Science.gov

Sample records for assess plant diversity

  1. A Brief Review of Molecular Techniques to Assess Plant Diversity

    PubMed Central

    Arif, Ibrahim A.; Bakir, Mohammad A.; Khan, Haseeb A.; Al Farhan, Ahmad H.; Al Homaidan, Ali A.; Bahkali, Ali H.; Sadoon, Mohammad Al; Shobrak, Mohammad

    2010-01-01

    Massive loss of valuable plant species in the past centuries and its adverse impact on environmental and socioeconomic values has triggered the conservation of plant resources. Appropriate identification and characterization of plant materials is essential for the successful conservation of plant resources and to ensure their sustainable use. Molecular tools developed in the past few years provide easy, less laborious means for assigning known and unknown plant taxa. These techniques answer many new evolutionary and taxonomic questions, which were not previously possible with only phenotypic methods. Molecular techniques such as DNA barcoding, random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), microsatellites and single nucleotide polymorphisms (SNP) have recently been used for plant diversity studies. Each technique has its own advantages and limitations. These techniques differ in their resolving power to detect genetic differences, type of data they generate and their applicability to particular taxonomic levels. This review presents a basic description of different molecular techniques that can be utilized for DNA fingerprinting and molecular diversity analysis of plant species. PMID:20559503

  2. PLANT DIVERSITY

    EPA Science Inventory

    Habitat change statistics and species-area curves were used to estimate the effects of alternative future scenarios for agriculture on plant diversity in Iowa farmlands. Study areas were two watersheds in central Iowa of about 50 and 90 square kilometers, respectively. Future s...

  3. Assessing the diversity of bacterial communities associated with plants

    PubMed Central

    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

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

    PubMed

    Bobbink, R; Hicks, K; Galloway, J; Spranger, T; Alkemade, R; Ashmore, M; Bustamante, M; Cinderby, S; Davidson, E; Dentener, F; Emmett, B; Erisman, J-W; Fenn, M; Gilliam, F; Nordin, A; Pardo, L; De Vries, 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 of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such as direct toxicity of nitrogen gases and aerosols, long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem- and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition, and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America, especially for the more sensitive ecosystem types, including several ecosystems of high conservation importance. The results of this assessment show that the vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe), and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted studies are required in low background areas, especially in the G200 ecoregions. PMID:20349829

  5. Evolution & Diversity in Plants.

    ERIC Educational Resources Information Center

    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)

  6. Palaeo plant diversity in subtropical Africa - ecological assessment of a conceptual model of climate-vegetation interaction

    NASA Astrophysics Data System (ADS)

    Groner, V. P.; Claussen, M.; Reick, C.

    2015-07-01

    We here critically re-assess a conceptual model dealing with the potential effect of plant diversity on climate-vegetation feedback, and provide an improved version adjusted to plant types that prevailed during the African Humid Period (AHP). Our work contributes to the understanding of the timing and abruptness of vegetation decline at the end of the AHP, investigated by various working groups during the past two decades using a wide range of model and palaeoproxy reconstruction approaches. While some studies indicated an abrupt collapse of vegetation at the end of the AHP, others suggested a gradual decline. Claussen et al. (2013) introduced a new aspect in the discussion, proposing that plant diversity in terms of moisture requirements could affect the strength of climate-vegetation feedback. In a conceptual model study, the authors illustrated that high plant diversity could stabilize an ecosystem, whereas a reduction in plant diversity might allow for an abrupt regime shift under gradually changing environmental conditions. Based on recently published pollen data and the current state of ecological literature, we evaluate the representation of climate-vegetation feedback in this conceptual approach, and put the suggested conclusions into an ecological context. In principle, the original model reproduces the main features of different plant types interacting together with climate although vegetation determinants other than precipitation are neglected. However, the model cannot capture the diversity of AHP vegetation. Especially tropical gallery forest taxa, indirectly linked to local precipitation, are not appropriately represented. In order to fill the gaps in the description of plant types regarding AHP diversity, we modify the original model in four main aspects. First, the growth ranges in terms of moisture requirements are extended by upper limits to represent full environmental envelopes. Second, data-based AHP plant types replace the hypothetical plant types. Third, the tropical gallery forest type follows the gradual insolation forcing with a linear approximation because it relies more on large scale climate than on regional precipitation amounts. Fourth, we replace the dimensionless vegetation cover fractions with individual effective leaf areas to capture different contributions to climate-vegetation feedback. These adjustments allow for the consideration of a broader spectrum of plant types, plant-climate feedbacks, and implicitly for plant-plant interactions. With the consideration of full environmental envelopes and the prescribed retreat of the tropical gallery forest type we can simulate a diverse mosaic-like environment as it was reconstructed from pollen. Transient simulations of this diverse environment support the buffering effect of high functional diversity on ecosystem performance and precipitation, concluded by Claussen et al. (2013) from the simple approach. Sensitivity studies with different combinations of plant types highlight the importance of plant composition on system stability, and the stabilizing or destabilizing potential a single functional type may inherit. In a broader view, the adjusted model provides a useful tool to study the roles of real plant types in an ecosystem and their combined climate-vegetation feedback under changing precipitation regimes.

  7. Phytochemical diversity drives plant-insect community diversity.

    PubMed

    Richards, Lora A; Dyer, Lee A; Forister, Matthew L; Smilanich, Angela M; Dodson, Craig D; Leonard, Michael D; Jeffrey, Christopher S

    2015-09-01

    What are the ecological causes and consequences of variation in phytochemical diversity within and between plant taxa? Despite decades of natural products discovery by organic chemists and research by chemical ecologists, our understanding of phytochemically mediated ecological processes in natural communities has been restricted to studies of either broad classes of compounds or a small number of well-characterized molecules. Until now, no studies have assessed the ecological causes or consequences of rigorously quantified phytochemical diversity across taxa in natural systems. Consequently, hypotheses that attempt to explain variation in phytochemical diversity among plants remain largely untested. We use spectral data from crude plant extracts to characterize phytochemical diversity in a suite of co-occurring plants in the tropical genus Piper (Piperaceae). In combination with 20 years of data focused on Piper-associated insects, we find that phytochemical diversity has a direct and positive effect on the diversity of herbivores but also reduces overall herbivore damage. Elevated chemical diversity is associated with more specialized assemblages of herbivores, and the cascading positive effect of phytochemistry on herbivore enemies is stronger as herbivore diet breadth narrows. These results are consistent with traditional hypotheses that predict positive associations between plant chemical diversity, insect herbivore diversity, and trophic specialization. It is clear from these results that high phytochemical diversity not only enhances the diversity of plant-associated insects but also contributes to the ecological predominance of specialized insect herbivores. PMID:26283384

  8. Importance of genetic diversity assessment in crop plants and its recent advances: an overview of its analytical perspectives.

    PubMed

    Govindaraj, M; Vetriventhan, M; Srinivasan, M

    2015-01-01

    The importance of plant genetic diversity (PGD) is now being recognized as a specific area since exploding population with urbanization and decreasing cultivable lands are the critical factors contributing to food insecurity in developing world. Agricultural scientists realized that PGD can be captured and stored in the form of plant genetic resources (PGR) such as gene bank, DNA library, and so forth, in the biorepository which preserve genetic material for long period. However, conserved PGR must be utilized for crop improvement in order to meet future global challenges in relation to food and nutritional security. This paper comprehensively reviews four important areas; (i) the significance of plant genetic diversity (PGD) and PGR especially on agriculturally important crops (mostly field crops); (ii) risk associated with narrowing the genetic base of current commercial cultivars and climate change; (iii) analysis of existing PGD analytical methods in pregenomic and genomic era; and (iv) modern tools available for PGD analysis in postgenomic era. This discussion benefits the plant scientist community in order to use the new methods and technology for better and rapid assessment, for utilization of germplasm from gene banks to their applied breeding programs. With the advent of new biotechnological techniques, this process of genetic manipulation is now being accelerated and carried out with more precision (neglecting environmental effects) and fast-track manner than the classical breeding techniques. It is also to note that gene banks look into several issues in order to improve levels of germplasm distribution and its utilization, duplication of plant identity, and access to database, for prebreeding activities. Since plant breeding research and cultivar development are integral components of improving food production, therefore, availability of and access to diverse genetic sources will ensure that the global food production network becomes more sustainable. The pros and cons of the basic and advanced statistical tools available for measuring genetic diversity are briefly discussed and their source links (mostly) were provided to get easy access; thus, it improves the understanding of tools and its practical applicability to the researchers. PMID:25874132

  9. Importance of Genetic Diversity Assessment in Crop Plants and Its Recent Advances: An Overview of Its Analytical Perspectives

    PubMed Central

    Govindaraj, M.; Vetriventhan, M.; Srinivasan, M.

    2015-01-01

    The importance of plant genetic diversity (PGD) is now being recognized as a specific area since exploding population with urbanization and decreasing cultivable lands are the critical factors contributing to food insecurity in developing world. Agricultural scientists realized that PGD can be captured and stored in the form of plant genetic resources (PGR) such as gene bank, DNA library, and so forth, in the biorepository which preserve genetic material for long period. However, conserved PGR must be utilized for crop improvement in order to meet future global challenges in relation to food and nutritional security. This paper comprehensively reviews four important areas; (i) the significance of plant genetic diversity (PGD) and PGR especially on agriculturally important crops (mostly field crops); (ii) risk associated with narrowing the genetic base of current commercial cultivars and climate change; (iii) analysis of existing PGD analytical methods in pregenomic and genomic era; and (iv) modern tools available for PGD analysis in postgenomic era. This discussion benefits the plant scientist community in order to use the new methods and technology for better and rapid assessment, for utilization of germplasm from gene banks to their applied breeding programs. With the advent of new biotechnological techniques, this process of genetic manipulation is now being accelerated and carried out with more precision (neglecting environmental effects) and fast-track manner than the classical breeding techniques. It is also to note that gene banks look into several issues in order to improve levels of germplasm distribution and its utilization, duplication of plant identity, and access to database, for prebreeding activities. Since plant breeding research and cultivar development are integral components of improving food production, therefore, availability of and access to diverse genetic sources will ensure that the global food production network becomes more sustainable. The pros and cons of the basic and advanced statistical tools available for measuring genetic diversity are briefly discussed and their source links (mostly) were provided to get easy access; thus, it improves the understanding of tools and its practical applicability to the researchers. PMID:25874132

  10. Geographic information system method for assessing chemo-diversity in medicinal plants.

    PubMed

    Moraes, Rita M; Momm, Henrique G; Silva, Bladimiro; Maddox, Victor; Easson, Gregory L; Lata, Hemant; Ferreira, Daneel

    2005-12-01

    The spatial distribution of wild germplasm of Podophyllum peltatum L. (American mayapple) has been analyzed using the Geographic Information System (GIS) with the objective to develop a method and a database for evaluation of biotic and abiotic factors influencing drug yield, and to map elite genotypes for propagation and improvement. The field assessment followed a standard procedure including geographical coordinates of each accession, leaf biomass randomly harvested, identification of associate species, collection of herbarium specimen, soil sample and digital pictures of the site. By overlaying morphological and chemical data with geomorphic information, a thematic map was created locating the podophyllotoxin-rich accessions and the uniqueness of each site was recorded for post-collection analysis. This work has enabled the establishment of a database of P. peltatum germplasm in Mississippi with drug yield linked to spatial locations for rational utilization of our natural resources. While this method integrates information of well-characterized diverse in situ P. peltatum germplasm, it might become a strategy for curators to reduce cost for establishing and maintaining ex situ collections since the genetic material is geo-referenced. PMID:16395654

  11. Palaeo plant diversity in subtropical Africa - ecological assessment of a conceptual model of climate-vegetation interaction

    NASA Astrophysics Data System (ADS)

    Groner, V. P.; Claussen, M.; Reick, C.

    2015-10-01

    We critically reassess a conceptual model here, dealing with the potential effect of plant diversity on climate-vegetation feedback, and we provide an improved version adjusted to plant types that prevailed during the African Humid Period (AHP). Our work contributes to the understanding of the timing and abruptness of vegetation decline at the end of the AHP, investigated by various working groups during the past 2 decades using a wide range of model and palaeo-proxy reconstruction approaches. While some studies indicated an abrupt collapse of vegetation at the end of the AHP, others suggested a gradual decline. Claussen et al. (2013) introduced a new aspect in the discussion, proposing that plant diversity in terms of moisture requirements could affect the strength of climate-vegetation feedback. In a conceptual model study, the authors illustrated that high plant diversity could stabilize an ecosystem, whereas a reduction in plant diversity might allow for an abrupt regime shift under gradually changing environmental conditions. In the light of recently published pollen data and the current state of ecological literature, the conceptual model by Claussen et al. (2013) reproduces the main features of different plant types interacting together with climate, but it does not capture the reconstructed diversity of AHP vegetation. Especially tropical gallery forest taxa, indirectly linked to local precipitation, are not appropriately represented. With a new model version adjusted to AHP vegetation, we can simulate a diverse mosaic-like environment as reconstructed from pollen, and we observe a stabilizing effect of high functional diversity on vegetation cover and precipitation. Sensitivity studies with different combinations of plant types highlight the importance of plant composition on system stability, and the stabilizing or destabilizing potential a single plant type may inherit. The model's simplicity limits its application; however, it provides a useful tool to study the roles of real plant types in an ecosystem and their combined climate-vegetation feedback under changing precipitation regimes.

  12. Tubulin-based polymorphism (TBP): a new tool, based on functionally relevant sequences, to assess genetic diversity in plant species.

    PubMed

    Bardini, Mauro; Lee, David; Donini, Paolo; Mariani, Anna; Gianì, Silvia; Toschi, Marcello; Lowe, Chris; Breviario, Diego

    2004-04-01

    TBP (tubulin-based polymorphism) is a new molecular marker based tool that relies on the presence of intron-specific DNA polymorphisms of the plant beta-tubulin gene family. The multifunctional and essential role of the tubulin proteins is reflected in the conservation of regions within their primary amino acid sequence. The ubiquitous nature of this gene family can be exploited using primers that amplify the first intron of different beta-tubulin isotypes, revealing specific fingerprints. The method is rapid, simple, and reliable and does not require preliminary sequence information of the plant genome of interest. The ability of TBP to discriminate between accessions and species in oilseed rape, coffee, and lotus is shown. In all cases, TBP was able to detect specific genetic polymorphisms in the context of a simplified and readily appreciable pattern of DNA amplification. The application of TBP for assessing genetic diversity and genome origins in disseminated plant landraces rather than in highly inbred cultivated species is also discussed. PMID:15060580

  13. Pyrodiversity begets plant-pollinator community diversity.

    PubMed

    Ponisio, Lauren C; Wilkin, Kate; M'Gonigle, Leithen K; Kulhanek, Kelly; Cook, Lindsay; Thorp, Robbin; Griswold, Terry; Kremen, Claire

    2016-05-01

    Fire has a major impact on the structure and function of many ecosystems globally. Pyrodiversity, the diversity of fires within a region (where diversity is based on fire characteristics such as extent, severity, and frequency), has been hypothesized to promote biodiversity, but changing climate and land management practices have eroded pyrodiversity. To assess whether changes in pyrodiversity will have impacts on ecological communities, we must first understand the mechanisms that might enable pyrodiversity to sustain biodiversity, and how such changes might interact with other disturbances such as drought. Focusing on plant-pollinator communities in mixed-conifer forest with frequent fire in Yosemite National Park, California, we examine how pyrodiversity, combined with drought intensity, influences those communities. We find that pyrodiversity is positively related to the richness of the pollinators, flowering plants, and plant-pollinator interactions. On average, a 5% increase in pyrodiversity led to the gain of approximately one pollinator and one flowering plant species and nearly two interactions. We also find that a diversity of fire characteristics contributes to the spatial heterogeneity (β-diversity) of plant and pollinator communities. Lastly, we find evidence that fire diversity buffers pollinator communities against the effects of drought-induced floral resource scarcity. Fire diversity is thus important for the maintenance of flowering plant and pollinator diversity and predicted shifts in fire regimes to include less pyrodiversity compounded with increasing drought occurrence will negatively influence the richness of these communities in this and other forested ecosystems. In addition, lower heterogeneity of fire severity may act to reduce spatial turnover of plant-pollinator communities. The heterogeneity of community composition is a primary determinant of the total species diversity present in a landscape, and thus, lower pyrodiversity may negatively affect the richness of plant-pollinator communities across large spatial scales. PMID:26929389

  14. The influence of linear elements on plant species diversity of Mediterranean rural landscapes: assessment of different indices and statistical approaches.

    PubMed

    García del Barrio, J M; Ortega, M; Vázquez De la Cueva, A; Elena-Rosselló, R

    2006-08-01

    This paper mainly aims to study the linear element influence on the estimation of vascular plant species diversity in five Mediterranean landscapes modeled as land cover patch mosaics. These landscapes have several core habitats and a different set of linear elements--habitat edges or ecotones, roads or railways, rivers, streams and hedgerows on farm land--whose plant composition were examined. Secondly, it aims to check plant diversity estimation in Mediterranean landscapes using parametric and non-parametric procedures, with two indices: Species richness and Shannon index. Land cover types and landscape linear elements were identified from aerial photographs. Their spatial information was processed using GIS techniques. Field plots were selected using a stratified sampling design according to relieve and tree density of each habitat type. A 50x20 m2 multi-scale sampling plot was designed for the core habitats and across the main landscape linear elements. Richness and diversity of plant species were estimated by comparing the observed field data to ICE (Incidence-based Coverage Estimator) and ACE (Abundance-based Coverage Estimator) non-parametric estimators. The species density, percentage of unique species, and alpha diversity per plot were significantly higher (p < 0.05) in linear elements than in core habitats. ICE estimate of number of species was 32% higher than of ACE estimate, which did not differ significantly from the observed values. Accumulated species richness in core habitats together with linear elements, were significantly higher than those recorded only in the core habitats in all the landscapes. Conversely, Shannon diversity index did not show significant differences. PMID:16763745

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

    PubMed

    Waldrop, Mark P; Zak, Donald R; Blackwood, Christopher B; Curtis, Casey D; Tilman, David

    2006-10-01

    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. PMID:16972876

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

    PubMed

    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. PMID:25426856

  17. Curvilinear Effects of Invasive Plants on Plant Diversity: Plant Community Invaded by Sphagneticola trilobata

    PubMed Central

    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. PMID:25426856

  18. Diversity protects plant communities against generalist molluscan herbivores

    PubMed Central

    Fabian, Yvonne; Sandau, Nadine; Bruggisser, Odile T; Kehrli, Patrik; Aebi, Alexandre; Rohr, Rudolf P; Naisbit, Russell E; Bersier, Louis-Félix

    2012-01-01

    Wildflower strips are used to increase natural enemies of crop pests and to conserve insect diversity on farmland. Mollusks, especially slugs, can affect the vegetation development in these strips considerably. Although recent theoretical work suggests that more diverse plant communities will exhibit greater resistance against herbivore pressure, empirical studies are scarce. We conducted a semi-natural experiment in wildflower strips, manipulating trophic structure (reduction in herbivorous mollusks and reduction in major predators) and plant diversity (2, 6, 12, 20 and 24 sown species). This design allowed us to assess the effect of plant diversity, biomass and composition on mollusks, and vice versa, the effect of mollusc abundance on vegetation. Seven species of mollusks were found in the strips, with the slugs Arion lusitanicus, Deroceras reticulatum and Deroceras panormitanum being most frequent. We found a negative relationship between plant diversity and mollusk abundance, which was due predominantly to a decrease in the agricultural pest species A. lusitanicus. These results are consistent with the hypothesis that plant diversity can reduce the impact of herbivores. However, plant identity also had an effect on mollusks, and accounted for a much larger fraction of the variation in mollusk communities than biodiversity effects. While overall plant diversity decreased during the 3 years of the study, in the final year the highest plant diversity was found in the plots where mollusk populations were experimentally reduced. We conclude that selective feeding by generalist herbivores leads to changes in plant community composition and hence reduced plant diversity. Our results highlight the importance of plant biodiversity as protection against generalist herbivores, which if abundant can in the long term negatively impact plant diversity, driving the system along a “low plant diversity – high mollusk abundance” trajectory. PMID:23145332

  19. How does pedogenesis drive plant diversity?

    USGS Publications Warehouse

    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. How does pedogenesis drive plant diversity?

    PubMed

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

    2013-06-01

    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. PMID:23561322

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

    PubMed

    Crawford, Kerri M; Rudgers, Jennifer A

    2013-05-01

    Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species diversity and genetic diversity interact to influence community structure may be critically important for predicting the consequences of biodiversity loss. PMID:23858643

  2. Rapid plant diversity assessment using a pixel nested plot design: A case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA

    USGS Publications Warehouse

    Kalkhan, M.A.; Stafford, E.J.; Stohlgren, T.J.

    2007-01-01

    Geospatial statistical modelling and thematic maps have recently emerged as effective tools for the management of natural areas at the landscape scale. Traditional methods for the collection of field data pertaining to questions of landscape were developed without consideration for the parameters of these applications. We introduce an alternative field sampling design based on smaller unbiased random plot and subplot locations called the pixel nested plot (PNP). We demonstrate the applicability of the PNP design of 15 m x 15 m to assess patterns of plant diversity and species richness across the landscape at Rocky Mountain National Park (RMNP), Colorado, USA in a time (cost)-efficient manner for field data collection. Our results produced comparable results to a previous study in the Beaver Meadow study (BMS) area within RMNP, where there was a demonstrated focus of plant diversity. Our study used the smaller PNP sampling design for field data collection which could be linked to geospatial information data and could be used for landscape-scale analyses and assessment applications. In 2003, we established 61 PNP in the eastern region of RMNP. We present a comparison between this approach using a sub-sample of 19 PNP from this data set and 20 of Modified Whittaker nested plots (MWNP) of 20 m x 50 m that were collected in the BMS area. The PNP captured 266 unique plant species while the MWNP captured 275 unique species. Based on a comparison of PNP and MWNP in the Beaver Meadows area, RMNP, the PNP required less time and area sampled to achieve a similar number of species sampled. Using the PNP approach for data collection can facilitate the ecological monitoring of these vulnerable areas at the landscape scale in a time- and therefore cost-effective manner. ?? 2007 The Authors.

  3. The Choice of PCR Primers Has Great Impact on Assessments of Bacterial Community Diversity and Dynamics in a Wastewater Treatment Plant

    PubMed Central

    Fredriksson, Nils Johan; Hermansson, Malte; Wilén, Britt-Marie

    2013-01-01

    Assessments of bacterial community diversity and dynamics are fundamental for the understanding of microbial ecology as well as biotechnological applications. We show that the choice of PCR primers has great impact on the results of analyses of diversity and dynamics using gene libraries and DNA fingerprinting. Two universal primer pairs targeting the 16S rRNA gene, 27F&1492R and 63F&M1387R, were compared and evaluated by analyzing the bacterial community in the activated sludge of a large-scale wastewater treatment plant. The two primer pairs targeted distinct parts of the bacterial community, none encompassing the other, both with similar richness. Had only one primer pair been used, very different conclusions had been drawn regarding dominant phylogenetic and putative functional groups. With 27F&1492R, Betaproteobacteria would have been determined to be the dominating taxa while 63F&M1387R would have described Alphaproteobacteria as the most common taxa. Microscopy and fluorescence in situ hybridization analysis showed that both Alphaproteobacteria and Betaproteobacteria were abundant in the activated sludge, confirming that the two primer pairs target two different fractions of the bacterial community. Furthermore, terminal restriction fragment polymorphism analyses of a series of four activated sludge samples showed that the two primer pairs would have resulted in different conclusions about community stability and the factors contributing to changes in community composition. In conclusion, different PCR primer pairs, although considered universal, target different ranges of bacteria and will thus show the diversity and dynamics of different fractions of the bacterial community in the analyzed sample. We also show that while a database search can serve as an indicator of how universal a primer pair is, an experimental assessment is necessary to evaluate the suitability for a specific environmental sample. PMID:24098498

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

    EPA Science Inventory

    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, ...

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

    PubMed Central

    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

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

    PubMed

    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 diversity can act as insurance to sustain plant productivity under changing environmental conditions. PMID:21797158

  7. A hierarchical perspective of plant diversity

    USGS Publications Warehouse

    Sarr, Daniel; Hibbs, D.E.; Huston, M.

    2005-01-01

    Predictive models of plant diversity have typically focused on either a landscapea??s capacity for richness (equilibrium models), or on the processes that regulate competitive exclusion, and thus allow species to coexist (nonequilibrium models). Here, we review the concepts and purposes of a hierarchical, multiscale model of the controls of plant diversity that incorporates the equilibrium model of climatic favorability at macroscales, nonequilibrium models of competition at microscales, and a mixed model emphasizing environmental heterogeneity at mesoscales. We evaluate the conceptual model using published data from three spatially nested datasets: (1) a macroscale analysis of ecoregions in the continental and western U.S.; (2) a mesoscale study in California; and (3) a microscale study in the Siskiyou Mountains of Oregon and California. At the macroscale (areas from 3889 km2 to 638,300 km2), climate (actual evaporation) was a strong predictor of tree diversity (R2 = 0.80), as predicted by the conceptual model, but area was a better predictor for vascular plant diversity overall (R2 = 0.38), which suggests different types of plants differ in their sensitivity to climatic controls. At mesoscales (areas from 1111 km2 to 15,833 km2 ), climate was still an important predictor of richness (R2 = 0.52), but, as expected, topographic heterogeneity explained an important share of the variance (R2 = 0.19), showed positive correlations with diversity of trees, shrubs, and annual and perennial herbs, and was the primary predictor of shrub and annual plant species richness. At microscales (0.1 ha plots), spatial patterns of diversity showed a clear unimodal pattern along a climatea??driven productivity gradient and a negative relationship with soil fertility. The strong decline in understory and total diversity at the most productive sites suggests that competitive controls, as predicted, can override climatic controls at this scale. We conclude that this hierarchical, multiscale model provides a sound basis to understand and analyze plant species diversity. Specifically, future research should employ the principles in this paper to explore climatic controls on species richness of different life forms, better quantify environmental heterogeneity in landscapes, and analyze how these largea??scale factors interact with local nonequilibrium dynamics to maintain plant diversity.

  8. Reconciling Harvest Intensity and Plant Diversity in Boreal Ecosystems: Does Intensification Influence Understory Plant Diversity?

    NASA Astrophysics Data System (ADS)

    Kershaw, H. Maureen; Morris, Dave M.; Fleming, Robert L.; Luckai, Nancy J.

    2015-11-01

    Overall demand for forest products in the boreal forest is increasing to supply growing bio-energy demands in addition to traditional forest products. As a result, there is a need to refine current forest policies to reconcile production and ecosystem function within the context of ecologically sustainable management. This study assessed understory plants' richness, evenness, and diversity in six harvested boreal black spruce-dominated stands situated on loam, sand, and peat site types 15 years after the application of four harvest treatments of increasing biomass removals. Treatments included uncut, stem-only harvest, full-tree harvest, and full-tree harvest + blading of O horizon. Following canopy removal, species richness and diversity (Shannon's and Simpson's indices) increased on all soil types. The more than doubling of slash loading on the stem-only treatment plots compared to the full-tree plots led to significantly lower species diversity on loam sites; however, the reverse was observed on peat sites where the slash provided warmer, drier microsites facilitating the establishment of a broader array of species. Preexisting ericaceous shrub and sphagnum components continued to dominate on the peat sites. Compositional shifts were most evident for the full-tree + bladed treatment on all soil types, with increases in herbaceous cover including ruderal species. The results suggest that the intensification of harvesting on plant diversity varies with soil type, and these differential results should be considered in the refinement of forest biomass-harvesting guidelines to ensure ecological sustainability and biodiversity conservation over a broad suite of soil types.

  9. Reconciling Harvest Intensity and Plant Diversity in Boreal Ecosystems: Does Intensification Influence Understory Plant Diversity?

    PubMed

    Kershaw, H Maureen; Morris, Dave M; Fleming, Robert L; Luckai, Nancy J

    2015-11-01

    Overall demand for forest products in the boreal forest is increasing to supply growing bio-energy demands in addition to traditional forest products. As a result, there is a need to refine current forest policies to reconcile production and ecosystem function within the context of ecologically sustainable management. This study assessed understory plants' richness, evenness, and diversity in six harvested boreal black spruce-dominated stands situated on loam, sand, and peat site types 15 years after the application of four harvest treatments of increasing biomass removals. Treatments included uncut, stem-only harvest, full-tree harvest, and full-tree harvest + blading of O horizon. Following canopy removal, species richness and diversity (Shannon's and Simpson's indices) increased on all soil types. The more than doubling of slash loading on the stem-only treatment plots compared to the full-tree plots led to significantly lower species diversity on loam sites; however, the reverse was observed on peat sites where the slash provided warmer, drier microsites facilitating the establishment of a broader array of species. Preexisting ericaceous shrub and sphagnum components continued to dominate on the peat sites. Compositional shifts were most evident for the full-tree + bladed treatment on all soil types, with increases in herbaceous cover including ruderal species. The results suggest that the intensification of harvesting on plant diversity varies with soil type, and these differential results should be considered in the refinement of forest biomass-harvesting guidelines to ensure ecological sustainability and biodiversity conservation over a broad suite of soil types. PMID:26092048

  10. Functional and phylogenetic diversity of woody plants drive herbivory in a highly diverse forest

    PubMed Central

    Schuldt, Andreas; Assmann, Thorsten; Bruelheide, Helge; Durka, Walter; Eichenberg, David; Härdtle, Werner; Kröber, Wenzel; Michalski, Stefan G; Purschke, Oliver

    2014-01-01

    Biodiversity loss may alter ecosystem processes, such as herbivory, a key driver of ecological functions in species-rich (sub)tropical forests. However, the mechanisms underlying such biodiversity effects remain poorly explored, as mostly effects of species richness – a very basic biodiversity measure – have been studied. Here, we analyze to what extent the functional and phylogenetic diversity of woody plant communities affect herbivory along a diversity gradient in a subtropical forest.We assessed the relative effects of morphological and chemical leaf traits and of plant phylogenetic diversity on individual-level variation in herbivory of dominant woody plant species across 27 forest stands in south-east China.Individual-level variation in herbivory was best explained by multivariate, community-level diversity of leaf chemical traits, in combination with community-weighted means of single traits and species-specific phylodiversity measures. These findings deviate from those based solely on trait variation within individual species.Our results indicate a strong impact of generalist herbivores and highlight the need to assess food-web specialization to determine the direction of biodiversity effects. With increasing plant species loss, but particularly with the concomitant loss of functional and phylogenetic diversity in these forests, the impact of herbivores will probably decrease – with consequences for the herbivore-mediated regulation of ecosystem functions. PMID:24460549

  11. Plant Functional Diversity and Species Diversity in the Mongolian Steppe

    PubMed Central

    Liu, Guofang; Xie, Xiufang; Ye, Duo; Ye, Xuehua; Tuvshintogtokh, Indree; Mandakh, Bayart; Huang, Zhenying; Dong, Ming

    2013-01-01

    Background The Mongolian steppe is one of the most important grasslands in the world but suffers from aridization and damage from anthropogenic activities. Understanding structure and function of this community is important for the ecological conservation, but has seldom been investigated. Methodology/Principal Findings In this study, a total of 324 quadrats located on the three main types of Mongolian steppes were surveyed. Early-season perennial forbs (37% of total importance value), late-season annual forbs (33%) and late-season perennial forbs (44%) were dominant in meadow, typical and desert steppes, respectively. Species richness, diversity and plant functional type (PFT) richness decreased from the meadow, via typical to desert steppes, but evenness increased; PFT diversity in the desert and meadow steppes was higher than that in typical steppe. However, above-ground net primary productivity (ANPP) was far lower in desert steppe than in the other two steppes. In addition, the slope of the relationship between species richness and PFT richness increased from the meadow, via typical to desert steppes. Similarly, with an increase in species diversity, PFT diversity increased more quickly in both the desert and typical steppes than that in meadow steppe. Random resampling suggested that this coordination was partly due to a sampling effect of diversity. Conclusions/Significance These results indicate that desert steppe should be strictly protected because of its limited functional redundancy, which its ecological functioning is sensitive to species loss. In contrast, despite high potential forage production shared by the meadow and typical steppes, management of these two types of steppes should be different: meadow steppe should be preserved due to its higher conservation value characterized by more species redundancy and higher spatial heterogeneity, while typical steppe could be utilized moderately because its dominant grass genus Stipa is resistant to herbivory and drought. PMID:24116233

  12. An Inventory of Peer Assessment Diversity

    ERIC Educational Resources Information Center

    Gielen, Sarah; Dochy, Filip; Onghena, Patrick

    2011-01-01

    Since Topping published his literature review on peer assessment in 1998, the number of studies on this subject has doubled, if not tripled. However, along with this expansion, the diversity of peer assessment applications increased equally fast. Based on recent literature, this contribution focuses specifically on the diversity that has come to…

  13. Local Plant Diversity Across Multiple Habitats Supports a Diverse Wild Bee Community in Pennsylvania Apple Orchards.

    PubMed

    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. PMID:26385933

  14. Diverse urban plantings managed with sufficient resource availability can increase plant productivity and arthropod diversity.

    PubMed

    Muller, Jonathon N; Loh, Susan; Braggion, Ligia; Cameron, Stephen; Firn, Jennifer L

    2014-01-01

    Buildings structures and surfaces are explicitly being used to grow plants, and these "urban plantings" are generally designed for aesthetic value. Urban plantings also have the potential to contribute significant "ecological values" by increasing urban habitat for animals such as arthropods and by increasing plant productivity. In this study, we evaluated how the provision of these additional ecological values is affected by plant species richness; the availability of essential resources for plants, such as water, light, space; and soil characteristics. We sampled 33 plantings located on the exterior of three buildings in the urban center of Brisbane, Australia (subtropical climatic region) over 2, 6 week sampling periods characterized by different temperature and rainfall conditions. Plant cover was estimated as a surrogate for productivity as destructive sampling of biomass was not possible. We measured weekly light levels (photosynthetically active radiation), plant CO2 assimilation, soil CO2 efflux, and arthropod diversity. Differences in plant cover were best explained by a three-way interaction of plant species richness, management water regime and sampling period. As the richness of plant species increased in a planter, productivity and total arthropod richness also increased significantly-likely due to greater habitat heterogeneity and quality. Overall we found urban plantings can provide additional ecological values if essential resources are maintained within a planter such as water, light and soil temperature. Diverse urban plantings that are managed with these principles in mind can contribute to the attraction of diverse arthropod communities, and lead to increased plant productivity within a dense urban context. PMID:25400642

  15. Diverse urban plantings managed with sufficient resource availability can increase plant productivity and arthropod diversity

    PubMed Central

    Muller, Jonathon N.; Loh, Susan; Braggion, Ligia; Cameron, Stephen; Firn, Jennifer L.

    2014-01-01

    Buildings structures and surfaces are explicitly being used to grow plants, and these “urban plantings” are generally designed for aesthetic value. Urban plantings also have the potential to contribute significant “ecological values” by increasing urban habitat for animals such as arthropods and by increasing plant productivity. In this study, we evaluated how the provision of these additional ecological values is affected by plant species richness; the availability of essential resources for plants, such as water, light, space; and soil characteristics. We sampled 33 plantings located on the exterior of three buildings in the urban center of Brisbane, Australia (subtropical climatic region) over 2, 6 week sampling periods characterized by different temperature and rainfall conditions. Plant cover was estimated as a surrogate for productivity as destructive sampling of biomass was not possible. We measured weekly light levels (photosynthetically active radiation), plant CO2 assimilation, soil CO2 efflux, and arthropod diversity. Differences in plant cover were best explained by a three-way interaction of plant species richness, management water regime and sampling period. As the richness of plant species increased in a planter, productivity and total arthropod richness also increased significantly—likely due to greater habitat heterogeneity and quality. Overall we found urban plantings can provide additional ecological values if essential resources are maintained within a planter such as water, light and soil temperature. Diverse urban plantings that are managed with these principles in mind can contribute to the attraction of diverse arthropod communities, and lead to increased plant productivity within a dense urban context. PMID:25400642

  16. Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide

    USGS Publications Warehouse

    Prober, Suzanne M.; Leff, Jonathan W.; Bates, Scott T.; Borer, Elizabeth T.; Firn, Jennifer; Harpole, W. Stanley; Lind, Eric M.; Seabloom, Eric W.; Adler, Peter B.; Bakker, Jonathan D.; Cleland, Elsa E.; DeCrappeo, Nicole; DeLorenze, Elizabeth; Hagenah, Nicole; Hautier, Yann; Hofmockel, Kirsten S.; Kirkman, Kevin P.; Knops, Johannes M. H.; La Pierre, Kimberly J.; MacDougall, Andrew S.; McCulley, Rebecca L.; Mitchell, Charles E.; Risch, Anita C.; Schuetz, Martin; Stevens, Carly J.; Williams, Ryan J.; Fierer, Noah

    2015-01-01

    Aboveground–belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m2 plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

  17. Assessing bacterial diversity in a seawater-processing wastewater treatment plant by 454-pyrosequencing of the 16S rRNA and amoA genes

    PubMed Central

    Sánchez, Olga; Ferrera, Isabel; González, Jose M; Mas, Jordi

    2013-01-01

    Summary The bacterial community composition of activated sludge from a wastewater treatment plant (Almería, Spain) with the particularity of using seawater was investigated by applying 454-pyrosequencing. The results showed that Deinococcus-Thermus, Proteobacteria, Chloroflexi and Bacteroidetes were the most abundant retrieved sequences, while other groups, such as Actinobacteria, Chlorobi, Deferribacteres, Firmicutes, Planctomycetes, Spirochaetes and Verrumicrobia were reported at lower proportions. Rarefaction analysis showed that very likely the diversity is higher than what could be described despite most of the unknown microorganisms probably correspond to rare diversity. Furthermore, the majority of taxa could not be classified at the genus level and likely represent novel members of these groups. Additionally, the nitrifiers in the sludge were characterized by pyrosequencing the amoA gene. In contrast, the nitrifying bacterial community, dominated by the genera Nitrosomonas, showed a low diversity and rarefaction curves exhibited saturation. These results suggest that only a few populations of low abundant but specialized bacteria are responsible for removal of ammonia in these saline wastewater systems. PMID:23574645

  18. The emergence of diversity in plant communities.

    PubMed

    Levin, S A; Muller-Landau, H C

    2000-01-01

    The diversity of functional forms and strategies in plant communities is essential to the maintenance of the services that ecosystems provide humanity, and ultimately to the homeostasis of the biosphere. This diversity emerges from evolutionary forces operating at lower levels; these exploit the opportunities for specialization presented by exogenous and endogenous spatial and temporal heterogeneity. Two major theoretical approaches have been taken to understand how strategies arise and are maintained: optimization models, which consider the fitnesses of types in isolation, and game-theoretic methods, which take frequency dependence into account. The game-theoretic approach is more powerful, but also more challenging to apply. For some relatively simple problems in the study of biodiversity, we show how the game-theoretic formulation can be translated into an equivalent problem in optimization. More generally, however, new techniques will be needed to explore the dynamics of multiple coexisting types and strategies. PMID:10742918

  19. Diverse pollinator communities enhance plant reproductive success

    PubMed Central

    Albrecht, Matthias; Schmid, Bernhard; Hautier, Yann; Müller, Christine B.

    2012-01-01

    Understanding the functional consequences of biodiversity loss is a major goal of ecology. Animal-mediated pollination is an essential ecosystem function and service provided to mankind. However, little is known how pollinator diversity could affect pollination services. Using a substitutive design, we experimentally manipulated functional group (FG) and species richness of pollinator communities to investigate their consequences on the reproductive success of an obligate out-crossing model plant species, Raphanus sativus. Both fruit and seed set increased with pollinator FG richness. Furthermore, seed set increased with species richness in pollinator communities composed of a single FG. However, in multiple-FG communities, highest species richness resulted in slightly reduced pollination services compared with intermediate species richness. Our analysis indicates that the presence of social bees, which showed roughly four times higher visitation rates than solitary bees or hoverflies, was an important factor contributing to the positive pollinator diversity–pollination service relationship, in particular, for fruit set. Visitation rate at different daytimes, and less so among flower heights, varied among social bees, solitary bees and hoverflies, indicating a niche complementarity among these pollinator groups. Our study demonstrates enhanced pollination services of diverse pollinator communities at the plant population level and suggests that both the niche complementarity and the presence of specific taxa in a pollinator community drive this positive relationship. PMID:23034701

  20. Straight Talk about Cognitive Assessment and Diversity.

    ERIC Educational Resources Information Center

    Frisby, Craig L.

    1999-01-01

    Discusses three reasons explaining heightened interest in alternative assessment in the context of diversity issues in school psychology: inadequacy of traditional test use with language populations for whom tests were not designed; the hope that alternative assessment will eliminate, reduce, or camouflage average score differences between…

  1. Species interaction mechanisms maintain grassland plant species diversity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Theory has outpaced empirical research in pursuit of identifying mechanisms maintaining species diversity. Here we demonstrate how data from diversity-ecosystem functioning experiments can be used to test maintenance of diversity theory. We predict that grassland plant diversity can be maintained by...

  2. PLANT DIVERSITY OF WESTERN CHITWAN FLORISTIC APPROACH

    PubMed Central

    Dangol, D. R.; Shivakoti, G. P.

    2012-01-01

    This paper identifies and documents the plant biodiversity of western Chitwan, Nepal. Specifically, our attention was focussed on the plants of forests, grasslands and common lands based on our “Reciprocal Relation of Population and Environment Study Project” conducted during January-April 1996. This species-diversity of trees, shrubs and herbaceous flora was recorded from 117, 117, and 1049 sampling quadrats of 10×10, 3×3 and 1×1 m2, respectively. The flora of our study plots contains 236 species that belong to 191 genera and 66 families. Of 236 species of plants, 119, 113, 59, 35 and 119 species were recorded from Tikauli forest, National Park forest, forests along the Narayani river, grasslands of National Park and common lands of the western Chitwan, respectively. Dicotyledons represent 184 (77.97%) species of the total flora species followed by monocotyledons (46 spp., 19.49%) and ferns (6 spp., 2.54%), respectively. The five largest families are Leguminosae (38 spp.), Poaceae (27 spp.), Asteraceae (22 spp.), Rubiaceae (10 spp.), and Scrophulariaceae (9 spp.). Hedyotis, Grewia and Lindernia, each with 4 spp., are the most speciose genera in the flora. PMID:22899874

  3. Decomposer diversity and identity influence plant diversity effects on ecosystem functioning.

    PubMed

    Eisenhauer, Nico; Reich, Peter B; Isbell, Forest

    2012-10-01

    Plant productivity and other ecosystem functions often increase with plant diversity at a local scale. Alongside various plant-centered explanations for this pattern, there is accumulating evidence that multi-trophic interactions shape this relationship. Here, we investigated for the first time if plant diversity effects on ecosystem functioning are mediated or driven by decomposer animal diversity and identity using a double-diversity microcosm experiment. We show that many ecosystem processes and ecosystem multifunctionality (herbaceous shoot biomass production, litter removal, and N uptake) were affected by both plant and decomposer diversity, with ecosystem process rates often being maximal at intermediate to high plant and decomposer diversity and minimal at both low plant and decomposer diversity. Decomposers relaxed interspecific plant competition by enlarging chemical (increased N uptake and surface-litter decomposition) and spatial (increasing deep-root biomass) habitat space and by promoting plant complementarity. Anecic earthworms and isopods functioned as key decomposers; although decomposer diversity effects did not solely rely on these two decomposer species, positive plant net biodiversity and complementarity effects only occurred in the absence of isopods and the presence of anecic earthworms. Using a structural equation model, we explained 76% of the variance in plant complementarity, identified direct and indirect effect paths, and showed that the presence of key decomposers accounted for approximately three-quarters of the explained variance. We conclude that decomposer animals have been underappreciated as contributing agents of plant diversity-ecosystem functioning relationships. Elevated decomposer performance at high plant diversity found in previous experiments likely positively feeds back to plant performance, thus contributing to the positive relationship between plant diversity and ecosystem functioning. PMID:23185884

  4. Environmental correlates of plant diversity in Korean temperate forests

    NASA Astrophysics Data System (ADS)

    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.

  5. Exotic plant species invade hot spots of native plant diversity

    USGS Publications Warehouse

    Stohlgren, T.J.; Binkley, D.; Chong, G.W.; Kalkhan, M.A.; Schell, L.D.; Bull, K.A.; Otsuki, Y.; Newman, G.; Bashkin, M.; Yowhan, S.

    1999-01-01

    Some theories and experimental studies suggest that areas of low plant species richness may be invaded more easily than areas of high plant species richness. We gathered nested-scale vegetation data on plant species richness, foliar cover, and frequency from 200 1-m2 subplots (20 1000-m2 modified-Whittaker plots) in the Colorado Rockies (USA), and 160 1-m2 subplots (16 1000-m2 plots) in the Central Grasslands in Colorado, Wyoming, South Dakota, and Minnesota (USA) to test the generality of this paradigm. At the 1-m2 scale, the paradigm was supported in four prairie types in the Central Grasslands, where exotic species richness declined with increasing plant species richness and cover. At the 1-m2 scale, five forest and meadow vegetation types in the Colorado Rockies contradicted the paradigm; exotic species richness increased with native-plant species richness and foliar cover. At the 1000-m2 plot scale (among vegetation types), 83% of the variance in exotic species richness in the Central Grasslands was explained by the total percentage of nitrogen in the soil and the cover of native plant species. In the Colorado Rockies, 69% of the variance in exotic species richness in 1000-m2 plots was explained by the number of native plant species and the total percentage of soil carbon. At landscape and biome scales, exotic species primarily invaded areas of high species richness in the four Central Grasslands sites and in the five Colorado Rockies vegetation types. For the nine vegetation types in both biomes, exotic species cover was positively correlated with mean foliar cover, mean soil percentage N, and the total number of exotic species. These patterns of invasibility depend on spatial scale, biome and vegetation type, spatial autocorrelation effects, availability of resources, and species-specific responses to grazing and other disturbances. We conclude that: (1) sites high in herbaceous foliar cover and soil fertility, and hot spots of plant diversity (and biodiversity), are invasible in many landscapes; and (2) this pattern may be more closely related to the degree resources are available in native plant communities, independent of species richness. Exotic plant invasions in rare habitats and distinctive plant communities pose a significant challenge to land managers and conservation biologists.

  6. Plant diversity increases soil microbial activity and soil carbon storage.

    PubMed

    Lange, Markus; Eisenhauer, Nico; Sierra, Carlos A; Bessler, Holger; Engels, Christoph; Griffiths, Robert I; Mellado-Vázquez, Perla G; Malik, Ashish A; Roy, Jacques; Scheu, Stefan; Steinbeiss, Sibylle; Thomson, Bruce C; Trumbore, Susan E; Gleixner, Gerd

    2015-01-01

    Plant diversity strongly influences ecosystem functions and services, such as soil carbon storage. However, the mechanisms underlying the positive plant diversity effects on soil carbon storage are poorly understood. We explored this relationship using long-term data from a grassland biodiversity experiment (The Jena Experiment) and radiocarbon ((14)C) modelling. Here we show that higher plant diversity increases rhizosphere carbon inputs into the microbial community resulting in both increased microbial activity and carbon storage. Increases in soil carbon were related to the enhanced accumulation of recently fixed carbon in high-diversity plots, while plant diversity had less pronounced effects on the decomposition rate of existing carbon. The present study shows that elevated carbon storage at high plant diversity is a direct function of the soil microbial community, indicating that the increase in carbon storage is mainly limited by the integration of new carbon into soil and less by the decomposition of existing soil carbon. PMID:25848862

  7. Opposing phylogenetic diversity gradients of plant and soil bacterial communities.

    PubMed

    Goberna, Marta; Navarro-Cano, Jose A; Verdú, Miguel

    2016-02-24

    Plants and soil microbes show parallel patterns of species-level diversity. Diverse plant communities release a wider range of organics that are consumed by more microbial species. We speculated, however, that diversity metrics accounting for the evolutionary distance across community members would reveal opposing patterns between plant and soil bacterial phylogenetic diversity. Plant phylogenetic diversity enhances plant productivity and thus expectedly soil fertility. This, in turn, might reduce bacterial phylogenetic diversity by favouring one (or a few) competitive bacterial clade. We collected topsoils in 15 semi-arid plant patches and adjacent low-cover areas configuring a plant phylodiversity gradient, pyrosequenced the 16S rRNA gene to identify bacterial taxa and analysed soil fertility parameters. Structural equation modelling showed positive effects of both plant richness and phylogenetic diversity on soil fertility. Fertility increased bacterial richness but reduced bacterial phylogenetic diversity. This might be attributed to the competitive dominance of a lineage based on its high relative fitness. This suggests biotic interactions as determinants of the soil bacterial community assembly, while emphasizing the need to use phylogeny-informed metrics to tease apart the processes underlying the patterns of diversity. PMID:26888037

  8. Assessing Nutritional Diversity of Cropping Systems in African Villages

    PubMed Central

    DeClerck, Fabrice; Diru, Willy; Fanzo, Jessica; Gaynor, Kaitlyn; Lambrecht, Isabel; Mudiope, Joseph; Mutuo, Patrick K.; Nkhoma, Phelire; Siriri, David; Sullivan, Clare; Palm, Cheryl A.

    2011-01-01

    Background In Sub-Saharan Africa, 40% of children under five years in age are chronically undernourished. As new investments and attention galvanize action on African agriculture to reduce hunger, there is an urgent need for metrics that monitor agricultural progress beyond calories produced per capita and address nutritional diversity essential for human health. In this study we demonstrate how an ecological tool, functional diversity (FD), has potential to address this need and provide new insights on nutritional diversity of cropping systems in rural Africa. Methods and Findings Data on edible plant species diversity, food security and diet diversity were collected for 170 farms in three rural settings in Sub-Saharan Africa. Nutritional FD metrics were calculated based on farm species composition and species nutritional composition. Iron and vitamin A deficiency were determined from blood samples of 90 adult women. Nutritional FD metrics summarized the diversity of nutrients provided by the farm and showed variability between farms and villages. Regression of nutritional FD against species richness and expected FD enabled identification of key species that add nutrient diversity to the system and assessed the degree of redundancy for nutrient traits. Nutritional FD analysis demonstrated that depending on the original composition of species on farm or village, adding or removing individual species can have radically different outcomes for nutritional diversity. While correlations between nutritional FD, food and nutrition indicators were not significant at household level, associations between these variables were observed at village level. Conclusion This study provides novel metrics to address nutritional diversity in farming systems and examples of how these metrics can help guide agricultural interventions towards adequate nutrient diversity. New hypotheses on the link between agro-diversity, food security and human nutrition are generated and strategies for future research are suggested calling for integration of agriculture, ecology, nutrition, and socio-economics. PMID:21698127

  9. Microbes on mountainsides: Contrasting elevational patterns of bacterial and plant diversity

    PubMed Central

    Bryant, Jessica A.; Lamanna, Christine; Morlon, Hélène; Kerkhoff, Andrew J.; Enquist, Brian J.; Green, Jessica L.

    2008-01-01

    The study of elevational diversity gradients dates back to the foundation of biogeography. Although elevational patterns of plant and animal diversity have been studied for centuries, such patterns have not been reported for microorganisms and remain poorly understood. Here, in an effort to assess the generality of elevational diversity patterns, we examined soil bacterial and plant diversity along an elevation gradient. To gain insight into the forces that structure these patterns, we adopted a multifaceted approach to incorporate information about the structure, diversity, and spatial turnover of montane communities in a phylogenetic context. We found that observed patterns of plant and bacterial diversity were fundamentally different. While bacterial taxon richness and phylogenetic diversity decreased monotonically from the lowest to highest elevations, plants followed a unimodal pattern, with a peak in richness and phylogenetic diversity at mid-elevations. At all elevations bacterial communities had a tendency to be phylogenetically clustered, containing closely related taxa. In contrast, plant communities did not exhibit a uniform phylogenetic structure across the gradient: they became more overdispersed with increasing elevation, containing distantly related taxa. Finally, a metric of phylogenetic beta-diversity showed that bacterial lineages were not randomly distributed, but rather exhibited significant spatial structure across the gradient, whereas plant lineages did not exhibit a significant phylogenetic signal. Quantifying the influence of sample scale in intertaxonomic comparisons remains a challenge. Nevertheless, our findings suggest that the forces structuring microorganism and macroorganism communities along elevational gradients differ. PMID:18695215

  10. Synthesis and assessment of date palm genetic diversity studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A thorough assessment of genetic diversity and population differentiation of Phoenix dactylifera are critical for its dynamic conservation and sustainable utilization of its genetic diversity. Estimates of genetic diversity based on phenotypic, biochemical and molecular markers; and fruit quality tr...

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

    NASA Astrophysics Data System (ADS)

    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 to have major feedbacks on plant community productivity and composition.

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

    PubMed Central

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

    2014-01-01

    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. PMID:24718763

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

    PubMed

    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. PMID:24718763

  14. Pathogens and insect herbivores drive rainforest plant diversity and composition.

    PubMed

    Bagchi, Robert; Gallery, Rachel E; Gripenberg, Sofia; Gurr, Sarah J; Narayan, Lakshmi; Addis, Claire E; Freckleton, Robert P; Lewis, Owen T

    2014-02-01

    Tropical forests are important reservoirs of biodiversity, but the processes that maintain this diversity remain poorly understood. The Janzen-Connell hypothesis suggests that specialized natural enemies such as insect herbivores and fungal pathogens maintain high diversity by elevating mortality when plant species occur at high density (negative density dependence; NDD). NDD has been detected widely in tropical forests, but the prediction that NDD caused by insects and pathogens has a community-wide role in maintaining tropical plant diversity remains untested. We show experimentally that changes in plant diversity and species composition are caused by fungal pathogens and insect herbivores. Effective plant species richness increased across the seed-to-seedling transition, corresponding to large changes in species composition. Treating seeds and young seedlings with fungicides significantly reduced the diversity of the seedling assemblage, consistent with the Janzen-Connell hypothesis. Although suppressing insect herbivores using insecticides did not alter species diversity, it greatly increased seedling recruitment and caused a marked shift in seedling species composition. Overall, seedling recruitment was significantly reduced at high conspecific seed densities and this NDD was greatest for the species that were most abundant as seeds. Suppressing fungi reduced the negative effects of density on recruitment, confirming that the diversity-enhancing effect of fungi is mediated by NDD. Our study provides an overall test of the Janzen-Connell hypothesis and demonstrates the crucial role that insects and pathogens have both in structuring tropical plant communities and in maintaining their remarkable diversity. PMID:24463522

  15. Endophytic actinobacteria of medicinal plants: diversity and bioactivity.

    PubMed

    Golinska, Patrycja; Wypij, Magdalena; Agarkar, Gauravi; Rathod, Dnyaneshwar; Dahm, Hanna; Rai, Mahendra

    2015-08-01

    Endophytes are the microorganisms that exist inside the plant tissues without having any negative impact on the host plant. Medicinal plants constitute the huge diversity of endophytic actinobacteria of economical importance. These microbes have huge potential to synthesis of numerous novel compounds that can be exploited in pharmaceutical, agricultural and other industries. It is of prime importance to focus the present research on practical utilization of this microbial group in order to find out the solutions to the problems related to health, environment and agriculture. An extensive characterization of diverse population of endophytic actinobacteria associated with medicinal plants can provide a greater insight into the plant-endophyte interactions and evolution of mutualism. In the present review, we have discussed the diversity of endophytic actinobacteria of from medicinal plants their multiple bioactivities. PMID:26093915

  16. Plant-pollinator coextinctions and the loss of plant functional and phylogenetic diversity.

    PubMed

    Vieira, Marcos Costa; Cianciaruso, Marcus Vinicius; Almeida-Neto, Mário

    2013-01-01

    Plant-pollinator coextinctions are likely to become more frequent as habitat alteration and climate change continue to threaten pollinators. The consequences of the resulting collapse of plant communities will depend partly on how quickly plant functional and phylogenetic diversity decline following pollinator extinctions. We investigated the functional and phylogenetic consequences of pollinator extinctions by simulating coextinctions in seven plant-pollinator networks coupled with independent data on plant phylogeny and functional traits. Declines in plant functional diversity were slower than expected under a scenario of random extinctions, while phylogenetic diversity often decreased faster than expected by chance. Our results show that plant functional diversity was relatively robust to plant-pollinator coextinctions, despite the underlying rapid loss of evolutionary history. Thus, our study suggests the possibility of uncoupled responses of functional and phylogenetic diversity to species coextinctions, highlighting the importance of considering both dimensions of biodiversity explicitly in ecological studies and when planning for the conservation of species and interactions. PMID:24312281

  17. Does herbivore diversity depend on plant diversity? The case of California butterflies.

    PubMed

    Hawkins, Bradford A; Porter, Eric E

    2003-01-01

    It is widely believed that the diversity of plants influences the diversity of animals, and this should be particularly true of herbivores. We examine this supposition at a moderate spatial extent by comparing the richness patterns of the 217 butterfly species resident in California to those of plants, including all 5,902 vascular plant species and the 552 species known to be fed on by caterpillars. We also examine the relationships between plant/butterfly richness and 20 environmental variables. We found that although plant and butterfly diversities are positively correlated, multiple regression, path models, and spatial analysis indicate that once primary productivity (estimated by a water-energy variable, actual evapotranspiration) and topographical variability are incorporated into models, neither measure of plant richness has any relationship with butterfly richness. To examine whether butterflies with the most specialized diets follow the pattern found across all butterflies, we repeated the analyses for 37 species of strict monophages and their food plants and found that plant and butterfly richness were similarly weakly associated after incorporating the environmental variables. We condude that plant diversity does not directly influence butterfly diversity but that both are probably responding to similar environmental factors. PMID:12650461

  18. In the footsteps of Vavilov: plant diversity then and now

    Technology Transfer Automated Retrieval System (TEKTRAN)

    N. I. Vavilov’s theories direct present day global activities in plant science, breeding, and conservation. His expeditions around the world located centers of diversity of crop evolution. Vavilov was one of the earliest scientists to realize that wild genetic diversity could be lost, through geneti...

  19. Assessment of Genetic Diversity of Sweet Potato in Puerto Rico

    PubMed Central

    Rodriguez-Bonilla, Lorraine; Cuevas, Hugo E.; Montero-Rojas, Milly; Bird-Pico, Fernando; Luciano-Rosario, Dianiris; Siritunga, Dimuth

    2014-01-01

    Sweet potato (Ipomoea batatas L.) is the seventh most important food crop due to its distinct advantages, such as adaptability to different environmental conditions and high nutritional value. Assessing the genetic diversity of this important crop is necessary due to the constant increase of demand for food and the need for conservation of agricultural and genetic resources. In Puerto Rico (PR), the genetic diversity of sweet potato has been poorly understood, although it has been part of the diet since Pre-Columbus time. Thus, 137 landraces from different localities around PR were collected and subjected to a genetic diversity analysis using 23 SSR-markers. In addition, 8 accessions from a collection grown in Gurabo, PR at the Agricultural Experimental Station (GAES), 10 US commercial cultivars and 12 Puerto Rican accessions from the USDA repository collection were included in this assessment. The results of the analysis of the 23 loci showed 255 alleles in the 167 samples. Observed heterozygosity was high across populations (0.71) while measurements of total heterozygosity revealed a large genetic diversity throughout the population and within populations. UPGMA clustering method revealed two main clusters. Cluster 1 contained 12 PR accessions from the USDA repository collection, while cluster 2 consisted of PR landraces, US commercial cultivars and the PR accessions from GAES. Population structure analysis grouped PR landraces in five groups including four US commercial cultivars. Our study shows the presence of a high level of genetic diversity of sweet potato across PR which can be related to the genetic makeup of sweet potato, human intervention and out-crossing nature of the plant. The history of domestication and dispersal of sweet potato in the Caribbean and the high levels of genetic diversity found through this study makes sweet potato an invaluable resource that needs to be protected and further studied. PMID:25551388

  20. Power Plant Water Intake Assessment.

    ERIC Educational Resources Information Center

    Zeitoun, Ibrahim H.; And Others

    1980-01-01

    In order to adequately assess the impact of power plant cooling water intake on an aquatic ecosystem, total ecosystem effects must be considered, rather than merely numbers of impinged or entrained organisms. (Author/RE)

  1. Plant genotypic diversity reduces the rate of consumer resource utilization

    PubMed Central

    McArt, Scott H.; Thaler, Jennifer S.

    2013-01-01

    While plant species diversity can reduce herbivore densities and herbivory, little is known regarding how plant genotypic diversity alters resource utilization by herbivores. Here, we show that an invasive folivore—the Japanese beetle (Popillia japonica)—increases 28 per cent in abundance, but consumes 24 per cent less foliage in genotypic polycultures compared with monocultures of the common evening primrose (Oenothera biennis). We found strong complementarity for reduced herbivore damage among plant genotypes growing in polycultures and a weak dominance effect of particularly resistant genotypes. Sequential feeding by P. japonica on different genotypes from polycultures resulted in reduced consumption compared with feeding on different plants of the same genotype from monocultures. Thus, diet mixing among plant genotypes reduced herbivore consumption efficiency. Despite positive complementarity driving an increase in fruit production in polycultures, we observed a trade-off between complementarity for increased plant productivity and resistance to herbivory, suggesting costs in the complementary use of resources by plant genotypes may manifest across trophic levels. These results elucidate mechanisms for how plant genotypic diversity simultaneously alters resource utilization by both producers and consumers, and show that population genotypic diversity can increase the resistance of a native plant to an invasive herbivore. PMID:23658201

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

    PubMed Central

    Lekberg, Ylva; Gibbons, Sean M; Rosendahl, Søren; Ramsey, Philip W

    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 not cheatgrass (Bromus tectorum)—support a higher abundance and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) than multi-species native plant communities. The higher AMF richness associated with knapweed and spurge is unlikely due to a co-invasion by AMF, because a separate sampling showed that individual native forbs hosted a similar AMF abundance and richness as exotic forbs. Native grasses associated with fewer AMF taxa, which could explain the reduced AMF richness in native, grass-dominated communities. The three invasive plant species harbored distinct AMF communities, and analyses of co-occurring native and invasive plants indicate that differences were partly driven by the invasive plants and were not the result of pre-invasion conditions. Our results suggest that invasions by mycotrophic plants that replace poorer hosts can increase AMF abundance and richness. The high AMF richness in monodominant plant invasions also indicates that the proposed positive relationship between above and belowground diversity is not always strong. Finally, the disparate responses among exotic plants and consistent results between grasses and forbs suggest that AMF respond more to plant functional group than plant provenance. PMID:23486251

  3. Experimental Manipulation of Grassland Plant Diversity Induces Complex Shifts in Aboveground Arthropod Diversity.

    PubMed

    Hertzog, Lionel R; Meyer, Sebastian T; Weisser, Wolfgang W; Ebeling, Anne

    2016-01-01

    Changes in producer diversity cause multiple changes in consumer communities through various mechanisms. However, past analyses investigating the relationship between plant diversity and arthropod consumers focused only on few aspects of arthropod diversity, e.g. species richness and abundance. Yet, shifts in understudied facets of arthropod diversity like relative abundances or species dominance may have strong effects on arthropod-mediated ecosystem functions. Here we analyze the relationship between plant species richness and arthropod diversity using four complementary diversity indices, namely: abundance, species richness, evenness (equitability of the abundance distribution) and dominance (relative abundance of the dominant species). Along an experimental gradient of plant species richness (1, 2, 4, 8, 16 and 60 plant species), we sampled herbivorous and carnivorous arthropods using pitfall traps and suction sampling during a whole vegetation period. We tested whether plant species richness affects consumer diversity directly (i), or indirectly through increased productivity (ii). Further, we tested the impact of plant community composition on arthropod diversity by testing for the effects of plant functional groups (iii). Abundance and species richness of both herbivores and carnivores increased with increasing plant species richness, but the underlying mechanisms differed between the two trophic groups. While higher species richness in herbivores was caused by an increase in resource diversity, carnivore richness was driven by plant productivity. Evenness of herbivore communities did not change along the gradient in plant species richness, whereas evenness of carnivores declined. The abundance of dominant herbivore species showed no response to changes in plant species richness, but the dominant carnivores were more abundant in species-rich plant communities. The functional composition of plant communities had small impacts on herbivore communities, whereas carnivore communities were affected by forbs of small stature, grasses and legumes. Contrasting patterns in the abundance of dominant species imply different levels of resource specialization for dominant herbivores (narrow food spectrum) and carnivores (broad food spectrum). That in turn could heavily affect ecosystem functions mediated by herbivorous and carnivorous arthropods, such as herbivory or biological pest control. PMID:26859496

  4. Experimental Manipulation of Grassland Plant Diversity Induces Complex Shifts in Aboveground Arthropod Diversity

    PubMed Central

    Hertzog, Lionel R.; Meyer, Sebastian T.; Weisser, Wolfgang W.; Ebeling, Anne

    2016-01-01

    Changes in producer diversity cause multiple changes in consumer communities through various mechanisms. However, past analyses investigating the relationship between plant diversity and arthropod consumers focused only on few aspects of arthropod diversity, e.g. species richness and abundance. Yet, shifts in understudied facets of arthropod diversity like relative abundances or species dominance may have strong effects on arthropod-mediated ecosystem functions. Here we analyze the relationship between plant species richness and arthropod diversity using four complementary diversity indices, namely: abundance, species richness, evenness (equitability of the abundance distribution) and dominance (relative abundance of the dominant species). Along an experimental gradient of plant species richness (1, 2, 4, 8, 16 and 60 plant species), we sampled herbivorous and carnivorous arthropods using pitfall traps and suction sampling during a whole vegetation period. We tested whether plant species richness affects consumer diversity directly (i), or indirectly through increased productivity (ii). Further, we tested the impact of plant community composition on arthropod diversity by testing for the effects of plant functional groups (iii). Abundance and species richness of both herbivores and carnivores increased with increasing plant species richness, but the underlying mechanisms differed between the two trophic groups. While higher species richness in herbivores was caused by an increase in resource diversity, carnivore richness was driven by plant productivity. Evenness of herbivore communities did not change along the gradient in plant species richness, whereas evenness of carnivores declined. The abundance of dominant herbivore species showed no response to changes in plant species richness, but the dominant carnivores were more abundant in species-rich plant communities. The functional composition of plant communities had small impacts on herbivore communities, whereas carnivore communities were affected by forbs of small stature, grasses and legumes. Contrasting patterns in the abundance of dominant species imply different levels of resource specialization for dominant herbivores (narrow food spectrum) and carnivores (broad food spectrum). That in turn could heavily affect ecosystem functions mediated by herbivorous and carnivorous arthropods, such as herbivory or biological pest control. PMID:26859496

  5. T Plant hazards assessment

    SciTech Connect

    Broz, R.E.

    1994-09-27

    This document establishes the technical basis in support of Emergency Planning activities for the T Plant on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE ORDER 5500.3A. Through this document, the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated.

  6. B Plant hazards assessment

    SciTech Connect

    Broz, R.E.

    1994-09-23

    This document establishes the technical basis in support of Emergency Planning Activities for B Plant on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE Order 5500.3A. Through this document, the technical basis for the development of facility specific , Emergency Action Levels and the Emergency Planning Zone is demonstrated.

  7. Assessment of genetic diversity and relationships among caladium cultivars and species using molecular markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Caladium (Caladium hortulanum Birdsey) is an important aroid widely used in the ornamental plant industry. Concerns have been raised about possible loss of genetic diversity due to a drastic decline in the number of cultivars in the last century. This study assessed genetic diversity and relationshi...

  8. Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants.

    PubMed

    Montes-Borrego, Miguel; Lopes, Joao R S; Jiménez-Díaz, Rafael M; Landa, Blanca B

    2015-03-01

    Two haplotypes of Xylella fastidiosa subsp. pauca (Xfp) that correlated with their host of origin were identified in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the gyrB sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of Xfp according to the host source. The protocol proved to be robust for the prediction of the Xfp host source in blind tests using DNA from cultures of the bacterium, infected plants, and insect vectors allowed to feed on Xfp-infected citrus plants. AMOVA and STRUCTURE analyses of microsatellite data separated most Xfp populations on the basis of their host source, indicating that they were genetically distinct. The combined use of the SNaPshot protocol and three previously developed multilocus SSR markers showed that two haplotypes and distinct isolates of Xfp infect citrus and coffee in Brazil and that multiple, genetically different isolates can be present in a single orchard or infect a single tree. This combined approach will be very useful in studies of the epidemiology of Xfp-induced diseases, host specificity of bacterial genotypes, the occurrence of Xfp host jumping, vector feeding habits, etc., in economically important cultivated plants or weed host reservoirs of Xfp in Brazil and elsewhere. PMID:26415663

  9. Environmental filtering explains variation in plant diversity along resource gradients.

    PubMed

    Laliberté, Etienne; Zemunik, Graham; Turner, Benjamin L

    2014-09-26

    The mechanisms that shape plant diversity along resource gradients remain unresolved because competing theories have been evaluated in isolation. By testing multiple theories simultaneously across a >2-million-year dune chronosequence in an Australian biodiversity hotspot, we show that variation in plant diversity is not explained by local resource heterogeneity, resource partitioning, nutrient stoichiometry, or soil fertility along this strong resource gradient. Rather, our results suggest that diversity is determined by environmental filtering from the regional flora, driven by soil acidification during long-term pedogenesis. This finding challenges the prevailing view that resource competition controls local plant diversity along resource gradients, and instead reflects processes shaping species pools over evolutionary time scales. PMID:25258078

  10. Nutritive value in relation to plant species diversity of pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting forage mixtures may benefit pasture herbage production; however, changes in botanical composition could cause unstable nutritive value. Data from two grazing studies and a farm survey were used to examine how plant species diversity influenced herbage nutritive value. In one grazing study,...

  11. Secondary bacterial symbiont community in aphids responds to plant diversity.

    PubMed

    Zytynska, Sharon E; Meyer, Sebastian T; Sturm, Sarah; Ullmann, Wiebke; Mehrparvar, Mohsen; Weisser, Wolfgang W

    2016-03-01

    Biodiversity is important for ecosystem functioning and biotic interactions. In experimental grasslands, increasing plant species richness is known to increase the diversity of associated herbivores and their predators. If these interactions can also involve endosymbionts that reside within a plant or animal host is currently unknown. In plant-feeding aphids, secondary bacterial symbionts can have strong fitness effects on the host, e.g. resistance to natural enemies or fungal pathogens. We examined the secondary symbiont community in three species of aphid, each feeding on a unique host plant across experimental plots that varied in plant species richness. Aphids were collected in May and June, and the symbiont community identified using species-specific PCR assays. Aphis fabae aphids were found to host six different symbiont species with individual aphids co-hosting up to four symbionts. Uroleucon jaceae and Macrosiphum rosae hosted two and three symbiont species, respectively. We found that, at the aphid population level, increasing plant species richness increased the diversity of the aphid symbiont community, whereas at the individual aphid level, the opposite was found. These effects are potentially driven by varying selective pressures across different plant communities of varying diversities, mediated by defensive protection responses and a changing cost-benefit trade-off to the aphid for hosting multiple secondary symbionts. Our work extends documented effects of plant diversity beyond visible biotic interactions to changes in endosymbiont communities, with potentially far-reaching consequences to related ecosystem processes. PMID:26603858

  12. Stability of production and plant species diversity in managed grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant biodiversity theory suggests that increased plant species diversity contributes to the stability of ecosystems. In managed grasslands, such as pastures, greater stability of herbage production would be beneficial. In this retrospective study, I used data from three reports from the 1930s, 1940...

  13. Plant Species Diversity and Pasture Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers face many challenges in pasture management, such as evolving agri-environmental schemes to protect natural resources, and need new management techniques to remain sustainable. Ecological research indicates that increased plant biodiversity benefits ecosystem functions such as primary product...

  14. Plant Diversity Impacts Decomposition and Herbivory via Changes in Aboveground Arthropods

    PubMed Central

    Ebeling, Anne; Meyer, Sebastian T.; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W.

    2014-01-01

    Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

  15. High plant diversity in Eocene South America: Evidence from Patagonia

    USGS Publications Warehouse

    Wilf, P.; Cuneo, N.R.; Johnson, K.R.; Hicks, J.F.; Wing, S.L.; Obradovich, J.D.

    2003-01-01

    Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude ???47??S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was deposited 52 million years ago, the time of the early Eocene climatic optimum, when tropical plant taxa and warm, equable climates reached middle latitudes of both hemispheres. Adjusted for sample size, observed richness exceeds that of any other Eocene leaf flora, supporting an ancient history of high plant diversity in warm areas of South America.

  16. Native plant diversity increases herbivory to non-natives.

    PubMed

    Pearse, Ian S; Hipp, Andrew L

    2014-11-01

    There is often an inverse relationship between the diversity of a plant community and the invasibility of that community by non-native plants. Native herbivores that colonize novel plants may contribute to diversity-invasibility relationships by limiting the relative success of non-native plants. Here, we show that, in large collections of non-native oak trees at sites across the USA, non-native oaks introduced to regions with greater oak species richness accumulated greater leaf damage than in regions with low oak richness. Underlying this trend was the ability of herbivores to exploit non-native plants that were close relatives to their native host. In diverse oak communities, non-native trees were on average more closely related to native trees and received greater leaf damage than those in depauperate oak communities. Because insect herbivores colonize non-native plants that are similar to their native hosts, in communities with greater native plant diversity, non-natives experience greater herbivory. PMID:25232143

  17. Phytochrome diversity in green plants and the origin of canonical plant phytochromes.

    PubMed

    Li, Fay-Wei; Melkonian, Michael; Rothfels, Carl J; Villarreal, Juan Carlos; Stevenson, Dennis W; Graham, Sean W; Wong, Gane Ka-Shu; Pryer, Kathleen M; Mathews, Sarah

    2015-01-01

    Phytochromes are red/far-red photoreceptors that play essential roles in diverse plant morphogenetic and physiological responses to light. Despite their functional significance, phytochrome diversity and evolution across photosynthetic eukaryotes remain poorly understood. Using newly available transcriptomic and genomic data we show that canonical plant phytochromes originated in a common ancestor of streptophytes (charophyte algae and land plants). Phytochromes in charophyte algae are structurally diverse, including canonical and non-canonical forms, whereas in land plants, phytochrome structure is highly conserved. Liverworts, hornworts and Selaginella apparently possess a single phytochrome, whereas independent gene duplications occurred within mosses, lycopods, ferns and seed plants, leading to diverse phytochrome families in these clades. Surprisingly, the phytochrome portions of algal and land plant neochromes, a chimera of phytochrome and phototropin, appear to share a common origin. Our results reveal novel phytochrome clades and establish the basis for understanding phytochrome functional evolution in land plants and their algal relatives. PMID:26215968

  18. Phytochrome diversity in green plants and the origin of canonical plant phytochromes

    PubMed Central

    Li, Fay-Wei; Melkonian, Michael; Rothfels, Carl J.; Villarreal, Juan Carlos; Stevenson, Dennis W.; Graham, Sean W.; Wong, Gane Ka-Shu; Pryer, Kathleen M.; Mathews, Sarah

    2015-01-01

    Phytochromes are red/far-red photoreceptors that play essential roles in diverse plant morphogenetic and physiological responses to light. Despite their functional significance, phytochrome diversity and evolution across photosynthetic eukaryotes remain poorly understood. Using newly available transcriptomic and genomic data we show that canonical plant phytochromes originated in a common ancestor of streptophytes (charophyte algae and land plants). Phytochromes in charophyte algae are structurally diverse, including canonical and non-canonical forms, whereas in land plants, phytochrome structure is highly conserved. Liverworts, hornworts and Selaginella apparently possess a single phytochrome, whereas independent gene duplications occurred within mosses, lycopods, ferns and seed plants, leading to diverse phytochrome families in these clades. Surprisingly, the phytochrome portions of algal and land plant neochromes, a chimera of phytochrome and phototropin, appear to share a common origin. Our results reveal novel phytochrome clades and establish the basis for understanding phytochrome functional evolution in land plants and their algal relatives. PMID:26215968

  19. Assessing fungal root colonization for plant improvement

    PubMed Central

    Jansson, Hans-Börje; Lopez-Llorca, Luis V

    2009-01-01

    Fungal endophytes display a broad range of symbiotic interactions with their host plants. Current studies on their biology, diversity and benefits are unravelling their high relevance on plant adaptation to environmental stresses. Implementation of such properties may open new perspectives in agriculture and forestry. We aim to exploit the endophytic capacities of the fungal species Fusarium equiseti, a naturally occurring root endophyte which has shown antagonism to plant pathogens, and Pochonia chlamydosporia, a nematophagous fungus with putative endophytic behavior, for plant protection and adaptation to biotic and abiotic stress. A real-time PCR protocol for quantification of the fungal population, together with Agrobacterium-mediated genetic transformation with the GFP gene for confocal microscopy analyses, were designed and applied to assess endophytic development of both these fungal species. Although quantification of both F. equiseti and P. chlamydosporia yielded similar degrees of root colonization, microscopical observations demonstrated differences in infection and development patterns. Furthermore, we found evidences of plant response against endophyte colonization, supporting a balanced antagonism between the endophyte virulence and the plant defenses. Optimization and application of the methodologies presented herein will allow elucidation of beneficial interactions among these endophytes and their host plants. PMID:19816102

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

    PubMed Central

    Janz, Niklas; Nylin, Sören; Wahlberg, Niklas

    2006-01-01

    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. PMID:16420707

  1. Putting the Plants Back into Plant Ecology: Six Pragmatic Models for Understanding and Conserving Plant Diversity

    PubMed Central

    KEDDY, PAUL

    2005-01-01

    • Background There is a compelling need to protect natural plant communities and restore them in degraded landscapes. Activities must be guided by sound scientific principles, practical conservation tools, and clear priorities. With perhaps one-third of the world's flora facing extinction, scientists and conservation managers will need to work rapidly and collaboratively, recognizing each other's strengths and limitations. As a guide to assist managers in maintaining plant diversity, six pragmatic models are introduced that are already available. Although theoretical models continue to receive far more space and headlines in scientific journals, more managers need to understand that pragmatic, rather than theoretical, models have the most promise for yielding results that can be applied immediately to plant communities. • Six Pragmatic Models For each model, key citations and an array of examples are provided, with particular emphasis on wetlands, since ‘wet and wild’ was my assigned theme for the Botanical Society of America in 2003. My own work may seem rather prominent, but the application and refinement of these models has been a theme for me and my many students over decades. The following models are reviewed: (1) species–area: larger areas usually contain more species; (2) species–biomass: plant diversity is maximized at intermediate levels of biomass; (3) centrifugal organization: multiple intersecting environmental gradients maintain regional landscape biodiversity; (4) species–frequency: a few species are frequent while most are infrequent; (5) competitive hierarchies: in the absence of constraints, large canopy-forming species dominate patches of landscape, reducing biological diversity; and (6) intermediate disturbance: perturbations such as water level fluctuations, fire and grazing are essential for maintaining plant diversity. • Conclusions The good news is that managers faced with protecting or restoring landscapes already have this arsenal of tools at their disposal. The bad news is that far too few of these models are appreciated. PMID:15944176

  2. Influence of plant diversity and elevated atmospheric carbon dioxide levels on belowground bacterial diversity

    PubMed Central

    Grüter, Dominique; Schmid, Bernhard; Brandl, Helmut

    2006-01-01

    Background Changes in aboveground plant species diversity as well as variations of environmental conditions such as exposure of ecosystems to elevated concentrations of atmospheric carbon dioxide may lead to changes in metabolic activity, composition and diversity of belowground microbial communities, both bacterial and fungal. Results We examined soil samples taken from a biodiversity × CO2 grassland experiment where replicate plots harboring 5, 12, or 31 different plant species had been exposed to ambient or elevated (600 ppm) levels of carbon dioxide for 5 years. Analysis of soil bacterial communities in these plots by temporal temperature gradient gel electrophoresis (TTGE) showed that dominant soil bacterial populations varied only very little between different experimental treatments. These populations seem to be ubiquitous. Likewise, screening of samples on a high-resolution level by terminal restriction fragment length polymorphism (T-RFLP) showed that increased levels of carbon dioxide had no significant influence on both soil bacterial community composition (appearance and frequency of operational taxonomic units, OTUs) and on bacterial richness (total number of different OTUs). In contrast, differences in plant diversity levels had a significant effect on bacterial composition but no influence on bacterial richness. Regarding species level, several bacterial species were found only in specific plots and were related to elevated carbon dioxide or varying plant diversity levels. For example, analysis of T-RFLP showed that the occurrence of Salmonella typhimurium was significantly increased in plots exposed to elevated CO2 (P < 0.05). Conclusion Plant diversity levels are affecting bacterial composition (bacterial types and their frequency of occurrence). Elevated carbon dioxide does not lead to quantitative alteration (bacterial richness), whereas plant diversity is responsible for qualitative changes (bacterial diversity). PMID:16872510

  3. Increasing land-use intensity decreases floral colour diversity of plant communities in temperate grasslands.

    PubMed

    Binkenstein, Julia; Renoult, Julien P; Schaefer, H Martin

    2013-10-01

    To preserve biodiversity and ecosystem functions in a globally changing world it is crucial to understand the effect of land use on ecosystem processes such as pollination. Floral colouration is known to be central in plant-pollinator interactions. To date, it is still unknown whether land use affects the colouration of flowering plant communities. To assess the effect of land use on the diversity and composition of flower colours in temperate grasslands, we collected data on the number of flowering plant species, blossom cover and flower reflectance spectra from 69 plant communities in two German regions, Schwäbische Alb (SA) and Hainich-Dün (HD). We analysed reflectance data of flower colours as they are perceived by honeybees and studied floral colour diversity based upon spectral loci of each flowering plant species in the Maxwell triangle. Before the first mowing, flower colour diversity decreased with increasing land-use intensity in SA, accompanied by a shift of mean flower colours of communities towards an increasing proportion of white blossom cover in both regions. By changing colour characteristics of grasslands, we suggest that increasing land-use intensity can affect the flower visitor fauna in terms of visitor behaviour and diversity. These changes may in turn influence plant reproduction in grassland plant communities. Our results indicate that land use is likely to affect communication processes between plants and flower visitors by altering flower colour traits. PMID:23568710

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

    NASA Astrophysics Data System (ADS)

    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 quality vegetation survey datasets, including Duke Forest Korstian permanent plots, Forest Inventory Analysis (FIA), and the scale transgressive, nested module Carolina Vegetation Survey (CVS).

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

    USGS Publications Warehouse

    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.

  6. Analysis of plant diversity with retrotransposon-based molecular markers

    PubMed Central

    Kalendar, R; Flavell, A J; Ellis, T H N; Sjakste, T; Moisy, C; Schulman, A H

    2011-01-01

    Retrotransposons are both major generators of genetic diversity and tools for detecting the genomic changes associated with their activity because they create large and stable insertions in the genome. After the demonstration that retrotransposons are ubiquitous, active and abundant in plant genomes, various marker systems were developed to exploit polymorphisms in retrotransposon insertion patterns. These have found applications ranging from the mapping of genes responsible for particular traits and the management of backcrossing programs to analysis of population structure and diversity of wild species. This review provides an insight into the spectrum of retrotransposon-based marker systems developed for plant species and evaluates the contributions of retrotransposon markers to the analysis of population diversity in plants. PMID:20683483

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

    PubMed

    Borer, Elizabeth T; Seabloom, Eric W; Gruner, Daniel S; Harpole, W Stanley; Hillebrand, Helmut; Lind, Eric M; Adler, 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, Chengjin; Cleland, Elsa E; Crawley, Michael J; Daleo, Pedro; Damschen, Ellen I; 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

    2014-04-24

    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. PMID:24670649

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

    SciTech Connect

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

    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 the same technology, and (3) different architectures within the same technology. Using this convention, the first diversity usage family, designated Strategy A, is characterized by fundamentally diverse technologies. Strategy A at the system or platform level is illustrated by the example of analog and digital implementations. The second diversity usage family, designated Strategy B, is achieved through the use of distinctly different technologies. Strategy B can be described in terms of different digital technologies, such as the distinct approaches represented by general-purpose microprocessors and field-programmable gate arrays. The third diversity usage family, designated Strategy C, involves the use of variations within a technology. An example of Strategy C involves different digital architectures within the same technology, such as that provided by different microprocessors (e.g., Pentium and Power PC). The grouping of diversity criteria combinations according to Strategies A, B, and C establishes baseline diversity usage and facilitates a systematic organization of strategic approaches for coping with CCF vulnerabilities. Effectively, these baseline sets of diversity criteria constitute appropriate CCF mitigating strategies for digital safety systems. The strategies represent guidance on acceptable diversity usage and can be applied directly to ensure that CCF vulnerabilities identified through a D3 assessment have been adequately resolved. Additionally, a framework has been generated for capturing practices regarding diversity usage and a tool has been developed for the systematic assessment of the comparative effect of proposed diversity strategies (see Appendix A).

  9. Does plant species co-occurrence influence soil mite diversity?

    PubMed

    St John, Mark G; Wall, Diana H; Behan-Pelletier, Valerie M

    2006-03-01

    Few studies have considered whether plant taxa can be used as predictors of belowground faunal diversity in natural ecosystems. We examined soil mite (Acari) diversity beneath six grass species at the Konza Prairie Biological Station, Kansas, USA. We tested the hypotheses that soil mite species richness, abundance, and taxonomic diversity are greater (1) beneath grasses in dicultures (different species) compared to monocultures (same species), (2) beneath grasses of higher resource quality (lower C:N) compared to lower resource quality, and (3) beneath heterogeneous mixes of grasses (C3 and C4 grasses growing together) compared to homogeneous mixes (C3 or C4 grasses) using natural occurrences of plant species as treatments. This study is the first to examine the interaction between above- and belowground diversity in a natural setting with species-level resolution of a hyper-diverse taxon. Our results indicate that grasses in diculture supported a more species and phylogenetically rich soil mite fauna than was observed for monocultures and that this relationship was significant at depth but not in the upper soil horizon. We noted that mite species richness was not linearly related to grass species richness, which suggests that simple extrapolations of soil faunal diversity based on plant species inventories may underestimate the richness of associated soil mite communities. The distribution of mite size classes in dicultures was considerably different than those for monocultures. There was no difference in soil mite richness between grass combinations of differing resource quality, or resource heterogeneity. PMID:16602292

  10. Gene transfer to plants by diverse species of bacteria.

    PubMed

    Broothaerts, Wim; Mitchell, Heidi J; Weir, Brian; Kaines, Sarah; Smith, Leon M A; Yang, Wei; Mayer, Jorge E; Roa-Rodríguez, Carolina; Jefferson, Richard A

    2005-02-10

    Agrobacterium is widely considered to be the only bacterial genus capable of transferring genes to plants. When suitably modified, Agrobacterium has become the most effective vector for gene transfer in plant biotechnology. However, the complexity of the patent landscape has created both real and perceived obstacles to the effective use of this technology for agricultural improvements by many public and private organizations worldwide. Here we show that several species of bacteria outside the Agrobacterium genus can be modified to mediate gene transfer to a number of diverse plants. These plant-associated symbiotic bacteria were made competent for gene transfer by acquisition of both a disarmed Ti plasmid and a suitable binary vector. This alternative to Agrobacterium-mediated technology for crop improvement, in addition to affording a versatile 'open source' platform for plant biotechnology, may lead to new uses of natural bacteria-plant interactions to achieve plant transformation. PMID:15703747

  11. Assessment of molecular diversity and population structure of the Ethiopian sorghum [Sorghum bicolor L. (Moench)] germplasm collection maintained by the USDA-ARS National Plant Germplasm System using SSR markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genetic diversity and population structure present in the Ethiopian sorghum collection maintained at the USDA-ARS National Plant Germplasm System (NPGS) has not been studied. In addition, 83% of the accessions in the Ethiopian collection lack passport information which has constrained their eval...

  12. Plant diversity affects behavior of generalist root herbivores, reduces crop damage, and enhances crop yield.

    PubMed

    Staudacher, Karin; Schallhart, Nikolaus; Thalinger, Bettina; Wallinger, Corinna; Juen, Anita; Traugott, Michael

    2013-07-01

    Soil-dwelling pests inflict considerable economic damage in agriculture but are hard to control. A promising strategy to reduce pest pressure on crops is to increase the plant diversity in agroecosystems. This approach, however, demands a sound understanding of species' interactions, which is widely lacking for subterranean herbivore-plant systems. Here, we examine the effects of plant diversification on wireworms, the soil-dwelling larvae of click beetles that threaten crops worldwide. We conducted a field experiment employing plant diversification by adding either wheat or a mix of six associated plants (grasses, legumes, and forbs) between rows of maize to protect it from Agriotes wireworms. Wireworm feeding behavior, dispersal between crop and associated plants, as well as maize damage and yield were examined. The former was assessed combining molecular gut content and stable isotope analysis. The pests were strongly attracted by the associated plants in August, when the crop was most vulnerable, whereas in September, shortly before harvest, this effect occurred only in the plant mix. In maize monoculture, the larvae stayed in the principal crop throughout the season. Larval delta13C signatures revealed that maize feeding was reduced up to sevenfold in wireworms of the vegetationally diversified treatments compared to those of the maize monoculture. These findings were confirmed by molecular analysis, which additionally showed a dietary preference of wireworms for specific plants in the associated plant mix. Compared to the monoculture, maize damage was reduced by 38% and 55% in the wheat and plant mix treatment, which translated into a yield increase of 30% and 38%, respectively. The present findings demonstrate that increasing the plant diversity in agroecosystems provides an effective insurance against soil pests. The underlying mechanisms are the diversion of the pest from the principle crop and a changed feeding behavior. The deployment of diverse mixes of associated plants, tailored to the specific preferences of the soil herbivores, provides a promising strategy for managing subterranean pests while maintaining crop yield. PMID:23967581

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

    PubMed Central

    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. PMID:26781165

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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-m(2) 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. PMID:26781165

  16. Assessing Dispositions toward Cultural Diversity among Preservice Teachers.

    ERIC Educational Resources Information Center

    Dee, Jay R.; Henkin, Alan B.

    2002-01-01

    Assessed preservice teachers' attitudes toward cultural diversity prior to entering into multicultural education courses at an urban university. Respondents indicated strong support for implementing diversity issues in the classroom and high levels of agreement with equity beliefs and the social value of diversity. They did not agree that…

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

    PubMed Central

    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

  18. Nematicide impacts on nematodes and feedbacks on plant productivity in a plant diversity gradient

    NASA Astrophysics Data System (ADS)

    Eisenhauer, Nico; Ackermann, Michael; Gass, Svenja; Klier, Matthias; Migunova, Varvara; Nitschke, Norma; Ruess, Liliane; Sabais, Alexander C. W.; Weisser, Wolfgang W.; Scheu, Stefan

    2010-09-01

    A major issue in current ecological research is the effect of biodiversity on ecosystem functioning. Although several studies reported a positive diversity - productivity relationship, the role of soil animals has been largely neglected. Nematodes are among the most widespread and important herbivores causing substantial yield losses in agriculture; however, impacts of nematodes on the diversity - productivity relationship in semi-natural plant communities have not been investigated until today. In the framework of the Jena Experiment (Thuringia, Germany) we established control and nematicide treated subplots to manipulate nematode densities on plots varying in plant species (1-16) and functional group richness (1-4). We explored the interacting effects of nematicide application and plant diversity on the main trophic groups of nematodes and on aboveground plant productivity. Nematicide application reduced the number of nematodes significantly, particularly that of plant feeders and predators. The negative impact of nematicide application on plant and bacterial feeders depended however on the diversity of the plant community. Total plant shoot biomass tended to decrease in the presence of ambient nematode densities. In detail, nematode effects varied however with plant functional group identity by reducing only the shoot biomass of herbs significantly but not that of legumes. Furthermore, the shoot biomass of grasses tended to decrease in the presence of ambient nematode densities. In contrast to total shoot biomass, nematodes decreased grass shoot biomass only in high diverse but not in low diverse plant communities. Thus, the present study for the first time highlights that nematodes likely modify the community structure und functions of semi-natural plant communities by altering the competition between plant functional groups and by attenuating the diversity - productivity relationship.

  19. Explicit Diversity Index (EDI): a novel measure for assessing the diversity of compound databases.

    PubMed

    Papp, Akos; Gulyas-Forró, Anna; Gulyas, Zsolt; Dorman, György; Urge, Laszló; Darvas, Ferenc

    2006-01-01

    A novel diversity assessment method, the Explicit Diversity Index (EDI), is introduced for druglike molecules. EDI combines structural and synthesis-related dissimilarity values and expresses them as a single number. As an easily interpretable measure, it facilitates the decision making in the design of combinatorial libraries, and it might assist in the comparison of compound sets provided by different manufacturers. Because of its rapid calculation algorithm, EDI enables the diversity assessment of in-house or commercial compound collections. PMID:16995719

  20. Plant Sterol Diversity in Pollen from Angiosperms.

    PubMed

    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. PMID:25820807

  1. PLANT SPECIES DIVERSITY, ECOSYSTEM FUNCTION, AND PASTURE MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grassland farmers face new challenges in pasture management including improving sustainability, reducing inputs of fertilizers and pesticides, and protecting soil resources. Managing plant diversity within and among pastures may be one tool to aid producers in meeting these new challenges. Pasture e...

  2. Running up the scale: From plant traits to beta diversity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landscape ecologists often consider a hierarchy of scales, from individual species to communities to landscapes. Beta diversity can anchor a conceptual framework linking major concepts in ecology, building from plant physiological and structural traits that determine the fundamental niche, through c...

  3. THE EFFECTIVENESS OF QUADRATS FOR MEASURING VASCULAR PLANT DIVERSITY

    EPA Science Inventory

    Quadrats are widely used for measuring characteristics of vascular plant communities. It is well recognized that quadrat size affects measurements of frequency and cover. The ability of quadrats of varying sizes to adequately measure diversity has not been established. An exha...

  4. Diversity in Plant Breeding: A New Conceptual Framework.

    PubMed

    Litrico, Isabelle; Violle, Cyrille

    2015-10-01

    Faced with an accelerating rate of environmental change and the associated need for a more sustainable, low-input agriculture, the urgent new challenge for crop science is to find ways to introduce greater diversity to cropping systems. However, there is a dearth of generic formalism in programs seeking to diversify crops. In this opinion, we propose a new framework, derived from ecological theory, that should enable diversity targets to be incorporated into plant-breeding programs. While ecological theory provides criteria for maintaining diversity and optimizing the production of mixtures, such criteria are rarely fully realized in natural ecosystems. Conversely, crop breeding should optimize both agronomic value and the ability of plants to perform and live alongside one another. This framework represents an opportunity to develop more sustainable crops and also a radical new way to apply ecological theory to cropping systems. PMID:26440430

  5. Plant-plant interactions, environmental gradients and plant diversity: a global synthesis of community-level studies

    PubMed Central

    Soliveres, Santiago; Maestre, Fernando T.

    2015-01-01

    Previous syntheses on the effects of environmental conditions on the outcome of plant-plant interactions summarize results from pairwise studies. However, the upscaling to the community-level of such studies is problematic because of the existence of multiple species assemblages and species-specific responses to both the environmental conditions and the presence of neighbors. We conducted the first global synthesis of community-level studies from harsh environments, which included data from 71 alpine and 137 dryland communities. Here we: i) test how important are facilitative interactions as a driver of community structure, ii) evaluate whether the frequency of positive plant-plant interactions across differing environmental conditions and habitats is predictable, and iii) assess whether thresholds in the response of plant-plant interactions to environmental gradients exists between “moderate” and “extreme” stress levels. We also used those community-level studies performed across gradients of at least three points to evaluate how the average environmental conditions, the length of the gradient studied, and the number of points sampled across such gradient affect the form and strength of the facilitation-environment relationship. Over 25% of the species present were more spatially associated to nurse plants than expected by chance in both alpine and dryland areas, illustrating the high importance of positive plant-plant interactions for the maintenance of plant diversity. Facilitative interactions were more frequent, and more related to environmental conditions, in alpine than in dryland areas, perhaps because drylands are generally characterized by a larger variety of environmental stress factors and plant functional traits. The frequency of facilitative interactions in alpine communities peaked at 1000 mm of annual rainfall, and globally decreased with elevation. The frequency of positive interactions in dryland communities decreased globally with water scarcity or temperature annual range. Positive facilitation-drought stress relationships are more likely in shorter regional gradients, but these relationships are obscured in regions with a greater species turnover or with complex environmental gradients. By showing the different climatic drivers and behaviors of plant-plant interactions in dryland and alpine areas, our results will improve predictions regarding the effect of facilitation on the assembly of plant communities and their response to changes in environmental conditions. PMID:25914603

  6. Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots.

    PubMed

    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. PMID:17646952

  7. Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots

    NASA Astrophysics Data System (ADS)

    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.

  8. Competition–defense tradeoffs and the maintenance of plant diversity

    PubMed Central

    Viola, David V.; Mordecai, Erin A.; Jaramillo, Alejandra G.; Sistla, Seeta A.; Albertson, Lindsey K.; Gosnell, J. Stephen; Cardinale, Bradley J.; Levine, Jonathan M.

    2010-01-01

    Ecologists have long observed that consumers can maintain species diversity in communities of their prey. Many theories of how consumers mediate diversity invoke a tradeoff between species’ competitive ability and their ability to withstand predation. Under this constraint, the best competitors are also most susceptible to consumers, preventing them from excluding other species. However, empirical evidence for competition–defense tradeoffs is limited and, as such, the mechanisms by which consumers regulate diversity remain uncertain. We performed a meta-analysis of 36 studies to evaluate the prevalence of the competition–defense tradeoff and its role in maintaining diversity in plant communities. We quantified species’ responses to experimental resource addition and consumer removal as estimates of competitive ability and resistance to consumers, respectively. With this analysis, we found mixed empirical evidence for a competition–defense tradeoff; in fact, competitive ability tended to be weakly positively correlated with defense overall. However, when present, negative relationships between competitive ability and defense influenced species diversity in the manner predicted by theory. In the minority of communities for which a tradeoff was detected, species evenness was higher, and resource addition and consumer removal reduced diversity. Our analysis reframes the commonly held notion that consumers structure plant communities through a competition–defense tradeoff. Such a tradeoff can maintain diversity when present, but negative correlations between competitive ability and defense were less common than is often assumed. In this respect, this study supports an emerging theoretical paradigm in which predation interacts with competition to both enhance and reduce species diversity. PMID:20855605

  9. Arctic plant diversity in the Early Eocene greenhouse

    PubMed Central

    Harrington, Guy J.; Eberle, Jaelyn; Le-Page, Ben A.; Dawson, Mary; Hutchison, J. Howard

    2012-01-01

    For the majority of the Early Caenozoic, a remarkable expanse of humid, mesothermal to temperate forests spread across Northern Polar regions that now contain specialized plant and animal communities adapted to life in extreme environments. Little is known on the taxonomic diversity of Arctic floras during greenhouse periods of the Caenozoic. We show for the first time that plant richness in the globally warm Early Eocene (approx. 55–52 Myr) in the Canadian High Arctic (76° N) is comparable with that approximately 3500 km further south at mid-latitudes in the US western interior (44–47° N). Arctic Eocene pollen floras are most comparable in richness with today's forests in the southeastern United States, some 5000 km further south of the Arctic. Nearly half of the Eocene, Arctic plant taxa are endemic and the richness of pollen floras implies significant patchiness to the vegetation type and clear regional richness of angiosperms. The reduced latitudinal diversity gradient in Early Eocene North American plant species demonstrates that extreme photoperiod in the Arctic did not limit taxonomic diversity of plants. PMID:22072610

  10. Fungal Diversity Associated with Hawaiian Drosophila Host Plants

    PubMed Central

    Ort, Brian S.; Bantay, Roxanne M.; Pantoja, Norma A.; O’Grady, Patrick M.

    2012-01-01

    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. PMID:22911703

  11. Using Plant Functional Traits to Explain Diversity–Productivity Relationships

    PubMed Central

    Roscher, Christiane; Schumacher, Jens; Gubsch, Marlén; Lipowsky, Annett; Weigelt, Alexandra; Buchmann, Nina; Schmid, Bernhard; Schulze, Ernst-Detlef

    2012-01-01

    Background The different hypotheses proposed to explain positive species richness–productivity relationships, i.e. selection effect and complementarity effect, imply that plant functional characteristics are at the core of a mechanistic understanding of biodiversity effects. Methodology/Principal Findings We used two community-wide measures of plant functional composition, (1) community-weighted means of trait values (CWM) and (2) functional trait diversity based on Rao’s quadratic diversity (FDQ) to predict biomass production and measures of biodiversity effects in experimental grasslands (Jena Experiment) with different species richness (2, 4, 8, 16 and 60) and different functional group number and composition (1 to 4; legumes, grasses, small herbs, tall herbs) four years after establishment. Functional trait composition had a larger predictive power for community biomass and measures of biodiversitity effects (40–82% of explained variation) than species richness per se (<1–13% of explained variation). CWM explained a larger amount of variation in community biomass (80%) and net biodiversity effects (70%) than FDQ (36 and 38% of explained variation respectively). FDQ explained similar proportions of variation in complementarity effects (24%, positive relationship) and selection effects (28%, negative relationship) as CWM (27% of explained variation for both complementarity and selection effects), but for all response variables the combination of CWM and FDQ led to significant model improvement compared to a separate consideration of different components of functional trait composition. Effects of FDQ were mainly attributable to diversity in nutrient acquisition and life-history strategies. The large spectrum of traits contributing to positive effects of CWM on biomass production and net biodiversity effects indicated that effects of dominant species were associated with different trait combinations. Conclusions/Significance Our results suggest that the identification of relevant traits and the relative impacts of functional identity of dominant species and functional diversity are essential for a mechanistic understanding of the role of plant diversity for ecosystem processes such as aboveground biomass production. PMID:22623961

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

    PubMed

    Köberl, Martina; Schmidt, Ruth; Ramadan, Elshahat M; Bauer, Rudolf; Berg, Gabriele

    2013-01-01

    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. PMID:24391634

  13. Global patterns and determinants of vascular plant diversity.

    PubMed

    Kreft, Holger; Jetz, Walter

    2007-04-01

    Plants, with an estimated 300,000 species, provide crucial primary production and ecosystem structure. To date, our quantitative understanding of diversity gradients of megadiverse clades such as plants has been hampered by the paucity of distribution data. Here, we investigate the global-scale species-richness pattern of vascular plants and examine its environmental and potential historical determinants. Across 1,032 geographic regions worldwide, potential evapotranspiration, the number of wet days per year, and measurements of topographical and habitat heterogeneity emerge as core predictors of species richness. After accounting for environmental effects, the residual differences across the major floristic kingdoms are minor, with the exception of the uniquely diverse Cape Region, highlighting the important role of historical contingencies. Notably, the South African Cape region contains more than twice as many species as expected by the global environmental model, confirming its uniquely evolved flora. A combined multipredictor model explains approximately 70% of the global variation in species richness and fully accounts for the enigmatic latitudinal gradient in species richness. The models illustrate the geographic interplay of different environmental predictors of species richness. Our findings highlight that different hypotheses about the causes of diversity gradients are not mutually exclusive, but likely act synergistically with water-energy dynamics playing a dominant role. The presented geostatistical approach is likely to prove instrumental for identifying richness patterns of the many other taxa without single-species distribution data that still escape our understanding. PMID:17379667

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

    SciTech Connect

    Borer, Elizabeth T.; 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.

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

    PubMed

    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 < 0.05). Soil fungal richness was positively associated with plant richness, biomass, CWM plant height, and soil gradient aggregated from the principal component analysis, but SEM results showed that plant richness and CWM plant height determined by soil properties were the main factors exerting direct effects. Soil gradient increased fungal richness through indirect effect on vegetation rather than direct effect. The negative indirect effect of FDis on soil fungal richness was through its effect on plant biomass. Our final SEM model based on plant 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. PMID:26811795

  16. Institutional Responses to Quality Assessment: Developing Diversity.

    ERIC Educational Resources Information Center

    Massaro, Vin

    1996-01-01

    This paper argues that in the last decade, Australian higher education has moved from a relatively regulated to a largely unregulated model, resulting in reduction of institutional diversity. The advent of external quality assurance processes that reward the traditional notion of universities has further homogenized the system and diluted…

  17. Charting a Course for Diversity: An Experience in Climate Assessment

    ERIC Educational Resources Information Center

    Royse, Molly; Conner, Tiffani; Miller, Tamara

    2006-01-01

    The University of Tennessee Libraries' Diversity Committee administered a climate assessment survey to determine the readiness of the libraries for a comprehensive diversity initiative. This article discusses the design and methodology of the survey and analyzes the results. The survey served as a valuable starting point in charting a successful…

  18. Macroevolution and the biological diversity of plants and herbivores

    PubMed Central

    Futuyma, Douglas J.; Agrawal, Anurag A.

    2009-01-01

    Terrestrial biodiversity is dominated by plants and the herbivores that consume them, and they are one of the major conduits of energy flow up to higher trophic levels. Here, we address the processes that have generated the spectacular diversity of flowering plants (>300,000 species) and insect herbivores (likely >1 million species). Long-standing macroevolutionary hypotheses have postulated that reciprocal evolution of adaptations and subsequent bursts of speciation have given rise to much of this biodiversity. We critically evaluate various predictions based on this coevolutionary theory. Phylogenetic reconstruction of ancestral states has revealed evidence for escalation in the potency or variety of plant lineages' chemical defenses; however, escalation of defense has been moderated by tradeoffs and alternative strategies (e.g., tolerance or defense by biotic agents). There is still surprisingly scant evidence that novel defense traits reduce herbivory and that such evolutionary novelty spurs diversification. Consistent with the coevolutionary hypothesis, there is some evidence that diversification of herbivores has lagged behind, but has nevertheless been temporally correlated with that of their host-plant clades, indicating colonization and radiation of insects on diversifying plants. However, there is still limited support for the role of host-plant shifts in insect diversification. Finally, a frontier area of research, and a general conclusion of our review, is that community ecology and the long-term evolutionary history of plant and insect diversification are inexorably intertwined. PMID:19815508

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

    PubMed Central

    Köberl, Martina; Schmidt, Ruth; Ramadan, Elshahat M.; Bauer, Rudolf; Berg, Gabriele

    2013-01-01

    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. PMID:24391634

  20. Small RNA Diversity in Plants and its Impact in Development

    PubMed Central

    Lelandais-Brière, Christine; Sorin, Céline; Declerck, Marie; Benslimane, Abdelali; Crespi, Martin; Hartmann, Caroline

    2010-01-01

    MicroRNAs are a class of non-coding RNAs involved in post-transcriptional control of gene expression, either via degradation or translational inhibition of target mRNAs. Both experimental and computational approaches have been used to identify miRNAs and their target genes. In plants, deep sequencing methods have recently allowed the analysis of small RNA diversity in different species and/or mutants. Most sequencing efforts have been concentrated on the identification of miRNAs and their mRNA targets have been predicted based on complementarity criteria. The recent demonstration that certain plant miRNAs could act partly via inhibition of protein translation certainly opens new fields of analysis for plant miRNA function on a broader group of targets. The roles of conserved miRNAs on target mRNA stability have been analysed in different species and defined common mechanisms in development and stress responses. In contrast, much less is known about expression patterns or functions of non-conserved miRNAs. In this review, we focus on the comparative analyses of plant small RNA diversity and the action of si/miRNAs in post-transcriptional regulation of some key genes involved in root development. PMID:20808519

  1. Effects of riparian plant diversity loss on aquatic microbial decomposers become more pronounced with increasing time.

    PubMed

    Fernandes, Isabel; Duarte, Sofia; Cássio, Fernanda; Pascoal, Cláudia

    2013-11-01

    We examined the potential long-term impacts of riparian plant diversity loss on diversity and activity of aquatic microbial decomposers. Microbial assemblages were obtained in a mixed-forest stream by immersion of mesh bags containing three leaf species (alder, oak and eucalyptus), commonly found in riparian corridors of Iberian streams. Simulation of species loss was done in microcosms by including a set of all leaf species, retrieved from the stream, and non-colonized leaves of three, two or one leaf species. Leaves were renewed every month throughout six months, and microbial inoculum was ensured by a set of colonized leaves from the previous month. Microbial diversity, leaf mass loss and fungal biomass were assessed at the second and sixth months after plant species loss. Molecular diversity of fungi and bacteria, as the total number of operational taxonomic units per leaf diversity treatment, decreased with leaf diversity loss. Fungal biomass tended to decrease linearly with leaf species loss on oak and eucalyptus, suggesting more pronounced effects of leaf diversity on lower quality leaves. Decomposition of alder and eucalyptus leaves was affected by leaf species identity, mainly after longer times following diversity loss. Leaf decomposition of alder decreased when mixed with eucalyptus, while decomposition of eucalyptus decreased in mixtures with oak. Results suggest that the effects of leaf diversity on microbial decomposers depended on leaf species number and also on which species were lost from the system, especially after longer times. This may have implications for the management of riparian forests to maintain stream ecosystem functioning. PMID:23963224

  2. Endophytic Fungal Communities Associated with Vascular Plants in the High Arctic Zone Are Highly Diverse and Host-Plant Specific

    PubMed Central

    Zhang, Tao; Yao, Yi-Feng

    2015-01-01

    This study assessed the diversity and distribution of endophytic fungal communities associated with the leaves and stems of four vascular plant species in the High Arctic using 454 pyrosequencing with fungal-specific primers targeting the ITS region. Endophytic fungal communities showed high diversity. The 76,691 sequences obtained belonged to 250 operational taxonomic units (OTUs). Of these OTUs, 190 belonged to Ascomycota, 50 to Basidiomycota, 1 to Chytridiomycota, and 9 to unknown fungi. The dominant orders were Helotiales, Pleosporales, Capnodiales, and Tremellales, whereas the common known fungal genera were Cryptococcus, Rhizosphaera, Mycopappus, Melampsora, Tetracladium, Phaeosphaeria, Mrakia, Venturia, and Leptosphaeria. Both the climate and host-related factors might shape the fungal communities associated with the four Arctic plant species in this region. These results suggested the presence of an interesting endophytic fungal community and could improve our understanding of fungal evolution and ecology in the Arctic terrestrial ecosystems. PMID:26067836

  3. DUE Diversity 2010- Biodiversity 2010 Target Assessment

    NASA Astrophysics Data System (ADS)

    Kleeschulte, Stefan; Gangkofner, Ute; Paganini, Marc

    2010-12-01

    The objectives of the DIVERSITY2010 project were defined with regard to the biodiversity 2010 target of monitoring biodiversity loss. The aim was to identify trends in different ecosystems based on existing global land cover databases. The implementation of the project faced two main problems: the fact that land cover can only be used as a proxy for ecosystems and habitats and secondly that the different global land cover databases have a limited comparability and thus differences between two databases cannot directly be attributed to trends in ecosystems. To improve map comparability we introduced elements of spatial and thematic fuzzy logic. The project results show sufficient quality results for forest and dryland ecosystems, but can hardly provide stable results for other ecosystems.

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

    PubMed

    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. PMID:26003209

  5. Alpha and beta diversity of plants and animals along a tropical land-use gradient.

    PubMed

    Kessler, Michael; Abrahamczyk, Stefan; Bos, Merijn; Buchori, Damayanti; Putra, Dadang Dwi; Gradstein, S Robbert; Höhn, Patrick; Kluge, Jürgen; Orend, Friederike; Pitopang, Ramadhaniel; Saleh, Shahabuddin; Schulze, Christian H; Sporn, Simone G; Steffan-Dewenter, Ingolf; Tjitrosoedirdjo, Sri S; Tscharntke, Teja

    2009-12-01

    Assessing the overall biological diversity of tropical rain forests is a seemingly insurmountable task for ecologists. Therefore, researchers frequently sample selected taxa that they believe reflect general biodiversity patterns. Usually, these studies focus on the congruence of alpha diversity (the number of species found per sampling unit) between taxa rather than on beta diversity (turnover of species assemblages between sampling units). Such approaches ignore the potential role of habitat heterogeneity that, depending on the taxonomic group considered, can greatly enhance beta diversity at local and landscape scales. We compared alpha and beta diversity of four plant groups (trees, lianas, terrestrial herbs, epiphytic liverworts) and eight animal groups (birds, butterflies, lower canopy ants, lower canopy beetles, dung beetles, bees, wasps, and the parasitoids of the latter two) at 15 sites in Sulawesi, Indonesia, that represented natural rain forest and three types of cacao agroforests differing in management intensity. In total, we recorded 863 species. Patterns of species richness per study site varied strongly between taxonomic groups. Only 13-17% of the variance in species richness of one taxonomic group could be predicted from the species richness of another, and on average 12-18% of the variance of beta diversity of a given group was predicted by that in other groups, although some taxon pairs had higher values (up to 76% for wasps and their parasitoids). The degree of congruence of patterns of alpha diversity was not influenced by sampling completeness, whereas the indicator value for beta diversity improved when using a similarity index that accounts for incomplete sampling. The indication potential of alpha diversity for beta diversity and vice versa was limited within taxa (7-20%) and virtually nil between them (0-4%). We conclude that different taxa can have largely independent patterns of alpha diversity and that patterns of beta diversity can be more congruent. Thus, conservation plans on a landscape scale need to put more emphasis on the high heterogeneity of agroforests and the overarching role of beta diversity shaping overall diversity patterns. PMID:20014584

  6. Enhanced interannual precipitation variability increases plant functional diversity that in turn ameliorates negative impact on productivity.

    PubMed

    Gherardi, Laureano A; Sala, Osvaldo E

    2015-12-01

    Although precipitation interannual variability is projected to increase due to climate change, effects of changes in precipitation variance have received considerable less attention than effects of changes in the mean state of climate. Interannual precipitation variability effects on functional diversity and its consequences for ecosystem functioning are assessed here using a 6-year rainfall manipulation experiment. Five precipitation treatments were switched annually resulting in increased levels of precipitation variability while maintaining average precipitation constant. Functional diversity showed a positive response to increased variability due to increased evenness. Dominant grasses decreased and rare plant functional types increased in abundance because grasses showed a hump-shaped response to precipitation with a maximum around modal precipitation, whereas rare species peaked at high precipitation values. Increased functional diversity ameliorated negative effects of precipitation variability on primary production. Rare species buffered the effect of precipitation variability on the variability in total productivity because their variance decreases with increasing precipitation variance. PMID:26437913

  7. Diversity, classification and function of the plant protein kinase superfamily

    PubMed Central

    Lehti-Shiu, Melissa D.; Shiu, Shin-Han

    2012-01-01

    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. PMID:22889912

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

    PubMed

    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 <1% of its total 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. PMID:17181815

  9. Plant and algal cell walls: diversity and functionality

    PubMed Central

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

    2014-01-01

    Background 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. Scope 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 and algal physiology that will present many of the major challenges in future cell wall research. PMID:25453142

  10. Plant and bird diversity in natural forests and in native and exotic plantations in NW Portugal

    NASA Astrophysics Data System (ADS)

    Proença, Vânia M.; Pereira, Henrique M.; Guilherme, João; Vicente, Luís

    2010-03-01

    Forest ecosystems have been subjected to continuous dynamics between deforestation and forestation. Assessing the effects of these processes on biodiversity could be essential for conservation planning. We analyzed patterns of species richness, diversity and evenness of plants and birds in patches of natural forest of Quercus spp. and in stands of native Pinus pinaster and exotic Eucalyptus globulus in NW Portugal. We analyzed data of forest and non-forest species separately, at the intra-patch, patch and inter-patch scales. Forest plant richness, diversity and evenness were higher in oak forest than in pine and eucalypt plantations. In total, 52 species of forest plants were observed in oak forest, 33 in pine plantation and 28 in eucalypt plantation. Some forest species, such as Euphorbia dulcis, Omphalodes nitida and Eryngium juresianum, were exclusively or mostly observed in oak forest. Forest bird richness and diversity were higher in both oak and pine forests than in eucalypt forest; evenness did not differ among forests. In total, 16 species of forest birds were observed in oak forest, 18 in pine forest and 11 in eucalypt forest. Species such as Certhia brachydactyla, Sitta europaea and Dendrocopos major were common in oak and/or pine patches but were absent from eucalypt stands. Species-area relationships of forest plants and forest birds in oak patches had consistently a higher slope, at both the intra and inter-patch scales, than species-area relationships of forest species in plantations and non-forest species in oak forest. These findings demonstrate the importance of oak forest for the conservation of forest species diversity, pointing the need to conserve large areas of oak forest due to the apparent vulnerability of forest species to area loss. Additionally, diversity patterns in pine forest were intermediate between oak forest and eucalypt forest, suggesting that forest species patterns may be affected by forest naturalness.

  11. How generalist herbivores exploit belowground plant diversity in temperate grasslands

    PubMed Central

    Wallinger, Corinna; Staudacher, Karin; Schallhart, Nikolaus; Mitterrutzner, Evi; Steiner, Eva-Maria; Juen, Anita; Traugott, Michael

    2014-01-01

    Belowground herbivores impact plant performance, thereby inducing changes in plant community composition, which potentially leads to cascading effects onto higher trophic levels and ecosystem processes and productivity. Among soil-living insects, external root-chewing generalist herbivores have the strongest impact on plants. However, the lack of knowledge on their feeding behaviour under field conditions considerably hampers achieving a comprehensive understanding of how they affect plant communities. Here, we address this gap of knowledge by investigating the feeding behaviour of Agriotes click beetle larvae, which are common generalist external root-chewers in temperate grassland soils. Utilizing diagnostic multiplex PCR to assess the larval diet, we examined the seasonal patterns in feeding activity, putative preferences for specific plant taxa, and whether species identity and larval instar affect food choices of the herbivores. Contrary to our hypothesis, most of the larvae were feeding-active throughout the entire vegetation period, indicating that the grassland plants are subjected to constant belowground feeding pressure. Feeding was selective, with members of Plantaginaceae and Asteraceae being preferred; Apiaceae were avoided. Poaceae, although assumed to be most preferred, had an intermediate position. The food preferences exhibited seasonal changes, indicating a fluctuation in plant traits important for wireworm feeding choice. Species- and instar-specific differences in dietary choice of the Agriotes larvae were small, suggesting that species and larval instars occupy the same trophic niche. According to the current findings, the food choice of these larvae is primarily driven by plant identity, exhibiting seasonal changes. This needs to be considered when analysing soil herbivore–plant interactions. PMID:24188592

  12. Diversity cascades in alfalfa fields: from plant quality to agroecosystem diversity.

    PubMed

    Pearson, Clark V; Massad, Tara J; Dyer, Lee A

    2008-08-01

    To examine top-down and bottom-up influences on managed terrestrial communities, we manipulated plant resources and arthropod abundance in alfalfa (Medicago sativa L.) fields. We modified arthropod communities using three nonfactorial manipulations: pitfall traps to remove selected arthropods, wooden crates to create habitat heterogeneity, and an arthropod removal treatment using a reversible leaf blower. These manipulations were crossed with fertilizer additions, which were applied to half of the plots. We found strong effects of fertilizer on plant quality and biomass, and these effects cascaded up to increase herbivore abundance and diversity. The predator community also exhibited a consistent positive effect on the maintenance of herbivore species richness and abundance. These top-down changes in arthropods did not cascade down to affect plant biomass; however, plant quality (saponin content) increased with higher herbivore densities. These results corroborate previous studies in alfalfa that show complex indirect effects, such as trophic cascades, can operate in agricultural systems, but the specifics of the interactions depend on the assemblages of arthropods involved. PMID:18801260

  13. Promontory Facility Plant-wide Energy Assessment

    SciTech Connect

    Weir, Roger M.; Bebb, Deanna, Brown, Herman E.

    2008-03-28

    A 1-year plant-wide assessment at the ATK Promontory manufacturing facility utilizing innovative assessment technologies to identify energy savings opportunities in: steam, water, compressed air, HVAC, utility, production, and building systems.

  14. Plant diversity drives soil microbial biomass carbon in grasslands irrespective of global environmental change factors.

    PubMed

    Thakur, Madhav Prakash; Milcu, Alexandru; Manning, Pete; Niklaus, Pascal A; Roscher, Christiane; Power, Sally; Reich, Peter B; Scheu, Stefan; Tilman, David; Ai, Fuxun; Guo, Hongyan; Ji, Rong; Pierce, Sarah; Ramirez, Nathaly Guerrero; Richter, Annabell Nicola; Steinauer, Katja; Strecker, Tanja; Vogel, Anja; Eisenhauer, Nico

    2015-11-01

    Soil microbial biomass is a key determinant of carbon dynamics in the soil. Several studies have shown that soil microbial biomass significantly increases with plant species diversity, but it remains unclear whether plant species diversity can also stabilize soil microbial biomass in a changing environment. This question is particularly relevant as many global environmental change (GEC) factors, such as drought and nutrient enrichment, have been shown to reduce soil microbial biomass. Experiments with orthogonal manipulations of plant diversity and GEC factors can provide insights whether plant diversity can attenuate such detrimental effects on soil microbial biomass. Here, we present the analysis of 12 different studies with 14 unique orthogonal plant diversity × GEC manipulations in grasslands, where plant diversity and at least one GEC factor (elevated CO2 , nutrient enrichment, drought, earthworm presence, or warming) were manipulated. Our results show that higher plant diversity significantly enhances soil microbial biomass with the strongest effects in long-term field experiments. In contrast, GEC factors had inconsistent effects with only drought having a significant negative effect. Importantly, we report consistent non-significant effects for all 14 interactions between plant diversity and GEC factors, which indicates a limited potential of plant diversity to attenuate the effects of GEC factors on soil microbial biomass. We highlight that plant diversity is a major determinant of soil microbial biomass in experimental grasslands that can influence soil carbon dynamics irrespective of GEC. PMID:26118993

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

    PubMed

    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. PMID:25084653

  16. Soil stability and plant diversity in eco-engineering

    NASA Astrophysics Data System (ADS)

    Böll, Albert; Gerber, Werner; Rickli, Christian; Graf, Frank

    2010-05-01

    Slopes affected by superficial sliding and subsequently re-stabilised with eco-engineering measures were investigated, particularly related to soil stability and plant diversity. The sites are situated in three different areas of beech-fir-spruce forest associations of the higher montane zone of Switzerland. Climatic and site characteristics, in paraticular soil properties after the sliding event, of the three investigation areas are very similar. However, the number of species (shrubs and trees) used for the initial planting as well as the year of application of the eco-engineering measures differ substantially. In the investigation area Dallenwil-Wirzweli the biological measures taken in 1981 were restricted to one tree species, namely White Alder (Alnus incana). In Klosters, where measures were taken in 1983 as well as in the Arieschbach valley, where eco-engineering was applied in 1998, the initial planting consisted of 15 species either. Investigations in 2005/2006 revealed neither obvious differences among the three areas nor distinct correlations related to the diversity of the initial planting on the on hand and the development of the vegetation cover and soil stability on the other hand. During the available time of development, the soil aggregate stability increased by 30 to 39%. Compared to the corresponding climax association, the relative values of soil aggregate stability varied between 90 and 120%. Concurrently, the dry unit weight decreased between 1.1 and 3.1 kN/m3. The cumulative vegetation cover varied from 110 to 150%. Due to processes of soil development a distinct shift in the grain size distribution was noticed, from a well sorted gravel with clay and sand (GW-GC) to a silty gravel with sand (GM) in Dallenwil-Wirzweli and a silty to clayey gravel with sand (GC-GM) in Klosters and the Arieschbach valley. Furthermore, in all three investigation areas succession processes were observed that are comparable to average rates of natural secondary succession. The number of shrub and tree species recorded in 2005/2006 varied between 12 and 16. According to the recommendations for silvicultural maintenance of protective forests, the shrub- and tree layer consisted of 75 to 100% of the required plant species in view of the potential target association.

  17. Impacts of weather on long-term patterns of plant richness and diversity vary with location and management

    USGS Publications Warehouse

    Jonas, Jayne L.; Buhl, Deborah A.; Symstad, Amy J.

    2015-01-01

    Better understanding the influence of precipitation and temperature on plant assemblages is needed to predict the effects of climate change. Many studies have examined the relationship between plant productivity and weather (primarily precipitation), but few have directly assessed the relationship between plant richness or diversity and weather despite their increased use as metrics of ecosystem condition. We focus on the grasslands of central North America, which are characterized by high temporal climatic variability. Over the next 100 years, these grasslands are predicted to experience further increased variability in growing season precipitation, as well as increased temperatures, due to global climate change. We assess 1) the portion of interannual variability of richness and diversity explained by weather, 2) how relationships between these metrics and weather vary among plant assemblages, and 3) which aspects of weather best explain temporal variability. We used an information-theoretic approach to assess relationships between long-term plant richness and diversity patterns and a priori weather covariates using six datasets from four grasslands. Weather explained up to 49% and 63% of interannual variability in total plant species richness and diversity, respectively. However, richness and diversity responses to specific weather variables varied both among sites and among experimental treatments within sites. In general, we found many instances in which temperature was of equal or greater importance as precipitation, as well as evidence of the importance of lagged effects and precipitation or temperature variability. Although precipitation has been shown to be a key driver of productivity in grasslands, our results indicate that increasing temperatures alone, without substantial changes in precipitation patterns, could have measurable effects on Great Plains grassland plant assemblages and biodiversity metrics. Our results also suggest that richness and diversity will respond in unique ways to changing climate and management can affect these responses; additional research and monitoring will be essential for further understanding of these complex relationships.Read More: http://www.esajournals.org/doi/abs/10.1890/14-1989.1

  18. Impacts of weather on long-term patterns of plant richness and diversity vary with location and management.

    PubMed

    Jonas, Jayne L; Buhl, Deborah A; Symstad, Amy J

    2015-09-01

    Better understanding the influence of precipitation and temperature on plant assemblages is needed to predict the effects of climate change. Many studies have examined the relationship between plant productivity and weather (primarily precipitation), but few have directly assessed the relationship between plant richness or diversity and weather despite their increased use as metrics of ecosystem condition. We focus on the grasslands of central North America, which are characterized by high temporal climatic variability. Over the next 100 years, these grasslands are predicted to experience further increased variability in growing season precipitation, as well as increased temperatures, due to global climate change. We assess the portion of interannual variability of richness and diversity explained by weather, how relationships between these metrics and weather vary among plant assemblages, and which aspects of weather best explain temporal variability. We used an information-theoretic approach to assess relationships between long-term plant richness and diversity patterns and a priori weather covariates using six data sets from four grasslands. Weather explained up to 49% and 63% of interannual variability in total plant species richness and diversity, respectively. However, richness and diversity responses to specific weather variables varied both among sites and among experimental treatments within sites. In general, we found many instances in which temperature was of equal or greater importance as precipitation, as well as evidence of the importance of lagged effects and precipitation or temperature variability. Although precipitation has been shown to be a key driver of productivity in grasslands, our results indicate that increasing temperatures alone, without substantial changes in precipitation patterns, could have measurable effects on Great Plains grassland plant assemblages and biodiversity metrics. Our results also suggest that richness and diversity will respond in unique ways to changing climate and management can affect these responses; additional research and monitoring will be essential for further understanding of these complex relationships. PMID:26594699

  19. Application of diversity to regional ecological assessment: a review with recommendations

    SciTech Connect

    Levenson, J.B.; Stearns, F.W.

    1980-03-01

    Species diversity is frequently considered a primary indicator of ecosystem health, stability, and resilience. As such, species diversity is commonly the major criterion upon which environmental impact statements and ecological assessments are based. This report describes the theoretical development and refinement of the concept of ecological diversity and the various mathematical expressions of diversity. Advantages and disadvantages of each diversity expression are discussed. The application and interpretation of diversity indices for different spatial scales (e.g., specific sites and regional assessments) and variables (e.g., species diversity, habitat diversity, landscape diversity) are contrasted. Recommendations indicate the appropriate diversity indices for regional ecological assessments.

  20. Genomic diversity of Pseudomonas spp. isolated from aerial or root surfaces of plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among the diverse strains of Pseudomonas fluorescens and Pseudomonas chlororaphis inhabiting plant surfaces are those that protect plants from infection by pathogens. To explore the diversity of these bacteria, we derived genomic sequences of seven strains that suppress plant disease. Along with t...

  1. Diversity in plants and other Collembola ameliorate impacts of Sminthurus viridis on plant community structure

    NASA Astrophysics Data System (ADS)

    Barker, Gary M.

    2006-05-01

    Five experiments investigated the importance of herbivory by Sminthurus viridis in structuring botanical composition in developing grasslands, and how these effects may be modified by diversity in collembolan and plant species. Differential susceptibility to S. viridis feeding was demonstrated in 23 dicotyledonous and three monocotyledonous plants assayed as seedlings at the first true leaf stage. The composition of seedling communities developing from natural and artificially constructed soil seed banks varied with the level of S. viridis infestation, with plant species least susceptible to herbivory making the greatest contribution to plant biomass. The combined effect of herbivory by S. viridis and Bourletiella hortensis on Trifolium repens biomass was shown to be less than the effect of S. viridis alone, indicating competitive interference. The adverse effects of herbivory by S. viridis on T. repens biomass was reduced by increased diversity of plants growing in association with the legume, and the presence of four non-herbivorous arthropleonan Collembola. S. viridis was shown to reduce seedling numbers, species diversity and biomass in communities developing from the soil seed bank, but the presence of non-herbivorous arthropleonan species reduced the effect of S. viridis. The experiments demonstrate the potential for herbivory by S. viridis to significantly alter species composition in developing grassland communities. However, interactions with collembolan and plant species profoundly modified S. viridis herbivory impacts, either by reducing feeding intensity or enhancing plant growth. These results highlight the fact that data from simple, synthetic systems may be poor predictors of herbivory impacts under field conditions where more complex species interactions occur.

  2. Development and Initial Psychometric Assessment of the Plant Attitude Questionnaire

    NASA Astrophysics Data System (ADS)

    Fan?ovi?ová, Jana; Prokop, Pavol

    2010-10-01

    Plants are integral parts of ecosystems which determine life on Earth. People's attitudes toward them are however, largely overlooked. Here we present initial psychometric assessment of self-constructed Plant Attitude Scale (PAS) that was administered to a sample of 310 Slovakian students living in rural areas aged 10-15 years. The final version of PAS consists from 29 Likert-scale items that were loaded to four distinct dimensions (Interest, Importance, Urban trees and Utilization). Mean scores revealed that Slovakian students lack positive attitudes toward plants and that gender had no effect on their mean attitude scores. Living in a family with a garden was associated with a more positive attitude toward plants. Further correlative research on diverse samples containing urban children and experimental research examining the impact of gardening in schools on student attitudes toward plants is required.

  3. Bacterial diversity and composition in the fluid of pitcher plants of the genus Nepenthes.

    PubMed

    Takeuchi, Yayoi; Chaffron, Samuel; Salcher, Michaela M; Shimizu-Inatsugi, Rie; Kobayashi, Masaki J; Diway, Bibian; von Mering, Christian; Pernthaler, Jakob; Shimizu, Kentaro K

    2015-07-01

    Pitchers are modified leaves used by carnivorous plants for trapping prey. Their fluids contain digestive enzymes from the plant and they harbor abundant microbes. In this study, the diversity of bacterial communities was assessed in Nepenthes pitcher fluids and the composition of the bacterial community was compared to that in other environments, including the phyllosphere of Arabidopsis, animal guts and another pitcher plant, Sarracenia. Diversity was measured by 454 pyrosequencing of 16S rRNA gene amplicons. A total of 232,823 sequences were obtained after chimera and singleton removal that clustered into 3260 distinct operational taxonomic units (OTUs) (3% dissimilarity), which were taxonomically distributed over 17 phyla, 25 classes, 45 orders, 100 families, and 195 genera. Pyrosequencing and fluorescence in situ hybridization yielded similar estimates of community composition. Most pitchers contained high proportions of unique OTUs, and only 22 OTUs (<0.6%) were shared by ≥14/16 samples, suggesting a unique bacterial assemblage in each pitcher at the OTU level. Diversity analysis at the class level revealed that the bacterial communities of both opened and unopened pitchers were most similar to that of Sarracenia and to that in the phyllosphere. Therefore, the bacterial community in pitchers may be formed by environmental filtering and/or by phyllosphere bacteria. PMID:26138047

  4. Plant diversity effects on aboveground and belowground N pools in temperate grassland ecosystems: Development in the first 5 years after establishment

    NASA Astrophysics Data System (ADS)

    Oelmann, Yvonne; Buchmann, Nina; Gleixner, Gerd; Habekost, Maike; Roscher, Christiane; Rosenkranz, Stephan; Schulze, Ernst-Detlef; Steinbeiss, Sibylle; Temperton, Vicky M.; Weigelt, Alexandra; Weisser, Wolfgang W.; Wilcke, Wolfgang

    2011-06-01

    Biodiversity is expected to improve ecosystem services, e.g., productivity or seepage water quality. The current view of plant diversity effects on element cycling is based on short-term grassland studies that discount possibly slow belowground feedbacks to aboveground diversity. Furthermore, these grasslands were established on formerly arable land associated with changes in soil properties, e.g., accumulation of organic matter. We hypothesize that the plant diversity-N cycle relationship changes with time since establishment. We assessed the relationship between plant diversity and (1) aboveground and soil N storage and (2) NO3-N and NH4-N availability in soil between 2003 and 2007 in the Jena Experiment, a grassland experiment established in 2002 in which the number of plant species varied from 1 to 60. The positive effect of plant diversity on aboveground N storage (mainly driven by biomass production) tended to increase through time. The initially negative correlation between plant diversity and soil NO3-N availability disappeared after 2003. In 2006 and 2007, a positive correlation between plant diversity and soil NH4-N availability appeared which coincided with a positive correlation between plant diversity and N mineralized from total N accumulated in soil. We conclude that the plant diversity-N cycle relationship in newly established grasslands changes with time because of accumulation of organic matter in soil associated with the establishment. While a positive relationship between plant diversity and soil N storage improves soil fertility and reduces fertilizing needs, increasingly closed N cycling with increasing plant diversity as illustrated by decreased NO3-N concentrations in diverse mixtures reduces the negative impact of agricultural N leaching on groundwater resources.

  5. Long-term effects of sowing high or low diverse seed mixtures on plant and gastropod diversity

    NASA Astrophysics Data System (ADS)

    Dedov, Ivailo; Stoyanov, Ivailo L.; Penev, Lyubomir; Harvey, Jeffrey A.; Van der Putten, Wim H.; Bezemer, T. Martijn

    2006-09-01

    A number of studies have reported that consumers affect a range of community-level processes, and in turn their diversity and abundance is influenced by the structure and diversity of the plant community. Although gastropods are important generalist herbivores in many environments, few studies have examined the effects of plant species richness and plant community structure on gastropods. This study investigated gastropod species richness and interactions with various above-ground parameters of the vegetation on an experimental field with four plant treatments: low and high diversity of sown later succession plant species, natural colonization at the start of the experiment and natural colonization after 3 years of continued agricultural practice. The investigated gastropod assemblage contained only seven species and was highly dominated by two of them. Both in pitfalls and with hand-sorting the number of species collected per plot was highest in plots with natural plant colonization. Multivariate analysis revealed that overall gastropod abundance was positively associated with plant height and percentage cover of plants, and negatively with percentage grass cover. The same pattern holds for one of the dominant species-complex ( Cochlicopa lubrica/ lubricella). The other dominant gastropod species ( Deroceras reticulatum) was more abundant in samples with higher percentages of moss cover and higher plant diversity, while less abundant at samples with higher plant cover, indicating that the gastropod species preferences may matter more than just their response to plant diversity. Two plant-gastropod species-level associations were observed: Senecio jacobaea with D. reticulatum and Tanacetum vulgare with Cochlicopa spp. The present study also demonstrated that pitfall-traps are suitable for collecting terrestrial gastropods, at least for species-poor grassland habitats.

  6. Assessing genetic diversity in Valencia peanut germplasm using SSR markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Valencia peanuts (Arachis hypogaea L.ssp. fastigiata var. fastigiata) are well known for their in-shell market value. Assessment of genetic diversity of the available Valencia germplasm is key to the success of developing improved cultivars with desirable agronomic and quality traits. In the pres...

  7. New Teacher Standards and Learner Diversity: Ideas for Authentic Assessment.

    ERIC Educational Resources Information Center

    Moore, John; Benton, Janet

    Changing views about learning and schooling affect teacher preparation programs. The paper examines how Kentucky's standards for new teachers relate to addressing learner diversity, explaining how the Kentucky Education Reform Act is a model for affecting statewide change, particularly regarding methods of assessment and examination of learner…

  8. Assessment of a Diversity Assignment in a PR Principles Course

    ERIC Educational Resources Information Center

    Gallicano, Tiffany Derville; Stansberry, Kathleen

    2012-01-01

    This study assesses an assignment for incorporating diversity into the principles of public relations course. The assignment is tailored to the challenges of using an active learning approach in a large lecture class. For the assignment, students write a goal, objectives, strategies, an identification of tactics, and evaluation plans for either…

  9. Psychometric Evaluation of Lexical Diversity Indices: Assessing Length Effects

    ERIC Educational Resources Information Center

    Fergadiotis, Gerasimos; Wright, Heather Harris; Green, Samuel B.

    2015-01-01

    Purpose: Several novel techniques have been developed recently to assess the breadth of a speaker's vocabulary exhibited in a language sample. The specific aim of this study was to increase our understanding of the validity of the scores generated by different lexical diversity (LD) estimation techniques. Four techniques were explored: D, Maas,…

  10. Assessment of a Diversity Assignment in a PR Principles Course

    ERIC Educational Resources Information Center

    Gallicano, Tiffany Derville; Stansberry, Kathleen

    2012-01-01

    This study assesses an assignment for incorporating diversity into the principles of public relations course. The assignment is tailored to the challenges of using an active learning approach in a large lecture class. For the assignment, students write a goal, objectives, strategies, an identification of tactics, and evaluation plans for either…

  11. Assessment of genetic diversity of sweet potato in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweet potato (Ipomoea batatas L.) is the seventh most important food crop due to its distinct advantages, such as adaptability to different environmental conditions and high nutritional value. Assessing the genetic diversity of this important crop is necessary due to the constant increase of demand ...

  12. Tiger Team assessment of the Pinellas Plant

    SciTech Connect

    Not Available

    1990-05-01

    This Document contains findings identified during the Tiger Team Compliance Assessment of the Department of Energy's (DOE's) Pinellas Plant, Pinellas County, Florida. The assessment wa directed by the Department's Office of Environment, Safety, and Health (ES H) from January 15 to February 2, 1990. The Pinellas Tiger Team Compliance Assessment is comprehensive in scope. It covers the Environment Safety and Health, and Management areas and determines the plant's compliance with applicable Federal (including DOE), State, and local regulations and requirements.

  13. Diversity and use of ethno-medicinal plants in the region of Swat, North Pakistan

    PubMed Central

    2013-01-01

    Background Due to its diverse geographical and habitat conditions, northern Pakistan harbors a wealth of medicinal plants. The plants and their traditional use are part of the natural and cultural heritage of the region. This study was carried out to document which medicinal plant species and which plant parts are used in the region of Swat, which syndrome categories are particularly concerned, and which habitat spectrum is frequented by collectors. Finally, we assessed to which extent medicinal plants are vulnerable due to collection and habitat destruction. Methods An ethnobotanical survey was undertaken in the Miandam area of Swat, North Pakistan. Data were collected through field assessment as well as from traditional healers and locals by means of personal interviews and semi-structured questionnaires. Results A total of 106 ethno-medicinal plant species belonging to 54 plant families were recorded. The most common growth forms were perennial (43%) and short-lived herbs (23%), shrubs (16%), and trees (15%). Most frequently used plant parts were leaves (24%), fruits (18%) and subterranean parts (15%). A considerable proportion of the ethno-medicinal plant species and remedies concerns gastro-intestinal disorders. The remedies were mostly prepared in the form of decoction or powder and were mainly taken orally. Eighty out of 106 ethno-medicinal plants were indigenous. Almost 50% of the plants occurred in synanthropic vegetation while slightly more than 50% were found in semi-natural, though extensively grazed, woodland and grassland vegetation. Three species (Aconitum violaceum, Colchicum luteum, Jasminum humile) must be considered vulnerable due to excessive collection. Woodlands are the main source for non-synanthropic indigenous medicinal plants. The latter include many range-restricted taxa and plants of which rhizomes and other subterranean parts are dug out for further processing as medicine. Conclusion Medicinal plants are still widely used for treatment in the area of Swat. Some species of woodlands seem to be adapted to wood-pasture, but vulnerable to overcollecting, and in particular to deforestation. It is suggested to implement local small-scaled agroforestry systems to cultivate vulnerable and commercially valuable ethno-medicinal woodland plants under local self-government responsibility. PMID:23587127

  14. Functional trait diversity across trophic levels determines herbivore impact on plant community biomass.

    PubMed

    Deraison, Hélène; Badenhausser, Isabelle; Loeuille, Nicolas; Scherber, Christoph; Gross, Nicolas

    2015-12-01

    Understanding the consequences of trophic interactions for ecosystem functioning is challenging, as contrasting effects of species and functional diversity can be expected across trophic levels. We experimentally manipulated functional identity and diversity of grassland insect herbivores and tested their impact on plant community biomass. Herbivore resource acquisition traits, i.e. mandible strength and the diversity of mandibular traits, had more important effects on plant biomass than body size. Higher herbivore functional diversity increased overall impact on plant biomass due to feeding niche complementarity. Higher plant functional diversity limited biomass pre-emption by herbivores. The functional diversity within and across trophic levels therefore regulates the impact of functionally contrasting consumers on primary producers. By experimentally manipulating the functional diversity across trophic levels, our study illustrates how trait-based approaches constitute a promising way to tackle existing links between trophic interactions and ecosystem functioning. PMID:26439435

  15. Higher effect of plant species diversity on productivity in natural than artificial ecosystems

    PubMed Central

    Flombaum, Pedro; Sala, Osvaldo E.

    2008-01-01

    Current and expected changes in biodiversity have motivated major experiments, which reported a positive relationship between plant species diversity and primary production. As a first step in addressing this relationship, these manipulative experiments controlled as many potential confounding covariables as possible and assembled artificial ecosystems for the purpose of the experiments. As a new step in this endeavor, we asked how plant species richness relates to productivity in a natural ecosystem. Here, we report on an experiment conducted in a natural ecosystem in the Patagonian steppe, in which we assessed the biodiversity effect on primary production. Using a plant species diversity gradient generated by removing species while maintaining constant biomass, we found that aboveground net primary production increased with the number of plant species. We also found that the biodiversity effect was larger in natural than in artificial ecosystems. This result supports previous findings and also suggests that the effect of biodiversity in natural ecosystems may be much larger than currently thought. PMID:18427124

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

    PubMed

    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. PMID:24816860

  17. Biotic and Abiotic Properties Mediating Plant Diversity Effects on Soil Microbial Communities in an Experimental Grassland

    PubMed Central

    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. PMID:24816860

  18. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants.

    PubMed

    Brummitt, Neil A; Bachman, Steven P; Griffiths-Lee, Janine; Lutz, Maiko; Moat, Justin F; Farjon, Aljos; Donaldson, John S; Hilton-Taylor, Craig; Meagher, Thomas R; Albuquerque, Sara; Aletrari, Elina; Andrews, A Kei; Atchison, Guy; Baloch, Elisabeth; Barlozzini, Barbara; Brunazzi, Alice; Carretero, Julia; Celesti, Marco; Chadburn, Helen; Cianfoni, Eduardo; Cockel, Chris; Coldwell, Vanessa; Concetti, Benedetta; Contu, Sara; Crook, Vicki; Dyson, Philippa; Gardiner, Lauren; Ghanim, Nadia; Greene, Hannah; Groom, Alice; Harker, Ruth; Hopkins, Della; Khela, Sonia; Lakeman-Fraser, Poppy; Lindon, Heather; Lockwood, Helen; Loftus, Christine; Lombrici, Debora; Lopez-Poveda, Lucia; Lyon, James; Malcolm-Tompkins, Patricia; McGregor, Kirsty; Moreno, Laura; Murray, Linda; Nazar, Keara; Power, Emily; Quiton Tuijtelaars, Mireya; Salter, Ruth; Segrott, Robert; Thacker, Hannah; Thomas, Leighton J; Tingvoll, Sarah; Watkinson, Gemma; Wojtaszekova, Katerina; Nic Lughadha, Eimear M

    2015-01-01

    Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question 'How threatened are plants?' is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world's plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed. PMID:26252495

  19. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants

    PubMed Central

    Griffiths-Lee, Janine; Lutz, Maiko; Moat, Justin F.; Farjon, Aljos; Donaldson, John S.; Hilton-Taylor, Craig; Meagher, Thomas R.; Albuquerque, Sara; Aletrari, Elina; Andrews, A. Kei; Atchison, Guy; Baloch, Elisabeth; Barlozzini, Barbara; Brunazzi, Alice; Carretero, Julia; Celesti, Marco; Chadburn, Helen; Cianfoni, Eduardo; Cockel, Chris; Coldwell, Vanessa; Concetti, Benedetta; Contu, Sara; Crook, Vicki; Dyson, Philippa; Gardiner, Lauren; Ghanim, Nadia; Greene, Hannah; Groom, Alice; Harker, Ruth; Hopkins, Della; Khela, Sonia; Lakeman-Fraser, Poppy; Lindon, Heather; Lockwood, Helen; Loftus, Christine; Lombrici, Debora; Lopez-Poveda, Lucia; Lyon, James; Malcolm-Tompkins, Patricia; McGregor, Kirsty; Moreno, Laura; Murray, Linda; Nazar, Keara; Power, Emily; Quiton Tuijtelaars, Mireya; Salter, Ruth; Segrott, Robert; Thacker, Hannah; Thomas, Leighton J.; Tingvoll, Sarah; Watkinson, Gemma; Wojtaszekova, Katerina; Nic Lughadha, Eimear M.

    2015-01-01

    Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question ‘How threatened are plants?’ is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world’s plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed. PMID:26252495

  20. Plant and soil responses to high and low diversity grassland restoration practices.

    PubMed

    Bach, Elizabeth M; Baer, Sara G; Six, Johan

    2012-02-01

    The USDA's Conservation Reserve Program (CRP) has predominantly used only a few species of dominant prairie grasses (CP2 practice) to reduce soil erosion, but recently has offered a higher diversity planting practice (CP25) to increase grassland habitat quality. We quantified plant community composition in CP25 and CP2 plantings restored for 4 or 8 years and compared belowground properties and processes among restorations and continuously cultivated soils in southeastern Nebraska, USA. Relative to cultivated soils, restoration increased soil microbial biomass (P = 0.033), specifically fungi (P < 0.001), and restored soils exhibited higher rates of carbon (C) mineralization (P = 0.010). High and low diversity plantings had equally diverse plant communities; however, CP25 plantings had greater frequency of cool-season (C(3)) grasses (P = 0.007). Older (8 year) high diversity restorations contained lower microbial biomass (P = 0.026), arbuscular mycorrhizal fungi (AMF) biomass (P = 0.003), and C mineralization rates (P = 0.028) relative to 8 year low diversity restorations; older plantings had greater root biomass than 4 year plantings in all restorations (P = 0.001). Low diversity 8 year plantings contained wider root C:N ratios, and higher soil microbial biomass, microbial community richness, AMF biomass, and C mineralization rate relative to 4 year restorations (P < 0.050). Net N mineralization and nitrification rates were lower in 8 year than 4 year high diversity plantings (P = 0.005). We attributed changes in soil C and N pools and fluxes to increased AMF associated with C(4) grasses in low diversity plantings. Thus, reduced recovery of AMF in high diversity plantings restricted restoration of belowground microbial diversity and microbially-mediated soil processes over time. PMID:22105609

  1. Assessing and broadening genetic diversity of a rapeseed germplasm collection.

    PubMed

    Wu, Jinfeng; Li, Feng; Xu, Kun; Gao, Guizhen; Chen, Biyun; Yan, Guixin; Wang, Nian; Qiao, Jiangwei; Li, Jun; Li, Hao; Zhang, Tianyao; Song, Weiling; Wu, Xiaoming

    2014-12-01

    Assessing the level of genetic diversity within a germplasm collection contributes to evaluating the potential for its utilization as a gene pool to improve the performance of cultivars. In this study, 45 high-quality simple sequence repeat (SSR) markers were screened and used to estimate the genetic base of a world-wide collection of 248 rapeseed (Brassica napus) inbred lines. For the whole collection, the genetic diversity of A genome was higher than that of C genome. The genetic diversity of C genome for the semi-winter type was the lowest among the different germplasm types. Because B. oleracea is usually used to broaden the genetic diversity of C genome in rapeseed, we evaluated the potential of 25 wild B. oleracea lines. More allelic variations and a higher genetic diversity were observed in B. oleracea than in rapeseed. One B. oleracea line and one oilseed B. rapa line were used to generate a resynthesized Brassica napus line, which was then crossed with six semi-winter rapeseed cultivars to produce 7 F1 hybrids. Not only the allele introgression but also mutations were observed in the hybrids, resulting in significant improvement of the genetic base. PMID:25914586

  2. AfroDb: A Select Highly Potent and Diverse Natural Product Library from African Medicinal Plants

    PubMed Central

    Ntie-Kang, Fidele; Zofou, Denis; Babiaka, Smith B.; Meudom, Rolande; Scharfe, Michael; Lifongo, Lydia L.; Mbah, James A.; Mbaze, Luc Meva’a; Sippl, Wolfgang; Efange, Simon M. N.

    2013-01-01

    Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. We assess the bioactivity and “drug-likeness” of a relatively small but structurally diverse dataset (containing >1,000 compounds) from African medicinal plants, which have been tested and proven a wide range of biological activities. The geographical regions of collection of the medicinal plants cover the entire continent of Africa, based on data from literature sources and information from traditional healers. For each isolated compound, the three dimensional (3D) structure has been used to calculate physico-chemical properties used in the prediction of oral bioavailability on the basis of Lipinski’s “Rule of Five”. A comparative analysis has been carried out with the “drug-like”, “lead-like”, and “fragment-like” subsets, as well as with the Dictionary of Natural Products. A diversity analysis has been carried out in comparison with the ChemBridge diverse database. Furthermore, descriptors related to absorption, distribution, metabolism, excretion and toxicity (ADMET) have been used to predict the pharmacokinetic profile of the compounds within the dataset. Our results prove that drug discovery, beginning with natural products from the African flora, could be highly promising. The 3D structures are available and could be useful for virtual screening and natural product lead generation programs. PMID:24205103

  3. Technology-Enhanced Formative Assessment of Plant Identification

    NASA Astrophysics Data System (ADS)

    Conejo, Ricardo; Garcia-Viñas, Juan Ignacio; Gastón, Aitor; Barros, Beatriz

    2015-10-01

    Developing plant identification skills is an important part of the curriculum of any botany course in higher education. Frequent practice with dried and fresh plants is necessary to recognize the diversity of forms, states, and details that a species can present. We have developed a web-based assessment system for mobile devices that is able to pose appropriate questions according to the location of the student. A student's location can be obtained using the device position or by scanning a QR code attached to a dried plant sheet in a herbarium or to a fresh plant in an arboretum. The assessment questions are complemented with elaborated feedback that, according to the students' responses, provides indications of possible mistakes and correct answers. Three experiments were designed to measure the effectiveness of the formative assessment using dried and fresh plants. Three questionnaires were used to evaluate the system performance from the students' perspective. The results clearly indicate that formative assessment is objectively effective compared to traditional methods and that the students' attitudes towards the system were very positive.

  4. Assessing Energy Use in Your Plant

    SciTech Connect

    2007-02-01

    This DOE Industrial Technologies Program fact sheet describes ITP resources and software that industrial plants can use for energy assessments that result in greater energy efficiency and lower costs.

  5. Plant diversity and identity effects on predatory nematodes and their prey.

    PubMed

    Kostenko, Olga; Duyts, Henk; Grootemaat, Saskia; De Deyn, Gerlinde B; Bezemer, T Martijn

    2015-02-01

    There is considerable evidence that both plant diversity and plant identity can influence the level of predation and predator abundance aboveground. However, how the level of predation in the soil and the abundance of predatory soil fauna are related to plant diversity and identity remains largely unknown. In a biodiversity field experiment, we examined the effects of plant diversity and identity on the infectivity of entomopathogenic nematodes (EPNs, Heterorhabditis and Steinernema spp.), which prey on soil arthropods, and abundance of carnivorous non-EPNs, which are predators of other nematode groups. To obtain a comprehensive view of the potential prey/food availability, we also quantified the abundance of soil insects and nonpredatory nematodes and the root biomass in the experimental plots. We used structural equation modeling (SEM) to investigate possible pathways by which plant diversity and identity may affect EPN infectivity and the abundance of carnivorous non-EPNs. Heterorhabditis spp. infectivity and the abundance of carnivorous non-EPNs were not directly related to plant diversity or the proportion of legumes, grasses and forbs in the plant community. However, Steinernema spp. infectivity was higher in monocultures of Festuca rubra and Trifolium pratense than in monocultures of the other six plant species. SEM revealed that legumes positively affected Steinernema infectivity, whereas plant diversity indirectly affected the infectivity of HeterorhabditisEPNs via effects on the abundance of soil insects. The abundance of prey (soil insects and root-feeding, bacterivorous, and fungivorous nematodes) increased with higher plant diversity. The abundance of prey nematodes was also positively affected by legumes. These plant community effects could not be explained by changes in root biomass. Our results show that plant diversity and identity effects on belowground biota (particularly soil nematode community) can differ between organisms that belong to the same feeding guild and that generalizations about plant diversity effects on soil organisms should be made with great caution. PMID:25750711

  6. Plant diversity and identity effects on predatory nematodes and their prey

    PubMed Central

    Kostenko, Olga; Duyts, Henk; Grootemaat, Saskia; De Deyn, Gerlinde B; Bezemer, T Martijn

    2015-01-01

    There is considerable evidence that both plant diversity and plant identity can influence the level of predation and predator abundance aboveground. However, how the level of predation in the soil and the abundance of predatory soil fauna are related to plant diversity and identity remains largely unknown. In a biodiversity field experiment, we examined the effects of plant diversity and identity on the infectivity of entomopathogenic nematodes (EPNs, Heterorhabditis and Steinernema spp.), which prey on soil arthropods, and abundance of carnivorous non-EPNs, which are predators of other nematode groups. To obtain a comprehensive view of the potential prey/food availability, we also quantified the abundance of soil insects and nonpredatory nematodes and the root biomass in the experimental plots. We used structural equation modeling (SEM) to investigate possible pathways by which plant diversity and identity may affect EPN infectivity and the abundance of carnivorous non-EPNs. Heterorhabditis spp. infectivity and the abundance of carnivorous non-EPNs were not directly related to plant diversity or the proportion of legumes, grasses and forbs in the plant community. However, Steinernema spp. infectivity was higher in monocultures of Festuca rubra and Trifolium pratense than in monocultures of the other six plant species. SEM revealed that legumes positively affected Steinernema infectivity, whereas plant diversity indirectly affected the infectivity of HeterorhabditisEPNs via effects on the abundance of soil insects. The abundance of prey (soil insects and root-feeding, bacterivorous, and fungivorous nematodes) increased with higher plant diversity. The abundance of prey nematodes was also positively affected by legumes. These plant community effects could not be explained by changes in root biomass. Our results show that plant diversity and identity effects on belowground biota (particularly soil nematode community) can differ between organisms that belong to the same feeding guild and that generalizations about plant diversity effects on soil organisms should be made with great caution. PMID:25750711

  7. Comparative assessment of genetic diversity among Indian bamboo genotypes using RAPD and ISSR markers.

    PubMed

    Desai, Parth; Gajera, Bhavesh; Mankad, Mounil; Shah, Shikha; Patel, Armi; Patil, Ghanshyam; Narayanan, Subhash; Kumar, Nitish

    2015-08-01

    Bamboo is one of the important plant for pulp, paper and charcoal industries. After China, India is the second largest bamboo reserve in Asia. Around the globe, wide genetic diversity of bamboo is present which serves as the base for selection and improvement. DNA based molecular markers appears to be a striking substitute for systematic assessment of the genetic diversity in conservation and genetic improvement of plants. DNA based molecular markers such as RAPD and ISSR were used to assess the genetic diversity in 13 bamboo genotypes. Total 120 RAPD and 63 ISSR primers were tested, of which only 42 polymorphic primers (30 RAPD and 12 ISSR), gave reproducible amplification profile and were used in this study. 30 RAPD primers yielded total 645 amplified fragments, of which 623 were polymorphic, and 20.76 polymorphic bands per primer were observed across 13 genotypes. 12 ISSR primers produced 246 amplified fragments, of which 241 were polymorphic, and 20.08 polymorphic bands per primer was observed across 13 different genotypes. The Jaccard's coefficient of RAPD, ISSR and pooled RAPD and ISSR dendrograms ranged from 0.26 to 0.83, 0.23 to 0.86 and 0.26 to 0.84 respectively. The present study found the large genetic diversity present between different elite genotypes of bamboo. Such investigation can deliver a well understanding of the available genotypes, which might be further exploited for the paper industry. PMID:25761883

  8. PLANT SPECIES DIVERSITY IN NATIVE AND RESTORED TALLGRASS PRAIRIES: PATTERNS AND CONTROLS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One goal of ecological restoration is to restore diversity of native vegetation, but mechanisms responsible for diversity in targeted communities often are poorly understood. We measured diversity (Simpson's index, 1/D) of plant species and functional groups of species in replicated 0.5-m2 plots wi...

  9. Effects of time since fire on birds in a plant diversity hotspot

    NASA Astrophysics Data System (ADS)

    Chalmandrier, Loïc; Midgley, Guy F.; Barnard, Phoebe; Sirami, Clélia

    2013-05-01

    Global changes are influencing fire regimes in many parts of the world. In the Fynbos plant diversity hotspot (Cape Floristic Region, South Africa), fire frequency has increased in protected areas where the mean fire interval went from 12-19 to 6-9 years between 1970 and 2000. Fire is one of the main drivers of plant diversity in the Cape Floristic Region. Too frequent fires threaten the persistence of slow-maturing plant species, and such insights have led to the adoption of fire management principles based on plant responses. The effects of fire on Fynbos fauna are much more poorly understood, and have not generally been considered in depth in Fynbos conservation policies, planning or management. We assessed the response of bird communities to long-term fire-induced vegetation changes using space-for-time substitution. We studied bird communities, vegetation structure and plant functional composition in 84 Fynbos plots burnt between two and 18 years before. Ten of the 14 bird species analysed showed a significant change in their abundance with time since fire. We observed a significant species turnover along the post-fire succession due to changes both in vegetation structure and plant functional composition, with a characteristic shift from non-Fynbos specialists and granivorous species to Fynbos specialists and nectarivorous species. If current trends of increasing fire frequency continue, Fynbos endemic birds such as nectarivores may become vulnerable. Conservation management should thus aim more carefully to maintain mosaics of Fynbos patches of different ages. Future research needs to estimate the proportion of vegetation of different ages and patch sizes needed to support dependent fauna, particularly endemics.

  10. Are herbage yield and yield stability affected by plant species diversity in sown pasture mixtures?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A tenet of plant biodiversity theory in grasslands is that increased diversity contributes to the stability of ecosystems. In managed grasslands, such as pastures, greater stability of herbage production as a result of increased plant species diversity would be beneficial. In this study, I combined ...

  11. RESTORING SPECIES RICHNESS AND DIVERSITY IN A RUSSIAN KNAPWEED-INFESTED RIPARIAN PLANT COMMUNITY USING HERBICIDES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species richness and diversity are important indicators of ecosystem function and may be related to plant community resistance to invasion by non-indigenous species. Knowledge about the influence of various strategies on species richness and diversity is central to making wise the invasive plant ma...

  12. Climate-suitable planting as a strategy for maintaining forest productivity and functional diversity.

    PubMed

    Duveneck, Matthew J; Scheller, Robert M

    2015-09-01

    Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000-2100) at a 2-ha cell resolution and five-year time steps within two landscapes in the Great Lakes region (northeastern Minnesota and northern lower Michigan, USA). We compared current climate to low- and high-emission futures. We simulated a low-emission climate future with the Intergovernmental Panel on Climate Change (IPCC) 2007 B1 emission scenario and the Parallel Climate Model Global Circulation Model (GCM). We simulated a high-emission climate future with the IPCC A1FI emission scenario and the Geophysical Fluid Dynamics Laboratory (GFDL) GCM. We compared current forest management practices (business-as-usual) to CSP management. In the CSP scenario, we simulated a target planting of 5.28% and 4.97% of forested area per five-year time step in the Minnesota and Michigan landscapes, respectively. We found that simulated CSP species successfully established in both landscapes under all climate scenarios. The presence of CSP species generally increased simulated aboveground biomass. Species diversity increased due to CSP; however, the effect on functional diversity was variable. Because the planted species were functionally similar to many native species, CSP did not result in a consistent increase nor decrease in functional diversity. These results provide an assessment of the potential efficacy and limitations of CSP management. These results have management implications for sites where diversity and productivity are expected to decline. Future efforts to restore a specific species or forest type may not be possible, but CSP may sustain a more general ecosystem service (e.g., aboveground biomass). PMID:26552272

  13. Island phytophagy: explaining the remarkable diversity of plant-feeding insects

    PubMed Central

    Joy, Jeffrey B.; Crespi, Bernard J.

    2012-01-01

    Plant-feeding insects have undergone unparalleled diversification among different plant taxa, yet explanations for variation in their diversity lack a quantitative, predictive framework. Island biogeographic theory has been applied to spatially discrete habitats but not to habitats, such as host plants, separated by genetic distance. We show that relationships between the diversity of gall-inducing flies and their host plants meet several fundamental predictions from island biogeographic theory. First, plant-taxon genetic distinctiveness, an integrator for long-term evolutionary history of plant lineages, is a significant predictor of variance in the diversity of gall-inducing flies among host-plant taxa. Second, range size and structural complexity also explain significant proportions of the variance in diversity of gall-inducing flies among different host-plant taxa. Third, as with other island systems, plant-lineage age does not predict species diversity. Island biogeographic theory, applied to habitats defined by genetic distance, provides a novel, comprehensive framework for analysing and explaining the diversity of plant-feeding insects and other host-specific taxa. PMID:22553094

  14. Plant-Dependent Genotypic and Phenotypic Diversity of Antagonistic Rhizobacteria Isolated from Different Verticillium Host Plants

    PubMed Central

    Berg, Gabriele; Roskot, Nicolle; Steidle, Anette; Eberl, Leo; Zock, Angela; Smalla, Kornelia

    2002-01-01

    To study the effect of plant species on the abundance and diversity of bacterial antagonists, the abundance, the phenotypic diversity, and the genotypic diversity of rhizobacteria isolated from potato, oilseed rape, and strawberry and from bulk soil which showed antagonistic activity towards the soilborne pathogen Verticillium dahliae Kleb. were analyzed. Rhizosphere and soil samples were taken five times over two growing seasons in 1998 and 1999 from a randomized field trial. Bacterial isolates were obtained after plating on R2A (Difco, Detroit, Mich.) or enrichment in microtiter plates containing high-molecular-weight substrates followed by plating on R2A. A total of 5,854 bacteria isolated from the rhizosphere of strawberry, potato, or oilseed rape or bulk soil from fallow were screened by dual testing for in vitro antagonism towards Verticillium. The proportion of isolates with antagonistic activity was highest for strawberry rhizosphere (9.5%), followed by oilseed rape (6.3%), potato (3.7%), and soil (3.3%). The 331 Verticillium antagonists were identified by their fatty acid methyl ester profiles. They were characterized by testing their in vitro antagonism against other pathogenic fungi; their glucanolytic, chitinolytic, and proteolytic activities; and their BOX-PCR fingerprints. The abundance and composition of Verticillium antagonists was plant species dependent. A rather high proportion of antagonists from the strawberry rhizosphere was identified as Pseudomonas putida B (69%), while antagonists belonging to the Enterobacteriaceae (Serratia spp., Pantoea agglomerans) were mainly isolated from the rhizosphere of oilseed rape. For P. putida A and B plant-specific genotypes were observed, suggesting that these bacteria were specifically enriched in each rhizosphere. PMID:12089011

  15. Host-plant genotypic diversity and community genetic interactions mediate aphid spatial distribution

    PubMed Central

    Zytynska, Sharon E; Frantz, Laurent; Hurst, Ben; Johnson, Andrew; Preziosi, Richard F; Rowntree, Jennifer K

    2014-01-01

    Genetic variation in plants can influence the community structure of associated species, through both direct and indirect interactions. Herbivorous insects are known to feed on a restricted range of plants, and herbivore preference and performance can vary among host plants within a species due to genetically based traits of the plant (e.g., defensive compounds). In a natural system, we expect to find genetic variation within both plant and herbivore communities and we expect this variation to influence species interactions. Using a three-species plant-aphid model system, we investigated the effect of genetic diversity on genetic interactions among the community members. Our system involved a host plant (Hordeum vulgare) that was shared by an aphid (Sitobion avenae) and a hemi-parasitic plant (Rhinanthus minor). We showed that aphids cluster more tightly in a genetically diverse host-plant community than in a genetic monoculture, with host-plant genetic diversity explaining up to 24% of the variation in aphid distribution. This is driven by differing preferences of the aphids to the different plant genotypes and their resulting performance on these plants. Within the two host-plant diversity levels, aphid spatial distribution was influenced by an interaction among the aphid's own genotype, the genotype of a competing aphid, the origin of the parasitic plant population, and the host-plant genotype. Thus, the overall outcome involves both direct (i.e., host plant to aphid) and indirect (i.e., parasitic plant to aphid) interactions across all these species. These results show that a complex genetic environment influences the distribution of herbivores among host plants. Thus, in genetically diverse systems, interspecific genetic interactions between the host plant and herbivore can influence the population dynamics of the system and could also structure local communities. We suggest that direct and indirect genotypic interactions among species can influence community structure and processes. PMID:24558568

  16. Environmental Conditions Influence the Plant Functional Diversity Effect on Potential Denitrification

    PubMed Central

    Sutton-Grier, Ariana E.; Wright, Justin P.; McGill, Bonnie M.; Richardson, Curtis

    2011-01-01

    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. PMID:21311768

  17. Differential effects of plant diversity on functional trait variation of grass species

    PubMed Central

    Gubsch, Marlén; Buchmann, Nina; Schmid, Bernhard; Schulze, Ernst-Detlef; Lipowsky, Annett; Roscher, Christiane

    2011-01-01

    Background and Aims Functional trait differences and trait adjustment in response to influences of the biotic environment could reflect niche partitioning among species. In this study, we tested how variation in above-ground plant traits, chosen as indicators for light and nitrogen acquisition and use, differs among taxonomically closely related species (Poaceae) to assess their potential for niche segregation at increasing plant diversity. Methods Traits of 12 grass species were measured in experimental grasslands (Jena Experiment) of varying species richness (from 1 to 60) and presence of particular functional groups (grasses, legumes, tall herbs and small herbs). Key Results Grass species increased shoot and leaf length, investment into supporting tissue (stem mass fraction) and specific leaf area as well as reduced foliar δ13C values with increasing species richness, indicating higher efforts for light acquisition. These species-richness effects could in part be explained by a higher probability of legume presence in more diverse communities. Leaf nitrogen concentrations increased and biomas s : N ratios in shoots decreased when grasses grew with legumes, indicating an improved nitrogen nutrition. Foliar δ15N values of grasses decreased when growing with legumes suggesting the use of depleted legume-derived N, while decreasing δ15N values with increasing species richness indicated a shift in the uptake of different N sources. However, efforts to optimize light and nitrogen acquisition by plastic adjustment of traits in response to species richness and legume presence, varied significantly among grass species. It was possible to show further that trait adjustment of grass species increased niche segregation in more diverse plant communities but that complementarity through niche separation may differ between light and nutrient acquisition. Conclusions The results suggest that even among closely related species such as grasses different strategies are used to cope with neighbours. This lack in redundancy in turn may facilitate complementary resource use and coexistence. PMID:21068024

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

    PubMed

    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. PMID:18975009

  19. Ground layer plant species turnover and beta diversity in southern-European old-growth forests.

    PubMed

    Sabatini, Francesco Maria; Burrascano, Sabina; Tuomisto, Hanna; Blasi, Carlo

    2014-01-01

    Different assembly processes may simultaneously affect local-scale variation of species composition in temperate old-growth forests. Ground layer species diversity reflects chance colonization and persistence of low-dispersal species, as well as fine-scale environmental heterogeneity. The latter depends on both purely abiotic factors, such as soil properties and topography, and factors primarily determined by overstorey structure, such as light availability. Understanding the degree to which plant diversity in old-growth forests is associated with structural heterogeneity and/or to dispersal limitation will help assessing the effectiveness of silvicultural practices that recreate old-growth patterns and structures for the conservation or restoration of plant diversity. We used a nested sampling design to assess fine-scale species turnover, i.e. the proportion of species composition that changes among sampling units, across 11 beech-dominated old-growth forests in Southern Europe. For each stand, we also measured a wide range of environmental and structural variables that might explain ground layer species turnover. Our aim was to quantify the relative importance of dispersal limitation in comparison to that of stand structural heterogeneity while controlling for other sources of environmental heterogeneity. For this purpose, we used multiple regression on distance matrices at the within-stand extent, and mixed effect models at the extent of the whole dataset. Species turnover was best predicted by structural and environmental heterogeneity, especially by differences in light availability and in topsoil nutrient concentration and texture. Spatial distances were significant only in four out of eleven stands with a relatively low explanatory power. This suggests that structural heterogeneity is a more important driver of local-scale ground layer species turnover than dispersal limitation in southern European old-growth beech forests. PMID:24748155

  20. Ground Layer Plant Species Turnover and Beta Diversity in Southern-European Old-Growth Forests

    PubMed Central

    Sabatini, Francesco Maria; Burrascano, Sabina; Tuomisto, Hanna; Blasi, Carlo

    2014-01-01

    Different assembly processes may simultaneously affect local-scale variation of species composition in temperate old-growth forests. Ground layer species diversity reflects chance colonization and persistence of low-dispersal species, as well as fine-scale environmental heterogeneity. The latter depends on both purely abiotic factors, such as soil properties and topography, and factors primarily determined by overstorey structure, such as light availability. Understanding the degree to which plant diversity in old-growth forests is associated with structural heterogeneity and/or to dispersal limitation will help assessing the effectiveness of silvicultural practices that recreate old-growth patterns and structures for the conservation or restoration of plant diversity. We used a nested sampling design to assess fine-scale species turnover, i.e. the proportion of species composition that changes among sampling units, across 11 beech-dominated old-growth forests in Southern Europe. For each stand, we also measured a wide range of environmental and structural variables that might explain ground layer species turnover. Our aim was to quantify the relative importance of dispersal limitation in comparison to that of stand structural heterogeneity while controlling for other sources of environmental heterogeneity. For this purpose, we used multiple regression on distance matrices at the within-stand extent, and mixed effect models at the extent of the whole dataset. Species turnover was best predicted by structural and environmental heterogeneity, especially by differences in light availability and in topsoil nutrient concentration and texture. Spatial distances were significant only in four out of eleven stands with a relatively low explanatory power. This suggests that structural heterogeneity is a more important driver of local-scale ground layer species turnover than dispersal limitation in southern European old-growth beech forests. PMID:24748155

  1. Assessing Diversity among Latinos: Results from the NLAAS

    PubMed Central

    Guarnaccia, Peter J.; Pincay, Igda Martinez; Alegria, Margarita; Shrout, Patrick; Lewis-Fernandez, Roberto; Canino, Glorisa

    2009-01-01

    This paper provides a profile of a range of important variables for assessing diversity among different Latino groups from the National Latino and Asian American Study (NLAAS). The NLAAS is a nationally representative study of the mental health needs and mental health services use of the Latino population of the United States. The NLAAS employs a stratified area probability sampling design. There are 2,554 respondents in the Latino portion of the NLAAS. The paper demonstrates through a detailed presentation of a wide range of variables the diverse experiences of Latino groups in their encounters with U.S. culture. Language use and migration experiences show considerable variability both within and across Latino groups and are promising areas for analysis of their mental health consequences. PMID:19672330

  2. Disparate effects of plant genotypic diversity on foliage and litter arthropod communities

    SciTech Connect

    Crutsinger, Greg; Reynolds, Nicholas; Classen, Aimee T; Sanders, Dr. Nathan James

    2008-01-01

    Intraspecific diversity within plant species is increasingly recognized as an important influence on the structure of associated arthropod communities, though whether there are congruent responses of above- and belowground communities to intraspecific diversity remains unclear. In this study, we compare the effects of host-plant genotype and genotypic diversity of the perennial plant, Solidago altissima, on the arthropod community associated with living plant tissue (foliage-based community) and microarthropods associated with leaf litter (litter-based community). We found that variation among host-plant genotypes had strong effects on the diversity and composition of foliage-based arthropods, but only weak influence on litter-based microarthropods. Furthermore, host-plant genotypic diversity was positively related to the abundance and diversity of foliage-based arthropods, including herbivore and predator trophic levels. In contrast, there were minimal effects of genotypic diversity in litter on microarthropods. Our study illustrates that incorporating both above- and belowground perspective into community genetics studies leads to very different conclusions about the importance of intraspecific diversity, than when considering aboveground responses in isolation.

  3. Assessment of bacterial diversity during composting of agricultural byproducts

    PubMed Central

    2013-01-01

    Background Composting is microbial decomposition of biodegradable materials and it is governed by physicochemical, physiological and microbiological factors. The importance of microbial communities (bacteria, actinomycetes and fungi) during composting is well established. However, the microbial diversity during composting may vary with the variety of composting materials and nutrient supplements. Therefore, it is necessary to study the diversity of microorganisms during composting of different agricultural byproducts like wheat bran, rice bran, rice husk, along with grass clippings and bulking agents. Here it has been attempted to assess the diversity of culturable bacteria during composting of agricultural byproducts. Results The culturable bacterial diversity was assessed during the process by isolating the most prominent bacteria. Bacterial population was found to be maximum during the mesophilic phase, but decreased during the thermophilic phase and declined further in the cooling and maturation phase of composting. The bacterial population ranged from 105 to 109 cfu g-1 compost. The predominant bacteria were characterized biochemically, followed by 16S rRNA gene sequencing. The isolated strains, both Gram-positive and Gram-negative groups belonged to the order Burkholderiales, Enterobacteriales, Actinobacteriales and Bacillales, which includes genera e.g. Staphylococcus, Serratia, Klebsiella, Enterobacter, Terribacillus, Lysinibacillus Kocuria, Microbacterium, Acidovorax and Comamonas. Genera like Kocuria, Microbacterium, Acidovorax, Comamonas and some new species of Bacillus were also identified for the first time from the compost made from agricultural byproducts. Conclusion The use of appropriate nitrogen amendments and bulking agents in composting resulted in good quality compost. The culture based strategy enabled us to isolate some novel bacterial isolates like Kocuria, Microbacterium, Acidovorax and Comamonas first time from agro-byproducts compost. These bacteria can be used as potential compost inoculants for accelerating composting process. PMID:23651653

  4. Global Analysis of Proline-Rich Tandem Repeat Proteins Reveals Broad Phylogenetic Diversity in Plant Secretomes

    PubMed Central

    Newman, Aaron M.; Cooper, James B.

    2011-01-01

    Cell walls, constructed by precisely choreographed changes in the plant secretome, play critical roles in plant cell physiology and development. Along with structural polysaccharides, secreted proline-rich Tandem Repeat Proteins (TRPs) are important for cell wall function, yet the evolutionary diversity of these structural TRPs remains virtually unexplored. Using a systems-level computational approach to analyze taxonomically diverse plant sequence data, we identified 31 distinct Pro-rich TRP classes targeted for secretion. This analysis expands upon the known phylogenetic diversity of extensins, the most widely studied class of wall structural proteins, and demonstrates that extensins evolved before plant vascularization. Our results also show that most Pro-rich TRP classes have unexpectedly restricted evolutionary distributions, revealing considerable differences in plant secretome signatures that define unexplored diversity. PMID:21829715

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

    PubMed

    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 far-reaching significance for sustainable development of Chinese economy and society. PMID:22059249

  6. Habitats as Complex Odour Environments: How Does Plant Diversity Affect Herbivore and Parasitoid Orientation?

    PubMed Central

    Wäschke, Nicole; Hardge, Kristin; Hancock, Christine; Hilker, Monika; Obermaier, Elisabeth; Meiners, Torsten

    2014-01-01

    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. PMID:24416354

  7. Diversity and phylogeny of plant growth-promoting bacilli from moderately acidic soil.

    PubMed

    Yadav, Subhash; Kaushik, Rajeev; Saxena, Anil K; Arora, Dilip K

    2011-02-01

    The molecular diversity of aerobic endospore-forming bacteria, typically Bacillus and its derived genera, has been investigated in various environments. However, there have been few investigations concerning Bacillus in acidic soils. In this study, the genotypic diversity and phylogenetic relationships among plant growth-promoting (PGP) bacilli isolated from the rice rhizosphere growing in acidic soils of Kerala (pH varying from 6.3 to 6.8) were investigated. For assessing their biocontrol potential and PGP attributes, 115 isolates were randomly selected and 49 isolates that were positive for multiple traits were selected. Metabolic characterization of representative strains, using the Biolog GP2 (Gram Positive) MicroPlate(TM) , revealed a large versatility with respect to carbohydrate utilization. Amplified ribosomal DNA restriction analysis revealed 13 clusters at 65% similarity level, which consisted of 1-21 strains. 16S rDNA partial sequencing assigned all the isolates, except for one, to the Bacillus genus, with close relatedness to Bacillus humi, B. megaterium, B. drentensis, B. pocheonensis, B. aestuarii, B. arbutinivorans, B. niacini, and Brevibacterium casei. The Bacillus species with different metabolic capabilities, PGP abilities, and genetic diversity found in this study are likely to have ecological relevance. PMID:21077114

  8. Relationships between plant diversity and grasshopper diversity and abundance in the Little Missouri National Grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A continuing challenge in Orthoptera ecology is to understand what determines grasshopper species diversity at a given site. In this study, the objective was to determine if variation in grasshopper abundance and diversity between 23 sites in western North Dakota (USA) could be explained by variatio...

  9. Psychometric Evaluation of Lexical Diversity Indices: Assessing Length Effects

    PubMed Central

    Wright, Heather Harris; Green, Samuel B.

    2015-01-01

    Purpose Several novel techniques have been developed recently to assess the breadth of a speaker's vocabulary exhibited in a language sample. The specific aim of this study was to increase our understanding of the validity of the scores generated by different lexical diversity (LD) estimation techniques. Four techniques were explored: D, Maas, measure of textual lexical diversity, and moving-average type–token ratio. Method Four LD indices were estimated for language samples on 4 discourse tasks (procedures, eventcasts, story retell, and recounts) from 442 adults who are neurologically intact. The resulting data were analyzed using structural equation modeling. Results The scores for measure of textual lexical diversity and moving-average type–token ratio were stronger indicators of the LD of the language samples. The results for the other 2 techniques were consistent with the presence of method factors representing construct-irrelevant sources. Conclusion These findings offer a deeper understanding of the relative validity of the 4 estimation techniques and should assist clinicians and researchers in the selection of LD measures of language samples that minimize construct-irrelevant sources. PMID:25766139

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

    PubMed Central

    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. PMID:26197473

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

    PubMed

    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. PMID:26197473

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

    PubMed

    Moreira, Xoaquín; Abdala-Roberts, Luis; Parra-Tabla, Víctor; Mooney, Kailen A

    2014-01-01

    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 diversity effects on plant chemical defenses. PMID:25141305

  13. Positive Effects of Plant Genotypic and Species Diversity on Anti-Herbivore Defenses in a Tropical Tree Species

    PubMed Central

    Moreira, Xoaquín; Abdala-Roberts, Luis; Parra-Tabla, Víctor; Mooney, Kailen A.

    2014-01-01

    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 diversity effects on plant chemical defenses. PMID:25141305

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

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

    2014-01-01

    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. PMID:25147872

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

    USGS Publications Warehouse

    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.

  16. Disentangling direct and indirect effects of experimental grassland management and plant functional-group manipulation on plant and leafhopper diversity

    PubMed Central

    2014-01-01

    Background Plant biodiversity can affect trophic interactions in many ways, including direct bottom-up effects on insects, but is negatively affected by agricultural intensification. Grassland intensification promotes plant productivity, resulting in changes in plant community composition, and impacts on higher trophic levels. Here, we use a novel grassland management experiment combining manipulations of cutting and fertilization with experimental changes in plant functional group composition (independent of management effects) to disentangle the direct and indirect effects of agricultural management on insect herbivore diversity and abundance. We used leafhoppers as model organisms as they are a key insect taxon in grasslands and react rapidly to management changes. Leafhoppers were sampled between May and September 2010 using standardized sweep netting and pan traps. Results Plant diversity, functional group composition and management regime in grasslands affected leafhopper species richness and abundance. Higher cutting frequencies directly led to decreasing leafhopper species richness, presumably due to the higher disturbance frequency and the reduction in food-resource heterogeneity. In contrast, fertilizer application had only a small indirect negative effect via enhanced aboveground plant biomass, reduced plant diversity and changes in functional group composition. The manipulated increase in grass cover had contrasting direct and indirect effects on leafhopper species richness: grass cover directly increased leafhopper species richness, but negatively affected plant diversity, which in turn was positively related to leafhopper species richness. In conclusion, insect diversity is driven in complex direct and indirect ways by grassland management, including changes in functional group composition. Conclusions The availability of preferred food sources and the frequency of disturbance are important direct and indirect drivers of leafhopper species richness, interacting in complex ways with plant diversity and food resource heterogeneity. PMID:24438134

  17. Measuring the fate of plant diversity: towards a foundation for future monitoring and opportunities for urgent action

    PubMed Central

    Nic Lughadha, E; Baillie, J; Barthlott, W; Brummitt, N.A; Cheek, M.R; Farjon, A; Govaerts, R; Hardwick, K.A; Hilton-Taylor, C; Meagher, T.R; Moat, J; Mutke, J; Paton, A.J; Pleasants, L.J; Savolainen, V; Schatz, G.E; Smith, P; Turner, I; Wyse-Jackson, P; Crane, P.R

    2005-01-01

    Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200 000 to 422 000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10 000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the world's major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates. PMID:15814350

  18. Protein change in plant evolution: tracing one thread connecting molecular and phenotypic diversity

    PubMed Central

    Bartlett, Madelaine E.; Whipple, Clinton J.

    2013-01-01

    Proteins change over the course of evolutionary time. New protein-coding genes and gene families emerge and diversify, ultimately affecting an organism’s phenotype and interactions with its environment. Here we survey the range of structural protein change observed in plants and review the role these changes have had in the evolution of plant form and function. Verified examples tying evolutionary change in protein structure to phenotypic change remain scarce. We will review the existing examples, as well as draw from investigations into domestication, and quantitative trait locus (QTL) cloning studies searching for the molecular underpinnings of natural variation. The evolutionary significance of many cloned QTL has not been assessed, but all the examples identified so far have begun to reveal the extent of protein structural diversity tolerated in natural systems. This molecular (and phenotypic) diversity could come to represent part of natural selection’s source material in the adaptive evolution of novel traits. Protein structure and function can change in many distinct ways, but the changes we identified in studies of natural diversity and protein evolution were predicted to fall primarily into one of six categories: altered active and binding sites; altered protein–protein interactions; altered domain content; altered activity as an activator or repressor; altered protein stability; and hypomorphic and hypermorphic alleles. There was also variability in the evolutionary scale at which particular changes were observed. Some changes were detected at both micro- and macroevolutionary timescales, while others were observed primarily at deep or shallow phylogenetic levels. This variation might be used to determine the trajectory of future investigations in structural molecular evolution. PMID:24124420

  19. High plant diversity in Oregon tidal wetlands and multiple threats to its persistence

    EPA Science Inventory

    Tidal wetlands in the Pacific Northwest occur in coastal estuaries differing widely in size, relative freshwater inputs, and degree of watershed development. To better understand patterns of plant diversity in tidal wetlands across the region and potential climate change effects ...

  20. Decline in exotic tree density facilitates increased plant diversity: the experience from Melaleuca quinquenervia invaded wetlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Australian tree Melaleuca quinquenervia (melaleuca) formed dense monocultural forests several decades after invading Florida and the Caribbean islands. These dominant forests have displaced native vegetation in sensitive wetland systems. We hypothesized that native plant diversity would increa...

  1. Evaluation of genetic and functional diversity of Stenotrophomonas isolates from diverse effluent treatment plants.

    PubMed

    Verma, Vinita; Raju, Sajan C; Kapley, Atya; Kalia, Vipin Chandra; Daginawala, Hatim F; Purohit, Hemant J

    2010-10-01

    In this study, the samples were collected from nine ETPs and soil contaminated with petroleum products. The genetic diversity of 30 Stenotrophomonas isolates was demonstrated by phylogenetic analysis of their 16S rRNA gene nucleotide sequences, and randomly amplified polymorphic DNA (RAPD) analysis supplemented with in silico signature and restriction enzyme (REs--AluI, BfaI, DpnII, HaeIII, RsaI and Tru9I) digestion analyses. Genetic diversity based on nucleotide sequence data revealed distinct clusters. Functional diversity was analysed on the basis of the abilities of these isolates to degrade phenol, p-cresol, catechol, 4-methylcatechol and hydroquinone. Based on the environmental, genetic and functional diversities, a consortium of mixed defined microbes has been proposed for bioremediation programs. PMID:20554196

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

    PubMed Central

    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. PMID:26379656

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

    PubMed

    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. PMID:26379656

  4. Genomic Diversity of Biocontrol Strains of Pseudomonas spp. Isolated from Aerial or Root Surfaces of Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The striking ecological, metabolic, and biochemical diversity of Pseudomonas has intrigued microbiologists for many decades. To explore the genomic diversity of biocontrol strains of Pseudomonas spp., we derived high quality draft sequences of seven strains known to suppress plant disease. The str...

  5. Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Doethideomycetes Fungi

    SciTech Connect

    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.

  6. Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Dothideomycetes

    SciTech Connect

    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.

  7. Pathways of nutrient loading and impacts on plant diversity in a New York peatland

    USGS Publications Warehouse

    Drexler, J.Z.; Bedford, B.L.

    2002-01-01

    Nutrient loading is a subtle, yet serious threat to the preservation of high diversity wetlands such as peatlands. Pathways of nutrient loading and impacts on plant diversity in a small peatland in New York State, USA were determined by collecting and analyzing a suite of hydrogeological, hydro-chemical, soil, and vegetation data. Piezometer clusters within an intensive network constituted hydro-chemical sampling points and focal points for randomly selected vegetation quadrats and soil-coring locations. Hydrogeological data and nutrient analyses showed that P and K loading occurred chiefly by means of overland flow from an adjacent farm field, whereas N loading occurred predominantly through ground-water flow from the farm field. Redundancy analysis and polynomial regression showed that nutrients, particularly total P in peat, total K in peat, extractable NH4-N, and NO3-N flux in ground water, were strongly negatively correlated with plant diversity measures at the site. No other environmental variables except vegetation measures associated with eutrophication demonstrated such a strong relationship with plant diversity. Nitrate loading over 4 mg m -2 day-1 was associated with low plant diversity, and Ca fluxes between 80 and 130 mg m-2 day-1 were associated with high plant diversity. Areas in the site with particularly low vascular plant and bryophyte species richness and Shannon-Wiener diversity (H') occurred adjacent to the farm field and near a hillside spring. High H' and species richness of vascular plants and bryophytes occurred in areas that were further removed from agriculture, contained no highly dominant vegetation, and were situated directly along the ground-water flow paths of springs. These areas were characterized by relatively constant water levels and consistent, yet moderate fluxes of base cations and nutrients. Overall, this study demonstrates that knowledge of site hydrogeology is crucial for determining potential pathways of nutrient loading and for developing relationships between nutrient inflows and wetland plant diversity. ?? 2002, The Society of Wetland Scientists.

  8. Plant Wide Assessment for SIFCO Industries, Inc.

    SciTech Connect

    Kelly Kissock, Arvind Thekdi et. al.

    2005-07-06

    Sifco Industries carreid out a plant wide energy assessment under a collaborative program with the U.S. Department of Energy during October 2004 to September 2005. During the year, personnel from EIS, E3M, DPS, BuyCastings.Com, and Sifco plant facilities and maintenance personnel, as a team collected energy use, construction, process, equipment and operational information about the plant. Based on this information, the team identified 13 energy savings opportunities. Near term savings opportunities have a total potential savings of about $1,329,000 per year and a combined simple payback of about 11 months. Implementation of these recommendations would reduce CO2 emissions by about 16,000,000 pounds per year, which would reduce overall plant CO2 emissions by about 45%. These totals do not include another $830,000 per year in potential savings with an estimated 9-month payback, from converting the forging hammers from steam to compressed air.

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

    PubMed

    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. PMID:26389742

  10. Nuclear power plant security assessment technical manual.

    SciTech Connect

    O'Connor, Sharon L.; Whitehead, Donnie Wayne; Potter, Claude S., III

    2007-09-01

    This report (Nuclear Power Plant Security Assessment Technical Manual) is a revision to NUREG/CR-1345 (Nuclear Power Plant Design Concepts for Sabotage Protection) that was published in January 1981. It provides conceptual and specific technical guidance for U.S. Nuclear Regulatory Commission nuclear power plant design certification and combined operating license applicants as they: (1) develop the layout of a facility (i.e., how buildings are arranged on the site property and how they are arranged internally) to enhance protection against sabotage and facilitate the use of physical security features; (2) design the physical protection system to be used at the facility; and (3) analyze the effectiveness of the PPS against the design basis threat. It should be used as a technical manual in conjunction with the 'Nuclear Power Plant Security Assessment Format and Content Guide'. The opportunity to optimize physical protection in the design of a nuclear power plant is obtained when an applicant utilizes both documents when performing a security assessment. This document provides a set of best practices that incorporates knowledge gained from more than 30 years of physical protection system design and evaluation activities at Sandia National Laboratories and insights derived from U.S. Nuclear Regulatory Commission technical staff into a manual that describes a development and analysis process of physical protection systems suitable for future nuclear power plants. In addition, selected security system technologies that may be used in a physical protection system are discussed. The scope of this document is limited to the identification of a set of best practices associated with the design and evaluation of physical security at future nuclear power plants in general. As such, it does not provide specific recommendations for the design and evaluation of physical security for any specific reactor design. These best practices should be applicable to the design and evaluation of physical security for all future plants. Note that the original NUREG/CR-1345 remains valid for many light water reactor designs. While the focus of this document is on new plants, existing nuclear power plants and nuclear material facilities may be able to apply these best practices and security system technologies when upgrading or modifying their physical protection systems.

  11. ?-Diversity of functional groups of woody plants in a tropical dry forest in Yucatan.

    PubMed

    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 (?-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 ?-diversity. In this study, we first explored how ?- and ?-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 ?-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 ?-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. ?-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 ?-diversity across functional groups, but showed a low influence on ?-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 ?- and ?-diversity patterns and correlates that are not apparent when focusing on overall woody plant diversity, and that have important implications for ecological theory and biodiversity conservation. PMID:24040014

  12. ?-Diversity of Functional Groups of Woody Plants in a Tropical Dry Forest in Yucatan

    PubMed Central

    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 (?-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 ?-diversity. In this study, we first explored how ?- and ?-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 ?-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 ?-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. ?-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 ?-diversity across functional groups, but showed a low influence on ?-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 ?- and ?-diversity patterns and correlates that are not apparent when focusing on overall woody plant diversity, and that have important implications for ecological theory and biodiversity conservation. PMID:24040014

  13. On the factors that promote the diversity of herbivorous insects and plants in tropical forests.

    PubMed

    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. PMID:25902509

  14. On the factors that promote the diversity of herbivorous insects and plants in tropical forests

    PubMed Central

    Becerra, Judith X.

    2015-01-01

    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. PMID:25902509

  15. Seasonal changes in plant diversity and abundance in Northeastern pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The number and identity of plant species varies by season and location. We sampled pastures on five grazing farms (four dairy, one beef): two in New York, two in Pennsylvania, and one in Maryland. Pasture plant composition was measured on five to seven pastures in the spring (April-May), summer (Jul...

  16. Interactive effects of plant species diversity and elevated CO2 on soil biota and nutrient cycling.

    PubMed

    Niklaus, P A; Alphei, J; Kampichler, C; Kandeler, E; Körner, C; Tscherko, D; Wohlfender, M

    2007-12-01

    Terrestrial ecosystems consist of mutually dependent producer and decomposer subsystems, but not much is known on how their interactions are modified by plant diversity and elevated atmospheric CO2 concentrations. Factorially manipulating grassland plant species diversity and atmospheric CO2 concentrations for five years, we tested whether high diversity or elevated CO2 sustain larger or more active soil communities, affect soil aggregation, water dynamics, or nutrient cycling, and whether plant diversity and elevated CO2 interact. Nitrogen (N) and phosphorus (P) pools, symbiotic N2 fixation, plant litter quality, soil moisture, soil physical structure, soil nematode, collembola and acari communities, soil microbial biomass and microflora community structure (phospholipid fatty acid [PLFA] profiles), soil enzyme activities, and rates of C fluxes to soils were measured. No increases in soil C fluxes or the biomass, number, or activity of soil organisms were detected at high plant diversity; soil H2O and aggregation remained unaltered. Elevated CO2 affected the ecosystem primarily by improving plant and soil water status by reducing leaf conductance, whereas changes in C cycling appeared to be of subordinate importance. Slowed-down soil drying cycles resulted in lower soil aggregation under elevated CO2. Collembola benefited from extra soil moisture under elevated CO2, whereas other faunal groups did not respond. Diversity effects and interactions with elevated CO2 may have been absent because soil responses were mainly driven by community-level processes such as rates of organic C input and water use; these drivers were not changed by plant diversity manipulations, possibly because our species diversity gradient did not extend below five species and because functional type composition remained unaltered. Our findings demonstrate that global change can affect soil aggregation, and we advocate that soil aggregation should be considered as a dynamic property that may respond to environmental changes and feed back on other ecosystem functions. PMID:18229849

  17. Host-plants shape insect diversity: phylogeny, origin, and species diversity of native Hawaiian leafhoppers (Cicadellidae: Nesophrosyne).

    PubMed

    Bennett, Gordon M; O'Grady, Patrick M

    2012-11-01

    Herbivorous insects and the plants on which they specialize, represent the most abundant terrestrial life on earth, yet their inter-specific interactions in promoting species diversification remains unclear. This study utilizes the discreet geologic attributes of Hawai'i and one of the most diverse endemic herbivore radiations, the leafhoppers (Hemiptera: Cicadellidae: Nesophrosyne), as a model system to understand the role of host-plant use in insect diversification. A comprehensive phylogeny is reconstructed to examine the origins, species diversification, and host-plant use of the native Hawaiian leafhoppers. Results support a monophyletic Nesophrosyne, originating from the Western Pacific basin, with a sister-group relationship to the genus Orosius. Nesophrosyne is characterized by high levels of endemicity according to individual islands, volcanoes, and geologic features. Clades demonstrate extensive morphologically cryptic diversity among allopatric species, utilizing widespread host-plant lineages. Nesophrosyne species are host-plant specific, demonstrating four dominant patterns of specialization that shape species diversification: (1) diversification through host switching; (2) specialization on widespread hosts with allopatric speciation; (3) repeated, independent shifts to the same hosts; and, (4) absence or low abundance on some host. Finally, evidence suggests competing herbivore radiations limit ecological opportunity for diversifying insect herbivores. Results provide evolutionary insights into the mechanisms that drive and shape this biodiversity. PMID:22884527

  18. Plant Diversity and Multifunctional Management of Grassland Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing for multiple ecosystem functions and services requires greater ecosystem diversity and complexity. Complex ecosystems, such as forage and grazing lands, may provide multiple benefits and require multiple species. In this paper, I provide a brief perspective from our research conducted in th...

  19. [Agrobacterium rubi strains from blueberry plants are highly diverse].

    PubMed

    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. PMID:25444133

  20. Exploiting a wheat EST database to assess genetic diversity

    PubMed Central

    2010-01-01

    Expressed sequence tag (EST) markers have been used to assess variety and genetic diversity in wheat (Triticum aestivum). In this study, 1549 ESTs from wheat infested with yellow rust were used to examine the genetic diversity of six susceptible and resistant wheat cultivars. The aim of using these cultivars was to improve the competitiveness of public wheat breeding programs through the intensive use of modern, particularly marker-assisted, selection technologies. The F2 individuals derived from cultivar crosses were screened for resistance to yellow rust at the seedling stage in greenhouses and adult stage in the field to identify DNA markers genetically linked to resistance. Five hundred and sixty ESTs were assembled into 136 contigs and 989 singletons. BlastX search results showed that 39 (29%) contigs and 96 (10%) singletons were homologous to wheat genes. The database-matched contigs and singletons were assigned to eight functional groups related to protein synthesis, photosynthesis, metabolism and energy, stress proteins, transporter proteins, protein breakdown and recycling, cell growth and division and reactive oxygen scavengers. PCR analyses with primers based on the contigs and singletons showed that the most polymorphic functional categories were photosynthesis (contigs) and metabolism and energy (singletons). EST analysis revealed considerable genetic variability among the Turkish wheat cultivars resistant and susceptible to yellow rust disease and allowed calculation of the mean genetic distance between cultivars, with the greatest similarity (0.725) being between Harmankaya99 and Sönmez2001, and the lowest (0.622) between Aytin98 and Izgi01. PMID:21637582

  1. Plant growth promotion potential is equally represented in diverse grapevine root-associated bacterial communities from different biopedoclimatic environments.

    PubMed

    Marasco, Ramona; Rolli, Eleonora; Fusi, Marco; Cherif, Ameur; Abou-Hadid, Ayman; El-Bahairy, Usama; Borin, Sara; Sorlini, Claudia; Daffonchio, Daniele

    2013-01-01

    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. PMID:23878810

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

    PubMed Central

    Fusi, Marco; Cherif, Ameur; Abou-Hadid, Ayman; El-Bahairy, Usama; Sorlini, Claudia; Daffonchio, Daniele

    2013-01-01

    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. PMID:23878810

  3. Photosynthetic diversity meets biodiversity: the C4 plant example.

    PubMed

    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. PMID:25264020

  4. Assessment of phytoplankton diversity as an indicator of water quality

    SciTech Connect

    Yergeau, S.E.; Lang, A.; Teeters, R.

    1997-08-01

    For the measurement of water quality in freshwater systems, there are established indices using macroinvertebrate larvae. There is no such comparable measure for marine and estuarine environments. A phytoplankton diversity index (PDI), whose basic form was conceived by Dr. Ruth Gyure of Save the Sound, Inc., is being investigated as a possible candidate to rectify this situation. Phytoplankton were chosen as the indicators of water quality since algae have short generation times and respond quickly to changing water quality conditions. The methodologies involved in this initial assessment of the PDI are incorporated into the Adopt-a-Harbor water quality monitoring program and its associated laboratory. The virtues of the procedures are that they are simple and quick to use, suitable for trained volunteers to carry out, easily reproducible, and amenable to quality assurance checks.

  5. Potential benefits of plant diversity on vegetated roofs: a literature review.

    PubMed

    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. PMID:22575204

  6. The impact of genomic approaches on our understanding of diversity and taxonomy of plant pathogenic bacteria.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our understanding of the diversity of bacterial plant pathogens has changed dramatically over the past 100 years. Initially it was thought that each newly described disease was caused by a distinct plant pathogen species. Later, similarities in the physiology of these pathogens as well as inadequate...

  7. Plant Species Diversity and Distribution in Pastures of the Northeastern USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazed pastures in the northeastern United contain far more than planted forage species. These species may contribute to forage production, but they may also detract from forage production or palatability. As the first step toward identifying the role of plant diversity in forage systems, we collect...

  8. Diversity dynamics of silurian-early carboniferous land plants in South china.

    PubMed

    Xiong, Conghui; Wang, Deming; Wang, Qi; Benton, Michael J; Xue, Jinzhuang; Meng, Meicen; Zhao, Qi; Zhang, Jing

    2013-01-01

    New megafossil and microfossil data indicate four episodes in the diversification of Silurian-Early Carboniferous land plants of South China, a relatively continuous regional record. Plant diversity increased throughout, but the rising curve was punctuated by three major falls. There were peaks of origination in the Ludlow-Pragian, Givetian, late Famennian and Visean and peaks of extinction in the Pragian-Emsian, Givetian and early Tournaisian. Speciation and extinction rates were highest in the Lochkovian-Pragian and became progressively lower in subsequent stages. High correlation coefficients indicate that these events are associated with the availability of land habitat contingent on eustatic variations and increasing numbers of cosmopolitan genera. Meanwhile, proportions of endemic genera declined gradually. Due to less endemism and more migrations, both speciation and species extinction rates reduced. The changes of diversity and the timing of the three extinctions of land plants in South China are similar to those known already from Laurussia. However, the largest events in the Lochkovian-Pragian and subsequent smaller ones have not been seen in the global pattern of plant evolution. These land plant events do not correspond well temporally with those affecting land vertebrates or marine invertebrates. In South China, the diversity curve of land plants is generally opposite to that of marine faunas, showing a strong effect of eustatic variations. The increasing diversity of both land vertebrates and plants was punctuated above the Devonian-Carboniferous boundary, known as Romer's Gap, implying common underlying constraints on macroevolution of land animals and plants. PMID:24073276

  9. Diversity Dynamics of Silurian–Early Carboniferous Land Plants in South China

    PubMed Central

    Xiong, Conghui; Wang, Deming; Wang, Qi; Benton, Michael J.; Xue, Jinzhuang; Meng, Meicen; Zhao, Qi; Zhang, Jing

    2013-01-01

    New megafossil and microfossil data indicate four episodes in the diversification of Silurian–Early Carboniferous land plants of South China, a relatively continuous regional record. Plant diversity increased throughout, but the rising curve was punctuated by three major falls. There were peaks of origination in the Ludlow–Pragian, Givetian, late Famennian and Visean and peaks of extinction in the Pragian–Emsian, Givetian and early Tournaisian. Speciation and extinction rates were highest in the Lochkovian–Pragian and became progressively lower in subsequent stages. High correlation coefficients indicate that these events are associated with the availability of land habitat contingent on eustatic variations and increasing numbers of cosmopolitan genera. Meanwhile, proportions of endemic genera declined gradually. Due to less endemism and more migrations, both speciation and species extinction rates reduced. The changes of diversity and the timing of the three extinctions of land plants in South China are similar to those known already from Laurussia. However, the largest events in the Lochkovian–Pragian and subsequent smaller ones have not been seen in the global pattern of plant evolution. These land plant events do not correspond well temporally with those affecting land vertebrates or marine invertebrates. In South China, the diversity curve of land plants is generally opposite to that of marine faunas, showing a strong effect of eustatic variations. The increasing diversity of both land vertebrates and plants was punctuated above the Devonian–Carboniferous boundary, known as Romer's Gap, implying common underlying constraints on macroevolution of land animals and plants. PMID:24073276

  10. THE NATIONAL PLANT GERMPLASM SYSTEM'S SUNFLOWER COLLECTION: GENETIC DIVERSITY FOR DEVELOPING COUNTRIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The United States' National Plant Germplasm System's (NPGS) sunflower collection is curated at the North Central Regional Plant Introduction Station (NCRPIS) in Ames, Iowa (USA). The NPGS sunflower collection is a diverse assemblage of 3787 accessions (1624 cultivated Helianthus annuus accessions, ...

  11. Genetic diversity and domestication origin of tea plant Camellia taliensis (Theaceae) as revealed by microsatellite markers

    PubMed Central

    2014-01-01

    Background Tea is one of the most popular beverages in the world. Many species in the Thea section of the Camellia genus can be processed for drinking and have been domesticated. However, few investigations have focused on the genetic consequence of domestication and geographic origin of landraces on tea plants using credible wild and planted populations of a single species. Here, C. taliensis provides us with a unique opportunity to explore these issues. Results Fourteen nuclear microsatellite loci were employed to determine the genetic diversity and domestication origin of C. taliensis, which were represented by 587 individuals from 25 wild, planted and recently domesticated populations. C. taliensis showed a moderate high level of overall genetic diversity. The greater reduction of genetic diversity and stronger genetic drift were detected in the wild group than in the recently domesticated group, indicating the loss of genetic diversity of wild populations due to overexploitation and habitat fragmentation. Instead of the endangered wild trees, recently domesticated individuals were used to compare with the planted trees for detecting the genetic consequence of domestication. A little and non-significant reduction in genetic diversity was found during domestication. The long life cycle, selection for leaf traits and gene flow between populations will delay the emergence of bottleneck in planted trees. Both phylogenetic and assignment analyses suggested that planted trees may have been domesticated from the adjacent central forest of western Yunnan and dispersed artificially to distant places. Conclusions This study contributes to the knowledge about levels and distribution of genetic diversity of C. taliensis and provides new insights into genetic consequence of domestication and geographic origin of planted trees of this species. As an endemic tea source plant, wild, planted and recently domesticated C. taliensis trees should all be protected for their unique genetic characteristics, which are valuable for tea breeding. PMID:24405939

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human alterations to nutrient cycles and herbivore communities are dramatically altering global biodiversity. Theory predicts these changes to be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive excl...

  13. Diversity of use and local knowledge of wild edible plant resources in Nepal

    PubMed Central

    2012-01-01

    Background Wild edible plants (WEP) provide staple and supplement foods, as well as cash income to local communities, thus favouring food security. However, WEP are largely ignored in land use planning and implementation, economic development, and biodiversity conservation. Moreover, WEP-related traditional knowledge is rapidly eroding. Therefore, we designed this study to fulfill a part of the knowledge gap by providing data on diversity, traditional knowledge, economic potential, and conservation value of WEP from Nepal. Methods The information was collected through focus group discussions and key informant interviews. Percentage of general utility of the plants among the study communities was evaluated using the Chi-square (χ2) test of homogeneity. High priority species were identified after consultation with the local stakeholders followed by scoring based on defined criteria. Pairwise ranking was used to assess ethnoecological knowledge to identify the threats to WEP. Results We documented 81 species belonging to Angiosperms (74), Pteridophytes (5), and Fungi (2). Most of the species were used as fruits (44 species) followed by vegetables (36). Almost half of the species (47%) were also used for purposes other than food. From the species with market value (37% of the total), 10 were identified as high priority species. Pairwise ranking revealed that WEP are threatened mostly by habitat destruction, land-use change and over-harvesting. Some of these plants are crop wild relatives and could thus be used for crop improvement. Interestingly, our study also revealed that young people who spend most of the time in the forest as herdsmen are particularly knowledgeable of wild fruit plants. Conclusion We provide empirical evidence from a relatively large area of Nepal about diversity and status of WEP, as well as methodological insights about the proper knowledge holders to consult. Regarding the unique and important knowledge they have on WEP, young people should be included when recruiting participants to ethnobotanical studies or to any type of consultation about WEP. The habit of using wild edible plants is still alive and is a traditional culinary practice that demonstrates rich traditional knowledge of local people. WEP were found to be important for livelihood as well as showing great potential for crop improvement. Priority species should be promoted for income generation activities through sustainable collection and trade. Communities should engage in minimizing the threats to these valuable resources. PMID:22546349

  14. Mapping Viral Functional Domains for Genetic Diversity in Plants

    PubMed Central

    Pita, Justin S.

    2013-01-01

    Cucumber mosaic virus (CMV) comprises numerous isolates with various levels of in-host diversity. Subgroup-distinctive features of the Fny and LS strains provided us with a platform to genetically map the viral control elements for genetic variation in planta. We found that both RNAs 1 and 2 controlled levels of genetic diversity, and further fine mapping revealed that the control elements of mutation frequency reside within the first 596 amino acids (aa) of RNA 1. The 2a/2b overlapping region of the 2a protein also contributed to control of viral genetic variation. Furthermore, the 3? nontranslated region (NTR) of RNA 3 constituted a hot spot of polymorphism, where the majority of fixed mutations found in the population were clustered. The 2b gene of CMV, a viral suppressor of gene silencing, controls the abundance of the fixed mutants in the viral population via a host-dependent mechanism. PMID:23115283

  15. Biodiversity assessment among two Nebraska prairies: a comparison between traditional and phylogenetic diversity indices

    PubMed Central

    Aust, Shelly K.; Ahrendsen, Dakota L.

    2015-01-01

    Abstract Background Conservation of the evolutionary diversity among organisms should be included in the selection of priority regions for preservation of Earth’s biodiversity. Traditionally, biodiversity has been determined from an assessment of species richness (S), abundance, evenness, rarity, etc. of organisms but not from variation in species’ evolutionary histories. Phylogenetic diversity (PD) measures evolutionary differences between taxa in a community and is gaining acceptance as a biodiversity assessment tool. However, with the increase in the number of ways to calculate PD, end-users and decision-makers are left wondering how metrics compare and what data are needed to calculate various metrics. New information In this study, we used massively parallel sequencing to generate over 65,000 DNA characters from three cellular compartments for over 60 species in the asterid clade of flowering plants. We estimated asterid phylogenies from character datasets of varying nucleotide quantities, and then assessed the effect of varying character datasets on resulting PD metric values. We also compared multiple PD metrics with traditional diversity indices (including S) among two endangered grassland prairies in Nebraska (U.S.A.). Our results revealed that PD metrics varied based on the quantity of genes used to infer the phylogenies; therefore, when comparing PD metrics between sites, it is vital to use comparable datasets. Additionally, various PD metrics and traditional diversity indices characterize biodiversity differently and should be chosen depending on the research question. Our study provides empirical results that reveal the value of measuring PD when considering sites for conservation, and it highlights the usefulness of using PD metrics in combination with other diversity indices when studying community assembly and ecosystem functioning. Ours is just one example of the types of investigations that need to be conducted across the tree of life and across varying ecosystems in order to build a database of phylogenetic diversity assessments that lead to a pool of results upon which a guide through the plethora of PD metrics may be prepared for use by ecologists and conservation planners. PMID:26312052

  16. Effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China

    PubMed Central

    Li, Youzhi; Chen, Xinsheng; Xie, Yonghong; Li, Xu; Li, Feng; Hou, Zhiyong

    2014-01-01

    This study evaluated the effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China. Poplar plantations resulted in a higher species number and Shannon's diversity. Species compositions were different between areas with poplar and reed populations: a lower ratio of hygrophytes but a higher ratio of mesophytes, and a higher ratio of heliophytes but a lower ratio of neutrophilous or shade plants in poplar areas compared to reed areas. Poplar plantations supported a higher ratio of ligneous plants in the entire Dongting Lake area, but there was no difference in the monitored plots. Unlike reedy areas, poplar plantations had higher light availability but lower soil water content during the growing seasons. These data suggest that young poplar plantations generally increased species richness and plant diversity, but significantly changed species composition due to the reduced soil water and increased light availability. PMID:25208975

  17. Non-native plants add to the British flora without negative consequences for native diversity

    PubMed Central

    Thomas, Chris D.; Palmer, G.

    2015-01-01

    Plants are commonly listed as invasive species, presuming that they cause harm at both global and regional scales. Approximately 40% of all species listed as invasive within Britain are plants. However, invasive plants are rarely linked to the national or global extinction of native plant species. The possible explanation is that competitive exclusion takes place slowly and that invasive plants will eventually eliminate native species (the “time-to-exclusion hypothesis”). Using the extensive British Countryside Survey Data, we find that changes to plant occurrence and cover between 1990 and 2007 at 479 British sites do not differ between native and non-native plant species. More than 80% of the plant species that are widespread enough to be sampled are native species; hence, total cover changes have been dominated by native species (total cover increases by native species are more than nine times greater than those by non-native species). This implies that factors other than plant “invasions” are the key drivers of vegetation change. We also find that the diversity of native species is increasing in locations where the diversity of non-native species is increasing, suggesting that high diversities of native and non-native plant species are compatible with one another. We reject the time-to-exclusion hypothesis as the reason why extinctions have not been observed and suggest that non-native plant species are not a threat to floral diversity in Britain. Further research is needed in island-like environments, but we question whether it is appropriate that more than three-quarters of taxa listed globally as invasive species are plants. PMID:25831537

  18. Non-native plants add to the British flora without negative consequences for native diversity.

    PubMed

    Thomas, Chris D; Palmer, G

    2015-04-01

    Plants are commonly listed as invasive species, presuming that they cause harm at both global and regional scales. Approximately 40% of all species listed as invasive within Britain are plants. However, invasive plants are rarely linked to the national or global extinction of native plant species. The possible explanation is that competitive exclusion takes place slowly and that invasive plants will eventually eliminate native species (the "time-to-exclusion hypothesis"). Using the extensive British Countryside Survey Data, we find that changes to plant occurrence and cover between 1990 and 2007 at 479 British sites do not differ between native and non-native plant species. More than 80% of the plant species that are widespread enough to be sampled are native species; hence, total cover changes have been dominated by native species (total cover increases by native species are more than nine times greater than those by non-native species). This implies that factors other than plant "invasions" are the key drivers of vegetation change. We also find that the diversity of native species is increasing in locations where the diversity of non-native species is increasing, suggesting that high diversities of native and non-native plant species are compatible with one another. We reject the time-to-exclusion hypothesis as the reason why extinctions have not been observed and suggest that non-native plant species are not a threat to floral diversity in Britain. Further research is needed in island-like environments, but we question whether it is appropriate that more than three-quarters of taxa listed globally as invasive species are plants. PMID:25831537

  19. A phylogenetic perspective on the distribution of plant diversity

    PubMed Central

    Donoghue, Michael J.

    2008-01-01

    Phylogenetic studies are revealing that major ecological niches are more conserved through evolutionary history than expected, implying that adaptations to major climate changes have not readily been accomplished in all lineages. Phylogenetic niche conservatism has important consequences for the assembly of both local communities and the regional species pools from which these are drawn. If corridors for movement are available, newly emerging environments will tend to be filled by species that filter in from areas in which the relevant adaptations have already evolved, as opposed to being filled by in situ evolution of these adaptations. Examples include intercontinental disjunctions of tropical plants, the spread of plant lineages around the Northern Hemisphere after the evolution of cold tolerance, and the radiation of northern alpine plants into the Andes. These observations highlight the role of phylogenetic knowledge and historical biogeography in explanations of global biodiversity patterns. They also have implications for the future of biodiversity. PMID:18695216

  20. Diversity of heterotrimeric G-protein ? subunits in plants

    PubMed Central

    2012-01-01

    Background Heterotrimeric G-proteins, consisting of three subunits G?, G? and G? are present in most eukaryotes and mediate signaling in numerous biological processes. In plants, G? subunits were shown to provide functional selectivity to G-proteins. Three unconventional G? subunits were recently reported in Arabidopsis, rice and soybean but no structural analysis has been reported so far. Their relationship with conventional G? 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 G? 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 G? subunits into three distinct types. Type A consists of G? 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 G? 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 G? subunits lacking isoprenylation motifs to anchor the G?? dimer to the plasma membrane and propose a new flexible nomenclature for plant G? subunits. Finally, in the light of our new classification, we give a word of caution about the interpretation of G? research in Arabidopsis and its generalization to other plant species. PMID:23113884

  1. Simulated climate-vegetation interaction in semi-arid regions affected by plant diversity

    NASA Astrophysics Data System (ADS)

    Claussen, M.; Bathiany, S.; Brovkin, V.; Kleinen, T.

    2013-11-01

    The end of the African Humid Period between 6,000 and 4,000 years ago was associated with large changes in precipitation and vegetation cover. Sediment records from Lake Yoa, Chad, show a gradual decline in precipitation and fluctuation in vegetation over this interval, and have been suggested to demonstrate a weak interaction between climate and vegetation. However, interpretation of these data has neglected the potential effects of plant diversity on the stability of the climate-vegetation system. Here we use a conceptual model that represents plant diversity in terms of moisture requirement. Some of the plant types simulated are sensitive to changes in precipitation, which alone would lead to an unstable system with the possibility of abrupt changes. Other plants are more resilient, resulting in a stable system that changes gradually. We demonstrate that plant diversity tends to attenuate the instability of the interaction between climate and sensitive plant types, whereas it reduces the stability of the interaction between climate and less-sensitive plant types. Hence, despite large sensitivities of individual plant types to precipitation, a gradual decline in precipitation and shift in mean vegetation cover can occur. However, we suggest that the system could become unstable if some plant types were removed or introduced, leading to an abrupt regime shift.

  2. Appraisal of plant diversity effect of the rebuilding and extension project of National Highway 209 Duchuan to Chunshu section

    NASA Astrophysics Data System (ADS)

    Shi, Youhui; Zhang, Qipeng; Li, Haiyan; Dai, Yan

    2011-02-01

    Plant diversity evaluation of highway construction of nature reserve is one important task in a construction project. I analyze and appraisal the plant diversity problems caused by the rebuilding and extension project of No.209 national highway Duchuan to Chunshuya section from plant species diversity, plant composition characteristics, vegetation type's diversity and national rare and endangered plants in the construction region. The highway reconstruction through the Savage Valley Nature Reserve basically causes no destructive effects on plant diversity, but there are still some negative effects. In this paper, I put forward scientific, reasonable and feasible measures and methods to the plant diversity protection by combining with the natural environment characteristics of the highway construction region.

  3. Phylogenetic diversity of plants alters the effect of species richness on invertebrate herbivory

    PubMed Central

    2013-01-01

    Long-standing ecological theory proposes that diverse communities of plants should experience a decrease in herbivory. Yet previous empirical examinations of this hypothesis have revealed that plant species richness increases herbivory in just as many systems as it decreases it. In this study, I ask whether more insight into the role of plant diversity in promoting or suppressing herbivory can be gained by incorporating information about the evolutionary history of species in a community. In an old field system in southern Ontario, I surveyed communities of plants and measured levels of leaf damage on 27 species in 38 plots. I calculated a measure of phylogenetic diversity (PSE) that encapsulates information about the amount of evolutionary history represented in each of the plots and looked for a relationship between levels of herbivory and both species richness and phylogenetic diversity using a generalized linear mixed model (GLMM) that could account for variation in herbivory levels between species. I found that species richness was positively associated with herbivore damage at the plot-level, in keeping with the results from several other recent studies on this question. On the other hand, phylogenetic diversity was associated with decreased herbivory. Importantly, there was also an interaction between species richness and phylogenetic diversity, such that plots with the highest levels of herbivory were plots which had many species but only if those species tended to be closely related to one another. I propose that these results are the consequence of interactions with herbivores whose diets are phylogenetically specialized (for which I introduce the term cladophage), and how phylogenetic diversity may alter their realized host ranges. These results suggest that incorporating a phylogenetic perspective can add valuable additional insight into the role of plant diversity in explaining or predicting levels of herbivory at a whole-community scale. PMID:23825795

  4. Environmental Quality and Fertility: The Effects of Plant Density, Species Richness, and Plant Diversity on Fertility Limitation *

    PubMed Central

    Brauner-Otto, Sarah R.

    2013-01-01

    The relationship between the environment and population has been of concern for centuries and climate change is making this an even more pressing area of study. In poor rural areas declining environmental conditions may elicit changes in family related behaviors. This paper explores this relationship in rural Nepal looking specifically at how plant density, species richness, and plant diversity are related to women’s fertility limitation behavior. Taking advantage of a unique data set with detailed micro-level environmental measures and individual fertility behavior I link geographically weighted measures of flora at one point in time to women’s later contraceptive use as a way to examine this complex relationship. I find a significant, positive relationship between plant density, species richness, and plant diversity and the timing of contraceptive use. Women in poor environmental conditions are less likely to terminate childbearing, or do so later, and therefore more likely to have larger families. PMID:25593378

  5. INCREASING NATIVE PLANT DIVERSITY IN CRESTED WHEATGRASS STANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass was introduced to North America to improve degraded rangelands and has proven to be a successful revegetation species due to its ease of establishment, strong competitive ability, and grazing tolerance. However, crested wheatgrass may form monotypic stands with low plant diversit...

  6. Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment.

    PubMed

    Scherber, Christoph; Eisenhauer, Nico; Weisser, Wolfgang W; Schmid, Bernhard; Voigt, Winfried; Fischer, Markus; Schulze, Ernst-Detlef; Roscher, Christiane; Weigelt, Alexandra; Allan, Eric; Bessler, Holger; Bonkowski, Michael; Buchmann, Nina; Buscot, François; Clement, Lars W; Ebeling, Anne; Engels, Christof; Halle, Stefan; Kertscher, Ilona; Klein, Alexandra-Maria; Koller, Robert; König, Stephan; Kowalski, Esther; Kummer, Volker; Kuu, Annely; Lange, Markus; Lauterbach, Dirk; Middelhoff, Cornelius; Migunova, Varvara D; Milcu, Alexandru; Müller, Ramona; Partsch, Stephan; Petermann, Jana S; Renker, Carsten; Rottstock, Tanja; Sabais, Alexander; Scheu, Stefan; Schumacher, Jens; Temperton, Vicky M; Tscharntke, Teja

    2010-11-25

    Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades. PMID:20981010

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

    USGS Publications Warehouse

    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. Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada

    USGS Publications Warehouse

    Keeley, J.E.; Lubin, D.; Fotheringham, C.J.

    2003-01-01

    Patterns of native and alien plant diversity in response to disturbance were examined along an elevational gradient in blue oak savanna, chaparral, and coniferous forests. Total species richness, alien species richness, and alien cover declined with elevation, at scales from 1 to 1000 m2. We found no support for the hypothesis that community diversity inhibits alien invasion. At the 1-m2 point scale, where we would expect competitive interactions between the largely herbaceous flora to be most intense, alien species richness as well as alien cover increased with increasing native species richness in all communities. This suggests that aliens are limited not by the number of native competitors, but by resources that affect establishment of both natives and aliens. Blue oak savannas were heavily dominated by alien species and consistently had more alien than native species at the 1-m 2 scale. All of these aliens are annuals, and it is widely thought that they have displaced native bunchgrasses. If true, this means that aliens have greatly increased species richness. Alternatively, there is a rich regional flora of native annual forbs that could have dominated these grasslands prior to displacement by alien grasses. On our sites, livestock grazing increased the number of alien species and alien cover only slightly over that of sites free of livestock grazing for more than a century, indicating some level of permanency to this invasion. In chaparral, both diversity and aliens increased markedly several years after fire. Invasive species are rare in undisturbed shrublands, and alien propagules fail to survive the natural crown fires in these ecosystems. Thus, aliens necessarily must colonize after fire and, as a consequence, time since fire is an important determinant of invasive presence. Blue oak savannas are an important propagule source for alien species because they maintain permanent populations of all alien species encountered in postfire chaparral, and because the vegetation mosaic in this region places them in proximity to chaparral. The speed at which alien propagules reach a burned site and the speed at which the shrublands return to their former closed-canopy condition determine alien invasion. Frequent burning of this vegetation alters the balance in favor of alien invasion. In the higher-elevation coniferous forests, species diversity was a function of fire severity and time since fire. High-intensity fires create gaps that decrease canopy coverage and increase light levels and nutrients for an ephemeral successional flora. Few species have persistent seed banks, so the time since fire is an important determinant of colonization success. There was a highly significant interaction between fire severity and time since fire for understory cover, species richness, and alien richness and cover. Understory was sparse in the first year after fire, particularly in low-severity burns, and increased substantially several years after fire, particularly on high-severity burns. Both fire severity and time since fire affected alien species richness and dominance. Coniferous forests had about one-third as many alien species as the foothill oak savannas, and fewer than half of the species were shared between these communities. Unburned coniferous forests were largely free of alien species, whereas some burned sites had a significant alien presence, which presents a challenge for fire restoration of these forests.

  9. Response of pest control by generalist predators to local-scale plant diversity: a meta-analysis.

    PubMed

    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. PMID:26839684

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

    PubMed

    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 effectively than the other species, suggesting that the choice of plant species may play an important role in facilitating the development of carbon accumulation/storage in created wetlands. Plant community diversity provides many ecosystem services (e.g., habitat and floristic quality) other than carbon storage function. Thus, a further study is needed that will focus on investigating how other design elements such as microtopography and hydrologic connectivity may interact with PD in terms of enhancing the carbon storage potential of newly created wetlands. PMID:26431640

  11. Decoupling factors affecting plant diversity and cover on extensive green roofs.

    PubMed

    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. PMID:24100190

  12. Evolutionary history determines how plant productivity responds to phylogenetic diversity and species richness.

    PubMed

    Genung, Mark A; Schweitzer, Jennifer A; Bailey, Joseph K

    2014-01-01

    The relationship between biodiversity and ecosystem function has received a great deal of attention in ecological research and recent results, from re-analyses, suggest that ecosystem function improves with increases in phylogenetic diversity. However, many of these results have been generalized across a range of different species and clades, and plants with different evolutionary histories could display different relationships between biodiversity and ecosystem function. To experimentally test this hypothesis, we manipulated species richness and phylogenetic diversity using 26 species from two subgenera of the genus Eucalyptus (subgenus Eucalyptus and subgenus Symphyomyrtus). We found that plant biomass (a measurement of ecosystem function) sometimes, but not always, responded to increases in species richness and phylogenetic diversity. Specifically, Symphyomyrtus plants showed a positive response while no comparable effect was observed for Eucalyptus plants, showing that responses to biodiversity can vary across different phylogenetic groups. Our results show that the impacts of evolutionary history may complicate the relationship between the diversity of plant communities and plant biomass. PMID:24688865

  13. Biosynthesis of Plant Volatiles: Nature’s Diversity and Ingenuity

    PubMed Central

    Pichersky, Eran; Noel, Joseph P.; Dudareva, Natalia

    2010-01-01

    Plant volatiles (PVs) are lipophilic molecules with high vapor pressure that serve various ecological roles. The synthesis of PVs involves the removal of hydrophilic moieties and oxidation/hydroxylation, reduction, methylation, and acylation reactions. Some PV biosynthetic enzymes produce multiple products from a single substrate or act on multiple substrates. Genes for PV biosynthesis evolve by duplication of genes that direct other aspects of plant metabolism; these duplicated genes then diverge from each other over time. Changes in the preferred substrate or resultant product of PV enzymes may occur through minimal changes of critical residues. Convergent evolution is often responsible for the ability of distally related species to synthesize the same volatile. PMID:16469917

  14. Genetic diversity and networks of exchange: a combined approach to assess intra-breed diversity

    PubMed Central

    2012-01-01

    Background Cryopreservation of three endangered Belgian sheep breeds required to characterize their intra-breed genetic diversity. It is assumed that the genetic structure of a livestock breed depends mostly on gene flow due to exchanges between herds. To quantify this relation, molecular data and analyses of the exchanges were combined for three endangered Belgian breeds. Methods For each breed, between 91 and 225 sheep were genotyped with 19 microsatellites. Genetic differentiations between breeds and among herds within a breed were evaluated and the genetic structure of the breeds was described using Bayesian clustering (Structure). Exchanges of animals between 20, 46 and 95 herds according to breed were identified via semi-directed interviews and were analyzed using the concepts of the network theory to calculate average degrees and shortest path lengths between herds. Correlation between the Reynolds’ genetic distances and the shortest path lengths between each pair of herds was assessed by a Mantel test approach. Results Genetic differentiation between breeds was high (0.16). Overall Fst values among herds were high in each breed (0.17, 0.11 and 0.10). Use of the Bayesian approach made it possible to identify genetic groups of herds within a breed. Significant correlations between the shortest path lengths and the Reynolds’ genetic distances were found in each breed (0.87, 0.33 and 0.41), which demonstrate the influence of exchanges between herds on the genetic diversity. Correlation differences between breeds could be explained by differences in the average degree of the animal exchange networks, which is a measure of the number of exchanges per herd. The two breeds with the highest average degree showed the lowest correlation. Information from the exchange networks was used to assign individuals to the genetic groups when molecular information was incomplete or missing to identify donors for a cryobank. Conclusions A fine-scale picture of the population genetic structure at the herd level was obtained for the three breeds. Network analysis made it possible to highlight the influence of exchanges on genetic structure and to complete or replace molecular information in establishing a conservation program. PMID:22620856

  15. [Effects of planting transgenic cotton on functional diversity of rhizosphere soil microbial community].

    PubMed

    Ye, Fei; Song, Cun-Jiang; Tao, Jian; Li, Chang-Lin

    2010-02-01

    By the method of Biolog, a comparative study was made on the utilization level of single carbon source by the microbes in the rhizosphere soils of two transgenic cottons and their parents, aimed to approach the effects of planting transgenic cotton on the functional diversity of rhizosphere soil microbial community. Compared with planting non-transgenic cotton, planting transgenic cotton had less effects on the carbon sourceing utilization ability, Shannon functional diversity index, and evenness index of rhizosphere soil microbes at seedling, squaring, boll-opening, and senescence stages, but decreased the carbon source utilization ability and functional diversity index at flowering and boll-forming stage significantly. Principal component analysis (PCA) indicated that there existed greater differentiation in the carbon source utilization by the microbes in rhizosphere soils of nontransgenic and transgenic cottons at flowering and boll-forming stage, suggesting the significant difference in the carbon source utilization pattern of the microbes at this stage. PMID:20462010

  16. Modelling snow cover duration improves predictions of functional and taxonomic diversity for alpine plant communities

    PubMed Central

    Carlson, Bradley Z.; Choler, Philippe; Renaud, Julien; Dedieu, Jean-Pierre; Thuiller, Wilfried

    2015-01-01

    Background and Aims Quantifying relationships between snow cover duration and plant community properties remains an important challenge in alpine ecology. We developed a method to estimate spatial variation in energy availability in the context of a topographically complex, high-elevation watershed, which we used to test the explanatory power of environmental gradients both with and without snow cover in relation to taxonomic and functional plant diversity. Methods We mapped snow cover at 15 m resolution using Landsat imagery for five recent years and fitted a generalized additive model (GAM) for each year linking snow to time and topography. Predicted snow cover maps were combined with air temperature and solar radiation at daily resolution, summed for each year and averaged across years. Equivalent growing season energy gradients were also estimated without accounting for snow cover duration. Relationships were tested between environmental gradients and diversity metrics measured for 100 plots (including species richness, community weighted mean traits, functional diversity and hyperspectral estimates of canopy chlorophyll content). Key Results Accounting for snow cover in environmental variables consistently led to improved predictive power as well as more ecologically meaningful characterizations of plant diversity. Model parameters differed significantly when fitted with and without snow cover. Filtering solar radiation with snow as compared to without led to an average gain in R2 of 0.26 and also reversed slope direction to more intuitive relationships for several diversity metrics. Conclusions We show that in alpine environments, high-resolution data on snow cover duration are pivotal for capturing the spatial heterogeneity of both taxonomic and functional diversity. The use of climate variables without consideration of snow cover can lead to erroneous predictions of plant diversity. Our results further indicate that studies seeking to predict the response of alpine plant communities to climate change need to consider shifts in both temperature and nival regimes. PMID:25851138

  17. Assessing Racial Microaggression Distress in a Diverse Sample.

    PubMed

    Torres-Harding, Susan; Turner, Tasha

    2015-12-01

    Racial microaggressions are everyday subtle or ambiguous racially related insults, slights, mistreatment, or invalidations. Racial microaggressions are a type of perceived racism that may negatively impact the health and well-being of people of color in the United States. This study examined the reliability and validity of the Racial Microaggression Scale distress subscales, which measure the perceived stressfulness of six types of microaggression experiences in a racially and ethnically diverse sample. These subscales exhibited acceptable to good internal consistency. The distress subscales also evidenced good convergent validity; the distress subscales were positively correlated with additional measures of stressfulness due to experiencing microaggressions or everyday discrimination. When controlling for the frequency of one's exposure to microaggression incidents, some racial/ethnic group differences were found. Asian Americans reported comparatively lower distress and Latinos reporting comparatively higher distress in response to Foreigner, Low-Achieving, Invisibility, and Environmental microaggressions. African Americans reported higher distress than the other groups in response to Environmental microaggressions. Results suggest that the Racial Microaggressions Scale distress subscales may aid health professionals in assessing the distress elicited by different types of microaggressions. In turn, this may facilitate diagnosis and treatment planning in order to provide multiculturally competent care for African American, Latino, and Asian American clients. PMID:25237154

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

    PubMed

    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. PMID:15590089

  19. Use of an airborne lidar system to model plant species composition and diversity of Mediterranean oak forests.

    PubMed

    Simonson, William D; Allen, Harriet D; Coomes, David A

    2012-10-01

    Airborne lidar is a remote-sensing tool of increasing importance in ecological and conservation research due to its ability to characterize three-dimensional vegetation structure. If different aspects of plant species diversity and composition can be related to vegetation structure, landscape-level assessments of plant communities may be possible. We examined this possibility for Mediterranean oak forests in southern Portugal, which are rich in biological diversity but also threatened. We compared data from a discrete, first-and-last return lidar data set collected for 31 plots of cork oak (Quercus suber) and Algerian oak (Quercus canariensis) forest with field data to test whether lidar can be used to predict the vertical structure of vegetation, diversity of plant species, and community type. Lidar- and field-measured structural data were significantly correlated (up to r= 0.85). Diversity of forest species was significantly associated with lidar-measured vegetation height (R(2) = 0.50, p < 0.001). Clustering and ordination of the species data pointed to the presence of 2 main forest classes that could be discriminated with an accuracy of 89% on the basis of lidar data. Lidar can be applied widely for mapping of habitat and assessments of habitat condition (e.g., in support of the European Species and Habitats Directive [92/43/EEC]). However, particular attention needs to be paid to issues of survey design: density of lidar points and geospatial accuracy of ground-truthing and its timing relative to acquisition of lidar data. PMID:22731687

  20. Vascular plant abundance and diversity in an alpine heath under observed and simulated global change

    PubMed Central

    Alatalo, Juha M.; Little, Chelsea J.; Jägerbrand, Annika K.; Molau, Ulf

    2015-01-01

    Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment. PMID:25950370

  1. Vascular plant abundance and diversity in an alpine heath under observed and simulated global change.

    PubMed

    Alatalo, Juha M; Little, Chelsea J; Jägerbrand, Annika K; Molau, Ulf

    2015-01-01

    Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment. PMID:25950370

  2. Patterns, determinants and models of woody plant diversity in China.

    PubMed

    Wang, Zhiheng; Fang, Jingyun; Tang, Zhiyao; Lin, Xin

    2011-07-22

    What determines large-scale patterns of species richness remains one of the most controversial issues in ecology. Using the distribution maps of 11 405 woody species in China, we compared the effects of habitat heterogeneity, human activities and different aspects of climate, particularly environmental energy, water-energy dynamics and winter frost, and explored how biogeographic affinities (tropical versus temperate) influence richness-climate relationships. We found that the species richness of trees, shrubs, lianas and all woody plants strongly correlated with each other, and more strongly correlated with the species richness of tropical affinity than with that of temperate affinity. The mean temperature of the coldest quarter was the strongest predictor of species richness, and its explanatory power for species richness was significantly higher for tropical affinity than for temperate affinity. These results suggest that the patterns of woody species richness mainly result from the increasing intensity of frost filtering for tropical species from the equator/lowlands towards the poles/highlands, and hence support the freezing-tolerance hypothesis. A model based on these results was developed, which explained 76-85% of species richness variation in China, and reasonably predicted the species richness of woody plants in North America and the Northern Hemisphere. PMID:21147804

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

    USGS Publications Warehouse

    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.

  4. Relationships between Plant Diversity and the Abundance and α-Diversity of Predatory Ground Beetles (Coleoptera: Carabidae) in a Mature Asian Temperate Forest Ecosystem

    PubMed Central

    Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

    2013-01-01

    A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems. PMID:24376582

  5. Assessing the Effectiveness of Undergraduate Diversity Courses Using the Multicultural Experiences Questionnaire

    ERIC Educational Resources Information Center

    You, Di; Matteo, Elizabeth

    2013-01-01

    The Multicultural Experiences Questionnaire (MEQ) is a validated and easy-to-administer tool for assessing individuals' multicultural competencies (Narvaez & Hill, 2010). The current study examined the utility of the MEQ for assessing the impact of undergraduate diversity courses. A total of 137 students in six university-designated diversity…

  6. Diversity of Riparian Plants among and within Species Shapes River Communities.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to alder, local intraspecific differences via decomposition, algal or invertebrate metrics were not observed consistently among maples. These results emphasize that biodiversity of riparian subsidies at the within and across species scale have the potential to affect aquatic ecosystems, although there are complex species-specific effects. PMID:26539714

  7. Diversity of Riparian Plants among and within Species Shapes River Communities

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to alder, local intraspecific differences via decomposition, algal or invertebrate metrics were not observed consistently among maples. These results emphasize that biodiversity of riparian subsidies at the within and across species scale have the potential to affect aquatic ecosystems, although there are complex species-specific effects. PMID:26539714

  8. Assessment of genetic diversity among faba bean genotypes using agro-morphological and molecular markers.

    PubMed

    Ammar, Megahed H; Alghamdi, Salem S; Migdadi, Hussein M; Khan, Muhammad A; El-Harty, Ehab H; Al-Faifi, Sulieman A

    2015-05-01

    Forty faba bean (Vicia faba L.) genotypes were evaluated for their agro-morphological performance and molecular diversity under Central Region of Saudi Arabia conditions during 2010-11 and 2011-12 seasons. Field performance results showed that faba genotypes exhibited a significant amount of variation for their agro-morphological studied parameters. Giza40 recorded the tallest genotype (139.5 cm), highest number of seeds per plants (100.8), and the highest seed yield per plant (70.8 g). The best performing genotypes were Giza40, FLIP03-014FB, Gazira1 and Goff1. Genetic variability among genotypes was determined using Sequence Related Amplified Polymorphism (SRAP) and Amplified Fragment Length Polymorphism (AFLP) markers. A total of 183 amplified fragments (alleles) and 1758 polymorphic fragments (bands) in SRAP and 202 alleles and 716 bands in AFLP were obtained using six SRAP and four AFLP primer combinations respectively. Polymorphism information content (PIC) values for AFLP and SRAP markers were higher than 0.8, indicating the existence of a considerable amount of genetic diversity among faba tested genotypes. The UPGMA based clustering of faba genotypes was largely based on origin and/or genetic background. Result of cluster analysis based on SRAP showed weak and not significant correlation while, it was highly significant based on AFLP analysis with agro-morphological characters (r = 0.01, p > 0.54 and r = 0.26, p < 0.004 respectively). Combined SRAP and AFLP markers proved to be significantly useful for genetic diversity assessment at molecular level. They exhibited high discrimination power, and were able to distinguish the faba bean genotypes with high efficiency and accuracy levels. PMID:25972757

  9. Assessment of genetic diversity among faba bean genotypes using agro-morphological and molecular markers

    PubMed Central

    Ammar, Megahed H.; Alghamdi, Salem S.; Migdadi, Hussein M.; Khan, Muhammad A.; El-Harty, Ehab H.; Al-Faifi, Sulieman A.

    2015-01-01

    Forty faba bean (Vicia faba L.) genotypes were evaluated for their agro-morphological performance and molecular diversity under Central Region of Saudi Arabia conditions during 2010–11 and 2011–12 seasons. Field performance results showed that faba genotypes exhibited a significant amount of variation for their agro-morphological studied parameters. Giza40 recorded the tallest genotype (139.5 cm), highest number of seeds per plants (100.8), and the highest seed yield per plant (70.8 g). The best performing genotypes were Giza40, FLIP03-014FB, Gazira1 and Goff1. Genetic variability among genotypes was determined using Sequence Related Amplified Polymorphism (SRAP) and Amplified Fragment Length Polymorphism (AFLP) markers. A total of 183 amplified fragments (alleles) and 1758 polymorphic fragments (bands) in SRAP and 202 alleles and 716 bands in AFLP were obtained using six SRAP and four AFLP primer combinations respectively. Polymorphism information content (PIC) values for AFLP and SRAP markers were higher than 0.8, indicating the existence of a considerable amount of genetic diversity among faba tested genotypes. The UPGMA based clustering of faba genotypes was largely based on origin and/or genetic background. Result of cluster analysis based on SRAP showed weak and not significant correlation while, it was highly significant based on AFLP analysis with agro-morphological characters (r = 0.01, p > 0.54 and r = 0.26, p < 0.004 respectively). Combined SRAP and AFLP markers proved to be significantly useful for genetic diversity assessment at molecular level. They exhibited high discrimination power, and were able to distinguish the faba bean genotypes with high efficiency and accuracy levels. PMID:25972757

  10. Assessing phenotypic, biochemical, and molecular diversity in coriander (Coriandrum sativum L.) germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research was conducted to elucidate phenotypic and biochemical diversity in 60 coriander (Coriandrum sativum L.) accessions maintained at the North Central Regional Plant Introduction Station and examine relationships between amplified fragment length polymorphisms (AFLP) and patterns of phenot...

  11. The "hidden diversity" of medicinal plants in northeastern Brazil: diagnosis and prospects for conservation and biological prospecting.

    PubMed

    Cavalcanti, Deyvson Rodrigues; Albuquerque, Ulysses Paulino

    2013-01-01

    Increases in ethnobotanical studies and knowledge in recent decades have led to a greater and more accurate interpretation of the overall patterns related to the use of medicinal plants, allowing for a clear identification of some ecological and cultural phenomena. "Hidden diversity" of medicinal plants refers in the present study to the existence of several species of medicinal plants known by the same vernacular name in a given region. Although this phenomenon has previously been observed in a localized and sporadic manner, its full dimensions have not yet been established. In the present study, we sought to assess the hidden diversity of medicinal plants in northeastern Brazil based on the ethnospecies catalogued by local studies. The results indicate that there are an average of at least 2.78 different species per cataloged ethnospecies in the region. Phylogenetic proximity and its attendant morphological similarity favor the interchangeable use of these species, resulting in serious ecological and sanitary implications as well as a wide range of options for conservation and bioprospecting. PMID:24228056

  12. Nuclear material safeguards for enrichments plants: Part 4, Gas Centrifuge Enrichment Plant: Diversion scenarios and IAEA safeguards activities: Safeguards training course

    SciTech Connect

    Not Available

    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.

  13. Plant diversity and conservation status of Himalayan Region Poonch Valley Azad Kashmir (Pakistan).

    PubMed

    Khan, Muhammad Azam; Khan, Mir Ajab; Hussain, Mazhar; Mujtaba, Ghulam

    2014-09-01

    The plant diversity of Himalayan region has been reduced to greater extent due to environmental degradation and human exploitation. Anthropogenic disturbance was the major factor responsible for fragmentation of forest vegetation into small patches. Little research has been conducted in the Himalayan region of Poonch Valley of North eastern Pakistan with reference to plants biodiversity and its conservation. The present research was carried out to provide a checklist of vegetation for biodiversity conservation. A total of 430 vascular and 5 nonvascular plant species with 5 species of Bryophytes (5 families), 13 species of Pteridophytes (6 families), 4 species of Gymnosperms (1 family) and 413 species of angiosperms (95 families) were enumerated from the Poonch valley Azad Kashmir. The genera were classified into three categories according to the number of species. 25 plant communities with phytosociological parameters and diversity indices were reported. Present study revealed that there were 145 threatened, 30 endangered, 68 vulnerable and 47 rare species. It is recorded that extensive grazing, uprooting of plants and soil slope erosion intensify the environmental problems. Since there is maximum exploitation of vegetation, the valley showed a decline in plant diversity. The study was also indicated that the main threats to the biodiversity are expansion of settlement and army installations in the forest area of the valley. For sustainable use In-situ and Ex-situ conservation, controlled harvesting and afforestation may be the solution. Moreover, forest area should be declared prohibited for settlements and army installations. PMID:25176378

  14. Plant Trait Diversity Buffers Variability in Denitrification Potential over Changes in Season and Soil Conditions

    PubMed Central

    McGill, Bonnie M.; Sutton-Grier, Ariana E.; Wright, Justin P.

    2010-01-01

    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 (NO3?) 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 matter, total inorganic nitrogen, and microbial biomass—none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01). Conclusions/Significance These findings suggest that higher plant functional diversity may support a more constant level of DEA through time, buffering the ecosystem from changes in season and soil conditions. PMID:20661464

  15. Plant Diversity in Live Fences and Pastures, Two Examples from the Mexican Humid Tropics

    NASA Astrophysics Data System (ADS)

    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.

  16. Plant diversity in live fences and pastures, two examples from the Mexican humid tropics.

    PubMed

    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. PMID:24981271

  17. Cyanobacteria diversity and toxicity in a wastewater treatment plant (Portugal).

    PubMed

    Vasconcelos, V M; Pereira, E

    2001-04-01

    Cyanobacteria are common in eutrophic natural waters. Being favoured by warm, stable and nutrient-enriched waters they may constitute an important part of the phytoplankton community in Wastewater Treatment Plants (WWTP). The phytoplankton communities of two ponds (facultative and maturation) of the WWTP of Esmoriz (North Portugal) were studied, with particular importance given to cyanobacteria. Mouse bioassays were performed with cyanobacteria samples during some of the blooms and ELISA assays specific for hepatotoxic microcystins were carried out. During the study period (January-July 1999) cyanobacteria were frequently dominant in the ponds ranging from 15.2 to 99.8% of the total phytoplankton density. The main species were Planktothrix mougeotii, Microcystis aeruginosa and Pseudanabaena mucicola. Mouse bioassays were performed during Oscillatoria bloom period but the results were negative, in spite of the high cyanobacteria biomass. ELISA assays were performed for both ponds but only in the maturation pond positive values were found. Microcystin concentrations (as MCYST-LR equivalents) varied from 2.3 to 56.0 micrograms/l on the margin of the pond and between 1.7 and 4.6 micrograms/l in the outflow of this pond. These values indicate that WWTP may be a source of contamination of water bodies with cyanobacteria toxins. PMID:11268858

  18. Assessment Matters in Higher Education: Choosing and Using Diverse Approaches.

    ERIC Educational Resources Information Center

    Brown, Sally, Ed.; Glasner, Angela, Ed.

    This book presents 16 papers on assessment in higher education grouped into four sections on: first, systems approaches to assessment; second, the effectiveness of innovative assessment; third, assessing practice; and fourth, autonomous assessment. The included papers are: (1) "Institutional Strategies for Assessment" (Sally Brown); (2)…

  19. Highly Diverse Endophytic and Soil Fusarium oxysporum Populations Associated with Field-Grown Tomato Plants

    PubMed Central

    Demers, Jill E.; Gugino, Beth K.

    2014-01-01

    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. PMID:25304514

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

    PubMed

    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. PMID:24649649

  1. Highly diverse endophytic and soil Fusarium oxysporum populations associated with field-grown tomato plants.

    PubMed

    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. PMID:25304514

  2. Burning reveals cryptic plant diversity and promotes coexistence in a California prairie restoration experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grassland and prairie restoration projects in California often result in long-term establishment of only a few native plant species, even when they begin with a diverse seed palette. A likely explanation for the disappearance of certain native species over time is that they are excluded through comp...

  3. PATTERNS OF ALLOZYME DIVERSITY IN THE THREATENED PLANT ERIGERON PARISHII (ASTERACEAE). (R826102)

    EPA Science Inventory

    Thirty-one occurrences of Erigeron parishii, a narrowly endemic plant threatened by mining, were sampled for allozyme diversity. This taxon held considerable genetic variation at the [4 allozyme loci surveyed. Species (e.g., alleles per locus [A] = 4.3 and proportion of polymorph...

  4. Pollinating flies (Diptera): A major contribution to plant diversity and agricultural production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diptera are one of the three largest and most diverse animal groups of the world. As an often neglected, but important group of pollinators, they play a significant role in agrobiodiversity and biodiversity of plants everywhere. Flies are present in almost all habitats and biomes and for many food p...

  5. Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of Amaryllidaceae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive ap...

  6. Diversity of Marine Plants. Man and the Gulf of Mexico Series.

    ERIC Educational Resources Information Center

    Irby, Bobby N., Comp.; And Others

    "Man and the Gulf of Mexico" (MGM) is a marine science curriculum series developed to meet the needs of 10th through 12th grade students in Mississippi and Alabama schools. This MGM unit on the diversity of marine plants is divided into 12 sections. The first section introduces the unit by providing objectives and activities on why people classify…

  7. Diverse lifestyles and strategies of plant pathogenesis encoded in the genomes of eighteen Dothideomycetes fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here for the first time we compare the sequenced genomes of 18 Dothideomycetes to analyze their evolution, genome organization, a...

  8. Diversity and biological activities of endophytic fungi associated with micropropagated medicinal plant Echinacea purpurea (L.) Moench

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Echinacea is one of the top ten selling medicinal herbs in Europe and United States. Commercially available formulations may contain different plant parts of three species (Echinacea purpurea, E. pallida, and E. angustifolia). Our study evaluates the diversity of microbial community associated with ...

  9. Exotic plant traits lead to functional diversity decline in novel ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic species have become common and even dominant in some grasslands forming novel ecosystems because the species in them have no common evolutionary history. Recent work on these novel ecosystems suggest that exotic species contribute to diversity declines. In order to identify the plant traits...

  10. Plant diversity effects on soil microbial functions and enzymes are stronger than warming in a grassland experiment.

    PubMed

    Steinauer, Katja; Tilman, David; Wragg, Peter D; Cesarz, Simone; Cowles, Jane M; Pritsch, Karin; Reich, Peter B; Weisser, Wolfgang W; Eisenhauer, Nico

    2015-01-01

    Anthropogenic changes in biodiversity and atmospheric temperature significantly influence ecosystem processes. However, little is known about potential interactive effects of plant diversity and warming on essential ecosystem properties, such as soil microbial functions and element cycling. We studied the effects of orthogonal manipulations of plant diversity (one, four, and 16 species) and warming (ambient, +1.5 degrees C, and +3 degrees C) on soil microbial biomass, respiration, growth after nutrient additions, and activities of extracellular enzymes in 2011 and 2012 in the BAC (biodiversity and climate) perennial grassland experiment site at Cedar Creek, Minnesota, USA. Focal enzymes are involved in essential biogeochemical processes of the carbon, nitrogen, and phosphorus cycles. Soil microbial biomass and some enzyme activities involved in the C and N cycle increased significantly with increasing plant diversity in both years. In addition, 16-species mixtures buffered warming induced reductions in topsoil water content. We found no interactive effects of plant diversity and warming on soil microbial biomass and growth rates. However, the activity of several enzymes (1,4-beta-glucosidase, 1,4-beta-N-acetylglucosaminidase, phosphatase, peroxidase) depended on interactions between plant diversity and warming with elevated activities of enzymes involved in the C, N, and P cycles at both high plant diversity and high warming levels. Increasing plant diversity consistently decreased microbial biomass-specific enzyme activities and altered soil microbial growth responses to nutrient additions, indicating that plant diversity changed nutrient limitations and/or microbial community composition. In contrast to our expectations, higher plant diversity only buffered temperature effects on soil water content, but not on microbial functions. Temperature effects on some soil enzymes were greatest at high plant diversity. In total, our results suggest that the fundamental temperature ranges of soil microbial communities may be sufficiently broad to buffer their functioning against changes in temperature and that plant diversity may be a dominant control of soil microbial processes in a changing world. PMID:26236895

  11. Effects of Plant Diversity, Functional Group Composition, and Fertilization on Soil Microbial Properties in Experimental Grassland

    PubMed Central

    Strecker, Tanja; Barnard, Romain L.; Niklaus, Pascal A.; Scherer-Lorenzen, Michael; Weigelt, Alexandra; Scheu, Stefan; Eisenhauer, Nico

    2015-01-01

    Background Loss of biodiversity and increased nutrient inputs are two of the most crucial anthropogenic factors driving ecosystem change. Although both received considerable attention in previous studies, information on their interactive effects on ecosystem functioning is scarce. In particular, little is known on how soil biota and their functions are affected by combined changes in plant diversity and fertilization. Methodology/Principal Findings We investigated the effects of plant diversity, functional community composition, and fertilization on the biomass and respiration of soil microbial communities in a long-term biodiversity experiment in semi-natural grassland (Jena Experiment). Plant species richness enhanced microbial basal respiration and microbial biomass, but did not significantly affect microbial specific respiration. In contrast, the presence of legumes and fertilization significantly decreased microbial specific respiration, without altering microbial biomass. The effect of legumes was superimposed by fertilization as indicated by a significant interaction between the presence of legumes and fertilization. Further, changes in microbial stoichiometry (C-to-N ratio) and specific respiration suggest the presence of legumes to reduce N limitation of soil microorganisms and to modify microbial C use efficiency. Conclusions/Significance Our study highlights the role of plant species and functional group diversity as well as interactions between plant community composition and fertilizer application for soil microbial functions. Our results suggest soil microbial stoichiometry to be a powerful indicator of microbial functioning under N limited conditions. Although our results support the notion that plant diversity and fertilizer application independently affect microbial functioning, legume effects on microbial N limitation were superimposed by fertilization, indicating significant interactions between the functional composition of plant communities and nutrient inputs for soil processes. PMID:25938580

  12. Grazing maintains native plant diversity and promotes community stability in an annual grassland.

    PubMed

    Beck, Jared J; Hernández, Daniel L; Pasari, Jae R; Zavaleta, Erika S

    2015-07-01

    Maintaining native biodiversity in grasslands requires management and mitigation of anthropogenic changes that have altered resource availability, grazing regimes, and community composition. In California (USA), high levels of atmospheric nitrogen (N) deposition have facilitated the invasion of exotic grasses, posing a threat to the diverse plant and insect communities endemic to serpentine grasslands. Cattle grazing has been employed to mitigate the consequences of exotic grass invasion, but the ecological effects of grazing in this system are not fully understood. To characterize the effects of realistic N deposition on serpentine plant communities and to evaluate the efficacy of grazing as a management tool, we performed a factorial experiment adding N and excluding large herbivores in California's largest serpentine grassland. Although we observed significant interannual variation in community composition related to climate in our six-year study, exotic cover was consistently and negatively correlated with native plant richness. Sustained low-level N addition did not influence plant community composition, but grazing reduced grass abundance while maintaining greater native forb cover, native plant diversity, and species richness in comparison to plots excluding large herbivores. Furthermore, grazing increased the temporal stability of plant communities by decreasing year-to-year variation in native forb cover, native plant diversity, and native species richness. Taken together, our findings demonstrate that moderate-intensity cattle grazing can be used to restrict the invasive potential of exotic grasses and maintain native plant communities in serpentine grasslands. We hypothesize that the reduced temporal variability in serpentine plant communities managed by grazing may directly benefit populations of the threatened Edith's Bay checkerspot butterfly (Euphydryas editha bayensis). PMID:26485954

  13. Rapid compositional change and significant loss of plant species diversity among Triassic-Jurassic palynofloras in East Greenland

    NASA Astrophysics Data System (ADS)

    Mander, Luke; Kürschner, Wolfram; McElwain, Jennifer

    2010-05-01

    The Triassic-Jurassic (Tr-J; 200Ma) transition coincides with the eruption of massive flood basalts associated with the opening of the Atlantic Ocean. This is thought to have lead to a fourfold increase in palaeoatmospheric carbon dioxide, a consequent rise in global temperatures of between 3 and 6 degrees Celsius, and a rise in atmospheric pollutants such as sulphur dioxide. Recent work has employed either plant macrofossils (mostly leaves) or sporomorphs (pollen and spores) to reconstruct the response of terrestrial vegetation to this episode of major environmental change. Investigations of the macrofossil record at Astartekloft in East Greenland indicate a rapid loss of plant diversity in the Late Rhaetian, culminating in an 80% species turnover at the Tr-J boundary interval. However, evidence for such catastrophic diversity loss is conspicuously absent from the sporomorph record. This fossil group indicates that the Tr-J boundary interval in central and northwest Europe is characterized by compositional change and a transient shift from gymnosperm forests to fern-dominated vegetation. In order to address this uncertainty regarding Tr-J vegetation change according to macrofossils versus sporomorphs, we present an analysis of sporomorph diversity and compositional change across the Tr-J at Astartekloft, East Greenland. Sporomorph diversity was estimated using individual and sample-based rarefaction techniques, and compositional differences between sporomorph samples were assessed using non-metric multidimensional scaling. These analyses reveal that sporomorph assemblages from the Tr-J boundary interval at Astartekloft are between 23 and 27% less taxonomically diverse than other Triassic assemblages, and that this interval is characterized by a dramatic shift in the composition of the standing vegetation. These results are statistically significant and are also unrelated to changes in the environment of deposition. These results indicate that the magnitude of plant diversity loss across the Tr-J in East Greenland is apparently greater in the macrofossil record than the sporomorph record. Comparison of these results with taphonomic work on the representation of different groups of plants in macrofossil and sporomorph records at Astartekloft is used to understand this discrepancy.

  14. [Effects of different removal disturbance intensity on plant diversity of Bursaphelenchus xylophilus-invaded Masson pine community].

    PubMed

    Shi, Juan; Luo, Youqing; Song, Jiying; Yan, Xiaosu; Jiang, Ping; Wang, Yijiao

    2006-07-01

    The study on the plant diversity of Bursaphelenchus xylophilus-invaded Masson pine community under effects of different removal disturbance intensity showed that the species diversity indices (richness, Shannon-Wiener index and evenness) of arbor layer decreased in the sequence of broad-leaved stand after the removal of all infected pine trees in the pure pine stand in Fuyang > lightly infected Masson pine - Schima superba mixed stand in Fuyang > uninfected stand mixture of Masson pine and Castanopsis fargessi as the control > lightly infected pure Masson pine stand in Fuyang > Quercus variables stand formed after selective removal of infected pine trees from a mixed Masson pine and Q. variables stand in Zhoushan Islands > pure young Masson pine stand formed after the removal of all infected pine trees from a pure Masson pine stand > pure Liquidambar formosana stand after the removal of infected pine trees from a pure pine stand in Zhoushan Islands > mixed stand consisted of Pinus thunbergii and the Masson pine in Zhoushan Islands > moderately infected Masson pine stand in Zhoushan Islands. All the three indices of shrub layer did not show any significant differences among different communities, except for the pure pine stand in Zhoushan Island, which were the lowest. The three indices of herb layer were higher in pure young Masson pine, Q. variables stand, and L. formosana stand than in other stands. The Masson pine forest at different geographical situation and with different harm extent had distinct disparity, as well as that in different disturbance degree and restoring manner. The "Index of Disturbing Intensity of Stump and Fallen Woods" or IDISF was created to represent the disturbance degree of tree removal on plant diversity. It was found that for both less and more removal disturbing degree, the relationship between species diversity indices and IDISF followed the "Mid-altitude bulge" theory. Specifically, both excessive and insufficient removal of infected trees would cause the decline of plant species diversity in certain degree. Covariance analysis of IDISF indicated that different IDISF had no significant effects on the species diversity of arbor layer, but had different effects on that of shrub and herb layers, which could be used to assess the changes in species diversity of different Masson pine communities after the invasion of pine wood nematode. PMID:17044484

  15. Assessment of genetic diversity in Indian rice germplasm (Oryza sativa L.): use of random versus trait-linked microsatellite markers.

    PubMed

    Yadav, Sheel; Singh, Ashutosh; Singh, M R; Goel, Nitika; Vinod, K K; Mohapatra, T; Singh, A K

    2013-12-01

    Assessment of genetic diversity in a crop germplasm is a vital part of plant breeding. DNA markers such as microsatellite or simple sequence repeat markers have been widely used to estimate the genetic diversity in rice. The present study was carried out to decipher the pattern of genetic diversity in terms of both phenotypic and genotypic variability, and to assess the efficiency of random vis-á-vis QTL linked/gene based simple sequence repeat markers in diversity estimation. A set of 88 rice accessions that included landraces, farmer's varieties and popular Basmati lines were evaluated for agronomic traits and molecular diversity. The random set of SSR markers included 50 diversity panel markers developed under IRRI's Generation Challenge Programme (GCP) and the trait-linked/gene based markers comprised of 50 SSR markers reportedly linked to yield and related components. For agronomic traits, significant variability was observed, ranging between the maximum for grains/panicle and the minimum for panicle length. The molecular diversity based grouping indicated that varieties from a common centre were genetically similar, with few exceptions. The trait-linked markers gave an average genetic dissimilarity of 0.45 as against that of 0.37 by random markers, along with an average polymorphic information constant value of 0.48 and 0.41 respectively. The correlation between the kinship matrix generated by trait-linked markers and the phenotype based distance matrix (0.29) was higher than that of random markers (0.19). This establishes the robustness of trait-linked markers over random markers in estimating genetic diversity of rice germplasm. PMID:24371175

  16. How grazing and soil quality affect native and exotic plant diversity in Rocky Mountain grasslands

    USGS Publications Warehouse

    Stohlgren, T.J.; Schell, L.D.; Vanden, Heuvel B.

    1999-01-01

    We used multiscale plots to sample vascular plant diversity and soil characteristics in and adjacent to 26 long-term grazing exclosure sites in Colorado, Wyoming, Montana, and South Dakota, USA. The exclosures were 7-60 yr old (31.2 ?? 2.5 yr, mean ?? 1 SE). Plots were also randomly placed in the broader landscape in open rangeland in the same vegetation type at each site to assess spatial variation in grazed landscapes. Consistent sampling in the nine National Parks, Wildlife Refuges, and other management units yielded data from 78 1000-m2 plots and 780 1-m2 subplots. We hypothesized that native species richness would be lower in the exclosures than in grazed sites, due to competitive exclusion in the absence of grazing. We also hypothesized that grazed sites would have higher native and exotic species richness compared to ungrazed areas, due to disturbance (i.e., the intermediate-disturbance hypothesis) and the conventional wisdom that grazing may accelerate weed invasion. Both hypotheses were soundly rejected. Although native species richness in 1-m2 subplots was significantly higher (P < 0.05) in grazed sites, we found nearly identical native or exotic species richness in 1000-m2 plots in exclosures (31.5 ?? 2.5 native and 3.1 ?? 0.5 exotic species), adjacent grazed plots (32.6 ?? 2.8 native and 3.2 ?? 0.6 exotic species), and randomly selected grazed plots (31.6 ?? 2.9 native and 3.2 ?? 0.6 exotic species). We found no significant differences in species diversity (Hill's diversity indices, N1 and N2), evenness (Hill's ratio of evenness, E5), cover of various life-forms (grasses, forbs, and shrubs), soil texture, or soil percentage of N and C between grazed and ungrazed sites at the 1000-m2 plot scale. The species lists of the long-ungrazed and adjacent grazed plots overlapped just 57.9 ?? 2.8%. This difference in species composition is commonly attributed solely to the difference in grazing regimes. However, the species lists between pairs of grazed plots (adjacent and distant 1000-m2 plots) in the same vegetation type overlapped just 48.6 ?? 3.6%, and the ungrazed plots and distant grazed plots overlapped 49.4 ?? 3.6%. Differences in vegetation and soils between grazed and ungrazed sites were minimal in most cases, but soil characteristics and elevation were strongly correlated with native and exotic plant diversity in the study region. For the 78 1000-m2 plots, 59.4% of the variance in total species richness was explained by percentage of silt (coefficient = 0.647, t = 5.107, P < 0.001), elevation (coefficient = 0.012, t = 5.084, P < 0.001), and total foliar cover (coefficient = 0.110, t = 2.104, P < 0.039). Only 12.8% of the variance in exotic species cover (log10cover) was explained by percentage of clay (coefficient = -0.011, t = -2.878, P < 0.005), native species richness (coefficient = -0.011, t = -2.156, P < 0.034), and log10N (coefficient = 2.827, t = 1.860, P < 0.067). Native species cover and exotic species richness and frequency were also significantly positively correlated with percentage of soil N at the 1000-m2 plot scale. Our research led to five broad generalizations about current levels of grazing in these Rocky Mountain grasslands: (1) grazing probably has little effect on native species richness at landscape scales; (2) grazing probably has little effect on the accelerated spread of most exotic plant species at landscape scales; (3) grazing affects local plant species and life-form composition and cover, but spatial variation is considerable; (4) soil characteristics, climate, and disturbances may have a greater effect on plant species diversity than do current levels of grazing; and (5) few plant species show consistent, directional responses to grazing or cessation of grazing.

  17. Historical agriculture alters the effects of fire on understory plant beta diversity.

    PubMed

    Mattingly, W Brett; Orrock, John L; Collins, Cathy D; Brudvig, Lars A; Damschen, Ellen I; Veldman, Joseph W; Walker, Joan L

    2015-02-01

    Land-use legacies are known to shape the diversity and distribution of plant communities, but we lack an understanding of whether historical land use influences community responses to contemporary disturbances. Because human-modified landscapes often bear a history of multiple land-use activities, this contingency can challenge our understanding of land-use impacts on plant diversity. We address this contingency by evaluating how beta diversity (the spatial variability of species composition), an important component of regional biodiversity, is shaped by interactions between historical agriculture and prescribed fire, two prominent disturbances that are often coincident in terrestrial ecosystems. At three study locations spanning 450 km in the southeastern United States, we surveyed longleaf pine woodland understory plant communities across 232 remnant and post-agricultural sites with differing prescribed fire regimes. Our results demonstrate that agricultural legacies are a strong predictor of beta diversity, but the direction of this land-use effect differed among the three study locations. Further, although beta diversity increased with prescribed fire frequency at each study location, this effect was influenced by agricultural land-use history, such that positive fire effects were only documented among sites that lacked a history of agriculture at two of our three study locations. Our study not only highlights the role of historical agriculture in shaping beta diversity in a fire-maintained ecosystem but also illustrates how this effect can be contingent upon fire regime and geographic location. We suggest that interactions among historical and contemporary land-use activities may help to explain dissimilarities in plant communities among sites in human-dominated landscapes. PMID:25411111

  18. Plot shape effects on plant species diversity measurements

    USGS Publications Warehouse

    Keeley, J.E.; Fotheringham, C.J.

    2005-01-01

    Question: Do rectangular sample plots record more plant species than square plots as suggested by both empirical and theoretical studies? Location: Grasslands, shrublands and forests in the Mediterranean-climate region of California, USA. Methods: We compared three 0.1-ha sampling designs that differed in the shape and dispersion of 1-m2 and 100-m2 nested subplots. We duplicated an earlier study that compared the Whittaker sample design, which had square clustered subplots, with the modified Whittaker design, which had dispersed rectangular subplots. To sort out effects of dispersion from shape we used a third design that overlaid square subplots on the modified Whittaker design. Also, using data from published studies we extracted species richness values for 400-m2 subplots that were either square or 1:4 rectangles partially overlaid on each other from desert scrub in high and low rainfall years, chaparral, sage scrub, oak savanna and coniferous forests with and without fire. Results: We found that earlier empirical reports of more than 30% greater richness with rectangles were due to the confusion of shape effects with spatial effects, coupled with the use of cumulative number of species as the metric for comparison. Average species richness was not significantly different between square and 1:4 rectangular sample plots at either 1-or 100-m2. Pairwise comparisons showed no significant difference between square and rectangular samples in all but one vegetation type, and that one exhibited significantly greater richness with squares. Our three intensive study sites appear to exhibit some level of self-similarity at the scale of 400 m2, but, contrary to theoretical expectations, we could not detect plot shape effects on species richness at this scale. Conclusions: At the 0.1-ha scale or lower there is no evidence that plot shape has predictable effects on number of species recorded from sample plots. We hypothesize that for the mediterranean-climate vegetation types studied here, the primary reason that 1:4 rectangles do not sample greater species richness than squares is because species turnover varies along complex environmental gradients that are both parallel and perpendicular to the long axis of rectangular plots. Reports in the literature of much greater species richness recorded for highly elongated rectangular strips than for squares of the same area are not likely to be fair comparisons because of the dramatically different periphery/area ratio, which includes a much greater proportion of species that are using both above and below-ground niche space outside the sample area. ?? IAVS; Opulus Press Uppsala.

  19. Plant community diversity and native plant abundance decline with increasing abundance of an exotic annual grass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic plants are generally considered a serious problem in wildlands around the globe. However, some argue that the impacts of exotic plants have been exaggerated and that biodiversity and other important plant community characteristics are commonly improved with invasion. Thus, disagreement exis...

  20. Functional microbial diversity dynamics in common effluent treatment plants of South Gujarat and hydrocarbon degradation.

    PubMed

    Zaveri, Purvi; Munshi, Nasreen; Vaidya, Alok; Jha, Sanjay; Kumar, G Naresh

    2015-06-01

    Common effluent treatment plants (CETPs) of South Gujarat region, India, process wastewater generated by more than 2500 industries because of the nonfeasibility of processing at the individual industrial unit. This study assessed functional microbial diversity in wastewater samples of CETPs over a geological belt using Ecoplate®, isolation of the most abundant bacteria, and screening for hydrocarbon degradation. The high evenness (EPielou) values (0.9) in almost all samples indicated a highly even community structure. Principal component analysis of carbon source utilization showed a cluster of all inlet samples except E1 and another cluster of all outlet samples; aeration tank community samples were dispersed. In spite of the high richness found in microbial communities, 60 morphologically similar organisms were observed and isolated; 46 out of them were subjected to amplified ribosomal DNA restriction analysis with MboI, HaeIII, and TaqI enzyme, followed by UPGMA clustering. In screening the most abundant bacteria from each cluster, one of the cultures showed a high potential for hydrocarbon degradation and was identified as Pseudomonas citronellolis by 16S rDNA sequencing. Because of its highly adapted inherent nature, this bacterium may help augment the conventional procedure in wastewater treatment and efficiently decrease the organic load. PMID:25925663

  1. Receding Water Line and Interspecific Competition Determines Plant Community Composition and Diversity in Wetlands in Beijing

    PubMed Central

    Wang, Zhengjun; Gong, Huili; Zhang, Jing

    2015-01-01

    Climate and human-induced wetland degradation has accelerated in recent years, not only resulting in reduced ecosystem services but also greatly affecting the composition and diversity of wetland plant communities. To date, the knowledge of the differences in community parameters and their successional trends in degraded wetlands remains scarce. Here based on remote sensing images, geographic information system technology, and statistical methods, we produced a successional gradient map of the Yeyahu Wetland Nature Reserve in Beijing, which has experienced a steady decline in water level in recent decades. In addition, we analyzed community composition and diversity along with each identified gradient. The results showed that community diversity decreases while dominance increases with the progress of succession, with the highest diversity occurring during the early stage of succession. Moreover, the community demonstrates greater similarity among subareas during later successional stages, and the similarity coefficients calculated from the important value (IV) of each species are more accurate. Correlation analysis showed that the impact of soil factors on diversity was not significant at a subarea scale, although these nutrients showed an increasing trend with the community succession. Furthermore, the IVs of the dominant species had a particularly significant impact on diversity, showing a significantly negative correlation with diversity indices and a significantly positive correlation with dominance indices. Further analysis showed that the retreat of water level resulted from sustained drought and local human activities was a major extrinsic driving force resulting in observed differences in the community successional stages, which resulted in differences in community composition and diversity. On the other hand, interspecific competition was the main intrinsic mechanism, which significantly influenced the IVs of the dominant species and community diversity. The results of this study could aid in improving the understanding of community composition, diversity, and its successional trends in degraded wetlands. PMID:25848799

  2. Patterns of genetic diversity in three plant lineages endemic to the Cape Verde Islands

    PubMed Central

    Romeiras, Maria M.; Monteiro, Filipa; Duarte, M. Cristina; Schaefer, Hanno; Carine, Mark

    2015-01-01

    Conservation of plant diversity on islands relies on a good knowledge of the taxonomy, distribution and genetic diversity of species. In recent decades, a combination of morphology- and DNA-based approaches has become the standard for investigating island plant lineages and this has led, in some cases, to the discovery of previously overlooked diversity, including ‘cryptic species’. The flora of the Cape Verde archipelago in the North Atlantic is currently thought to comprise ∼740 vascular plant species, 92 of them endemics. Despite the fact that it is considered relatively well known, there has been a 12 % increase in the number of endemics in the last two decades. Relatively few of the Cape Verde plant lineages have been included in genetic studies so far and little is known about the patterns of diversification in the archipelago. Here we present an updated list for the endemic Cape Verde flora and analyse diversity patterns for three endemic plant lineages (Cynanchum, Globularia and Umbilicus) based on one nuclear (ITS) and four plastid DNA regions. In all three lineages, we find genetic variation. In Cynanchum, we find two distinct haplotypes with no clear geographical pattern, possibly reflecting different ploidy levels. In Globularia and Umbilicus, differentiation is evident between populations from northern and southern islands. Isolation and drift resulting from the small and fragmented distributions, coupled with the significant distances separating the northern and southern islands, could explain this pattern. Overall, our study suggests that the diversity in the endemic vascular flora of Cape Verde is higher than previously thought and further work is necessary to characterize the flora. PMID:25979965

  3. Vegetation types, dominant compositions, woody plant diversity and stand structure in Trishna Wildlife Sanctuary of Northeast India.

    PubMed

    Majumdar, Koushik; Datta, B K

    2015-03-01

    Present study was carried out to assess the vegetation types, diversity and phytosociological status of woody plants in Trishna Wildlife Sanctuary of Tripura, Northeast India. Vegetation data was derived by 25 line transects (10 m wide and 500 m length, each 0.5 ha size). All woody species at >10 cm gbh (Girth at Breast Height) within each plots were measured and counted. A total of six forest types were classified by cluster analysis using Importance Value Index (IVI) of 289 woody species. Species diversity, forest structure and woody community associations were evaluated and discussed. One way ANOVA revealed significant differences in all species diversity measures and stand structure along the forest types. Distribution of stem density at ten different gbh classes showed reverse J-shaped curves. Population status of woody plants was also examined through grouping of all individuals into four population age stages viz. sapling (<30 cm gbh), adult (> or = 30 - <120 cm gbh), mature (>120 - 210 cm gbh) and old (> or =210 cm). To observe dominant composition and species population trend, IVI of top ten dominant species from all forest types were tabulated. The present study suggested that Trishna Wildlife Sanctuary is an important habitat in Tripura from floristic point of view and it should be conserved on priority basis for remaining wildlife endurances and monitor for forest livelihoods products for sustainable biodiversity conservation in this region. PMID:25895264

  4. Sampling and Complementarity Effects of Plant Diversity on Resource Use Increases the Invasion Resistance of Communities

    PubMed Central

    Zhu, Dan H.; Wang, Ping; Zhang, Wei Z.; Yuan, Yue; Li, Bin; Wang, Jiang

    2015-01-01

    Background Although plant diversity is postulated to resist invasion, studies have not provided consistent results, most of which were ascribed to the influences of other covariate environmental factors. Methodology/Principal Findings To explore the mechanisms by which plant diversity influences community invasibility, an experiment was conducted involving grassland sites varying in their species richness (one, two, four, eight, and sixteen species). Light interception efficiency and soil resources (total N, total P, and water content) were measured. The number of species, biomass, and the number of seedlings of the invading species decreased significantly with species richness. The presence of Patrinia scabiosaefolia Fisch. ex Trev. and Mosla dianthera (Buch.-Ham. ex Roxburgh) Maxim. significantly increased the resistance of the communities to invasion. A structural equation model showed that the richness of planted species had no direct and significant effect on invasion. Light interception efficiency had a negative effect on the invasion whereas soil water content had a positive effect. In monocultures, Antenoron filiforme (Thunb.) Rob. et Vaut. showed the highest light interception efficiency and P. scabiosaefolia recorded the lowest soil water content. With increased planted-species richness, a greater percentage of pots showed light use efficiency higher than that of A. filiforme and a lower soil water content than that in P. scabiosaefolia. Conclusions/Significance The results of this study suggest that plant diversity confers resistance to invasion, which is mainly ascribed to the sampling effect of particular species and the complementarity effect among species on resources use. PMID:26556713

  5. Genetic and functional diversity among root-associated psychrotrophic Pseudomonad's isolated from the Himalayan plants.

    PubMed

    Bisht, Shekhar Chandra; Mishra, Pankaj Kumar; Joshi, Gopal Kishna

    2013-09-01

    Out of 534 psychrotrophic bacteria, 12 bacteria were selected on the basis of plant growth promoting activities at 4 °C and identified as Pseudomonas genus. These strains showed high level of genetic polymorphisms based on RAPD and rep-PCR fingerprinting. This genetic variability revealed that isolates belonging to same species were as high as the variability among different species. Further inoculation of these Pseudomonas strains significantly improves root/shoot biomass and nutrients uptake of lentil plant as compared to non-bacterized control after 40 days of seed showing. Agglomerative hierarchical clustering analysis of pot assay results revealed that genetically diverse strains showing the same prototype in functional parameter and representing diverse blueprint of plant growth promoting attributes. Results of present findings explain the huge beneficial microbial resources from root zone of hilly crops of Himalayan region that could be effectively exploited as bio-inoculums for cold climatic condition. PMID:23861148

  6. A comparative study of AMF diversity in annual and perennial plant species from semiarid gypsum soils.

    NASA Astrophysics Data System (ADS)

    Alguacil, M. M.; Torrecillas, E.; Roldán, A.; Díaz, G.; Torres, P.

    2012-04-01

    The arbuscular mycorrhizal fungi (AMF) communities composition regulate plant interactions and determine the structure of plant communities. In this study we analysed the diversity of AMF in the roots of two perennial gypsophyte plant species, Herniaria fruticosa and Senecio auricula, and an annual herbaceous species, Bromus rubens, growing in a gypsum soil from a semiarid area. The objective was to determine whether perennial and annual host plants support different AMF communities in their roots and whether there are AMF species that might be indicators of specific functional plant roles in these ecosystems. The roots were analysed by nested PCR, cloning, sequencing of the ribosomal DNA small subunit region and phylogenetic analysis. Twenty AMF sequence types, belonging to the Glomus group A, Glomus group B, Diversisporaceae, Acaulosporaceae, Archaeosporaceae and Paraglomeraceae, were identified. Both gypsophyte perennial species had differing compositions of the AMF community and higher diversity when compared with the annual species, showing preferential selection by specific AMF sequences types. B. rubens did not show host specificity, sharing the full composition of its AMF community with both perennial plant species. Seasonal variations in the competitiveness of AM fungi could explain the observed differences in AMF community composition, but this is still a working hypothesis that requires the analysis of further data obtained from a higher number of both annual and perennial plant species in order to be fully tested.

  7. RESTORING SPECIES RICHNESS AND DIVERSITY IN A RUSSIAN KNAPWEED (ACROPTILON REPENS)-INFESTED RIPARIAN PLANT COMMUNITY USING HERBICIDES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species richness and diversity are important indicators of ecosystem function and may be related to plant community resistance to invasion by non-indigenous species. Knowledge about the influence of various strategies on species richness and diversity is central to making wise invasive plant manage...

  8. Paramagnetic cellulose DNA isolation improves DNA yield and quality among diverse plant taxa1

    PubMed Central

    Moeller, Jackson R.; Moehn, Nicholas R.; Waller, Donald M.; Givnish, Thomas J.

    2014-01-01

    • Premise of the study: The chemical diversity of land plants ensures that no single DNA isolation method results in high yield and purity with little effort for all species. Here we evaluate a new technique originally developed for forensic science, based on MagnaCel paramagnetic cellulose particles (PMC), to determine its efficacy in extracting DNA from 25 plant species representing 21 families and 15 orders. • Methods and Results: Yield and purity of DNA isolated by PMC, DNeasy Plant Mini Kit (silica column), and cetyltrimethylammonium bromide (CTAB) methods were compared among four individuals for each of 25 plant species. PMC gave a twofold advantage in average yield, and the relative advantage of the PMC method was greatest for samples with the lowest DNA yields. PMC also produced more consistent sample purity based on absorbance ratios at 260:280 and 260:230 nm. • Conclusions: PMC technology is a promising alternative for plant DNA isolation. PMID:25309836

  9. Assessing invasive plant infestation in freshwater wetlands

    NASA Astrophysics Data System (ADS)

    Torbick, Nathan M.

    Recent shifts in wetland ecosystem management goals have directed efforts toward measuring ecological integrity, rather than only using physical and chemical measures of ecosystems as health indicators. Invasive species pose one of the largest threats to wetlands integrity. Resource managers can benefit from improved methods for identifying invasive plant species, assessing infestation, and monitoring control measures. The utilization of advanced remote sensing tools for species-level mapping has been increasing and techniques need to be explored for identifying species of interest and characterizing infestation. The overarching goal of this research was to develop monitoring technologies to map invasive plants and quantify wetland infestation. The first field-level objective was to characterize absorption and reflectance features and assess processing techniques for separating wetland species. The second field-level objective was to evaluate the abilities of a shape filter to identify wetland invasive plant species. The first landscape-level objective was to classify hyperspectral imagery in order to identify invasives of interest. The second landscape-level objective was to quantify infestation within the study area. Field-level hyperspectral data (350-2500nm) were collected for twenty-two wetland plant species in a wetland located in the lower Muskegon River watershed in Michigan, USA. The Jeffries-Matusita distance measure, continuum removal, and a shape-filter were applied to hyperspectral species reflectance data to characterize spectral features. Generally, continuum removal decreased separation distance for the invasive species of interest. Using the shape-filter, Lythrum salicaria, Phragmites australis, and Typha latifolia possessed maximum separation (distinguished from other species) at the near-infrared edge (700nm) and water absorption region (1350nm), the near-infrared down slope (1000 and 1100nm), and the visible/chlorophyll absorption region (500nm) and near-infrared edge (650nm), respectively. Airborne hyperspectral imagery was classified using a two-step approach in order to obtain an optimal map (overall accuracy ˜ 70%). Information in the near-infrared enabled relatively accurate classification for Phragmites australis using the Spectral Angle Mapper algorithm and image-derived training, while Typha latifolia signatures possessed high spectral overlap and required ISODATA clustering techniques. Landscape pattern metrics relate infestation to disturbances and hydrological controls. The highest levels of infestation and infestation patterns coincide with the most substantial levels of hydrological modifications indicating human disturbances are correlated with Typha and Phragmites percentages in the landscape. Overall the approach was successful and increased the level of information ultimately desired by decision makers. The rapidly advancing field of wetland remote sensing science can obtain more meaningful information from hyperspectral imagery; however, the data are challenging to work with and only the most precisely calibrated datasets will provide utility. Combining these data with traditional wetland assessment techniques can substantially advanced goals of preserving and restoring wetland ecosystem integrity.

  10. Shifting grassland plant community structure drives positive interactive effects of warming and diversity on aboveground net primary productivity.

    PubMed

    Cowles, Jane M; Wragg, Peter D; Wright, Alexandra J; Powers, Jennifer S; Tilman, David

    2016-02-01

    Ecosystems worldwide are increasingly impacted by multiple drivers of environmental change, including climate warming and loss of biodiversity. We show, using a long-term factorial experiment, that plant diversity loss alters the effects of warming on productivity. Aboveground primary productivity was increased by both high plant diversity and warming, and, in concert, warming (≈1.5 °C average above and belowground warming over the growing season) and diversity caused a greater than additive increase in aboveground productivity. The aboveground warming effects increased over time, particularly at higher levels of diversity, perhaps because of warming-induced increases in legume and C4 bunch grass abundances, and facilitative feedbacks of these species on productivity. Moreover, higher plant diversity was associated with the amelioration of warming-induced environmental conditions. This led to cooler temperatures, decreased vapor pressure deficit, and increased surface soil moisture in higher diversity communities. Root biomass (0-30 cm) was likewise consistently greater at higher plant diversity and was greater with warming in monocultures and at intermediate diversity, but at high diversity warming had no detectable effect. This may be because warming increased the abundance of legumes, which have lower root : shoot ratios than the other types of plants. In addition, legumes increase soil nitrogen (N) supply, which could make N less limiting to other species and potentially decrease their investment in roots. The negative warming × diversity interaction on root mass led to an overall negative interactive effect of these two global change factors on the sum of above and belowground biomass, and thus likely on total plant carbon stores. In total, plant diversity increased the effect of warming on aboveground net productivity and moderated the effect on root mass. These divergent effects suggest that warming and changes in plant diversity are likely to have both interactive and divergent impacts on various aspects of ecosystem functioning. PMID:26426698

  11. Assessing the effect of disturbances on ectomycorrhiza diversity.

    PubMed

    Iordache, Virgil; Gherghel, Felicia; Kothe, Erika

    2009-02-01

    Ectomycorrhiza (ECM) communities can be described on a species level or on a larger scale at an ecosystem level. Here we show that the species level approach of successional processes in ECM communities is not appropriate for understanding the diversity patterns of ECM communities at contaminated sites. An ecosystem based approach improves predictability since different biotic and abiotic factors are included. However, it still does not take into account the hierarchical structure of the ecosystem. We suggest that diversity patterns of ECMs communities in forests can best be investigated at three levels. This hypothetical approach for investigation can be tested at sites of secondary succession in areas contaminated with metals. Once the diversity patterns are appropriately described by a hierarchical ecosystem approach, to the species level is used to explain these patterns by populational and ecotoxicological mechanisms. PMID:19440391

  12. Assessing the Effect of Disturbances on Ectomycorrhiza Diversity

    PubMed Central

    Iordache, Virgil; Gherghel, Felicia; Kothe, Erika

    2009-01-01

    Ectomycorrhiza (ECM) communities can be described on a species level or on a larger scale at an ecosystem level. Here we show that the species level approach of successional processes in ECM communities is not appropriate for understanding the diversity patterns of ECM communities at contaminated sites. An ecosystem based approach improves predictability since different biotic and abiotic factors are included. However, it still does not take into account the hierarchical structure of the ecosystem. We suggest that diversity patterns of ECMs communities in forests can best be investigated at three levels. This hypothetical approach for investigation can be tested at sites of secondary succession in areas contaminated with metals. Once the diversity patterns are appropriately described by a hierarchical ecosystem approach, to the species level is used to explain these patterns by populational and ecotoxicological mechanisms. PMID:19440391

  13. Nitrogen deposition and multi-dimensional plant diversity at the landscape scale

    PubMed Central

    Roth, Tobias; Kohli, Lukas; Rihm, Beat; Amrhein, Valentin; Achermann, Beat

    2015-01-01

    Estimating effects of nitrogen (N) deposition is essential for understanding human impacts on biodiversity. However, studies relating atmospheric N deposition to plant diversity are usually restricted to small plots of high conservation value. Here, we used data on 381 randomly selected 1?km2 plots covering most habitat types of Central Europe and an elevational range of 2900?m. We found that high atmospheric N deposition was associated with low values of six measures of plant diversity. The weakest negative relation to N deposition was found in the traditionally measured total species richness. The strongest relation to N deposition was in phylogenetic diversity, with an estimated loss of 19% due to atmospheric N deposition as compared with a homogeneously distributed historic N deposition without human influence, or of 11% as compared with a spatially varying N deposition for the year 1880, during industrialization in Europe. Because phylogenetic plant diversity is often related to ecosystem functioning, we suggest that atmospheric N deposition threatens functioning of ecosystems at the landscape scale. PMID:26064640

  14. Reproductive consequences of mate quantity versus mate diversity in a wind-pollinated plant

    NASA Astrophysics Data System (ADS)

    Vandepitte, K.; Roldán-Ruiz, I.; Honnay, O.

    2009-07-01

    Since most pollen travels limited distances in wind-pollinated plants, both the local quantity and diversity of mates may limit female reproductive success. Yet little evidence exists on their relative contribution, despite the importance of viable seed production to population dynamics. To study how variation in female reproductive success is affected by the quantity versus the diversity of surrounding mates contributing pollen, we integrated pollination experiments, data on natural seed set and seed viability, and AFLP genetic marker data in the wind-pollinated dioecious clonal forest herb Mercurialis perennis. Pollination experiments indicated weak quantitative pollen limitation effects on seed set. Among-population crosses showed reduced seed viability, suggesting outbreeding depression due to genetic divergence. Pollination with pollen from a single source did not negatively affect reproductive success. These findings were consistent with results of the survey of natural female reproductive success. Seed set decreased with the distance to males in a female plants' local neighborhood, suggesting a shortage of pollen in isolated female plants, and increased with the degree of local genetic diversity. Spatial isolation to other populations and population size did not affect seed set. None of these variables were related to seed viability. We conclude that pollen movement in M. perennis is likely very limited. Both male proximity and the local degree of genetic diversity influenced female reproductive success.

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

    PubMed

    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 (?AIC) 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 response of taxa with varying biogeographical affinities to climatic factors and MDE. PMID:26488164

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

    PubMed Central

    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 response of taxa with varying biogeographical affinities to climatic factors and MDE. PMID:26488164

  17. Grazer exclusion alters plant spatial organization at multiple scales, increasing diversity

    PubMed Central

    Zhang, Hui; Gilbert, Benjamin; Wang, Wenbin; Liu, Junjie; Zhou, Shurong

    2013-01-01

    Grazing is one of the most important factors influencing community structure and productivity in natural grasslands. Understanding why and how grazing pressure changes species diversity is essential for the preservation and restoration of biodiversity in grasslands. We use heavily grazed subalpine meadows in the Qinghai-Tibetan Plateau to test the hypothesis that grazer exclusion alters plant diversity by changing inter- and intraspecific species distributions. Using recently developed spatial analyses combined with detailed ramet mapping of entire plant communities (91 species), we show striking differences between grazed and fenced areas that emerged at scales of just one meter. Species richness was similar at very small scales (0.0625 m2), but at larger scales diversity in grazed areas fell below 75% of corresponding fenced areas. These differences were explained by differences in spatial distributions; intra- and interspecific associations changed from aggregated at small scales to overdispersed in the fenced plots, but were consistently aggregated in the grazed ones. We conclude that grazing enhanced inter- and intraspecific aggregations and maintained high diversity at small scales, but caused decreased turnover in species at larger scales, resulting in lower species richness. Our study provides strong support to the theoretical prediction that inter- and intraspecific aggregation produces local spatial patterns that scale-up to affect species diversity in a community. It also demonstrates that the impacts of grazing can manifest through this mechanism, lowering diversity by reducing spatial turnover in species. Finally, it highlights the ecological and physiological plant processes that are likely responding to grazing and thereby altering aggregation patterns, providing new insights for monitoring, and mediating the impacts of grazing. PMID:24223294

  18. Mechanisms for increased soil C storage with increasing temporal and spatial plant diversity in Agroecosystems

    NASA Astrophysics Data System (ADS)

    Tiemann, L. K.; Grandy, S.; Marin-Spiotta, E.; Atkinson, E. E.

    2012-12-01

    Generally, there are positive relationships between plant species diversity and net primary production and other key ecosystem functions. However, the effects of aboveground diversity on soil microbial communities and ecosystem processes they mediate, such as soil C sequestration, remain unclear. In this study, we used an 11-y cropping diversity study where increases in diversity have increased crop yields. At the experimental site, temporal diversity is altered using combinations of annual crop rotations, while spatial diversity is altered using cover crop species. We used five treatments ranging in diversity from one to five species consisting of continuous corn with no cover crop or one cover crop and corn-soy-wheat rotations with no cover, one cover or two cover crop species. We collected soils from four replicate plots of each treatment and measured the distribution of mega- (>2 mm), macro- (0.25-2 mm), and micro- (0.053-0.25 mm) aggregates. Within each aggregate size class, we also measured total soil C and N, permanganate oxidizable C (POXC), extracellular enzyme activities (EEA), and microbial community structure with phospholipid fatty acid (PLFA) analysis. We use these data to address the impacts of both rotational and cover crop diversity on soil physical structure, associated microbial community structure and activity and soil C storage. As spatial diversity increased, we found concurrent increases in mega-aggregate abundance as well as increasing soil C in the mega- and micro-aggregates but not macro-aggregates. The proportion of total soil C in each aggregate size class that is relatively labile (POXC) was highest in the micro-aggregates, as was enzyme activity associated with labile C acquisition across all levels of diversity. Enzyme activity associated with more recalcitrant forms of soil C was highest in the mega-aggregate class, also across all diversity levels; however, the ratio of labile to recalcitrant EEA increased with increasing diversity in the mega- and micro-aggregates. In addition, soil N increased with diversity such that microbial C:N EEA simultaneously decreased in mega-aggregates. We also found that cropping diversity has created distinctive soil microbial communities, highlighted by variation in the abundance of gram positive bacteria and Actinomycetes. Further research will help us determine how these changes in community structure with increasing diversity are related to concomitant changes in aggregation and enzyme activities. We suggest that the additional organic matter inputs from cover crops in the high diversity treatments have increased aggregation processes and C pools. While microbial activity has also increased in association with this increased C availability, the activity of recalcitrant and N-acquiring enzymes has declined, suggesting an overall decrease in SOM mineralization with possible increased SOM stabilization. The addition of crop species in rotation (temporal diversity) had minimal influence on any of the measured parameters. We thus conclude that spatial diversity is a more important driver of soil structure and microbial activity, likely due to the high quality organic matter inputs derived from the leguminous cover crops; however, spatial diversity alone did not lead to the same level of C storage potential as mixtures of temporal and spatial diversity.

  19. Interactive effects of landscape history and current management on dispersal trait diversity in grassland plant communities

    PubMed Central

    Purschke, Oliver; Sykes, Martin T; Poschlod, Peter; Michalski, Stefan G; Römermann, Christine; Durka, Walter; Kühn, Ingolf; Prentice, Honor C

    2014-01-01

    Plant communities and their ecosystem functions are expected to be more resilient to future habitat fragmentation and deterioration if the species comprising the communities have a wide range of dispersal and persistence strategies. However, the extent to which the diversity of dispersal and persistence traits in plant communities is determined by the current and historical characteristics of sites and their surrounding landscape has yet to be explored. Using quantitative information on long-distance seed dispersal potential by wind and animals (dispersal in space) and on species' persistence/longevity (dispersal in time), we (i) compared levels of dispersal and persistence trait diversity (functional richness, FRic, and functional divergence, FDiv) in seminatural grassland plant communities with those expected by chance, and (ii) quantified the extent to which trait diversity was explained by current and historical landscape structure and local management history – taking into account spatial and phylogenetic autocorrel. Null model analysis revealed that more grassland communities than expected had a level of trait diversity that was lower or higher than predicted, given the level of species richness. Both the range (FRic) and divergence (FDiv) of dispersal and persistence trait values increased with grassland age. FDiv was mainly explained by the interaction between current grazing intensity and the amount of grassland habitat in the surrounding landscape in 1938. Synthesis. The study suggests that the variability of dispersal and persistence traits in grassland plant communities is driven by deterministic assembly processes, with both history and current management (and their interactions), playing a major role as determinants of trait diversity. While a long continuity of grazing management is likely to have promoted the diversity of dispersal and persistence traits in present-day grasslands, communities in sites that are well grazed at the present day, and were also surrounded by large amounts of grassland in the past, showed the highest diversity of dispersal and persistence strategies. Our results indicate that the historical context of a site within a landscape will influence the extent to which current grazing management is able to maintain a diversity of dispersal and persistence strategies and buffer communities (and their associated functions) against continuing habitat fragmentation. PMID:25506086

  20. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    NASA Astrophysics Data System (ADS)

    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 ?g N2O m-2 d-1, and improved nitrate removal (P < 0.001). The presence of Phalaris arundinacea within a given plant community increased the N2O emission (P < 0.001). The presence of Rumex japonicas had no influence on the N2O emissions (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.

  1. Explaining intraspecific diversity in plant secondary metabolites in an ecological context.

    PubMed

    Moore, Ben D; Andrew, Rose L; Külheim, Carsten; Foley, William J

    2014-02-01

    Plant secondary metabolites (PSMs) are ubiquitous in plants and play many ecological roles. Each compound can vary in presence and/or quantity, and the composition of the mixture of chemicals can vary, such that chemodiversity can be partitioned within and among individuals. Plant ontogeny and environmental and genetic variation are recognized as sources of chemical variation, but recent advances in understanding the molecular basis of variation may allow the future deployment of isogenic mutants to test the specific adaptive function of variation in PSMs. An important consequence of high intraspecific variation is the capacity to evolve rapidly. It is becoming increasingly clear that trait variance linked to both macro- and micro-environmental variation can also evolve and may respond more strongly to selection than mean trait values. This research, which is in its infancy in plants, highlights what could be a missing piece of the picture of PSM evolution. PSM polymorphisms are probably maintained by multiple selective forces acting across many spatial and temporal scales, but convincing examples that recognize the diversity of plant population structures are rare. We describe how diversity can be inherently beneficial for plants and suggest fruitful avenues for future research to untangle the causes and consequences of intraspecific variation. PMID:24117919

  2. Progress Towards an Interdisciplinary Science of Plant Phenology: Building Predictions Across Space, Time and Species Diversity

    NASA Technical Reports Server (NTRS)

    Wolkovich, Elizabeth M.; Cook, Benjamin I.; Davies, T. Jonathan

    2013-01-01

    Climate change has brought renewed interest in the study of plant phenology - the timing of life history events. Data on shifting phenologies with warming have accumulated rapidly, yet research has been comparatively slow to explain the diversity of phenological responses observed across latitudes, growing seasons and species. Here, we outline recent efforts to synthesize perspectives on plant phenology across the fields of ecology, climate science and evolution. We highlight three major axes that vary among these disciplines: relative focus on abiotic versus biotic drivers of phenology, on plastic versus genetic drivers of intraspecific variation, and on cross-species versus autecological approaches. Recent interdisciplinary efforts, building on data covering diverse species and climate space, have found a greater role of temperature in controlling phenology at higher latitudes and for early-flowering species in temperate systems. These efforts have also made progress in understanding the tremendous diversity of responses across species by incorporating evolutionary relatedness, and linking phenological flexibility to invasions and plant performance. Future research with a focus on data collection in areas outside the temperate mid-latitudes and across species' ranges, alongside better integration of how risk and investment shape plant phenology, offers promise for further progress.

  3. Progress towards an interdisciplinary science of plant phenology: building predictions across space, time and species diversity.

    PubMed

    Wolkovich, Elizabeth M; Cook, Benjamin I; Davies, T Jonathan

    2014-03-01

    Climate change has brought renewed interest in the study of plant phenology - the timing of life history events. Data on shifting phenologies with warming have accumulated rapidly, yet research has been comparatively slow to explain the diversity of phenological responses observed across latitudes, growing seasons and species. Here, we outline recent efforts to synthesize perspectives on plant phenology across the fields of ecology, climate science and evolution. We highlight three major axes that vary among these disciplines: relative focus on abiotic versus biotic drivers of phenology, on plastic versus genetic drivers of intraspecific variation, and on cross-species versus autecological approaches. Recent interdisciplinary efforts, building on data covering diverse species and climate space, have found a greater role of temperature in controlling phenology at higher latitudes and for early-flowering species in temperate systems. These efforts have also made progress in understanding the tremendous diversity of responses across species by incorporating evolutionary relatedness, and linking phenological flexibility to invasions and plant performance. Future research with a focus on data collection in areas outside the temperate mid-latitudes and across species' ranges, alongside better integration of how risk and investment shape plant phenology, offers promise for further progress. PMID:24649487

  4. Preparing Teachers for Diverse Learners: Assessing Teacher Candidates' Dispositions

    ERIC Educational Resources Information Center

    Northington, Vera Ann

    2011-01-01

    The National Council for Accreditation for Teacher Education (NCATE) recommended teacher preparation programs measure teacher candidates' disposition toward diverse learners. The conduction of the quantitative cross-sectional survey design utilized the Quick Discrimination Index Survey (QDI), a Likert-type tool that used reversed or negatively…

  5. Preparing Teachers for Diverse Learners: Assessing Teacher Candidates' Dispositions

    ERIC Educational Resources Information Center

    Northington, Vera Ann

    2011-01-01

    The National Council for Accreditation for Teacher Education (NCATE) recommended teacher preparation programs measure teacher candidates' disposition toward diverse learners. The conduction of the quantitative cross-sectional survey design utilized the Quick Discrimination Index Survey (QDI), a Likert-type tool that used reversed or negatively…

  6. Genetic Structure and Molecular Diversity of Cacao Plants Established as Local Varieties for More than Two Centuries: The Genetic History of Cacao Plantations in Bahia, Brazil.

    PubMed

    Santos, Elisa S L; Cerqueira-Silva, Carlos Bernard M; Mori, Gustavo M; Ahnert, Dário; Mello, Durval L N; Pires, José Luis; Corrêa, Ronan X; Souza, Anete P de

    2015-01-01

    Bahia is the most important cacao-producing state in Brazil, which is currently the sixth-largest country worldwide to produce cacao seeds. In the eighteenth century, the Comum, Pará and Maranhão varieties of cacao were introduced into southern Bahia, and their descendants, which are called 'Bahian cacao' or local Bahian varieties, have been cultivated for over 200 years. Comum plants have been used to start plantations in African countries and extended as far as countries in South Asia and Oceania. In Brazil, two sets of clones selected from Bahian varieties and their mutants, the Agronomic Institute of East (SIAL) and Bahian Cacao Institute (SIC) series, represent the diversity of Bahian cacao in germplasm banks. Because the genetic diversity of Bahian varieties, which is essential for breeding programs, remains unknown, the objective of this work was to assess the genetic structure and diversity of local Bahian varieties collected from farms and germplasm banks. To this end, 30 simple sequence repeat (SSR) markers were used to genotype 279 cacao plants from germplasm and local farms. The results facilitated the identification of 219 cacao plants of Bahian origin, and 51 of these were SIAL or SIC clones. Bahian cacao showed low genetic diversity. It could be verified that SIC and SIAL clones do not represent the true diversity of Bahian cacao, with the greatest amount of diversity found in cacao trees on the farms. Thus, a core collection to aid in prioritizing the plants to be sampled for Bahian cacao diversity is suggested. These results provide information that can be used to conserve Bahian cacao plants and applied in breeding programs to obtain more productive Bahian cacao with superior quality and tolerance to major diseases in tropical cacao plantations worldwide. PMID:26675449

  7. Genetic Structure and Molecular Diversity of Cacao Plants Established as Local Varieties for More than Two Centuries: The Genetic History of Cacao Plantations in Bahia, Brazil

    PubMed Central

    Santos, Elisa S. L.; Cerqueira-Silva, Carlos Bernard M.; Mori, Gustavo M.; Ahnert, Dário; Mello, Durval L. N.; Pires, José Luis; Corrêa, Ronan X.; de Souza, Anete P.

    2015-01-01

    Bahia is the most important cacao-producing state in Brazil, which is currently the sixth-largest country worldwide to produce cacao seeds. In the eighteenth century, the Comum, Pará and Maranhão varieties of cacao were introduced into southern Bahia, and their descendants, which are called ‘Bahian cacao’ or local Bahian varieties, have been cultivated for over 200 years. Comum plants have been used to start plantations in African countries and extended as far as countries in South Asia and Oceania. In Brazil, two sets of clones selected from Bahian varieties and their mutants, the Agronomic Institute of East (SIAL) and Bahian Cacao Institute (SIC) series, represent the diversity of Bahian cacao in germplasm banks. Because the genetic diversity of Bahian varieties, which is essential for breeding programs, remains unknown, the objective of this work was to assess the genetic structure and diversity of local Bahian varieties collected from farms and germplasm banks. To this end, 30 simple sequence repeat (SSR) markers were used to genotype 279 cacao plants from germplasm and local farms. The results facilitated the identification of 219 cacao plants of Bahian origin, and 51 of these were SIAL or SIC clones. Bahian cacao showed low genetic diversity. It could be verified that SIC and SIAL clones do not represent the true diversity of Bahian cacao, with the greatest amount of diversity found in cacao trees on the farms. Thus, a core collection to aid in prioritizing the plants to be sampled for Bahian cacao diversity is suggested. These results provide information that can be used to conserve Bahian cacao plants and applied in breeding programs to obtain more productive Bahian cacao with superior quality and tolerance to major diseases in tropical cacao plantations worldwide. PMID:26675449

  8. Characteristics of START assessments completed in mental health jail diversion programs.

    PubMed

    Desmarais, Sarah L; Van Dorn, Richard A; Telford, Robin P; Petrila, John; Coffey, Tim

    2012-01-01

    Many different instruments have been developed to assist in the assessment of risk for violence and other criminal behavior. However, there is limited evidence regarding how these instruments work in the 'real world'. Even less is known about how these instruments might work for assessing risk in jail diversion populations, whether in research or practice. To address these knowledge gaps, the present study examined the characteristics of risk assessments completed by program staff (n=10) on 96 mental health jail diversion clients (72 men and 24 women) using the Short-Term Assessment of Risk and Treatability (START). The findings provide preliminary support for the reliability and validity of START assessments completed in jail diversion programs, the first evidence of the transportability of START outside psychiatric settings, and further evidence regarding the reliability and validity of START assessments completed in the field. They additionally support the consideration of an eighth, general offending risk domain in START assessments. PMID:22807034

  9. Does Land-Use Intensification Decrease Plant Phylogenetic Diversity in Local Grasslands?

    PubMed Central

    Egorov, Eugen; Prati, Daniel; Durka, Walter; Michalski, Stefan; Fischer, Markus; Schmitt, Barbara; Blaser, Stefan; Brändle, Martin

    2014-01-01

    Phylogenetic diversity (PD) has been successfully used as a complement to classical measures of biological diversity such as species richness or functional diversity. By considering the phylogenetic history of species, PD broadly summarizes the trait space within a community. This covers amongst others complex physiological or biochemical traits that are often not considered in estimates of functional diversity, but may be important for the understanding of community assembly and the relationship between diversity and ecosystem functions. In this study we analyzed the relationship between PD of plant communities and land-use intensification in 150 local grassland plots in three regions in Germany. Specifically we asked whether PD decreases with land-use intensification and if so, whether the relationship is robust across different regions. Overall, we found that species richness decreased along land-use gradients the results however differed for common and rare species assemblages. PD only weakly decreased with increasing land-use intensity. The strength of the relationship thereby varied among regions and PD metrics used. From our results we suggest that there is no general relationship between PD and land-use intensification probably due to lack of phylogenetic conservatism in land-use sensitive traits. Nevertheless, we suggest that depending on specific regional idiosyncrasies the consideration of PD as a complement to other measures of diversity can be useful. PMID:25061934

  10. Dynamic Response of Large Wind Power Plant Affected by Diverse Conditions at Individual Turbines

    SciTech Connect

    Elizondo, Marcelo A.; Lu, Shuai; Lin, Guang; Wang, Shaobu

    2014-07-31

    Diverse operating conditions at individual wind turbine generators (WTG) within wind power plants (WPPs) can affect the WPP dynamic response to system faults. For example, individual WTGs can experience diverse terminal voltage and power output caused by different wind direction and speed, affecting the response of protection and control limiters. In this paper, we present a study to investigate the dynamic response of a detailed WPP model under diverse power outputs of its individual WTGs. Wake effect is considered as the reason for diverse power outputs. The diverse WTG power output is evaluated in a test system where a large 168-machine test WPP is connected to the IEEE-39-bus system. The power output from each WTG is derived from a wake effect model that uses realistic statistical data for incoming wind speed and direction. The results show that diverse WTG output due to wake effect can affect the WPP dynamic response activating specialized control in some turbines. In addition, transient stability is affected by exhibiting uncertainty in critical clearing time calculation.

  11. Bottom-up effects of host-plant species diversity and top-down effects of ants interactively increase plant performance

    PubMed Central

    Moreira, Xoaquín; Mooney, Kailen A.; Zas, Rafael; Sampedro, Luis

    2012-01-01

    While plant diversity is well known to increase primary productivity, whether these bottom-up effects are enhanced by reciprocal top-down effects from the third trophic level is unknown. We studied whether pine tree species diversity, aphid-tending ants and their interaction determined plant performance and arthropod community structure. Plant diversity had a positive effect on aphids, but only in the presence of mutualistic ants, leading to a threefold greater number of both groups in the tri-specific cultures than in monocultures. Plant diversity increased ant abundance not only by increasing aphid number, but also by increasing ant recruitment per aphid. The positive effect of diversity on ants in turn cascaded down to increase plant performance; diversity increased plant growth (but not biomass), and this effect was stronger in the presence of ants. Consequently, bottom-up effects of diversity within the same genus and guild of plants, and top-down effects from the third trophic level (predatory ants), interactively increased plant performance. PMID:22951745

  12. Lead exposure and blood pressure among workers in diverse industrial plants in Kenya.

    PubMed

    Were, Faridah H; Moturi, M Charles; Gottesfeld, P; Wafula, Godfrey A; Kamau, Geoffrey N; Shiundu, Paul M

    2014-01-01

    The study evaluated airborne exposures and blood lead (BPb) levels in 233 production workers at six diverse industrial plants in Kenya. Blood and personal breathing zone air samples were collected and analyzed for lead (Pb) using atomic absorption spectroscopy. Blood pressure (BP) levels were measured using a standard mercury sphygmomanometer. The results indicated mean airborne Pb levels ± standard deviation (SD) as follows: 183.2 ± 53.6 μg/m(3) in battery recycling, 133.5 ± 39.6 μg/m(3) in battery manufacturing, 126.2 ± 39.9 μg/m(3) in scrap metal welding, 76.3 ± 33.2 μg/m(3) in paint manufacturing, 27.3 ± 12.1 μg/m(3) in a leather manufacturing, and 5.5 ± 3.6 μg/m(3) in a pharmaceutical plant. The mean airborne Pb levels exceeded the U.S. Occupational Safety and Health Administration (OSHA) 8-hr time-weighted average (TWA) permissible exposure limit (PEL) for Pb of 50 μg/m(3) in the battery manufacturing, battery recycling, welding, and paint manufacturing plants. Similarly, mean BPb concentrations exceeded the American Conference of Governmental Industrial Hygienists (ACGIH®) biological exposure index (BEI) for Pb of 30 μg/dl. A significant positive association was observed between BPb and breathing zone air Pb (R(2) = 0.73, P < 0.001). Approximately 30% of the production workers (N = 233) were in the hypertensive range with an average systolic and diastolic blood pressure (BP) of 134.7 ± 12.7 mmHg and 86.4 ± 8.9 mmHg, respectively. In the multivariate regression analysis, age, duration of work, airborne Pb and BPb levels were significantly associated (P < 0.05) with a change in BP. We recommend improved engineering controls, work practices, and personal hygiene to reduce Pb exposures. In addition, workers should undergo comprehensive medical surveillance to include BPb and BP testing, and airborne Pb assessments in all industries with significant lead exposures. PMID:24690073

  13. Assessing the extent and diversity of riparian ecosystems in Sonora, Mexico

    USGS Publications Warehouse

    Scott, M.L.; Nagler, P.L.; Glenn, E.P.; Valdes-Casillas, C.; Erker, J.A.; Reynolds, E.W.; Shafroth, P.B.; Gomez-Limon, E.; Jones, C.L.

    2009-01-01

    Conservation of forested riparian ecosystems is of international concern. Relatively little is known of the structure, composition, diversity, and extent of riparian ecosystems in Mexico. We used high- and low-resolution satellite imagery from 2000 to 2006, and ground-based sampling in 2006, to assess the spatial pattern, extent, and woody plant composition of riparian forests across a range of spatial scales for the state of Sonora, Mexico. For all 3rd and higher order streams, river bottomlands with riparian forests occupied a total area of 2,301 km2. Where forested bottomlands remained, on average, 34% of the area had been converted to agriculture while 39% remained forested. We estimated that the total area of riparian forest along the principal streams was 897 km2. Including fencerow trees, the total forested riparian area was 944 km2, or 0.5% of the total land area of Sonora. Ground-based sampling of woody riparian vegetation consisted of 92, 50 m radius circular plots. About 79 woody plant species were noted. The most important tree species, based on cover and frequency, were willow species Salix spp. (primarily S. goodingii and S. bonplandiana), mesquite species Prosopis spp. (primarily P. velutina), and Fremont cottonwood Populus fremontii. Woody riparian taxa at the reach scale showed a trend of increasing diversity from north to south within Sonora. Species richness was greatest in the willow-bald cypress Taxodium distichum var. mexicanum-Mexican cottonwood P. mexicana subsp. dimorphia ecosystem. The non-native tamarisk Tamarix spp. was rare, occurring at just three study reaches. Relatively natural stream flow patterns and fluvial disturbance regimes likely limit its establishment and spread. ?? 2008 Springer Science + Business Media BV.

  14. Diversity as a Learning Goal: Challenges in Assessing Knowledge, Skills, and Attitudes

    ERIC Educational Resources Information Center

    Bowers, Pam

    2009-01-01

    At Oklahoma State University (OSU), faculty have defined expectations for students' learning of knowledge, skills, and attitudes about diversity, and have implemented a process to assess students' achievement of the diversity learning goal. As was done for other general education learning goals such as written communication ability and critical…

  15. Preliminary assessment of genetic diversity of Italian honey bees in the USA and Italy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Declining numbers of breeder queens and the concomitant loss of genetic diversity potentially could result in inbreeding and increased susceptibility to pests and disease in honey bees. Genetic diversity of commercial Italian bee colonies in the United States and Italy was assessed using microsatell...

  16. Changing Attitudes over Time: Assessing the Effectiveness of a Workplace Diversity Course

    ERIC Educational Resources Information Center

    Probst, Tahira M.

    2003-01-01

    Diversity is increasing within the United States, and higher education will likely play a key role in preparing people to function in this new environment. This study assessed the effectiveness of a semester-long psychology workplace diversity course at changing student levels of ethnocentrism and attitudes regarding gender roles; the disabled;…

  17. Assessing the Effects of Woody Plant Traits on Understory Herbaceous Cover in a Semiarid Rangeland

    NASA Astrophysics Data System (ADS)

    Belay, Tamrat A.; Moe, Stein R.

    2015-07-01

    The ecological impact of woody plant encroachment in rangeland ecosystems has traditionally been evaluated based on correlation studies between densities of dissimilar woody plants and various ecosystem properties. However, ecosystem properties respond differently to woody plant encroachment because of variations in adaptation of co-occurring woody plants. The objective of this study is to predict the impact of woody plant encroachment on understory herbaceous cover based on analysis of key traits of woody plants. We conducted a vegetation survey in 4 savanna sites in southwestern Ethiopia and compared 9 different key traits of 19 co-occurring woody plants with understory herbaceous cover. Our results show that low understory herbaceous cover is associated with evergreen leaf phenology, shrubby growth form, smaller relative crown-base height and larger relative crown diameter. However, the N2-fixing ability and density of woody plants did not influence the understory herbaceous cover. This shows that traits of individual woody plants can predict the impact of woody plant encroachment on understory herbaceous cover better than density does. The finding improves our ability to accurately predict the impact of woody plant encroachment on various ecosystem properties in highly diverse savanna systems. This plant trait-based approach could be also used as an important management exercise to assess and predict the impact of encroaching woody species in several rangeland ecosystems.

  18. Contemporary Issues in the Assessment of Culturally and Linguistically Diverse Learners

    ERIC Educational Resources Information Center

    Schon, Jacqueline; Shaftel, Julia; Markham, Paul

    2008-01-01

    This article addresses issues faced by school psychologists when assessing students who are culturally and linguistically diverse (CLD). The authors describe the growing CLD population and legal requirements for assessment of CLD students for special education eligibility. Difficulties associated with referral and assessment procedures of CLD…

  19. Should Exotic Eucalyptus be Planted in Subtropical China: Insights from Understory Plant Diversity in Two Contrasting Eucalyptus Chronosequences.

    PubMed

    Wu, Jianping; Fan, Houbao; Liu, Wenfei; Huang, Guomin; Tang, Jianfu; Zeng, Ruijin; Huang, Jing; Liu, Zhanfeng

    2015-11-01

    Although Eucalyptus is widely planted in South China, whose effects on native biodiversity are unclear. The objective of this study was to quantify the richness and composition of understory plants in two contrasting Eucalyptus chronosequences in South China. One was in Zhangzhou City with plantation age of 2, 4, and 6 years after clear-cutting Chinese fir forests, while the other was in Heshan City with plantation age of 2, 3, and 24 years that reforested on barren lands. Results showed that the richness of understory plants and functional groups was not significantly altered in the Zhangzhou chronosequence, while increased in the 24-year-old plantations, with a significantly larger proportion of woody plants than the younger plantations for the Heshan chronosequence. Moreover, a higher richness of woody plants accompanied by a lower richness of herbaceous species was detected in the Zhangzhou chronosequence compared with the Heshan one. To balance the need for pulp production and plant diversity conservation, we suggest that intercropping approaches between exotic Eucalyptus plantations and native forests should be considered in the fast rotation Eucalyptus plantations. However, Eucalyptus plantations may be used as pioneer species to sustain ecosystem functioning for the degraded lands. PMID:26239647

  20. Should Exotic Eucalyptus be Planted in Subtropical China: Insights from Understory Plant Diversity in Two Contrasting Eucalyptus Chronosequences

    NASA Astrophysics Data System (ADS)

    Wu, Jianping; Fan, Houbao; Liu, Wenfei; Huang, Guomin; Tang, Jianfu; Zeng, Ruijin; Huang, Jing; Liu, Zhanfeng

    2015-11-01

    Although Eucalyptus is widely planted in South China, whose effects on native biodiversity are unclear. The objective of this study was to quantify the richness and composition of understory plants in two contrasting Eucalyptus chronosequences in South China. One was in Zhangzhou City with plantation age of 2, 4, and 6 years after clear-cutting Chinese fir forests, while the other was in Heshan City with plantation age of 2, 3, and 24 years that reforested on barren lands. Results showed that the richness of understory plants and functional groups was not significantly altered in the Zhangzhou chronosequence, while increased in the 24-year-old plantations, with a significantly larger proportion of woody plants than the younger plantations for the Heshan chronosequence. Moreover, a higher richness of woody plants accompanied by a lower richness of herbaceous species was detected in the Zhangzhou chronosequence compared with the Heshan one. To balance the need for pulp production and plant diversity conservation, we suggest that intercropping approaches between exotic Eucalyptus plantations and native forests should be considered in the fast rotation Eucalyptus plantations. However, Eucalyptus plantations may be used as pioneer species to sustain ecosystem functioning for the degraded lands.

  1. Soil fertility and plant diversity enhance microbial performance in metal-polluted soils.

    PubMed

    Stefanowicz, Anna M; Kapusta, Pawe?; Szarek-?ukaszewska, Gra?yna; Grodzi?ska, Krystyna; Nikli?ska, Maria; Vogt, Rolf D

    2012-11-15

    This study examined the effects of soil physicochemical properties (including heavy metal pollution) and vegetation parameters on soil basal respiration, microbial biomass, and the activity and functional richness of culturable soil bacteria and fungi. In a zinc and lead mining area (S Poland), 49 sites were selected to represent all common plant communities and comprise the area's diverse soil types. Numerous variables describing habitat properties were reduced by PCA to 7 independent factors, mainly representing subsoil type (metal-rich mining waste vs. sand), soil fertility (exchangeable Ca, Mg and K, total C and N, organic C), plant species richness, phosphorus content, water-soluble heavy metals (Zn, Cd and Pb), clay content and plant functional diversity (based on graminoids, legumes and non-leguminous forbs). Multiple regression analysis including these factors explained much of the variation in most microbial parameters; in the case of microbial respiration and biomass, it was 86% and 71%, respectively. The activity of soil microbes was positively affected mainly by soil fertility and, apparently, by the presence of mining waste in the subsoil. The mining waste contained vast amounts of trace metals (total Zn, Cd and Pb), but it promoted microbial performance due to its inherently high content of macronutrients (total Ca, Mg, K and C). Plant species richness had a relatively strong positive effect on all microbial parameters, except for the fungal component. In contrast, plant functional diversity was practically negligible in its effect on microbes. Other explanatory variables had only a minor positive effect (clay content) or no significant influence (phosphorus content) on microbial communities. The main conclusion from this study is that high nutrient availability and plant species richness positively affected the soil microbes and that this apparently counteracted the toxic effects of metal contamination. PMID:23073370

  2. [Diversity of bacterial community in rhizosphere soils under effects of continuously planting burley tobacco].

    PubMed

    Chen, Dong-mei; Ke, Wen-hui; Chen, Lan-lan; Huang, Jin-wen; Wu, Wen-xiang; Chen, Ting; Zhang, Zhong-yi; Lin, Wen-xiong

    2010-07-01

    By using T-RFLP approach, this paper studied the dynamic changes of bacterial community in the rhizosphere soils under continuously planting burley tobacco for 1, 2 and 4 years. With the increasing of continuous planting years, the Shannon index and Margalef index of bacterial community in the rhizosphere soils decreased after an initial increase. After 4-year continuous planting, the diversity of the bacterial community decreased significantly, and the community structure became simple. The similarity coefficient of the bacterial community in the rhizosphere soils of continuously planting burley tobacco for 1 and 2 years and of the control was decreased with increasing year of continuous planting. Actinobacteria were predominant in the soils under 1 and 2 years continuous planting and in the control, but decreased in the soil continuously planted with burley tobacco for 4 years, in which, Bacilli of Firmicute was the dominant. It was suggested that continuously planting burley tobacco could result in the decrease of beneficial microbes such as Sphingomonas and Streptomyces while increase the species of pathogenic bacteria such as Bacillus cereus in rhizosphere soil, which in return, could lead to the imbalance of bacterial community and deteriorate the micro-ecological conditions in rhizosphere soil. PMID:20879533

  3. Natural Products from Plant-associated Microorganisms: Distribution, Structural Diversity, Bioactivity, and Implications of Their Occurrence⊥

    PubMed Central

    Gunatilaka, A. A. Leslie

    2012-01-01

    A growing body of evidence suggests that plant-associated microorganisms, especially endophytic and rhizosphere bacteria and fungi, represent a huge and largely untapped resource of natural products with chemical structures that have been optimized by evolution for biological and ecological relevance. A diverse array of bioactive small molecule natural products has been encountered in these microorganisms. The structures of over 230 metabolites isolated and characterized from over 70 plant-associated microbial strains during the past four years are presented with information on their hosts, culture conditions, and biological activities. Some significant biological and ecological implications of their occurrence are also reviewed. PMID:16562864

  4. The PathoChip, a functional gene array for assessing pathogenic properties of diverse microbial communities.

    PubMed

    Lee, Yong-Jin; van Nostrand, Joy D; Tu, Qichao; Lu, Zhenmei; Cheng, Lei; Yuan, Tong; Deng, Ye; Carter, Michelle Q; He, Zhili; Wu, Liyou; Yang, Fang; Xu, Jian; Zhou, Jizhong

    2013-10-01

    Pathogens present in the environment pose a serious threat to human, plant and animal health as evidenced by recent outbreaks. As many pathogens can survive and proliferate in the environment, it is important to understand their population dynamics and pathogenic potential in the environment. To assess pathogenic potential in diverse habitats, we developed a functional gene array, the PathoChip, constructed with key virulence genes related to major virulence factors, such as adherence, colonization, motility, invasion, toxin, immune evasion and iron uptake. A total of 3715 best probes were selected from 13 virulence factors, covering 7417 coding sequences from 1397 microbial species (2336 strains). The specificity of the PathoChip was computationally verified, and approximately 98% of the probes provided specificity at or below the species level, proving its excellent capability for the detection of target sequences with high discrimination power. We applied this array to community samples from soil, seawater and human saliva to assess the occurrence of virulence genes in natural environments. Both the abundance and diversity of virulence genes increased in stressed conditions compared with their corresponding controls, indicating a possible increase in abundance of pathogenic bacteria under environmental perturbations such as warming or oil spills. Statistical analyses showed that microbial communities harboring virulence genes were responsive to environmental perturbations, which drove changes in abundance and distribution of virulence genes. The PathoChip provides a useful tool to identify virulence genes in microbial populations, examine the dynamics of virulence genes in response to environmental perturbations and determine the pathogenic potential of microbial communities. PMID:23765101

  5. Genotypic and phenotypic diversity of Bacillus spp. isolated from steel plant waste

    PubMed Central

    Freitas, Dulcecleide B; Reis, Mariana P; Lima-Bittencourt, Cláudia I; Costa, Patrícia S; Assis, Paulo S; Chartone-Souza, Edmar; Nascimento, Andréa MA

    2008-01-01

    Background Molecular studies of Bacillus diversity in various environments have been reported. However, there have been few investigations concerning Bacillus in steel plant environments. In this study, genotypic and phenotypic diversity and phylogenetic relationships among 40 bacterial isolates recovered from steel plant waste were investigated using classical and molecular methods. Results 16S rDNA partial sequencing assigned all the isolates to the Bacillus genus, with close genetic relatedness to the Bacillus subtilis and Bacillus cereus groups, and to the species Bacillus sphaericus. tDNA-intergenic spacer length polymorphisms and the 16S–23S intergenic transcribed spacer region failed to identify the isolates at the species level. Genomic diversity was investigated by molecular typing with rep (repetitive sequence) based PCR using the primer sets ERIC2 (enterobacterial repetitive intergenic consensus), (GTG)5, and BOXAIR. Genotypic fingerprinting of the isolates reflected high intraspecies and interspecies diversity. Clustering of the isolates using ERIC-PCR fingerprinting was similar to that obtained from the 16S rRNA gene phylogenetic tree, indicating the potential of the former technique as a simple and useful tool for examining relationships among unknown Bacillus spp. Physiological, biochemical and heavy metal susceptibility profiles also indicated considerable phenotypic diversity. Among the heavy metal compounds tested Zn, Pb and Cu were least toxic to the bacterial isolates, whereas Ag inhibited all isolates at 0.001 mM. Conclusion Isolates with identical 16S rRNA gene sequences had different genomic fingerprints and differed considerably in their physiological capabilities, so the high levels of phenotypic diversity found in this study are likely to have ecological relevance. PMID:18928552

  6. Assessing uniformity in soil plant atmosphere chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growth chambers provide precisely controlled environments in which to grow plants and evaluate the effects of one or more controllable parameters on plant responses. Because of this precise control, it is arguable that less plant replication is required in growth chamber versus field studies. Howe...

  7. A new image of plantain diversity assessed by SSR, AFLP and MSAP markers.

    PubMed

    Noyer, J L; Causse, S; Tomekpe, K; Bouet, A; Baurens, F C

    2005-05-01

    Using both SSR and AFLP markers, the genetic diversity of 30 plantains constituting a representative sample of the phenotypic diversity was assessed. The results confirmed a very narrow genetic base of this cultivar group. SSR and AFLP data support the hypothesis that these cultivars may have arisen from vegetative multiplication of a single seed. MSAP were used to survey cytosine methylation status at CCGG sites in order to obtain an alternative source of diversity data. A higher degree of polymorphism was revealed allowing the classification of the samples into three clusters. No correlation was observed between the phenotypic classification and methylation diversity. Implications for breeding programs are discussed. PMID:16011003

  8. Diversity of alkane hydroxylase genes on the rhizoplane of grasses planted in petroleum-contaminated soils.

    PubMed

    Tsuboi, Shun; Yamamura, Shigeki; Nakajima-Kambe, Toshiaki; Iwasaki, Kazuhiro

    2015-01-01

    The study investigated the diversity and genotypic features of alkane hydroxylase genes on rhizoplanes of grasses planted in artificial petroleum-contaminated soils to acquire new insights into the bacterial communities responsible for petroleum degradation in phytoremediation. Four types of grass (Cynodon dactylon, two phenotypes of Zoysia japonica, and Z. matrella) were used. The concentrations of total petroleum hydrocarbon effectively decreased in the grass-planted systems compared with the unplanted system. Among the representative alkane hydroxylase genes alkB, CYP153, almA and ladA, the first two were detected in this study, and the genotypes of both genes were apparently different among the systems studied. Their diversity was also higher on the rhizoplanes of the grasses than in unplanted oil-contaminated soils. Actinobacteria-related genes in particular were among the most diverse alkane hydroxylase genes on the rhizoplane in this study, indicating that they are one of the main contributors to degrading alkanes in oil-contaminated soils during phytoremediation. Actinobacteria-related alkB genes and CYP153 genes close to the genera Parvibaculum and Aeromicrobium were found in significant numbers on the rhizoplanes of grasses. These results suggest that the increase in diversity and genotype differences of the alkB and CYP153 genes are important factors affecting petroleum hydrocarbon-degrading ability during phytoremediation. PMID:26405645

  9. An explanation for conflicting records of Triassic-Jurassic plant diversity.

    PubMed

    Mander, Luke; Kürschner, Wolfram M; McElwain, Jennifer C

    2010-08-31

    Macrofossils (mostly leaves) and sporomorphs (pollen and spores) preserve conflicting records of plant biodiversity during the end-Permian (P-Tr), Triassic-Jurassic (Tr-J), and end-Cretaceous (K-T) mass extinctions. Estimates of diversity loss based on macrofossils are typically much higher than estimates of diversity loss based on sporomorphs. Macrofossils from the Tr-J of East Greenland indicate that standing species richness declined by as much as 85% in the Late Triassic, whereas sporomorph records from the same region, and from elsewhere in Europe, reveal little evidence of such catastrophic diversity loss. To understand this major discrepancy, we have used a new high-resolution dataset of sporomorph assemblages from Astartekløft, East Greenland, to directly compare the macrofossil and sporomorph records of Tr-J plant biodiversity. Our results show that sporomorph assemblages from the Tr-J boundary interval are 10-12% less taxonomically diverse than sporomorph assemblages from the Late Triassic, and that vegetation composition changed rapidly in the boundary interval as a result of emigration and/or extirpation of taxa rather than immigration and/or origination of taxa. An analysis of the representation of different plant groups in the macrofossil and sporomorph records at Astartekløft reveals that reproductively specialized plants, including cycads, bennettites and the seed-fern Lepidopteris are almost absent from the sporomorph record. These results provide a means of reconciling the macrofossil and sporomorph records of Tr-J vegetation change, and may help to understand vegetation change during the P-Tr and K-T mass extinctions and around the Paleocene-Eocene Thermal Maximum. PMID:20713737

  10. Incorporating biodiversity into rangeland health: Plant species richness and diversity in great plains grasslands

    USGS Publications Warehouse

    Symstad, A.J.; Jonas, J.L.

    2011-01-01

    Indicators of rangeland health generally do not include a measure of biodiversity. Increasing attention to maintaining biodiversity in rangelands suggests that this omission should be reconsidered, and plant species richness and diversity are two metrics that may be useful and appropriate. Ideally, their response to a variety of anthropogenic and natural drivers in the ecosystem of interest would be clearly understood, thereby providing a means to diagnose the cause of decline in an ecosystem. Conceptual ecological models based on ecological principles and hypotheses provide a framework for this understanding, but these models must be supported by empirical evidence if they are to be used for decision making. To that end, we synthesize results from published studies regarding the responses of plant species richness and diversity to drivers that are of management concern in Great Plains grasslands, one of North America's most imperiled ecosystems. In the published literature, moderate grazing generally has a positive effect on these metrics in tallgrass prairie and a neutral to negative effect in shortgrass prairie. The largest published effects on richness and diversity were caused by moderate grazing in tallgrass prairies and nitrogen fertilization in shortgrass prairies. Although weather is often cited as the reason for considerable annual fluctuations in richness and diversity, little information about the responses of these metrics to weather is available. Responses of the two metrics often diverged, reflecting differences in their sensitivity to different types of changes in the plant community. Although sufficient information has not yet been published for these metrics to meet all the criteria of a good indicator in Great Plains Grasslands, augmenting current methods of evaluating rangeland health with a measure of plant species richness would reduce these shortcomings and provide information critical to managing for biodiversity. ?? Society for Range Management.

  11. An explanation for conflicting records of Triassic–Jurassic plant diversity

    PubMed Central

    Mander, Luke; Kürschner, Wolfram M.; McElwain, Jennifer C.

    2010-01-01

    Macrofossils (mostly leaves) and sporomorphs (pollen and spores) preserve conflicting records of plant biodiversity during the end-Permian (P-Tr), Triassic–Jurassic (Tr-J), and end-Cretaceous (K-T) mass extinctions. Estimates of diversity loss based on macrofossils are typically much higher than estimates of diversity loss based on sporomorphs. Macrofossils from the Tr-J of East Greenland indicate that standing species richness declined by as much as 85% in the Late Triassic, whereas sporomorph records from the same region, and from elsewhere in Europe, reveal little evidence of such catastrophic diversity loss. To understand this major discrepancy, we have used a new high-resolution dataset of sporomorph assemblages from Astartekløft, East Greenland, to directly compare the macrofossil and sporomorph records of Tr-J plant biodiversity. Our results show that sporomorph assemblages from the Tr-J boundary interval are 10–12% less taxonomically diverse than sporomorph assemblages from the Late Triassic, and that vegetation composition changed rapidly in the boundary interval as a result of emigration and/or extirpation of taxa rather than immigration and/or origination of taxa. An analysis of the representation of different plant groups in the macrofossil and sporomorph records at Astartekløft reveals that reproductively specialized plants, including cycads, bennettites and the seed-fern Lepidopteris are almost absent from the sporomorph record. These results provide a means of reconciling the macrofossil and sporomorph records of Tr-J vegetation change, and may help to understand vegetation change during the P-Tr and K-T mass extinctions and around the Paleocene–Eocene Thermal Maximum. PMID:20713737

  12. How do soil texture, plant community composition and earthworms affected the infiltration rate in a grassland plant diversity experiment depending on season?

    NASA Astrophysics Data System (ADS)

    Fischer, Christine; Britta, Merkel; Nico, Eisenhauer; Christiane, Roscher; Sabine, Attinger; Stefan, Scheu; Anke, Hildebrandt

    2013-04-01

    Background and aims: In this study we analyzed the influences of plant community characteristics, soil texture and earthworm presence on infiltration rates on a managed grassland plant diversity experiment assessing the role of biotic and abiotic factors on soil hydrology. Methods: We measured infiltration using a hood infiltrometer in subplots with ambient and reduced earthworm density (earthworm extraction) nested in plots of different plant species richness (1, 4, and 16), plant functional group number and composition (1 to 4; legumes, grasses, small herbs, tall herbs) in early summer (June) and autumn (September, October) 2011. Results: The presence of certain plant functional groups such as grasses and legumes influenced infiltration rates and this effect enhanced during the growing season. Infiltration was significantly higher in plots containing legumes than in plots without, and it was significantly lower in the presence of grasses than in their absence. In early summer, earthworm presence and biomass increased the infiltration rates, independently of plant species richness. In October, plant species richness only affected infiltration rates in reduced earthworm plots. At the end of the growing season earthworm populations were negatively influenced by grasses and positively by legumes. In September, infiltration rates were positive related to the proportion of finer grains. The correlation disappears when removing all plots containing legumes from the sample. For all measurements the infiltration rates decreases from early summer to autumn at the matric potentials at pressure zero and -0.02 m, but not for smaller macropores at matric potentials -0.04 and -0.06m. Conclusions: Considering infiltration rates as ecosystem function, this function will largely depend on the ecosystem composition and season, not on biodiversity per se. Our results indicate that biotic factors are of overriding influence for shaping infiltration rates mainly for larger macropores, and should be taken into account in hydrological applications.

  13. Effects of Previous Land-Use on Plant Species Composition and Diversity in Mediterranean Forests.

    PubMed

    Kouba, Yacine; Martínez-García, Felipe; de Frutos, Ángel; Alados, Concepción L

    2015-01-01

    At some point in their history, most forests in the Mediterranean Basin have been subjected to intensive management or converted to agriculture land. Knowing how forest plant communities recovered after the abandonment of forest-management or agricultural practices (including livestock grazing) provides a basis for investigating how previous land management have affected plant species diversity and composition in forest ecosystems. Our study investigated the consequences of historical "land management" practices on present-day Mediterranean forests by comparing species assemblages and the diversity of (i) all plant species and (ii) each ecological group defined by species' habitat preferences and successional status (i.e., early-, mid-, and late-successional species). We compared forest stands that differed both in land-use history and in successional stage. In addition, we evaluated the value of those stands for biodiversity conservation. The study revealed significant compositional differentiation among stands that was due to among-stand variations in the diversity (namely, species richness and evenness) of early-, intermediate-, and late-successional species. Historical land management has led to an increase in compositional divergences among forest stands and the loss of late-successional forest species. PMID:26397707

  14. Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of amaryllidaceae

    PubMed Central

    2012-01-01

    Background During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive approach enabling more efficient selection of plants for the development of traditional medicine and lead discovery. However, this relationship has rarely been rigorously tested and the potential predictive power is consequently unknown. Results We produced a phylogenetic hypothesis for the medicinally important plant subfamily Amaryllidoideae (Amaryllidaceae) based on parsimony and Bayesian analysis of nuclear, plastid, and mitochondrial DNA sequences of over 100 species. We tested if alkaloid diversity and activity in bioassays related to the central nervous system are significantly correlated with phylogeny and found evidence for a significant phylogenetic signal in these traits, although the effect is not strong. Conclusions Several genera are non-monophyletic emphasizing the importance of using phylogeny for interpretation of character distribution. Alkaloid diversity and in vitro inhibition of acetylcholinesterase (AChE) and binding to the serotonin reuptake transporter (SERT) are significantly correlated with phylogeny. This has implications for the use of phylogenies to interpret chemical evolution and biosynthetic pathways, to select candidate taxa for lead discovery, and to make recommendations for policies regarding traditional use and conservation priorities. PMID:22978363

  15. Effects of Previous Land-Use on Plant Species Composition and Diversity in Mediterranean Forests

    PubMed Central

    Kouba, Yacine; Martínez-García, Felipe; de Frutos, Ángel; Alados, Concepción L.

    2015-01-01

    At some point in their history, most forests in the Mediterranean Basin have been subjected to intensive management or converted to agriculture land. Knowing how forest plant communities recovered after the abandonment of forest-management or agricultural practices (including livestock grazing) provides a basis for investigating how previous land management have affected plant species diversity and composition in forest ecosystems. Our study investigated the consequences of historical “land management” practices on present-day Mediterranean forests by comparing species assemblages and the diversity of (i) all plant species and (ii) each ecological group defined by species’ habitat preferences and successional status (i.e., early-, mid-, and late-successional species). We compared forest stands that differed both in land-use history and in successional stage. In addition, we evaluated the value of those stands for biodiversity conservation. The study revealed significant compositional differentiation among stands that was due to among-stand variations in the diversity (namely, species richness and evenness) of early-, intermediate-, and late-successional species. Historical land management has led to an increase in compositional divergences among forest stands and the loss of late-successional forest species. PMID:26397707

  16. An assessment of restoration success to forests planted for ecosystem restoration in loess plateau, Northwestern China.

    PubMed

    Yang, Zhanbiao; Jin, Hongxi; Wang, Gang

    2010-05-01

    Using ecosystem attributes identified by the Society of Ecological Restoration International, we assessed three restoration projects in the loess plateau, northwestern China, including planting Larix principis-rupprechtii (LS) and Pinus tabulaeformis (PS) on shrubland, and planting L. principis-rupprechtii on open forest land (LO). The reestablishment of native species in LS and PS was poorer than LO because of the excessive stand density. Species diversity, seedling number, and seedling diversity were significantly higher in LO than in LS and PS. Soil nutrient was also significantly higher in the LO treatment. The vegetation composition, species diversity, and soil nutrient in LO, however, were more similar to these in the reference. Our results indicate that planting L. principis-rupprechtii on open forest land had accelerated the succession of the ecosystem for approximately 30 years. But the poor natural regeneration of L. principis-rupprechtii suggests that post-planting activities in LO are required after timber harvesting or the natural mortality of the L. principis-rupprechtii. Management operation such as selective thinning will be required in LS and PS to promote the true restoration of native species diversity in the future. PMID:19373438

  17. Are different facets of plant diversity well protected against climate and land cover changes? A test study in the French Alps

    PubMed Central

    Thuiller, Wilfried; Guéguen, Maya; Georges, Damien; Bonet, Richard; Chalmandrier, Loïc; Garraud, Luc; Renaud, Julien; Roquet, Cristina; Van Es, Jérémie; Zimmermann, Niklaus E.; Lavergne, Sébastien

    2014-01-01

    Climate and land cover changes are important drivers of the plant species distributions and diversity patterns in mountainous regions. Although the need for a multifaceted view of diversity based on taxonomic, functional and phylogenetic dimensions is now commonly recognized, there are no complete risk assessments concerning their expected changes. In this paper, we used a range of species distribution models in an ensemble-forecasting framework together with regional climate and land cover projections by 2080 to analyze the potential threat for more than 2,500 plant species at high resolution (2.5 km × 2.5 km) in the French Alps. We also decomposed taxonomic, functional and phylogenetic diversity facets into α and β components and analyzed their expected changes by 2080. Overall, plant species threats from climate and land cover changes in the French Alps were expected to vary depending on the species’ preferred altitudinal vegetation zone, rarity, and conservation status. Indeed, rare species and species of conservation concern were the ones projected to experience less severe change, and also the ones being the most efficiently preserved by the current network of protected areas. Conversely, the three facets of plant diversity were also projected to experience drastic spatial re-shuffling by 2080. In general, the mean α-diversity of the three facets was projected to increase to the detriment of regional β-diversity, although the latter was projected to remain high at the montane-alpine transition zones. Our results show that, due to a high-altitude distribution, the current protection network is efficient for rare species, and species predicted to migrate upward. Although our modeling framework may not capture all possible mechanisms of species range shifts, our work illustrates that a comprehensive risk assessment on an entire floristic region combined with functional and phylogenetic information can help delimitate future scenarios of biodiversity and better design its protection. PMID:25722539

  18. Diversity and Plant Growth Promoting Capacity of Endophytic Fungi Associated with Halophytic Plants from the West Coast of Korea

    PubMed Central

    Khalmuratova, Irina; Kim, Hyun; Nam, Yoon-Jong; Oh, Yoosun; Jeong, Min-Ji; Choi, Hye-Rim; You, Young-Hyun; Choo, Yeon-Sik; Lee, In-Jung; Shin, Jae-Ho

    2015-01-01

    Five halophytic plant species, Suaeda maritima, Limonium tetragonum, Suaeda australis, Phragmites australis, and Suaeda glauca Bunge, which are native to the Muan salt marsh of South Korea, were examined for fungal endophytes by sequencing the internal transcribed spacer (ITS) region containing ITS1, 5.8S rRNA, and ITS2. In total, 160 endophytic fungal strains were isolated and identified from the roots of the 5 plant species. Taxonomically, all 160 strains belonged to the phyla Ascomycota, Basidiomycota, and Zygomycota. The most dominant genus was Fusarium, followed by the genera Penicillium and Alternaria. Subsequently, using 5 statistical methods, the diversity indices of the endophytes were determined at genus level. Among these halophytic plants, P. australis was found to host the greatest diversity of endophytic fungi. Culture filtrates of endophytic fungi were treated to Waito-C rice seedlings for plant growth-promoting effects. The fungal strain Su-3-4-3 isolated from S. glauca Bunge provide the maximum plant length (20.1 cm) in comparison with wild-type Gibberella fujikuroi (19.6 cm). Consequently, chromatographic analysis of the culture filtrate of Su-3-4-3 showed the presence of physiologically active gibberellins, GA1 (0.465 ng/mL), GA3 (1.808 ng/mL) along with other physiologically inactive GA9 (0.054 ng/mL) and GA24 (0.044 ng/mL). The fungal isolate Su-3-4-3 was identified as Talaromyces pinophilus. PMID:26839496

  19. Diversity and Plant Growth Promoting Capacity of Endophytic Fungi Associated with Halophytic Plants from the West Coast of Korea.

    PubMed

    Khalmuratova, Irina; Kim, Hyun; Nam, Yoon-Jong; Oh, Yoosun; Jeong, Min-Ji; Choi, Hye-Rim; You, Young-Hyun; Choo, Yeon-Sik; Lee, In-Jung; Shin, Jae-Ho; Yoon, Hyeokjun; Kim, Jong-Guk

    2015-12-01

    Five halophytic plant species, Suaeda maritima, Limonium tetragonum, Suaeda australis, Phragmites australis, and Suaeda glauca Bunge, which are native to the Muan salt marsh of South Korea, were examined for fungal endophytes by sequencing the internal transcribed spacer (ITS) region containing ITS1, 5.8S rRNA, and ITS2. In total, 160 endophytic fungal strains were isolated and identified from the roots of the 5 plant species. Taxonomically, all 160 strains belonged to the phyla Ascomycota, Basidiomycota, and Zygomycota. The most dominant genus was Fusarium, followed by the genera Penicillium and Alternaria. Subsequently, using 5 statistical methods, the diversity indices of the endophytes were determined at genus level. Among these halophytic plants, P. australis was found to host the greatest diversity of endophytic fungi. Culture filtrates of endophytic fungi were treated to Waito-C rice seedlings for plant growth-promoting effects. The fungal strain Su-3-4-3 isolated from S. glauca Bunge provide the maximum plant length (20.1 cm) in comparison with wild-type Gibberella fujikuroi (19.6 cm). Consequently, chromatographic analysis of the culture filtrate of Su-3-4-3 showed the presence of physiologically active gibberellins, GA1 (0.465 ng/mL), GA3 (1.808 ng/mL) along with other physiologically inactive GA9 (0.054 ng/mL) and GA24 (0.044 ng/mL). The fungal isolate Su-3-4-3 was identified as Talaromyces pinophilus. PMID:26839496

  20. Diversity of fungi associated with hair roots of ericaceous plants is affected by land use.

    PubMed

    Hazard, Christina; Gosling, Paul; Mitchell, Derek T; Doohan, Fiona M; Bending, Gary D

    2014-03-01

    Culture-independent molecular studies have provided new insights into the diversity of fungi associating with ericaceous plant roots. However, there is little understanding of the distribution of these fungi across landscapes, or the effects of environmental heterogeneity on ericoid mycorrhizal (ERM) fungal diversity and distribution. Terminal-restriction fragment length polymorphism and selective sequence analyses of the internal transcribed spacer regions of rDNA were used to infer fungal diversity of bait Vaccinium macrocarpon grown in soils from nine peatland sites in Ireland, representing three different land uses (bog, rough grazing and forest plantation) and the fungal communities of field-collected Calluna vulgaris for five of these nine sites. A diverse range of potential ERM fungi were found, and the sampling approach significantly affected the diversity of the fungal community. Despite significant site groupings of the fungal communities associated with V. macrocarpon and C. vulgaris, fungal communities were significantly dissimilar between sites with different land uses. Soil nitrogen content significantly explained 52% of the variation in the V. macrocarpon fungal communities. Evidence suggests that environmental heterogeneity has a role in shaping ERM fungal community composition at the landscape scale. PMID:24741702

  1. Reliability engineering appraisal for power plants life assessment and management

    SciTech Connect

    Isreb, M.

    1998-12-31

    Reliability engineering in power plants life assessment and management aims at minimization of life synthesis cycle plant cost without compromising plant safety. Power plant reliability depends, as discussed in the present paper, on power plants life synthesis and various reliability methods such as synthesis based analysis, design, and manufacturing, operating conditions, plant reporting and recording system, plant failure analysis system, and field operational data on the same or similar power plants components. The paper presents a new approach to power plants reliability engineering appraisal. The approach, designed specifically to form part of a power plant`s overall life assessment and management, introduces a flexible mechanism for appraisal. This is done through the introduction of the Reliability Appraisal Matrix (RAM) of various reliability methods. In addition, RAM is introduced for Boiler Tubing (BT) life synthesis in relation to new, random and remnant life of BT. RAM is also introduced for BT components, namely stress rupture, water-side corrosion, fire-side corrosion, erosion, and deficiency of quality assurance leading to failure. In fact, there is a growing need in the literature to find an indicator of reliability appraisal. The indicator is introduced in the present paper as RAM. The paper recommends the standardization of RAM as an adaptable and dynamic mechanism for engineering reliability appraisal of power plant life assessment and management. Furthermore, the recommended standardization of RAM coefficients should account for different classes of power plant components, operating conditions, maintenance procedure and age.

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

    PubMed

    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 traits of dominant species and traits' dispersion in plant communities could contribute to explaining total ecosystem C storage. Thus, single- and multi-trait indices of functional composition play a crucial role in predicting C storage in sandy grasslands. PMID:26925089

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

    PubMed Central

    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 traits of dominant species and traits’ dispersion in plant communities could contribute to explaining total ecosystem C storage. Thus, single- and multi-trait indices of functional composition play a crucial role in predicting C storage in sandy grasslands. PMID:26925089

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

    NASA Astrophysics Data System (ADS)

    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 concentrations may be underestimated. Interactive effects of mesophyll conductance, nutrient limitations, CO2 concentrations and climate change will be discussed in the context of new parameterizations enabled with our intensive measurements in Panama.

  5. Straight Talk about Assessment and Diversity: What Do We Know?

    ERIC Educational Resources Information Center

    Braden, Jeffrey P.

    1999-01-01

    Article examines whether assessments create, or merely reflect, between-group differences in cognitive abilities and achievement. It explores why school psychologists resist the conclusion that group differences are real, and considers the types of research and knowledge needed to move the discussion of assessment bias past its current…

  6. Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow

    PubMed Central

    Li, Wei; Cheng, Ji-Min; Yu, Kai-Liang; Epstein, Howard E.; Guo, Liang; Jing, Guang-Hua; Zhao, Jie; Du, Guo-Zhen

    2015-01-01

    Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alpine meadow community on the Tibetan Plateau. To this purpose, three community-weighted mean trait values (specific leaf area, SLA; mature plant height, MPH; and seed size, SS) for 30 common species in each fertilization level were determined; three components of functional diversity (functional richness, FRic; functional evenness, FEve; and Rao’s index of quadratic entropy, FRao) were quantified. Our results showed that: (i) species diversity sharply decreased, but functional diversity remained stable with fertilization; (ii) community-weighted mean traits (SLA and MPH) had a significant increase along the fertilization level; (iii) aboveground biomass was not correlated with functional diversity, but it was significantly correlated with species diversity and MPH. Our results suggest that decreases in species diversity due to fertilization do not result in corresponding changes in functional diversity. Functional identity of species may be more important than functional diversity in influencing aboveground productivity in this alpine meadow community, and our results also support the mass ratio hypothesis; that is, the traits of the dominant species influenced the community biomass production. PMID:26295345

  7. Genomic and genetic analyses of diversity and plant interactions of Pseudomonas fluorescens

    PubMed Central

    Silby, Mark W; Cerdeño-Tárraga, Ana M; Vernikos, Georgios S; Giddens, Stephen R; Jackson, Robert W; Preston, Gail M; Zhang, Xue-Xian; Moon, Christina D; Gehrig, Stefanie M; Godfrey, Scott AC; Knight, Christopher G; Malone, Jacob G; Robinson, Zena; Spiers, Andrew J; Harris, Simon; Challis, Gregory L; Yaxley, Alice M; Harris, David; Seeger, Kathy; Murphy, Lee; Rutter, Simon; Squares, Rob; Quail, Michael A; Saunders, Elizabeth; Mavromatis, Konstantinos; Brettin, Thomas S; Bentley, Stephen D; Hothersall, Joanne; Stephens, Elton; Thomas, Christopher M; Parkhill, Julian; Levy, Stuart B; Rainey, Paul B; Thomson, Nicholas R

    2009-01-01

    Background Pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. The genome sequences of strains SBW25 and Pf0-1 were determined and compared to each other and with P. fluorescens Pf-5. A functional genomic in vivo expression technology (IVET) screen provided insight into genes used by P. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity within this species. Results Comparisons of three P. fluorescens genomes (SBW25, Pf0-1, Pf-5) revealed considerable divergence: 61% of genes are shared, the majority located near the replication origin. Phylogenetic and average amino acid identity analyses showed a low overall relationship. A functional screen of SBW25 defined 125 plant-induced genes including a range of functions specific to the plant environment. Orthologues of 83 of these exist in Pf0-1 and Pf-5, with 73 shared by both strains. The P. fluorescens genomes carry numerous complex repetitive DNA sequences, some resembling Miniature Inverted-repeat Transposable Elements (MITEs). In SBW25, repeat density and distribution revealed 'repeat deserts' lacking repeats, covering approximately 40% of the genome. Conclusions P. fluorescens genomes are highly diverse. Strain-specific regions around the replication terminus suggest genome compartmentalization. The genomic heterogeneity among the three strains is reminiscent of a species complex rather than a single species. That 42% of plant-inducible genes were not shared by all strains reinforces this conclusion and shows that ecological success requires specialized and core functions. The diversity also indicates the significant size of genetic information within the Pseudomonas pan genome. PMID:19432983

  8. Plant-Wide Assessment Report for Shaw Industries, Plant #78; Aiken, SC

    SciTech Connect

    Michael Brown PE, CEM; Matt Soderlund; Bill Meffert PE; Paolo Baldisserotto; Jerry Zolkowski PE, CEM

    2006-04-10

    A plant-wide energy assessment sponsored by the U.S. Department of Energy was conducted at Shaw Industries Group, plant #78 in Aiken, SC. The assessment team consisted of Georgia Tech faculty from the Energy & Environmental Management Center and Shaw personnel from plant #78 and the corporate energy group. The purpose of this assessment was to uncover as many opportunities for saving energy usage and costs using techniques that have been established as best practices in the energy engineering field. In addition, these findings are to be shared with similar plants in Shaw Industries Group to multiply the lessons learned. The findings from this assessment are included in this report.

  9. How Do Earthworms, Soil Texture and Plant Composition Affect Infiltration along an Experimental Plant Diversity Gradient in Grassland?

    PubMed Central

    Fischer, Christine; Roscher, Christiane; Jensen, Britta; Eisenhauer, Nico; Baade, Jussi; Attinger, Sabine; Scheu, Stefan; Weisser, Wolfgang W.; Schumacher, Jens; Hildebrandt, Anke

    2014-01-01

    Background Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied. Methodology/Principal Findings We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species) and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs). In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i) direct, probably by modifying the pore spectrum and (ii) indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms. Conclusions/Significance Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications. PMID:24918943

  10. Measuring plant diversity in the tall threetip sagebrush steppe: influence of previous grazing management practices.

    PubMed

    Seefeldt, Steven S; McCoy, Scott D

    2003-08-01

    In July 2000, a 490-ha wildfire burned a portion of a long-term grazing study that had been established in 1924 at the US Sheep Experiment Station north of Dubois, Idaho, USA. Earlier vegetation measurements in this tall threetip sagebrush (Artemisia tripartita spp. tripartita) bunchgrass plant community documented significant changes in vegetation due to grazing and the timing of grazing by sheep. A study was initiated in May 2001 using 12 multiscale modified Whittaker plots to determine the consequences of previous grazing practices on postfire vegetation composition. Because there was only one wildfire and it did not burn all of the original plots, the treatments are not replicated in time or space. We reduce the potential effects of psuedoreplication by confining our discussion to the sample area only. There were a total of 84 species in the sampled areas with 69 in the spring-grazed area and 70 each in the fall- and ungrazed areas. Vegetation within plots was equally rich and even with similar numbers of abundant species. The spring-grazed plots, however, had half as much plant cover as the fall- and ungrazed plots and the spring-grazed plots had the largest proportion of plant cover composed of introduced (27%) and annual (34%) plants. The fall-grazed plots had the highest proportion of native perennial grasses (43%) and the lowest proportion of native annual forbs (1%). The ungrazed plots had the lowest proportion of introduced plants (4%) and the highest proportion of native perennial forbs (66%). The vegetation of spring-grazed plots is in a degraded condition for the environment and further degradation may continue, with or without continued grazing or some other disturbance. If ecosystem condition was based solely on plant diversity and only a count of species numbers was used to determine plant diversity, this research would have falsely concluded that grazing and timing of grazing did not impact the condition of the ecosystem. PMID:14753648

  11. Assessment of genetic diversity among selected raspberry cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic markers, Random Amplification of Polymorphic DNA (RAPD), were developed for screening raspberry for cold/heat tolerance. Growing raspberries in southern United States is a challenging task as they are high chill-loving plants. Cultivation of raspberry in Florida is significantly hampered du...

  12. Assessing diversity and phytoremediation potential of seagrass in tropical region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seagrass ecosystem is one of the most important resources in the coastal areas. Seagrasses support and provide habitats for many coastal organisms in tropical region. Seagrasses are specialized marine flowering plants that have adapted to the nearshore environment with heterogeneous landscape struct...

  13. The evolution of plant secretory structures and emergence of terpenoid chemical diversity.

    PubMed

    Lange, Bernd Markus

    2015-01-01

    Secretory structures in terrestrial plants appear to have first emerged as intracellular oil bodies in liverworts. In vascular plants, internal secretory structures, such as resin ducts and laticifers, are usually found in conjunction with vascular bundles, whereas subepidermal secretory cavities and epidermal glandular trichomes generally have more complex tissue distribution patterns. The primary function of plant secretory structures is related to defense responses, both constitutive and induced, against herbivores and pathogens. The ability to sequester secondary (or specialized) metabolites and defense proteins in secretory structures was a critical adaptation that shaped plant-herbivore and plant-pathogen interactions. Although this review places particular emphasis on describing the evolution of pathways leading to terpenoids, it also assesses the emergence of other metabolite classes to outline the metabolic capabilities of different plant lineages. PMID:25621517

  14. Genetic Diversity and Spoilage Potentials among Pseudomonas spp. Isolated from Fluid Milk Products and Dairy Processing Plants

    PubMed Central

    Dogan, Belgin; Boor, Kathryn J.

    2003-01-01

    Degradation of milk components through various enzymatic activities associated with the contamination of dairy products by Pseudomonas spp. can reduce the shelf life of processed milk. Reliable methods for differentiating among Pseudomonas spp. strains are necessary to identify and eliminate specific sources of bacterial contamination from dairy processing systems. To that end, we assessed the genetic diversity and dairy product spoilage potentials among a total of 338 Pseudomonas spp. isolates from raw and pasteurized milk and from environmental samples collected from four dairy processing plants. The majority of isolates were identified as P. fluorescens and P. putida by API 20 NE. A total of 42 different ribotype patterns were identified among a subset of 81 isolates. The presence of many different ribotypes within this collection indicates high genetic diversity among the isolates and suggests multiple origins of contamination within the processing plant and in dairy products. The extracellular enzyme activity patterns among Pseudomonas isolates appeared to be associated with ribotypes. Isolates with the same ribotype frequently had the same extracellular protease, lecithinase, and lipase activities. For example, isolates grouped in ribotype 55-S-6 had the highest extracellular protease activity, while those in ribotypes 50-S-8 and 72-S-3 had the highest extracellular lipase activities. We conclude that ribotyping provides a reliable method for differentiating Pseudomonas strains with dairy food spoilage potential. PMID:12513987

  15. Genetic Structure, Diversity and Long Term Viability of a Medicinal Plant, Nothapodytes nimmoniana Graham. (Icacinaceae), in Protected and Non-Protected Areas in the Western Ghats Biodiversity Hotspot

    PubMed Central

    Shivaprakash, K. Nagaraju; Ramesha, B. Thimmappa; Uma Shaanker, Ramanan; Dayanandan, Selvadurai; Ravikanth, Gudasalamani

    2014-01-01

    Background and Question The harvesting of medicinal plants from wild sources is escalating in many parts of the world, compromising the long-term survival of natural populations of medicinally important plants and sustainability of sources of raw material to meet pharmaceutical industry needs. Although protected areas are considered to play a central role in conservation of plant genetic resources, the effectiveness of protected areas for maintaining medicinal plant populations subject to intense harvesting pressure remain largely unknown. We conducted genetic and demographic studies of Nothapodytes nimmoniana Graham, one of the extensively harvested medicinal plant species in the Western Ghats biodiversity hotspot, India to assess the effectiveness of protected areas in long-term maintenance of economically important plant species. Methodology/Principal Findings The analysis of adults and seedlings of N. nimmoniana in four protected and four non-protected areas using 7 nuclear microsatellite loci revealed that populations that are distributed within protected areas are subject to lower levels of harvesting and maintain higher genetic diversity (He?=?0.816, Ho?=?0.607, A?=?18.857) than populations in adjoining non-protected areas (He?=?0.781, Ho?=?0.511, A?=?15.571). Furthermore, seedlings in protected areas had significantly higher observed heterozygosity (Ho?=?0.630) and private alleles as compared to seedlings in adjoining non-protected areas (Ho?=?0.426). Most populations revealed signatures of recent genetic bottleneck. The prediction of long-term maintenance of genetic diversity using BOTTLESIM indicated that current population sizes of the species are not sufficient to maintain 90% of present genetic diversity for next 100 years. Conclusions/Significance Overall, these results highlight the need for establishing more protected areas encompassing a large number of adult plants in the Western Ghats to conserve genetic diversity of economically and medicinally important plant species. PMID:25493426

  16. Assessing the Unseen Bacterial Diversity in Microbial Communities

    PubMed Central

    Caro-Quintero, Alejandro; Ochman, Howard

    2015-01-01

    For both historical and technical reasons, 16S ribosomal RNA has been the most common molecular marker used to analyze the contents of microbial communities. However, its slow rate of evolution hinders the resolution of closely related bacteria—individual 16S-phylotypes, particularly when clustered at 97% sequence identity, conceal vast amounts of species- and strain-level variation. Protein-coding genes, which evolve more quickly, are useful for differentiating among more recently diverged lineages, but their application is complicated by difficulties in designing low-redundancy primers that amplify homologous regions from distantly related taxa. Given the now-common practice of multiplexing hundreds of samples, adopting new genes usually entails the synthesis of large sets of barcoded primers. To circumvent problems associated with use of protein-coding genes to survey microbial communities, we develop an approach—termed phyloTAGs—that offers an automatic solution for primer design and can be easily adapted to target different taxonomic groups and/or different protein-coding regions. We applied this method to analyze diversity within the gorilla gut microbiome and recovered hundreds of strains that went undetected after deep-sequencing of 16S rDNA amplicons. PhyloTAGs provides a powerful way to recover the fine-level diversity within microbial communities and to study stability and dynamics of bacterial populations. PMID:26615218

  17. Assessing the Unseen Bacterial Diversity in Microbial Communities.

    PubMed

    Caro-Quintero, Alejandro; Ochman, Howard

    2015-12-01

    For both historical and technical reasons, 16S ribosomal RNA has been the most common molecular marker used to analyze the contents of microbial communities. However, its slow rate of evolution hinders the resolution of closely related bacteria-individual 16S-phylotypes, particularly when clustered at 97% sequence identity, conceal vast amounts of species- and strain-level variation. Protein-coding genes, which evolve more quickly, are useful for differentiating among more recently diverged lineages, but their application is complicated by difficulties in designing low-redundancy primers that amplify homologous regions from distantly related taxa. Given the now-common practice of multiplexing hundreds of samples, adopting new genes usually entails the synthesis of large sets of barcoded primers. To circumvent problems associated with use of protein-coding genes to survey microbial communities, we develop an approach-termed phyloTAGs-that offers an automatic solution for primer design and can be easily adapted to target different taxonomic groups and/or different protein-coding regions. We applied this method to analyze diversity within the gorilla gut microbiome and recovered hundreds of strains that went undetected after deep-sequencing of 16S rDNA amplicons. PhyloTAGs provides a powerful way to recover the fine-level diversity within microbial communities and to study stability and dynamics of bacterial populations. PMID:26615218

  18. Biochemical survey of the polar head of plant glycosylinositolphosphoceramides unravels broad diversity.

    PubMed

    Cacas, Jean-Luc; Buré, Corinne; Furt, Fabienne; Maalouf, Jean-Paul; Badoc, Alain; Cluzet, Stéphanie; Schmitter, Jean-Marie; Antajan, Elvire; Mongrand, Sébastien

    2013-12-01

    Although Glycosyl-Inositol-Phospho-Ceramides (GIPCs) are the main sphingolipids of plant tissues, they remain poorly characterized in term of structures. This lack of information, notably with regard to polar heads, currently hampers the understanding of GIPC functions in biological systems. This situation prompted us to undertake a large scale-analysis of plant GIPCs: 23 plant species chosen in various phylogenetic groups were surveyed for their total GIPC content. GIPCs were extracted and their polar heads were characterized by negative ion MALDI and ESI mass spectrometry. Our data shed light on an unexpected broad diversity of GIPC distributions within Plantae, and the occurrence of yet-unreported GIPC structures in green and red algae. In monocots, GIPCs with three saccharides were apparently found to be major, whereas a series with two saccharides was dominant in Eudicots within a few notable exceptions. In plant cell cultures, GIPC polar heads appeared to bear a higher number of glycan units than in the tissue from which they originate. Perspectives are discussed in term of GIPC metabolism diversity and function of these lipids. PMID:23993446

  19. Learning to Assess Science in Linguistically Diverse Classrooms: Tracking Growth in Secondary Science Preservice Teachers' Assessment Expertise

    ERIC Educational Resources Information Center

    Lyon, Edward G.

    2013-01-01

    Although studies have documented teachers' growth in assessing science resulting from professional development or science methods courses, little attention has been given to growth while being prepared to assess a linguistically diverse student population. In this study, the growth of 11 secondary science preservice teachers is documented by…

  20. Quality assessment of plant transpiration water

    NASA Technical Reports Server (NTRS)

    Macler, Bruce A.; Janik, Daniel S.; Benson, Brian L.

    1990-01-01

    It has been proposed to use plants as elements of biologically-based life support systems for long-term space missions. Three roles have been brought forth for plants in this application: recycling of water, regeneration of air and production of food. This report discusses recycling of water and presents data from investigations of plant transpiration water quality. Aqueous nutrient solution was applied to several plant species and transpired water collected. The findings indicated that this water typically contained 0.3-6 ppm of total organic carbon, which meets hygiene water standards for NASA's space applications. It suggests that this method could be developed to achieve potable water standards.

  1. Diversity and productivity of plant communities across the Inland Northwest, USA.

    PubMed

    Jennings, Michael D; Williams, John W; Stromberg, Mark R

    2005-05-01

    No definitive explanation for the form of the relationship between species diversity and ecosystem productivity exists nor is there agreement on the mechanisms linking diversity and productivity across scales. Here, we examine changes in the form of the diversity-productivity relationship within and across the plant communities at three observational scales: plots, alliances, and physiognomic vegetation types (PVTs). Vascular plant richness data are from 4,760 20 m2 vegetation field plots. Productivity estimates in grams carbon per square meter are from annual net primary productivity (ANPP) models. Analyses with generalized linear models confirm scale dependence in the species diversity-productivity relationship. At the plot focus, the observed diversity-productivity relationship was weak. When plot data were aggregated to a focus of vegetation alliances, a hump-shaped relationship was observed. Species turnover among plots cannot explain the observed hump-shaped relationship at the alliance focus because we used mean plot richness across plots as our index of species richness for alliances and PVTs. The sorting of alliances along the productivity gradient appears to follow regional patterns of moisture availability, with alliances that occupy dry environments occurring within the increasing phase of the hump-shaped pattern, alliances that occupy mesic to hydric environments occurring near the top or in the decreasing phase of the curve, and alliances that occupy the wettest environments having the fewest species and the highest ANPP. This pattern is consistent with the intermediate productivity theory but appears to be inconsistent with the predictions of water-energy theory. PMID:15909130

  2. Plant species diversity and composition of experimental grasslands affect genetic differentiation of Lolium perenne populations.

    PubMed

    Nestmann, S; Sretenovic Rajicic, T; Dehmer, K J; Fischer, M; Schumacher, J; Roscher, C

    2011-05-01

    Contrasting hypotheses exist about the relationship between plant species diversity and genetic diversity. However, experimental data of species diversity effects on genetic differentiation among populations are lacking. To address this, Lolium perenne was sown with an equal number of seeds in 78 experimental grasslands (Jena Experiment) varying in species richness (1, 2, 4, 8 to 16) and functional group richness and composition (1-4; grasses, legumes, small herbs, tall herbs). Population sizes were determined 4years after sowing, and single-nucleotide polymorphism (SNP) DNA markers based on bulk samples of up to 100 individuals per population were applied. Genetic distances between the field populations and the initially sown seed population increased with sown species richness. The degree of genetic differentiation from the original seed population was largely explained by actual population sizes, which suggests that genetic drift was the main driver of differentiation. Weak relationships among relative allele frequencies and species diversity or actual population sizes, and a positive correlation between actual population sizes and expected heterozygosity also supported the role of genetic drift. Functional composition had additional effects on genetic differentiation of L. perenne populations, indicating a selection because of genotype-specific interactions with other species. Our study supports that genetic diversity is likely to be lower in plant communities with a higher number of interspecific competitors. Negative effects of species richness on population sizes may increase the probability of genetic drift, and selection because of genotype-specific interactions depending on species and genotypic community composition may modulate this relationship. PMID:21352387

  3. Variations in AOC and microbial diversity in an advanced water treatment plant

    NASA Astrophysics Data System (ADS)

    Yang, B. M.; Liu, J. K.; Chien, C. C.; Surampalli, R. Y.; Kao, C. M.

    2011-10-01

    SummaryThe objective of this study was to evaluate the variations in assimilable organic carbon (AOC) and microbial diversities in an advanced water treatment plant. The efficiency of biofiltration on AOC removal using anthracite and granular activated carbon (GAC) as the media was also evaluated through a pilot-scale column experiment. Effects of hydrological factors (seasonal effects and river flow) on AOC concentrations in raw water samples and hydraulic retention time (HRT) of biofiltration on AOC treatment were also evaluated. Results show that AOC concentrations in raw water and clear water of the plant were about 138 and 27 ?g acetate-C/L, respectively. Higher AOC concentrations were observed in wet seasons probably due to the resuspension of organic-contained sediments and discharges of non-point source (NPS) pollutants from the upper catchment. This reveals that seasonal effect played an important role in the variations in influent AOC concentrations. Approximately 82% and 70% of AOC removal efficiencies were observed in GAC and anthracite columns, respectively. Results from column experiment reveal that the applied treatment processes in the plant and biofiltration system were able to remove AOC effectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic (SEM) images. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal significant decrease in microbial diversities after the ozonation process. Higher HRT caused higher microbial contact time, and thus, more microbial colonies and higher microbial diversity were observed in the latter part of the biofilters. Some of the dominant microbial species in the biofiltration columns belonged to the beta- proteobacterium, which might contribute to the AOC degradation. Results of this study provide us insight into the variations in AOC and microbial diversity in the advanced water treatment processes.

  4. [Correlation between aquatic plant diversity and water environment in the typical sites of Hangzhou section of the Beijing-Hangzhou Grand Canal].

    PubMed

    Lu, Yin; Xu, Xiao-Lu; Zhang, De-Yong; Wang, Li; Zhu, Xu-Ni; Feng, Feng; Zhou, Qiao-Jun; Xie, Peng

    2014-05-01

    Community characteristics of aquatic plant are important indicators for water quality. In order to understand the distribution characteristics of aquatic plants in aquatic ecosystem of the Beijing-Hangzhou Grand Canal ( Hangzhou section) , and to analyze the relationship between water quality and plant community, an investigation of the aquatic plants in five typical sites was made in this study. Species composition, biological diversity, quantity distribution and dominant species of aquatic plants in five sites were studied for ecological changes. Physicochemical factors such as temperature, pH value, transparency, dissolved oxygen and main elements of living were also analyzed. Based on the results, the distribution of phytoplankton diversity and environment factor correlations by multivariate statistical analysis were discussed. The trophic levels of these sites were assessed by using related biological standards. Results indicated that the diversity of aquatic plant mainly depends on the diversity of phytoplankton in the typical sites of the Beijing-Hangzhou Grand Canal. We observed and identified 35 genus algae, including advantage community of Hyalodiscus Ehrenberg and Melosira Agardh, which belonged to Bacillariophyta. According to the impact on the phytoplankton diversity and distribution, factors such as dissolved oxygen, transparency, water temperature, etc. had an obvious influence on the distribution of phytoplankton in the existing 6 environmental factors, while the influence of pH value was the highest. In terms of water quality eutrophication, site Tangxi Bridge and Maiyu Bridge showed a relatively lighter pollution, while site Yiqiao Bridge, Gujia Bridge and Gongchen Bridge showed a higher pollution, and the pollution of site Yiqiao Bridge was the most serious. PMID:25055657

  5. Diverse plant and animal genetic records from Holocene and Pleistocene sediments.

    PubMed

    Willerslev, Eske; Hansen, Anders J; Binladen, Jonas; Brand, Tina B; Gilbert, M Thomas P; Shapiro, Beth; Bunce, Michael; Wiuf, Carsten; Gilichinsky, David A; Cooper, Alan

    2003-05-01

    Genetic analyses of permafrost and temperate sediments reveal that plant and animal DNA may be preserved for long periods, even in the absence of obvious macrofossils. In Siberia, five permafrost cores ranging from 400,000 to 10,000 years old contained at least 19 different plant taxa, including the oldest authenticated ancient DNA sequences known, and megafaunal sequences including mammoth, bison, and horse. The genetic data record a number of dramatic changes in the taxonomic diversity and composition of Beringian vegetation and fauna. Temperate cave sediments in New Zealand also yielded DNA sequences of extinct biota, including two species of ratite moa, and 29 plant taxa characteristic of the prehuman environment. Therefore, many sedimentary deposits may contain unique, and widespread, genetic records of paleoenvironments. PMID:12702808

  6. Chemical diversity of microbial volatiles and their potential for plant growth and productivity

    PubMed Central

    Kanchiswamy, Chidananda Nagamangala; Malnoy, Mickael; Maffei, Massimo E.

    2015-01-01

    Microbial volatile organic compounds (MVOCs) are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity, and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides, and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs by describing microbial–plants and microbial–microbial interactions. Furthermore, we discuss MVOCs role in inducing phenotypic plant responses and their potential physiological effects on crops. Finally, we analyze potential and actual limitations for MVOC use and deployment in field conditions as a sustainable strategy for improving productivity and reducing pesticide use. PMID:25821453

  7. Chemical diversity of microbial volatiles and their potential for plant growth and productivity.

    PubMed

    Kanchiswamy, Chidananda Nagamangala; Malnoy, Mickael; Maffei, Massimo E

    2015-01-01

    Microbial volatile organic compounds (MVOCs) are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity, and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides, and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs by describing microbial-plants and microbial-microbial interactions. Furthermore, we discuss MVOCs role in inducing phenotypic plant responses and their potential physiological effects on crops. Finally, we analyze potential and actual limitations for MVOC use and deployment in field conditions as a sustainable strategy for improving productivity and reducing pesticide use. PMID:25821453

  8. Discovery of structurally diverse and bioactive compounds from plant resources in China

    PubMed Central

    Yang, Sheng-ping; Yue, Jian-min

    2012-01-01

    This review describes the major discoveries of structurally diverse and/or biologically significant compounds from plant resources in China, mainly from the traditional Chinese medicines (TCMs) since the establishment of our research group in 1999. In the past decade, a large array of biologically significant and novel structures has been identified from plant resources (or TCM) in our laboratory. The structural modification of several biologically important compounds led to more than 400 derivatives, some of which exhibited significantly improved activities and provided opportunities to elucidate the structure-activity relationship of the related compound class. These findings are important for drug discovery and help us understand the biological basis for the traditional applications of these plants in TCM. PMID:22941284

  9. Disentangling the roles of plant diversity and precipitation in structuring microbial community composition and function in a tropical rain forest

    NASA Astrophysics Data System (ADS)

    McGuire, Krista; Treseder, Kathleen; Fierer, Noah; Turner, Benjamin

    2010-05-01

    Shifting frequency and intensity of precipitation events is expected to impact soil fungi through a variety of complex feedbacks, although the general patterns and mechanisms are not fully understood. Precipitation and plant diversity often covary, and disentangling the relative contribution of each is important for predicting changes in global C and N fluxes. In order to test the relative contributions of plant diversity and precipitation in shaping fungal community structure and function, soil samples (0-10cm) from six established 1-ha plots across a natural precipitation gradient on the isthmus of Panama were collected. These plots co-vary in mean annual precipitation and plant diversity. Fungal DNA was sequenced using general fungal primers for the 18S region and 454 pyrosequencing. We found that total fungal taxa significantly increased with increasing mean annual precipitation, but not with plant diversity. Activity for some extracellular enzymes increased, whereas as others decreased with mean annual precipitation, indicating that the effect of shifting precipitation on nutrient transformations may be process-specific. To directly test for effects of plant species richness on fungal diversity and function, we experimentally re-created litter diversity gradients in nylon, 2 mm screen litter bags with 1, 25, and 50 species of plant leaf litter. After six months, we found a significant effect of plant litter diversity on decomposition rate, but only after the increase from one to 25 species of leaf litter. Total fungal taxa as determined by 454 sequencing and extracellular enzyme activity did not track plant species richness, suggesting that precipitation may be a more important factor than plant diversity in structuring soil fungi in tropical rain forests.

  10. Reasons for Seasons Assessment Outcomes For Diverse Students

    NASA Astrophysics Data System (ADS)

    Faubert, R. M.; Pyke, C.; Lynch, S.; Ochsendorf, R.

    2003-12-01

    National systemic reform initiatives point to the need for a more focused science curriculum and better curriculum materials for teachers to use (aligned with science standards, instructional methods, and assessment/accountability measures). Assessment developers face the difficult task of identifying and revealing what students actually know that is relevant to curricular goals. The SCALE-uP Project at the George Washington University has attempted to create such assessments using an adapted rigorous set of criteria based on an assessment item analysis procedure developed by the American Association for the Advancement of Science Project 2061. The procedure evaluates an assessment task's potential to reveal whether students have attained "a well-defined component of knowledge or acquired a particular skill" (Stern and Ahlgren, 2002). To determine students' scientific understanding of what causes the Earth's seasons, the SCALE-uP Project focuses on a single Benchmark from Benchmarks for Science Literacy (AAAS, 1993) that include both empirical observations and theoretical statements related to the target concept (Earth's seasons). In the conceptual model guiding our assessment development, we believe the target concept, articulated through the Benchmark (4B,6-8, #4), represents a single coherent knowledge structure and mental model stored in memory that students can recall or access when needed to explain relevant phenomena or solve tasks. Therefore, students that possess the concept of the Earth's seasons would be expected to respond to phenomena related to seasons with consistent and coherent responses to probes and representations related to the Benchmark idea. The instrument development procedure compares assessment outcomes (cognitive model/framework) of about 30 general 7th grade students with little previous classroom exposure to learning about the seasons, to high achieving 8th graders who have studied the seasons, and to introductory astronomy college students, who presumably understand the reasons for Earth's seasons. In this paper, we report on the results of the initial administrations of the instrument for these three groups.

  11. High plant species diversity indirectly mitigates CO 2- and N-induced effects on grasshopper growth

    NASA Astrophysics Data System (ADS)

    Strengbom, Joachim; Reich, Peter B.; Ritchie, Mark E.

    2008-09-01

    We examined how elevated atmospheric [CO 2] and higher rate of nitrogen (N) input may influence grasshopper growth by changing food plant quality and how such effects may be modified by species diversity of the plant community. We reared grasshopper nymphs ( Melanoplus femurrubrum) on Poa pratensis from field-grown monocultures or polycultures (16 species) that were subjected to either ambient or elevated levels of CO 2 and N. Grasshopper growth rate was higher on P. pratensis leaves grown in monocultures than in polycultures, higher on P. pratensis grown under elevated than under ambient [CO 2], and higher on P. pratensis grown under elevated than under ambient [N]. The higher growth rate observed on P. pratensis exposed to elevated [CO 2] was, however, less pronounced for polyculture- than monoculture-grown P. pratensis. Growth rate of the grasshoppers was positively correlated with leaf [N], [C], and concentration of soluble carbohydrates + lipids. Concentration of non-structural carbohydrates + lipids was higher in leaves grown under elevated than under ambient [CO 2], and the difference between P. pratensis grown under ambient and elevated [CO 2] was greater for monoculture- than polyculture-grown P. pratensis. In addition, leaf N concentration was higher in P. pratensis grown in monocultures than in polycultures, suggesting that plant species richness, indirectly, may influence insect performance by changed nutritional value of the plants. Because we found interactive effects between all factors included ([CO 2], [N], and plant species diversity), our results suggest that these parameters may influence plant-insect interactions in a complex way that is not predictable from the sum of single factor manipulations.

  12. Congruence and Diversity of Butterfly-Host Plant Associations at Higher Taxonomic Levels

    PubMed Central

    Ferrer-Paris, José R.; Sánchez-Mercado, Ada; Viloria, Ángel L.; Donaldson, John

    2013-01-01

    We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages. PMID:23717448

  13. Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area.

    PubMed

    Hu, Jinxiang; Yang, Hui; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-01-01

    Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area. PMID:26902649

  14. Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area

    PubMed Central

    Hu, Jinxiang; Yang, Hui; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-01-01

    Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area. PMID:26902649

  15. Elevated CO2 and plant species diversity interact to slow root decomposition

    SciTech Connect

    De Graaff, Marie-Anne; Schadt, Christopher Warren; Rula, Kelly L; Six, Johan W U A; Schweitzer, Jennifer A; Classen, Aimee T

    2011-01-01

    Changes in plant species diversity can result in synergistic increases in decomposition rates, while elevated atmospheric CO2 can slow the decomposition rates; yet it remains unclear how diversity and changes in atmospheric CO2 may interact to alter root decomposition. To investigate how elevated CO2 interacts with changes in root-litter diversity to alter decomposition rates, we conducted a 120-day laboratory incubation. Roots from three species (Trifolium repens, Lespedeza cuneata, and Festuca pratense) grown under ambient or elevated CO2 were incubated individually or in combination in soils that were exposed to ambient or elevated CO2 for five years. Our experiment resulted in two main findings: (1) Roots from T. repens and L. cuneata, both nitrogen (N) fixers, grown under elevated CO2 treatments had significantly slower decomposition rates than similar roots grown under ambient CO2 treatments; but the decomposition rate of F. pratense roots (a non-N-fixing species) was similar regardless of CO2 treatment. (2) Roots of the three species grown under ambient CO2 and decomposed in combination with each other had faster decomposition rates than when they were decomposed as single species. However, roots of the three species grown under elevated CO2 had similar decomposition rates when they were incubated alone or in combination with other species. These data suggest that if elevated CO2 reduces the root decomposition rate of even a few species in the community, it may slow root decomposition of the entire plant community.

  16. Beta Diversity of Plant-Pollinator Networks and the Spatial Turnover of Pairwise Interactions

    PubMed Central

    Carstensen, Daniel W.; Sabatino, Malena; Trøjelsgaard, Kristian; Morellato, Leonor Patricia C.

    2014-01-01

    Interactions between species form complex networks that vary across space and time. Even without spatial or temporal constraints mutualistic pairwise interactions may vary, or rewire, across space but this variability is not well understood. Here, we quantify the beta diversity of species and interactions and test factors influencing the probability of turnover of pairwise interactions across space. We ask: 1) whether beta diversity of plants, pollinators, and interactions follow a similar trend across space, and 2) which interaction properties and site characteristics are related to the probability of turnover of pairwise interactions. Geographical distance was positively correlated with plant and interaction beta diversity. We find that locally frequent interactions are more consistent across space and that local flower abundance is important for the realization of pairwise interactions. While the identity of pairwise interactions is highly variable across space, some species-pairs form interactions that are locally frequent and spatially consistent. Such interactions represent cornerstones of interacting communities and deserve special attention from ecologists and conservation planners alike. PMID:25384058

  17. KIPS: An Evidence-Based Tool for Assessing Parenting Strengths and Needs in Diverse Families

    ERIC Educational Resources Information Center

    Comfort, Marilee; Gordon, Philip R.; Naples, Denise

    2011-01-01

    The movement toward evidence-based practices has stimulated greater interest in assessing parenting outcomes. The purpose of these studies was to further validate the Keys to Interactive Parenting Scale (KIPS), a structured observational assessment of parenting quality, with 397 diverse families. Factor analysis demonstrated that the 12 KIPS items…

  18. Water treatment plants assessment at Talkha power plant.

    PubMed

    El-Sebaie, Olfat D; Abd El-Kerim, Ghazy E; Ramadan, Mohamed H; Abd El-Atey, Magda M; Taha, Sahr Ahmed

    2002-01-01

    Talkha power plant is the only power plant located in El-Mansoura. It generates electricity using two different methods by steam turbine and gas turbine. Both plants drew water from River Nile (208 m3 /h). The Nile raw water passes through different treatment processes to be suitable for drinking and operational uses. At Talkha power plant, there are two purification plants used for drinking water supply (100 m3/h) and for water demineralization supply (108 m3/h). This study aimed at studying the efficiency of the water purification plants. For drinking water purification plant, the annual River Nile water characterized by slightly alkaline pH (7.4-8), high annual mean values of turbidity (10.06 NTU), Standard Plate Count (SPC) (313.3 CFU/1 ml), total coliform (2717/100 ml), fecal coliform (0-2400/100 ml), and total algae (3 x 10(4) org/I). The dominant group of algae all over the study period was green algae. The blue green algae was abundant in Summer and Autumn seasons. The pH range, and the annual mean values of turbidity, TDS, total hardness, sulfates, chlorides, nitrates, nitrites, fluoride, and residual chlorine for purified water were in compliance with Egyptian drinking water standards. All the SPC recorded values with an annual mean value of 10.13 CFU/1 ml indicated that chlorine dose and contact time were not enough to kill the bacteria. However, they were in compliance with Egyptian decree (should not exceed 50 CFU/1 ml). Although the removal efficiency of the plant for total coliform and blue green algae was high (98.5% and 99.2%, respectively), the limits of the obtained results with an annual mean values of 40/100 ml and 15.6 org/l were not in compliance with the Egyptian decree (should be free from total coliform, fecal coliform and blue green algae). For water demineralization treatment plant, the raw water was characterized by slightly alkaline pH. The annual mean values of conductivity, turbidity, and TDS were 354.6 microS/cm, 10.84 NTU, and 214.6 mg/I, respectively. There was an increase in the results of conductivity, turbidity, total hardness, and TDS in carbon filter effluent which was attributed to the desorption of adsorbed ions on the carbon media. The removal efficiencies of turbidity, total hardness, and TDS indicated the high efficiency of the cationic filter. The annual removal efficiencies of conductivity, turbidity, chloride, and TDS proved the efficiency of the anionic filter for removing the dissolved and suspended ions. All of the recorded values of the pH, conductivity, turbidity, chlorides, hardness, and TDS of the mixed bed effluent indicated that the water at this stage was of high quality for boiler feed. The study recommended adjustment of coagulant and residual chlorine doses as well as contact time, and continuous monitoring and maintenance of the different units. PMID:17216967

  19. Testing successional hypotheses of stability, heterogeneity, and diversity in pitcher-plant inquiline communities.

    PubMed

    Miller, Thomas E; terHorst, Casey P

    2012-09-01

    Succession is a foundation concept in ecology that describes changes in species composition through time, yet many successional patterns have not been thoroughly investigated. We highlight three hypotheses about succession that are often not clearly stated or tested: (1) individual communities become more stable over time, (2) replicate communities become more similar over time, and (3) diversity peaks at mid-succession. Testing general patterns of succession requires estimates of variation in trajectories within and among replicate communities. We followed replicate aquatic communities found within leaves of purple pitcher plants (Sarracenia purpurea) to test these three hypotheses. We found that stability of individual communities initially decreased, but then increased in older communities. Predation was highest in younger leaves but then declined, while competition was likely strongest in older leaves, as resources declined through time. Higher levels of predation and competition corresponded with periods of higher stability. As predicted, heterogeneity among communities decreased with age, suggesting that communities became more similar over time. Changes in diversity depended on trophic level. The diversity of bacteria slightly declined over time, but the diversity of consumers of bacteria increased linearly and strongly throughout succession. We suggest that studies need to focus on the variety of environmental drivers of succession, which are likely to vary through time and across habitats. PMID:22430372

  20. Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health

    PubMed Central

    Köberl, Martina; Müller, Henry; Ramadan, Elshahat M.; Berg, Gabriele

    2011-01-01

    Background To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. Methodology/Principal Findings We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. Conclusions/Significance After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems. PMID:21912695

  1. [Diversity of plant in Jiaxing Shijiuyang ecological wetland for drinking water during operation].

    PubMed

    Shen, Ya-Qiang; Wei, Hong-Bin; Cheng, Wang-Da; Zhang, Hong-Mei; Wang, Wei-Dong; Yin, Cheng-Qing

    2011-10-01

    The Shijiuyang ecological wetland for drinking water of Jiaxing City, Zhejiang Province is one of the biggest constructed wetlands for water resource protection in China. To ensure a deep understanding of the present status of the wetland vegetation of Shijiuyang ecological wetland which has been run for 2.5 years and provide support for the vegetation management of ecological wetland, systematic investigation was carried out by using plot method and quadrat method in October to November, 2010. The species composition, dynamics of plant diversity and the biomass production during operation were analyzed. Altogether 70 species belonging to 28 families and 62 genera were recorded. Among them, there were 26 wetland plants, 20 mesophytes, 14 emergent, 4 submerged, 6 floating ones. Compared with the preliminary stage, the species numbers of wetland plants increased significantly from 15 species to 70 species. The spatial pattern of riparian species diversity was examined by adopting the Simpson index and Shannon-Wiener index as species diversity indices. The results showed that the riparian species diversity was higher in the west of the Beijiaohe river (Simpson index = 0.468 3, Shannon-Wiener index = 0.835 2) than that in the south of the Dongsheng Road (Simpson index = 0.357 6, Shannon-Wiener index = 0.660 4). The analyses of quantitative characteristics of wetland vegetation showed that the plants in the root-channel purification zone in the south of the Dongsheng Road grew better than those in the west of the Beijiaohe river. With regard to the riparian vegetation, the riparian plants in the west of the Beijiaohe river were more abundant. The mean biomass production (dry weight) in the root-channel purification zone was 1.73 kg x m(-2) and the total area was 9.12 x 10(4) m2, so the total biomass production was estimated to be 157.8 t. In the same way, the mean riparian vegetation biomass production(dry weight) was 0.83 kg x m(-2) and the total vegetation area was 3.75 x 10(4) m2, so the total riparian vegetation biomass production(dry weight) was estimated as 31.1 t. PMID:22279896

  2. Assessment, Equity, and Diversity in Reforming America's Schools.

    ERIC Educational Resources Information Center

    Winfield, Linda F.; Woodard, Michael D.

    1994-01-01

    National standards and assessments (President Clinton's Goals 2000 Act) are being proposed to improve schools. This article reviews the bill and examines equity issues, including disparities in instructional conditions among racial/ethnic groups. Using tests to change teaching and learning reflects overreliance on top-down policy, distrust of…

  3. Self-Assessment and Dialogue as Tools for Appreciating Diversity

    ERIC Educational Resources Information Center

    O'Neal, Gwenelle S.

    2012-01-01

    As social work educators continue to examine methods and techniques to provide meaningful knowledge about racism and discrimination, the role of self-assessment and dialogue should also be explored. This teaching note presents a tool for students and educators to use in considering literature discrimination and increasing awareness of…

  4. Self-Assessment and Dialogue as Tools for Appreciating Diversity

    ERIC Educational Resources Information Center

    O'Neal, Gwenelle S.

    2012-01-01

    As social work educators continue to examine methods and techniques to provide meaningful knowledge about racism and discrimination, the role of self-assessment and dialogue should also be explored. This teaching note presents a tool for students and educators to use in considering literature discrimination and increasing awareness of…

  5. The Bacterial and Fungal Diversity of an Aged PAH- and Heavy Metal-Contaminated Soil is Affected by Plant Cover and Edaphic Parameters.

    PubMed

    Bourceret, Amélia; Cébron, Aurélie; Tisserant, Emilie; Poupin, Pascal; Bauda, Pascale; Beguiristain, Thierry; Leyval, Corinne

    2016-04-01

    Industrial wasteland soils with aged PAH and heavy metal contaminations are environments where pollutant toxicity has been maintained for decades. Although the communities may be well adapted to the presence of stressors, knowledge about microbial diversity in such soils is scarce. Soil microbial community dynamics can be driven by the presence of plants, but the impact of plant development on selection or diversification of microorganisms in these soils has not been established yet. To test these hypotheses, aged-contaminated soil samples from a field trial were collected. Plots planted with alfalfa were compared to bare soil plots, and bacterial and fungal diversity and abundance were assessed after 2 and 6 years. Using pyrosequencing of 16S rRNA gene and ITS amplicons, we showed that the bacterial community was dominated by Proteobacteria, Actinobacteria, and Bacteroidetes and was characterized by low Acidobacteria abundance, while the fungal community was mainly represented by members of the Ascomycota. The short-term toxic impact of pollutants usually reduces the microbial diversity, yet in our samples bacterial and fungal species richness and diversity was high suggesting that the community structure and diversity adapted to the contaminated soil over decades. The presence of plants induced higher bacterial and fungal diversity than in bare soil. It also increased the relative abundance of bacterial members of the Actinomycetales, Rhizobiales, and Xanthomonadales orders and of most fungal orders. Multivariate analysis showed correlations between microbial community structure and heavy metal and PAH concentrations over time, but also with edaphic parameters (C/N, pH, phosphorus, and nitrogen concentrations). PMID:26440298

  6. Plant diversity does not buffer drought effects on early-stage litter mass loss rates and microbial properties.

    PubMed

    Vogel, Anja; Eisenhauer, Nico; Weigelt, Alexandra; Scherer-Lorenzen, Michael

    2013-09-01

    Human activities are decreasing biodiversity and changing the climate worldwide. Both global change drivers have been shown to affect ecosystem functioning, but they may also act in concert in a non-additive way. We studied early-stage litter mass loss rates and soil microbial properties (basal respiration and microbial biomass) during the summer season in response to plant species richness and summer drought in a large grassland biodiversity experiment, the Jena Experiment, Germany. In line with our expectations, decreasing plant diversity and summer drought decreased litter mass loss rates and soil microbial properties. In contrast to our hypotheses, however, this was only true for mass loss of standard litter (wheat straw) used in all plots, and not for plant community-specific litter mass loss. We found no interactive effects between global change drivers, that is, drought reduced litter mass loss rates and soil microbial properties irrespective of plant diversity. High mass loss rates of plant community-specific litter and low responsiveness to drought relative to the standard litter indicate that soil microbial communities were adapted to decomposing community-specific plant litter material including lower susceptibility to dry conditions during summer months. Moreover, higher microbial enzymatic diversity at high plant diversity may have caused elevated mass loss of standard litter. Our results indicate that plant diversity loss and summer drought independently impede soil processes. However, soil decomposer communities may be highly adapted to decomposing plant community-specific litter material, even in situations of environmental stress. Results of standard litter mass loss moreover suggest that decomposer communities under diverse plant communities are able to cope with a greater variety of plant inputs possibly making them less responsive to biotic changes. PMID:23606531

  7. SOURCE ASSESSMENT: GLASS CONTAINER MANUFACTURING PLANTS

    EPA Science Inventory

    The report summarizes results of a study to gather and analyze background information and technical data related to air emissions from glass container manufacturing operations. It covers emissions from three plant areas: raw materials preparation and handling, glass melting, and ...

  8. Coastal plants : chemical sensitivities and risk assessments

    EPA Science Inventory

    The ability of plant-dominated ecosystems to improve water quality and provide habitat for biodiversity are important ecological services. These services are impacted by natural and anthropogenic stressors which includes contaminant toxicity. Scientific information describing the...

  9. Organic Farming and Landscape Structure: Effects on Insect-Pollinated Plant Diversity in Intensively Managed Grasslands

    PubMed Central

    Power, Eileen F.; Kelly, Daniel L.; Stout, Jane C.

    2012-01-01

    Parallel declines in insect-pollinated plants and their pollinators have been reported as a result of agricultural intensification. Intensive arable plant communities have previously been shown to contain higher proportions of self-pollinated plants compared to natural or semi-natural plant communities. Though intensive grasslands are widespread, it is not known whether they show similar patterns to arable systems nor whether local and/or landscape factors are influential. We investigated plant community composition in 10 pairs of organic and conventional dairy farms across Ireland in relation to the local and landscape context. Relationships between plant groups and local factors (farming system, position in field and soil parameters) and landscape factors (e.g. landscape complexity) were investigated. The percentage cover of unimproved grassland was used as an inverse predictor of landscape complexity, as it was negatively correlated with habitat-type diversity. Intensive grasslands (organic and conventional) contained more insect-pollinated forbs than non-insect pollinated forbs. Organic field centres contained more insect-pollinated forbs than conventional field centres. Insect-pollinated forb richness in field edges (but not field centres) increased with increasing landscape complexity (% unimproved grassland) within 1, 3, 4 and 5km radii around sites, whereas non-insect pollinated forb richness was unrelated to landscape complexity. Pollination systems within intensive grassland communities may be different from those in arable systems. Our results indicate that organic management increases plant richness in field centres, but that landscape complexity exerts strong influences in both organic and conventional field edges. Insect-pollinated forb richness, unlike that for non-insect pollinated forbs, showed positive relationships to landscape complexity reflecting what has been documented for bees and other pollinators. The insect-pollinated forbs, their pollinators and landscape context are clearly linked. This needs to be taken into account when managing and conserving insect-pollinated plant and pollinator communities. PMID:22666450

  10. Spatiotemporal patterns of induced resistance and susceptibility linking diverse plant parasites.

    PubMed

    Mouttet, Raphaëlle; Kaplan, Ian; Bearez, Philippe; Amiens-Desneux, Edwige; Desneux, Nicolas

    2013-12-01

    Induced defenses mediate interactions between parasites sharing the same host plant, but the outcomes of these interactions are challenging to predict because of spatiotemporal variation in plant responses and differences in defense pathways elicited by herbivores or pathogens. Dissecting these mediating factors necessitates an approach that encompasses a diversity of parasitic feeding styles and tracks interactions over space and time. We tested indirect plant-mediated relationships across three tomato (Solanum lycopersicum) consumers: (1) the fungal pathogen-powdery mildew, Oidium neolycopersici; (2) a sap-feeding insect-silverleaf whitefly, Bemisia tabaci; and (3) a chewing insect-the leaf miner, Tuta absoluta. Further, we evaluated insect/pathogen responses on local vs. systemic leaves and over short (1 day) vs. long (4 days) time scales. Overall, we documented: (1) a bi-directional negative effect between O. neolycopersici and B. tabaci; (2) an asymmetrical negative effect of B. tabaci on T. absoluta; and (3) an asymmetrical positive effect of T. absoluta on O. neolycopersici. Spatiotemporal patterns varied depending on the species pair (e.g., whitefly effects on leaf miner performance were highly localized to the induced leaf, whereas effects on pathogen growth were both local and systemic). These results highlight the context-dependent effects of induced defenses on a diverse community of tomato parasites. Notably, the outcomes correspond to those predicted by phytohormonal theory based on feeding guild differences with key implications for the recent European invasion by T. absoluta. PMID:23851986

  11. Diversity and regulation of plant Ca2+ pumps: insights from expression in yeast

    NASA Technical Reports Server (NTRS)

    Sze, H.; Liang, F.; Hwang, I.; Curran, A. C.; Harper, J. F.; Evans, M. L. (Principal Investigator)

    2000-01-01

    The spatial and temporal regulation of calcium concentration in plant cells depends on the coordinate activities of channels and active transporters located on different organelles and membranes. Several Ca2+ pumps have been identified and characterized by functional expression of plant genes in a yeast mutant (K616). This expression system has opened the way to a genetic and biochemical characterization of the regulatory and catalytic features of diverse Ca2+ pumps. Plant Ca(2+)-ATPases fall into two major types: AtECA1 represents one of four or more members of the type IIA (ER-type) Ca(2+)-ATPases in Arabidopsis, and AtACA2 is one of seven or more members of the type IIB (PM-type) Ca(2+)-ATPases that are regulated by a novel amino terminal domain. Type IIB pumps are widely distributed on membranes, including the PM (plasma membrane), vacuole, and ER (endoplasmic reticulum). The regulatory domain serves multiple functions, including autoinhibition, calmodulin binding, and sites for modification by phosphorylation. This domain, however, is considerably diverse among several type IIB ATPases, suggesting that the pumps are differentially regulated. Understanding of Ca2+ transporters at the molecular level is providing insights into their roles in signaling networks and in regulating fundamental processes of cell biology.

  12. Diversity of maize shoot apical meristem architecture and its relationship to plant morphology.

    PubMed

    Thompson, Addie M; Yu, Jianming; Timmermans, Marja C P; Schnable, Patrick; Crants, James C; Scanlon, Michael J; Muehlbauer, Gary J

    2015-05-01

    The shoot apical meristem contains a pool of undifferentiated stem cells and controls initiation of all aerial plant organs. In maize (Zea mays), leaves are formed throughout vegetative development; on transition to floral development, the shoot meristem forms the tassel. Due to the regulated balance between stem cell maintenance and organogenesis, the structure and morphology of the shoot meristem are constrained during vegetative development. Previous work identified loci controlling meristem architecture in a recombinant inbred line population. The study presented here expanded on this by investigating shoot apical meristem morphology across a diverse set of maize inbred lines. Crosses of these lines to common parents showed varying phenotypic expression in the F1, with some form of heterosis occasionally observed. An investigation of meristematic growth throughout vegetative development in diverse lines linked the timing of reproductive transition to flowering time. Phenotypic correlations of meristem morphology with adult plant traits showed an association between the meristem and flowering time, leaf shape, and yield traits, revealing links between the control and architecture of undifferentiated and differentiated plant organs. Finally, quantitative trait loci mapping was utilized to map the genetic architecture of these meristem traits in two divergent populations. Control of meristem architecture was mainly population-specific, with 15 total unique loci mapped across the two populations with only one locus identified in both populations. PMID:25748433

  13. Plant P450s as versatile drivers for evolution of species-specific chemical diversity

    PubMed Central

    Hamberger, Björn; Bak, Søren

    2013-01-01

    The irreversible nature of reactions catalysed by P450s makes these enzymes landmarks in the evolution of plant metabolic pathways. Founding members of P450 families are often associated with general (i.e. primary) metabolic pathways, restricted to single copy or very few representatives, indicative of purifying selection. Recruitment of those and subsequent blooms into multi-member gene families generates genetic raw material for functional diversification, which is an inherent characteristic of specialized (i.e. secondary) metabolism. However, a growing number of highly specialized P450s from not only the CYP71 clan indicate substantial contribution of convergent and divergent evolution to the observed general and specialized metabolite diversity. We will discuss examples of how the genetic and functional diversification of plant P450s drives chemical diversity in light of plant evolution. Even though it is difficult to predict the function or substrate of a P450 based on sequence similarity, grouping with a family or subfamily in phylogenetic trees can indicate association with metabolism of particular classes of compounds. Examples will be given that focus on multi-member gene families of P450s involved in the metabolic routes of four classes of specialized metabolites: cyanogenic glucosides, glucosinolates, mono- to triterpenoids and phenylpropanoids. PMID:23297350

  14. Plant P450s as versatile drivers for evolution of species-specific chemical diversity.

    PubMed

    Hamberger, Björn; Bak, Søren

    2013-02-19

    The irreversible nature of reactions catalysed by P450s makes these enzymes landmarks in the evolution of plant metabolic pathways. Founding members of P450 families are often associated with general (i.e. primary) metabolic pathways, restricted to single copy or very few representatives, indicative of purifying selection. Recruitment of those and subsequent blooms into multi-member gene families generates genetic raw material for functional diversification, which is an inherent characteristic of specialized (i.e. secondary) metabolism. However, a growing number of highly specialized P450s from not only the CYP71 clan indicate substantial contribution of convergent and divergent evolution to the observed general and specialized metabolite diversity. We will discuss examples of how the genetic and functional diversification of plant P450s drives chemical diversity in light of plant evolution. Even though it is difficult to predict the function or substrate of a P450 based on sequence similarity, grouping with a family or subfamily in phylogenetic trees can indicate association with metabolism of particular classes of compounds. Examples will be given that focus on multi-member gene families of P450s involved in the metabolic routes of four classes of specialized metabolites: cyanogenic glucosides, glucosinolates, mono- to triterpenoids and phenylpropanoids. PMID:23297350

  15. Endophytic fungi from medicinal plant Bauhinia forficata : Diversity and biotechnological potential

    PubMed Central

    Bezerra, Jadson D.P.; Nascimento, Carlos C.F.; Barbosa, Renan do N.; da Silva, Dianny C.V.; Svedese, Virgínia M.; Silva-Nogueira, Eliane B.; Gomes, Bruno S.; Paiva, Laura M.; Souza-Motta, Cristina M.

    2015-01-01

    Bauhinia forficata is native to South America and used with relative success in the folk medicine in Brazil. The diversity, antibacterial activity, and extracellular hydrolytic enzymes of endophytic fungi associated with this plant were studied. Plant samples, which included leaves, sepals, stems, and seeds, were used. Ninety-five endophytic fungal were isolated (18 from leaves, 22 from sepals, 46 from stems, and nine from seeds), comprising 28 species. The most frequently isolated species were Acremonium curvulum (9.5%), Aspergillus ochraceus (7.37%), Gibberella fujikuroi (10.53%), Myrothecium verrucaria (10.53%) and Trichoderma piluliferum (7.37%). Diversity and species richness were higher in stem tissues, and Sorensen’s index of similarity between the tissues was low. Eleven fungi showed antibacterial activity. Aspergillus ochraceus , Gibberella baccata , Penicillium commune , and P. glabrum were those with the greatest antibacterial activity against Staphylococcus aureus and/or Streptococcus pyogenes . Thirteen species showed proteolytic activity, particularly Phoma putaminum . Fourteen species were cellulase positive, particularly the Penicillium species and Myrmecridium schulzeri . All isolates tested were xylanase positive and 10 showed lipolytic activity, especially Penicillium glabrum . It is clear that the endophytic fungi from B. forficata have potential for the production of bioactive compounds and may be a source of new therapeutic agents for the effective treatment of diseases in humans, other animals, and plants. To our knowledge, this is the first study of endophytic fungi from different tissues of B. forficata and their biotechnological potential. PMID:26221088

  16. Endophytic fungi from medicinal plant Bauhinia forficata: Diversity and biotechnological potential.

    PubMed

    Bezerra, Jadson D P; Nascimento, Carlos C F; Barbosa, Renan do N; da Silva, Dianny C V; Svedese, Virgínia M; Silva-Nogueira, Eliane B; Gomes, Bruno S; Paiva, Laura M; Souza-Motta, Cristina M

    2015-03-01

    Bauhinia forficata is native to South America and used with relative success in the folk medicine in Brazil. The diversity, antibacterial activity, and extracellular hydrolytic enzymes of endophytic fungi associated with this plant were studied. Plant samples, which included leaves, sepals, stems, and seeds, were used. Ninety-five endophytic fungal were isolated (18 from leaves, 22 from sepals, 46 from stems, and nine from seeds), comprising 28 species. The most frequently isolated species were Acremonium curvulum (9.5%), Aspergillus ochraceus (7.37%), Gibberella fujikuroi (10.53%), Myrothecium verrucaria (10.53%) and Trichoderma piluliferum (7.37%). Diversity and species richness were higher in stem tissues, and Sorensen's index of similarity between the tissues was low. Eleven fungi showed antibacterial activity. Aspergillus ochraceus , Gibberella baccata , Penicillium commune , and P. glabrum were those with the greatest antibacterial activity against Staphylococcus aureus and/or Streptococcus pyogenes . Thirteen species showed proteolytic activity, particularly Phoma putaminum . Fourteen species were cellulase positive, particularly the Penicillium species and Myrmecridium schulzeri . All isolates tested were xylanase positive and 10 showed lipolytic activity, especially Penicillium glabrum . It is clear that the endophytic fungi from B. forficata have potential for the production of bioactive compounds and may be a source of new therapeutic agents for the effective treatment of diseases in humans, other animals, and plants. To our knowledge, this is the first study of endophytic fungi from different tissues of B. forficata and their biotechnological potential. PMID:26221088

  17. Global concordance in diversity patterns of vascular plants and terrestrial vertebrates.

    PubMed

    Qian, Hong; Ricklefs, Robert E

    2008-06-01

    The factors that determine large-scale patterns of species richness are poorly understood. In particular, biologists have not determined the relative roles of taxon-specific characteristics that influence diversification and distribution, and region-specific features that promote and constrain diversity. We show that the numbers of species of vascular plants and of four terrestrial vertebrate taxa (mammals, birds, reptiles and amphibians) vary in parallel across 296 geographic areas covering most of the globe, even after accounting for sample area, climate, topographic heterogeneity and differences between continents. Thus, a common set of regional characteristics and processes appears to shape patterns of species richness in a diverse set of taxa, despite substantial differences in their biological traits. PMID:18318717

  18. [Effects of tourism disturbance on plant diversity in Qingshan Lake scenic area of Zhejiang Province].

    PubMed

    Lu, Qing-Bin; You, Wei-Yun; Zhao, Chang-Jie; Wang, Xiang-Wei; Meng-Xiang, Xiu

    2011-02-01

    From May 2007 to June 2008, an investigation was made on the changes of plant community in Qingshan Lake scenic area of Zhejiang Province under the effects of tourism disturbance. With the increase of tourism disturbance, the importance value of the plants was mainly fastened on a few species such as Pinus hwangshanensis, apt to decrease for tree and shrub species and to increase for herb species, and the individuals of the plants increased. The values of richness index (D) and diversity index (H) were in the order of medium disturbance > slight disturbance > severe disturbance, while the evenness index (J) value was in the order of medium disturbance > severe disturbance > slight disturbance. At the same vegetation layers, only a few species such as Cinnamomum camphora existed under different disturbances, and thereby, the similarity index values were smaller than 0.500. Slight disturbance affected coniferous forest most, with the average values of D, H, and J being the lowest (1.188, 1.056, and 0.697, respectively); severe disturbance affected broadleaf forest and shrub-herbage most, with the D value (2.013) of shrub-herbage and the H value (1.286) and J value (0.807) of broadleaf forest being the lowest; while medium disturbance was favorable to the increase of plant diversity and to the normal exertion of ecosystem function. The eco-safety of the structural elements of plant community in the scenic area was threatened to some extent, resulting in the reduction of indigenous species such as Sinocalycanthus chinensis and the incursion of exotic species as Setaria viridis. PMID:21608239

  19. A structural equation model analysis of postfire plant diversity in California shrublands

    USGS Publications Warehouse

    Grace, J.B.; Keeley, J.E.

    2006-01-01

    This study investigates patterns of plant diversity following wildfires in fire-prone shrublands of California, seeks to understand those patterns in terms of both local and landscape factors, and considers the implications for fire management. Ninety study sites were established following extensive wildfires in 1993, and 1000-m2 plots were used to sample a variety of parameters. Data on community responses were collected for five years following fire. Structural equation modeling (SEM) was used to relate plant species richness to plant abundance, fire severity, abiotic conditions, within-plot heterogeneity, stand age, and position in the landscape. Temporal dynamics of average richness response was also modeled. Richness was highest in the first year following fire, indicating postfire enhancement of diversity. A general decline in richness over time was detected, with year-to-year variation attributable to annual variations in precipitation. Peak richness in the landscape was found where (1) plant abundance was moderately high, (2) within-plot heterogeneity was high, (3) soils were moderately low in nitrogen, high in sand content, and with high rock cover, (4) fire severity was low, and (5) stands were young prior to fire. Many of these characteristics were correlated with position in the landscape and associated conditions. We infer from the SEM results that postfire richness in this system is strongly influenced by local conditions and that these conditions are, in turn, predictably related to landscape-level conditions. For example, we observed that older stands of shrubs were characterized by more severe fires, which were associated with a low recovery of plant cover and low richness. These results may have implications for the use of prescribed fire in this system if these findings extrapolate to prescribed burns as we would expect. ?? 2006 by the Ecological Society of America.

  20. Abundance- and functional-based mechanisms of plant diversity loss with fertilization in the presence and absence of herbivores.

    PubMed

    Yang, Zhongling; Hautier, Yann; Borer, Elizabeth T; Zhang, Chunhui; Du, Guozhen

    2015-09-01

    Nutrient supply and herbivores can regulate plant species composition, biodiversity and functioning of terrestrial ecosystems. Nutrient enrichment frequently increases plant productivity and decreases diversity while herbivores tend to maintain plant diversity in productive systems. However, the mechanisms by which nutrient enrichment and herbivores regulate plant diversity remain unclear. Abundance-based mechanisms propose that fertilization leads to the extinction of rare species due to random loss of individuals of all species. In contrast, functional-based mechanisms propose that species exclusion is based on functional traits which are disadvantageous under fertilized conditions. We tested mechanistic links between fertilization and diversity loss in the presence or absence of consumers using data from a 4-year fertilization and fencing experiment in an alpine meadow. We found that both abundance- and functional-based mechanisms simultaneously affected species loss in the absence of herbivores while only abundance-based mechanisms affected species loss in the presence of herbivores. Our results indicate that an abundance-based mechanism may consistently play a role in the loss of plant diversity with fertilization, and that diversity decline is driven primarily by the loss of rare species regardless of a plant's functional traits and whether or not herbivores are present. Increasing efforts to conserve rare species in the context of ecosystem eutrophication is a central challenge for grazed grassland ecosystems. PMID:25969333

  1. Plant diversity effects on leaching of nitrate, ammonium, and dissolved organic nitrogen from an experimental grassland

    NASA Astrophysics Data System (ADS)

    Leimer, Sophia; Oelmann, Yvonne; Wirth, Christian; Wilcke, Wolfgang

    2014-05-01

    Leaching of nitrogen (N) from soil represents a resource loss and, in particular leaching of nitrate, can threaten drinking water quality. As plant diversity leads to a more exhaustive resource use, we investigated the effects of plant species richness, functional group richness, and the presence of specific functional groups on nitrate, ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from an experimental grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. The experiment is located in Jena, Germany, and consists of 82 plots with 1, 2, 4, 8, 16, or 60 plant species and 1-4 functional groups (legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs). Nitrate, ammonium, and TDN concentrations in soil solution in the 0-0.3 m soil layer were measured every second week during 4 years on 62 plots and DON concentrations were calculated as difference between TDN and inorganic N. Missing concentrations in soil solution were estimated using a Bayesian statistical model. Downward water fluxes (DF) per plot from the 0-0.3 m soil layer were simulated in weekly resolution with a water balance model in connection with a Bayesian model for simulating missing soil water content measurements. To obtain annual nitrate, ammonium, and DON leaching from the 0-0.3 m soil layer per plot, we multiplied the respective concentrations in soil solution with DF and aggregated the data to annual sums. TDN leaching resulted from summation of nitrate, ammonium, and DON leaching. DON leaching contributed most to TDN leaching, particularly in plots without legumes. Dissolved inorganic N leaching in this grassland was dominated by nitrate. The amount of annual ammonium leaching was small and little influenced by plant diversity. Species richness affected DON leaching only in the fourth and last investigated year, possibly because of a delayed soil biota effect that increased microbial transformation of organic N to inorganic N in species-rich mixtures or because of complementary resource use of amino-acid DON of species-rich mixtures. Nitrate and TDN leaching generally decreased with increasing species richness likely because of more exhaustive resource use of more diverse plant mixtures. Functional group richness did not have a significant effect on nitrate, ammonium, DON, and TDN leaching. Legumes increased and grasses decreased nitrate, DON, and TDN leaching because of their N-fixing ability and their extensive rooting system, respectively. TDN leaching was highest in the first year after conversion from arable to grassland which can be related to former fertilization. Quantitative differences in nitrate leaching between plant diversity treatments were also highest in the first year after conversion. However, the percentage reduction of nitrate leaching by species richness, the presence of grasses, or the presence of small herbs increased with time since land-use change possibly because of a strengthening of diversity effects with time. We conclude that especially shortly after land-use change from fertilized arable land to unfertilized grassland, N leaching, in particular nitrate leaching, can be reduced considerably if highly diverse mixtures without legumes are established.

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

    USGS Publications Warehouse

    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 gradients and other factors. We suggest that at least some portions of vegetation maps created at a coarser level of resolution be validated at a higher level of resolution.

  3. Risk management tools and the case study Brassica napus: evaluating possible effects of genetically modified plants on soil microbial diversity.

    PubMed

    Canfora, Loredana; Sbrana, Cristiana; Avio, Luciano; Felici, Barbara; Scatà, Maria Carmela; Neri, Ulderico; Benedetti, Anna

    2014-09-15

    The cultivation of GMPs in Europe raises many questions about the environmental risks, in particular about their ecological impact on non-target organisms and on soil properties. The aim of a multidisciplinary group engaged in a LIFE+project (MAN-GMP-ITA) was to validate and improve an existing environmental risk assessment (ERA) methodology on GMPs within the European legislative framework on GMOs. Given the impossibility of evaluating GMO impact directly, as GMPs are banned in Italy, GMPs have not been used at any stage of the project. The project thus specifically focused on the conditions for the implementation of ERA in different areas of Italy, with an emphasis on some sensitive and protected areas located in the North, Centre, and South of the country, in order to lay the necessary baseline for evaluating the possible effects of a GMP on soil communities. Our sub-group carried out soil analyses in order to obtain soil health and fertility indicators to be used as baselines in the ERA model. Using various methods of chemical, biochemical, functional and genetic analysis, our study assessed the changes in diversity and functionality of bacterial populations, and arbuscular mycorrhizal fungi. The results show that plant identity and growth, soil characteristics, and field site climatic parameters are key factors in contributing to variation in microbial community structure and diversity, thus validating our methodological approach. Our project has come to the conclusion that the uneven composition and biological-agronomical quality of soils need to be taken into consideration in a risk analysis within the framework of ERA for the release of genetically modified plants. PMID:25014185

  4. Importance of Mediator complex in the regulation and integration of diverse signaling pathways in plants.

    PubMed

    Samanta, Subhasis; Thakur, Jitendra K

    2015-01-01

    Basic transcriptional machinery in eukaryotes is assisted by a number of cofactors, which either increase or decrease the rate of transcription. Mediator complex is one such cofactor, and recently has drawn a lot of interest because of its integrative power to converge different signaling pathways before channeling the transcription instructions to the RNA polymerase II machinery. Like yeast and metazoans, plants do possess the Mediator complex across the kingdom, and its isolation and subunit analyses have been reported from the model plant, Arabidopsis. Genetic, and molecular analyses have unraveled important regulatory roles of Mediator subunits at every stage of plant life cycle starting from flowering to embryo and organ development, to even size determination. It also contributes immensely to the survival of plants against different environmental vagaries by the timely activation of its resistance mechanisms. Here, we have provided an overview of plant Mediator complex starting from its discovery to regulation of stoichiometry of its subunits. We have also reviewed involvement of different Mediator subunits in different processes and pathways including defense response pathways evoked by diverse biotic cues. Wherever possible, attempts have been made to provide mechanistic insight of Mediator's involvement in these processes. PMID:26442070

  5. Importance of Mediator complex in the regulation and integration of diverse signaling pathways in plants

    PubMed Central

    Samanta, Subhasis; Thakur, Jitendra K.

    2015-01-01

    Basic transcriptional machinery in eukaryotes is assisted by a number of cofactors, which either increase or decrease the rate of transcription. Mediator complex is one such cofactor, and recently has drawn a lot of interest because of its integrative power to converge different signaling pathways before channeling the transcription instructions to the RNA polymerase II machinery. Like yeast and metazoans, plants do possess the Mediator complex across the kingdom, and its isolation and subunit analyses have been reported from the model plant, Arabidopsis. Genetic, and molecular analyses have unraveled important regulatory roles of Mediator subunits at every stage of plant life cycle starting from flowering to embryo and organ development, to even size determination. It also contributes immensely to the survival of plants against different environmental vagaries by the timely activation of its resistance mechanisms. Here, we have provided an overview of plant Mediator complex starting from its discovery to regulation of stoichiometry of its subunits. We have also reviewed involvement of different Mediator subunits in different processes and pathways including defense response pathways evoked by diverse biotic cues. Wherever possible, attempts have been made to provide mechanistic insight of Mediator's involvement in these processes. PMID:26442070

  6. Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants

    PubMed Central

    Granada, Camille E.; Strochein, Marcos; Vargas, Luciano K.; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M.P.

    2014-01-01

    This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405

  7. Consequences of plant-chemical diversity for domestic goat food preference in Mediterranean forests

    NASA Astrophysics Data System (ADS)

    Baraza, Elena; Hódar, José A.; Zamora, Regino

    2009-01-01

    The domestic goat, a major herbivore in the Mediterranean basin, has demonstrated a strong ability to adapt its feeding behaviour to the chemical characteristics of food, selecting plants according to their nutritive quality. In this study, we determine some chemical characteristics related to plant nutritional quality and its variability among and within five tree species, these being the main components of the mountain forests of SE Spain, with the aim of determining their influence on food selection by this generalist herbivore. We analyse nitrogen, total phenols, condensed tannins and fibre concentration as an indicator of the nutritive value of the different trees. To determine the preference by the domestic goat, we performed two types of feeding-choice assays, where goats had to select between different species or between branches of the same species but from trees of different nutritional quality. The analysis of the plant nutritional quality showed significant differences in the chemical characteristics between species, and a high variability within species. However, when faced with different tree species, the domestic goat selected some of them but showed striking individual differences between goats. When selecting between trees of the same species, the goats showed no differential selection. This limited effect of chemical plant characteristics, together with the variability in foraging behaviour, resulted in a widespread consumption of diverse plant species, which can potentially modulate the effect of the goat on vegetation composition, and open the way for the conservation of traditional livestock grazing on natural protected areas.

  8. Marine Macroalgal Diversity Assessment of Saba Bank, Netherlands Antilles

    PubMed Central

    Littler, Mark M.; Littler, Diane S.; Brooks, Barrett L.

    2010-01-01

    Background Located in the Dutch Windward Islands, Saba Bank is a flat-topped seamount (20–45 m deep in the shallower regions). The primary goals of the survey were to improve knowledge of biodiversity for one of the world's most significant, but little-known, seamounts and to increase basic data and analyses to promote the development of an improved management plan. Methodology/Principal Findings Our team of three divers used scuba to collect algal samples to depths of 50 m at 17 dive sites. Over 360 macrophyte specimens (12 putative new species) were collected, more than 1,000 photographs were taken in truly exceptional habitats, and three astonishing new seaweed community types were discovered. These included: (1) “Field of Greens” (N 17°30.620′, W 63°27.707′) dominated by green seaweeds as well as some filamentous reds, (2) “Brown Town” (N 17°28.027′, W 63°14.944′) dominated by large brown algae, and (3) “Seaweed City” (N 17°26.485′, W 63°16.850′) with a diversity of spectacular fleshy red algae. Conclusions/Significance Dives to 30 m in the more two-dimensional interior habitats revealed particularly robust specimens of algae typical of shallower seagrass beds, but here in the total absence of any seagrasses (seagrasses generally do not grow below 20 m). Our preliminary estimate of the number of total seaweed species on Saba Bank ranges from a minimum of 150 to 200. Few filamentous and thin sheet forms indicative of stressed or physically disturbed environments were observed. A more precise number still awaits further microscopic and molecular examinations in the laboratory. The expedition, while intensive, has only scratched the surface of this unique submerged seamount/atoll. PMID:20505757

  9. Plant diversity and ecosystem multifunctionality peak at intermediate levels of woody cover in global drylands

    PubMed Central

    Soliveres, Santiago; Maestre, Fernando T.; Eldridge, David J.; Delgado-Baquerizo, Manuel; Quero, José Luis; Bowker, Matthew A.; Gallardo, Antonio

    2015-01-01

    Aim The global spread of woody plants into grasslands is predicted to increase over the coming century. While there is general agreement regarding the anthropogenic causes of this phenomenon, its ecological consequences are less certain. We analyzed how woody vegetation of differing cover affects plant diversity (richness and evenness) and multiple ecosystem functions (multifunctionality) in global drylands, and how this changes with aridity. Location 224 dryland sites from all continents except Antarctica widely differing in their environmental conditions (from arid to dry-subhumid sites) and woody covers (from 0 to 100%). Methods Using a standardized field survey, we measured the cover, richness and evenness of perennial vegetation. At each site, we measured 14 ecosystem functions related to soil fertility and the build-up of nutrient pools. These functions are critical for maintaining ecosystem function in drylands. Results Species richness and ecosystem multifunctionality were strongly influenced by woody vegetation, with both variables peaking at relative woody covers (RWC) of 41-60%. This relationship shifted with aridity. We observed linear positive effects of RWC in dry-subhumid sites. These positive trends shifted to hump-shaped RWC-diversity and multifunctionality relationships under semiarid environments. Finally, hump-shaped (richness, evenness) or linear negative (multifunctionality) effects of RWC were found under the most arid conditions. Main conclusions Plant diversity and multifunctionality peaked at intermediate levels of woody cover, although this relationship became increasingly positive under wetter environments. This comprehensive study accounts for multiple ecosystem attributes across a range of woody covers and environmental conditions. Our results help us to reconcile contrasting views of woody encroachment found in current literature and can be used to improve predictions of the likely effects of encroachment on biodiversity and ecosystem services. PMID:25914607

  10. Assessment of relationship between fungal aerosol within a municipal dump and epiphytic mycoflora of crop plants.

    PubMed

    Ropek, Dariusz Roman; Fraczek, Krzysztof; Kozdrój, Jacek; Chmiel, Maria

    2013-01-01

    A field study was performed to assess whether fungal aerosol of a municipal dump may impact on quantitative and qualitative characteristics of epiphytic mycoflora of crop plants cultivated in vicinity of the dump. Sampling sites were located at every side of the dump. Plant samples were collected from field bean, spring wheat and potato. The highest concentration of fungal aerosol was found at the field located south of the dump within the zone of 250 m next to its borders. For this zone, the most numerous and diverse mycoflora was ascertained, and the plants cultivated were the most damaged. The results suggest that the municipal dump was not the source of phytopathogenic fungi; however, different emissions of contaminants from the dump might cause a decline in the intrinsic plant resistance against the pathogens. PMID:22870959

  11. Native wildflower plantings support wild bee abundance and diversity in agricultural landscapes across the United States.

    PubMed

    Williams, Neal M; Ward, Kimiora L; Pope, Nathaniel; Isaacs, Rufus; Wilson, Julianna; May, Emily A; Ellis, Jamie; Daniels, Jaret; Pence, Akers; Ullmann, Katharina; Peters, Jeff

    2015-12-01

    Global trends in pollinator-dependent crops have raised awareness of the need to support managed and wild bee populations to ensure sustainable crop production. Provision of sufficient forage resources is a key element for promoting bee populations within human impacted landscapes, particularly those in agricultural lands where demand for pollination service is high and land use and management practices have reduced available flowering resources. Recent government incentives in North America and Europe support the planting of wildflowers to benefit pollinators; surprisingly, in North America there has been almost no rigorous testing of the performance of wildflower mixes, or their ability to support wild bee abundance and diversity. We tested different wildflower mixes in a spatially replicated, multiyear study in three regions of North America where production of pollinator-dependent crops is high: Florida, Michigan, and California. In each region, we quantified flowering among wildflower mixes composed of annual and perennial species, and with high and low relative diversity. We measured the abundance and species richness of wild bees, honey bees, and syrphid flies at each mix over two seasons. In each region, some but not all wildflower mixes provided significantly greater floral display area than unmanaged weedy control plots. Mixes also attracted greater abundance and richness of wild bees, although the identity of best mixes varied among regions. By partitioning floral display size from mix identity we show the importance of display size for attracting abundant and diverse wild bees. Season-long monitoring also revealed that designing mixes to provide continuous bloom throughout the growing season is critical to supporting the greatest pollinator species richness. Contrary to expectation, perennials bloomed in their first season, and complementarity in attraction of pollinators among annuals and perennials suggests that inclusion of functionally diverse species may provide the greatest benefit. Wildflower mixes may be particularly important for providing resources for some taxa, such as bumble bees, which are known to be in decline in several regions of North America. No mix consistently attained the full diversity that was planted. Further study is needed on how to achieve the desired floral display and diversity from seed mixes. PMID:26910943

  12. Protocol: a rapid and economical procedure for purification of plasmid or plant DNA with diverse applications in plant biology.

    PubMed

    Li, Jian-Feng; Li, Li; Sheen, Jen

    2010-01-01

    Research in plant molecular biology involves DNA purification on a daily basis. Although different commercial kits enable convenient extraction of high-quality DNA from E. coli cells, PCR and agarose gel samples as well as plant tissues, each kit is designed for a particular type of DNA extraction work, and the cost of purchasing these kits over a long run can be considerable. Furthermore, a simple method for the isolation of binary plasmid from Agrobacterium tumefaciens cells with satisfactory yield is lacking. Here we describe an easy protocol using homemade silicon dioxide matrix and seven simple solutions for DNA extraction from E. coli and A. tumefaciens cells, PCR and restriction digests, agarose gel slices, and plant tissues. Compared with the commercial kits, this protocol allows rapid DNA purification from diverse sources with comparable yield and purity at negligible cost. Following this protocol, we have demonstrated: (1) DNA fragments as small as a MYC-epitope tag coding sequence can be successfully recovered from an agarose gel slice; (2) Miniprep DNA from E. coli can be eluted with as little as 5 mul water, leading to high DNA concentrations (>1 mug/mul) for efficient biolistic bombardment of Arabidopsis seedlings, polyethylene glycol (PEG)-mediated Arabidopsis protoplast transfection and maize protoplast electroporation; (3) Binary plasmid DNA prepared from A. tumefaciens is suitable for verification by restriction analysis without the need for large scale propagation; (4) High-quality genomic DNA is readily isolated from several plant species including Arabidopsis, tobacco and maize. Thus, the silicon dioxide matrix-based DNA purification protocol offers an easy, efficient and economical way to extract DNA for various purposes in plant research. PMID:20180960

  13. Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny.

    PubMed

    Mutke, Jens; Jacobs, Rana; Meyers, Katharina; Henning, Tilo; Weigend, Maximilian

    2014-01-01

    The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae), the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae), and the American clade of Urtica (Urticaceae). In the tropical Andes, these often grow together, especially in (naturally or anthropogenically) disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape-Huancabamba Zone (AHZ) between 3 and 8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger toward the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500-3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translate into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is not retrieved in our data. PMID:25346750

  14. Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation

    PubMed Central

    Ægisdóttir, Hafdís Hanna; Kuss, Patrick; Stöcklin, Jürg

    2009-01-01

    Background and Aims Gene flow and genetic variability within and among alpine plant populations can be greatly influenced by the steep environmental gradients and heterogeneous topography of alpine landscapes. In this study, the effects are examined of natural isolation of alpine habitats on genetic diversity and geographic structure in populations of C. thyrsoides, a rare and isolated European Alpine monocarpic perennial with limited seed dispersal capacity. Methods Molecular diversity was analysed for 736 individuals from 32 populations in the Swiss Alps and adjacent Jura mountains using five polymorphic microsatellite loci. Pollen flow was estimated using pollen grain-sized fluorescent powder. In addition, individual-based Bayesian approaches were applied to examine population structure. Key Results High within-population genetic diversity (HE = 0·76) and a relatively low inbreeding coefficient (FIS = 0·022) were found. Genetic differentiation among populations measured with a standardized measure was considerable (G?ST = 0·53). A significant isolation-by-distance