Dhanaulti forest which falls under temperate region of Garhwal Himalaya in Uttarakhand state, India. Material and Methods: Vegetation analysis was carried out using 10 quadrats at each altitude using a quadrate size of 10×10 m2. In each quadrate, categories of trees >30 cm cbh were considered as trees, 10-30cm cbh as saplings and <10 cm cbh as seedlings. The data were quantitatively analyzed. Main results: In upper and middle altitudes, Cedrus deodara was reported dominant tree whereas, in lower altitude Quercus leucotrichophora was reported dominant. Tree density was highest in lower altitude which reduced middle and upper altitudes whereas, total basal cover increased with increasing altitude. The increasing total basal cover with altitude could be because of the presence of Cedrus deodara trees having higher girth classes. In tree, sapling and seedling layers, diversity (H and equitabiltiy (EC decreased with increasing altitude. However, concentrations of dominace (CD and beta diversity (BD have shown reverse trend with H and EC which increased with increasing altitudes, in each layer of tree, sapling and seedling. The distribution pattern of most species in all layers of trees, saplings and seedlings was contagious. The regeneration potential of the species has shown that some of the species in the absence of tree layer are still regenerating particularly, Rhododendron arboreum, Benthamidia capitata, Neolitsea pallens etc. It indicates that most of the species are shifting upward as they are getting suitable conditions. Research highlights: Altitude influence species composition, diversity and regeneration potential of species. Key words: Distribution pattern; tree diversity; regeneration; mountains; temperate; Himalaya.

  11. Ocean thermal gradient as a generator of electricity. OTEC power plant

    Science.gov (United States)

    Enrique, Luna-Gomez Victor; Angel, Alatorre-Mendieta Miguel

    2016-04-01

    The OTEC (Ocean Thermal Energy Conversion) is a power plant that uses the thermal gradient of the sea water between the surface and a depth of about 700 meters. It works by supplying the heat to a steam machine, for evaporation, with sea water from the surface and cold, to condense the steam, with deep sea water. The energy generated by the power plant OTEC can be transferred to the electric power grid, another use is to desalinate seawater. During the twentieth century in some countries experimental power plants to produce electricity or obtaining drinking water they were installed. On the Mexico's coast itself this thermal gradient, as it is located in tropical seas it occurs, so it has possibilities of installing OTEC power plant type. In this paper one type OTEC power plant operation is represented in most of its components.

  12. Severe plant invasions can increase mycorrhizal fungal abundance and diversity

    DEFF Research Database (Denmark)

    Lekberg, Ylva; Gibbons, Sean; Rosendahl, Søren;

    2013-01-01

    Invasions by non-native plants can alter ecosystem functions and reduce native plant diversity, but relatively little is known about their effect on belowground microbial communities. We show that invasions by knapweed (Centaurea stoebe) and leafy spurge (Euphorbia esula, hereafter spurge)-but no...... plant provenance.The ISME Journal advance online publication, 14 March 2013; doi:10.1038/ismej.2013.41....

  13. Intertidal epilithic bacteria diversity changes along a naturally occurring carbon dioxide and pH gradient.

    Science.gov (United States)

    Taylor, Joe D; Ellis, Rebecca; Milazzo, Marco; Hall-Spencer, Jason M; Cunliffe, Michael

    2014-09-01

    Intertidal epilithic bacteria communities are important components of coastal ecosystems, yet few studies have assessed their diversity and how it may be affected by changing environmental parameters. Submarine CO2 seeps produce localised areas of CO2-enriched seawater with reduced pH levels. We utilised the seawater pH/CO2 gradient at Levante Bay (Italy) to test the hypothesis that epilithic bacteria communities are modified by exposure to seawater with the varying chemical parameters. Biofilms were sampled from three sites exposed to seawater with different pH/CO2 levels and diversity determined using high-throughput sequencing of 16S rRNA genes. Seawater pCO2 concentrations were increased from ambient at site 1 to 621 μatm at site 2 and 1654 μatm site 3, similar to the predicated future oceans beyond 2050 and 2150, respectively. Alpha diversity of total bacteria communities and Cyanobacteria communities was significantly different between sites (anova P ocean acidification on coastal marine ecosystems.

  14. Trophic state and geographic gradients influence planktonic cyanobacterial diversity and distribution in New Zealand lakes.

    Science.gov (United States)

    Wood, Susanna A; Maier, Marcia Y; Puddick, Jonathan; Pochon, Xavier; Zaiko, Anastasija; Dietrich, Daniel R; Hamilton, David P

    2017-02-01

    Cyanobacteria are commonly associated with eutrophic lakes, where they often form blooms and produce toxins. However, they are a ubiquitous component of phytoplankton in lakes of widely varying trophic status. We hypothesised that cyanobacterial diversity would vary among lakes of differing trophic status, but that the relative importance of geographical and hydromorphological characteristics driving these patterns would differ across trophic groups. DNA from 143 New Zealand lakes that spanned a range of geographic, hydromorphological and trophic gradients was analysed using automated rRNA intergenic spacer analysis and screened for genes involved in cyanotoxin production. Statistical analysis revealed significant delineation among cyanobacterial communities from different trophic classes. Multivariate regression indicated that geographical features (latitude, longitude and altitude) were significant in driving cyanobacterial community structure; however, partitioning of their effects varied among trophic categories. High-throughput sequencing was undertaken on selected samples to investigate their taxonomic composition. The most abundant and diverse (71 operational taxonomic units) taxon across all lake types was the picocyanobacteria genus Synechococcus Cyanotoxins (microcystins n = 23, anatoxins n = 1) were only detected in eutrophic lowland lakes. Collectively, these data infer that increasing eutrophication of lakes will have broad-scale impacts on planktonic cyanobacteria diversity and the prevalence of cyanotoxins. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Diversity of pico- to mesoplankton along the 2000 km salinity gradient of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Yue O.O. Hu

    2016-05-01

    Full Text Available Microbial plankton form the productive base of both marine and freshwater ecosystems and are key drivers of global biogeochemical cycles of carbon and nutrients. Plankton diversity is immense with representations from all major phyla within the three domains of life. So far, plankton monitoring has mainly been based on microscopic identification, which has limited sensitivity and reproducibility, not least because of the numerical majority of plankton being unidentifiable under the light microscope. High-throughput sequencing of taxonomic marker genes offers a means to identify taxa inaccessible by traditional methods; thus, recent studies have unveiled an extensive previously unknown diversity of plankton. Here, we conducted ultra-deep Illumina sequencing (average 105 sequences/sample of rRNA gene amplicons of surface water eukaryotic and bacterial plankton communities sampled in summer along a 2000 km transect following the salinity gradient of the Baltic Sea. Community composition was strongly correlated with salinity for both bacterial and eukaryotic plankton assemblages, highlighting the importance of salinity for structuring the biodiversity within this ecosystem. In contrast, no clear trends in alpha-diversity for bacterial or eukaryotic communities could be detected along the transect. The distribution of major planktonic taxa followed expected patterns as observed in monitoring programs, but groups novel to the Baltic Sea were also identified, such as relatives to the coccolithophore Emiliana huxleyi detected in the northern Baltic Sea. This study provides the first ultra-deep sequencing-based survey on eukaryotic and bacterial plankton biogeography in the Baltic Sea.

  16. Diversity of Pico- to Mesoplankton along the 2000 km Salinity Gradient of the Baltic Sea.

    Science.gov (United States)

    Hu, Yue O O; Karlson, Bengt; Charvet, Sophie; Andersson, Anders F

    2016-01-01

    Microbial plankton form the productive base of both marine and freshwater ecosystems and are key drivers of global biogeochemical cycles of carbon and nutrients. Plankton diversity is immense with representations from all major phyla within the three domains of life. So far, plankton monitoring has mainly been based on microscopic identification, which has limited sensitivity and reproducibility, not least because of the numerical majority of plankton being unidentifiable under the light microscope. High-throughput sequencing of taxonomic marker genes offers a means to identify taxa inaccessible by traditional methods; thus, recent studies have unveiled an extensive previously unknown diversity of plankton. Here, we conducted ultra-deep Illumina sequencing (average 10(5) sequences/sample) of rRNA gene amplicons of surface water eukaryotic and bacterial plankton communities sampled in summer along a 2000 km transect following the salinity gradient of the Baltic Sea. Community composition was strongly correlated with salinity for both bacterial and eukaryotic plankton assemblages, highlighting the importance of salinity for structuring the biodiversity within this ecosystem. In contrast, no clear trends in alpha-diversity for bacterial or eukaryotic communities could be detected along the transect. The distribution of major planktonic taxa followed expected patterns as observed in monitoring programs, but groups novel to the Baltic Sea were also identified, such as relatives to the coccolithophore Emiliana huxleyi detected in the northern Baltic Sea. This study provides the first ultra-deep sequencing-based survey on eukaryotic and bacterial plankton biogeography in the Baltic Sea.

  17. Diversity and use of ethnomedicinal plants in coastal Karnataka, India

    Directory of Open Access Journals (Sweden)

    M. JAYAKARA BHANDARY

    2014-04-01

    Full Text Available Bhandary MJ, Chandrashekar KR. 2014. Diversity and use of ethnomedicinal plants in coastal Karnataka, India. Biodiversitas 15: 89-93. A study was undertaken in Coastal Karnataka, a culturally and floristically diverse region between the Western Ghats and the Arabian sea in India, to document the diversity and uses of ethnomedicinal plants of the area. This study resulted in the documentation of ethnomedicinal uses of 342 species of plants belonging to 34 families. The dominant families of ethnomedicinal plants were: Fabaceae (38 species, Euphorbiaceae (22 species, Rubiaceae (11 species, Acanthaceae, Asteraceae, Apocynaceae and Rutaceae (10 species each. Among the plants used, 30% are herbs, 27% trees, 25% climbers and 18% shrubs. Majority of the plants are used against several diseases, either alone or in combination with other plants. The most popular medicinal plants, in terms of the number of diseases against which they are used, are Cyclea peltata, Aristolochia indica, Cuminum cyminum, Curcuma longa, Tamarindus indica, Asparagus racemosus, Ficus racemosa, Hemidesmus indicus, Ficus religiosa, Calotropis gigantea, Vitex negundo, Aegle marmelos and Leucas aspera. A list of 50 important ethnomedicinal plants of the region which are used in the treatment of 5 or more disorders is provided.

  18. Accelerating global access to plant diversity information.

    Science.gov (United States)

    Lughadha, Eimear Nic; Miller, Chuck

    2009-11-01

    Botanic gardens play key roles in the development and dissemination of plant information resources. Drivers for change have included progress in information technology, growing public expectations of electronic access and international conservation policy. Great advances have been made in the quantity, quality and accessibility of plant information in digital form and the extent to which information from multiple providers can be accessed through a single portal. However, significant challenges remain to be addressed in making botanic gardens resources maximally accessible and impactful, not least the overwhelming volume of material which still awaits digitisation. The year 2010 represents an opportunity for botanic gardens to showcase their collaborative achievements in delivery of electronic plant information and reinforce their relevance to pressing environmental issues.

  19. Rhizosphere bacterial communities of dominant steppe plants shift in response to a gradient of simulated nitrogen deposition

    Directory of Open Access Journals (Sweden)

    An eYang

    2015-08-01

    Full Text Available We evaluated effects of 9-year simulation of simulated nitrogen (N deposition on microbial composition and diversity in the rhizosphere of two dominant temperate grassland species: grass Stipa krylovii and forb Artemisia frigida. Microbiomes in S. krylovii and A.frigida rhizosphere differed, but changed consistently along the N gradient. These changes were correlated to N-induced shifts to plant community. Hence, as plant biomass changed, so did bacterial rhizosphere communities, a result consistent with the role that N fertilizer has been shown to play in altering plant-microbial mutualisms. A total of 23 bacterial phyla were detected in the two rhizospheric soils by pyrosequencing, with Proteobacteria, Acidobacteria and Bacteroidetes dominating the sequences of all samples. Bacterioidetes and Proteobacteria tended to increase, while Acidobacteria declined with increase in N addition rates. TM7 increased >5-fold in the high N addition rates, especially in S. krylovii rhizosphere. Nitrogen addition also decreased diversity of OTUs (operational taxonomic units, Shannon and Chao1 indices of rhizospheric microbes regardless of plant species. These results suggest that there were both similar but also specific changes in microbial communities of temperate steppes due to N deposition.

  20. Transgenic tobacco revealing altered bacterial diversity in the rhizosphere during early plant development.

    Science.gov (United States)

    Andreote, Fernando D; Mendes, Rodrigo; Dini-Andreote, Francisco; Rossetto, Priscilla B; Labate, Carlos A; Pizzirani-Kleiner, Aline A; van Elsas, Jan Dirck; Azevedo, João L; Araújo, Welington L

    2008-05-01

    The rhizosphere constitutes a complex niche that may be exploited by a wide variety of bacteria. Bacterium-plant interactions in this niche can be influenced by factors such as the expression of heterologous genes in the plant. The objective of this work was to describe the bacterial communities associated with the rhizosphere and rhizoplane regions of tobacco plants, and to compare communities from transgenic tobacco lines (CAB1, CAB2 and TRP) with those found in wild-type (WT) plants. Samples were collected at two stages of plant development, the vegetative and flowering stages (1 and 3 months after germination). The diversity of the culturable microbial community was assessed by isolation and further characterization of isolates by amplified ribosomal RNA gene restriction analysis (ARDRA) and 16S rRNA sequencing. These analyses revealed the presence of fairly common rhizosphere organisms with the main groups Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Bacilli. Analysis of the total bacterial communities using PCR-DGGE (denaturing gradient gel electrophoresis) revealed that shifts in bacterial communities occurred during early plant development, but the reestablishment of original community structure was observed over time. The effects were smaller in rhizosphere than in rhizoplane samples, where selection of specific bacterial groups by the different plant lines was demonstrated. Clustering patterns and principal components analysis (PCA) were used to distinguish the plant lines according to the fingerprint of their associated bacterial communities. Bands differentially detected in plant lines were found to be affiliated with the genera Pantoea, Bacillus and Burkholderia in WT, CAB and TRP plants, respectively. The data revealed that, although rhizosphere/rhizoplane microbial communities can be affected by the cultivation of transgenic plants, soil resilience may be able to restore the original bacterial diversity after one cycle of plant

  1. Late Cenozoic onset of the latitudinal diversity gradient of North American mammals

    Science.gov (United States)

    Marcot, Jonathan D.; Fox, David L.; Niebuhr, Spencer R.

    2016-06-01

    The decline of species richness from equator to pole, or latitudinal diversity gradient (LDG), is nearly universal among clades of living organisms, yet whether it was such a pervasive pattern in the geologic past remains uncertain. Here, we calculate the strength of the LDG for terrestrial mammals in North America over the past 65 My, using 27,903 fossil occurrences of Cenozoic terrestrial mammals from western North America downloaded from the Paleobiology Database. Accounting for temporal and spatial variation in sampling, the LDG was substantially weaker than it is today for most of the Cenozoic and the robust modern LDG of North American mammals evolved only over the last 4 My. The strength of the LDG correlates negatively with global temperature, suggesting a role of global climate patterns in the establishment and maintenance of the LDG for North American mammals.

  2. Forest structure, diversity and regeneration potential along altitudinal gradient in Dhanaulti of Garhwal Himalaya

    Energy Technology Data Exchange (ETDEWEB)

    Saha, S.; Rajwar, G.S.; Kumar, M.

    2016-07-01

    Aim of the study: The aim of the present study was to understatnd the forest composition, structure, diversity and regeneration potential along altitudinal gradient. Area of study: The study was carried out in Dhanaulti forest which falls under temperate region of Garhwal Himalaya in Uttarakhand state, India. Material and Methods: Vegetation analysis was carried out using 10 quadrats at each altitude using a quadrate size of 10×10 m2. In each quadrate, categories of trees >30 cm cbh were considered as trees, 10-30cm cbh as saplings and <10 cm cbh as seedlings. The data were quantitatively analyzed. Main results: In upper and middle altitudes, Cedrus deodara was reported dominant tree whereas, in lower altitude Quercus leucotrichophora was reported dominant. Tree density was highest in lower altitude which reduced middle and upper altitudes whereas, total basal cover increased with increasing altitude. The increasing total basal cover with altitude could be because of the presence of Cedrus deodara trees having higher girth classes. In tree, sapling and seedling layers, diversity (H) and equitabiltiy (EC) decreased with increasing altitude. However, concentrations of dominace (CD) and beta diversity (BD have shown reverse trend with H and EC which increased with increasing altitudes, in each layer of tree, sapling and seedling. The distribution pattern of most species in all layers of trees, saplings and seedlings was contagious. The regeneration potential of the species has shown that some of the species in the absence of tree layer are still regenerating particularly, Rhododendron arboreum, Benthamidia capitata, Neolitsea pallens etc. It indicates that most of the species are shifting upward as they are getting suitable conditions. Research highlights: Altitude influence species composition, diversity and regeneration potential of species. (Author)

  3. Diversity and Distribution of Freshwater Aerobic Anoxygenic Phototrophic Bacteria across a Wide Latitudinal Gradient

    Science.gov (United States)

    Ferrera, Isabel; Sarmento, Hugo; Priscu, John C.; Chiuchiolo, Amy; González, José M.; Grossart, Hans-Peter

    2017-01-01

    Aerobic anoxygenic phototrophs (AAPs) have been shown to exist in numerous marine and brackish environments where they are hypothesized to play important ecological roles. Despite their potential significance, the study of freshwater AAPs is in its infancy and limited to local investigations. Here, we explore the occurrence, diversity and distribution of AAPs in lakes covering a wide latitudinal gradient: Mongolian and German lakes located in temperate regions of Eurasia, tropical Great East African lakes, and polar permanently ice-covered Antarctic lakes. Our results show a widespread distribution of AAPs in lakes with contrasting environmental conditions and confirm that this group is composed of different members of the Alpha- and Betaproteobacteria. While latitude does not seem to strongly influence AAP abundance, clear patterns of community structure and composition along geographic regions were observed as indicated by a strong macro-geographical signal in the taxonomical composition of AAPs. Overall, our results suggest that the distribution patterns of freshwater AAPs are likely driven by a combination of small-scale environmental conditions (specific of each lake and region) and large-scale geographic factors (climatic regions across a latitudinal gradient). PMID:28275369

  4. Quantifying component diversities along temporal and geographic gradients in Cenozoic circumalpine carbonates

    Science.gov (United States)

    Nebelsick, James; Bassi, Davide; Nitsch, Florian; Grun, Tobias

    2016-04-01

    This study explores the component relationships within indurated carbonates which can dominate sedimentary sequence. The data for the analysis is gained by point counting of numerous thin sections. Resolution of component identification is dependent on various factors including the presence and recognition of taxon specific character in the two dimensions available in thin sections; the microtaphofacies of the environment of deposition and component architectures determine fragmentation, abrasion, encrustation and bioerosion rates as well as diagenetic pathways. The highest taxonomic resolution is reached by coralline algae and larger foraminifera which are indentified using characters derived from thin sections. Multivariate analysis (MDS, Cluster analysis) is used to component distributions within and between facies as well as localities. Component relationships, in part directly deduced within encrustation sequences, are explored using bivariate analysis. Studied thin sections originate from detailed studies of localities both north (Southern Germany, Austria) and south (Northern Italy, Slovenia) and of the Alps. Detailed facies analysis, itself often based on statistical analysis of components, show variations in environmental factors at different scales including local shelf gradients and terrigenous influx, regional paleogeographic developments within the Mediterranean Tethys and Paratethys as well as global climatic change during the Oligocene and crossing into the Miocene. The localities differ in the diversity and abundance of a wide variety of components including coralline algae, smaller and larger benthic foraminifera, corals, bryozoans, barnacles and echinoderms among others. Generic and species identification of both coralline algae and larger foraminiferal taxa allow taxonomic gradients to be established.

  5. Decline in coccolithophore diversity and impact on coccolith morphogenesis along a natural CO2 gradient.

    Science.gov (United States)

    Ziveri, Patrizia; Passaro, Marcello; Incarbona, Alessandro; Milazzo, Marco; Rodolfo-Metalpa, Riccardo; Hall-Spencer, Jason M

    2014-06-01

    A natural pH gradient caused by marine CO2 seeps off Vulcano Island (Italy) was used to assess the effects of ocean acidification on coccolithophores, which are abundant planktonic unicellular calcifiers. Such seeps are used as natural laboratories to study the effects of ocean acidification on marine ecosystems, since they cause long-term changes in seawater carbonate chemistry and pH, exposing the organisms to elevated CO2 concentrations and therefore mimicking future scenarios. Previous work at CO2 seeps has focused exclusively on benthic organisms. Here we show progressive depletion of 27 coccolithophore species, in terms of cell concentrations and diversity, along a calcite saturation gradient from Ωcalcite 6.4 to CO2 seeps had the highest concentrations of malformed Emiliania huxleyi. These observations add to a growing body of evidence that ocean acidification may benefit some algae but will likely cause marine biodiversity loss, especially by impacting calcifying species, which are affected as carbonate saturation falls.

  6. Plant Diversity Surpasses Plant Functional Groups and Plant Productivity as Driver of Soil Biota in the Long Term

    Science.gov (United States)

    Eisenhauer, Nico; Milcu, Alexandru; Sabais, Alexander C. W.; Bessler, Holger; Brenner, Johanna; Engels, Christof; Klarner, Bernhard; Maraun, Mark; Partsch, Stephan; Roscher, Christiane; Schonert, Felix; Temperton, Vicky M.; Thomisch, Karolin; Weigelt, Alexandra; Weisser, Wolfgang W.; Scheu, Stefan

    2011-01-01

    Background One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments. Methodology/Principal Findings We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time. Conclusions/Significance Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning. PMID:21249208

  7. Plant diversity surpasses plant functional groups and plant productivity as driver of soil biota in the long term.

    Directory of Open Access Journals (Sweden)

    Nico Eisenhauer

    Full Text Available BACKGROUND: One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments. METHODOLOGY/PRINCIPAL FINDINGS: We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time. CONCLUSIONS/SIGNIFICANCE: Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning.

  8. Evolution and diversity of green plant cell walls.

    Science.gov (United States)

    Popper, Zoë A

    2008-06-01

    Plant cells are surrounded by a dynamic cell wall that performs many essential biological roles, including regulation of cell expansion, the control of tissue cohesion, ion-exchange and defence against microbes. Recent evidence shows that the suite of polysaccharides and wall proteins from which the plant cell wall is composed shows variation between monophyletic plant taxa. This is likely to have been generated during the evolution of plant groups in response to environmental stress. Understanding the natural variation and diversity that exists between cell walls from different taxa is key to facilitating their future exploitation and manipulation, for example by increasing lignocellulosic content or reducing its recalcitrance for use in biofuel generation.

  9. Herbivores and nutrients control grassland plant diversity via light limitation

    Science.gov (United States)

    Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

    2014-01-01

    Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  10. Environmental change in a Mediterranean salt marsh wetland: ecological drivers of halophytes diversity along flooding frequency gradients

    Directory of Open Access Journals (Sweden)

    Patricia María Rodríguez-González

    2014-04-01

    Full Text Available Coastal wetlands are among most threatened ecosystems, owing to the intense human activity concentrated in shoreline areas together with the expected sea level rise resultant from climate change. Salt marshes are wetlands which are inundated twice daily by the sea, thus tightly dependent on frequency and duration of submergence. Identifying the factors that determine the diversity, distribution and abundance of halophyte species in salt marshes will help retaining their conservation status and adopt anticipate management measures, and this will ultimately contribute to preserve marshland biodiversity and ecological services. Reserva Natural de Castro Marim e Vila Real de Santo António (RNSCMVRSA is a natural reserve located in South Eastern Portugal, comprising the tidal area of Guadiana River mouth. In spite of their great ecological value, salt marsh ecosystems in this region have suffered intense anthropic disturbance, namely hydrologic alterations and vegetation removal to gain soils for agriculture and salt intensive production. The present study aimed at characterizing the halophyte diversity in the RNSCMVRSA salt marshes and determining their major ecological correlates. The end-point is to implement, afterward, a sustainable cultivation of autochthonous halophyte plants, with economic value, in the abandoned saltpans and degraded rangelands. This project will contribute to the conservation of halophyte diversity, promote environmental requalification, and provide an economic alternative for local populations, enabling the reduction of unregulated harvest of halophyte plant populations. Field sampling strategy included a preliminary survey of local vegetation diversity and floristic inventories of halophyte communities in plots established across the existing environmental heterogeneity in order to span the whole variation gradients of the species presence and abundance. The abiotic characterization of halophyte communities included a

  11. The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia's headwaters.

    Science.gov (United States)

    Wang, Xuexia; Dong, Shikui; Yang, Bing; Li, Yuanyuan; Su, Xukun

    2014-10-01

    A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland.

  12. Modeling Forest Structure and Vascular Plant Diversity in Piedmont Forests

    Science.gov (United States)

    Hakkenberg, C.

    2014-12-01

    When the interacting stressors of climate change and land cover/land use change (LCLUC) overwhelm ecosystem resilience to environmental and climatic variability, forest ecosystems are at increased risk of regime shifts and hyperdynamism in process rates. To meet the growing range of novel biotic and environmental stressors on human-impacted ecosystems, the maintenance of taxonomic diversity and functional redundancy in metacommunities has been proposed as a risk spreading measure ensuring that species critical to landscape ecosystem functioning are available for recruitment as local systems respond to novel conditions. This research is the first in a multi-part study to establish a dynamic, predictive model of the spatio-temporal dynamics of vascular plant diversity in North Carolina Piedmont mixed forests using remotely sensed data inputs. While remote sensing technologies are optimally suited to monitor LCLUC over large areas, direct approaches to the remote measurement of plant diversity remain a challenge. This study tests the efficacy of predicting indices of vascular plant diversity using remotely derived measures of forest structural heterogeneity from aerial LiDAR and high spatial resolution broadband optical imagery in addition to derived topo-environmental variables. Diversity distribution modelling of this sort is predicated upon the idea that environmental filtering of dispersing species help define fine-scale (permeable) environmental envelopes within which biotic structural and compositional factors drive competitive interactions that, in addition to background stochasticity, determine fine-scale alpha diversity. Results reveal that over a range of Piedmont forest communities, increasing structural complexity is positively correlated with measures of plant diversity, though the nature of this relationship varies by environmental conditions and community type. The diversity distribution model is parameterized and cross-validated using three high

  13. Trees and the City: Diversity and Composition along a Neotropical Gradient of Urbanization

    Directory of Open Access Journals (Sweden)

    Rubén Ortega-Álvarez

    2011-01-01

    Full Text Available In this study we assessed tree species richness, density, and composition patterns along a gradient of urbanization of a megacity. Our results show that total, native, and exotic tree densities were highest in green areas where larger spaces are considered for greening purposes. Conversely, total, native, and exotic tree species richness were highest in land uses with intermediate levels of urban development (residential, residential-commercial areas. Not finding highest tree species richness in less developed urban areas suggests that cultural factors may shape the array of species that are planted within cities. Supporting this, tree composition analyses showed that green areas are comprised of different tree species when compared to the rest of the studied urban land uses. Thus, our results suggest that, to increase the ecological quality of cities, residents and managers should be encouraged to select a greater variety of trees to promote heterogeneous green areas.

  14. Diversity begets diversity: host expansions and the diversification of plant-feeding insects

    Directory of Open Access Journals (Sweden)

    Nylin Sören

    2006-01-01

    Full Text Available Abstract Background Plant-feeding insects make up a large part of earth's total biodiversity. While it has been shown that herbivory has repeatedly led to increased diversification rates in insects, there has been no compelling explanation for how plant-feeding has promoted speciation rates. There is a growing awareness that ecological factors can lead to rapid diversification and, as one of the most prominent features of most insect-plant interactions, specialization onto a diverse resource has often been assumed to be the main process behind this diversification. However, specialization is mainly a pruning process, and is not able to actually generate diversity by itself. Here we investigate the role of host colonizations in generating insect diversity, by testing if insect speciation rate is correlated with resource diversity. Results By applying a variant of independent contrast analysis, specially tailored for use on questions of species richness (MacroCAIC, we show that species richness is strongly correlated with diversity of host use in the butterfly family Nymphalidae. Furthermore, by comparing the results from reciprocal sister group selection, where sister groups were selected either on the basis of diversity of host use or species richness, we find that it is likely that diversity of host use is driving species richness, rather than vice versa. Conclusion We conclude that resource diversity is correlated with species richness in the Nymphalidae and suggest a scenario based on recurring oscillations between host expansions – the incorporation of new plants into the repertoire – and specialization, as an important driving force behind the diversification of plant-feeding insects.

  15. Vascular plant diversity of the Paracel Islands, China

    Directory of Open Access Journals (Sweden)

    Yi Tong

    2013-05-01

    Full Text Available The Paracel Islands (Xisha Islands comprise a group of tropical islands that are located south of mainland China and have a particular natural flora. Based on a literature search and our own investigations, we present here a checklist of plants for 24 of the Paracel Islands. We also report an analysis of plant diversity, its distribution and relationship with that of neighboring regions. A total of 396 vascular plants were recorded which belonged to 262 genera and 85 families. Of these, 220 were wild species and 176 were cultivated. As a whole, the islands do not possess a rich flora; however, there are major differences in plant diversity among islands. The flora consists in large part of tropical elements, typical of tropical coral islands of China. The flora is most closely connected to that of Hainan Island, and closely related to those of Taiwan of China, Indochina, Malaysia, Indonesia and the Philippines.

  16. Latitudinal diversity gradients in New World bats: are they a consequence of niche conservatism?

    Directory of Open Access Journals (Sweden)

    Maria João Ramos Pereira

    Full Text Available The increase in species diversity from the Poles to the Equator is a major biogeographic pattern, but the mechanisms underlying it remain obscure. Our aim is to contribute to their clarification by describing the latitudinal gradients in species richness and in evolutionary age of species of New World bats, and testing if those patterns may be explained by the niche conservatism hypothesis. Maps of species ranges were used to estimate species richness in a 100 x 100 km grid. Root distances in a molecular phylogeny were used as a proxy for the age of species, and the mean root distance of the species in each cell of the grid was estimated. Generalised additive models were used to relate latitude with both species richness and mean root distance. This was done for each of the three most specious bat families and for all Chiroptera combined. Species richness increases towards the Equator in the whole of the Chiroptera and in the Phyllostomidae and Molossidae, families that radiated in the tropics, but the opposite trend is observed in the Vespertilionidae, which has a presumed temperate origin. In the whole of the Chiroptera, and in the three main families, there were more basal species in the higher latitudes, and more derived species in tropical areas. In general, our results were not consistent with the predictions of niche conservatism. Tropical niche conservatism seems to keep bat clades of tropical origin from colonizing temperate zones, as they lack adaptations to survive cold winters, such as the capacity to hibernate. However, the lower diversity of Vespertilionidae in the Neotropics is better explained by competition with a diverse pre-existing community of bats than by niche conservatism.

  17. Latitudinal diversity gradients in New World bats: are they a consequence of niche conservatism?

    Science.gov (United States)

    Ramos Pereira, Maria João; Palmeirim, Jorge M

    2013-01-01

    The increase in species diversity from the Poles to the Equator is a major biogeographic pattern, but the mechanisms underlying it remain obscure. Our aim is to contribute to their clarification by describing the latitudinal gradients in species richness and in evolutionary age of species of New World bats, and testing if those patterns may be explained by the niche conservatism hypothesis. Maps of species ranges were used to estimate species richness in a 100 x 100 km grid. Root distances in a molecular phylogeny were used as a proxy for the age of species, and the mean root distance of the species in each cell of the grid was estimated. Generalised additive models were used to relate latitude with both species richness and mean root distance. This was done for each of the three most specious bat families and for all Chiroptera combined. Species richness increases towards the Equator in the whole of the Chiroptera and in the Phyllostomidae and Molossidae, families that radiated in the tropics, but the opposite trend is observed in the Vespertilionidae, which has a presumed temperate origin. In the whole of the Chiroptera, and in the three main families, there were more basal species in the higher latitudes, and more derived species in tropical areas. In general, our results were not consistent with the predictions of niche conservatism. Tropical niche conservatism seems to keep bat clades of tropical origin from colonizing temperate zones, as they lack adaptations to survive cold winters, such as the capacity to hibernate. However, the lower diversity of Vespertilionidae in the Neotropics is better explained by competition with a diverse pre-existing community of bats than by niche conservatism.

  18. Investigating the context-dependency of plant-soil-AMF-microbe interactions along a pollution gradient

    Science.gov (United States)

    Glassman, S. I.; Casper, B. B.

    2010-12-01

    Background/Question/Methods Investigating how arbuscular mycorrhizal fungi (AMF)-plant interactions vary with edaphic conditions provides an opportunity to test the context-dependency of interspecific interactions, which is currently recognized as a major avenue of future research. We study plant-mycorrhiza symbiotic relationships along a gradient of heavy metal contamination at a recently revegetated “Superfund” site on Blue Mountain, in Palmerton, Pennsylvania. We investigated the interactions involving the native mycorrhizal fungi, non-mycorrhizal soil microbes, soil, and two plant species (a C3 and C4 grass) along the contamination gradient. The native C3 study species Deschampsia flexuosa, is dominant along the gradient and established naturally; the C4 Sorghastrum nutans, is native to Pennsylvania but not to the site and was introduced during restoration. Because C4 grasses are obligate mycotrophs, we expected S. nutans to have a different effect on and response to the soil symbiont community than the C3 grass. We carried out a full factorial greenhouse experiment using field-collected seeds of D. flexuosa and S. nutans, soil, AMF spores, and non-mycorrhizal microbes from both high and low contaminated ends of the gradient. After 11 weeks of growth in the greenhouses, we harvested above and belowground plant biomass, and quantified AMF root colonization and AMF sporulation. Results/Conclusions Our results indicate that context-dependent function is an important factor driving specific ecological interactions between plants and soil microbes. We found that soil origin significantly affected plant growth. Plants from both species grew much larger in soil from low contaminated (LC) origin than high contaminated (HC) origin. Furthermore, we found that the efficacy of AMF in promoting plant growth depended on AMF origin. Specifically, AMF from LC improved growth of D. flexuosa best in either soil background and improved survivorship of S. nutans in HC soil

  19. Probiotic Diversity Enhances Rhizosphere Microbiome Function and Plant Disease Suppression

    OpenAIRE

    Hu, Jie; Wei, Zhong; Friman, Ville Petri; Gu, Shao-Hua; Wang, Xiao-Fang; Eisenhauer, Nico; Yang, Tian-jie; Ma, Jing; Shen, Qi-Rong; Xu, Yang-chun; Jousset, Alexandre

    2016-01-01

    Bacterial communities associated with plant roots play an important role in the suppression of soil-borne pathogens, and multispecies probiotic consortia may enhance disease suppression efficacy. Here we introduced defined Pseudomonas species consortia into naturally complex microbial communities and measured the importance of Pseudomonas community diversity for their survival and the suppression of the bacterial plant pathogen Ralstonia solanacearum in the tomato rhizosphere microbiome. The ...

  20. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotide...... angiosperms. This analysis has enabled cell wall diversity to be placed in a phylogenetic context, and, when integrated with transcriptomic and genomic analysis has contributed to our understanding of important aspects of plant evolution....

  1. Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon

    Science.gov (United States)

    McCoy-Sulentic, Miles; Kolb, Thomas; Merritt, David; Palmquist, Emily C.; Ralston, Barbara E.; Sarr, Daniel; Shafroth, Patrick B.

    2017-01-01

    Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over hydrologic zones and gradients in years 2013 and 2014 in the riparian plant community along the Colorado River in the Grand Canyon. Vegetation cover was lowest in the frequently inundated active channel zone, indicating constraints on plant establishment and production by flood disturbance and anaerobic stress. Changes in trait values over hydrologic zones and inundation gradients indicate that frequently inundated plots exhibit a community-level ruderal strategy with adaptation to submergence (high SLA and low SSG, height, seed mass, C4 relative cover), whereas less frequently inundated plots exhibit adaptation to drought and infrequent flood disturbance (low SLA and high SSG, height, seed mass, C4 relative cover). Variation in traits not associated with inundation suggests niche differentiation and multiple modes of community assembly. The results enhance understanding of future responses of riparian communities of the Grand Canyon to anticipated drying and changes in hydrologic regime.

  2. Plant diversity moderates drought stress in grasslands: Implications from a large real-world study on (13)C natural abundances.

    Science.gov (United States)

    Klaus, Valentin H; Hölzel, Norbert; Prati, Daniel; Schmitt, Barbara; Schöning, Ingo; Schrumpf, Marion; Solly, Emily F; Hänsel, Falk; Fischer, Markus; Kleinebecker, Till

    2016-10-01

    Land-use change and intensification play a key role in the current biodiversity crisis. The resulting species loss can have severe effects on ecosystem functions and services, thereby increasing ecosystem vulnerability to climate change. We explored whether land-use intensification (i.e. fertilization intensity), plant diversity and other potentially confounding environmental factors may be significantly related to water use (i.e. drought stress) of grassland plants. Drought stress was assessed using δ(13)C abundances in aboveground plant biomass of 150 grassland plots across a gradient of land-use intensity. Under water shortage, plants are forced to increasingly take up the heavier (13)C due to closing stomata leading to an enrichment of (13)C in biomass. Plants were sampled at the community level and for single species, which belong to three different functional groups (one grass, one herb, two legumes). Results show that plant diversity was significantly related to the δ(13)C signal in community, grass and legume biomass indicating that drought stress was lower under higher diversity, although this relation was not significant for the herb species under study. Fertilization, in turn, mostly increased drought stress as indicated by more positive δ(13)C values. This effect was mostly indirect by decreasing plant diversity. In line with these results, we found similar patterns in the δ(13)C signal of the organic matter in the topsoil, indicating a long history of these processes. Our study provided strong indication for a positive biodiversity-ecosystem functioning relationship with reduced drought stress at higher plant diversity. However, it also underlined a negative reinforcing situation: as land-use intensification decreases plant diversity in grasslands, this might subsequently increases drought sensitivity. Vice-versa, enhancing plant diversity in species-poor agricultural grasslands may moderate negative effects of future climate change.

  3. Plant Sterol Diversity in Pollen from Angiosperms.

    Science.gov (United States)

    Villette, Claire; Berna, Anne; Compagnon, Vincent; Schaller, Hubert

    2015-08-01

    Here we have examined the composition of free sterols and steryl esters of pollen from selected angiosperm species, as a first step towards a comprehensive analysis of sterol biogenesis in the male gametophyte. We detected four major sterol structural groups: cycloartenol derivatives bearing a 9β,19-cyclopropyl group, sterols with a double bond at C-7(8), sterols with a double bond at C-5(6), and stanols. All these groups were unequally distributed among species. However, the distribution of sterols as free sterols or as steryl esters in pollen grains indicated that free sterols were mostly Δ(5)-sterols and that steryl esters were predominantly 9β,19-cyclopropyl sterols. In order to link the sterol composition of a pollen grain at anthesis with the requirement for membrane lipid constituents of the pollen tube, we germinated pollen grains from Nicotiana tabacum, a model plant in reproductive biology. In the presence of radiolabelled mevalonic acid and in a time course series of measurements, we showed that cycloeucalenol was identified as the major neosynthesized sterol. Furthermore, the inhibition of cycloeucalenol neosynthesis by squalestatin was in full agreement with a de novo biogenesis and an apparent truncated pathway in the pollen tube.

  4. Diversity and distribution of medicinal plants in North Sinai, Egypt

    African Journals Online (AJOL)

    Administrator

    2008-07-22

    Jul 22, 2008 ... Key words: Conservation, diversity, habitats, human impacts, medicinal plants, vegetation. INTRODUCTION ... of which 279 were recorded in the Mediterranean coastal ... graphic location (latitude and longitude), and altitude were recorded ... were selected in inland district, the transition zone between the.

  5. Plant evolution: pulses of extinction and speciation in gymnosperm diversity.

    Science.gov (United States)

    Davis, Charles C; Schaefer, Hanno

    2011-12-20

    Living gymnosperms represent the survivors of ancient seed plant lineages whose fossil record reaches back 270 million years. Two recent studies find that recent pulses of extinction and speciation have shaped today's gymnosperm diversity, contradicting the widespread assumption that gymnosperms have remained largely unchanged for tens of millions of years.

  6. Species richness and diversity in different functional groups across environmental stress gradients : a model for marine rocky shores

    NARCIS (Netherlands)

    Scrosati, Ricardo A.; van Genne, Barbara; Heaven, Christine S.; Watt, Cortney A.

    2011-01-01

    We present a model predicting how the species richness and diversity within benthic functional groups should vary across the full environmental stress gradient across which a regional biota from marine rocky shores can occur. Built upon previous models, our model makes predictions for sessile specie

  7. Elevational gradients in phylogenetic structure of ant communities reveal the interplay of biotic and abiotic constraints on diversity

    DEFF Research Database (Denmark)

    Machac, Antonin; Janda, Milan; Dunn, Robert R.

    2011-01-01

    A central focus of ecology and biogeography is to determine the factors that govern spatial variation in biodiversity. Here, we examined patterns of ant diversity along climatic gradients in three temperate montane systems: Great Smoky Mountains National Park (USA), Chiricahua Mountains (USA), an...

  8. 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.

  9. Archaeal community diversity and abundance changes along a natural salinity gradient in estuarine sediments.

    Science.gov (United States)

    Webster, Gordon; O'Sullivan, Louise A; Meng, Yiyu; Williams, Angharad S; Sass, Andrea M; Watkins, Andrew J; Parkes, R John; Weightman, Andrew J

    2015-02-01

    Archaea are widespread in marine sediments, but their occurrence and relationship with natural salinity gradients in estuarine sediments is not well understood. This study investigated the abundance and diversity of Archaea in sediments at three sites [Brightlingsea (BR), Alresford (AR) and Hythe (HY)] along the Colne Estuary, using quantitative real-time PCR (qPCR) of 16S rRNA genes, DNA hybridization, Archaea 16S rRNA and mcrA gene phylogenetic analyses. Total archaeal 16S rRNA abundance in sediments were higher in the low-salinity brackish sediments from HY (2-8 × 10(7) 16S rRNA gene copies cm(-3)) than the high-salinity marine sites from BR and AR (2 × 10(4)-2 × 10(7) and 4 × 10(6)-2 × 10(7) 16S rRNA gene copies cm(-3), respectively), although as a proportion of the total prokaryotes Archaea were higher at BR than at AR or HY. Phylogenetic analysis showed that members of the 'Bathyarchaeota' (MCG), Thaumarchaeota and methanogenic Euryarchaeota were the dominant groups of Archaea. The composition of Thaumarchaeota varied with salinity, as only 'marine' group I.1a was present in marine sediments (BR). Methanogen 16S rRNA genes from low-salinity sediments at HY were dominated by acetotrophic Methanosaeta and putatively hydrogentrophic Methanomicrobiales, whereas the marine site (BR) was dominated by mcrA genes belonging to methylotrophic Methanococcoides, versatile Methanosarcina and methanotrophic ANME-2a. Overall, the results indicate that salinity and associated factors play a role in controlling diversity and distribution of Archaea in estuarine sediments.

  10. Fungal assemblages associated with roots of halophytic and non-halophytic plant species vary differentially along a salinity gradient.

    Science.gov (United States)

    Maciá-Vicente, Jose G; Ferraro, Valeria; Burruano, Santella; Lopez-Llorca, Luis V

    2012-10-01

    Structure of fungal communities is known to be influenced by host plants and environmental conditions. However, in most cases, the dynamics of these variation patterns are poorly understood. In this work, we compared richness, diversity, and composition between assemblages of endophytic and rhizospheric fungi associated to roots of two plants with different lifestyles: the halophyte Inula crithmoides and the non-halophyte I. viscosa (syn. Dittrichia viscosa L.), along a spatially short salinity gradient. Roots and rhizospheric soil from these plants were collected at three points between a salt marsh and a sand dune, and fungi were isolated and characterized by ITS rDNA sequencing. Isolates were classified in a total of 90 operational taxonomic units (OTUs), belonging to 17 fungal orders within Ascomycota and Basidiomycota. Species composition of endophytic and soil communities significantly differed across samples. Endophyte communities of I. crithmoides and I. viscosa were only similar in the intermediate zone between the salt marsh and the dune, and while the latter displayed a single, generalist association of endophytes, I. crithmoides harbored different assemblages along the gradient, adapted to the specific soil conditions. In the lower salt marsh, root assemblages were strongly dominated by a single dark septate sterile fungus, also prevalent in other neighboring salt marshes. Interestingly, although its occurrence was positively correlated to soil salinity, in vitro assays revealed a strong inhibition of its growth by salts. Our results suggest that host lifestyle and soil characteristics have a strong effect on endophytic fungi and that environmental stress may entail tight plant-fungus relationships for adaptation to unfavorable conditions.

  11. Plant invasion and speciation along elevational gradients on the oceanic island La Palma, Canary Islands

    DEFF Research Database (Denmark)

    Steinbauer, Manuel; Irl, Severin David Howard; González-Mancebo, Juana Maria

    2016-01-01

    and anthropogenic filters, thus controlling the dispersal and establishment of species. Here, we investigate speciation and invasion processes along elevational gradients. Methods: We assess the vascular plant species richness as well as the number and percentage of endemic species and non-native species......Background: Ecosystems that provide environmental opportunities but are poor in species and functional richness generally support speciation as well as invasion processes. These processes are expected not to be equally effective along elevational gradients due to specific ecological, spatial......-Madeira endemics did not show a relationship with elevation. Non-native species richness (indicating invasion) peaked at 500 m elevation and showed a consistent decline until about 1200 m elevation. Above that limit no non-native species were present in the studied elevational gradients. Conclusion: Ecological...

  12. Species composition, diversity and stratification in subtropical evergreen broadleaf forests along a latitudinal thermal gradient in the Ryukyu Archipelago, Japan

    Directory of Open Access Journals (Sweden)

    S.M. Feroz

    2015-07-01

    Full Text Available A well-developed evergreen broadleaf forest exists in the northern part of Okinawa and in the central part of the Ishigaki Islands in the Ryukyu Archipelago, Japan. All woody plants were identified to species level and their heights and diameters were measured in a 750m2 plot in Okinawa and a 400m2 plot in the Ishigaki Islands. Species overlap, dominance, diversity, multi-strata structure, and spatial distribution were calculated. The floristic composition in Okinawa was found to be different from that in Ishigaki. The species overlap between strata was higher in Okinawa than in Ishigaki. Species diversity and evenness tended to increase from the top down in Okinawa and the reverse in Ishigaki. Mean tree weight of each stratum decreased and tree density increased from top down in both forests. This trend resembled the mean weight–density trajectory of self-thinning plant populations. The degree of stand stratification, species richness and species diversity for trees with DBH ⩾4.5  cm increased along the latitudinal thermal gradient in the Ryukyu Archipelago. Thus, trees in the lower strata of Okinawa and upper strata of Ishigaki are important for sustainable maintenance of higher woody species diversity in the Ryukyu Archipelago.

  13. Diversity of Aphanizomenon flos-aquae (cyanobacterium) populations along a Baltic Sea salinity gradient.

    Science.gov (United States)

    Laamanen, Maria J; Forsström, Laura; Sivonen, Kaarina

    2002-11-01

    Colony-forming cyanobacteria of the genus Aphanizomenon form massive blooms in the brackish water of the Baltic Sea during the warmest summer months. There have been recent suggestions claiming that the Baltic Sea Aphanizomenon species may be different from Aphanizomenon flos-aquae found in lakes. In this study, we examined variability in the morphology and 16S-23S rRNA internal transcribed spacer (ITS) sequences of A. flos-aquae populations along a salinity gradient from a string of lakes to a fjord-like extension of the Baltic Sea to the open Baltic Sea. Morphological differences among the populations were negligible. We found that the Baltic Sea was dominated (25 out of 27 sequences) by one ITS1-S (shorter band of ITS 1 [ITS1]) genotype, which also was found in the lakes. The lake populations of A. flos-aquae tended to be genetically more diverse than the Baltic Sea populations. Since the lake ITS1-S genotypes of A. flos-aquae are continuously introduced to the Baltic Sea via inflowing waters, it seems that only one ITS1 genotype is able to persist in the Baltic Sea populations. The results suggest that one of the ITS1-S genotypes found in the lakes is better adapted to the conditions of the Baltic Sea and that natural selection removes most of the lake genotypes from the Baltic Sea A. flos-aquae populations.

  14. Monitoring the lactic acid bacterial diversity during shochu fermentation by PCR-denaturing gradient gel electrophoresis.

    Science.gov (United States)

    Endo, Akihito; Okada, Sanae

    2005-03-01

    The presence of lactic acid bacteria (LAB) during shochu fermentation was monitored by PCR-denaturing gradient gel electrophoresis (DGGE) and by bacteriological culturing. No LAB were detected from fermented mashes by PCR-DGGE using a universal bacterial PCR primer set. However, PCR-DGGE using a new primer specific for the 16S rDNA of Lactococcus, Streptococcus, Tetragenococcus, Enterococcus, and Vagococcus and two primers specific for the 16S rDNA of Lactobacillus, Pediococcus, Leuconostoc, and Weissella revealed that Enterococcus faecium, Lactobacillus casei, Lactobacillus fermentum, Lactobacillus nagelii, Lactobacillus plantarum, Lactococcus lactis, Leuconostoc citreum, Leuconostoc mesenteroides, and Weissella cibaria inhabited in shochu mashes. It was also found that the LAB community composition during shochu fermentation changed after the main ingredient and water were added during the fermentation process. Therefore, we confirmed that PCR-DGGE using all three primers specific for groups of LAB together was well suited to the study of the LAB diversity in shochu mashes. The results of DGGE profiles were similar to the results of bacteriological culturing. In conclusion, LAB are present during shochu fermentation but not dominant.

  15. Assessing the diversity of bacterial communities associated with plants

    Science.gov (United States)

    Andreote, Fernando Dini; Azevedo, João Lúcio; Araújo, Welington Luiz

    2009-01-01

    Plant–bacteria interactions result from reciprocal recognition between both species. These interactions are responsible for essential biological processes in plant development and health status. Here, we present a review of the methodologies applied to investigate shifts in bacterial communities associated with plants. A description of techniques is made from initial isolations to culture-independent approaches focusing on quantitative Polymerase Chain Reaction in real time (qPCR), Denaturing Gradient Gel Electrophoresis (DGGE), clone library construction and analysis, the application of multivariate analyses to microbial ecology data and the upcoming high throughput methodologies such as microarrays and pyrosequencing. This review supplies information about the development of traditional methods and a general overview about the new insights into bacterial communities associated with plants. PMID:24031382

  16. Biogeographical Interpretation of Elevational Patterns of Genus Diversity of Seed Plants in Nepal

    Science.gov (United States)

    Li, Miao; Feng, Jianmeng

    2015-01-01

    This study tests if the biogeographical affinities of genera are relevant for explaining elevational plant diversity patterns in Nepal. We used simultaneous autoregressive (SAR) models to investigate the explanatory power of several predictors in explaining the diversity-elevation relationships shown in genera with different biogeographical affinities. Delta akaike information criterion (ΔAIC) was used for multi-model inferences and selections. Our results showed that both the total and tropical genus diversity peaked below the mid-point of the elevational gradient, whereas that of temperate genera had a nearly symmetrical, unimodal relationship with elevation. The proportion of temperate genera increased markedly with elevation, while that of tropical genera declined. Compared to tropical genera, temperate genera had wider elevational ranges and were observed at higher elevations. Water-related variables, rather than mid-domain effects (MDE), were the most significant predictors of elevational patterns of tropical genus diversity. The temperate genus diversity was influenced by energy availability, but only in quadratic terms of the models. Though climatic factors and mid-domain effects jointly explained most of the variation in the diversity of temperate genera with elevation, the former played stronger roles. Total genus diversity was most strongly influenced by climate and the floristic overlap of tropical and temperate floras, while the influences of mid-domain effects were relatively weak. The influences of water-related and energy-related variables may vary with biogeographical affinities. The elevational patterns may be most closely related to climatic factors, while MDE may somewhat modify the patterns. Caution is needed when investigating the causal factors underlying diversity patterns for large taxonomic groups composed of taxa of different biogeographical affinities. Right-skewed diversity-elevation patterns may be produced by the differential

  17. Biogeographical Interpretation of Elevational Patterns of Genus Diversity of Seed Plants in Nepal.

    Science.gov (United States)

    Li, Miao; Feng, Jianmeng

    2015-01-01

    This study tests if the biogeographical affinities of genera are relevant for explaining elevational plant diversity patterns in Nepal. We used simultaneous autoregressive (SAR) models to investigate the explanatory power of several predictors in explaining the diversity-elevation relationships shown in genera with different biogeographical affinities. Delta akaike information criterion (ΔAIC) was used for multi-model inferences and selections. Our results showed that both the total and tropical genus diversity peaked below the mid-point of the elevational gradient, whereas that of temperate genera had a nearly symmetrical, unimodal relationship with elevation. The proportion of temperate genera increased markedly with elevation, while that of tropical genera declined. Compared to tropical genera, temperate genera had wider elevational ranges and were observed at higher elevations. Water-related variables, rather than mid-domain effects (MDE), were the most significant predictors of elevational patterns of tropical genus diversity. The temperate genus diversity was influenced by energy availability, but only in quadratic terms of the models. Though climatic factors and mid-domain effects jointly explained most of the variation in the diversity of temperate genera with elevation, the former played stronger roles. Total genus diversity was most strongly influenced by climate and the floristic overlap of tropical and temperate floras, while the influences of mid-domain effects were relatively weak. The influences of water-related and energy-related variables may vary with biogeographical affinities. The elevational patterns may be most closely related to climatic factors, while MDE may somewhat modify the patterns. Caution is needed when investigating the causal factors underlying diversity patterns for large taxonomic groups composed of taxa of different biogeographical affinities. Right-skewed diversity-elevation patterns may be produced by the differential

  18. Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China.

    Science.gov (United States)

    Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y Jun

    2016-01-01

    Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region.

  19. Plant diversity in the homegardens of Karwar, Karnataka, India

    Directory of Open Access Journals (Sweden)

    SHIVANAND BHAT

    2014-10-01

    Full Text Available Bhat S, Bhandary MJ, Rajanna L. 2014. Plant diversity in the homegardens of Karwar, Karnataka, India. Biodiversitas 15: 229-235. A study was conducted in 50 selected home gardens of Karwar, Karnataka, India to document their floristic diversity and composition with regard to life forms and uses. As many as 210 species of flowering plants belonging to 69 families were recorded. Euphorbiaceae (13species, Apocynaceae (11spp., Cucurbitaceae (10 spp. and Fabaceae (10 spp. are the predominant families. Shrubs are the dominant life forms (73 spp. followed by trees (61 spp., herbs (42 spp. and climbers (24 spp.. Areca palm (Areca catechu, coconut palm (Cocos nucifera, mango tree (Mangifera indica, banana (Musa paradisiaca, shoe flower (Hibiscus rosa-sinensis and holy basil (Ocimum tenuiflorum are the most common plants occurring in all of the 50 studied gardens. 38% of the plant species are grown mainly for ornamental and aesthetic purposes while 33% of the species are used for obtaining food products like fruits and vegetables and 22% of the plants are mainly used for medicinal purposes. The predominance of ornamental species makes the home gardens of Karwar different from those occurring in other regions in which mostly food plants form the major component.

  20. The microbiome of medicinal plants: diversity and importance for plant growth, quality and health

    Directory of Open Access Journals (Sweden)

    Martina eKöberl

    2013-12-01

    Full Text Available Past medicinal plant research primarily focused on bioactive phytochemicals, however the focus is currently shifting due to the recognition that a significant number of phytotherapeutic compounds are actually produced by associated microbes or through interaction with their host. Medicinal plants provide an enormous bioresource of potential use in modern medicine and agriculture, yet their microbiome is largely unknown. The objective of this review is i to introduce novel insights into the plant microbiome with a focus on medicinal plants, ii to provide details about plant- and microbe-derived ingredients of medicinal plants, and iii to discuss possibilities for plant growth promotion and plant protection for commercial cultivation of medicinal plants. In addition, we also present a case study performed both to analyse the microbiome of three medicinal plants (Matricaria chamomilla L., Calendula officinalis L. and Solanum distichum Schumach. and Thonn. cultivated on organically managed Egyptian desert farm and to develop biological control strategies. The soil microbiome of the desert ecosystem was comprised of a high abundance of Gram-positive bacteria of prime importance for pathogen suppression under arid soil conditions. For all three plants, we observed a clearly plant-specific selection of the microbes as well as highly specific diazotrophic communities that overall identify plant species as important drivers in structural and functional diversity. Lastly, native Bacillus spec. div. strains were able to promote plant growth and elevate the plants’ flavonoid production. These results underline the numerous links between the plant-associated microbiome and the plant metabolome.

  1. Uncovering unseen fungal diversity from plant DNA banks

    Directory of Open Access Journals (Sweden)

    Erin M. Datlof

    2017-08-01

    Full Text Available Throughout the world DNA banks are used as storage repositories for genetic diversity of organisms ranging from plants to insects to mammals. Designed to preserve the genetic information for organisms of interest, these banks also indirectly preserve organisms’ associated microbiomes, including fungi associated with plant tissues. Studies of fungal biodiversity lag far behind those of macroorganisms, such as plants, and estimates of global fungal richness are still widely debated. Utilizing previously collected specimens to study patterns of fungal diversity could significantly increase our understanding of overall patterns of biodiversity from snapshots in time. Here, we investigated the fungi inhabiting the phylloplane among species of the endemic Hawaiian plant genus, Clermontia (Campanulaceae. Utilizing next generation DNA amplicon sequencing, we uncovered approximately 1,780 fungal operational taxonomic units from just 20 DNA bank samples collected throughout the main Hawaiian Islands. Using these historical samples, we tested the macroecological pattern of decreasing community similarity with decreasing geographic proximity. We found a significant distance decay pattern among Clermontia associated fungal communities. This study provides the first insights into elucidating patterns of microbial diversity through the use of DNA bank repository samples.

  2. Plant-herbivore interactions along elevational gradient: Comparison of field and common garden data

    Science.gov (United States)

    Rokaya, Maan Bahadur; Dostálek, Tomáš; Münzbergová, Zuzana

    2016-11-01

    In response to climate change, various organisms tend to migrate to higher elevations and latitudes. Unequal migration rates of plants and animals are expected to result in changes in the type and intensity of their interactions such as plant-herbivore interactions. In the present study, we studied the extent of herbivore damage in Salvia nubicola along an elevational gradient in Manang, central Nepal. A common garden experiment was also carried out by sowing seeds collected from different populations along the elevational gradient. As expected, the extent of herbivore damage in the field was significantly lower at higher elevations, and it increased with the population size and at sites without shrubs. In the common garden experiment, herbivore damage was higher in plants originating from lower elevations and from more open habitats. While higher herbivore pressure in the field at lower elevations may suggest that plants will be better protected against herbivores at lower elevations, the common garden study demonstrated the opposite. A possible explanation could be that plants from higher elevations have to adapt to extreme conditions, and lower palatability is a side effect of these adaptations. Thus, S. nubicola in the Himalayan region is likely to survive the expected higher herbivore pressure caused by an upward shift of herbivores under future climate change. Future studies should attempt to elucidate generality of such a conclusion by studying multiple species along similar gradients. Our results from comparison of the field and common garden study suggest that future experiments need to include comparisons in common environments to understand the expected response of plants to changes in herbivore pressure.

  3. Integrating the effects of latitude and altitude on the spatial differentiation of plant community diversity in a mountainous ecosystem in China

    Science.gov (United States)

    Xu, Manhou; Ma, Li; Jia, Yanyan; Liu, Min

    2017-01-01

    Varying patterns of plant community diversity along geographical gradients are a significant topic in biodiversity research. Here, to explore the integrated effects of latitude and altitude on the plant community diversity in a mountainous ecosystem, we set Guancen Mountain in the northern section, Guandi Mountain in the middle section, and Wulu Mountain in the southern section of the Lvliang Mountains as study areas, and the plant community diversity (basal diameter and height of tree and species diversity indices of shrub and herb) was measured horizontally at different latitude gradients and vertically at different altitude gradients in late July 2015. The results showed that (1) the trees were taller and wider at the middle latitude and higher altitude with a stronger spatial heterogeneity in the structures along the latitudinal and altitudinal gradients. The evergreen tree growth preceded that of the deciduous trees in the higher latitude and lower altitude regions, whereas the deciduous tree growth preceded that of the evergreen trees in the middle latitude and higher altitude regions. (2) Shrubs and herbs tended to grow well in the lower latitude and middle-lower altitude regions. The shrubs had a larger species diversity at lower latitude and lower altitude, but the species diversity of the herbs was not sensitive to the influences of the latitudinal and altitudinal gradients. With the latitude and altitude increasing, perennial herbs tended to grow well at higher latitude and higher altitude, while annual herbs tended to thrive at the middle latitude and lower altitude. In conclusion, environmental deviations caused by latitudinal and altitudinal gradients had great influences on the spatial distributions of the plant community diversity in the Lvliang Mountains. PMID:28323909

  4. What can multiple phylogenies say about the latitudinal diversity gradient? A new look at the tropical conservatism, out of the tropics, and diversification rate hypotheses.

    Science.gov (United States)

    Jansson, Roland; Rodríguez-Castañeda, Genoveva; Harding, Larisa E

    2013-06-01

    We reviewed published phylogenies and selected 111 phylogenetic studies representing mammals, birds, insects, and flowering plants. We then mapped the latitudinal range of all taxa to test the relative importance of the tropical conservatism, out of the tropics, and diversification rate hypotheses in generating latitudinal diversity gradients. Most clades originated in the tropics, with diversity peaking in the zone of origin. Transitions of lineages between latitudinal zones occurred at 16-22% of the tree nodes. The most common type of transition was range expansions of tropical lineages to encompass also temperate latitudes. Thus, adaptation to new climatic conditions may not represent a major obstacle for many clades. These results contradict predictions of the tropical conservatism hypothesis (i.e., few clades colonizing extratropical latitudes), but support the out-of-the-tropics model (i.e., tropical originations and subsequent latitudinal range expansions). Our results suggest no difference in diversification between tropical and temperate sister lineages; thus, diversity of tropical clades was not explained by higher diversification rates in this zone. Moreover, lineages with latitudinal stasis diversified more compared to sister lineages entering a new latitudinal zone. This preserved preexisting diversity differences between latitudinal zones and can be considered a new mechanism for why diversity tends to peak in the zone of origin.

  5. Plant diversity in different bioclimatic zones in Tunisia

    Directory of Open Access Journals (Sweden)

    Hana You

    2016-03-01

    Full Text Available The Republic of Tunisia, located in northern Africa, faces various environmental challenges caused by anthropogenic practices such as overgrazing, deforestation, and desertification. The conversion of natural ecosystems is the major cause of plant biodiversity loss. Tunisia can be divided into three main climatic zones as follows: a northern Mediterranean climate zone, a central steppe climate zone, and a southern desert climate zone. Because of this great environmental diversity, there are distinctive vegetation and various genetic resources in Tunisia. This research was conducted to investigate plant biodiversity within the various bioclimatic zones and to characterize useful plant resources in Tunisia. We investigated native, medicinal and aromatic, desert, and soil erosion control plant species.

  6. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient.

    Science.gov (United States)

    Wilson, Hannah; Johnson, Bart R; Bohannan, Brendan; Pfeifer-Meister, Laurel; Mueller, Rebecca; Bridgham, Scott D

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM) was used to determine the direct and indirect effects of experimental warming on AMF colonization. Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization.

  7. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient

    Science.gov (United States)

    Johnson, Bart R.; Bohannan, Brendan; Pfeifer-Meister, Laurel; Mueller, Rebecca; Bridgham, Scott D.

    2016-01-01

    Background: Arbuscular mycorrhizal fungi (AMF) provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. Methods: We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM) was used to determine the direct and indirect effects of experimental warming on AMF colonization. Results: Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. Discussion: A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization. PMID:27280074

  8. Experimental warming decreases arbuscular mycorrhizal fungal colonization in prairie plants along a Mediterranean climate gradient

    Directory of Open Access Journals (Sweden)

    Hannah Wilson

    2016-06-01

    Full Text Available Background: Arbuscular mycorrhizal fungi (AMF provide numerous services to their plant symbionts. Understanding climate change effects on AMF, and the resulting plant responses, is crucial for predicting ecosystem responses at regional and global scales. We investigated how the effects of climate change on AMF-plant symbioses are mediated by soil water availability, soil nutrient availability, and vegetation dynamics. Methods: We used a combination of a greenhouse experiment and a manipulative climate change experiment embedded within a Mediterranean climate gradient in the Pacific Northwest, USA to examine this question. Structural equation modeling (SEM was used to determine the direct and indirect effects of experimental warming on AMF colonization. Results: Warming directly decreased AMF colonization across plant species and across the climate gradient of the study region. Other positive and negative indirect effects of warming, mediated by soil water availability, soil nutrient availability, and vegetation dynamics, canceled each other out. Discussion: A warming-induced decrease in AMF colonization would likely have substantial consequences for plant communities and ecosystem function. Moreover, predicted increases in more intense droughts and heavier rains for this region could shift the balance among indirect causal pathways, and either exacerbate or mitigate the negative, direct effect of increased temperature on AMF colonization.

  9. Intraspecific chemical diversity among neighbouring plants correlates positively with plant size and herbivore load but negatively with herbivore damage

    NARCIS (Netherlands)

    Bustos-segura, Carlos; Poelman, Erik H.; Reichelt, Michael; Gershenzon, Jonathan; Gols, Rieta; Scherber, Christoph

    2017-01-01

    Intraspecific plant diversity can modify the properties of associated arthropod communities and plant fitness. However, it is not well understood which plant traits determine these ecological effects. We explored the effect of intraspecific chemical diversity among neighbouring plants on the associa

  10. Fungal diversity associated with Hawaiian Drosophila host plants.

    Directory of Open Access Journals (Sweden)

    Brian S Ort

    Full Text Available Hawaiian Drosophila depend primarily, sometimes exclusively, on specific host plants for oviposition and larval development, and most specialize further on a particular decomposing part of that plant. Differences in fungal community between host plants and substrate types may establish the basis for host specificity in Hawaiian Drosophila. Fungi mediate decomposition, releasing plant micronutrients and volatiles that can indicate high quality substrates and serve as cues to stimulate oviposition. This study addresses major gaps in our knowledge by providing the first culture-free, DNA-based survey of fungal diversity associated with four ecologically important tree genera in the Hawaiian Islands. Three genera, Cheirodendron, Clermontia, and Pisonia, are important host plants for Drosophila. The fourth, Acacia, is not an important drosophilid host but is a dominant forest tree. We sampled fresh and rotting leaves from all four taxa, plus rotting stems from Clermontia and Pisonia. Based on sequences from the D1/D2 domain of the 26S rDNA gene, we identified by BLAST search representatives from 113 genera in 13 fungal classes. A total of 160 operational taxonomic units, defined on the basis of ≥97% genetic similarity, were identified in these samples, but sampling curves show this is an underestimate of the total fungal diversity present on these substrates. Shannon diversity indices ranged from 2.0 to 3.5 among the Hawaiian samples, a slight reduction compared to continental surveys. We detected very little sharing of fungal taxa among the substrates, and tests of community composition confirmed that the structure of the fungal community differed significantly among the substrates and host plants. Based on these results, we hypothesize that fungal community structure plays a central role in the establishment of host preference in the Hawaiian Drosophila radiation.

  11. FISH DIVERSITY ALONG THE LONGITUDINAL GRADIENT IN A MAN–MADE LAKE OF WEST AFRICA, TAABO HYDROELECTRIC RESERVOIR, IVORY COAST

    Directory of Open Access Journals (Sweden)

    N. G. Aliko

    2010-04-01

    Full Text Available Fish assemblage patterns in Taabo Reservoir, a hydroelectric lake of Ivory Coast, were studied and related to the longitudinal gradient (river–dam gradient composed of riverine, transitional, and lacustrine zones. Data were collected at 5 stations and each one was sampled during 5 surveys. Fish community structure was analysed using alpha and beta diversity indices. In total, 53 fish species were obtained in the whole ecosystem. Total species richness recorded at each ecological zone was 42, 43 and 45 species respectively in the riverine, transitional and lacustrine zones. Alpha diversity did not differed significantly along the longitudinal gradient but reached the highest value (33 species in the transitional zone and the lowest (18 species occurred in both the riverine and lacustrine zones. Temporal variability of Alpha diversity according to the hydrological regime of the lake differed with the zone. Beta diversity showed that fish assemblages similarity was higher between the transitional and the riverine zones (βw = 0.43 and lower between the riverine and the lacustrine zones (βw = 0.79.

  12. Conserved Gene Expression Programs in Developing Roots from Diverse Plants.

    Science.gov (United States)

    Huang, Ling; Schiefelbein, John

    2015-08-01

    The molecular basis for the origin and diversification of morphological adaptations is a central issue in evolutionary developmental biology. Here, we defined temporal transcript accumulation in developing roots from seven vascular plants, permitting a genome-wide comparative analysis of the molecular programs used by a single organ across diverse species. The resulting gene expression maps uncover significant similarity in the genes employed in roots and their developmental expression profiles. The detailed analysis of a subset of 133 genes known to be associated with root development in Arabidopsis thaliana indicates that most of these are used in all plant species. Strikingly, this was also true for root development in a lycophyte (Selaginella moellendorffii), which forms morphologically different roots and is thought to have evolved roots independently. Thus, despite vast differences in size and anatomy of roots from diverse plants, the basic molecular mechanisms employed during root formation appear to be conserved. This suggests that roots evolved in the two major vascular plant lineages either by parallel recruitment of largely the same developmental program or by elaboration of an existing root program in the common ancestor of vascular plants.

  13. Acidification of sandy grasslands - consequences for plant diversity

    DEFF Research Database (Denmark)

    Olsson, Pål Axel; Mårtensson, Linda-Maria; Bruun, Hans Henrik

    2009-01-01

    Questions: (1) Does soil acidification in calcareous sandy grasslands lead to loss of plant diversity? (2) What is the relationship between the soil content of lime and the plant availability of mineral nitrogen (N) and phosphorus (P) in sandy grasslands? Location: Sandy glaciofluvial deposits...... in south-eastern Sweden covered by xeric sand calcareous grasslands (EU habitat directive 6120). Methods: Soil and vegetation were investigated in most of the xeric sand calcareous grasslands in the Scania region (136 sample plots distributed over four or five major areas and about 25 different sites...

  14. Decoupling of nutrient element cycles in soil and plants across an altitude gradient

    Science.gov (United States)

    Tan, Qiqi; Wang, Guoan

    2016-10-01

    Previous studies have examined the decoupling of C, N, and P under rapid changes in climate. While this may occur in different environment types, such climactic changes have been reported over short distances in mountainous terrain. We hypothesized that the decoupling of C, N, and P could also occur in response to increases in altitude. We sampled soil and plants from Mount Gongga, Sichuan Province, China. Soil C and N were not related to altitude, whereas soil P increased with altitude. Soil N did not change with mean annual temperature (MAT), mean annual precipitation (MAP), vegetation and soil types, whereas soil P varied with MAT and vegetation type. Plant C remained constant with increasing altitude; plant N exhibited a quadratic change trend along the altitude gradient, with a turning point at 2350 m above average sea level; and plant P decreased with altitude. MAP mostly accounted for the variation in plant P. MAT was responsible for the variation of plant N at elevations below 2350 m, whereas MAT and vegetation type were the dominant influential factors of plants growing above 2350 m. Thus, the decoupling of C, N, and P in both soil and plants was significantly affected by altitude.

  15. Review: Mycoendophytes in medicinal plants: Diversity and bioactivities

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    MUDASIR DAR

    2012-07-01

    Full Text Available Rai M, Gade A, Rathod D, Dar M, Varma A. 2012. Review: Mycoendophytes in medicinal plants: Diversity and bioactivities. Nusantara Bioscience 4: 86-96. Endophytes are microorganisms that reside in internal tissues of living plants without causing any negative effect. These offer tremendous potential for the exploitation of novel and eco-friendly secondary metabolites used in medicine, the pharmaceutical industry and agriculture. The present review is focused on diversity of endophytes, current national and international bioactive secondary metabolite scenario and future prospects. Endophytic fungi as novel source of potentially useful medicinal compounds are discussed along with the need to search for new and more effective agents from endophytes to combat disease problems.

  16. Urban Bird Diversity and Landscape Complexity: Species-environment Associations Along a Multiscale Habitat Gradient

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    Kathy Martin

    2003-07-01

    Full Text Available For birds in urban environments, the configuration of local habitat within the landscape may be as critical as the composition of the local habitat itself. We examined the relative importance of environmental attributes (e.g., tree cover, composition, and number of tree species measured at different spatial scales in relation to urban bird species richness and abundance. We expected that some bird species and nesting guilds would have a closer association with landscape-level features (within 1000 m, such as proximity to large forested areas, than with local-scale habitat measures (within 50 m. To investigate this, avian community data were collected at 285 point-count stations in 1997 and 1998 along four roadside transects located in Vancouver and Burnaby, British Columbia, Canada. Transects (5–25 km in length bisected three large parks (>324 ha and proceeded along residential streets in urban and suburban areas. In total, 48 bird species were observed, including 25 common species. Species richness declined in relation to a gradient of increasing urbanization, as measured by local- and landscape-level habitat features. We further examined the significance and importance of local- vs. landscape-level habitat attributes using logistic regression and found that both scales explained the presence/absence distributions of residential birds. Local-scale habitat features such as large coniferous trees, berry-producing shrubs, and freshwater streams were of particular importance in estimating the likelihood of finding bird species. Landscape measures, particularly forest cover (within 500 m and park area (measured at different scales as a function of distance from point-count stations significantly improved likelihood estimations based solely on local-scale habitat features. Our results suggest that both local- and landscape-scale resources were important in determining the distribution of birds in urban areas. Parks, reserves, and the surrounding

  17. Distribution and diversity of Tardigrada along altitudinal gradients in the Hornsund, Spitsbergen (Arctic

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    Krzysztof Zawierucha

    2015-02-01

    Full Text Available Two transects were established and sampled along altitudinal gradients on the slopes of Ariekammen (77°01′N; 15°31′E and Rotjesfjellet (77°00′N; 15°22′E in Hornsund, Spitsbergen. In total 59 moss, lichen, liverwort and mixed moss–lichen samples were collected and 33 tardigrade species of Hetero- and Eutardigrada were found. The α diversity ranged from 1 to 8 per sample; the estimated number of species based on all analysed samples was 52±17 for the Chao 2 estimator and 41 for the incidence-based coverage estimator. According to the results of detrended canonical correspondence analysis, altitude and type of substratum were the most important factors influencing tardigrade communities in the investigated area. Macrobiotus crenulatus, M. hufelandi hufelandi and Hypsibius pallidus dominated in the lower elevations, whereas Echiniscus wendti and E. merokensis merokensis prevailed in samples from higher plots. Macrobiotus islandicus islandicus was collected most often from mosses collected from rock whereas Isohypsibius coulsoni from mosses collected from soil. Analyses of covariance were employed to test for differences in species richness between the transects in relation to altitude. Contrary to expectations, there were significant differences in species richness between the transects, but richness was not significantly related to altitude. Interestingly, significant effects of colonies of seabirds, little auk (Alle alle, on the tardigrades communities were detected. Additionally, in one of the samples first ever males of Milnesium asiaticum were found. Their measurements and microphotographs are provided herein.

  18. Herbivores and nutrients control grassland plant diversity via light limitation.

    Energy Technology Data Exchange (ETDEWEB)

    Borer, Elizabeth T. [Department of Ecology, Evolution, and Behavior, University of Minnesota; et al, et al

    2014-01-01

    Human alterations to nutrient cycles1,2 and herbivore communities3–7 are affecting global biodiversity dramatically2. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  19. Inter-varietal interactions among plants in genotypically diverse mixtures tend to decrease herbivore performance.

    Science.gov (United States)

    Grettenberger, Ian M; Tooker, John F

    2016-09-01

    Much research has explored the effects of plant species diversity on herbivore populations, but far less has considered effects of plant genotypic diversity, or how abiotic stressors, like drought, can modify effects. Mechanisms by which plant genotypic diversity affects herbivore populations remain largely unresolved. We used greenhouse studies with a model system of wheat (Triticum aestivum L.) and bird cherry-oat aphid (Rhopalosiphum padi L.) to determine whether the genotypic diversity of a plant's neighborhood influences performance and fitness of herbivores on a focal plant and if drought changes the influence of neighborhood diversity. Taken across all varieties we tested, plant-plant interactions in diverse neighborhoods reduced aphid performance and generated associational resistance, although effects on aphids depended on variety identity. In diverse mixtures, drought stress greatly diminished the genotypic diversity-driven reduction in aphid performance. Neighborhood diversity influenced mother aphid size, and appeared to partially explain how plant-plant interactions reduced the number of offspring produced in mixtures. Plant size did not mediate effects on aphid performance, although neighborhood diversity reduced plant mass across varieties and watering treatments. Our results suggest inter-varietal interactions in genotypic mixtures can affect herbivore performance in the absence of herbivore movement and that abiotic stress may diminish any effects. Accounting for how neighborhood diversity influences resistance of an individual plant to herbivores will help aid development of mixtures of varieties for managing insect pests and clarify the role of plant genotypic diversity in ecosystems.

  20. Disturbance gradient shows logging affects plant functional groups more than fire.

    Science.gov (United States)

    Blair, David P; McBurney, Lachlan M; Blanchard, Wade; Banks, Sam C; Lindenmayer, David B

    2016-10-01

    Understanding the impacts of natural and human disturbances on forest biota is critical for improving forest management. Many studies have examined the separate impacts on fauna and flora of wildfire, conventional logging, and salvage logging, but empirical comparisons across a broad gradient of simultaneous disturbances are lacking. We quantified species richness and frequency of occurrence of vascular plants, and functional group responses, across a gradient of disturbances that occurred concurrently in 2009 in the mountain ash forests of southeastern Australia. Our study encompassed replicated sites in undisturbed forest (~70 yr post fire), forest burned at low severity, forest burned at high severity, unburned forest that was clearcut logged, and forest burned at high severity that was clearcut salvage logged post-fire. All sites were sampled 2 and 3 yr post fire. Mean species richness decreased across the disturbance gradient from 30.1 species/site on low-severity burned sites and 28.9 species/site on high-severity burned sites, to 25.1 species/site on clearcut sites and 21.7 species/site on salvage logged sites. Low-severity burned sites were significantly more species-rich than clearcut sites and salvage logged sites; high-severity burned sites supported greater species richness than salvage logged sites. Specific traits influenced species' sensitivity to disturbance. Resprouting species dominated undisturbed mountain ash forests, but declined significantly across the gradient. Fern and midstory trees decreased significantly in frequency of occurrence across the gradient. Ferns (excluding bracken) decreased from 34% of plants in undisturbed forest to 3% on salvage logged sites. High-severity burned sites supported a greater frequency of occurrence and species richness of midstory trees compared to clearcut and salvage logged sites. Salvage logging supported fewer midstory trees than any other disturbance category, and were distinctly different from

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

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    Kari Klanderud

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

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

    Science.gov (United States)

    Klanderud, Kari; Vandvik, Vigdis; Goldberg, Deborah

    2015-01-01

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

  3. Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China

    Directory of Open Access Journals (Sweden)

    Minyi Huang

    2016-03-01

    Full Text Available Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G, building patch (B, mature patch (M and degenerate patch (D. To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1 Different species (or functional groups had distinct presence frequencies in the four different patch types along the altitudinal gradient; (2 Some species or functional groups (species groups sharing similar traits and responses to the environment only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3 Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former; (4 The maximum numbers of species and two diversity indices (D′ and H′ were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

  4. Plant diversity associated with pools in natural and restored peatlands

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    N. Fontaine

    2007-06-01

    Full Text Available This study describes plant assemblages associated with the edges of peatland pools. We conducted inventories in six natural peatlands in the province of Québec (Canada in order to measure the contribution of pools to species diversity in climatic regions where peatlands are used for peat extraction. We also carried out vegetation surveys in a peatland that has been restored after peat extraction/harvesting to determine whether pool vegetation establishes along the edges of created pools when dry surface restoration techniques only are used. Pools enhanced plant species richness in natural peatlands. Around created pools, species associated with natural pools were still absent, and non-bog species were present, six years after restoration. On this basis, we emphasise the importance of preserving natural peatlands with pools. In order to restore fully the plant diversity associated with peatlands at harvested sites, it may be necessary to modify pool excavation techniques so that created pools resemble more closely those in natural peatlands. Active introduction of the plant species or communities associated with natural pools may also be needed; candidate species for North America include Andromeda glaucophylla, Cladopodiella fluitans, Carex limosa, Eriophorum virginicum, Rhynchospora alba and Sphagnum cuspidatum.

  5. Plant Growth Promotion Potential Is Equally Represented in Diverse Grapevine Root-Associated Bacterial Communities from Different Biopedoclimatic Environments

    Directory of Open Access Journals (Sweden)

    Ramona Marasco

    2013-01-01

    Full Text Available Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P=0.03 and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23% presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%, insoluble phosphate solubilisation (61%, and ammonia production (70%. The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root.

  6. Plant leaf wax biomarkers capture gradients in hydrogen isotopes of precipitation from the Andes and Amazon

    Science.gov (United States)

    Feakins, Sarah J.; Bentley, Lisa Patrick; Salinas, Norma; Shenkin, Alexander; Blonder, Benjamin; Goldsmith, Gregory R.; Ponton, Camilo; Arvin, Lindsay J.; Wu, Mong Sin; Peters, Tom; West, A. Joshua; Martin, Roberta E.; Enquist, Brian J.; Asner, Gregory P.; Malhi, Yadvinder

    2016-06-01

    Plant leaf waxes have been found to record the hydrogen isotopic composition of precipitation and are thus used to reconstruct past climate. To assess how faithfully they record hydrological signals, we characterize leaf wax hydrogen isotopic compositions in forest canopy trees across a highly biodiverse, 3 km elevation range on the eastern flank of the Andes. We sampled the dominant tree species and assessed their relative abundance in the tree community. For each tree we collected xylem and leaf samples for analysis of plant water and plant leaf wax hydrogen isotopic compositions. In total, 176 individuals were sampled across 32 species and 5 forest plots that span the gradient. We find both xylem water and leaf wax δD values of individuals correlate (R2 = 0.8 and R2 = 0.3 respectively) with the isotopic composition of precipitation (with an elevation gradient of -21‰ km-1). Minimal leaf water enrichment means that leaf waxes are straightforward recorders of the isotopic composition of precipitation in wet climates. For these tropical forests we find the average fractionation between source water and leaf wax for C29n-alkanes, -129 ± 2‰ (s.e.m., n = 136), to be indistinguishable from that of temperate moist forests. For C28n-alkanoic acids the average fractionation is -121 ± 3‰ (s.e.m., n = 102). Sampling guided by community assembly within forest plots shows that integrated plant leaf wax hydrogen isotopic compositions faithfully record the gradient of isotopes in precipitation with elevation (R2 = 0.97 for n-alkanes and 0.60 for n-alkanoic acids). This calibration study supports the use of leaf waxes as recorders of the isotopic composition of precipitation in lowland tropical rainforest, tropical montane cloud forests and their sedimentary archives.

  7. Plant diversity and root traits benefit physical properties key to soil function in grasslands

    NARCIS (Netherlands)

    Gould, Iain J.; Quinton, John N.; Weigelt, Alexandra; Deyn, De Gerlinde B.; Bardgett, Richard D.; Seabloom, Eric

    2016-01-01

    Plant diversity loss impairs ecosystem functioning, including important effects on soil. Most studies that have explored plant diversity effects belowground, however, have largely focused on biological processes. As such, our understanding of how plant diversity impacts the soil physical

  8. Roles of mesophyll conductance and plant functional diversities in tropical photosynthesis

    Science.gov (United States)

    Gu, L.

    2013-12-01

    Tropical photosynthesis dominates global terrestrial gross primary production (GPP) and will likely play a defining role in determining how global GPP will respond to climate change. Yet, our current understanding of biological, ecological, edaphic and environmental controls on tropical photosynthesis is poor. The overly simplistic schemes that current Earth System Models use to simulate tropical photosynthesis cannot capture the functional diversities associated with high species diversities in the tropics. New approaches that explicitly represent the functional diversities of tropical photosynthesis in Earth System Models are needed in order to realistically model responses of tropical photosynthesis to increased atmospheric CO2 concentrations and associated climate changes. To establish a basis for such approaches, we conducted intensive field measurements of leaf photosynthesis at three forest sites along a strong rainfall gradient in Panama in 2012-2013. The three sites are Parque Natural Metropolitano, Gamboa, and Parque Nacional San Lorenzo. The Parque Natural Metropolitano receives an annual precipitation of less than 1800mm and Parque Nacional San Lorenzo over 3300 mm with Gamboa in between. The three sites differ in species diversity with Parque Nacional San Lorenzo having the highest species diversity and Parque Nacional San Lorenzo the lowest. At the three contrasting sites, we measured A/Ci curves, leaf traits and leaf nutrient (N and P) contents of about 100 species. We determined mesophyll conductance with the LeafWeb approach. From these measurements, we developed practical but realistic parameterizations of functional diversities of tropical plant species at the three sites and implemented these parameterizations in the latest version of the Community Land Model. We found that mesophyll conductance is key to representing functional diversities of tropical forest species. Without it, responses of tropical photosynthesis to increased atmospheric CO2

  9. Plant traits mediate consumer and nutrient control on plant community productivity and diversity.

    Science.gov (United States)

    Eskelinen, Anu; Harrison, Susan; Tuomi, Maria

    2012-12-01

    The interactive effects of consumers and nutrients on terrestrial plant communities, and the role of plant functional traits in mediating these responses, are poorly known. We carried out a six-year full-factorial field experiment using mammalian herbivore exclusion and fertilization in two habitat types (fertile and infertile alpine tundra heaths) that differed in plant functional traits related to resource acquisition and palatability. Infertile habitats were dominated by species with traits indicative of a slow-growing strategy: high C:N ratio, low specific leaf area, and high condensed tannins. We found that herbivory counteracted the effect of fertilization on biomass, and that this response differed between the two habitats and was correlated with plant functional traits. Live biomass dominated the treatment responses in infertile habitats, whereas litter accumulation dominated the treatment responses in fertile habitats and was strongly negatively associated with resident community tannin concentration. Species richness declined under herbivore exclusion and fertilization in fertile habitats, where litter accumulation was greatest. Community means of plant C:N ratio predicted treatment effects on diversity: fertilization decreased and herbivory increased dominance in communities originally dominated by plants with high C:N, while fertilization increased and herbivory diminished dominance in communities where low C:N species were abundant. Our results highlight the close interdependence between consumer effects, soil nutrients, and plant functional traits and suggest that plant traits may provide an improved understanding of how consumers and nutrients influence plant community productivity and diversity.

  10. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India

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    AJEY KUMAR PATHAK

    2014-10-01

    Full Text Available Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India. Biodiversitas 15: 186-194.The present study describes the analysis and mapping of the different measurements of freshwater fish biodiversity of the Upper Ganges basin in the Himalayan region using spatial interpolation methods of Geographical Information System. The diversity, richness and abundance of fishes for each sampling location were determined and Kriging interpolation was applied on each fisheries measurement to predict and produce semivariogram. The semivariogarms produced were cross validated and reclassified. The reclassified maps for richness, abundance and diversity of fishes, occurrence of cold water threatened fish and abundance of important genera like Tor, Schziothorax and species were produced. The result of the Kriging produced good results and overall error in the estimation process was found significant. The cross validation of semovariograms also provided a better result with the observed data sets. Moreover, weighted overlay analysis of the reclassified raster maps of richness and abundance of fishes produced the classified raster map at different evaluation scale (0-10 qualitatively describing the gradient of species richness and abundance compositely. Similarly, the classified raster map at same evaluation scale qualitatively describing the gradient of species abundance and diversity compositely was produced and published. Further, basin wise analysis between Alaknanda/Pindar and Ganga1 sub basins showed 0.745 disparities at 0.745 distances in 2 dimensional spaces. The richness, diversity and abundance of threatened fishes among the different sampling locations were not significant (p = 0.9.

  11. Expanding Kenya's protected areas under the Convention on Biological Diversity to maximize coverage of plant diversity.

    Science.gov (United States)

    Scherer, Laura; Curran, Michael; Alvarez, Miguel

    2017-04-01

    Biodiversity is highly valuable and critically threatened by anthropogenic degradation of the natural environment. In response, governments have pledged enhanced protected-area coverage, which requires scarce biological data to identify conservation priorities. To assist this effort, we mapped conservation priorities in Kenya based on maximizing alpha (species richness) and beta diversity (species turnover) of plant communities while minimizing economic costs. We used plant-cover percentages from vegetation surveys of over 2000 plots to build separate models for each type of diversity. Opportunity and management costs were based on literature data and interviews with conservation organizations. Species richness was predicted to be highest in a belt from Lake Turkana through Mount Kenya and in a belt parallel to the coast, and species turnover was predicted to be highest in western Kenya and along the coast. Our results suggest the expanding reserve network should focus on the coast and northeastern provinces of Kenya, where new biological surveys would also fill biological data gaps. Meeting the Convention on Biological Diversity target of 17% terrestrial coverage by 2020 would increase representation of Kenya's plant communities by 75%. However, this would require about 50 times more funds than Kenya has received thus far from the Global Environment Facility. © 2016 Society for Conservation Biology.

  12. Relationships between Spatial Metrics and Plant Diversity in Constructed Freshwater Wetlands.

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    Erika C Brandt

    Full Text Available The diversity of plant species and their distribution in space are both thought to have important effects on the function of wetland ecosystems. However, knowledge of the relationships between plant species and spatial diversity remains incomplete. In this study, we investigated relationships between spatial pattern and plant species diversity over a five year period following the initial restoration of experimental wetland ecosystems. In 2003, six identical and hydrologically-isolated 0.18 ha wetland "cells" were constructed in former farmland in northeast Ohio. The systems were subjected to planting treatments that resulted in different levels of vascular plant species diversity among cells. Plant species diversity was assessed through annual inventories. Plant spatial pattern was assessed by digitizing low-altitude aerial photographs taken at the same time as the inventories. Diversity metrics derived from the inventories were significantly related to certain spatial metrics derived from the photographs, including cover type diversity and contagion. We found that wetlands with high cover type diversity harbor higher plant species diversity than wetlands with fewer types of patches. We also found significant relationships between plant species diversity and spatial patterning of patch types, but the direction of the effect differed depending on the diversity metric used. Links between diversity and spatial pattern observed in this study suggest that high-resolution aerial imagery may provide wetland scientists with a useful tool for assessing plant diversity.

  13. Relationships between Spatial Metrics and Plant Diversity in Constructed Freshwater Wetlands

    Science.gov (United States)

    Grossman, Jake J.; Allen, George A.; Benzing, David H.

    2015-01-01

    The diversity of plant species and their distribution in space are both thought to have important effects on the function of wetland ecosystems. However, knowledge of the relationships between plant species and spatial diversity remains incomplete. In this study, we investigated relationships between spatial pattern and plant species diversity over a five year period following the initial restoration of experimental wetland ecosystems. In 2003, six identical and hydrologically-isolated 0.18 ha wetland “cells” were constructed in former farmland in northeast Ohio. The systems were subjected to planting treatments that resulted in different levels of vascular plant species diversity among cells. Plant species diversity was assessed through annual inventories. Plant spatial pattern was assessed by digitizing low-altitude aerial photographs taken at the same time as the inventories. Diversity metrics derived from the inventories were significantly related to certain spatial metrics derived from the photographs, including cover type diversity and contagion. We found that wetlands with high cover type diversity harbor higher plant species diversity than wetlands with fewer types of patches. We also found significant relationships between plant species diversity and spatial patterning of patch types, but the direction of the effect differed depending on the diversity metric used. Links between diversity and spatial pattern observed in this study suggest that high-resolution aerial imagery may provide wetland scientists with a useful tool for assessing plant diversity. PMID:26296205

  14. Endophytic Fungal Diversity in Medicinal Plants of Western Ghats, India

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    Monnanda Somaiah Nalini

    2014-01-01

    Full Text Available Endophytes constitute an important component of microbial diversity, and in the present investigation, seven plant species with rich ethnobotanical uses representing six families were analyzed for the presence of endophytic fungi from their natural habitats during monsoon (May/June and winter (November/December seasons of 2007. Fungal endophytes were isolated from healthy plant parts such as stem, root, rhizome, and inflorescence employing standard isolation methods. One thousand five hundred and twenty-nine fungal isolates were obtained from 5200 fragments. Stem fragments harbored more endophytes (80.37% than roots (19.22%. 31 fungal taxa comprised of coelomycetes (65%, hyphomycetes (32%, and ascomycetes (3%. Fusarium, Acremonium, Colletotrichum, Chaetomium, Myrothecium, Phomopsis, and Pestalotiopsis spp. were commonly isolated. Diversity indices differed significantly between the seasons (P<0.001. Species richness was greater for monsoon isolations than winter. Host specificity was observed for few fungal endophytes. UPGMA cluster analysis grouped the endophytes into distinct clusters on the basis of genetic distance. This study is the first report on the diversity and host-specificity of endophytic fungal taxa were from the semi evergreen forest type in Talacauvery subcluster of Western Ghats.

  15. Floristic diversity analysis along a fragmentation gradients: a case study of beech forests in the Molisean Appenines (southern Italy

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    Frate L

    2011-11-01

    Full Text Available The process of fragmentation of natural habitats is increasing exponentially worldwide and represents one of the foremost threats to biological diversity. Forest fragmentation is considered to heavily affect the demographic and genetic structure of forest plant populations. Habitat fragmentation is a landscape process occurring when areas of continuous habitat are broken into smaller and discontinuous patches. In this paper we analyzed the effects of fragmentation on vascular plant diversity of Fagus sylvatica forest in central Italy (habitat of Community interest -92/43/ECC- “Appenine beech forests with Taxus and Ilex” - cod. 9210*. First, by integrating five parameters that describe beech forest patches structure (patch area, perimeter, shape index, corea area, euclidean nearest neighbor we identified three levels of fragmentation: high, medium and absent. Then the vascular plants of each level of fragmentation were sampled following a random stratified design. The diversity of vascular plant species was analyzed considering two species groups: all sampled species and “diagnostic” species of the habitat 9210* (sensu Directive 92/43/ECC. We compared the biodiversity patterns of the different fragmentation levels by using rarefaction curves and Rényi’s profiles. We also tested the significance of the founded differences by a bootstrapping procedure. The diversity pattern of the two species groups (diagnostics and all species showed two opposite trends. As the diversity of the entire pool of species increased on fragmented beech forests the diversity of the diagnostic group decreased. The differences between diversity values of high and low fragmentation levels resulted significant. Our results emphasize the existence of two diagnostic species: Cardamine kitaibelii and Paris quadrifolia that are indicators of not fragmented beech forests. Additionally the diversity pattern of the diagnostics species allow us to propose them as

  16. DIVERSITY AND SIMILARITY OF LICHEN FLORAS OF COUNTRIES ALONG A SOUTH-NORTH GRADIENT FROM ITALY TO GREENLAND

    OpenAIRE

    H. BULTMANN

    2010-01-01

    Species diversities and similarities of lichen floras from Italy via Austria, Germany, Denmark, Finland, Sweden and Norway to Greenland are compared for the complete floras and separately for bark, wood, rock and soil, the latter two also for acidic and calcareous. Lichen species diversity declines about 15% from Italy to Norway but 50% from Italy to Greenland, a much lower percentage than for vascular plants (92%!). The Sørensen coefficient and an NMDS-ordination display geographi...

  17. Mean Annual Precipitation Explains Spatiotemporal Patterns of Cenozoic Mammal Beta Diversity and Latitudinal Diversity Gradients in North America

    OpenAIRE

    2014-01-01

    Spatial diversity patterns are thought to be driven by climate-mediated processes. However, temporal patterns of community composition remain poorly studied. We provide two complementary analyses of North American mammal diversity, using (i) a paleontological dataset (2077 localities with 2493 taxon occurrences) spanning 21 discrete subdivisions of the Cenozoic based on North American Land Mammal Ages (36 Ma – present), and (ii) climate space model predictions for 744 extant mammals under eig...

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

    NARCIS (Netherlands)

    Kostenko, O.; Grootemaat, S.; Putten, van der 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

  19. DIVERSITY AND SIMILARITY OF LICHEN FLORAS OF COUNTRIES ALONG A SOUTH-NORTH GRADIENT FROM ITALY TO GREENLAND

    Directory of Open Access Journals (Sweden)

    H. BULTMANN

    2010-04-01

    Full Text Available Species diversities and similarities of lichen floras from Italy via Austria, Germany, Denmark, Finland, Sweden and Norway to Greenland are compared for the complete floras and separately for bark, wood, rock and soil, the latter two also for acidic and calcareous. Lichen species diversity declines about 15% from Italy to Norway but 50% from Italy to Greenland, a much lower percentage than for vascular plants (92%!. The Sørensen coefficient and an NMDS-ordination display geographic groups well: Italy, Austria and Germany, Finland, Sweden and Norway and finally Greenland. Denmark as the only country without mountains lacks saxicolous species and differs from the other countries. About half of the lichen species grow on rock, followed by bark, except for Greenland, there soil. Diversity and composition of lichen floras on bark and wood are rather homogeneous from Italy to Scandinavia, on soil even from Italy to Greenland. Diversity is higher on acidic than calcareous rock and soil, a contrast to observations from vascular plants. The diversity loss in “southern” calciphytic species in the northern countries is compensated by additional “nordic” species on acidic substrate. From Greenland even more acidophytic terricolous lichen species are known than from Italy. The reasons for the pH dependent diversity patterns are, same as for vascular plants, not known.

  20. DIVERSITY AND SIMILARITY OF LICHEN FLORAS OF COUNTRIES ALONG A SOUTH-NORTH GRADIENT FROM ITALY TO GREENLAND

    Directory of Open Access Journals (Sweden)

    H. BULTMANN

    2010-01-01

    Full Text Available Species diversities and similarities of lichen floras from Italy via Austria, Germany, Denmark, Finland, Sweden and Norway to Greenland are compared for the complete floras and separately for bark, wood, rock and soil, the latter two also for acidic and calcareous. Lichen species diversity declines about 15% from Italy to Norway but 50% from Italy to Greenland, a much lower percentage than for vascular plants (92%!. The Sørensen coefficient and an NMDS-ordination display geographic groups well: Italy, Austria and Germany, Finland, Sweden and Norway and finally Greenland. Denmark as the only country without mountains lacks saxicolous species and differs from the other countries. About half of the lichen species grow on rock, followed by bark, except for Greenland, there soil. Diversity and composition of lichen floras on bark and wood are rather homogeneous from Italy to Scandinavia, on soil even from Italy to Greenland. Diversity is higher on acidic than calcareous rock and soil, a contrast to observations from vascular plants. The diversity loss in “southern” calciphytic species in the northern countries is compensated by additional “nordic” species on acidic substrate. From Greenland even more acidophytic terricolous lichen species are known than from Italy. The reasons for the pH dependent diversity patterns are, same as for vascular plants, not known.

  1. The Future of Vascular Plant Diversity Under Four Global Scenarios

    Directory of Open Access Journals (Sweden)

    Detlef P. van Vuuren

    2006-12-01

    Full Text Available Biodiversity is of crucial importance for ecosystem functioning and human well-being. Using quantitative projections of changes in land use and climate from the four Millennium Ecosystem Assessment (MA scenarios, we project that reduction of habitat by year 2050 will result in a loss of global vascular plant diversity ranging from 7-24% relative to 1995, after populations have reached equilibrium with the reduced habitat. This range includes both the impact of different scenarios and uncertainty in the SAR relationship. Biomes projected to lose the most species are warm mixed forest, savannahs, shrub, tropical forest, and tropical woodlands. In the 2000-2050 period, land-use change contributes more on a global scale to species diversity loss than does climate change, 7-13% vs. 2-4% loss at equilibrium for different scenarios, respectively. However, after 2050, climate change will become increasingly important.

  2. Dominant plant taxa predict plant productivity responses to CO2 enrichment across precipitation and soil gradients

    Science.gov (United States)

    Fay, Philip A.; Newingham, Beth A.; Polley, H. Wayne; Morgan, Jack A.; LeCain, Daniel R.; Nowak, Robert S.; Smith, Stanley D.

    2015-01-01

    The Earth's atmosphere will continue to be enriched with carbon dioxide (CO2) over the coming century. Carbon dioxide enrichment often reduces leaf transpiration, which in water-limited ecosystems may increase soil water content, change species abundances and increase the productivity of plant communities. The effect of increased soil water on community productivity and community change may be greater in ecosystems with lower precipitation, or on coarser-textured soils, but responses are likely absent in deserts. We tested correlations among yearly increases in soil water content, community change and community plant productivity responses to CO2 enrichment in experiments in a mesic grassland with fine- to coarse-textured soils, a semi-arid grassland and a xeric shrubland. We found no correlation between CO2-caused changes in soil water content and changes in biomass of dominant plant taxa or total community aboveground biomass in either grassland type or on any soil in the mesic grassland (P > 0.60). Instead, increases in dominant taxa biomass explained up to 85 % of the increases in total community biomass under CO2 enrichment. The effect of community change on community productivity was stronger in the semi-arid grassland than in the mesic grassland, where community biomass change on one soil was not correlated with the change in either the soil water content or the dominant taxa. No sustained increases in soil water content or community productivity and no change in dominant plant taxa occurred in the xeric shrubland. Thus, community change was a crucial driver of community productivity responses to CO2 enrichment in the grasslands, but effects of soil water change on productivity were not evident in yearly responses to CO2 enrichment. Future research is necessary to isolate and clarify the mechanisms controlling the temporal and spatial variations in the linkages among soil water, community change and plant productivity responses to CO2 enrichment. PMID

  3. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotides...... probes (monoclonal antibodies mAbs and carbohydrate binding modules, CBMs) to rapidly profile polysaccharides across a sample set. During my PhD I have further developed the CoMPP technique and used it for cell wall analysis within the context of a variety of applied and fundamental projects. The data...... produced has provided new insight into cell wall evolution and biosynthesis and has contributed to the commercial development of cell wall materials. A major focus of the work has been the wide scale sampling of cell wall diversity across the plant kingdom, from unicellular algae to highly evolved...

  4. Plant diterpene synthases: exploring modularity and metabolic diversity for bioengineering.

    Science.gov (United States)

    Zerbe, Philipp; Bohlmann, Jörg

    2015-07-01

    Plants produce thousands of diterpenoid natural products; some of which are of significant industrial value as biobased pharmaceuticals (taxol), fragrances (sclareol), food additives (steviosides), and commodity chemicals (diterpene resin acids). In nature, diterpene synthase (diTPS) enzymes are essential for generating diverse diterpene hydrocarbon scaffolds. While some diTPSs also form oxygenated compounds, more commonly, oxygenation is achieved by cytochrome P450-dependent mono-oxygenases. Recent genome-, transcriptome-, and metabolome-guided gene discovery and enzyme characterization identified novel diTPS functions that form the core of complex modular pathway systems. Insights into diterpene metabolism may translate into the development of new bioengineered microbial and plant-based production systems.

  5. Highly consistent effects of plant litter identity and functional traits on decomposition across a latitudinal gradient.

    Science.gov (United States)

    Makkonen, Marika; Berg, Matty P; Handa, I Tanya; Hättenschwiler, Stephan; van Ruijven, Jasper; van Bodegom, Peter M; Aerts, Rien

    2012-09-01

    Plant litter decomposition is a key process in terrestrial carbon cycling, yet the relative importance of various control factors remains ambiguous at a global scale. A full reciprocal litter transplant study with 16 litter species that varied widely in traits and originated from four forest sites covering a large latitudinal gradient (subarctic to tropics) showed a consistent interspecific ranking of decomposition rates. At a global scale, variation in decomposition was driven by a small subset of litter traits (water saturation capacity and concentrations of magnesium and condensed tannins). These consistent findings, that were largely independent of the varying local decomposer communities, suggest that decomposer communities show little specialisation and high metabolic flexibility in processing plant litter, irrespective of litter origin. Our results provide strong support for using trait-based approaches in modelling the global decomposition component of biosphere-atmosphere carbon fluxes. © 2012 Blackwell Publishing Ltd/CNRS.

  6. Diversity and geochemical structuring of bacterial communities along a salinity gradient in a carbonate aquifer subject to seawater intrusion.

    Science.gov (United States)

    Héry, Marina; Volant, Aurélie; Garing, Charlotte; Luquot, Linda; Elbaz Poulichet, Françoise; Gouze, Philippe

    2014-12-01

    In aquifers subject to saline water intrusion, the mixing zone between freshwater and saltwater displays strong physico-chemical gradients. Although the microbial component of these specific environments has been largely disregarded, the contribution of micro-organisms to biogeochemical reactions impacting water geochemistry has previously been conjectured. The objective of this study was to characterize and compare bacterial community diversity and composition along a vertical saline gradient in a carbonate coastal aquifer using high throughput sequencing of 16S rRNA genes. At different depths of the mixing zone, stable geochemical and hydrological conditions were associated with autochthonous bacterial communities harboring clearly distinct structures. Diversity pattern did not follow the salinity gradient, although multivariate analysis indicated that salinity was one of the major drivers of bacterial community composition, with organic carbon, pH and CO2 partial pressure. Correlation analyses between the relative abundance of bacterial taxa and geochemical parameters suggested that rare taxa may contribute to biogeochemical processes taking place at the interface between freshwater and saltwater. Bacterial respiration or alternative metabolisms such as sulfide oxidation or organic acids production may be responsible for the acidification and the resulting induced calcite dissolution observed at a specific depth of the mixing zone.

  7. Facilitating adaptation in montane plants to changing precipitation along an elevation gradient

    Science.gov (United States)

    Hess, Steve; Leopold, Christina

    2017-01-01

    Montane plant communities throughout the world have responded to changes in precipitation and temperature regimes by shifting ranges upward in elevation. Continued warmer, drier climate conditions have been documented and are projected to increase in high-elevation areas in Hawai‘i, consistent with climate change effects reported in other environments throughout the world. Organisms that cannot disperse or adapt biologically to projected climate scenarios in situ may decrease in distributional range and abundance over time. Restoration efforts will need to accommodate future climate change and account for the interactive effects of existing invasive species to ensure long-term persistence. As part of a larger, ongoing restoration effort, we hypothesized that plants from a lower-elevation forest ecotype would have higher rates of survival and growth compared to high-elevation forest conspecifics when grown in common plots along an elevation gradient. We monitored climate conditions at planting sites to identify whether temperature or rainfall influenced survival and growth after 20 weeks. We found that origin significantly affected survival in only one of three native montane species, Dodonaea viscosa. Contrary to our hypothesis, 75.2% of seedlings from high-elevation origin survived in comparison to 58.7% of seedlings from low elevation across the entire elevation gradient. Origin also influenced survival in linearized mixed models that controlled for temperature, precipitation, and elevation in D. viscosa and Chenopodium oahuense. Only C. oahuense seedlings had similar predictors of growth and survival. There were no common patterns of growth or survival between species, indicating that responses to changing precipitation and emperature regimes varied between montane plant species. Results also suggest that locally sourced seed is important to ensure highest survival at restoration sites. Further experimentation on larger spatial and temporal scales is necessary

  8. Deforestation and plant diversity of Madagascar's littoral forests.

    Science.gov (United States)

    Consiglio, Trisha; Schatz, George E; McPherson, Gordon; Lowry, Porter P; Rabenantoandro, Johny; Rogers, Zachary S; Rabevohitra, Raymond; Rabehevitra, David

    2006-12-01

    Few studies have attempted to quantify the reduction or document the floristic composition of forests in Madagascar. Thus, we focused specifically on deforestation and plant diversity in Madagascar's eastern littoral community. We used a data set of approximately 13,500 specimen records compiled from both historical and contemporary collections resulting from recent intensive inventory efforts to enumerate total plant species richness and to analyze the degree of endemism within littoral forests. Change in littoral forest cover from original to current extent was estimated using geographical information systems tools, remote sensing data (satellite imagery and low-elevation digital photography), and environmental data layers. Of the original littoral forest only 10.3% remains in the form of small forest parcels, and only 1.5% of these remaining fragments are included within the existing protected-areas network. Additionally, approximately 13% of Madagascar's total native flora has been recorded from these forests that originally occupied land surface, and over 25% of the 1535 plant species known from littoral forests are endemic to this community. Given the ongoing pressure from human settlement along Madagascar's eastern coast, protection of the remaining forest fragments is critical for their survival. Fifteen of the largest intact littoral forest fragments we identified, collectively representing 41.5% of remaining littoral forest, are among priority sites recommended to the government of Madagascar for plant conservation and incorporation into the protected-areas network.

  9. Plant and algal cell walls: diversity and functionality.

    Science.gov (United States)

    Popper, Zoë A; Ralet, Marie-Christine; Domozych, David S

    2014-10-01

    Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore,wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes ( plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every aspect of plant

  10. Tree aboveground carbon storage correlates with environmental gradients and functional diversity in a tropical forest.

    Science.gov (United States)

    Shen, Yong; Yu, Shixiao; Lian, Juyu; Shen, Hao; Cao, Honglin; Lu, Huanping; Ye, Wanhui

    2016-06-09

    Tropical forests play a disproportionately important role in the global carbon (C) cycle, but it remains unclear how local environments and functional diversity regulate tree aboveground C storage. We examined how three components (environments, functional dominance and diversity) affected C storage in Dinghushan 20-ha plot in China. There was large fine-scale variation in C storage. The three components significantly contributed to regulate C storage, but dominance and diversity of traits were associated with C storage in different directions. Structural equation models (SEMs) of dominance and diversity explained 34% and 32% of variation in C storage. Environments explained 26-44% of variation in dominance and diversity. Similar proportions of variation in C storage were explained by dominance and diversity in regression models, they were improved after adding environments. Diversity of maximum diameter was the best predictor of C storage. Complementarity and selection effects contributed to C storage simultaneously, and had similar importance. The SEMs disengaged the complex relationships among the three components and C storage, and established a framework to show the direct and indirect effects (via dominance and diversity) of local environments on C storage. We concluded that local environments are important for regulating functional diversity and C storage.

  11. Functional traits reveal the expansion and packing of ecological niche space underlying an elevational diversity gradient in passerine birds.

    Science.gov (United States)

    Pigot, Alex L; Trisos, Christopher H; Tobias, Joseph A

    2016-01-13

    Variation in species richness across environmental gradients may be associated with an expanded volume or increased packing of ecological niche space. However, the relative importance of these alternative scenarios remains unknown, largely because standardized information on functional traits and their ecological relevance is lacking for major diversity gradients. Here, we combine data on morphological and ecological traits for 523 species of passerine birds distributed across an Andes-to-Amazon elevation gradient. We show that morphological traits capture substantial variation in species dietary (75%) and foraging niches (60%) when multiple independent trait dimensions are considered. Having established these relationships, we show that the 14-fold increase in species richness towards the lowlands is associated with both an increased volume and density of functional trait space. However, we find that increases in volume contribute little to changes in richness, with most (78%) lowland species occurring within the range of trait space occupied at high elevations. Taken together, our results suggest that high species richness is mainly associated with a denser occupation of functional trait space, implying an increased specialization or overlap of ecological niches, and supporting the view that niche packing is the dominant trend underlying gradients of increasing biodiversity towards the lowland tropics. © 2016 The Author(s).

  12. Assessment of the genotypic diversity of antibiotic-producing Pseudomonas species in the rhizosphere by denaturing gradient gel electrophoresis

    NARCIS (Netherlands)

    Bergsma-Vlami, M.; Prins, M.E.; Staats, M.; Raaijmakers, J.M.

    2005-01-01

    The genotypic diversity of antibiotic-producing Pseudomonas spp. provides an enormous resource for identifying strains that are highly rhizosphere competent and superior for biological control of plant diseases. In this study, a simple and rapid method was developed to determine the presence and gen

  13. Diversity of culturable thermo-resistant aquatic bacteria along an environmental gradient in Cuatro Ciénegas, Coahuila, México.

    Science.gov (United States)

    Cerritos, René; Eguiarte, Luis E; Avitia, Morena; Siefert, Janet; Travisano, Michael; Rodríguez-Verdugo, Alejandra; Souza, Valeria

    2011-02-01

    At the desert oasis of Cuatro Ciénegas in Coahuila, México, more than 300 oligotrophic pools can be found and a large number of endemic species of plants and animals. The most divergent taxa of diatoms, snail and fishes are located in the Churince hydrological system, where we analyzed the local diversification of cultivable Firmicutes and Actinobacteria. The Churince hydrological system is surrounded by gypsum dunes and has a strong gradient for salinity, temperature, pH and dissolved oxygen. In August 2003, surface water samples were taken in 10 sites along the Churince system together with the respective environmental measurements. 417 thermo-resistant bacteria were isolated and DNA was extracted to obtain their BOX-PCR fingerprints, revealing 55 different patterns. In order to identify similarities and differences in the diversity of the various sampling sites, an Ordination Analysis was applied using Principal Component Analysis. This analysis showed that conductivity is the environmental factor that explains the distribution of most of the microbial diversity. Phylogenetic reconstruction from their 16S rRNA sequences was performed for a sample of 150 isolates. Only 17 sequences had a 100% match in the Gene Bank (NCBI), representing 10 well known cosmopolitan taxa. The rest of the sequences cluster in 22 clades for Firmicutes and another 22 clades for Actinobacteria, supporting the idea of high diversity and differentiation for this site.

  14. Diversity and composition of demersal fishes along a depth gradient assessed by baited remote underwater stereo-video.

    Directory of Open Access Journals (Sweden)

    Vincent Zintzen

    Full Text Available BACKGROUND: Continental slopes are among the steepest environmental gradients on earth. However, they still lack finer quantification and characterisation of their faunal diversity patterns for many parts of the world. METHODOLOGY/PRINCIPAL FINDINGS: Changes in fish community structure and diversity along a depth gradient from 50 to 1200 m were studied from replicated stereo baited remote underwater video deployments within each of seven depth zones at three locations in north-eastern New Zealand. Strong, but gradual turnover in the identities of species and community structure was observed with increasing depth. Species richness peaked in shallow depths, followed by a decrease beyond 100 m to a stable average value from 700 to 1200 m. Evenness increased to 700 m depth, followed by a decrease to 1200 m. Average taxonomic distinctness △(+ response was unimodal with a peak at 300 m. The variation in taxonomic distinctness Λ(+ first decreased sharply from 50 to 300 m, then increased beyond 500 m depth, indicating that species from deep samples belonged to more distant taxonomic groups than those from shallow samples. Fishes with northern distributions progressively decreased in their proportional representation with depth whereas those with widespread distributions increased. CONCLUSIONS/SIGNIFICANCE: This study provides the first characterization of diversity patterns for bait-attracted fish species on continental slopes in New Zealand and is an imperative primary step towards development of explanatory and predictive ecological models, as well as being fundamental for the implementation of efficient management and conservation strategies for fishery resources.

  15. [Distribution and diversity of springtails (Hexapoda: Collembola) on the altitudinal gradient of a temperate forest in Mexico].

    Science.gov (United States)

    García-Gómez, Arturo; Castaño-Meneses, Gabriela; Palacios-Vargas, José G

    2011-03-01

    Mountain ecosystems have shown slow mineralization activity due to weather conditions, and to some groups with arthropods with special roles. The Collembola is an important group for litter fragmentation, showing different distribution patterns. The objective of the present study was to determine the diversity of Collembola along a volcano altitudinal gradient. For this, four sampling expeditions evaluated four altitudinal levels (I = 2 753, II = 3 015, III = 3 250 and IV = 3 687 masl) in Iztaccihuatl Volcano, from November 2003, and March, June and August 2004. Shannon diversity (H'), Pielou evenness (J') and Simpson dominance (1/lambda) indices were calculated. The similarity between the associations of springtails between the sampling sites was evaluated by a cluster analysis using the Pearson correlation coefficient, as distance and the unpaired arithmetic averages (UPGMA) as amalgamation method. A total of 24 075 springtails, distributed in 12 families, 46 genera and 86 species was collected. The higher species abundance was found at the altitudinal area II. The lowest diversity value was recorded in IV, while the higher diversity values were found in III. Significant differences between Shannon indices were found between zones II-III (t(0.01, 187) = 4.11, p seasonal variation in springtail abundances was not found, but it was observed that, the lower altitude (I) resulted more homogeneous along the studied period, followed by level II and III. There is a particular assemblage of springtails community in each altitudinal area studied; in general, the sites with low slope resulted more diverse in Collembola communities. These results show that there are important factors such as altitude, vegetation type and microhabitat heterogeneity that may affect the distribution of springtails communities along an altitudinal gradient.

  16. Metabolic activity and genetic diversity of microbial communities inhabiting the rhizosphere of halophyton plants.

    Science.gov (United States)

    Bárány, Agnes; Szili-Kovács, Tibor; Krett, Gergely; Füzy, Anna; Márialigeti, Károly; Borsodi, Andrea K

    2014-09-01

    A preliminary study was conducted to compare the community level physiological profile (CLPP) and genetic diversity of rhizosphere microbial communities of four plant species growing nearby Kiskunság soda ponds, namely Böddi-szék, Kelemen-szék and Zab-szék. CLPP was assessed by MicroResp method using 15 different substrates while Denaturing Gradient Gel Electrophoresis (DGGE) was used to analyse genetic diversity of bacterial communities. The soil physical and chemical properties were quite different at the three sampling sites. Multivariate statistics (PCA and UPGMA) revealed that Zab-szék samples could be separated according to their genetic profile from the two others which might be attributed to the geographical location and perhaps the differences in soil physical properties. Böddi-szék samples could be separated from the two others considering the metabolic activity which could be explained by their high salt and low humus contents. The number of bands in DGGE gels was related to the metabolic activity, and positively correlated with soil humus content, but negatively with soil salt content. The main finding was that geographical location, soil physical and chemical properties and the type of vegetation were all important factors influencing the metabolic activity and genetic diversity of rhizosphere microbial communities.

  17. Termite diversity across an anthropogenic disturbance gradient in the humid forest zone of West Africa

    NARCIS (Netherlands)

    Eggleton, P.; Bignell, D.E.; Hauser, S.; Dibog, L.; Norgrove, L.; Madong, B.

    2002-01-01

    Data are presented for termite assemblages across an anthropogenic disturbance gradient in the humid forest zone of West and Central Africa. Sampling was by standardised 100 mx2 m transects in: primary forest, several ages of regenerating forest, agroforestry plots, short fallows, mixed food crop fi

  18. Diversity and distribution of Listeria monocytogenes in meat processing plants.

    Science.gov (United States)

    Martín, Belén; Perich, Adriana; Gómez, Diego; Yangüela, Javier; Rodríguez, Alicia; Garriga, Margarita; Aymerich, Teresa

    2014-12-01

    Listeria monocytogenes is a major concern for the meat processing industry because many listeriosis outbreaks have been linked to meat product consumption. The aim of this study was to elucidate L. monocytogenes diversity and distribution across different Spanish meat processing plants. L. monocytogenes isolates (N = 106) collected from food contact surfaces of meat processing plants and meat products were serotyped and then characterised by multilocus sequence typing (MLST). The isolates were serotyped as 1/2a (36.8%), 1/2c (34%), 1/2b (17.9%) and 4b (11.3%). MLST identified ST9 as the most predominant allelic profile (33% of isolates) followed by ST121 (16%), both of which were detected from several processing plants and meat products sampled in different years, suggesting that those STs are highly adapted to the meat processing environment. Food contact surfaces during processing were established as an important source of L. monocytogenes in meat products because the same STs were obtained in isolates recovered from surfaces and products. L. monocytogenes was recovered after cleaning and disinfection procedures in two processing plants, highlighting the importance of thorough cleaning and disinfection procedures. Epidemic clone (EC) marker ECI was identified in 8.5%, ECIII was identified in 2.8%, and ECV was identified in 7.5% of the 106 isolates. Furthermore, a selection of presumably unrelated ST9 isolates was analysed by multi-virulence-locus sequence typing (MVLST). Most ST9 isolates had the same virulence type (VT11), confirming the clonal origin of ST9 isolates; however, one ST9 isolate was assigned to a new VT (VT95). Consequently, MLST is a reliable tool for identification of contamination routes and niches in processing plants, and MVLST clearly differentiates EC strains, which both contribute to the improvement of L. monocytogenes control programs in the meat industry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Decreasing abundance, increasing diversity and changing structure of the wild bee community (Hymenoptera: Anthophila along an urbanization gradient.

    Directory of Open Access Journals (Sweden)

    Laura Fortel

    Full Text Available BACKGROUND: Wild bees are important pollinators that have declined in diversity and abundance during the last decades. Habitat destruction and fragmentation associated with urbanization are reported as part of the main causes of this decline. Urbanization involves dramatic changes of the landscape, increasing the proportion of impervious surface while decreasing that of green areas. Few studies have investigated the effects of urbanization on bee communities. We assessed changes in the abundance, species richness, and composition of wild bee community along an urbanization gradient. METHODOLOGY/PRINCIPAL FINDINGS: Over two years and on a monthly basis, bees were sampled with colored pan traps and insect nets at 24 sites located along an urbanization gradient. Landscape structure within three different radii was measured at each study site. We captured 291 wild bee species. The abundance of wild bees was negatively correlated with the proportion of impervious surface, while species richness reached a maximum at an intermediate (50% proportion of impervious surface. The structure of the community changed along the urbanization gradient with more parasitic species in sites with an intermediate proportion of impervious surface. There were also greater numbers of cavity-nesting species and long-tongued species in sites with intermediate or higher proportion of impervious surface. However, urbanization had no effect on the occurrence of species depending on their social behavior or body size. CONCLUSIONS/SIGNIFICANCE: We found nearly a third of the wild bee fauna known from France in our study sites. Indeed, urban areas supported a diverse bee community, but sites with an intermediate level of urbanization were the most speciose ones, including greater proportion of parasitic species. The presence of a diverse array of bee species even in the most urbanized area makes these pollinators worthy of being a flagship group to raise the awareness of urban

  20. Plant-soil feedback and the maintenance of diversity in Mediterranean-climate shrublands.

    Science.gov (United States)

    Teste, François P; Kardol, Paul; Turner, Benjamin L; Wardle, David A; Zemunik, Graham; Renton, Michael; Laliberté, Etienne

    2017-01-13

    Soil biota influence plant performance through plant-soil feedback, but it is unclear whether the strength of such feedback depends on plant traits and whether plant-soil feedback drives local plant diversity. We grew 16 co-occurring plant species with contrasting nutrient-acquisition strategies from hyperdiverse Australian shrublands and exposed them to soil biota from under their own or other plant species. Plant responses to soil biota varied according to their nutrient-acquisition strategy, including positive feedback for ectomycorrhizal plants and negative feedback for nitrogen-fixing and nonmycorrhizal plants. Simulations revealed that such strategy-dependent feedback is sufficient to maintain the high taxonomic and functional diversity characterizing these Mediterranean-climate shrublands. Our study identifies nutrient-acquisition strategy as a key trait explaining how different plant responses to soil biota promote local plant diversity. Copyright © 2017, American Association for the Advancement of Science.

  1. Multiscale sampling of plant diversity: Effects of minimum mapping unit size

    Science.gov (United States)

    Stohlgren, T.J.; Chong, G.W.; Kalkhan, M.A.; Schell, L.D.

    1997-01-01

    Only a small portion of any landscape can be sampled for vascular plant diversity because of constraints of cost (salaries, travel time between sites, etc.). Often, the investigator decides to reduce the cost of creating a vegetation map by increasing the minimum mapping unit (MMU), and/or by reducing the number of vegetation classes to be considered. Questions arise about what information is sacrificed when map resolution is decreased. We compared plant diversity patterns from vegetation maps made with 100-ha, 50-ha, 2-ha, and 0.02-ha MMUs in a 754-ha study area in Rocky Mountain National Park, Colorado, United States, using four 0.025-ha and 21 0.1-ha multiscale vegetation plots. We developed and tested species-log(area) curves, correcting the curves for within-vegetation type heterogeneity with Jaccard's coefficients. Total species richness in the study area was estimated from vegetation maps at each resolution (MMU), based on the corrected species-area curves, total area of the vegetation type, and species overlap among vegetation types. With the 0.02-ha MMU, six vegetation types were recovered, resulting in an estimated 552 species (95% CI = 520-583 species) in the 754-ha study area (330 plant species were observed in the 25 plots). With the 2-ha MMU, five vegetation types were recognized, resulting in an estimated 473 species for the study area. With the 50-ha MMU, 439 plant species were estimated for the four vegetation types recognized in the study area. With the 100-ha MMU, only three vegetation types were recognized, resulting in an estimated 341 plant species for the study area. Locally rare species and keystone ecosystems (areas of high or unique plant diversity) were missed at the 2-ha, 50-ha, and 100-ha scales. To evaluate the effects of minimum mapping unit size requires: (1) an initial stratification of homogeneous, heterogeneous, and rare habitat types; and (2) an evaluation of within-type and between-type heterogeneity generated by environmental

  2. Plant functional trait diversity regulates the nonlinear response of productivity to regional climate change in Tibetan alpine grasslands

    Science.gov (United States)

    Wu, Jianshuang; Wurst, Susanne; Zhang, Xianzhou

    2016-01-01

    The biodiversity-productivity relationship is still under debate for alpine grasslands on the Tibetan Plateau. We know little about direct and indirect effects of biotic and abiotic drivers on this relationship, especially in regard to plant functional trait diversity. Here, we examine how aboveground net primary productivity (ANPP) and precipitation use efficiency (PUE) respond to climate, soil and community structure across alpine grasslands on the Northern Tibetan Plateau. We found that both ANPP and PUE showed nonlinear patterns along water availability and site altitude variation, which together accounted for 80.3% and 68.8% of variation in ANPP and PUE, respectively, by optimal generalized additive models. Functional trait divergence (FTD) and community weighted mean (CWM) of plant functional traits were as important as plant species diversity (PSD) for explaining the nonlinear productivity-climate relationship. These findings were confirmed by results from principal component analyses and structural equation models. We also found that FTD was negatively correlated with PSD across different alpine grasslands. Our results implicate: first, the combinatorial influences of temperature and precipitation gradients are important for predicting alpine grassland dynamics; second, the convergence and divergence of plant functional traits may have the potential to elucidate the effect of plant diversity on ecosystem functionality. PMID:27759112

  3. Plant functional trait diversity regulates the nonlinear response of productivity to regional climate change in Tibetan alpine grasslands.

    Science.gov (United States)

    Wu, Jianshuang; Wurst, Susanne; Zhang, Xianzhou

    2016-10-19

    The biodiversity-productivity relationship is still under debate for alpine grasslands on the Tibetan Plateau. We know little about direct and indirect effects of biotic and abiotic drivers on this relationship, especially in regard to plant functional trait diversity. Here, we examine how aboveground net primary productivity (ANPP) and precipitation use efficiency (PUE) respond to climate, soil and community structure across alpine grasslands on the Northern Tibetan Plateau. We found that both ANPP and PUE showed nonlinear patterns along water availability and site altitude variation, which together accounted for 80.3% and 68.8% of variation in ANPP and PUE, respectively, by optimal generalized additive models. Functional trait divergence (FTD) and community weighted mean (CWM) of plant functional traits were as important as plant species diversity (PSD) for explaining the nonlinear productivity-climate relationship. These findings were confirmed by results from principal component analyses and structural equation models. We also found that FTD was negatively correlated with PSD across different alpine grasslands. Our results implicate: first, the combinatorial influences of temperature and precipitation gradients are important for predicting alpine grassland dynamics; second, the convergence and divergence of plant functional traits may have the potential to elucidate the effect of plant diversity on ecosystem functionality.

  4. Plant functional trait diversity regulates the nonlinear response of productivity to regional climate change in Tibetan alpine grasslands

    Science.gov (United States)

    Wu, Jianshuang; Wurst, Susanne; Zhang, Xianzhou

    2016-10-01

    The biodiversity-productivity relationship is still under debate for alpine grasslands on the Tibetan Plateau. We know little about direct and indirect effects of biotic and abiotic drivers on this relationship, especially in regard to plant functional trait diversity. Here, we examine how aboveground net primary productivity (ANPP) and precipitation use efficiency (PUE) respond to climate, soil and community structure across alpine grasslands on the Northern Tibetan Plateau. We found that both ANPP and PUE showed nonlinear patterns along water availability and site altitude variation, which together accounted for 80.3% and 68.8% of variation in ANPP and PUE, respectively, by optimal generalized additive models. Functional trait divergence (FTD) and community weighted mean (CWM) of plant functional traits were as important as plant species diversity (PSD) for explaining the nonlinear productivity-climate relationship. These findings were confirmed by results from principal component analyses and structural equation models. We also found that FTD was negatively correlated with PSD across different alpine grasslands. Our results implicate: first, the combinatorial influences of temperature and precipitation gradients are important for predicting alpine grassland dynamics; second, the convergence and divergence of plant functional traits may have the potential to elucidate the effect of plant diversity on ecosystem functionality.

  5. Ecological Diversity in South American Mammals: Their Geographical Distribution Shows Variable Associations with Phylogenetic Diversity and Does Not Follow the Latitudinal Richness Gradient.

    Science.gov (United States)

    Fergnani, Paula Nilda; Ruggiero, Adriana

    2015-01-01

    The extent to which the latitudinal gradient in species richness may be paralleled by a similar gradient of increasing functional or phylogenetic diversity is a matter of controversy. We evaluated whether taxonomic richness (TR) is informative in terms of ecological diversity (ED, an approximation to functional diversity) and phylogenetic diversity (AvPD) using data on 531 mammal species representing South American old autochthonous (marsupials, xenarthrans), mid-Cenozoic immigrants (hystricognaths, primates) and newcomers (carnivorans, artiodactyls). If closely related species are ecologically more similar than distantly related species, AvPD will be a strong predictor of ED; however, lower ED than predicted from AvPD may be due to species retaining most of their ancestral characters, suggesting niche conservatism. This pattern could occur in tropical rainforests for taxa of tropical affinity (old autochthonous and mid-Cenozoic immigrants) and in open and arid habitats for newcomers. In contrast, higher ED than expected from AvPD could occur, possibly in association with niche evolution, in arid and open habitats for taxa of tropical affinity and in forested habitats for newcomers. We found that TR was a poor predictor of ED and AvPD. After controlling for TR, there was considerable variability in the extent to which AvPD accounted for ED. Taxa of tropical affinity did not support the prediction of ED deficit within tropical rainforests, rather, they showed a mosaic of regions with an excess of ED interspersed with zones of ED deficit within the tropics; newcomers showed ED deficit in arid and open regions. Some taxa of tropical affinity showed excess of ED in tropical desert areas (hystricognaths) or temperate semideserts (xenarthrans); newcomers showed excess of ED at cold-temperate latitudes in the Northern Hemisphere. This result suggests that extreme climatic conditions at both temperate and tropical latitudes may have promoted niche evolution in mammals.

  6. Ecological Diversity in South American Mammals: Their Geographical Distribution Shows Variable Associations with Phylogenetic Diversity and Does Not Follow the Latitudinal Richness Gradient.

    Directory of Open Access Journals (Sweden)

    Paula Nilda Fergnani

    Full Text Available The extent to which the latitudinal gradient in species richness may be paralleled by a similar gradient of increasing functional or phylogenetic diversity is a matter of controversy. We evaluated whether taxonomic richness (TR is informative in terms of ecological diversity (ED, an approximation to functional diversity and phylogenetic diversity (AvPD using data on 531 mammal species representing South American old autochthonous (marsupials, xenarthrans, mid-Cenozoic immigrants (hystricognaths, primates and newcomers (carnivorans, artiodactyls. If closely related species are ecologically more similar than distantly related species, AvPD will be a strong predictor of ED; however, lower ED than predicted from AvPD may be due to species retaining most of their ancestral characters, suggesting niche conservatism. This pattern could occur in tropical rainforests for taxa of tropical affinity (old autochthonous and mid-Cenozoic immigrants and in open and arid habitats for newcomers. In contrast, higher ED than expected from AvPD could occur, possibly in association with niche evolution, in arid and open habitats for taxa of tropical affinity and in forested habitats for newcomers. We found that TR was a poor predictor of ED and AvPD. After controlling for TR, there was considerable variability in the extent to which AvPD accounted for ED. Taxa of tropical affinity did not support the prediction of ED deficit within tropical rainforests, rather, they showed a mosaic of regions with an excess of ED interspersed with zones of ED deficit within the tropics; newcomers showed ED deficit in arid and open regions. Some taxa of tropical affinity showed excess of ED in tropical desert areas (hystricognaths or temperate semideserts (xenarthrans; newcomers showed excess of ED at cold-temperate latitudes in the Northern Hemisphere. This result suggests that extreme climatic conditions at both temperate and tropical latitudes may have promoted niche evolution in

  7. Shrines in Central Italy conserve plant diversity and large trees.

    Science.gov (United States)

    Frascaroli, Fabrizio; Bhagwat, Shonil; Guarino, Riccardo; Chiarucci, Alessandro; Schmid, Bernhard

    2016-05-01

    Sacred natural sites (SNS) are instances of biocultural landscapes protected for spiritual motives. These sites frequently host important biological values in areas of Asia and Africa, where traditional resource management is still upheld by local communities. In contrast, the biodiversity value of SNS has hardly been quantitatively tested in Western contexts, where customs and traditions have relatively lost importance due to modernization and secularization. To assess whether SNS in Western contexts retain value for biodiversity, we studied plant species composition at 30 SNS in Central Italy and compared them with a paired set of similar but not sacred reference sites. We demonstrate that SNS are important for conserving stands of large trees and habitat heterogeneity across different land-cover types. Further, SNS harbor higher plant species richness and a more valuable plant species pool, and significantly contribute to diversity at the landscape scale. We suggest that these patterns are related not only to pre-existent features, but also to traditional management. Conservation of SNS should take into account these specificities, and their cultural as well as biological values, by supporting the continuation of traditional management practices.

  8. Depth Effects on Plant Residue Decay in Diverse Soils

    Science.gov (United States)

    Gregorich, Edward; Ellert, Benjamin; Janzen, Henry; Helgason, Bobbi; Beare, Michael; Curtin, Denis

    2017-04-01

    Decay of plant residues is tied to many ecosystem functions, affecting atmospheric CO2, plant-available nutrients, microbial diversity, soil organic matter quality, among others. The rate of decay, in turn, is governed by soil type and management, location in the soil profile, and environmental variables, some of which may be changing in coming decades. Our objective in this study was to elucidate the decomposition dynamics of plant-derived C and N at different soil depths. To describe mathematically the importance of these variables across a broad scale, we established a long-term study at two sites in Canada and one site in New Zealand. At each site, labelled barley straw (13C = 10.2 atom%, 15N = 8.3 atom %; C = 37.9%; N = 0.95%; C:N = 40) was installed at 3 depths (5-10, 20-25 and 40-45 cm). Soil temperature was logged at each depth. Samples were collected at different times over 5-6 year after application of the residues. Data on recovery and kinetics of residue C and N over the experimental period will be discussed as well as 13C- PLFA results.

  9. An engine for global plant diversity: Highest evolutionary turnover and emigration in the American tropics

    Directory of Open Access Journals (Sweden)

    Alexandre eAntonelli

    2015-04-01

    Full Text Available Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the tropical biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics, as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e. Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having ‘pumped out’ more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.

  10. An engine for global plant diversity: highest evolutionary turnover and emigration in the American tropics.

    Science.gov (United States)

    Antonelli, Alexandre; Zizka, Alexander; Silvestro, Daniele; Scharn, Ruud; Cascales-Miñana, Borja; Bacon, Christine D

    2015-01-01

    Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms) between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the latitudinal biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e., Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having "pumped out" more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.

  11. Fungal disease incidence along tree diversity gradients depends on latitude in European forests

    OpenAIRE

    Nguyen, Diem; Castagneyrol, Bastien; Bruelheide, Helge; Bussotti, Filippo; Guyot, Virginie; Jactel, Hervé; Jaroszewicz, Bogdan; Valladares, Fernando; Stenlid, Jan; Boberg, Johanna

    2016-01-01

    International audience; European forests host a diversity of tree species that are increasingly threatened by fungal pathogens, which may have cascading consequences for forest ecosystems and their functioning. Previous experimental studies suggest that foliar and root pathogen abundance and disease severity decrease with increasing tree species diversity, but evidences from natural forests are rare. Here, we tested whether foliar fungal disease incidence was negatively affected by tree speci...

  12. Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients: towards a unifying framework

    Science.gov (United States)

    Soliveres, Santiago; Eldridge, David J.; Maestre, Fernando T.; Bowker, Matthew A.; Tighe, Matthew; Escudero, Adrián

    2015-01-01

    Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient equally affecting the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal richness-biomass curve, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions, and their effect on local species richness, across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we were able to see how our nurse plants (trees, shrubs and tussock grasses) not only increased local richness by expanding the niche of neighbouring species, but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum changed depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. These results can also be used to refine predictions about the response of

  13. Use of Plant Hydraulic Theory to Predict Ecosystem Fluxes Across Mountainous Gradients in Environmental Controls and Insect Disturbances

    Science.gov (United States)

    Ewers, B. E.; Pendall, E.; Reed, D. E.; Barnard, H. R.; Whitehouse, F.; Frank, J. M.; Massman, W. J.; Brooks, P. D.; Biederman, J. A.; Harpold, A. A.; Naithani, K. J.; Mitra, B.; Mackay, D. S.; Norton, U.; Borkhuu, B.

    2011-12-01

    While mountainous areas are critical for providing numerous ecosystem benefits at the regional scale, the strong gradients in environmental controls make predictions difficult. A key part of the problem is quantifying and predicting the feedback between mountain gradients and plant function which then controls ecosystem cycling. The emerging theory of plant hydraulics provides a rigorous yet simple platform from which to generate testable hypotheses and predictions of ecosystem pools and fluxes. Plant hydraulic theory predicts that plant controls over carbon, water, energy and nutrient fluxes can be derived from the limitation of plant water transport from the soil through xylem and out of stomata. In addition, the limit to plant water transport can be predicted by combining plant structure (e.g. xylem diameters or root-to-shoot ratios) and plant function (response of stomatal conductance to vapor pressure deficit or root vulnerability to cavitation). We evaluate the predictions of the plant hydraulic theory by testing it against data from a mountain gradient encompassing sagebrush steppe through subalpine forests (2700 to 3400 m). We further test the theory by predicting the carbon, water and nutrient exchanges from several coniferous trees in the same gradient that are dying from xylem dysfunction caused by blue-stain fungi carried by bark beetles. The common theme of both of these data sets is a change in water limitation caused by either changing precipitation along the mountainous gradient or lack of access to soil water from xylem-occluding fungi. Across all of the data sets which range in scale from individual plants to hillslopes, the data fit the predictions of plant hydraulic theory. Namely, there was a proportional tradeoff between the reference canopy stomatal conductance to water vapor and the sensitivity of that conductance to vapor pressure deficit that quantitatively fits the predictions of plant hydraulic theory. Incorporating this result into

  14. Plant diversity and root traits benefit physical properties key to soil function in grasslands.

    Science.gov (United States)

    Gould, Iain J; Quinton, John N; Weigelt, Alexandra; De Deyn, Gerlinde B; Bardgett, Richard D

    2016-09-01

    Plant diversity loss impairs ecosystem functioning, including important effects on soil. Most studies that have explored plant diversity effects belowground, however, have largely focused on biological processes. As such, our understanding of how plant diversity impacts the soil physical environment remains limited, despite the fundamental role soil physical structure plays in ensuring soil function and ecosystem service provision. Here, in both a glasshouse and a long-term field study, we show that high plant diversity in grassland systems increases soil aggregate stability, a vital structural property of soil, and that root traits play a major role in determining diversity effects. We also reveal that the presence of particular plant species within mixed communities affects an even wider range of soil physical processes, including hydrology and soil strength regimes. Our results indicate that alongside well-documented effects on ecosystem functioning, plant diversity and root traits also benefit essential soil physical properties.

  15. Does plant diversity benefit agroecosystems? A synthetic review.

    Science.gov (United States)

    Letourneau, Deborah K; Armbrecht, Inge; Rivera, Beatriz Salguero; Lerma, James Montoya; Carmona, Elizabeth Jiménez; Daza, Martha Constanza; Escobar, Selene; Galindo, Victor; Gutiérrez, Catalina; López, Sebastián Duque; Mejía, Jessica López; Rangel, Aleyda Maritza Acosta; Rangel, Janine Herrera; Rivera, Leonardo; Saavedra, Carlos Arturo; Torres, Alba Marina; Trujillo, Aldemar Reyes

    2011-01-01

    Predictive theory on how plant diversity promotes herbivore suppression through movement patterns, host associations, and predation promises a potential alternative to pesticide-intensive monoculture crop production. We used meta-analysis on 552 experiments in 45 articles published over the last 10 years to test if plant diversification schemes reduce herbivores and/or increase the natural enemies of herbivores as predicted by associational resistance hypotheses, the enemies hypothesis, and attraction and repellency model applications in agriculture. We found extensive support for these models with intercropping schemes, inclusion of flowering plants, and use of plants that repel herbivores or attract them away from the crop. Overall, herbivore suppression, enemy enhancement, and crop damage suppression effects were significantly stronger on diversified crops than on crops with none or fewer associated plant species. However, a relatively small, but significantly negative, mean effect size for crop yield indicated that pest-suppressive diversification schemes interfered with production, in part because of reducing densities of the main crop by replacing it with intercrops or non-crop plants. This first use of meta-analysis to evaluate the effects of diversification schemes, a potentially more powerful tool than tallies of significant positive and negative outcomes (vote-counting), revealed stronger overall effects on all parameters measured compared to previous reviews. Our analysis of the same articles used in a recent review facilitates comparisons of vote-counting and meta-analysis, and shows that pronounced results of the meta-analysis are not well explained by a reduction in articles that met its stricter criteria. Rather, compared to outcome counts, effect sizes were rarely neutral (equal to zero), and a mean effect size value for mixed outcomes could be calculated. Problematic statistical properties of vote-counting were avoided with meta-analysis, thus

  16. Challenges for Implementing Salinity Gradient Energy Power Plants at River Mouths

    Science.gov (United States)

    Alvarez-Silva, O. A.; Osoria Arias, A. F.; Winter, C.

    2016-12-01

    Salinity gradient energy (SGE) is the clean and renewable energy that can be obtained from the controlled mixing of two waters with different salt concentration. River mouths, where fresh water mixes with seawater, are manifest locations for harnessing SGE, since these systems provide the sought salinity gradients, abundant water resources worldwide and are usually located close to cities and industries. The advances in research and development of the technologies for harnessing this energy source have been huge in the last decade, however, still several challenges have to be faced before its commercial implementation at river mouths. Here we present a comprehensive analysis of the factors inherent to the river mouths that restrict the exploitation of SGE in those systems, including: (i) the effects of the stratification and the water quality on the technical suitability of the systems; (ii) the limitations on the freshwater extraction for ensuring the sustainability of the river mouths; and (iii) the effect of the spatio-temporal variability of the salinity structure on the reliability of the power plants. This analysis was carried out at global scale for almost thousand river mouths and in a more detailed scale for the Magdalena River mouth (Colombia). For the global scale, the main results show that (i) 49% of the analyzed systems are suitable locations for harnessing SGE; (ii) 625 TWh/y are extractable from river mouths worldwide; (iii) the average capacity factor of SGE plants at river mouths is 84%; and (iv) 286 systems in 64 countries have a potential capacity of 10 MW or greater. Meanwhile, for the local scale, the results show that the water quality may be the most important factor limiting the site-specific potential. Despite the limitations, the SGE generation at river mouths shows to be a promising alternative energy source in the mid-term.

  17. DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI ALONG A SAND DUNE STABILIZATION GRADIENT: A CASE STUDY AT PRAIA DE JOAQUINA, ILHA DE SANTA CATARINA, SOUTH BRAZIL

    Science.gov (United States)

    Species diversity of abuscular mycorrhizal fungi (AMF) was assessed along a dunes stabilization gradient (embyonic dune, foredune and fixed dune) at Praia da Joaquina (Joaquina Beach), Ilha de Santa Catarina. These dunes served as a case study to assess whether diversity and myc...

  18. Bacterial Diversity of Active Sludge in Wastewater Treatment Plant

    Science.gov (United States)

    Jiang, Xin; Ma, Mingchao; Li, Jun; Lu, Anhuai; Zhong, Zuoshen

    A bacterial 16S rDNA gene clone library was constructed to analyze the bacterial diversity of active sludge in Gaobeidian Wastewater Treatment Plant, Beijing. The results indicated that the bacterial diversity of active sludge was very high, and the clones could be divided into 5 different groups. The dominant bacterial community was proteobacteria, which accounted for 76.7%. The dominant succession of bacterial community were as follows: the β-proteobacteria (39.8%), the uncultured bacteria (22.33%), the γ-proteobacteria (20.15%), the α-proteobacteria (6.79%), and the σ-proteobacteria (4.85%). Nitrosomonas-like and Nitrospira-like bacteria, such as Nitrosomonas sp. (1.94%) and uncultured Nitrospirae bacterium (11.65%) were also detected, which have played important roles in ammonia and nitrite oxidisers in the system. However, they were only a little amount because of their slow growth and less competitive advantage than heterotrophic bacteria. Denitrifying bacteria like Thauera sp. was at a high percentage, which implies a strong denitrification ability; Roseomonas sp. was also detected in the clone library, which could be related to the degradation of organophosphorus pesticide.

  19. Effects of Drought on Plant Species Diversity and Productivity in the Oak Forests of Western Iran

    OpenAIRE

    Hassan Pourbabaei; Verya Rahimi; Mohammad Naghi Adel

    2014-01-01

    A severe drought in 2008 extensively damaged a variety of economic, social, agricultural and natural resources in Iran. This study investigated the effects of the 2008 drought on plant species composition, diversity and productivity in Western Iran. To this end, plant species diversity in the drought year (2008) was compared to pre-drought (2007) and post-drought (2009) diversity. The Shannon-Wiener diversity index and Margalef richness index had significant differences between years, dec...

  20. Climate interacts with soil to produce beta diversity in Californian plant communities.

    Science.gov (United States)

    Fernandez-Going, B M; Harrison, S P; Anacker, B L; Safford, H D

    2013-09-01

    Spatially distinct communities can arise through interactions and feedbacks between abiotic and biotic factors. We suggest that, for plants, patches of infertile soils such as serpentine may support more distinct communities from those in the surrounding non-serpentine matrix in regions where the climate is more productive (i.e., warmer and/or wetter). Where both soil fertility and climatic productivity are high, communities may be dominated by plants with fast-growing functional traits, whereas where either soils or climate impose low productivity, species with stress-tolerant functional traits may predominate. As a result, both species and functional composition may show higher dissimilarity between patch and matrix in productive climates. This pattern may be reinforced by positive feedbacks, in which higher plant growth under favorable climate and soil conditions leads to higher soil fertility, further enhancing plant growth. For 96 pairs of sites across a 200-km latitudinal gradient in California, we found that the species and functional dissimilarities between communities on infertile serpentine and fertile non-serpentine soils were higher in more productive (wetter) regions. Woody species had more stress-tolerant functional traits on serpentine than non-serpentine soil, and as rainfall increased, woody species functional composition changed toward fast-growing traits on non-serpentine, but not on serpentine soils. Soil organic matter increased with rainfall, but only on non-serpentine soils, and the difference in organic matter between soils was positively correlated with plant community dissimilarity. These results illustrate a novel mechanism wherein climatic productivity is associated with higher species, functional, and landscape-level dissimilarity (beta diversity).

  1. Climatic gradient and δ13C values of plants: A case study from the Himalaya

    Science.gov (United States)

    Hirave, Pranav; Sanyal, Prasanta

    2016-04-01

    Change in atmospheric conditions is believed to be responsible for the evolution of plants. In an evolving atmosphere, gymnosperms appeared during the Carboniferous Period and appearance and diversification of angiosperms occurred during the Cretaceous time. In a symbiotic environment, difference in the response of these plant types to the climatic factors can be studied for parallel correlation. To monitor plants response with the changing climatic factors, variations in plants δ13Cleaf value can be used as one of the indicators. To investigate the variation in δ13Cleaf values in response to water availability, air temperature and a change in pCO2 pressure with elevation, five gymnosperm (Cedrus deodara, Pinus wallichiana, Pinus roxburghii, Pinus gerardiana and Abies pindrow) and two angiosperm (Betula utilis and Eucalyptus globulus) species were collected along an altitude gradient in the Himalayan mountain ranges. The studied sites cover ca. 3.5 km elevation transect. The δ13Cleaf value for Cedrus Deodara changes with altitude and mean annual precipitation (MAP). A sensitivity of 2.9 ‰ km-1 and 0.3 ‰ /100 mm was calculated for the altitude range of 1.5 km and precipitation range of 700 mm respectively. Although Pinus wallichiana do not show a correlation between elevation and δ13Cleaf value, a negative correlation between MAP and δ13Cleaf value with an average sensitivity of 0.2 ‰ /100 mm for the precipitation range of 900 mm is obtained. Comparison of results acquired from both gymnosperm and angiosperm species shows that gymnosperms are comparatively more sensitive to the climatic factors than angiosperms growing in a similar environmental setting.

  2. Organic farming and heterogeneous landscapes positively affect different measures of plant diversity

    National Research Council Canada - National Science Library

    Rader, Romina; Birkhofer, Klaus; Schmucki, Reto; Smith, Henrik G; Stjernman, Martin; Lindborg, Regina; McKenzie, Ailsa

    2014-01-01

    ...) and farm management intensity (organic vs. conventional farming). Plant species richness and functional diversity metrics all responded positively to landscape heterogeneity, with the strongest effect occurring on conventional...

  3. Plant diversity in hedgerows amidst Atlantic Forest fragments

    Directory of Open Access Journals (Sweden)

    Carolina C. C. Oliveira

    2015-06-01

    Full Text Available Hedgerows are linear structures found in agricultural landscapes that may facilitate dispersal of plants and animals and also serve as habitat. The aim of this study was to investigate the relationships among diversity and ecological traits of woody plants, hedgerow characteristics (size, age, and origin, and the structure of the surrounding Atlantic Forest landscape. Field data were collected from 14 hedgerows, and landscape metrics from 1000-m buffers surrounding hedgerows were recorded from a thematic map. In all sampled hedgerows, arboreal species were predominantly zoochoric and early-succession species, and hedgerow width was an important factor explaining the richness and abundance of this group of species. Connection with forest vegetation did not explain richness and abundance of animal-dispersed species, but richness of non-zoochoric species increased in more connected hedgerows. These results suggest that hedgerows are probably colonized by species arriving from nearby early-succession sites, forest fragment edges, and isolated trees in the matrix. Nonetheless, hedgerows provide resources for frugivorous animals and influence landscape connectivity, highlighting the importance of these elements in the conservation of biodiversity in fragmented and rural landscapes.

  4. Diversity assessment of benthic macroinvertebrates, yeasts, and microbiological indicators along a longitudinal gradient in Serra do Cipó, Brazil

    Directory of Open Access Journals (Sweden)

    M. Callisto

    Full Text Available The main goals of this study were: 1 to evaluate the structure, diversity, and functional trophic group composition of benthic macroinvertebrate communities; 2 to characterize water quality in the headwaters of the Doce river watershed, based on physical, chemical, and biological parameters (benthic macroinvertebrates, fecal coliforms, heterotrophic bacteria, and yeasts; and 3 to contribute to the knowledge of the structure and function of longitudinal gradients in lotic ecosystems in Brazil. A total of 60 benthic macroinvertebrate taxa were identified, the dominant group being the aquatic insects, with 50 families distributed in 8 orders. The dry period presented higher values of taxonomic richness and total density of benthic macroinvertebrates. A decreasing gradient was observed in these variable values from the 3rd order stretch down to the 6th order stretch. The highest Shannon-Wiener diversity values were found in the rainy period in the 3rd order stretches, which presented well-developed riparian forest. Besides the 3rd order stretches, the Pielou evenness index values were also high in the 6th order stretch. The collectors, together with the scrapers, predominated in the benthic macroinvertebrate communities in all river stretches, except in the 2nd, 4th, and 5th order stretches in the rainy period, where communities were dominated by filterers. The shredders and predators presented low densities for all river stretches. All microbiological variables presented low levels. Due to the high counts of heterotrophic bacteria and coliforms, the studied river stretches presented inadequate potability but adequate balneability levels. The results suggest that the structure, diversity, and composition of the benthic macroinvertebrate communities are influenced by the trophic resource availability, seasonality, and sediment heterogeneity. The microbiological results of this study allow inferring that the waters from Serra do Cipó have excellent

  5. Exploring the origin of the latitudinal diversity gradient: Contrasting the sister fern genera Phegopteris and Pseudophegopteris

    Institute of Scientific and Technical Information of China (English)

    Harald SCHNEIDER; Li-Juan HE; Jeannine MARQUARDT; Li WANG; Jochen HEINRICHS; Sabine HENNEQUIN; Xian-Chun ZHANG

    2013-01-01

    The origin of the latitudinal biodiversity gradient has been studied using various approaches.Here,we employ a comparative phylogenetic approach to infer evidence for the hypothesis that differences in diversification rates are one of the main factors contributing to the assembly of this gradient.We infer the phylogeny of the two sister genera Phegopteris and Pseudophegopteris.The two genera are distinct in their species richness (4 vs.20 spp.) and their preferences to temperate to subtropical (Phegopteris) or tropical climates (Pseudophegopteris).Using sequences of three plastid DNA regions,we confirm the monophyly of each genus and infer the inter-and intra-generic phylogenetic differentiation of the sister clades.We recover evidence for distinct net-diversification rate between the two genera,which may be caused either by a higher extinction risk of temperate Phegopteris or a higher speciation rate of tropical Pseudophegopteris.We discuss our results in the context of our current knowledge on the speciation processes of ferns.We conclude on the crucial influence of other factors such as the rise of the Himalaya on the diversification of these fems.

  6. Vascular plant removal effects on biological N fixation vary across a boreal forest island gradient.

    Science.gov (United States)

    Gundale, Michael J; Wardle, David A; Nilsson, Marie-Charlotte

    2010-06-01

    There is currently much interest in understanding how biodiversity loss affects the functioning of ecosystems, but few studies have evaluated how ecosystem processes change in response to one another following biodiversity loss. We focused on a well-described gradient of 30 forested lake islands in northern Sweden, where island size determines the occurrence of lightning-ignited wildfire, which in turn determines successional stage, plant species composition, and productivity. We investigated the effect of biodiversity loss on biological nitrogen fixation by feathermosses through an experiment consisting of factorial removals of three understory shrub species (Vaccinium myrtillis, Vaccinium vitis-idaea, and Empetrum hermaphroditum) and two plant functional groups (shrubs and tree roots). We tested the hypothesis that, following vascular plant species loss, N fixation rates would be impaired by changes in pools or processes that increase extractable soil N, because changes in the supply rate of N to feathermosses should influence their demand for newly fixed N. Further, we hypothesized that the effects of removals on N fixation would depend on environmental context (i.e., island size), because it has been previously demonstrated that the effect of vascular plant species removal on N recycling pools and processes was strongest on productive islands. The data demonstrated that removal of two shrub species (V. vitis-idaea and E. hermaphroditum) negatively aflected the N fixation of Hylocomium splendens, but positively affected Pleurozium schreberi, resulting in unchanged areal N fixation rates. In the functional removal experiment, tree root removal resulted in a significant negative effect on N fixation. The effects of shrub and root removals on N fixation occurred only on small islands and thus were context dependent. This pattern did not correspond to the effect of shrub and root removal treatments on N-recycling pools or processes, which only occurred in response

  7. Symbiodinium (Dinophyceae) diversity in reef-invertebrates along an offshore to inshore reef gradient near Lizard Island, Great Barrier Reef.

    Science.gov (United States)

    Tonk, Linda; Sampayo, Eugenia M; LaJeunesse, Todd C; Schrameyer, Verena; Hoegh-Guldberg, Ove

    2014-06-01

    Despite extensive work on the genetic diversity of reef invertebrate-dinoflagellate symbioses on the Great Barrier Reef (GBR; Australia), large information gaps exist from northern and inshore regions. Therefore, a broad survey was done comparing the community of inshore, mid-shelf and outer reefs at the latitude of Lizard Island. Symbiodinium (Freudenthal) diversity was characterized using denaturing gradient gel electrophoresis fingerprinting and sequencing of the ITS2 region of the ribosomal DNA. Thirty-nine distinct Symbiodinium types were identified from four subgeneric clades (B, C, D, and G). Several Symbiodinium types originally characterized from the Indian Ocean were discovered as well as eight novel types (C1kk, C1LL, C3nn, C26b, C161a, C162, C165, C166). Multivariate analyses on the Symbiodinium species diversity data showed a strong link with host identity, consistent with previous findings. Of the four environmental variables tested, mean austral winter sea surface temperature (SST) influenced Symbiodinium distribution across shelves most significantly. A similar result was found when the analysis was performed on Symbiodinium diversity data of genera with an open symbiont transmission mode separately with chl a and PAR explaining additional variation. This study underscores the importance of SST and water quality related variables as factors driving Symbiodinium distribution on cross-shelf scales. Furthermore, this study expands our knowledge on Symbiodinium species diversity, ecological partitioning (including host-specificity) and geographic ranges across the GBR. The accelerating rate of environmental change experienced by coral reef ecosystems emphasizes the need to comprehend the full complexity of cnidarian symbioses, including the biotic and abiotic factors that shape their current distributions.

  8. Advancing biodiversity-ecosystem functioning science using high-density tree-based experiments over functional diversity gradients.

    Science.gov (United States)

    Tobner, Cornelia M; Paquette, Alain; Reich, Peter B; Gravel, Dominique; Messier, Christian

    2014-03-01

    Increasing concern about loss of biodiversity and its effects on ecosystem functioning has triggered a series of manipulative experiments worldwide, which have demonstrated a general trend for ecosystem functioning to increase with diversity. General mechanisms proposed to explain diversity effects include complementary resource use and invoke a key role for species' functional traits. The actual mechanisms by which complementary resource use occurs remain, however, poorly understood, as well as whether they apply to tree-dominated ecosystems. Here we present an experimental approach offering multiple innovative aspects to the field of biodiversity-ecosystem functioning (BEF) research. The International Diversity Experiment Network with Trees (IDENT) allows research to be conducted at several hierarchical levels within individuals, neighborhoods, and communities. The network investigates questions related to intraspecific trait variation, complementarity, and environmental stress. The goal of IDENT is to identify some of the mechanisms through which individuals and species interact to promote coexistence and the complementary use of resources. IDENT includes several implemented and planned sites in North America and Europe, and uses a replicated design of high-density tree plots of fixed species-richness levels varying in functional diversity (FD). The design reduces the space and time needed for trees to interact allowing a thorough set of mixtures varying over different diversity gradients (specific, functional, phylogenetic) and environmental conditions (e.g., water stress) to be tested in the field. The intention of this paper is to share the experience in designing FD-focused BEF experiments with trees, to favor collaborations and expand the network to different conditions.

  9. Herpetological diversity along Andean elevational gradients: links with physiological ecology and evolutionary physiology.

    Science.gov (United States)

    Navas, Carlos A

    2002-11-01

    A well-defined macroecological pattern is the decline in biodiversity with altitude. However, this decline is taxa-specific. For example, amphibians are more diverse than squamates at extreme elevations in the tropical Andes, but this pattern is reversed at extreme elevations in the southern latitudes. Several ecophysiological and evolutionary factors may be related to this difference. At high-elevations in southern latitudes temperature differs dramatically among seasons and dry soils dominate, characteristics that appear to favor lizard physiological ecology. Tropical high altitudes, in contrast, are humid and offer abundant and diverse water resources. These characteristics allow for a richer anuran community but might complicate lizard egg development through temperature and oxygen constrains. Differences in strategies of thermal adaptation might also modulate diversity patterns. The thermal physiology of anurans is extremely labile so that behavioral and physiological performance is maintained despite an altitudinal decrease in field body temperature. Lizards, in contrast, exhibit a conservative thermal physiology and rely on behavioral thermoregulation to face cold and variable temperatures. Both, lizard behavioral strategies and anuran physiological adjustments seem equally efficient in allowing ecological success and diversification for both groups in the tropics up to approximately 3000 m. At higher elevations physiological thermal adaptation is required, and lizards are ecologically constrained, perhaps at various ontogenetic stages. Patterns of biodiversity along environmental clines can be better understood through a physiological approach, and can help to refine and propose hypotheses in evolutionary physiology.

  10. Altitudinal gradients of bryophyte diversity and community assemblage in southern Appalachian spruce-fir forests

    Science.gov (United States)

    Sarah E. Stehn; Christopher R. Webster; Janice M. Glime; Michael A. Jenkins

    2010-01-01

    Ground-layer plant communities in spruce-fir forests of the southern Appalachians have likely undergone significant change since the widespread death of canopy Fraser fir (Abies fraseri) caused by the exotic balsam woolly adelgid (Adelges piceae). Bryophytes comprise an important part of the ground-layer flora in the spruce-fir...

  11. Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt

    Directory of Open Access Journals (Sweden)

    Amira L. Hanna

    2013-01-01

    Full Text Available North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp. and 30 annuals (e.g. Bromus spp., Erodium spp.. Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs; the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere and shoot (endophyllosphere tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium, Bacillus pumilus, Bacillus polymexa, Bacillus macerans, Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans, Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera, Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola. Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the

  12. Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt.

    Science.gov (United States)

    Hanna, Amira L; Youssef, Hanan H; Amer, Wafaa M; Monib, Mohammed; Fayez, Mohammed; Hegazi, Nabil A

    2013-01-01

    North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium, Bacillus pumilus, Bacillus polymexa, Bacillus macerans, Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans, Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera, Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola. Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El

  13. Decreases in ammonia volatilization in response to greater plant diversity in microcosms of constructed wetlands

    Science.gov (United States)

    Luo, Bin; Ge, Ying; Han, Wenjuan; Fan, Xing; Ren, Yuan; Du, Yuanyuan; Shi, Mengmeng; Chang, Jie

    2016-10-01

    Ammonia volatilization from wastewaters with a high concentration of ammonium is a serious environmental and health problem. Constructed wetlands (CWs) are widely used for treating wastewater, and plant diversity clearly improves some functions of ecosystem such as nitrogen removal. However, whether plant diversity can affect ammonia volatilization from wastewater is still unknown. In this study, we conducted a microcosm experiment with different plant diversity treatments using four plant species. Results showed that, (1) ammonia volatilization decreased with increasing plant species richness; (2) ammonia volatilization from systems containing Rumex japonicus was lower than other systems; and (3) ammonia volatilization was affected more by species composition than species richness. This paper is the first to report that ammonia volatilization is reduced by plant diversity, and that some plant species combinations are important to reduce ammonia volatilization from CWs when treating wastewater.

  14. Invasive plant erodes local song diversity in a migratory passerine.

    Science.gov (United States)

    Ortega, Yvette K; Benson, Aubree; Greene, Erick

    2014-02-01

    Exotic plant invasions threaten ecosystems globally, but we still know little about the specific consequences for animals. Invasive plants can alter the quality of breeding habitat for songbirds, thereby impacting important demographic traits such as dispersal, philopatry, and age structure. These demographic effects may in turn alter song-learning conditions to affect song structure and diversity. We studied Chipping Sparrows (Spizella passerina) breeding in six savannas that were either dominated by native vegetation or invaded by spotted knapweed (Centaurea stoebe), an exotic forb known to diminish food resources and reproductive success. Here, we report that the prevalence of older birds was relatively low in knapweed-invaded habitat, where recruitment of yearlings compensated for diminished site fidelity to sustain territory abundance. In both habitat types, yearling males tended to adopt songs similar to their neighbors and match the songs of older birds rather than introducing new song types, a pattern seen in many songbird species. As a consequence, in invaded habitat where age structure was skewed away from older birds serving as potential song models, yearlings converged on fewer song types. Similarity of songs among individuals was significantly higher and the overall number of song types averaged nearly 20% lower in invaded relative to native habitat. Degradation of habitat quality generally impacts site fidelity and age ratios in migratory songbirds and hence may commonly alter song-learning conditions. Associated shifts in song attributes known to influence reproductive success could in turn enforce demographic declines driven by habitat degradation. Local song structure may serve as an important indicator of habitat quality and population status for songbirds.

  15. Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis

    NARCIS (Netherlands)

    Bobbink, R.; Hicks, K.; Galloway, J.; Spranger, T.; Alkemade, R.; Ashmore, M.R.; Bustamante, M.; Cinderby, S.; Davidson, E.; Dentener, F.; Emmett, B.; Erisman, J.W.; Fenn, M.; Gilliam, F.; Nordin, A.; Pardo, L.; Vries, de W.

    2010-01-01

    Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range

  16. Data from: Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Strecker, Tanja; Lanoue, Arnaud; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, L.

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  17. Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Lanoue, Arnaud; Strecker, Tanja; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, Liesje

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  18. Nitrogen deposition reduces plant diversity and alters ecosystem functioning: field-scale evidence from a nationwide survey of UK heathlands.

    Directory of Open Access Journals (Sweden)

    Georgina E Southon

    Full Text Available Findings from nitrogen (N manipulation studies have provided strong evidence of the detrimental impacts of elevated N deposition on the structure and functioning of heathland ecosystems. Few studies, however, have sought to establish whether experimentally observed responses are also apparent under natural, field conditions. This paper presents the findings of a nationwide field-scale evaluation of British heathlands, across broad geographical, climatic and pollution gradients. Fifty two heathlands were selected across an N deposition gradient of 5.9 to 32.4 kg ha(-1 yr(-1. The diversity and abundance of higher and lower plants and a suite of biogeochemical measures were evaluated in relation to climate and N deposition indices. Plant species richness declined with increasing temperature and N deposition, and the abundance of nitrophilous species increased with increasing N. Relationships were broadly similar between upland and lowland sites, with the biggest reductions in species number associated with increasing N inputs at the low end of the deposition range. Both oxidised and reduced forms of N were associated with species declines, although reduced N appears to be a stronger driver of species loss at the functional group level. Plant and soil biochemical indices were related to temperature, rainfall and N deposition. Litter C:N ratios and enzyme (phenol-oxidase and phosphomonoesterase activities had the strongest relationships with site N inputs and appear to represent reliable field indicators of N deposition. This study provides strong, field-scale evidence of links between N deposition--in both oxidised and reduced forms--and widespread changes in the composition, diversity and functioning of British heathlands. The similarity of relationships between upland and lowland environments, across broad spatial and climatic gradients, highlights the ubiquity of relationships with N, and suggests that N deposition is contributing to biodiversity

  19. The effect of latitudinal gradient on the species diversity of Chinese litter-dwelling thrips

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2014-06-01

    Full Text Available To understand the global distribution patterns of litter-dwelling thrips, a total 150 leaf litter samples were collected from 6 natural reserves located in three climatic regions, temperate, subtropical and tropical. The results showed the relative abundance of Thysanoptera was over 3.0% in 4 natural reserves from subtropical and tropical zone, and reached 5.9% in one tropical reserve, only less than Acarina and Collembola. In contrast it was only 0.3% in the warm temperate natural reserves, and no thrips were collected in a mid temperate reserve. The order on the average species numbers per plot of litter thrips was tropic > subtropics > temperate (n=25, p<0.05. Mean density of litter thrips per plots in the tropics and subtropics was significantly higher than that in the temperate region (n=25, p<0.05, but the average density was not significantly different between tropical and subtropical zones (n=25, p>0.05. The diversity of litter thrips in the tropics and subtropics was much higher than that in the temperate area based on comparsions of Shannon-Wiener diversity index (H΄, Pielou eveness index (J, and Simpson dominance index (D. All of these results indicated that litter-dwelling thrips lived mainly in tropical and subtropical regions; meanwhile, species number and relative abundance increased with decreasing latitude.

  20. Plant species diversity of wetland ecosystem in an arid and semi-arid region in northwest China

    Institute of Scientific and Technical Information of China (English)

    LI Rui; LIU Yunfang; ZHANG Kebin

    2007-01-01

    In order to study the changes of plant species diversity along the biotope gradient and its influencing factors in a wetland-add grassland ecosystem in the add and semi-arid regions of northwest China,four transect lines were set along the biotope gradient in four directions:east,northeast,west and northwest,and altogether 123 sample plots were investigated on species composition,density,foliage cover,height and biomass (calculated in fresh weight).The whole study area was divided into the Wetland zone,the ecotone and the arid grassland zone in terms of habitat characteristics and vegetation types.In this paper,we analyzed and compared the species diversity in the ecotone of a wetland-dry grassland ecosystem in Yanchi County,Ningxia Hui Autonomous Region,with the help of biodiversity software BioDiversity Pro and statistical software Microcal Origin,as well as the combined measurement of species diversity indices.The results revealed distinct differences between those three vegetation zones along each transect line.The ecotone had the highest richness indices (R) and comprehensive diversity indices (Y),reflecting the edge effect.The greatest evenness indices (E) were found in the add grassland zones.This result agreed with the phenomenon of desertification reversion,vegetation restoration and dominant communities' formation.As for the four transect lines,the east and the northeast scored higher in each diversity index than the others due to less human disturbance,gentler topography uplift and more intercepted materials and energies.The highest Simpson index value was found in the northeast transect line,which was 39.9% higher than the lowest in the Northwest.

  1. 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.

  2. Using a multi-trait approach to manipulate plant functional diversity in a biodiversity-ecosystem function experiment.

    Directory of Open Access Journals (Sweden)

    Conrad Schittko

    Full Text Available A frequent pattern emerging from biodiversity-ecosystem function studies is that functional group richness enhances ecosystem functions such as primary productivity. However, the manipulation of functional group richness goes along with major disadvantages like the transformation of functional trait data into categories or the exclusion of functional differences between organisms in the same group. In a mesocosm study we manipulated plant functional diversity based on the multi-trait Functional Diversity (FD-approach of Petchey and Gaston by using database data of seven functional traits and information on the origin of the species in terms of being native or exotic. Along a gradient ranging from low to high FD we planted 40 randomly selected eight-species mixtures under controlled conditions. We found a significant positive linear correlation of FD with aboveground productivity and a negative correlation with invasibility of the plant communities. Based on community-weighted mean calculations for each functional trait, we figured out that the traits N-fixation and species origin, i.e. being native or exotic, played the most important role for community productivity. Our results suggest that the identification of the impact of functional trait diversity and the relative contributions of relevant traits is essential for a mechanistic understanding of the role of biodiversity for ecosystem functions such as aboveground biomass production and resistance against invasion.

  3. Using a multi-trait approach to manipulate plant functional diversity in a biodiversity-ecosystem function experiment.

    Science.gov (United States)

    Schittko, Conrad; Hawa, Mahmoud; Wurst, Susanne

    2014-01-01

    A frequent pattern emerging from biodiversity-ecosystem function studies is that functional group richness enhances ecosystem functions such as primary productivity. However, the manipulation of functional group richness goes along with major disadvantages like the transformation of functional trait data into categories or the exclusion of functional differences between organisms in the same group. In a mesocosm study we manipulated plant functional diversity based on the multi-trait Functional Diversity (FD)-approach of Petchey and Gaston by using database data of seven functional traits and information on the origin of the species in terms of being native or exotic. Along a gradient ranging from low to high FD we planted 40 randomly selected eight-species mixtures under controlled conditions. We found a significant positive linear correlation of FD with aboveground productivity and a negative correlation with invasibility of the plant communities. Based on community-weighted mean calculations for each functional trait, we figured out that the traits N-fixation and species origin, i.e. being native or exotic, played the most important role for community productivity. Our results suggest that the identification of the impact of functional trait diversity and the relative contributions of relevant traits is essential for a mechanistic understanding of the role of biodiversity for ecosystem functions such as aboveground biomass production and resistance against invasion.

  4. Some effects of high- gradient magnetic field on tropism of roots of higher plants

    Science.gov (United States)

    Kondrachuk, A.; Belyavskaya, N.

    The perception of gravity in living organisms is mostly based on the response of the gravisensing system to displacement of some specific mass caused by gravitational force. According to the starch-statolith hypothesis the amyloplasts play the role of specific mass in gravisensing cells of higher plants. Kuznetsov & Hasenstein (1996) have demonstrated that the high-gradient magnetic field (HGMF) exerts a directional ponderomotive force on diamagnetic substances, in particular, statoliths. This effect of the HGMF causes root response similar to that produced by the change in gravity vector. Their studies supported the starch-statolith hypothesis and showed that ponderomotive force can be used to modify force acting on statoliths by manipulating statolith locations within gravisensing cells. We have designed the HGMF facility that allows for generating the HGMF and analyzing its effects on higher plants' roots. It records by videosystem and measures with the help of image analysis software the parameters of kinetics of root bending under both the HGMF action and gravistimulation. Two species of plants (pea and cress) have been examined. The main results of the work are the following: 1) The magnetotropic effect of HGMF on root growth was found for both species. 2) The critical value of ponderomotive force that caused the magnetotropic effect was estimated by modeling the magnetic field spatial distribution in the region of root apex. 3) The electron-microscopic analysis of statocytes after the HGMF treatment was carried out. The displacement of amyloplasts in root statocytes of two species of plants in HGMF was firstly demonstrated at the ultrastructural level. 4) Spatial distribution of exogenous proton fluxes (pH) along the roots was studied. The changes in pH distribution along curvature zone and apices of roots were revealed in the HGMF. It is known that application of HGMFs or strong uniform magnetic fields may influence ion transport due to Ampere force. It

  5. Riparian plant composition along hydrologic gradients in a dryland river basin and implications for a warming climate

    Science.gov (United States)

    Reynolds, Lindsay; Shafroth, Patrick B.

    2017-01-01

    Droughts in dryland regions on all continents are expected to increase in severity and duration under future climate projections. In dryland regions, it is likely that minimum streamflow will decrease with some perennial streams shifting to intermittent flow under climate-driven changes in precipitation and runoff and increases in temperature. Decreasing base flow and shifting flow regimes from perennial to intermittent could have significant implications for stream-dependent biota, including riparian vegetation. In this study, we asked, how do riparian plant communities vary along wet-to-dry hydrologic gradients on small (first–third order) streams? We collected data on geomorphic, hydrologic, and plant community characteristics on 54 stream sites ranging in hydrology from intermittent to perennial flow across the Upper Colorado River Basin (284,898 km2). We found that plant communities varied along hydrologic gradients from high to low elevation between streams, and perennial to intermittent flow. We identified indicator species associated with different hydrologic conditions and suggest how plant communities may shift under warmer, drier conditions. Our results indicate that species richness and cover of total, perennial, wetland, and native plant groups will decrease while annual plants will increase under drying conditions. Understanding how plant communities respond to regional drivers such as hydroclimate requires broad-scale approaches such as sampling across whole river basins. With increasingly arid conditions in many regions of the globe, understanding plant community shifts is key to understanding the future of riparian ecosystems.

  6. Small scale spatial gradients of outdoor and indoor benzene in proximity of an integrated steel plant.

    Science.gov (United States)

    Licen, Sabina; Tolloi, Arianna; Briguglio, Sara; Piazzalunga, Andrea; Adami, Gianpiero; Barbieri, Pierluigi

    2016-05-15

    Benzene is known as a human carcinogen, whose annual mean concentration exceeded the EU limit value (5 μg/m(3)) only in very few locations in Europe during 2012. Nevertheless 10% to 12% of the EU-28 urban population was still exposed to benzene concentrations above the WHO reference level of 1.7 μg/m(3). WHO recommended a wise choice of monitoring stations positioning in proximity of "hot spots" to define and assess the representativeness of each site paying attention to micro-scale conditions. In this context benzene and other VOCs of health concern (toluene, ethylbenzene, xylenes) concentrations have been investigated, with weekly passive sampling for one year, both in outdoor and indoor air in inhabited buildings in close proximity (180 m far up to 1100 m) of an integrated steel plant in NE of Italy. Even though the outdoor mean annual benzene concentration was below the EU limit in every site, in the site closest to the works the benzene concentration was above 5 μg/m(3) in 14 weeks. These events were related to a benzene over toluene ratio above one, which is diagnostic for the presence of an industrial source, and to meteorological factors. These information pointed at the identification of the coke ovens of the plant as the dominant outdoor source of benzene. Benzene gradients with the increasing distance from coke ovens have been found for both outdoor and indoor air. Linear models linking outdoor to indoor benzene concentrations have been then identified, allowing to estimate indoor exposure from ambient air benzene data. In the considered period, a narrow area of about 250 m appeared impacted at a higher degree than the other sites both considering outdoor and indoor air. Passive BTEX sampling permits to collect information on both ambient air and daily life settings, allowing to assemble a valuable data support for further environmental cost-benefit analyses. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Phytochemical diversity of the essential oils of Mexican Oregano (Lippia graveolens Kunth) populations along an Edapho-climatic gradient.

    Science.gov (United States)

    Calvo-Irabién, Luz María; Parra-Tabla, Victor; Acosta-Arriola, Violeta; Escalante-Erosa, Fabiola; Díaz-Vera, Luciana; Dzib, Gabriel R; Peña-Rodríguez, Luis Manuel

    2014-07-01

    Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non-cultivated populations. Mexican oregano essential oil showed important variation in the essential-oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC-FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89-99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non-phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi-arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High-oil-yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs.

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

    Science.gov (United States)

    Meier, Courtney L; Bowman, William D

    2008-12-16

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

  9. Analysis of microbial diversity on deli slicers using polymerase chain reaction and denaturing gradient gel electrophoresis technologies.

    Science.gov (United States)

    Koo, O K; Mertz, A W; Akins, E L; Sirsat, S A; Neal, J A; Morawicki, R; Crandall, P G; Ricke, S C

    2013-02-01

    Cross-contamination of pathogenic and spoilage bacteria from food-contact surfaces to food products is a serious public health issue. Bacteria may survive and attach to food-contact surfaces by residual food components and/or background bacteria which may subsequently transfer to other food products. Deli slicers, generally used for slicing ready-to-eat products, can serve as potential sources for considerable bacterial transfer. The objective of this study was to assess the extent and distribution of microbial diversity of deli slicers by identification of pathogenic and background bacteria. Slicer-swab samples were collected from restaurants in Arkansas and Texas in the United States. Ten surface areas for each slicer were swabbed using sterile sponges. Denaturing gradient gel electrophoresis (DGGE) was applied to investigate the fingerprint of samples, and each band was further identified by sequence analysis. Pseudomonads were identified as the dominant bacteria followed by Enterobacteriaceae family, and lactic acid bacteria such as Lactococcus lactis and Streptococcus thermophilus were also found. Bacterial distribution was similar for all surface areas, while the blade guard exhibited the greatest diversity. This study provides a profile of the microbial ecology of slicers using DGGE to develop more specific sanitation practices and to reduce cross-contamination during slicing.

  10. Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity.

    Science.gov (United States)

    Stein, Claudia; Rissmann, Cornelia; Hempel, Stefan; Renker, Carsten; Buscot, François; Prati, Daniel; Auge, Harald

    2009-02-01

    Plant communities can be affected both by arbuscular mycorrhizal fungi (AMF) and hemiparasitic plants. However, little is known about the interactive effects of these two biotic factors on the productivity and diversity of plant communities. To address this question, we set up a greenhouse study in which different AMF inocula and a hemiparasitic plant (Rhinanthus minor) were added to experimental grassland communities in a fully factorial design. In addition, single plants of each species in the grassland community were grown with the same treatments to distinguish direct AMF effects from indirect effects via plant competition. We found that AMF changed plant community structure by influencing the plant species differently. At the community level, AMF decreased the productivity by 15-24%, depending on the particular AMF treatment, mainly because two dominant species, Holcus lanatus and Plantago lanceolata, showed a negative mycorrhizal dependency. Concomitantly, plant diversity increased due to AMF inoculation and was highest in the treatment with a combination of two commercial AM strains. AMF had a positive effect on growth of the hemiparasite, and thereby induced a negative impact of the hemiparasite on host plant biomass which was not found in non-inoculated communities. However, the hemiparasite did not increase plant diversity. Our results highlight the importance of interactions with soil microbes for plant community structure and that these indirect effects can vary among AMF treatments. We conclude that mutualistic interactions with AMF, but not antagonistic interactions with a root hemiparasite, promote plant diversity in this grassland community.

  11. Influence of plant genetic diversity on interactions between higher trophic levels.

    Science.gov (United States)

    Moreira, Xoaquín; Mooney, Kailen A

    2013-06-23

    While the ecological consequences of plant diversity have received much attention, the mechanisms by which intraspecific diversity affects associated communities remains understudied. We report on a field experiment documenting the effects of patch diversity in the plant Baccharis salicifolia (genotypic monocultures versus polycultures of four genotypes), ants (presence versus absence) and their interaction on ant-tended aphids, ants and parasitic wasps, and the mechanistic pathways by which diversity influences their multi-trophic interactions. Five months after planting, polycultures (versus monocultures) had increased abundances of aphids (threefold), ants (3.2-fold) and parasitoids (1.7-fold) owing to non-additive effects of genetic diversity. The effect on aphids was direct, as plant genetic diversity did not mediate ant-aphid, parasitoid-aphid or ant-parasitoid interactions. This increase in aphid abundance occurred even though plant growth (and thus aphid resources) was not higher in polycultures. The increase in ants and parasitoids was an indirect effect, due entirely to higher aphid abundance. Ants reduced parasitoid abundance by 60 per cent, but did not affect aphid abundance or plant growth, and these top-down effects were equivalent between monocultures and polycultures. In summary, intraspecific plant diversity did not increase primary productivity, but nevertheless had strong effects across multiple trophic levels, and effects on both herbivore mutualists and enemies could be predicted entirely as an extension of plant-herbivore interactions.

  12. Diversity of meiofauna from the 9°50'N East Pacific rise across a gradient of hydrothermal fluid emissions.

    Directory of Open Access Journals (Sweden)

    Sabine Gollner

    Full Text Available We studied the meiofauna community at deep-sea hydrothermal vents along a gradient of vent fluid emissions in the axial summit trought (AST of the East Pacific Rise 9°50'N region. The gradient ranged from extreme high temperatures, high sulfide concentrations, and low pH at sulfide chimneys to ambient deep-sea water conditions on bare basalt. We explore meiofauna diversity and abundance, and discuss its possible underlying ecological and evolutionary processes.After sampling in five physico-chemically different habitats, the meiofauna was sorted, counted and classified. Abundances were low at all sites. A total of 52 species were identified at vent habitats. The vent community was dominated by hard substrate generalists that also lived on bare basalt at ambient deep-sea temperature in the axial summit trough (AST generalists. Some vent species were restricted to a specific vent habitat (vent specialists, but others occurred over a wide range of physico-chemical conditions (vent generalists. Additionally, 35 species were only found on cold bare basalt (basalt specialists. At vent sites, species richness and diversity clearly increased with decreasing influence of vent fluid emissions from extreme flow sulfide chimney (no fauna, high flow pompei worm (S: 4-7, H'(loge: 0.11-0.45, vigorous flow tubeworm (S: 8-23; H'(loge: 0.44-2.00 to low flow mussel habitats (S: 28-31; H'(loge: 2.34-2.60.Our data suggest that with increasing temperature and toxic hydrogen sulfide concentrations and increasing amplitude of variation of these factors, fewer species are able to cope with these extreme conditions. This results in less diverse communities in more extreme habitats. The finding of many species being present at sites with and without vent fluid emissions points to a non endemic deep-sea hydrothermal vent meiofaunal community. This is in contrast to a mostly endemic macrofauna but similar to what is known for meiofauna from shallow-water vents.

  13. Fossil wood diversity gradient and Far-East Asia palaeoclimatology during the Late Triassic - Cretaceous interval

    Science.gov (United States)

    Oh, Changhwan; Legrand, Julien; Kim, Kyungsik; Philippe, Marc; SungPaik, In

    2011-02-01

    Mesozoic fossil floras are distributed over eastern Asia (China, Mongolia, Siberia, Korea and Japan) according to a regular latitudinal pattern. Two floras are usually distinguished, a northern type and a southern type, the distribution of which oscillated during the Mesozoic. In Japan, this regular pattern is disrupted by a sharp inflexion of the boundary between the two floras. Two competing hypotheses have been proposed to explain this disruption. One hypothesis advocates later tectonic motion clouding the original pattern, while the other hypothesis proposes that a warm oceanic current allowed the southern flora to grow much further north in coastal areas. We used fossil wood, a biotic component that has not previously been used, for a palaeobiogeographical study of the region. The observed fossil wood diversity at the generic level does not fit with the hypothesis of a warm oceanic current, unless this hypothesis is modified to include alternating warm northbound and cold southbound oceanic currents. Our results provide new evidence for the palaeoecology of the Mesozoic continental biota in Far-East Asia.

  14. Genetic diversity in Scots pine populations along a radiation exposure gradient

    Energy Technology Data Exchange (ETDEWEB)

    Geras' kin, Stanislav A., E-mail: stgeraskin@gmail.com; Volkova, Polina Yu.

    2014-10-15

    Polymorphisms of antioxidant enzymes were studied in the endosperm and embryos of seeds from Scots pine populations inhabiting sites in the Bryansk region of Russia radioactively contaminated as a result of the Chernobyl accident. Chronic radiation exposure at dose rates from 0.8 μGy/h led to a significant increase in the rate of enzymatic loci mutations. The main parameters of genetic variability of the affected Scots pine populations had considerably higher values than those from the reference site. Changes in the genetic makeup of Scots pine populations were observed at dose rates greater than 10.4 μGy/h. However, the higher mutation rate had no effect on the activities of antioxidant enzymes. - Highlights: • Polymorphism of antioxidant enzymes was studied in affected Scots pine populations. • Genetic processes in affected Scots pine populations increase genetic diversity. • Chronic exposure at dose rates from 0.8 μGy/h lead to increasing of mutation rates. • Changes in population genetic structure were observed at dose rates from 10.4 μGy/h. • The higher rate of mutations had no effect on antioxidant enzymes activities.

  15. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Science.gov (United States)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-07-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 %) was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  16. Plant species richness drives the density and diversity of Collembola in temperate grassland

    Science.gov (United States)

    Sabais, Alexander C. W.; Scheu, Stefan; Eisenhauer, Nico

    2011-05-01

    Declining biodiversity is one of the most important aspects of anthropogenic global change phenomena, but the implications of plant species loss for soil decomposers are little understood. We used the experimental grassland community of the Jena Experiment to assess the response of density and diversity of Collembola to varying plant species richness, plant functional group richness and plant functional group identity. We sampled the experimental plots in spring and autumn four years after establishment of the experimental plant communities. Collembola density and diversity significantly increased with plant species and plant functional group richness highlighting the importance of the singular hypothesis for soil invertebrates. Generally, grasses and legumes beneficially affected Collembola density and diversity, whereas effects of small herbs usually were detrimental. These impacts were largely consistent in spring and autumn. By contrast, in the presence of small herbs the density of hemiedaphic Collembola and the diversity of Isotomidae increased in spring whereas they decreased in autumn. Beneficial impacts of plant diversity as well as those of grasses and legumes were likely due to increased root and microbial biomass, and elevated quantity and quality of plant residues serving as food resources for Collembola. By contrast, beneficial impacts of small herbs in spring probably reflect differences in microclimatic conditions, and detrimental effects in autumn likely were due to low quantity and quality of resources. The results point to an intimate relationship between plants and the diversity of belowground biota, even at small spatial scales, contrasting the findings of previous studies. The pronounced response of soil animals in the present study was presumably due to the fact that plant communities had established over several years. As decomposer invertebrates significantly impact plant performance, changes in soil biota density and diversity are likely

  17. Latitudinal species diversity gradient of mushroom corals off eastern Australia: a baseline from the 1970s

    Science.gov (United States)

    Hoeksema, Bert W.

    2015-11-01

    Based on a study of mushroom coral species of eastern Australia, a decrease in species richness can be discerned from north to south. Eastern Australia, including the Great Barrier Reef (GBR), is one of only few coral reef areas suitable for studies on large-scale latitudinal biodiversity patterns. Such patterns may help to recognize biogeographic boundaries and factors regulating biodiversity. Owing to the eastern Australian long coastline, such studies are a logistic challenge unless reliable distribution data are already available, as in museum collections. A large coral collection predominantly sampled from this area in the 1970s is present in the Museum of Tropical Queensland (MTQ). The scleractinian family Fungiidae (mushroom corals), representing about 10% of Indo-Pacific reef coral species, was selected as proxy. It was represented by 1289 specimens belonging to 34 species with latitudinal ranges between 09°09‧S and 31°28‧S. The fauna of the northernmost reefs in the Gulf of Papua and the Torres Strait, and north of the Great Barrier Reef Marine Park (GBRMP), was represented by a maximum of 30 fungiids. From here a southward decline in species number was observed, down to Lord Howe Island with only one species. Together with previous records, the mushroom coral fauna of eastern Australia consists of 37 species, which is more diverse than hitherto known and similar to numbers found in the Coral Triangle. Future field surveys in the GBR should specifically target rarely known species, which are mainly small and found at depths >25 m. In the light of global climate change, they may also show whether previously recorded species are still present and whether their latitudinal ranges have shifted, using the 1970s records as a baseline.

  18. Habitats as complex odour environments: how does plant diversity affect herbivore and parasitoid orientation?

    Directory of Open Access Journals (Sweden)

    Nicole Wäschke

    Full Text Available Plant diversity is known to affect success of host location by pest insects, but its effect on olfactory orientation of non-pest insect species has hardly been addressed. First, we tested in laboratory experiments the hypothesis that non-host plants, which increase odour complexity in habitats, affect the host location ability of herbivores and parasitoids. Furthermore, we recorded field data of plant diversity in addition to herbivore and parasitoid abundance at 77 grassland sites in three different regions in Germany in order to elucidate whether our laboratory results reflect the field situation. As a model system we used the herb Plantago lanceolata, the herbivorous weevil Mecinus pascuorum, and its larval parasitoid Mesopolobus incultus. The laboratory bioassays revealed that both the herbivorous weevil and its larval parasitoid can locate their host plant and host via olfactory cues even in the presence of non-host odour. In a newly established two-circle olfactometer, the weeviĺs capability to detect host plant odour was not affected by odours from non-host plants. However, addition of non-host plant odours to host plant odour enhanced the weeviĺs foraging activity. The parasitoid was attracted by a combination of host plant and host volatiles in both the absence and presence of non-host plant volatiles in a Y-tube olfactometer. In dual choice tests the parasitoid preferred the blend of host plant and host volatiles over its combination with non-host plant volatiles. In the field, no indication was found that high plant diversity disturbs host (plant location by the weevil and its parasitoid. In contrast, plant diversity was positively correlated with weevil abundance, whereas parasitoid abundance was independent of plant diversity. Therefore, we conclude that weevils and parasitoids showed the sensory capacity to successfully cope with complex vegetation odours when searching for hosts.

  19. Plant diversity and conservation in China: planning a strategic bioresource for a sustainable future.

    Science.gov (United States)

    Huang, Hongwen

    2011-01-01

    China is one of the richest countries for plant diversity with approximately 33 000 vascular plant species, ranking second in the world. However, the plant diversity in China is increasingly threatened, with an estimated 4000–5000 plant species being threatened or on the verge of extinction, making China, proportionally, one of the highest priorities for global plant biodiversity conservation. Coming in the face of the current ecological crisis, it is timely that China has launched China's Strategy for Plant Conservation (CSPC). China has increasingly recognized the importance of plant diversity in efforts to conserve and sustainably use its plant diversity. More than 3000 nature reserves have been established, covering approximately 16% of the land surface of China. These natural reserves play important roles in plant conservation, covering more than 85% of types of terrestrial natural ecosystems, 40% of types of natural wetlands, 20% of native forests and 65% of natural communities of vascular plants. Meanwhile, the flora conserved in botanical gardens is also extensive. A recent survey shows that the 10 largest botanical gardens have living collections of 43 502 taxa, with a total of 24 667 species in ex situ conservation. These provide an important reserve of plant resources for sustainable economic and social development in China. Plant diversity is the basis for bioresources and sustainable utilization. The 21st century is predicted to be an era of bio-economy driven by advances of bioscience and biotechnology. Bio-economy may become the fourth economy form after agricultural, industrial, and information and information technology economies, having far-reaching impacts on sustainable development in agriculture, forestry, environmental protection, light industry, food supply and health care and other micro-economy aspects. Thus, a strategic and forward vision for conservation of plant diversity and sustainable use of plant resources in the 21st century is of

  20. Environmental conditions influence the plant functional diversity effect on potential denitrification.

    Directory of Open Access Journals (Sweden)

    Ariana E Sutton-Grier

    Full Text Available Global biodiversity loss has prompted research on the relationship between species diversity and ecosystem functioning. Few studies have examined how plant diversity impacts belowground processes; even fewer have examined how varying resource levels can influence the effect of plant diversity on microbial activity. In a field experiment in a restored wetland, we examined the role of plant trait diversity (or functional diversity, (FD and its interactions with natural levels of variability of soil properties, on a microbial process, denitrification potential (DNP. We demonstrated that FD significantly affected microbial DNP through its interactions with soil conditions; increasing FD led to increased DNP but mainly at higher levels of soil resources. Our results suggest that the effect of species diversity on ecosystem functioning may depend on environmental factors such as resource availability. Future biodiversity experiments should examine how natural levels of environmental variability impact the importance of biodiversity to ecosystem functioning.

  1. Long-term effects of plant diversity and composition on soil nematode communities in model grasslands.

    Science.gov (United States)

    Viketoft, Maria; Bengtsson, Janne; Sohlenius, Björn; Berg, Matty P; Petchey, Owen; Palmborg, Cecilia; Huss-Danell, Kerstin

    2009-01-01

    An important component of plant-soil feedbacks is how plant species identity anddiversity 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 after the establishment of experimental grassland plots at the BIODEPTH site in northern Sweden. This is a substantially longer time than most other experimental studies of plant effects on soil fauna. We address the hypotheses that (la) higher species or functional diversity of plants increases nematode diversity, as well as influences nematode community composition. Alternatively, (1b) individual plant species traits are most important for nematode diversity and community composition. (2) Plant effects on soil organisms will decrease with increasing number of trophic links between plants and soil fauna. Plant species identity was often more important than plant diversity for nematode community composition, supporting hypothesis 1b. There was a weak positive relation between plant and nematode richness;which could be attributed to the presence of the legume Trifolium pratense, but also to some other plant species, suggesting a selection or sampling effect. Several plant species in different functional groups affected nematode community composition. For example, we found that legumes increased bacterial-feeding nematodes, most notably r-selected Rhabditida, while fungal-feeding nematodes were enhanced by forbs. Other bacterial feeders and obligate root feeders were positively related to grasses. Plant effects were usually stronger on plant-, bacterial- and fungal-feeding nematodes than on omnivores/predators, which supports hypothesis 2. Our study suggests that plant identity has stronger effects than plant diversity on nematode community composition, but when comparing our results with similar previous studies the effects of particular plant species appear to vary. We

  2. Plant diversity moderates drought stress in grasslands: Implications from a large real-world study on {sup 13}C natural abundances

    Energy Technology Data Exchange (ETDEWEB)

    Klaus, Valentin H., E-mail: v.klaus@uni-muenster.de [Münster University, Institute for Landscape Ecology, Heisenbergstr. 2, 48149 Münster (Germany); Hölzel, Norbert [Münster University, Institute for Landscape Ecology, Heisenbergstr. 2, 48149 Münster (Germany); Prati, Daniel; Schmitt, Barbara [University of Bern, Institute of Plant Sciences, Altenbergrain 21, 3013 Bern (Switzerland); Schöning, Ingo; Schrumpf, Marion; Solly, Emily F. [Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745 Jena (Germany); Hänsel, Falk [University Marburg, Environmental Informatics, Faculty of Geography, Deutschhausstr. 12, 35037 Marburg (Germany); Fischer, Markus [University of Bern, Institute of Plant Sciences, Altenbergrain 21, 3013 Bern (Switzerland); Kleinebecker, Till [Münster University, Institute for Landscape Ecology, Heisenbergstr. 2, 48149 Münster (Germany)

    2016-10-01

    Land-use change and intensification play a key role in the current biodiversity crisis. The resulting species loss can have severe effects on ecosystem functions and services, thereby increasing ecosystem vulnerability to climate change. We explored whether land-use intensification (i.e. fertilization intensity), plant diversity and other potentially confounding environmental factors may be significantly related to water use (i.e. drought stress) of grassland plants. Drought stress was assessed using δ{sup 13}C abundances in aboveground plant biomass of 150 grassland plots across a gradient of land-use intensity. Under water shortage, plants are forced to increasingly take up the heavier {sup 13}C due to closing stomata leading to an enrichment of {sup 13}C in biomass. Plants were sampled at the community level and for single species, which belong to three different functional groups (one grass, one herb, two legumes). Results show that plant diversity was significantly related to the δ{sup 13}C signal in community, grass and legume biomass indicating that drought stress was lower under higher diversity, although this relation was not significant for the herb species under study. Fertilization, in turn, mostly increased drought stress as indicated by more positive δ{sup 13}C values. This effect was mostly indirect by decreasing plant diversity. In line with these results, we found similar patterns in the δ{sup 13}C signal of the organic matter in the topsoil, indicating a long history of these processes. Our study provided strong indication for a positive biodiversity-ecosystem functioning relationship with reduced drought stress at higher plant diversity. However, it also underlined a negative reinforcing situation: as land-use intensification decreases plant diversity in grasslands, this might subsequently increases drought sensitivity. Vice-versa, enhancing plant diversity in species-poor agricultural grasslands may moderate negative effects of future

  3. Distribution and diversity of carbon monoxide-oxidizing bacteria and bulk bacterial communities across a succession gradient on a Hawaiian volcanic deposit.

    Science.gov (United States)

    Weber, C F; King, G M

    2010-07-01

    Relatively little is known about the distribution and diversity of CO-oxidizing bacteria during succession on volcanic deposits even though they are among the primary colonists. We surveyed CO-oxidizing communities across a vegetation gradient on a 1959 cinder deposit using coxL (large subunit gene of carbon monoxide dehydrogenase) sequences. Sequences most closely related to a coxL sequence from Ktedonobacter racemifer, dominated unvegetated cinders, while Proteobacteria-like sequences dominated vegetated sites. The number of coxL operational taxonomic units (OTUs) increased threefold with increased vegetation, and correlated most strongly with the increased beta-Proteobacteria richness (r = 0.987). These compositional shifts were also reflected in overall bacterial community compositions as determined by 16S rRNA gene analysis. Notably, coxL OTU:16S rRNA OTU ratios increased with increased vegetation, indicating that CO oxidizers became a larger fraction of total bacterial richness during succession. Results from most probable number estimates and maximum potential CO uptake activity assays indicate that increased richness is paralleled by increased CO oxidizer abundance, which likely results from increased vegetation and organic carbon content. Collectively, results suggest that in contrast to patterns observed for plant succession, a versatile bacterial functional group that is important during early colonization and succession can remain important in later stages of succession, irrespective of dramatic environmental changes.

  4. Foliar nitrogen and phosphorus stoichiometry of three wetland plants distributed along an elevation gradient in Dongting Lake, China.

    Science.gov (United States)

    Li, Feng; Gao, Han; Zhu, Lianlian; Xie, Yonghong; Yang, Guishan; Hu, Cong; Chen, Xinsheng; Deng, Zhengmiao

    2017-06-06

    We examined foliar nitrogen (N) and phosphorus (P) stoichiometry of 3 wetland plants (Phalaris arundinacea, Miscanthus sacchariflorus, and Carex brevicuspis) distributed along an elevation gradient in the Dongting Lake, China, and how this stoichiometry is related to soil physico-chemical characteristics, elevation, and flooding days. Plant and soil samples were collected from 3 lakeshore sites. Total N and P concentrations of plants and six physico-chemical characteristics of the soil were measured, in addition to the elevation and flooding days. P. arundinacea and M. sacchariflorus had higher total N and P concentrations than C. brevicuspis. The foliar N:P ratio decreased with increasing elevation, and only increased with increasing foliar total N concentration. Canonical correspondence analysis indicated that the foliar stoichiometry was primarily regulated by soil water content, followed by soil nutrient concentration. The foliar N and P stoichiometry of the 3 wetland plants was insignificantly correlated with soil total P concentration. However, foliar stoichiometric characteristics and soil total N concentration significantly differed among the 3 species. These results demonstrate that spatial variation of foliar stoichiometry in wetland plants exists along an elevation gradient, with this information being useful for the conservation and management of wetland plants in this lake.

  5. Plant functional traits, functional diversity, and ecosystem functioning: current knowledge and perspectives

    Directory of Open Access Journals (Sweden)

    Lingjie Lei

    2016-08-01

    Full Text Available Increasing attention has recently been focused on the linkages between plant functional traits and ecosystem functioning. A comprehensive understanding of these linkages can facilitate to address the ecological consequences of plant species loss induced by human activities and climate change, and provide theoretical support for ecological restoration and ecosystem management. In recent twenty years, the evidence of strong correlations between plant functional traits and changes in ecosystem processes is growing. More importantly, ecosystem functioning can be predicted more precisely, using plant functional trait diversity (i.e., functional diversity than species diversity. In this paper, we first defined plant functional traits and their important roles in determining ecosystem processes. Then, we review recent advances in the relationships between ecosystem functions and plant functional traits and their diversity. Finally, we propose several important future research directions, including (1 exploration of the relationships between aboveground and belowground plant traits and their roles in determining ecosystem functioning, (2 incorporation of the impacts of consumer and global environmental change into the correlation between plant functional traits and ecosystem functioning, (3 effects of functional diversity on ecosystem multifunctionality, and (4 examination of the functional diversity-ecosystem functioning relationship at different temporal and spatial scales.

  6. Diversity Strategies for Nuclear Power Plant Instrumentation and Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Richard Thomas [ORNL; Belles, Randy [ORNL; Cetiner, Mustafa Sacit [ORNL; Holcomb, David Eugene [ORNL; Korsah, Kofi [ORNL; Loebl, Andy [ORNL; Mays, Gary T [ORNL; Muhlheim, Michael David [ORNL; Mullens, James Allen [ORNL; Poore III, Willis P [ORNL; Qualls, A L [ORNL; Wilson, Thomas L [ORNL; Waterman, Michael E. [U.S. Nuclear Regulatory Commission

    2010-02-01

    This report presents the technical basis for establishing acceptable mitigating strategies that resolve diversity and defense-in-depth (D3) assessment findings and conform to U.S. Nuclear Regulatory Commission (NRC) requirements. The research approach employed to establish appropriate diversity strategies involves investigation of available documentation on D3 methods and experience from nuclear power and nonnuclear industries, capture of expert knowledge and lessons learned, determination of best practices, and assessment of the nature of common-cause failures (CCFs) and compensating diversity attributes. The research described in this report does not provide guidance on how to determine the need for diversity in a safety system to mitigate the consequences of potential CCFs. Rather, the scope of this report provides guidance to the staff and nuclear industry after a licensee or applicant has performed a D3 assessment per NUREG/CR-6303 and determined that diversity in a safety system is needed for mitigating the consequences of potential CCFs identified in the evaluation of the safety system design features. Succinctly, the purpose of the research described in this report was to answer the question, 'If diversity is required in a safety system to mitigate the consequences of potential CCFs, how much diversity is enough?' The principal results of this research effort have identified and developed diversity strategies, which consist of combinations of diversity attributes and their associated criteria. Technology, which corresponds to design diversity, is chosen as the principal system characteristic by which diversity criteria are grouped to form strategies. The rationale for this classification framework involves consideration of the profound impact that technology-focused design diversity provides. Consequently, the diversity usage classification scheme involves three families of strategies: (1) different technologies, (2) different approaches within

  7. Diversity, occurrence and feeding traits of caddisfly larvae as indicators for ecological integrity of river-floodplain habitats along a connectivity gradient

    NARCIS (Netherlands)

    Van den Brink, F.W.B.; Van der Velde, G.; Wijnhoven, S.

    2013-01-01

    In order to assess ecological values of Lower Rhine and Meuse floodplain habitats we studied the spatial and seasonal variation in diversity, species assemblages and feeding traits of caddisfly larvae in water bodies over the lateral connectivity gradient: eupotamon: main and secondary channels: par

  8. The evolution of Paleozoic vascular land plant diversity of South China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Data of Paleozoic and some Early Triassic vascular land plant fossils from South China are synthetically analyzed,revealing evolutionary characteristics of Paleozoic vascular land plant diversity.Vascular land plant diversity keeps increasing in the Paleozoic as a whole.The Silurian witnessed the earliest evolution and initial diversification of land plants.From the Early Devonian to the Early Carboniferous(Mississippian),the great development,diversification,and differentiation really occurred in vascular land plants,with fluctuations of diversity,rapid replacement of the plant types,and an all-out takeover of terrestrial ecological niches.From the Early Permian,land plant diversity dramatically increased,and reached a climax in the Middle-Late Permian.Comparisons between late Paleozoic marine and terrestrial biodiversity reveal co-evolution of the late Paleozoic animals and plants as well as the individual evolutionary patterns of sea/land ecosystems.Vascular land plant diversity dramatically declined in the Frasnian as a result of the F/F event,and the end-Permian mass extinctions completely turned over the phytogroups.

  9. Mollusc and plant assemblages controlled by different ecological gradients at Eastern European fens

    Science.gov (United States)

    Schenková, Veronika; Horsák, Michal; Hájek, Michal; Plesková, Zuzana; Dítě, Daniel; Pawlikowski, Paweł

    2014-04-01

    Ecological patterns of mollusc assemblages and vegetation in relation to water chemistry, water regime, nutrient availability and climate were studied in eastern Polish lowland fens. Our goal was to examine if major compositional changes differ for molluscs and vegetation under the joint influence of multiple ecological gradients. Altogether 32 fen sites were investigated in 2010-2011, and analyzed using metric multidimensional scaling, cluster analysis and generalized additive models. Two major gradients driving the differences in mollusc species composition were revealed. The main direction of compositional changes was associated with the water table gradient, governing a species turnover from inundated and strongly water-logged sites occupied mostly by aquatic mollusc species, to moderately wet sites with the predominance of fen and meadow species. The second most important gradient for molluscs was that of mineral richness. For vegetation, three major gradients explained the changes in species composition. The highest importance was assigned to the nitrogen-to-phosphorus availability gradient (defined as a shift from N-limited to P-limited vegetation), followed by the water table gradient, and the mineral richness gradient. Our results demonstrate that the impact of mineral richness gradient, which has been often reported as the major determinant of compositional changes of fen molluscs and vegetation, can be exceeded by other ecological gradients of comparable variation. We also document for the first time that the main species turnover of fen vegetation is not accompanied by the analogous change in species composition of mollusc assemblages, due to a different sensitivity of these taxa to particular environmental factors (i.e. water level dynamics and type of nutrient limitation).

  10. Geographical patterns in the beta diversity of China's woody plants

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao

    2012-01-01

    Beta diversity (i.e. species turnover rate across space) is fundamental for understanding mechanisms controlling large-scale species richness patterns. However, the influences on beta diversity are still a matter of debate. In particular, the relative role of environmental and spatial processes (...

  11. Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields.

    Science.gov (United States)

    Martínez, Eliana; Rös, Matthias; Bonilla, María Argenis; Dirzo, Rodolfo

    2015-01-01

    The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

  12. Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields.

    Directory of Open Access Journals (Sweden)

    Eliana Martínez

    Full Text Available The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

  13. Experiment, monitoring, and gradient methods used to infer climate change effects on plant communities yield consistent patterns.

    Science.gov (United States)

    Elmendorf, Sarah C; Henry, Gregory H R; Hollister, Robert D; Fosaa, Anna Maria; Gould, William A; Hermanutz, Luise; Hofgaard, Annika; Jónsdóttir, Ingibjörg S; Jónsdóttir, Ingibjörg I; Jorgenson, Janet C; Lévesque, Esther; Magnusson, Borgþór; Molau, Ulf; Myers-Smith, Isla H; Oberbauer, Steven F; Rixen, Christian; Tweedie, Craig E; Walker, Marilyn D; Walker, Marilyn

    2015-01-13

    Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling along environmental gradients. Potential limitations of all three approaches are recognized. Here we address the congruence among these three main approaches by comparing the degree to which tundra plant community composition changes (i) in response to in situ experimental warming, (ii) with interannual variability in summer temperature within sites, and (iii) over spatial gradients in summer temperature. We analyzed changes in plant community composition from repeat sampling (85 plant communities in 28 regions) and experimental warming studies (28 experiments in 14 regions) throughout arctic and alpine North America and Europe. Increases in the relative abundance of species with a warmer thermal niche were observed in response to warmer summer temperatures using all three methods; however, effect sizes were greater over broad-scale spatial gradients relative to either temporal variability in summer temperature within a site or summer temperature increases induced by experimental warming. The effect sizes for change over time within a site and with experimental warming were nearly identical. These results support the view that inferences based on space-for-time substitution overestimate the magnitude of responses to contemporary climate warming, because spatial gradients reflect long-term processes. In contrast, in situ experimental warming and monitoring approaches yield consistent estimates of the magnitude of response of plant communities to climate warming.

  14. Environmental regulation of carbon isotope composition and crassulacean acid metabolism in three plant communities along a water availability gradient

    OpenAIRE

    2010-01-01

    Expression of crassulacean acid metabolism (CAM) is characterized by extreme variability within and between taxa and its sensitivity to environmental variation. In this study, we determined seasonal fluctuations in CAM photosynthesis with measurements of nocturnal tissue acidification and carbon isotopic composition (δ13C) of bulk tissue and extracted sugars in three plant communities along a precipitation gradient (500, 700, and 1,000 mm year−1) on the Yucatan Peninsula. We also related the ...

  15. Positive effects of plant genotypic and species diversity on anti-herbivore defenses in a tropical tree species.

    Directory of Open Access Journals (Sweden)

    Xoaquín Moreira

    Full Text Available Despite increasing evidence that plant intra- and inter-specific diversity increases primary productivity, and that such effect may in turn cascade up to influence herbivores, there is little information about plant diversity effects on plant anti-herbivore defenses, the relative importance of different sources of plant diversity, and the mechanisms for such effects. For example, increased plant growth at high diversity may lead to reduced investment in defenses via growth-defense trade-offs. Alternatively, positive effects of plant diversity on plant growth may lead to increased herbivore abundance which in turn leads to a greater investment in plant defenses. The magnitude of trait variation underlying diversity effects is usually greater among species than among genotypes within a given species, so plant species diversity effects on resource use by producers as well as on higher trophic levels should be stronger than genotypic diversity effects. Here we compared the relative importance of plant genotypic and species diversity on anti-herbivore defenses and whether such effects are mediated indirectly via diversity effects on plant growth and/or herbivore damage. To this end, we performed a large-scale field experiment where we manipulated genotypic diversity of big-leaf mahogany (Swietenia macrophylla and tree species diversity, and measured effects on mahogany growth, damage by the stem-boring specialist caterpillar Hypsipyla grandella, and defensive traits (polyphenolics and condensed tannins in stem and leaves. We found that both forms of plant diversity had positive effects on stem (but not leaf defenses. However, neither source of diversity influenced mahogany growth, and diversity effects on defenses were not mediated by either growth-defense trade-offs or changes in stem-borer damage. Although the mechanism(s of diversity effects on plant defenses are yet to be determined, our study is one of the few to test for and show producer

  16. Is plant temporal beta diversity of field margins related to changes in management practices?

    Science.gov (United States)

    Alignier, Audrey; Baudry, Jacques

    2016-08-01

    Field margins have considerable ecological significance in agriculture-dominated landscapes by supporting biodiversity and associated services. However, agricultural changes during mid-20th century led to their drastic loss with a serious threat for biodiversity. Using time-series data, we aimed to get better insights into processes underlying plant patterns of field margins through time by i) quantifying plant temporal beta diversity components, ii) assessing whether the observed changes in plant communities can be related to changes in management practices applied to field margins. During the springs of 1994, 1998 and 2001, we surveyed plant communities and management practices of the same 116 field margins in three contrasted landscapes. We estimated temporal beta diversity in plant communities and partitioned it into its two dissimilarity resultant components, accounting for replacement of species (i.e. turnover) and for the nested gain or loss of species (i.e. nestedness). We then tested whether the observed changes in plant communities between 1994 and 1998 and, between 1998 and 2001 were related to changes in management practices using linear models. Plant communities of field margins exhibited strong temporal beta diversity dominated by turnover. Temporal turnover in plant communities was partly related to changes in management practices, i.e., a decrease of grazing concomitant to an increase of herbicide spraying. However, relationships were not consistent between all landscape contexts nor time period, suggesting that other unmeasured deterministic or stochastic processes could be driving the observed plant patterns. Taken together, our results suggest that maintaining a wide diversity of field margins with contrasted management contribute to maintaining plant diversity at a landscape scale. They underline the value of investigating plant temporal diversity patterns using time-series data and thus, the need to develop long-term studies making it possible

  17. Plants Species Diversity in Hyrcanian Hardwood Forests, Northern Iran (Case Study: Mazandaran Province

    Directory of Open Access Journals (Sweden)

    Kambiz Abrari Vajari

    2013-12-01

    Full Text Available In order to better understand and manage forest ecosystems, it is important to study the relationship between environmental factors and plants in these ecosystems. We investigated plant species diversity of three hardwood forest stands in the Hyrcanian forests, Sari, northern Iran. Our aim was to determine the effect of forest stand type on the diversity of plant species. One plot 150 × 150 m established at the center of each forest stand and in each plot, nine subplots 50 × 50 m were selected. Diversity values (Richness, diversity and evenness indices were measured in five sample areas 0.01 ha per 50 × 50 m quadrates by estimating cover percentage of each species. The results showed that Geophytes (43.33% had the highest life form spectrum among species. JACCARD'S similarity index revealed that the highest values exist between Parrotia-Carpinus and Carpinus stands. All herb layer species diversity indices varied significantly among different forest stands. Cover percentage significantly positively correlated with diversity indices in Parrotia-Carpinus stand. Diversity and richness indices of herb-layers plants were significantly negatively correlated with cover percentage in Fagus stand. Correlation analysis between all diversity measures and cover percentage in Carpinus stand wasn't significant. The result of the present study revealed that species diversity in temperate broad-leaved deciduous forest was significantly influenced by forest stand type

  18. Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Yunzhao Li

    2014-01-01

    Full Text Available The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of βT and Jaccard’s coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion.

  19. Plant diversity partitioning in Mediterranean croplands: effects of farming intensity, field edge, and landscape context.

    Science.gov (United States)

    Concepción, Elena D; Fernández-González, Federico; Díaz, Mario

    2012-04-01

    Farmland biodiversity is affected by factors acting at various spatial scales. However, most studies to date have focused on the field or farm scales that only account for local (alpha) diversity, and these may underestimate the contribution of other diversity components (beta diversity) to total (gamma) farmland diversity. In this work, we aimed to identify the most suitable management options and the scale at which they should be implemented to maximize benefits for diversity. We used a multi-scale additive partitioning approach, with data on plant diversity from 640 plots in 32 cereal crop fields from three agricultural regions of central Spain that differed in landscape configuration. We analyzed the relative contribution to overall plant diversity of different diversity components at various spatial scales and how these diversity components responded to a set of local (application of agri-environment schemes [AES] and position within the field) and landscape (field size and landscape connectivity and composition) factors. Differences in species composition among regions and then among fields within regions contributed most to overall plant diversity. Positive edge effects were found on all diversity components at both the field- and regional scales, whereas application of AES benefited all diversity components only at the field scale. Landscape factors had strong influences on plant diversity, especially length of seminatural boundaries, which increased species richness at both the field and the regional scales. In addition, positive effects of percentage of nonproductive land-uses in the landscape were found on all diversity components at the regional scale. Results showed that components that contributed most to overall plant diversity were not benefited by current AES. We conclude that agri-environmental policies should incorporate and prioritize measures aimed at the maintenance of seminatural boundaries and patches of nonproductive habitats within

  20. Do biotic interactions modulate ecosystem functioning along stress gradients? Insights from semi-arid plant and biological soil crust communities

    Science.gov (United States)

    Maestre, Fernando T.; Bowker, Matthew A.; Escolar, Cristina; Puche, María D.; Soliveres, Santiago; Maltez-Mouro, Sara; García-Palacios, Pablo; Castillo-Monroy, Andrea P.; Martínez, Isabel; Escudero, Adrián

    2010-01-01

    Climate change will exacerbate the degree of abiotic stress experienced by semi-arid ecosystems. While abiotic stress profoundly affects biotic interactions, their potential role as modulators of ecosystem responses to climate change is largely unknown. Using plants and biological soil crusts, we tested the relative importance of facilitative–competitive interactions and other community attributes (cover, species richness and species evenness) as drivers of ecosystem functioning along stress gradients in semi-arid Mediterranean ecosystems. Biotic interactions shifted from facilitation to competition along stress gradients driven by water availability and temperature. These changes were, however, dependent on the spatial scale and the community considered. We found little evidence to suggest that biotic interactions are a major direct influence upon indicators of ecosystem functioning (soil respiration, organic carbon, water-holding capacity, compaction and the activity of enzymes related to the carbon, nitrogen and phosphorus cycles) along stress gradients. However, attributes such as cover and species richness showed a direct effect on ecosystem functioning. Our results do not agree with predictions emphasizing that the importance of plant–plant interactions will be increased under climate change in dry environments, and indicate that reductions in the cover of plant and biological soil crust communities will negatively impact ecosystems under future climatic conditions. PMID:20513714

  1. Plant pathogens but not antagonists change in soil fungal communities across a land abandonment gradient in a Mediterranean landscape

    Science.gov (United States)

    Bosso, L.; Lacatena, F.; Varlese, R.; Nocerino, S.; Cristinzio, G.; Russo, D.

    2017-01-01

    We assessed whether the presence and abundance of plant pathogens and antagonists change in soil fungal communities along a land abandonment gradient. The study was carried out in the Cilento area (Southern Italy) at a site with three different habitats found along a land abandonment gradient: agricultural land, Mediterranean shrubland and woodland. For all microbiological substrates the colony forming units were about 3.1 × 106 g-1 soil for agricultural land and about 1.1 × 106 g-1 soil for Mediterranean shrubland and woodland. We found the following genera in all habitats: Cladosporium, Mortierella, Penicillium and Trichoderma. In agricultural land, the significantly most abundant fungus genera were Aspergillus, Fusarium, Cylindrocarpon and Nectria; in Mediterranean shrubland, Rhizopus and Trichoderma; and in woodland, Bionectria, Mortierella, Cladosporium, Diplodia, Paecilomyces, Penicillium and Trichoderma. We found a total of 8, 8 and 9 species of fungal antagonist, and 16, 6 and 6 species of fungal plant pathogens in agricultural land, Mediterranean shrubland and woodland respectively. Fungal plant pathogens decreased significantly over a land abandonment gradient, while we no found significant differences among fungal antagonists in the three habitats. We conclude that a decrease in the number of fungal pathogen species occurs when formerly cultivated areas are abandoned. On the other hand, fungal antagonists seem not to be affected by this process.

  2. Microbiome interplay: plants alter microbial abundance and diversity within the built environment.

    Science.gov (United States)

    Mahnert, Alexander; Moissl-Eichinger, Christine; Berg, Gabriele

    2015-01-01

    The built indoor microbiome has importance for human health. Residents leave their microbial fingerprint but nothing is known about the transfer from plants. Our hypothesis that indoor plants contribute substantially to the microbial abundance and diversity in the built environment was experimentally confirmed as proof of principle by analyzing the microbiome of the spider plant Chlorophytum comosum in relation to their surroundings. The abundance of Archaea, Bacteria, and Eukaryota (fungi) increased on surrounding floor and wall surfaces within 6 months of plant isolation in a cleaned indoor environment, whereas the microbial abundance on plant leaves and indoor air remained stable. We observed a microbiome shift: the bacterial diversity on surfaces increased significantly but fungal diversity decreased. The majority of cells were intact at the time of samplings and thus most probably alive including diverse Archaea as yet unknown phyllosphere inhabitants. LEfSe and network analysis showed that most microbes were dispersed from plant leaves to the surrounding surfaces. This led to an increase of specific taxa including spore-forming fungi with potential allergic potential but also beneficial plant-associated bacteria, e.g., Paenibacillus. This study demonstrates for the first time that plants can alter the microbiome of a built environment, which supports the significance of plants and provides insights into the complex interplay of plants, microbiomes and human beings.

  3. Microbiome interplay: plants alter microbial abundance and diversity within the built environment

    Directory of Open Access Journals (Sweden)

    Alexander eMahnert

    2015-08-01

    Full Text Available The built indoor microbiome has importance for human health. Residents leave their microbial fingerprint but nothing is known about the transfer from plants. Our hypothesis that indoor plants contribute substantially to the microbial abundance and diversity in the built environment was experimentally confirmed as proof of principle by analyzing the microbiome of the spider plant Chlorophytum comosum in relation to their surroundings. The abundance of Archaea, Bacteria and Eukaryota (fungi increased on surrounding floor and wall surfaces within six months of plant isolation in a cleaned indoor environment, whereas the microbial abundance on plant leaves and indoor air remained stable. We observed a microbiome shift: the bacterial diversity on surfaces increased significantly but fungal diversity decreased. The majority of cells were intact at the time of samplings and thus most probably alive including diverse Archaea as yet unknown phyllosphere inhabitants. LEfSe and network analysis showed that most microbes were dispersed from plant leaves to the surrounding surfaces. This led to an increase of specific taxa including spore-forming fungi with potential allergic potential but also beneficial plant-associated bacteria, e.g. Paenibacillus. This study demonstrates for the first time that plants can alter the microbiome of a built environment, which supports the significance of plants and provides insights into the complex interplay of plants, microbiomes and human beings.

  4. Classification and ordination of main plant communities along an altitudinal gradient in the arid and temperate climates of northeastern Mexico.

    Science.gov (United States)

    Castillón, Eduardo Estrada; Arévalo, José Ramón; Quintanilla, José Ángel Villarreal; Rodríguez, María Magdalena Salinas; Encina-Domínguez, Juan Antonio; Rodríguez, Humberto González; Ayala, César Martín Cantú

    2015-10-01

    Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.

  5. Impact of urbanization on plant diversity: A case study in built-up areas of Beijing

    Institute of Scientific and Technical Information of China (English)

    LIANG Yao-qin; LI Jing-wen; LI Jing; Sanna Katrina VALIMAKI

    2008-01-01

    Urbanization is developing rapidly in the world, which seriously changes the habitat of organisms and has clearly a negative effect on biodiversity. Preservation of biodlversity is crucial in urban planning and management, which is also an important symbol for the level of greening. Problems such as scarcity of urban green space and plant species have become obstacles to the establishment of ecological friendly cities. However, coexistence of nature and modernization, as well the coordination of economic development and biodiversity, are goals that people are seeking. We have taken the built-up areas of Beijing as a study case and discussed the impacts of urbanization on plant diversity, with the support of fieldwork and SPOT remote sensing data. The results are as follows: 1) in the process of urbanization, exotic plants have been widely introduced, which has affected species composition and the proportion of native plants; it is clear that artificial green spaces always will have a lower level of plant diversity than natural green spaces; 2) functional differences of green space types partially decide their species abundance, so that plant diversity in greenbelts and streets is generally lower than in parks; 3) the spatial variety of plant diversity contributes much to the imbalance of district development and the planning of different functional zones; this variation is embodied in different ring-belts and directions; 4) habitat fragmentation also affects plant diversity to a great extent; there is a significant positive correlation between high fragmentation and low plant diversity. According our results, some suggestions are proposed, which would be suitable for the preservation of plant diversity and ecological improvement during urbanization.

  6. Seed plant phylogenetic diversity and species richness in conservation planning within a global biodiversity hotspot in eastern Asia.

    Science.gov (United States)

    Li, Rong; Kraft, Nathan J B; Yu, Haiying; Li, Heng

    2015-12-01

    One of the main goals of conservation biology is to understand the factors shaping variation in biodiversity across the planet. This understanding is critical for conservation planners to be able to develop effective conservation strategies. Although many studies have focused on species richness and the protection of rare and endemic species, less attention has been paid to the protection of the phylogenetic dimension of biodiversity. We explored how phylogenetic diversity, species richness, and phylogenetic community structure vary in seed plant communities along an elevational gradient in a relatively understudied high mountain region, the Dulong Valley, in southeastern Tibet, China. As expected, phylogenetic diversity was well correlated with species richness among the elevational bands and among communities. At the community level, evergreen broad-leaved forests had the highest levels of species richness and phylogenetic diversity. Using null model analyses, we found evidence of nonrandom phylogenetic structure across the region. Evergreen broad-leaved forests were phylogenetically overdispersed, whereas other vegetation types tended to be phylogenetically clustered. We suggest that communities with high species richness or overdispersed phylogenetic structure should be a focus for biodiversity conservation within the Dulong Valley because these areas may help maximize the potential of this flora to respond to future global change. In biodiversity hotspots worldwide, we suggest that the phylogenetic structure of a community may serve as a useful measure of phylogenetic diversity in the context of conservation planning. © 2015 Society for Conservation Biology.

  7. Diversity of planktonic fish larvae along a latitudinal gradient in the Eastern Atlantic Ocean estimated through DNA barcodes

    Directory of Open Access Journals (Sweden)

    Alba Ardura

    2016-10-01

    Full Text Available Mid-trophic pelagic fish are essential components of marine ecosystems because they represent the link between plankton and higher predators. Moreover, they are the basis of the most important fisheries resources; for example, in African waters. In this study, we have sampled pelagic fish larvae in the Eastern Atlantic Ocean along a latitudinal gradient between 37°N and 2°S. We have employed Bongo nets for plankton sampling and sorted visually fish and fish larvae. Using the cytochrome oxidase I gene (COI as a DNA barcode, we have identified 44 OTUs down to species level that correspond to 14 families, with Myctophidae being the most abundant. A few species were cosmopolitan and others latitude-specific, as was expected. The latitudinal pattern of diversity did not exhibit a temperate-tropical cline; instead, it was likely correlated with environmental conditions with a decline in low-oxygen zones. Importantly, gaps and inconsistencies in reference DNA databases impeded accurate identification to the species level of 49% of the individuals. Fish sampled from tropical latitudes and some orders, such as Perciformes, Myctophiformes and Stomiiformes, were largely unidentified due to incomplete references. Some larvae were identified based on morphology and COI analysis for comparing time and costs employed from each methodology. These results suggest the need of reinforcing DNA barcoding reference datasets of Atlantic bathypelagic tropical fish that, as main prey of top predators, are crucial for ecosystem-based management of fisheries resources.

  8. Application of temperature gradient gel electrophoresis to the study of yeast diversity in the estuary of the Tagus river, Portugal.

    Science.gov (United States)

    Gadanho, Mário; Sampaio, José Paulo

    2004-12-01

    Temperature gradient gel electrophoresis (TGGE) was employed for the assessment of yeast diversity in the estuary of the Tagus river (Portugal). The molecular detection of yeasts was carried out directly from water samples and, in parallel, a cultivation approach by means of an enrichment step was employed. A nested PCR was employed to obtain a fungal amplicon containing the D2 domain of the 26S rRNA gene. For identification the TGGE bands were extracted, re-amplified, and sequenced. Fourteen fungal taxa were detected and all except one were yeasts. Most yeast sequences corresponded to members of the Ascomycota and only three belonged to the Basidiomycota. Five yeasts (four ascomycetes and one basidiomycete) could not be identified to the species level due to the uniqueness of their sequences. The number of species detected after enrichment was higher than the number of taxa found using the direct detection method. This suggests that some yeast populations are present in densities that are below the detection threshold of the method. With respect to the analysis of the yeast community structure, our results indicate that the dominant populations belong to Debaryomyces hansenii, Rhodotorula mucilaginosa, Cryptococcus longus, and to an uncultured basidiomycetous yeast phylogenetically close to Cr. longus. The combined analysis of direct detection and cultivation approaches indicates a similar community structure at the two sampled sites since nine species were present at both localities.

  9. Diversity of planktonic fish larvae along a latitudinal gradient in the Eastern Atlantic Ocean estimated through DNA barcodes

    Science.gov (United States)

    Morote, Elvira; Kochzius, Marc; Garcia-Vazquez, Eva

    2016-01-01

    Mid-trophic pelagic fish are essential components of marine ecosystems because they represent the link between plankton and higher predators. Moreover, they are the basis of the most important fisheries resources; for example, in African waters. In this study, we have sampled pelagic fish larvae in the Eastern Atlantic Ocean along a latitudinal gradient between 37°N and 2°S. We have employed Bongo nets for plankton sampling and sorted visually fish and fish larvae. Using the cytochrome oxidase I gene (COI) as a DNA barcode, we have identified 44 OTUs down to species level that correspond to 14 families, with Myctophidae being the most abundant. A few species were cosmopolitan and others latitude-specific, as was expected. The latitudinal pattern of diversity did not exhibit a temperate-tropical cline; instead, it was likely correlated with environmental conditions with a decline in low-oxygen zones. Importantly, gaps and inconsistencies in reference DNA databases impeded accurate identification to the species level of 49% of the individuals. Fish sampled from tropical latitudes and some orders, such as Perciformes, Myctophiformes and Stomiiformes, were largely unidentified due to incomplete references. Some larvae were identified based on morphology and COI analysis for comparing time and costs employed from each methodology. These results suggest the need of reinforcing DNA barcoding reference datasets of Atlantic bathypelagic tropical fish that, as main prey of top predators, are crucial for ecosystem-based management of fisheries resources. PMID:27761307

  10. Habitat fragmentation, tree diversity, and plant invasion interact to structure forest caterpillar communities.

    Science.gov (United States)

    Stireman, John O; Devlin, Hilary; Doyle, Annie L

    2014-09-01

    Habitat fragmentation and invasive species are two of the most prominent threats to terrestrial ecosystems. Few studies have examined how these factors interact to influence the diversity of natural communities, particularly primary consumers. Here, we examined the effects of forest fragmentation and invasion of exotic honeysuckle (Lonicera maackii, Caprifoliaceae) on the abundance and diversity of the dominant forest herbivores: woody plant-feeding Lepidoptera. We systematically surveyed understory caterpillars along transects in 19 forest fragments over multiple years in southwestern Ohio and evaluated how fragment area, isolation, tree diversity, invasion by honeysuckle and interactions among these factors influence species richness, diversity and abundance. We found strong seasonal variation in caterpillar communities, which responded differently to fragmentation and invasion. Abundance and richness increased with fragment area, but these effects were mitigated by high levels of honeysuckle, tree diversity, landscape forest cover, and large recent changes in area. Honeysuckle infestation was generally associated with decreased caterpillar abundance and diversity, but these effects were strongly dependent on other fragment traits. Effects of honeysuckle on abundance were moderated when fragment area, landscape forest cover and tree diversity were high. In contrast, negative effects of honeysuckle invasion on caterpillar diversity were most pronounced in fragments with high tree diversity and large recent increases in area. Our results illustrate the complex interdependencies of habitat fragmentation, plant diversity and plant invasion in their effects on primary consumers and emphasize the need to consider these processes in concert to understand the consequences of anthropogenic habitat change for biodiversity.

  11. PLANT DIVERSITY OF THE ZHELTOKAMENSKIY OPEN CAST MINES

    Directory of Open Access Journals (Sweden)

    Yarova T.A.

    2012-11-01

    Full Text Available Floristic structure data of soil algae, lichens, mosses, and vascular plants are given. Rare plant species which are protected at the Ukrainian, European, and International levels were revealed. The species list of trees and bushes was conducted. The soil analysis was carried out by such parameters: pH-value, the maintenance of hygroscopic water, the maintenance of mineral substances. Vegetation biomass on the open cast mines sample areas is defined. Ecological analysis of the biotopes of registered algae species was performed. The ecological analysis of the vascular plants species biotopes was carried out.The estimation of the perspective vegetation pattern was suggested for natural restoration of the open cast mines. The plant species are selected according to the ecological and morphological characteristics for plant rehabilitation and planting of open cast mines.

  12. Forest species diversity reduces disease risk in a generalist plant pathogen invasion

    Science.gov (United States)

    Haas, Sarah E.; Hooten, Mevin B.; Rizzo, David M.; Meentemeyer, Ross K.

    2011-01-01

    Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.

  13. Exploring Genetic Diversity in Plants Using High-Throughput Sequencing Techniques.

    Science.gov (United States)

    Onda, Yoshihiko; Mochida, Keiichi

    2016-08-01

    Food security has emerged as an urgent concern because of the rising world population. To meet the food demands of the near future, it is required to improve the productivity of various crops, not just of staple food crops. The genetic diversity among plant populations in a given species allows the plants to adapt to various environmental conditions. Such diversity could therefore yield valuable traits that could overcome the food-security challenges. To explore genetic diversity comprehensively and to rapidly identify useful genes and/or allele, advanced high-throughput sequencing techniques, also called next-generation sequencing (NGS) technologies, have been developed. These provide practical solutions to the challenges in crop genomics. Here, we review various sources of genetic diversity in plants, newly developed genetic diversity-mining tools synergized with NGS techniques, and related genetic approaches such as quantitative trait locus analysis and genome-wide association study.

  14. Generalist birds promote tropical forest regeneration and increase plant diversity via rare-biased seed dispersal.

    Science.gov (United States)

    Carlo, Tomás A; Morales, Juan M

    2016-07-01

    Regenerated forests now compose over half of the world's tropical forest cover and are increasingly important as providers of ecosystem services, freshwater, and biodiversity conservation. Much of the value and functionality of regenerating forests depends on the plant diversity they contain. Tropical forest diversity is strongly shaped by mutualistic interactions between plants and fruit-eating animals (frugivores) that disperse seeds. Here we show how seed dispersal by birds can influence the speed and diversity of early successional forests in Puerto Rico. For two years, we monitored the monthly fruit production of bird-dispersed plants on a fragmented landscape, and measured seed dispersal activity of birds and plant establishment in experimental plots located in deforested areas. Two predominantly omnivorous bird species, the Northern Mockingbird (Mimus polyglottos) and the Gray Kingbird (Tyrannus dominicensis), proved critical for speeding up the establishment of woody plants and increasing the species richness and diversity of the seed rain in deforested areas. Seed dispersal by these generalists increased the odds for rare plant species to disperse and establish in experimental forest-regeneration plots. Results indicate that birds that mix fruit and insects in their diets and actively forage across open and forested habitats can play keystone roles in the regeneration of mutualistic plant-animal communities. Furthermore, our analyses reveal that rare-biased (antiapostatic) frugivory and seed dispersal is the mechanism responsible for increasing plant diversity in the early-regenerating community. © 2016 by the Ecological Society of America.

  15. Diversity of ABC transporter genes across the plant kingdom and their potential utility in biotechnology.

    Science.gov (United States)

    Lane, Thomas S; Rempe, Caroline S; Davitt, Jack; Staton, Margaret E; Peng, Yanhui; Soltis, Douglas Edward; Melkonian, Michael; Deyholos, Michael; Leebens-Mack, James H; Chase, Mark; Rothfels, Carl J; Stevenson, Dennis; Graham, Sean W; Yu, Jun; Liu, Tao; Pires, J Chris; Edger, Patrick P; Zhang, Yong; Xie, Yinlong; Zhu, Ying; Carpenter, Eric; Wong, Gane Ka-Shu; Stewart, C Neal

    2016-05-31

    The ATP-binding cassette (ABC) transporter gene superfamily is ubiquitous among extant organisms and prominently represented in plants. ABC transporters act to transport compounds across cellular membranes and are involved in a diverse range of biological processes. Thus, the applicability to biotechnology is vast, including cancer resistance in humans, drug resistance among vertebrates, and herbicide and other xenobiotic resistance in plants. In addition, plants appear to harbor the highest diversity of ABC transporter genes compared with any other group of organisms. This study applied transcriptome analysis to survey the kingdom-wide ABC transporter diversity in plants and suggest biotechnology applications of this diversity. We utilized sequence similarity-based informatics techniques to infer the identity of ABC transporter gene candidates from 1295 phylogenetically-diverse plant transcriptomes. A total of 97,149 putative (approximately 25 % were full-length) ABC transporter gene members were identified; each RNA-Seq library (plant sample) had 88 ± 30 gene members. As expected, simpler organisms, such as algae, had fewer unique members than vascular land plants. Differences were also noted in the richness of certain ABC transporter subfamilies. Land plants had more unique ABCB, ABCC, and ABCG transporter gene members on average (p plant groups (p plant groups. An increase in the number of gene family members present in the ABCB, ABCC, and ABCD transporter subfamilies may indicate an expansion of the ABC transporter superfamily among green land plants, which include all crop species. The striking difference between the number of ABCA subfamily transporter gene members between ferns and other plant taxa is surprising and merits further investigation. Discussed is the potential exploitation of ABC transporters in plant biotechnology, with an emphasis on crops.

  16. Soil microbes contribute to the classic plant diversity-productivity pattern

    NARCIS (Netherlands)

    Schnitzer, S.A.; Klironomos, J.N.; HilleRisLambers, J.; Kinkel, L.L.; Reich, P.B.; Nes, van E.H.; Scheffer, M.

    2011-01-01

    Ecosystem productivity commonly increases asymptotically with plant species diversity, and determining the mechanisms responsible for this well-known pattern is essential to predict potential changes in ecosystem productivity with ongoing species loss. Previous studies attributed the asymptotic dive

  17. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    C. Jeanthon

    2011-07-01

    Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a, the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 % was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired...... native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity...

  19. Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Doethideomycetes Fungi

    Energy Technology Data Exchange (ETDEWEB)

    Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabien; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; de Wit, Pierre J. G. M.; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

    2012-03-13

    The class of Dothideomycetes is one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related species can have very diverse host plants. Eighteen genomes of Dothideomycetes have currently been sequenced by the Joint Genome Institute and other sequencing centers. Here we describe the results of comparative analyses of the fungi in this group.

  20. Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Dothideomycetes

    Energy Technology Data Exchange (ETDEWEB)

    Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabian; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; de Wit, Pierre J. G. M.; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

    2013-03-05

    The class of Dothideomycetes is one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops that are grown for biofuel, food or feed. Most Dothideomycetes have only a single host plant, and related species can have very diverse hosts. Eighteen genomes of Dothideomycetes have currently been sequenced by the Joint Genome Institute and other sequencing centers. Here we describe the results of comparative analyses of the fungi in this group.

  1. Divergence of above- and belowground C and N pool within predominant plant species along two precipitation gradients in North China

    Science.gov (United States)

    Ye, X. H.; Pan, X.; Cornwell, W. K.; Gao, S. Q.; Dong, M.; Cornelissen, J. H. C.

    2015-01-01

    The coupling of carbon cycle and nitrogen cycle drives the food web structure and biogeochemistry of an ecosystem. However, across precipitation gradients, there may be a shift in C pool and N pool from above- to belowground because of shifting plant stoichiometry and allocation. Based on previous evidence, biomass allocation to roots should increase with aridity, while leaf [N] should increase. If their effect sizes are equal, they should cancel each other out, and the above- and belowground proportions of the N would remain constant. Here, we present the first study to explicitly compare above- and belowground pool sizes of N and C within predominant plant species along precipitation gradients. Biomass and nutrient concentrations of leaves, stems and roots of three predominant species were measured along two major precipitation gradients in Inner Mongolia, China. Along the two gradients, the effect sizes of the biomass shifts were remarkably consistent among three predominant species. However, the size of the shift in aboveground [N] was not, leading to a species-specific pattern in above- and belowground pool size. In two species (Stipa grandis and Artemisia ordosica) the effect sizes of biomass allocation and [N] were equal and the proportion of N of above- and belowground did not change with aridity, but in S. bungeana the increase in leaf [N] with aridity was much weaker than the biomass shift, leading to a decrease in the proportion of N aboveground at dry sites. We have found examples of consistent N pool sizes above- and belowground and a shift to a greater proportion of belowground N in drier sites depending on the species. We suggest that precipitation gradients do potentially decouple the C and N pool, but the exact nature of the decoupling depends on the dominant species' capacity for intraspecific variation.

  2. Divergence of above- and belowground C and N pool within predominant plant species along two precipitation gradients in north China

    Directory of Open Access Journals (Sweden)

    X. H. Ye

    2014-10-01

    Full Text Available The coupling of carbon cycle and nutrient cycle drives food web structure and biogeochemistry of an ecosystem. However, across precipitation gradients, there may be a shift in C pool and N pool from above- to belowground because of shifting plant stoichiometry and allocation. Based on previous evidence, biomass allocation to roots should increase with aridity, while leaf [N] should increase. If their effect sizes are equal, they should cancel each other out, and the above- and belowground proportions of the N would remain constant. Here, we present the first study to explicitly compare above- and belowground pool sizes of N and C within predominant plant species along precipitation gradients. Biomass and nutrient concentrations of leaves, stems and roots of three predominant species were measured along two major precipitation gradients in Inner Mongolia, China. Along the two gradients, the effect sizes of the biomass shifts were remarkably consistent among three predominant species. However, the size of the shift in aboveground [N] was not, leading to a species-specific pattern in above- and belowground pool size. In two species (Stipa grandis and Artemisia ordosica the effect sizes of biomass allocation and [N] were equal and the proportion of N of above- and belowground did not change with aridity, but in S. bungeana the increase in leaf [N] with aridity was much weaker than the biomass shift, leading to a decrease in the proportion of N belowground at dry sites. We have found examples of consistent N pool sizes above- and belowground and a shift to a greater proportion of belowground N in drier sites depending on the species. We suggest that precipitation gradients do potentially decouple the C and N pool, but the exact nature of the decoupling depends on the dominant species' capacity for intraspecific variation.

  3. Restoration and management for plant diversity enhances the rate of belowground ecosystem recovery.

    Science.gov (United States)

    Klopf, Ryan P; Baer, Sara G; Bach, Elizabeth M; Six, Johan

    2017-03-01

    The positive relationship between plant diversity and ecosystem functioning has been criticized for its applicability at large scales and in less controlled environments that are relevant to land management. To inform this gap between ecological theory and application, we compared recovery rates of belowground properties using two chronosequences consisting of continuously cultivated and independently restored fields with contrasting diversity management strategies: grasslands restored with high plant richness and managed for diversity with frequent burning (n = 20) and grasslands restored with fewer species that were infrequently burned (n = 15). Restoration and management for plant diversity resulted in 250% higher plant richness. Greater recovery of roots and more predictable recovery of the active microbial biomass across the high diversity management strategy chronosequence corresponded with faster recovery of soil structure. The high diversity grasslands also had greater nutrient conservation indicated by lower available inorganic nitrogen. Thus, mesic grasslands restored with more species and managed for high plant diversity with frequent burning enhances the rate of belowground ecosystem recovery from long-term disturbance at a scale relevant to conservation practices on the landscape.

  4. On the factors that promote the diversity of herbivorous insects and plants in tropical forests.

    Science.gov (United States)

    Becerra, Judith X

    2015-05-12

    Some of the most fascinating and challenging questions in ecology are why biodiversity is highest in tropical forests and whether the factors involved are unique to these habitats. I did a worldwide test of the hypotheses that plant community divergence in antiherbivore traits results in higher insect herbivore diversity, and that predominant attack by specialized herbivores promotes plant richness. I found strong correlative support for both ideas. Butterfly diversity was greatest in regions where the community average species-pairwise dissimilarity in antiherbivore traits among plant species was highest. There was also a strong positive relationship between specialized (insect) vs. generalized (mammal) herbivores and plant richness. Regions where herbivory impact by mammals was higher than that of insects tended to have lower plant diversities. In contrast, regions in which insects are the main consumers, particularly in the Central and South American tropics, had the highest plant richness. Latitude did not explain any residual variance in insect or plant richness. The strong connections found between insect specialization, plant defense divergence, and plant and insect diversities suggest that increasing our understanding of the ecology of biological communities can aid in considerations of how to preserve biodiversity in the future.

  5. Plant diversity and functional groups affect Si and Ca pools in aboveground biomass of grassland systems.

    Science.gov (United States)

    Schaller, Jörg; Roscher, Christiane; Hillebrand, Helmut; Weigelt, Alexandra; Oelmann, Yvonne; Wilcke, Wolfgang; Ebeling, Anne; Weisser, Wolfgang W

    2016-09-01

    Plant diversity is an important driver of nitrogen and phosphorus stocks in aboveground plant biomass of grassland ecosystems, but plant diversity effects on other elements also important for plant growth are less understood. We tested whether plant species richness, functional group richness or the presence/absence of particular plant functional groups influences the Si and Ca concentrations (mmol g(-1)) and stocks (mmol m(-2)) in aboveground plant biomass in a large grassland biodiversity experiment (Jena Experiment). In the experiment including 60 temperate grassland species, plant diversity was manipulated as sown species richness (1, 2, 4, 8, 16) and richness and identity of plant functional groups (1-4; grasses, small herbs, tall herbs, legumes). We found positive species richness effects on Si as well as Ca stocks that were attributable to increased biomass production. The presence of particular functional groups was the most important factor explaining variation in aboveground Si and Ca stocks (mmol m(-2)). Grass presence increased the Si stocks by 140 % and legume presence increased the Ca stock by 230 %. Both the presence of specific plant functional groups and species diversity altered Si and Ca stocks, whereas Si and Ca concentration were affected mostly by the presence of specific plant functional groups. However, we found a negative effect of species diversity on Si and Ca accumulation, by calculating the deviation between mixtures and mixture biomass proportions, but in monoculture concentrations. These changes may in turn affect ecosystem processes such as plant litter decomposition and nutrient cycling in grasslands.

  6. Molecular diversity at the plant-pathogen interface.

    Science.gov (United States)

    McDowell, John M; Simon, Stacey A

    2008-01-01

    Plants have evolved a robust innate immune system that exhibits striking similarities as well as significant differences with various metazoan innate immune systems. For example, plants are capable of perceiving pathogen-associated molecular patterns through pattern recognition receptors that bear structural similarities to animal Toll-like receptors. In addition, plants have evolved a second surveillance system based on cytoplasmic "NB-LRR" proteins (nucleotide-binding, leucine-rich repeat) that are structurally similar to animal nucleotide-binding and oligomerization domain (NOD)-like receptors. Plant NB-LRR proteins do not detect PAMPs; rather, they perceive effector proteins that pathogens secrete into plant cells to promote virulence. This review summarizes the current state of knowledge about the molecular functionality and evolution of these immune surveillance genes.

  7. Woody plant encroachment effect on soil organic carbon dynamics: results from a latitudinal gradient in Italy

    Science.gov (United States)

    Pellis, Guido; Chiti, Tommaso; Moscatelli, Maria Cristina; Marinari, Sara; Papale, Dario

    2016-04-01

    Woody plant encroachment into pastures and grasslands represents a significant land cover change phenomenon, with a considerable impact on carbon dynamics at an ecosystem level. It was estimated that 7.64% of the Southern Europe land was subject to that process between 1950 to 2010. As a result of woody encroachment, changes in vegetation composition can produce substantial changes to the soil organic carbon (SOC) cycle. Despite the numerous papers published on land-use change, an evaluation of the IPCC terrestrial carbon pools changes occurring during woody encroachment on abandoned pastures and grasslands is still lacking, particularly for the Italian territory. Therefore, the aim of this study was to investigate the role of woody encroachment on carbon sequestration over abandoned pastures and grasslands in Alpine and Apennine ecosystems, with a particular focus on the SOC. We applied a chronosequence approach to seven selected sites located along a latitudinal gradient in Italy. Each chronosequence consisted of a pasture currently managed, three sites abandoned at different times in the past and, finally, a mature forest stand representing the last phase of the succession. The European Commission sampling protocols to certify SOC changes was adopted to estimate the variations following woody encroachment. Soil samples were collected at different depths in the topsoil (0-30 cm) and subsoil (30-70 cm), despite the original protocol formulation being limited to the topsoil only. In addition, aboveground living biomass (AGB), dead wood and litter were also measured following international protocols. Considering all C pools together, woody plant encroachment leads to a progressive C stock accumulation in all the chronosequences. The total C stock of mature forest stands ranges from 1.78±0.11 times (Eastern Alps) to 2.48±0.31 times (central Apennine) the initial value on pastures. Unsurprisingly, the C stocks of AGB, dead wood and litter all increase during the

  8. Generic and functional diversity in endophytic actinomycetes from wild Compositae plant species at South Sinai - Egypt.

    Science.gov (United States)

    El-Shatoury, Sahar A; El-Kraly, Omnia A; Trujillo, Martha E; El-Kazzaz, Waleed M; El-Din, El-Sayeda Gamal; Dewedar, Ahmed

    2013-09-01

    The diversity of culturable endophytic actinomycetes associated with wild Compositae plants is scantily explored. In this study, one hundred and thirty one endophytic actinobacteria were isolated from ten Compositae plant species collected from South Sinai in Egypt. Microscopic and chemotaxonomic investigation of the isolates indicated fourteen genera. Rare genera, such as Microtetraspora, and Intrasporangium, which have never been previously reported to be endophytic, were identified. Each plant species accommodated between three to eight genera of actinobacteria and unidentified strains were recovered from seven plant species. The generic diversity analysis of endophytic assemblages grouped the plant species into three main clusters, representing high, moderate and low endophytic diversity. The endophytes showed high functional diversity, based on forty four catabolic and plant growth promotion traits; providing some evidence that such traits could represent key criteria for successful residence of endophytes in the endosphere. Stress-tolerance traits were more predictive measure of functional diversity differences between the endophyte assemblages (Shannon's index, p = 0.01). The results indicate a potential prominent role of endophytes for their hosts and emphasize the potency of plant endosphere as a habitat for actinobacteria with promising future applications.

  9. Diversity, classification and function of the plant protein kinase superfamily.

    Science.gov (United States)

    Lehti-Shiu, Melissa D; Shiu, Shin-Han

    2012-09-19

    Eukaryotic protein kinases belong to a large superfamily with hundreds to thousands of copies and are components of essentially all cellular functions. The goals of this study are to classify protein kinases from 25 plant species and to assess their evolutionary history in conjunction with consideration of their molecular functions. The protein kinase superfamily has expanded in the flowering plant lineage, in part through recent duplications. As a result, the flowering plant protein kinase repertoire, or kinome, is in general significantly larger than other eukaryotes, ranging in size from 600 to 2500 members. This large variation in kinome size is mainly due to the expansion and contraction of a few families, particularly the receptor-like kinase/Pelle family. A number of protein kinases reside in highly conserved, low copy number families and often play broadly conserved regulatory roles in metabolism and cell division, although functions of plant homologues have often diverged from their metazoan counterparts. Members of expanded plant kinase families often have roles in plant-specific processes and some may have contributed to adaptive evolution. Nonetheless, non-adaptive explanations, such as kinase duplicate subfunctionalization and insufficient time for pseudogenization, may also contribute to the large number of seemingly functional protein kinases in plants.

  10. Photosynthetic diversity meets biodiversity: the C4 plant example.

    Science.gov (United States)

    Sage, Rowan F; Stata, Matt

    2015-01-01

    Physiological diversification reflects adaptation for specific environmental challenges. As the major physiological process that provides plants with carbon and energy, photosynthesis is under strong evolutionary selection that gives rise to variability in nearly all parts of the photosynthetic apparatus. Here, we discuss how plants, notably those using C4 photosynthesis, diversified in response to environmental challenges imposed by declining atmospheric CO2 content in recent geological time. This reduction in atmospheric CO2 increases the rate of photorespiration and reduces photosynthetic efficiency. While plants have evolved numerous mechanisms to compensate for low CO2, the most effective are the carbon concentration mechanisms of C4, C2, and CAM photosynthesis; and the pumping of dissolved inorganic carbon, mainly by algae. C4 photosynthesis enables plants to dominate warm, dry and often salinized habitats, and to colonize areas that are too stressful for most plant groups. Because C4 lineages generally lack arborescence, they cannot form forests. Hence, where they predominate, C4 plants create a different landscape than would occur if C3 plants were to predominate. These landscapes (mostly grasslands and savannahs) present unique selection environments that promoted the diversification of animal guilds able to graze upon the C4 vegetation. Thus, the rise of C4 photosynthesis has made a significant contribution to the origin of numerous biomes in the modern biosphere.

  11. β-Diversity of functional groups of woody plants in a tropical dry forest in Yucatan.

    Directory of Open Access Journals (Sweden)

    Jorge Omar López-Martínez

    Full Text Available Two main theories have attempted to explain variation in plant species composition (β-diversity. Niche theory proposes that most of the variation is related to environment (environmental filtering, whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning, and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position, whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity -possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity

  12. β-Diversity of functional groups of woody plants in a tropical dry forest in Yucatan.

    Science.gov (United States)

    López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

    2013-01-01

    Two main theories have attempted to explain variation in plant species composition (β-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity -possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity patterns and

  13. Geographical patterns in the beta diversity of China's woody plants

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao

    2012-01-01

    with their environmental niches due to dispersal limitation induced by China’s topography and/or their low dispersal ability. The projected rapid climatic changes will likely endanger such species. Species dispersal processes should be taken into account in future conservation strategies in China.......Beta diversity (i.e. species turnover rate across space) is fundamental for understanding mechanisms controlling large-scale species richness patterns. However, the influences on beta diversity are still a matter of debate. In particular, the relative role of environmental and spatial processes (e.......g. environmental niche versus dispersal limitation of species) remains elusive, and the influence of species range size has been poorly tested. Here, using distribution maps of 11 405 woody species in China (ca 9.6 ¿ 106 km2), we investigated 1) the geographical and directional patterns of beta diversity for all...

  14. Contrasting land uses in Mediterranean agro-silvo-pastoral systems generated patchy diversity patterns of vascular plants and below-ground microorganisms.

    Science.gov (United States)

    Bagella, Simonetta; Filigheddu, Rossella; Caria, Maria Carmela; Girlanda, Mariangela; Roggero, Pier Paolo

    2014-12-01

    The aims of this paper were (i) to define how contrasting land uses affected plant biodiversity in Mediterranean agro-silvo-pastoral-systems across a gradient of disturbance regimes: cork oak forests, secondary grasslands, hay crops, grass covered vineyards, tilled vineyards; (ii) to determine whether these patterns mirrored those of below-ground microorganisms and whether the components of γ-diversity followed a similar model. The disturbance regimes affected plant assemblage composition. Species richness decreased with increasing land use intensity, the Shannon index showed the highest values in grasslands and hay crops. Plant assemblage composition patterns mirrored those of Basidiomycota and Ascomycota. Richness in Basidiomycota, denitrifying bacteria and microbial biomass showed the same trend as that observed for vascular plant richness. The Shannon index pattern of below-ground microorganisms was different from that of plants. The plant γ-diversity component model weakly mirrored those of Ascomycota. Patchy diversity patterns suggest that the maintenance of contrasting land uses associated with different productions typical of agro-silvo-pastoral-systems can guarantee the conservation of biodiversity.

  15. Volume, value and floristic diversity of Gabon's medicinal plant markets

    NARCIS (Netherlands)

    Towns, A.M.; Quiroz Villarreal, D.K.; Guinee, L.; Boer, H.; Andel, van T.

    2014-01-01

    Ethnopharmacological relevance - African medicinal plant markets offer insight into commercially important species, salient health concerns in the region, and possible conservation priorities. Still, little quantitative data is available on the trade in herbal medicine in Central Africa. The aim of

  16. Volume, value and floristic diversity of Gabon's medicinal plant markets

    NARCIS (Netherlands)

    Towns, A.M.; Quiroz Villarreal, D.K.; Guinee, L.; Boer, H.; Andel, van T.

    2014-01-01

    Ethnopharmacological relevance - African medicinal plant markets offer insight into commercially important species, salient health concerns in the region, and possible conservation priorities. Still, little quantitative data is available on the trade in herbal medicine in Central Africa. The aim of

  17. effect of bush burning on herbaceous plant diversity in lagos state ...

    African Journals Online (AJOL)

    conducted to assess the effect of bush burning on plant species diversity. Three frequently ... Data obtained for plants were compared using % frequency, % stand and Simpson and ... species are destroyed by fire and can become locally extinct if fire is too ..... unplanned fire in a semi-arid rangeland of South Africa. Journal ...

  18. Plant-associated microbiomes in arid lands: diversity, ecology and biotechnological potential

    KAUST Repository

    Soussi, Asma

    2015-08-28

    Background: Aridification is a worldwide serious threat directly affecting agriculture and crop production. In arid and desert areas, it has been found that microbial diversity is huge, built of microorganisms able to cope with the environmental harsh conditions by developing adaptation strategies. Plants growing in arid lands or regions facing prolonged abiotic stresses such as water limitation and salt accumulation have also developed specific physiological and molecular stress responses allowing them to thrive under normally unfavorable conditions. Scope: Under such extreme selection pressures, special root-associated bacterial assemblages, endowed with capabilities of plant growth promotion (PGP) and extremophile traits, are selected by the plants. In this review, we provide a general overview on the microbial diversity in arid lands and deserts versus specific microbial assemblages associated with plants. The ecological drivers that shape this diversity, how plant-associated microbiomes are selected, and their biotechnological potential are discussed. Conclusions: Selection and recruitment of the plant associated bacterial assemblages is mediated by the combination of the bio-pedo-agroclimatic conditions and the plant species or varieties. Diversity and functional redundancy of these associated PGPR makes them very active in supporting plant improvement, health and resistance to drought, salt and related stresses. Implementing proper biotechnological applications of the arid and desert-adapted PGPR constitute the challenge to be raised.

  19. Influence of plant species on population dynamics, genotypic diversity and antibiotic production by indigenous Pseudomonas spp

    NARCIS (Netherlands)

    Bergsma-Vlami, M.; Prins, M.E.; Raaijmakers, J.M.

    2005-01-01

    The population dynamics, genotypic diversity and activity of naturally-occurring 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. was investigated for four plant species (wheat, sugar beet, potato, lily) grown in two different soils. All four plant species tested, except lily and in some

  20. The relative importance of host-plant genetic diversity in structuring the associated herbivore community.

    Science.gov (United States)

    Tack, Ayco J M; Roslin, Tomas

    2011-08-01

    Recent studies suggest that intraspecific genetic diversity in one species may leave a substantial imprint on the surrounding community and ecosystem. Here, we test the hypothesis that genetic diversity within host-plant patches translates into consistent and ecologically important changes in the associated herbivore community. More specifically, we use potted, grafted oak saplings to construct 41 patches of four saplings each, with one, two, or four tree genotypes represented among the host plants. These patches were divided among two common gardens. Focusing first at the level of individual trees, we assess how tree-specific genotypic identity, patch-level genetic diversity, garden-level environmental variation, and their interactions affect the structure of the herbivore community. At the level of host-plant patches, we analyze whether the joint responses of herbivore species to environmental variation and genetic diversity result in differences in species diversity among tree quartets. Strikingly, both species-specific abundances and species diversity varied substantially among host-tree genotypes, among common gardens, and among specific locations within individual gardens. In contrast, the genetic diversity of the patch left a detectable imprint on local abundances of only two herbivore taxa. In both cases, the effect of genetic diversity was inconsistent among gardens and among host-plant genotypes. While the insect community differed significantly among individual host-plant genotypes, there were no interactive effects of the number of different genotypes within the patch. Overall, additive effects of intraspecific genetic diversity of the host plant explained a similar or lower proportion (7-10%) of variation in herbivore species diversity than did variation among common gardens. Combined with the few previous studies published to date, our study suggests that the impact of host-plant genetic diversity on the herbivore community can range from none to

  1. Growing knowledge: an overview of Seed Plant diversity in Brazil

    OpenAIRE

    Zappi, Daniela C.; Filardi,Fabiana L. Ranzato; Leitman,Paula; Souza, Vinícius C.; Bruno M. T. Walter; José R. Pirani; Morim,Marli P.; de Queiroz, Luciano P.; Cavalcanti,Taciana B.; Mansano, Vidal F.; Forzza,Rafaela C.; Abreu,Maria C.; Acevedo-Rodríguez, Pedro; Agra,Maria de F.; Almeida Jr.,Eduardo B.

    2016-01-01

    An updated inventory of Brazilian seed plants is presented and offers important insights into the country’s biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while th...

  2. Phyllosphere microbiology with special reference to diversity and plant genotype

    OpenAIRE

    Whipps, J. M.; Hand, Paul; Pink, David; Bending, G. D.

    2008-01-01

    The phyllosphere represents the habitat provided by the aboveground parts of plants, and on a global scale supports a large and complex microbial community. Microbial interactions in the phyllosphere can affect the fitness of plants in natural communities, the productivity of agricultural crops, and the safety of horticultural produce for human consumption. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonists, which is influenced by numero...

  3. Invasive stink bug favors naïve plants: Testing the role of plant geographic origin in diverse, managed environments.

    Science.gov (United States)

    Martinson, Holly M; Bergmann, Erik J; Venugopal, P Dilip; Riley, Christopher B; Shrewsbury, Paula M; Raupp, Michael J

    2016-01-01

    With the introduction and establishment of exotic species, most ecosystems now contain both native and exotic plants and herbivores. Recent research identifies several factors that govern how specialist herbivores switch host plants upon introduction. Predicting the feeding ecology and impacts of introduced generalist species, however, remains difficult. Here, we examine how plant geographic origin, an indicator of shared co-evolutionary history, influences patterns of host use by a generalist, invasive herbivore, while accounting for variation in plant availability. The brown marmorated stink bug, Halyomorpha halys, is a highly polyphagous Asian herbivore and an economically important invasive pest in North America and Europe. In visual surveys of 220 plant taxa in commercial nurseries in Maryland, USA, H. halys was more abundant on non-Asian plants and selected these over Asian plants. The relationship between the relative use of plants and their availability was strongly positive but depended also on plant origin at two of our three sites, where the higher relative use of non-Asian plants was greatest for highly abundant taxa. These results highlight the importance of considering both plant origin and relative abundance in understanding the selection of host plants by invasive generalist herbivores in diverse, natural and urban forests.

  4. Plant-hummingbird interactions in the West Indies: floral specialisation gradients associated with environment and hummingbird size.

    Science.gov (United States)

    Dalsgaard, Bo; Martín González, Ana M; Olesen, Jens M; Ollerton, Jeff; Timmermann, Allan; Andersen, Laila H; Tossas, Adrianne G

    2009-04-01

    Floral phenotype and pollination system of a plant may be influenced by the abiotic environment and the local pollinator assemblage. This was investigated in seven plant-hummingbird assemblages on the West Indian islands of Grenada, Dominica and Puerto Rico. We report all hummingbird and insect pollinators of 49 hummingbird-pollinated plant species, as well as six quantitative and semi-quantitative floral characters that determine visitor restriction, attraction and reward. Using nonmetric multidimensional scaling analysis, we show that hummingbird-pollinated plants in the West Indies separate in floral phenotypic space into two gradients-one associated with the abiotic environment and another with hummingbird size. Plants pollinated by large, long-billed hummingbirds had flowers with long corolla tube, large amounts of nectar and showy orange-red colouration. These attracted few or no insect species, whereas plants pollinated by small, short-billed hummingbirds were frequently pollinated by insects, particularly lepidopterans. The separation of plants related to environmental factors showed that species in the wet and cold highlands produced large amounts of dilute nectar, possessed no or a weak odour, and were associated with few insects, particularly few hymenopterans, compared to plants in the dry and warm lowlands. The most specialised hummingbird-pollinated plants are found in the West Indian highlands where they are pollinated by mainly large, long-billed hummingbirds. At the other extreme, highly generalised plants growing in the dry and warm lowlands are pollinated by small, short-billed hummingbirds and numerous insect species. This illustrates that, even within the hummingbird-pollinated flora, pollination syndrome and the degree of specialisation may vary tremendously depending on pollinator morphology and environment.

  5. Plant Glutathione Biosynthesis: Diversity in Biochemical Regulation and Reaction Products

    Directory of Open Access Journals (Sweden)

    Ashley eGalant

    2011-09-01

    Full Text Available In plants, exposure to temperature extremes, heavy metal-contaminated soils, drought, air pollutants, and pathogens results in the generation of reactive oxygen species that alter the intracellular redox environment, which in turn influences signaling pathways and cell fate. As part of their response to these stresses, plants produce glutathione. Glutathione acts as an antioxidant by quenching reactive oxygen species, and is involved in the ascorbate-glutathione cycle that eliminates damaging peroxides. Plants also use glutathione for the detoxification of xenobiotics, herbicides, air pollutants (sulfur dioxide and ozone, and toxic heavy metals. Two enzymes catalyze glutathione synthesis: glutamate-cysteine ligase (GCL, and glutathione synthetase (GS. Glutathione is a ubiquitous protective compound in plants, but the structural and functional details of the proteins that synthesize it, as well as the potential biochemical mechanisms of their regulation, have only begun to be explored. As discussed here, the core reactions of glutathione synthesis are conserved across various organisms, but plants have diversified both the regulatory mechanisms that control its synthesis and the range of products derived from this pathway. Understanding the molecular basis of glutathione biosynthesis and its regulation will expand our knowledge of this component in the plant stress response network.

  6. Plant glutathione biosynthesis: diversity in biochemical regulation and reaction products.

    Science.gov (United States)

    Galant, Ashley; Preuss, Mary L; Cameron, Jeffrey C; Jez, Joseph M

    2011-01-01

    In plants, exposure to temperature extremes, heavy metal-contaminated soils, drought, air pollutants, and pathogens results in the generation of reactive oxygen species that alter the intracellular redox environment, which in turn influences signaling pathways and cell fate. As part of their response to these stresses, plants produce glutathione. Glutathione acts as an anti-oxidant by quenching reactive oxygen species, and is involved in the ascorbate-glutathione cycle that eliminates damaging peroxides. Plants also use glutathione for the detoxification of xenobiotics, herbicides, air pollutants (sulfur dioxide and ozone), and toxic heavy metals. Two enzymes catalyze glutathione synthesis: glutamate-cysteine ligase, and glutathione synthetase. Glutathione is a ubiquitous protective compound in plants, but the structural and functional details of the proteins that synthesize it, as well as the potential biochemical mechanisms of their regulation, have only begun to be explored. As discussed here, the core reactions of glutathione synthesis are conserved across various organisms, but plants have diversified both the regulatory mechanisms that control its synthesis and the range of products derived from this pathway. Understanding the molecular basis of glutathione biosynthesis and its regulation will expand our knowledge of this component in the plant stress response network.

  7. [FeFe]-Hydrogenase Abundance and Diversity along a Vertical Redox Gradient in Great Salt Lake, USA

    Directory of Open Access Journals (Sweden)

    Eric S. Boyd

    2014-11-01

    Full Text Available The use of [FeFe]-hydrogenase enzymes for the biotechnological production of H2 or other reduced products has been limited by their sensitivity to oxygen (O2. Here, we apply a PCR-directed approach to determine the distribution, abundance, and diversity of hydA gene fragments along co-varying salinity and O2 gradients in a vertical water column of Great Salt Lake (GSL, UT. The distribution of hydA was constrained to water column transects that had high salt and relatively low O2 concentrations. Recovered HydA deduced amino acid sequences were enriched in hydrophilic amino acids relative to HydA from less saline environments. In addition, they harbored interesting variations in the amino acid environment of the complex H-cluster metalloenzyme active site and putative gas transfer channels that may be important for both H2 transfer and O2 susceptibility. A phylogenetic framework was created to infer the accessory cluster composition and quaternary structure of recovered HydA protein sequences based on phylogenetic relationships and the gene contexts of known complete HydA sequences. Numerous recovered HydA are predicted to harbor multiple N- and C-terminal accessory iron-sulfur cluster binding domains and are likely to exist as multisubunit complexes. This study indicates an important role for [FeFe]-hydrogenases in the functioning of the GSL ecosystem and provides new target genes and variants for use in identifying O2 tolerant enzymes for biotechnological applications.

  8. Effect of plantations on plant species diversity in the Darabkola, Mazandaran Province, North of Iran

    Directory of Open Access Journals (Sweden)

    HASSAN POURBABAEI

    2012-04-01

    Full Text Available Pourbabaei H, Asgari F, Reif A, Abedi R. 2012. Effect of plantations on plant species diversity in the Darabkola, Mazandaran Province, North of Iran. Biodiversitas 13: 72-78. In this study, the effect of plantations on plant species diversity was investigated in Darabkola, Mazandaran province, north of Iran. To conduct the study, a natural mixed forest, a broad–leaved plantation (Alnus subcordata-Acer velutinum and a coniferous plantation (Cupressus sempervirens var. horizontalis-Pinus brutia were selected. 35 sampling plots were taken in systematic random method in each area. Data analysis was carried out using Simpson, Hill's N2, Shannon-Wiener and Mc Arthur's N1 diversity indices, Smith and Wilson evenness index and species richness. Results revealed that there were 32 plant species in natural forest and 30 plant species were found in each plantation. Rosaceae and Lamiaceae were the main families in the studied areas. Diversity and evenness indices of all vegetation layers had the most values in the natural forest. Richness of woody plants had the highest value in the natural forest, while herbaceous richness was the highest in coniferous plantation. Mc Arthur's N1 had the highest value among diversity indices and followed by Hill's N2, Shannon-Wiener and Simpson indices, respectively. In addition, results showed that there were significant differences among diversity, evenness and richness indices in all vegetation layers in the three studied areas.

  9. Potential benefits of plant diversity on vegetated roofs: a literature review.

    Science.gov (United States)

    Cook-Patton, Susan C; Bauerle, Taryn L

    2012-09-15

    Although vegetated green roofs can be difficult to establish and maintain, they are an increasingly popular method for mitigating the negative environmental impacts of urbanization. Most green roof development has focused on maximizing green roof performance by planting one or a few drought-tolerant species. We present an alternative approach, which recognizes green roofs as dynamic ecosystems and employs a diversity of species. We draw links between the ecological and green roof literature to generate testable predictions about how increasing plant diversity could improve short- and long-term green roof functioning. Although we found few papers that experimentally manipulated diversity on green roofs, those that did revealed ecological dynamics similar to those in more natural systems. However, there are many unresolved issues. To improve overall green roof performance, we should (1) elucidate the links among plant diversity, structural complexity, and green roof performance, (2) describe feedback mechanisms between plant and animal diversity on green roofs, (3) identify species with complementary traits, and (4) determine whether diverse green roof communities are more resilient to disturbance and environmental change than less diverse green roofs.

  10. Evolutionary relationships and functional diversity of plant sulfate transporters

    Directory of Open Access Journals (Sweden)

    Hideki eTakahashi

    2012-01-01

    Full Text Available Sulfate is an essential nutrient cycled in nature. Ion transporters that specifically facilitate the transport of sulfate across the membranes are found ubiquitously in living organisms. The phylogenetic analysis of known sulfate transporters and their homologous proteins from eukaryotic organisms indicate two evolutionarily distinct groups of sulfate transport systems. One major group named Tribe 1 represents yeast and fungal SUL, plant SULTR and animal SLC26 families. The evolutionary origin of SULTR family members in land plants and green algae is suggested to be common with yeast and fungal sulfate transporters (SUL and animal anion exchangers (SLC26. The lineage of plant SULTR family is expanded into four subfamilies (SULTR1 to SULTR4 in land plant species. By contrast, the putative SULTR homologues from Chlorophyte green algae are in two separate lineages; one with the subfamily of plant tonoplast-localized sulfate transporters (SULTR4, and the other diverged before the appearance of lineages for SUL, SULTR and SLC26. There also was a group of yet undefined members of putative sulfate transporters in yeast and fungi divergent from these major lineages in Tribe 1. The other distinct group is Tribe 2, primarily composed of animal sodium-dependent sulfate/carboxylate transporters (SLC13 and plant tonoplast-localized dicarboxylate transporters (TDT. The putative sulfur-sensing protein (SAC1 and SAC1-like transporters (SLT of Chlorophyte green algae, bryophyte and lycophyte show low degrees of sequence similarities with SLC13 and TDT. However, the phylogenetic relationship between SAC1/SLT and the other two families, SLC13 and TDT in Tribe 2, is not clearly supported. In addition, the SAC1/SLT family is completely absent in the angiosperm species analyzed. The present study suggests distinct evolutionary trajectories of sulfate transport systems for land plants and green algae.

  11. Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the im-portance of species composition, species richness, the type of different growth forms, and plant bio-mass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, her-baceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a de-crease from 13196.96±719.69 g/m2 in the sedge-dominated K. tibetica swamp to 2869.58±147.52 g/m2 in the forb and sedge dominated K. pygmaea meadow, and to 2153.08±141.95 g/m2 in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of below-ground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P<0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P<0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P<0.05); belowground biomass was positively correlated with soil moisture (P<0.05). However, in the K

  12. Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the importance of species composition, species richness, the type of different growth forms, and plant biomass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, herbaceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a decrease from 13196.96±719.69 g/m2 in the sedge-dominated K. tibetica swamp to 2869.58±147.52 g/m2 in the forb and sedge dominated K. pygmaea meadow, and to 2153.08±141.95 g/m2 in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of belowground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P<0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P<0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P<0.05); belowground biomass was positively correlated with soil moisture (P<0.05). However, in

  13. Plant species richness and productivity determine the diversity of soil fungal guilds in temperate coniferous forest and bog habitats.

    Science.gov (United States)

    Hiiesalu, Indrek; Bahram, Mohammad; Tedersoo, Leho

    2017-09-01

    Fungi have important roles as decomposers, mycorrhizal root symbionts and pathogens in forest ecosystems, but there is limited information about their diversity and composition at the landscape scale. This work aimed to disentangle the factors underlying fungal richness and composition along the landscape-scale moisture, organic matter and productivity gradients. Using high-throughput sequencing, we identified soil fungi from 54 low-productivity Pinus sylvestris-dominated plots across three study areas in Estonia and determined the main predictors of fungal richness based on edaphic, floristic and spatial variables. Fungal richness displayed unimodal relationship with organic matter and deduced soil moisture. Plant richness and productivity constituted the key predictors for taxonomic richness of functional guilds. Composition of fungi and the main ectomycorrhizal fungal lineages and hyphal exploration types was segregated by moisture availability and soil nitrogen. We conclude that plant productivity and diversity determine the richness and proportion of most functional groups of soil fungi in low-productive pine forests on a landscape scale. Adjacent stands of pine forest may differ greatly in the dominance of functional guilds that have marked effects on soil carbon and nitrogen cycling in these forest ecosystems. © 2017 John Wiley & Sons Ltd.

  14. Soil fertility increases with plant species diversity in a long-term biodiversity experiment.

    Science.gov (United States)

    Dybzinski, Ray; Fargione, Joseph E; Zak, Donald R; Fornara, Dario; Tilman, David

    2008-11-01

    Most explanations for the positive effect of plant species diversity on productivity have focused on the efficiency of resource use, implicitly assuming that resource supply is constant. To test this assumption, we grew seedlings of Echinacea purpurea in soil collected beneath 10-year-old, experimental plant communities containing one, two, four, eight, or 16 native grassland species. The results of this greenhouse bioassay challenge the assumption of constant resource supply; we found that bioassay seedlings grown in soil collected from experimental communities containing 16 plant species produced 70% more biomass than seedlings grown in soil collected beneath monocultures. This increase was likely attributable to greater soil N availability, which had increased in higher diversity communities over the 10-year-duration of the experiment. In a distinction akin to the selection/complementarity partition commonly made in studies of diversity and productivity, we further determined whether the additive effects of functional groups or the interactive effects of functional groups explained the increase in fertility with diversity. The increase in bioassay seedling biomass with diversity was largely explained by a concomitant increase in N-fixer, C4 grass, forb, and C3 grass biomass with diversity, suggesting that the additive effects of these four functional groups at higher diversity contributed to enhance N availability and retention. Nevertheless, diversity still explained a significant amount of the residual variation in bioassay seedling biomass after functional group biomass was included in a multiple regression, suggesting that interactions also increased fertility in diverse communities. Our results suggest a mechanism, the fertility effect, by which increased plant species diversity may increase community productivity over time by increasing the supply of nutrients via both greater inputs and greater retention.

  15. Effects of resource competition and herbivory on plant performance along a natural productivity gradient

    NARCIS (Netherlands)

    Van Der Wal, R; Egas, M; Bakker, J; van der Veen, A.

    2000-01-01

    1 The effects of resource competition and herbivory on a target species, Triglochin maritima, were studied along a productivity gradient of vegetation biomass in a temperate salt marsh. 2 Transplants were used to measure the impact of grazing, competition and soil fertility over two growing seasons.

  16. Diversity of heterotrimeric G-protein γ subunits in plants

    Directory of Open Access Journals (Sweden)

    Trusov Yuri

    2012-10-01

    Full Text Available Abstract Background Heterotrimeric G-proteins, consisting of three subunits Gα, Gβ and Gγ are present in most eukaryotes and mediate signaling in numerous biological processes. In plants, Gγ subunits were shown to provide functional selectivity to G-proteins. Three unconventional Gγ subunits were recently reported in Arabidopsis, rice and soybean but no structural analysis has been reported so far. Their relationship with conventional Gγ subunits and taxonomical distribution has not been yet demonstrated. Results After an extensive similarity search through plant genomes, transcriptomes and proteomes we assembled over 200 non-redundant proteins related to the known Gγ subunits. Structural analysis of these sequences revealed that most of them lack the obligatory C-terminal prenylation motif (CaaX. According to their C-terminal structures we classified the plant Gγ subunits into three distinct types. Type A consists of Gγ subunits with a putative prenylation motif. Type B subunits lack a prenylation motif and do not have any cysteine residues in the C-terminal region, while type C subunits contain an extended C-terminal domain highly enriched with cysteines. Comparative analysis of C-terminal domains of the proteins, intron-exon arrangement of the corresponding genes and phylogenetic studies suggested a common origin of all plant Gγ subunits. Conclusion Phylogenetic analyses suggest that types C and B most probably originated independently from type A ancestors. We speculate on a potential mechanism used by those Gγ subunits lacking isoprenylation motifs to anchor the Gβγ dimer to the plasma membrane and propose a new flexible nomenclature for plant Gγ subunits. Finally, in the light of our new classification, we give a word of caution about the interpretation of Gγ research in Arabidopsis and its generalization to other plant species.

  17. Plant diversity effects on ecosystem evapotranspiration and carbon uptake: a controlled environment (Ecotron) and modeling approach

    Science.gov (United States)

    Milcu, Alexandru; Roy, Jacques

    2016-04-01

    Effects of species and functional diversity of plants on ecosystem evapotranspiration and carbon fluxes have been rarely assessed simultaneously. Here we present the results from an experiment that combined a lysimeter setup in a controlled environment facility (Ecotron) with large ecosystem samples/ monoliths originating from a long-term biodiversity experiment ("The Jena Experiment") and a modelling approach. We aimed at (1) quantifying the impact of plant species richness (4 vs. 16 species) on day- and night-time ecosystem water vapor fluxes and carbon uptake, (2) partitioning ecosystem evapotranspiration into evaporation and plant transpiration using the Shuttleworth and Wallace (SW) energy partitioning model, and (3) identifying the most parsimonious predictors of water vapor vapor and CO2 fluxes using plant functional trait-based metrics such as functional diversity and community weighted means. The SW model indicated that at low plant species richness, a higher proportion of the available energy was diverted to evaporation (a non-productive flux), while at higher species richness the proportion of ecosystem transpiration (a production-related water flux) increased. This led to an increased carbon gain per amount of water vapor loss (i.e. increased water use efficiency). While the LAI controlled the carbon and water fluxes, we also found that the diversity of plant functional traits, and in particular of leaf nitrogen concentration are potential important predictors of ecosystem transpiration and carbon uptake and consequently significantly contributed to increase in water use efficiency in communities with higher plant diversity.

  18. Moderate land use changes plant functional composition without loss of functional diversity in India's Western Ghats.

    Science.gov (United States)

    Mandle, Lisa; Ticktin, Tamara

    2015-09-01

    The fields of ecology and conservation science increasingly recognize the importance of managing for functional composition and functional diversity to maintain critical ecosystem processes and services. However, little is known about the degree to which widespread but moderate forms of land use that maintain overall vegetation structure are compatible with the conservation of functional diversity. We assessed differences in plani functional composition and functional diversity across savanna woodlands in the Western Ghats, India, managed with varying degrees of biomass extraction, livestock grazing, and ground fire. Across the gradient of moderate land uses, we found shifts in functional composition but no overall decline in functional diversity with land, use intensification. Biomass extraction was associated with changes in dispersal mode, reduced seed mass, and lower overstory functional diversity. Livestock grazing was associated with shorter overstory species, reduced seed mass, and increased understory functional diversity. Nonnative invasive species contributed to shifts in understory functional composition with livestock grazing and increased functional diversity with more intensive land use. Our study highlights both the utility and some limitations of assessing conservation value with functional diversity. These results suggest that moderate-intensity local land use can be compatible with maintenance of functional diversity in savanna woodlands of the Western Ghats, and further efforts to maximize this compatibility would benefit conservation in South India's extensive human-managed landscapes. However, using functional diversity as the sole metric by which to gauge conservation value can mask threats from invasive species and loss of diversity within categories of biotic dispersal. Therefore, functional diversity metrics are likely to provide a valuable complement to, but not replacement for, other management targets such as species composition.

  19. Diverse Roles of ERECTA Family Genes in Plant Development

    Institute of Scientific and Technical Information of China (English)

    Elena D.Shpak

    2013-01-01

    Multiple receptor-like kinases (RLKs) enable intercellular communication that coordinates growth and development of plant tissues. ERECTA family receptors (ERfs) are an ancient family of leucine-rich repeat RLKs that in Arabidopsis consists of three genes: ERECTA, ERL1, and ERL2. ERfs sense secreted cysteine-rich peptides from the EPF/EPFL family and transmit the signal through a MAP kinase cascade. This review discusses the functions of ERfs in stomata development, in regulation of longitudinal growth of aboveground organs, during reproductive development, and in the shoot apical meristem. In addition the role of ERECTA in plant responses to biotic and abiotic factors is examined.

  20. [Agrobacterium rubi strains from blueberry plants are highly diverse].

    Science.gov (United States)

    Abrahamovich, Eliana; López, Ana C; Alippi, Adriana M

    2014-01-01

    The diversity of a collection of Agrobacterium rubi strains isolated from blueberries from different regions of Argentina was studied by conventional microbiological tests and molecular techniques. Results from biochemical and physiological reactions, as well as from rep-PCR and RFLP analysis of PCR-amplified 23S rDNA showed high phenotypic and genotypic intraspecific variation. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

  1. Effects of plant diversity on microbial nitrogen and phosphorus dynamics in soil

    Science.gov (United States)

    Prommer, Judith; Braun, Judith; Daly, Amanda; Gorka, Stefan; Hu, Yuntao; Kaiser, Christina; Martin, Victoria; Meyerhofer, Werner; Walker, Tom W. N.; Wanek, Wolfgang; Wasner, Daniel; Wiesenbauer, Julia; Zezula, David; Zheng, Qing; Richter, Andreas

    2017-04-01

    There is a general consensus that plant diversity affects many ecosystem functions. One example of such an effect is the enhanced aboveground and belowground plant biomass production with increasing species richness, with implications for carbon and nutrient distribution in soil. The Jena Experiment (http://www.the-jena-experiment.de/), a grassland biodiversity experiment established in 2002 in Germany, comprises different levels of plant species richness and different numbers of plant functional groups. It provides the opportunity to examine how changes in biodiversity impact on microbially-mediated nutrient cycling processes. We here report on plant diversity and plant functional composition effects on growth and nitrogen and phosphorus transformation rates, including nitrogen use efficiency, of microbial communities. Microbial growth rates and microbial biomass were positively affected by increasing plant species richness. Amino acid and ammonium concentrations in soil were also positively affected by plant species richness, while phosphate concentrations in contrast were negatively affected. The cycling of organic N in soils (estimated as gross protein depolymerization rates) increased about threefold with plant diversity, while gross N and P mineralization were not significantly affected by either species or functional richness. Microbial nitrogen use efficiency did not respond to different levels of plant diversity but was very high (0.96 and 0.98) across all levels of plant species richness, demonstrating a low N availability for microbes. Taken together this indicates that soil microbial communities were able to meet the well-documented increase in plant N content with species richness, and also the higher N demand of the microbial community by increasing the recycling of organic N such as proteins. In fact, the microbial community even overcompensated the increased plant and microbial N demand, as evidenced by increased levels of free amino acids and

  2. Floristic diversity and regeneration status of woody plants in Zengena Forest, a remnant montane forest patch in northwestern Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Desalegn Tadele; Ermias Lulekal; Destaw Damtie; Adane Assefa

    2014-01-01

    The study was conducted at Zengena forest, a fragmented remnant montane forest in northwestern Ethiopia, which surrounds Lake Zengena. The purpose was to assess the species composition, diversity and the regeneration status of woody plants. A total of 27 plots of 20 m × 20 m were sampled along the line transects laid down the altitudinal gradient from the edge of the forest encompassing the lake to the edge of the lake in eight aspects. In each plot, woody species were counted and the diameter at breast height and the height of trees and shrubs were measured. A total of 50 woody species belonging to 31 families were found, of which 17 (34%) were trees, 7 (14%) trees or shrubs, 23 (46%) shrubs and 3 (6%) lianas. The overall Shannon-Wiener diversity and evenness indices of woody species were 2.74 and 0.7, respectively. Clausena anisata had the highest relative density (23.5%), Rapanea rhododendroides the highest relative frequency (6.5%) and Prunus afri-cana the highest relative dominance (45%) and importance value index (IVI, 51.6). The total basal area and density of woody plants were 22.3 m2⋅ha-1 and 2,202 individuals⋅ha-1, respectively. The population structure showed variations among woody plants and revealed varied regeneration patterns of different species. The importance value index and population structure revealed that some species are threatened and need prioritiza-tion for conservation measures. The results suggest that remnant forest patches in the highlands of northern Ethiopia host several woody plant species that are almost disappearing in other areas due to deforestation.

  3. Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots

    Science.gov (United States)

    Picard, Christine; Bosco, Marco

    2008-01-01

    Several soil microorganisms colonizing roots are known to naturally promote the health of plants by controlling a range of plant pathogens, including bacteria, fungi, and nematodes. The use of theses antagonistic microorganisms, recently named plant-probiotics, to control plant-pathogenic fungi is receiving increasing attention, as they may represent a sustainable alternative to chemical pesticides. Many years of research on plant-probiotic microorganisms (PPM) have indicated that fluorescent pseudomonads producing antimicrobial compounds are largely involved in the suppression of the most widespread soilborne pathogens. Phenotype and genotype analysis of plant-probiotic fluorescent pseudomonads (PFP) have shown considerable genetic variation among these types of strains. Such variability plays an important role in the rhizosphere competence and the biocontrol ability of PFP strains. Understanding the mechanisms by which genotypic and phenotypic diversity occurs in natural populations of PFP could be exploited to choose those agricultural practices which best exploit the indigenous PFP populations, or to isolate new plant-probiotic strains for using them as inoculants. A number of different methods have been used to study diversity within PFP populations. Because different resolutions of the existing microbial diversity can be revealed depending on the approach used, this review first describes the most important methods used for the assessment of fluorescent Pseudomonas diversity. Then, we focus on recent data relating how differences in genotypic and phenotypic diversity within PFP communities can be attributed to geographic location, climate, soil type, soil management regime, and interactions with other soil microorganisms and host plants. It becomes evident that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PFP populations.

  4. Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2017-02-01

    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity.

  5. Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders.

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2017-02-23

    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity.

  6. Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders

    Science.gov (United States)

    Ordonez, Alejandro; Svenning, Jens-Christian

    2017-01-01

    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity. PMID:28230069

  7. Assessment of Genetic Diversity in Seed Plants Based on a Uniform π Criterion

    Directory of Open Access Journals (Sweden)

    Bin Ai

    2014-12-01

    Full Text Available Despite substantial advances in genotyping techniques and massively accumulated data over the past half century, a uniform measurement of neutral genetic diversity derived by different molecular markers across a wide taxonomical range has not yet been formulated. We collected genetic diversity data on seed plants derived by AFLP, allozyme, ISSR, RAPD, SSR and nucleotide sequences, converted expected heterozygosity (He to nucleotide diversity (π, and reassessed the relationship between plant genetic diversity and life history traits or extinction risk. We successfully established a uniform π criterion and developed a comprehensive plant genetic diversity database. The mean population-level and species-level π values across seed plants were 0.00374 (966 taxa, 155 families, 47 orders and 0.00569 (728 taxa, 130 families, 46 orders, respectively. Significant differences were recovered for breeding system (p < 0.001 at the population level and geographic range (p = 0.023 at the species level. Selfing taxa had significantly lower π values than outcrossing and mixed-mating taxa, whereas narrowly distributed taxa had significantly lower π values than widely distributed taxa. Despite significant differences between the two extreme threat categories (critically endangered and least concern, the genetic diversity reduction on the way to extinction was difficult to detect in early stages.

  8. The potential of plant viruses to promote genotypic diversity via genotype x environment interactions

    DEFF Research Database (Denmark)

    van Mölken, Tamara; Stuefer, Josef F.

    2011-01-01

    † Background and Aims Genotype by environment (G × E) interactions are important for the long-term persistence of plant species in heterogeneous environments. It has often been suggested that disease is a key factor for the maintenance of genotypic diversity in plant populations. However, empirical...... evidence for this contention is scarce. Here virus infection is proposed as a possible candidate for maintaining genotypic diversity in their host plants. † Methods The effects of White clover mosaic virus (WClMV) on the performance and development of different Trifolium repens genotypes were analysed...... and the G × E interactions were examined with respect to genotypespecific plant responses to WClMV infection. Thus, the environment is defined as the presence or absence of the virus. † Key Results WClMV had a negative effect on plant performance as shown by a decrease in biomass and number of ramets...

  9. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    Science.gov (United States)

    Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

    2013-10-01

    Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 μg N2O m-2 d-1, and improved nitrate removal (P 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

  10. Economic valuation of plant diversity storage service provided by Brazilian rupestrian grassland ecosystems.

    Science.gov (United States)

    Resende, F M; Fernandes, G W; Coelho, M S

    2013-11-01

    The rupestrian grassland ecosystems provide various goods and services to society and support a significant amount of biological diversity. Notably the rich plant diversity has high levels of endemism and a variety of uses among the local communities and general society. Despite the socio-ecological importance of these ecosystems, they are subjected to significant anthropogenic pressures. The goal of this study is to perform economic valuation of the plant diversity storage service provided by rupestrian grassland ecosystems to provide grounds for the development of conservation policies and encourage sustainable practices in these ecosystems. Given the intense human disturbances and unique flora, the Serra do Cipó (southern portion of the Espinhaço Range in southeast Brazil) was selected for the study. We estimate the monetary value related to the plant diversity storage service provided by the study area using the maintenance costs of native plants in the living collections of the botanical garden managed by the Zoobotanical Foundation - Belo Horizonte (located 97 km from Serra do Cipó). The plant diversity storage value provided by Serra do Cipó ecosystems is significant, reaching US$25.26 million year-1. This study contributes to the development of perspectives related to the conservation of rupestrian grassland ecosystems as well as others threatened tropical ecosystems with high biodiversity.

  11. Comparison of fractal characteristics of species richness patterns among different plant taxonomic groups along an altitudinal gradient

    Institute of Scientific and Technical Information of China (English)

    REN Haibao; ZHANG Linyan; MA Keping

    2007-01-01

    This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees,shrubs,herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations.Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing,China.Both transects were continuous and 2 m wide,and every individual tree and shrub was recorded in each of them.Discrete quadrats of 1m × 1m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients.The level interval between the quadrats was 10m and 25m respectively.In this study,transects A and B were combined into one transect AB,and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns.Species richness in each quadrat was calculated using a program written in Matlab 6.0.Direct gradient analysis was used to describe the overall trends in the species richness of trees,shrubs,herbs and other plants with change in altitude,while the non-brown ffactal model was used to detect more accurately their variations at various scales along the gradient.The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function.Generally,ecological phenomena are determined not by a single ecological process but by multiple ones.These processes act on ecological patterns within their own spatial scales.In the non-brown fractal model,the spatial random functions are nested within a larger range of spatial scales.The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero.In this paper,we reached the following results and conclusions

  12. Decoupling factors affecting plant diversity and cover on extensive green roofs.

    Science.gov (United States)

    MacIvor, J Scott; Margolis, Liat; Puncher, Curtis L; Carver Matthews, Benjamin J

    2013-11-30

    Supplemental irrigation systems are often specified on green roofs to ensure plant cover and growth, both important components of green roof performance and aesthetics. Properties of the growing media environment too can alter the assemblage of plant species able to thrive. In this study we determine how plant cover, above ground biomass and species diversity are influenced by irrigation and growing media. Grass and forb vegetative cover and biomass were significantly greater in organic based growing media but there was no effect of supplemental irrigation, with two warm season grasses dominating in those treatments receiving no supplemental irrigation. On the other hand, plant diversity declined without irrigation in organic media, and having no irrigation in inorganic growing media resulted in almost a complete loss of cover. Sedum biomass was less in inorganic growing media treatments and species dominance shifted when growing media organic content increased. Our results demonstrate that supplemental irrigation is required to maintain plant diversity on an extensive green roof, but not necessarily plant cover or biomass. These results provide evidence that planting extensive green roofs with a mix of plant species can ensure the survival of some species; maintaining cover and biomass when supplemental irrigation is turned off to conserve water, or during extreme drought.

  13. Plant microbial diversity is suggested as the key to future biocontrol and health trends.

    Science.gov (United States)

    Berg, Gabriele; Köberl, Martina; Rybakova, Daria; Müller, Henry; Grosch, Rita; Smalla, Kornelia

    2017-05-01

    The microbiome of plants plays a crucial role in both plant and ecosystem health. Rapid advances in multi-omics tools are dramatically increasing access to the plant microbiome and consequently to the identification of its links with diseases and to the control of those diseases. Recent insights reveal a close, often symbiotic relationship between microorganisms and plants. Microorganisms can stimulate germination and plant growth, prevent diseases, and promote stress resistance and general fitness. Plants and their associated microorganisms form a holobiont and have to be considered as co-evolved species assemblages consisting of bacterial, archaeal and diverse eukaryotic species. The beneficial interplay of the host and its microbiome is responsible for maintaining the health of the holobiont, while diseases are often correlated with microbial dysbioses. Microbial diversity was identified as a key factor in preventing diseases and can be implemented as a biomarker in plant protection strategies. Targeted and predictive biocontrol approaches are possible by developing microbiome-based solutions. Moreover, combined breeding and biocontrol strategies maintaining diversity and ecosystem health are required. The analysis of plant microbiome data has brought about a paradigm shift in our understanding of its role in health and disease and has substantial consequences for biocontrol and health issues. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Biogeographical diversity of plant associated microbes in arcto-alpine plants

    NARCIS (Netherlands)

    Kumar, Manoj Gopala Krishnan

    2016-01-01

    Terrestrial plants and microbes have co-evolved since the emergence of the former on Earth. Associations with microorganisms can be either beneficial or detrimental for plants. Microbes can be found in the soil surrounding the plant roots, but also in all plant tissues, including seeds. In arcto-alp

  15. Variation in plant defenses of Didymopanax vinosum (Cham. & Schltdl. Seem. (Apiaceae across a vegetation gradient in a Brazilian cerrado

    Directory of Open Access Journals (Sweden)

    Pais Mara Patrícia

    2003-01-01

    Full Text Available Cerrado vegetation is composed of a mosaic of vegetation types, from campo sujo, dominated by herbs; campo cerrado and cerrado sensu stricto, with shrubby vegetation; to cerradão, with trees forming a denser forest. This physiognomic mosaic is related to differences in the water availability in the soil. Cerrado plants are considered physically and chemically well defended against herbivores, but there are no studies showing how plants allocate investment to various types of defensive mechanisms in different habitat physiognomies. The defensive mechanisms and the nutritional traits of a cerrado plant, Didymopanax vinosum (Cham. & Schltdl. Seem. (Apiaceae, were compared along a vegetation gradient. Toughness, as well as water, nitrogen, cellulose, lignin, and tannin contents were measured in young and mature leaves of D. vinosum collected in campo cerrado, cerrado sensu stricto (s.s. and cerradão. Plants from cerrado s.s. and cerradão were of better nutritional quality but also had higher tannin contents than campo cerrado plants. Some type of compensation mechanism could have been selected to provide an optimum investment in defense, according to limitations imposed by water deficits in the habitat.

  16. Plant and Microbial Dynamics Along Gradients in Soil Texture and Eolian Dust Accumulation in the Colorado Plateau.

    Science.gov (United States)

    Neff, J. C.; Reynolds, R.; Lamothe, P.; Belnap, J.

    2001-12-01

    The canyonlands region of Southwest Utah is made up of soils with a range of textures and chemistries. We have identified three transects of soils that range from high sand to high silt content in order to examine the effect of soil texture and chemistry on plant and microbial dynamics. We also take advantage of new techniques that allow separation of eolian-derived fine soil particles from in situ weathering and erosion products to evaluate the role that dust deposition plays in the chemistry of desert ecosystems. We present results from several studies along these transects including measurements of hydrologic fluxes and comparisons of soil and plant chemistry. We have also carried out experiments on microbial and plant processes along gradients with the aim of linking biological dynamics to variation in surficial chemistry and hydrology. Our initial results indicate that water holding capacity is substantially higher in silts vs. sandy soils but that increases in water availability in sands have a disproportionate effect on soil respiration rates with a more rapid and prolonged response to wetting in sands vs. silts. Comparisons of plant and soil chemistry suggest that plants and soils show similar increases in Mg and Mn concentrations along our textural transects. In addition, native bunch grasses growing in high eolian silt environments show elevated P content in their tissues and may reflect the input of P in eolian deposition. With these studies, we are beginning to build a mechanistic framework for understanding the relationship between eolian deposition and ecosystem response in arid environments.

  17. Plant functional diversity increases grassland productivity-related water vapor fluxes: an Ecotron and modeling approach.

    Science.gov (United States)

    Milcu, Alexandru; Eugster, Werner; Bachmann, Dörte; Guderle, Marcus; Roscher, Christiane; Gockele, Annette; Landais, Damien; Ravel, Olivier; Gessler, Arthur; Lange, Markus; Ebeling, Anne; Weisser, Wolfgang W; Roy, Jacques; Hildebrandt, Anke; Buchmann, Nina

    2016-08-01

    The impact of species richness and functional diversity of plants on ecosystem water vapor fluxes has been little investigated. To address this knowledge gap, we combined a lysimeter setup in a controlled environment facility (Ecotron) with large ecosystem samples/monoliths originating from a long-term biodiversity experiment (The Jena Experiment) and a modeling approach. Our goals were (1) quantifying the impact of plant species richness (four vs. 16 species) on day- and nighttime ecosystem water vapor fluxes; (2) partitioning ecosystem evapotranspiration into evaporation and plant transpiration using the Shuttleworth and Wallace (SW) energy partitioning model; and (3) identifying the most parsimonious predictors of water vapor fluxes using plant functional-trait-based metrics such as functional diversity and community weighted means. Daytime measured and modeled evapotranspiration were significantly higher in the higher plant diversity treatment, suggesting increased water acquisition. The SW model suggests that, at low plant species richness, a higher proportion of the available energy was diverted to evaporation (a non-productive flux), while, at higher species richness, the proportion of ecosystem transpiration (a productivity-related water flux) increased. While it is well established that LAI controls ecosystem transpiration, here we also identified that the diversity of leaf nitrogen concentration among species in a community is a consistent predictor of ecosystem water vapor fluxes during daytime. The results provide evidence that, at the peak of the growing season, higher leaf area index (LAI) and lower percentage of bare ground at high plant diversity diverts more of the available water to transpiration, a flux closely coupled with photosynthesis and productivity. Higher rates of transpiration presumably contribute to the positive effect of diversity on productivity.

  18. Response of pest control by generalist predators to local-scale plant diversity: a meta-analysis.

    Science.gov (United States)

    Dassou, Anicet Gbèblonoudo; Tixier, Philippe

    2016-02-01

    Disentangling the effects of plant diversity on the control of herbivores is important for understanding agricultural sustainability. Recent studies have investigated the relationships between plant diversity and arthropod communities at the landscape scale, but few have done so at the local scale. We conducted a meta-analysis of 32 papers containing 175 independent measures of the relationship between plant diversity and arthropod communities. We found that generalist predators had a strong positive response to plant diversity, that is, their abundance increased as plant diversity increased. Herbivores, in contrast, had an overall weak and negative response to plant diversity. However, specialist and generalist herbivores differed in their response to plant diversity, that is, the response was negative for specialists and not significant for generalists. While the effects of scale remain unclear, the response to plant diversity tended to increase for specialist herbivores, but decrease for generalist herbivores as the scale increased. There was no clear effect of scale on the response of generalist predators to plant diversity. Our results suggest that the response of herbivores to plant diversity at the local scale is a balance between habitat and trophic effects that vary according to arthropod specialization and habitat type. Synthesis and applications. Positive effects of plant diversity on generalist predators confirm that, at the local scale, plant diversification of agroecosystems is a credible and promising option for increasing pest regulation. Results from our meta-analysis suggest that natural control in plant-diversified systems is more likely to occur for specialist than for generalist herbivores. In terms of pest management, our results indicate that small-scale plant diversification (via the planting of cover crops or intercrops and reduced weed management) is likely to increase the control of specialist herbivores by generalist predators.

  19. Geographic patterns of endemic seed plant genera diversity in China

    OpenAIRE

    Shengbin Chen; Zhiyun Ouyang; Yu Fang; Zhenji Li

    2011-01-01

    Endemism describes the phenomenon that the distribution of individual species/taxa is critically restricted to a specific region. Seed plant genera endemic to China (endemic genera) are those with their main geographic distribution range within the borders of China. The geographic patterns of endemic genera can not only guide conservation planning, but these organisms are also important biological resources. We gath-ered data of 173 localities on environmental and spatial factors, and regiona...

  20. Plants and People: Choices and Diversity Through Time

    OpenAIRE

    2014-01-01

    This first monograph in the EARTH series The dynamics of non-industrial agriculture: 8,000 years of resilience and innovation, approaches the great variety of agricultural practices in human terms. It focuses on the relationship between plants and people, the complexity of agricultural processes and their organisation within particular communities and societies. Collaborative European research among archaeologists, archaeobotanists, ethnographers, historians and agronomists using a broad anal...

  1. Plants and People: Choices and Diversity Through Time

    OpenAIRE

    2014-01-01

    This first monograph in the EARTH series The dynamics of non-industrial agriculture: 8,000 years of resilience and innovation, approaches the great variety of agricultural practices in human terms. It focuses on the relationship between plants and people, the complexity of agricultural processes and their organisation within particular communities and societies. Collaborative European research among archaeologists, archaeobotanists, ethnographers, historians and agronomists using a broad anal...

  2. Plant invasion and speciation along elevational gradients on the oceanic island La Palma, Canary Islands

    DEFF Research Database (Denmark)

    Steinbauer, Manuel; Irl, Severin David Howard; González-Mancebo, Juana Maria

    2017-01-01

    systematically along three elevational gradients covering large parts of the climatic range of La Palma, Canary Islands. Results: Species richness was negatively correlated with elevation, while the percentage of Canary endemic species showed a positive relationship. However, the percentage of Canary-Madeira...... from high elevations indicating directional ecological filtering. Increasing ecological isolation with elevation drives diversification and thus increased percentages of Canary endemics. The best preserved eastern transect, including mature laurel forests is an exception. The high percentage of Canary-Madeira...

  3. Acacia sieberiana Effects on Soil Properties and Plant Diversity in Songa Pastures, Rwanda

    Directory of Open Access Journals (Sweden)

    C. P. Mugunga

    2013-01-01

    Full Text Available Effects of A. sieberiana trees on soil properties and plant diversity were investigated in Songa pastures, Rwanda. Tree characteristics and crown architecture of A. sieberiana were studied. Soil properties were assessed and plants were identified under and away from tree crowns. Counts of individual plants/species were done only under tree crowns. Nitrogen, P, and K were analysed in the soil, grass, and A. sieberiana leaves. Plant diversity was determined using Simpson's diversity index. Data were subjected to ANOVA. Soil organic carbon (SOC, cation exchange capacity (CEC, Ca2+, N and pH, and plant diversity were higher in soils under tree canopies than in open areas. Tree leaves were significantly richer in N and poorer in P and K as compared to grasses. Tree crowns grew wider and horizontal and developed intertwined secondary branching, reducing light intensity to as low as 38% under tree canopies compared to the open pasture. At 3 trees/ha stocking, A. sieberiana trees shaded 0.18 ha and herbaceous plants and grasses unpalatable to livestock dominated under tree canopies. A tradeoff of A. sieberiana tree value versus the loss of palatable grass due to tree presence needs to be assessed to decide whether the trees should be included in pastures and if yes, the apporpriate stocking identified.

  4. Denaturing gradient electrophoresis (DGE) and single-strand conformation polymorphism (SSCP) molecular fingerprintings revisited by simulation and used as a tool to measure microbial diversity.

    Science.gov (United States)

    Loisel, Patrice; Harmand, Jérôme; Zemb, Olivier; Latrille, Eric; Lobry, Claude; Delgenès, Jean-Philippe; Godon, Jean-Jacques

    2006-04-01

    The exact extent of microbial diversity remains unknowable. Nevertheless, fingerprinting patterns [denaturing gradient electrophoresis (DGE), single-strand conformation polymorphism (SSCP)] provide an image of a microbial ecosystem and contain diversity data. We generated numerical simulation fingerprinting patterns based on three types of distribution (uniform, geometric and lognormal) with a range of units from 10 to 500,000. First, simulated patterns containing a diversity of around 1000 units or more gave patterns similar to those obtained in experiments. Second, the number of bands or peaks saturated quickly to about 35 and were unrelated to the degree of diversity. Finally, assuming lognormal distribution, we used an estimator of diversity on in silico and experimental fingerprinting patterns. Results on in silico patterns corresponded to the simulation inputs. Diversity results in experimental patterns were in the same range as those obtained from the same DNA sample in molecular inventories. Thus, fingerprinting patterns contain extractable data about diversity although not on the basis of a number of bands or peaks, as is generally assumed to be the case.

  5. Development of superconducting high gradient magnetic separation system for scale removal from feed-water in thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Shibatani, Saori; Nakanishi, Motohiro; Mizuno, Nobumi [Osaka University, Osaka (Japan); and others

    2016-03-15

    A Superconducting High Gradient Magnetic Separation (HGMS) system is proposed for treatment of feed-water in thermal power plant. This is a method to remove the iron scale from feed-water utilizing magnetic force. One of the issues for practical use of HGMS system is to extend continuous operation period. In this study, we designed the magnetic filters by particle trajectory simulation and HGMS experiments in order to solve this problem. As a result, the quantity of magnetite captured by each filter was equalized and filter blockage was prevented. A design method of the magnetic filter was proposed which is suitable for the long-term continuous scale removal in the feed-water system of the thermal power plant.

  6. Soil Properties and Plant Community Changes along a Goat Grazing Intensity Gradient in an Open Canopy Oak Forest

    Directory of Open Access Journals (Sweden)

    Aimilia LEMPESI

    2013-12-01

    Full Text Available Understanding how the management practices of silvopastoral systems affect the long-term sustainability of oak ecosystems and what their influence is on nutrient cycling and plant community, is of great interest. The aim of this study was to examine the effects of relative grazing intensity on soil properties and on vegetation characteristics in an open canopy oak forest dominated by Quercus frainetto. The research was conducted in the area of Pentalofos, which is located in Evros region, north-eastern Greece and is grazed by goats. The distance from a goat corral was used to represent relative grazing intensity. In June 2011, soil and vegetation samples were collected along transects placed at 50, 150, 300, 600 and 1200 m from the goat corral, running perpendicular to three replicates. Soil measurements included pH, phosphorous (P and nitrogen (N concentrations while vegetation measurements included plant cover, species composition and diversity. Plant cover was not significantly different among grazing intensities. Species diversity, especially of the woody vegetation layer, was significantly higher in the light grazing intensity in comparison to both the heavy and the very light grazing. Heavy grazing reduced soil organic matter while it increased total nitrogen. Grazing intensity did not affect available P and soil pH. Light to moderate goat grazing could ameliorate floristic diversity and increase sustainability of oak forests in the Mediterranean region.

  7. Effects of Bamboo Fargesia murielae on Plant Diversity in Fir Forest on Mountain Shennongjia

    Institute of Scientific and Technical Information of China (English)

    Li Zhaohua; Manfred Denich; Thomas Borsch

    2004-01-01

    Simultaneous flowering caused a gregarious dieback of umbrella bamboo (Fargesia murielae) all over the world in 1993-2000. Mountain Shennongjia in Central China's Hubei Province is the only native home of umbrella bamboo, where it dominates the understorey of the farges fir (Abies fargesii) forest between 2 400 and 3 100 m, covering the ground for more than one century before a periodically flowering death. Data from 20 quadrats along a vegetation sequence revealed that the density, coverage, and height of umbrella bamboo negatively affected the species richness, diversity, and evenness of vascular plants in the forest. Local climax community of fir-bamboo was the poorest in species diversity, while the bamboo-free communities (i.e. shrubs and meadows) were bearing a higher species diversity. The simultaneous dieback of umbrella bamboo is an ecological release, which can periodically promote the plant diversity in the fir forest.

  8. Diversity of arbuscular mycorrhizal fungi in grassland spontaneously developed on area polluted by a fertilizer plant

    Energy Technology Data Exchange (ETDEWEB)

    Renker, C. [Institute of Ecology, Department of Environmental Sciences, University of Jena, Dornburger Str. 159, D-07743 Jena (Germany)]. E-mail: crenker@uni-leipzig.de; Blanke, V. [Institute of Ecology, Department of Environmental Sciences, University of Jena, Dornburger Str. 159, D-07743 Jena (Germany); Buscot, F. [Institute of Ecology, Department of Environmental Sciences, University of Jena, Dornburger Str. 159, D-07743 Jena (Germany)

    2005-05-01

    Mycorrhizal colonization and diversity of arbuscular mycorrhizal fungi (AMF) were analyzed in a calcareous grassland with residual phosphate contamination 10 years after the closure of a pollutant fertilizer plant in Thuringia (Germany). AMF were detected in 21 of 22 plant species analyzed. Mean mycorrhization levels reached up to 74.5% root length colonized. AMF diversity was analyzed based on 104 sequences of the internal transcribed spacer (ITS) of the ribosomal DNA. Phylogenetic analyses revealed a total of 6 species all belonging to the genus Glomus. There was no overlap between species detected as active mycorrhizas on roots (2 taxa) or as spores (4 taxa). Compared to the regional context, the diversity of AMF at our field site was reduced, which may reflect a residual disturbance effect. However, none of the detected species was exclusive to the polluted site as they are commonly found in the region. - Almost all plant species were mycorrhizal.

  9. Long-term persistence of a positive plant diversity-productivity relationship in the absence of legumes

    NARCIS (Netherlands)

    Ruijven, van J.; Berendse, F.

    2009-01-01

    Most studies investigating the relationship between plant diversity and ecosystem functioning lasted only a few years. These studies generally showed a positive relationship between diversity and productivity that strengthened with time. This pattern suggests the experimental communities have not ye

  10. Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model

    NARCIS (Netherlands)

    Sakschewski, B.; Bloh, von W.; Boit, A.; Rammig, A.; Kattge, J.; Poorter, L.; Peñualeas, J.; Thonicke, K.

    2015-01-01

    Functional diversity is critical for ecosystem dynamics, stability and productivity. However, dynamic global vegetation models (DGVMs) which are increasingly used to simulate ecosystem functions under global change, condense functional diversity to plant functional types (PFTs) with constant paramet

  11. Functional traits reveal the expansion and packing of ecological niche space underlying an elevational diversity gradient in passerine birds

    NARCIS (Netherlands)

    Pigot, Alex L.; Trisos, Christopher H.; Tobias, Joseph A.

    2016-01-01

    Variation in species richness across environmental gradients may be associated with an expanded volume or increased packing of ecological niche space. However, the relative importance of these alternative scenarios remains unknown, largely because standardized information on functional traits and th

  12. Functional traits reveal the expansion and packing of ecological niche space underlying an elevational diversity gradient in passerine birds

    NARCIS (Netherlands)

    Pigot, Alex L.; Trisos, Christopher H.; Tobias, Joseph A.

    2016-01-01

    Variation in species richness across environmental gradients may be associated with an expanded volume or increased packing of ecological niche space. However, the relative importance of these alternative scenarios remains unknown, largely because standardized information on functional traits and

  13. Nuclear material safeguards for enrichments plants: Part 4, Gas Centrifuge Enrichment Plant: Diversion scenarios and IAEA safeguards activities: Safeguards training course

    Energy Technology Data Exchange (ETDEWEB)

    1988-10-01

    This publication is Part 4 of a safeguards training course in Nuclear Material Safeguards for enrichment plants. This part of the course deals with diversion scenarios and safeguards activities at gas centrifuge enrichment plants.

  14. Plant community diversity influences allocation to direct chemical defence in Plantago lanceolata.

    Directory of Open Access Journals (Sweden)

    Anne Mraja

    Full Text Available BACKGROUND: Forecasting the consequences of accelerating rates of changes in biodiversity for ecosystem functioning requires a mechanistic understanding of the relationships between the structure of biological communities and variation in plant functional characteristics. So far, experimental data of how plant species diversity influences the investment of individual plants in direct chemical defences against herbivores and pathogens is lacking. METHODOLOGY/PRINCIPAL FINDINGS: We used Plantago lanceolata as a model species in experimental grasslands differing in species richness and composition (Jena Experiment to investigate foliar concentrations of the iridoid glycosides (IG, catalpol and its biosynthetic precursor aucubin. Total IG and aucubin concentrations decreased, while catalpol concentrations increased with increasing plant diversity in terms of species or functional group richness. Negative plant diversity effects on total IG and aucubin concentrations correlated with increasing specific leaf area of P. lanceolata, suggesting that greater allocation to light acquisition reduced the investment into these carbon-based defence components. In contrast, increasing leaf nitrogen concentrations best explained increasing concentrations of the biosynthetically more advanced IG, catalpol. Observed levels of leaf damage explained a significant proportion of variation in total IG and aucubin concentrations, but did not account for variance in catalpol concentrations. CONCLUSIONS/SIGNIFICANCE: Our results clearly show that plants growing in communities of varying species richness and composition differ in their defensive chemistry, which may modulate plant susceptibility to enemy attack and consequently their interactions with higher trophic level organisms.

  15. Grazing intensity on the plant diversity of alpine meadow in the eastern Tibetan plateau

    Directory of Open Access Journals (Sweden)

    Wu Ning

    2004-04-01

    Full Text Available Because ofthe remoteness and harsh conditions of the high-altitude rangelands on the eastern Tibetan Plateau, the relationship between yak grazing and plant diversity has not been so clear although livestock increase was thought as the main issue leading to the degradation of rangeland. In the debate of rangeland degradation, biodiversity loss has been assumed as one of the indicators in the last two decades. In this paper authors measured the effects of different grazing intensities on the plant diversity and the structure of Kobresia pygmaea community in the case-study area, northwestern Sichuan. The results indicated that plant diversity of alpine meadow has different changing trends respectively with the change of grazing intensity and seasons. In June the highest plant diversity occurred in the intensively grazed (HG plots, but in July and September species biodiversity index of slightly grazed (LG plots is higher than other experimental treatments. In August the intermediate grazed (IG plots has the highest biodiversity index. Moreover, it was found that intensively grazing always leads to the increase of plant density, but meanwhile the decrease of community height, coverage and biomass. Over-grazing can change the community structure and lead to the succession from Kobresia pygmaea dominated community to Poa pratensis dominated. Analyzing results comprehensively, it can be suggested that the relationship between grazing intensity and plant diversity is not linear, i.e. diversity index is not as good as other characteristics of community structure to evaluate rangeland degradation on the high altitude situation. The change of biodiversity is so complicated that it can not be explained with the simple corresponding causality.

  16. Does the stress-gradient hypothesis hold water? Disentangling spatial and temporal variation in plant effects on soil moisture in dryland systems

    Science.gov (United States)

    Butterfield, Bradley J.; Bradford, John B.; Armas, Cristina; Prieto, Ivan; Pugnaire, Francisco I.

    2016-01-01

    The nature of the relationship between water limitation and facilitation has been one of the most contentious debates surrounding the stress-gradient hypothesis (SGH), which states that plant-plant interactions shift from competition to facilitation with increasing environmental stress.

  17. Diversity of Endophytic Fungi from Red Ginger (Zingiber officinale Rosc.) Plant and Their Inhibitory Effect to Fusarium oxysporum Plant Pathogenic Fungi

    OpenAIRE

    SIHEGIKO KANAYA; LATIFAH KOSIM DARUSMAN; NAMPIAH SUKARNO; UTUT WIDYASTUTI; ROHANI CINTA BADIA GINTING

    2013-01-01

    Indonesia has been known as a country with high medicinal plant diversity. One of the most common medicinal plant from Indonesia is red ginger (Zingiber officinale Rosc.). Nevertheless, limited studies of endophytic fungi associated with these medicinal plants are hitherto available. The objectives of this research were to study the diversity of endophytic fungi on red ginger and to analyze their potential as a source of antifungal agent. All parts of plant organs such as leaf, rhizome, root,...

  18. Using dark diversity and plant characteristics to guide conservation and restoration

    DEFF Research Database (Denmark)

    Moeslund, Jesper Erenskjold; Brunbjerg, Ane Kirstine; Clausen, Kevin

    2017-01-01

    more often than others, although this is important knowledge for restoration and conservation actions. 2. We applied the concept to a massive national (Danish) plant diversity data base, containing 236 923 records from 15 160 surveys involving 564 species. This enabled the first geographically...... comprehensive (43 000 km2) assessment of dark diversity, at a spatial resolution relevant for conservation and restoration planning (78 m2) across multiple terrestrial habitats, thereby maximising the practical applications of this concept. The probability for a given plant species to belong to the dark...

  19. Plant morphometric traits and climate gradients in northern China: a meta-analysis using quadrat and flora data.

    Science.gov (United States)

    Meng, Ting-Ting; Ni, Jian; Harrison, Sandy P

    2009-11-01

    The collection of field data on plant traits is time consuming and this makes it difficult to examine changing patterns of traits along large-scale climate gradients. The present study tests whether trait information derived from regional floras can be used in conjunction with pre-existing quadrat data on species presence to derive meaningful relationships between specific morphometric traits and climate. Quadrat records were obtained for 867 species in 404 sites from northern China (38-49 degrees N, 82-132 degrees E) together with information on the presence/absence of key traits from floras. Bioclimate parameters for each site were calculated using the BIOME3 model. Principal component analysis and correlation analysis were conducted to determine the most important climate factors. The Akaike Information Criterion was used to select the best relationship between each trait and climate. Canonical correspondence analysis was used to explore the relationships between climate and trait occurrence. The changing abundance of life form, leaf type, phenology, photosynthetic pathway, leaf size and several other morphometric traits are determined by gradients in plant-available moisture (as measured by the ratio of actual to potential evapotranspiration: alpha), growing-season temperature (as measured by growing degree-days on a 0 degrees base: GDD(0)) or a combination of these. Different plant functional types (PFTs, as defined by life form, leaf type and phenology) reach maximum abundance in distinct areas of this climate space: for example, evergreen trees occur in the coldest, wettest environments (GDD(0) 0.38), and deciduous scale-leaved trees occur in drier, warmer environments than deciduous broad-leaved trees. Most leaf-level traits show similar relationships with climate independently of PFT: for example, leaf size in all PFTs increases as the environment becomes wetter and cooler. However, some traits (e.g. petiole length) display different relationships with

  20. Diverse Functional Roles of Monosaccharide Transporters and their Homologs in Vascular Plants: A Physiological Perspective

    Institute of Scientific and Technical Information of China (English)

    Thomas L. Slewinski

    2011-01-01

    Vascular plants contain two gene families that encode monosaccharide transporter proteins. The classical monosaccharide transporter(-like)gene superfamily is large and functionally diverse, while the recently identified SWEET transporter family is smaller and, thus far, only found to transport glucose. These transporters play essential roles at many levels, ranging from organelles to the whole plant. Many family members are essential for cellular homeostasis and re-productive success. Although most transporters do not directly participate in long-distance transport, their indirect roles greatly impact carbon allocation and transport flux to the heterotrophic tissues of the plant. Functional characterization of some members from both gene families has revealed their diverse roles in carbohydrate partitioning, phloem function,resource allocation, plant defense, and sugar signaling. This review highlights the broad impacts and implications of monosaccharide transport by describing some of the functional roles of the monosaccharide transporter(-like)superfamily and the SWEET transporter family.

  1. Diversity of Endophytic Bacterial Populations and Their Interaction with Xylella fastidiosa in Citrus Plants

    OpenAIRE

    Araujo, W.L.; Marcon, J; Maccheroni, jr., W.; Elsas, van, J.D.; Vuurde, van, M.; Azevedo

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by ...

  2. Using phylogenetic, functional and trait diversity to understand patterns of plant community productivity.

    Directory of Open Access Journals (Sweden)

    Marc W Cadotte

    Full Text Available BACKGROUND: Two decades of research showing that increasing plant diversity results in greater community productivity has been predicated on greater functional diversity allowing access to more of the total available resources. Thus, understanding phenotypic attributes that allow species to partition resources is fundamentally important to explaining diversity-productivity relationships. METHODOLOGY/PRINCIPAL FINDINGS: Here we use data from a long-term experiment (Cedar Creek, MN and compare the extent to which productivity is explained by seven types of community metrics of functional variation: 1 species richness, 2 variation in 10 individual traits, 3 functional group richness, 4 a distance-based measure of functional diversity, 5 a hierarchical multivariate clustering method, 6 a nonmetric multidimensional scaling approach, and 7 a phylogenetic diversity measure, summing phylogenetic branch lengths connecting community members together and may be a surrogate for ecological differences. Although most of these diversity measures provided significant explanations of variation in productivity, the presence of a nitrogen fixer and phylogenetic diversity were the two best explanatory variables. Further, a statistical model that included the presence of a nitrogen fixer, seed weight and phylogenetic diversity was a better explanation of community productivity than other models. CONCLUSIONS: Evolutionary relationships among species appear to explain patterns of grassland productivity. Further, these results reveal that functional differences among species involve a complex suite of traits and that perhaps phylogenetic relationships provide a better measure of the diversity among species that contributes to productivity than individual or small groups of traits.

  3. Strong species-environment feedback shapes plant community assembly along environmental gradients

    Science.gov (United States)

    Jiang, Jiang; DeAngelis, Donald L.

    2013-01-01

    An aim of community ecology is to understand the patterns of competing species assembly along environmental gradients. All species interact with their environments. However, theories of community assembly have seldom taken into account the effects of species that are able to engineer the environment. In this modeling study, we integrate the species' engineering trait together with processes of immigration and local dispersal into a theory of community assembly. We quantify the species' engineering trait as the degree to which it can move the local environment away from its baseline state towards the optimum state of the species (species-environment feedback). We find that, in the presence of immigration from a regional pool, strong feedback can increase local species richness; however, in the absence of continual immigration, species richness is a declining function of the strength of species-environment feedback. This shift from a negative effect of engineering strength on species richness to a positive effect, as immigration rate increases, is clearer when there is spatial heterogeneity in the form of a gradient in environmental conditions than when the environment is homogeneous or it is randomly heterogeneous. Increasing the scale over which local dispersal occurs can facilitate species richness when there is no species-environment feedback or when the feedback is weak. However, increases in the spatial scale of dispersal can reduce species richness when the species-environment feedback is strong. These results expand the theoretical basis for understanding the effects of the strength of species-environment feedback on community assembly.

  4. Species Diversity in Northern California Salt Marshes: Functional Significance of Parasitic Plant Interactions

    OpenAIRE

    Grewell, Brenda J.

    2004-01-01

    I studied how parasitic plant interactions contribute to species coexistence in tidal wetlands of northern California. First, I address the effects of the native parasite Cuscuta salina on species interactions and plant community structure, showed that Cuscuta is restricted to nutrient poor areas with significant canopy gaps and high species diversity. I examined timing, level, and frequency of host infectivity and identified Plantago maritima as the primary host. I experimentally removed Cus...

  5. Species diversity of vascular plants in Si Phang-nga National Park, Phangnga Province

    Directory of Open Access Journals (Sweden)

    Leeratiwong, C.

    2005-07-01

    Full Text Available A survey of the vascular plants in Si Phang-nga National Park, Phangnga Province, was conducted from September 2002 to August 2003. Five hundred and forty three species of 287 genera and 111 families were collected. The most diverse family was Rubiaceae, 53 species. Four species of these collected plants are endemic to Thailand, Argostemma lobulatum, Aristolochia helix, Crinum thaianum and Mallotus hymenophyllus and three species, Hedyotis hedyotidea, Lipocarpha microcephala and Pterolobium intergum are newly recorded for southern Thailand.

  6. Plants diversity and its potential in Buton Utara Game Reserve, South-East Sulawesi

    Directory of Open Access Journals (Sweden)

    TAHAN UJI

    2005-07-01

    Full Text Available Study on richness diversity and potential species of plant in two locations in the Buton Utara Game Reserve had been conducted. One hundred and seventy nine species of plant are collected from this area, and 137 species of them are reported as the potential of species. The largest group is timber (76 species and the other is medicinal plants (41 species. Other data can be gathered as follows 23 species of fruits, 22 species of ornamental plants, 12 species of vegetable, 7 species of fibre plants and 5 species of poisonous plants. The results of study indicated that biti/owala (Vitex coffasus, upi (Intsia palembanica, gufi (Intsia bijuga, nato (Palaquium bataanense, kuru (Elmerillia ovalis, keu uti (Drypetes sibuyanensis, rumbai (Pterospermum celebicum, kondongia (Cinnamomum parthenoxylon, and dongi (Dillenia serrata were very important as commercial timbers.

  7. Highly diverse endophytic and soil Fusarium oxysporum populations associated with field-grown tomato plants.

    Science.gov (United States)

    Demers, Jill E; Gugino, Beth K; Jiménez-Gasco, María Del Mar

    2015-01-01

    The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants. Included in this total were 112 isolates from the stems of all 32 plants, a niche that has not been previously included in F. oxysporum population genetics studies. Isolates were characterized using the DNA sequence of the translation elongation factor 1α gene. A diverse population of 26 sequence types was found, although two sequence types represented nearly two-thirds of the isolates studied. The sequence types were placed in different phylogenetic clades within F. oxysporum, and endophytic isolates were not monophyletic. Multiple sequence types were found in all plants, with an average of 4.2 per plant. The population compositions differed between the two fields but not between soil samples within each field. A certain degree of differentiation was observed between populations associated with different tomato cultivars, suggesting that the host genotype may affect the composition of plant-associated F. oxysporum populations. No clear patterns of genetic differentiation were observed between endophyte populations and soil populations, suggesting a lack of specialization of endophytic isolates. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Organic, integrated and conventional management in apple orchards: effect on plant species composition, richness and diversity

    Directory of Open Access Journals (Sweden)

    Zdeňka Lososová

    2011-01-01

    Full Text Available The study was conducted to assess the effect of conventional, integrated and organic management on differences in plant species composition, richness and diversity. The plants were studied in triads of orchards situated in three regions of the Czech Republic. Data about species occurrences were collected on 15 permanent plots in the tree rows and 15 plots between tree rows in each of the apple orchards during 2009. A total of 201 vascular plant species (127 native species, 65 archaeophytes, and 9 neophytes were found. Management type and also different regional conditions had a significant effect on plant species composition and on diversity parameters of orchard spontaneous vegetation. Species richness and species pool was significantly higher in the organic orchards than in the differently managed orchards. Management type had significant effect on proportions of archaeophytes, and also neophytes in apple orchards. The results showed that a change from conventional to integrated and organic management in apple orchards lead to higher plant species diversity and to changes in plant species composition.

  9. Analysis of genetic diversity of a native population of Myrcia lundiana Kiaersk. plants using ISSR markers.

    Science.gov (United States)

    Alves, M F; Nizio, D A C; Brito, F A; Sampaio, T S; Silva, A V C; Arrigoni-Blank, M F; Carvalho, S V A; Blank, A F

    2016-12-02

    Myrcia lundiana Kiaersk. is a tree of the family Myrtaceae found in tropical and subtropical areas of the southern hemisphere that produces essential oil. The aim of this study was to characterize the genetic diversity of M. lundiana plants from a native population of Parque Nacional de Itabaiana, using inter-simple sequence repeat molecular markers. Thirty-five primers were tested, 20 of which were polymorphic, resulting in 135 polymorphic and informative bands. Results of the cluster analysis, obtained using the unweighted pair group method with arithmetic mean, grouped plants into three clusters: Cluster I - MLU001, MLU002, MLU003, MLU004, MLU005, MLU006, MLU018, MLU019, MLU020, MLU021, MLU022; MLU008, MLU011, MLU012, MLU014, MLU015, MLU017, MLU026, and MLU028; Cluster II - MLU007, MLU009, MLU010, MLU013, and MLU016; and Cluster III - MLU023, MLU024, MLU025, and MLU027. Jaccard similarity coefficients for pair-wise comparisons of plants ranged between 0.15 and 0.87. MLU014 and MLU015 presented low genetic diversity, with a similarity index of 0.87. Conversely, MLU007 and MLU019 presented high diversity, with a similarity index of 0.15. According to the structure analysis, three distinct clusters were formed. Genetic diversity of M. lundiana plants was intermediate, and expansion of its genetic diversity is necessary. MLU026 and MLU028 are the most suitable for selection in breeding programs, since they clearly represent all of the diversity present in these plants. Moreover, these results provide important information on the existing genetic variability, highlighting the importance of Parque Nacional de Itabaiana for the conservation of this species.

  10. Trade-offs between savanna woody plant diversity and carbon storage in the Brazilian Cerrado.

    Science.gov (United States)

    Pellegrini, Adam F A; Socolar, Jacob B; Elsen, Paul R; Giam, Xingli

    2016-10-01

    Incentivizing carbon storage can be a win-win pathway to conserving biodiversity and mitigating climate change. In savannas, however, the situation is more complex. Promoting carbon storage through woody encroachment may reduce plant diversity of savanna endemics, even as the diversity of encroaching forest species increases. This trade-off has important implications for the management of biodiversity and carbon in savanna habitats, but has rarely been evaluated empirically. We quantified the nature of carbon-diversity relationships in the Brazilian Cerrado by analyzing how woody plant species richness changed with carbon storage in 206 sites across the 2.2 million km(2) region at two spatial scales. We show that total woody plant species diversity increases with carbon storage, as expected, but that the richness of endemic savanna woody plant species declines with carbon storage both at the local scale, as woody biomass accumulates within plots, and at the landscape scale, as forest replaces savanna. The sharpest trade-offs between carbon storage and savanna diversity occurred at the early stages of carbon accumulation at the local scale but the final stages of forest encroachment at the landscape scale. Furthermore, the loss of savanna species quickens in the final stages of forest encroachment, and beyond a point, savanna species losses outpace forest species gains with increasing carbon accumulation. Our results suggest that although woody encroachment in savanna ecosystems may provide substantial carbon benefits, it comes at the rapidly accruing cost of woody plant species adapted to the open savanna environment. Moreover, the dependence of carbon-diversity trade-offs on the amount of savanna area remaining requires land managers to carefully consider local conditions. Widespread woody encroachment in both Australian and African savannas and grasslands may present similar threats to biodiversity.

  11. Plant Diversity in Live Fences and Pastures, Two Examples from the Mexican Humid Tropics

    Science.gov (United States)

    Ruiz-Guerra, Betsabé; Rosas, Noé Velázquez; López-Acosta, Juan Carlos

    2014-09-01

    This study analyzes the potential uses of live fences and pastures as reservoirs of plant diversity for two regions with different management histories, Los Tuxtlas (LT) and Uxpanapa (UX), Veracruz, México. We studied two habitats, live fences and pastures, analyzed their species richness, diversity, structure and plant composition and classified species according to plant regeneration modes (light-demanding and shade tolerant), seed dispersal syndrome and their local uses. We recorded 62 species of trees at LT and 48 at UX. Live fences were more diverse than pastures in both regions. The LT site showed to analyze the relationship a higher diversity of plants in regeneration stages than the one at UX. However, UX had higher diversity of adult plants in the pastures than LT. Composition and structure of live fences were different between regions, as well as within live fences and pastures, 53 % of species were light-demanding and 40 % were shade tolerant; 70 % of the species were dispersed by birds. Differences between sites are associated with the modifications in live fences structure, which changed according to managerial practices and the use of local species; this may influence plant regeneration modes as well as the visits of avian dispersal agents. In LT, all species found in live fences were useful to humans, whereas in UX, less than half were used by the local population. Our results underline the importance of live fences and isolated trees in pasture habitats as potential sites to host native and useful species from tropical rain forests in livestock landscapes.

  12. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

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    Bonnie M McGill

    Full Text Available BACKGROUND: Denitrification is an important ecosystem service that removes nitrogen (N from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3(- and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1 Does DEA vary through the growing season? (2 If so, can we predict DEA variability with environmental variables? (3 Does plant functional diversity affect DEA variability? METHODOLOGY/PRINCIPAL FINDINGS: The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001. Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001. Of the soil variables measured--soil moisture, organic ma