The Experts below are selected from a list of 55488 Experts worldwide ranked by ideXlab platform
Diana R Nemergut - One of the best experts on this subject based on the ideXlab platform.
-
changes in community assembly may shift the relationship between biodiversity and Ecosystem Function
Frontiers in Microbiology, 2014Co-Authors: Joseph E Knelman, Diana R NemergutAbstract:Can differences in community assemblyalter the relationship between biodiver-sity and Ecosystem Function? Pholchanet al. (2013) used a variety of manipu-lations to change microbial communityassembly in sludge reactors and exam-ined the subsequent links between diver-sity and a rare Function, the removal ofendocrinedisruptingcompounds(EDCs).Interestingly, the authors saw no consis-tent differences between shifts in alphadiversity (e.g., species richness and even-ness) and Ecosystem Function, observingan increase, decrease and no difference inthe amount of removal of specific EDCswith increases in diversity. They suggestedthat differences in community assemblymay be driving variation in the rela-tionship between biodiversity and func-tion, a fascinating hypothesis that unitesprocesses in community and Ecosystemecology.Combinations of four processes affectcommunity assembly: dispersal and diver-sification add new taxa to communitieswhile selection and drift affect their rela-tive abundances (Vellend, 2010; Nemergutet al., 2013). Particular research emphasishas been placed on assembly processesthataredriven bydifferences betweentaxa(“niche”) compared to those in whichany such differences are irrelevant to fit-ness(“neutral”)(Hubbell,2001).Likewise,researchers have focused on the roleof stochasticity, where assembly is moreprobabilistic vs. determinism, in whichrandomness does not affect communitydynamics.Nicheandneutralprocessescanoperateinunison(Adler et al., 2007)andboth can be affected by stochastic anddeterministic forces (Fox, 2012). Indeed,extensive data demonstrate that a varietyof factors, including nutrients, produc-tivity, resource availability, successionalstage, and disturbances may affect the rel-ative importance of different communityassembly mechanisms (Chase, 2007, 2010;Ferrenbergetal.,2013;Kardoletal.,2013).However, to our knowledge, no studieshave directly tested how shifts in com-munity assembly may affect the relation-ship between biodiversity and EcosystemFunction.Of course, a great deal of researchhas focused on pairwise combinationsof the interactions between communityassembly, biodiversity and/or Function inisolation. First, a large body of workdemonstrates links between biodiversityand Ecosystem Function (Cardinale et al.,2011; Hooper et al., 2012), even formicrobial systems (Bell et al., 2005; Hsuand Buckley, 2009; Langenheder et al.,2010; Levine et al., 2011; Jousset et al.,2014). However, the nature and strengthof biodiversity Ecosystem Function (BEF)relationships have been widely debatedand strongly depend on the type of func-tion and Ecosystem examined (Grime,1997; Hooper et al., 2005)andthedegree of redundancy within the com-munity (Reich et al., 2012; Jousset et al.,2014). These complexities may be height-ened for microorganisms due to theextraordinary phylogenetic diversity har-bored within microbial communities, andthe fact that a typical microbial commu-nity contains organisms from within avariety of Functional guilds.Second, it is known that differentassemblymechanismsdrivebiodiversityindistinct ways. For example, spatial or tem-poral variation in environmental condi-tions increases biodiversity through nicheprocesses while increases in the diver-sity of the metacommunity or in theratio of immigration/emigration rates canincrease biodiversity through neutral pro-cesses (Vellend, 2010).Finally, a relatively new topic in the lit-erature relates community assembly andEcosystem Function (Fukami et al., 2010;Nemergut et al., 2013). Vital to such aconsideration is the relationship betweenresponse traits, or traits that can interactwithenvironmentalvariationtodeterminespecies distribution and abundance pat-terns, and effect traits, or traits that deter-mine the Functional roles of different taxa(Naeem and Wright, 2003). When com-munities are largely structured by nicheprocesses, variation in the environmentcan directly correlate to effect traits thatare linked to selected response traits(Allison, 2012). However, when commu-nities are structured by neutral processes,Ecosystem Function will primarily dependon effect trait abundances within themetacommunity, dispersal and ecologicaldrift; thus, relationships between varia-tion in the environment and effect traits
-
do we need to understand microbial communities to predict Ecosystem Function a comparison of statistical models of nitrogen cycling processes
Soil Biology & Biochemistry, 2014Co-Authors: Emily B Graham, William R Wieder, Jonathan W Leff, Samantha R Weintraub, Alan R Townsend, Cory C Cleveland, Laurent Philippot, Diana R NemergutAbstract:Despite the central role of microorganisms in biogeochemistry, process models rarely explicitly account for variation in communities. Here, we use statistical models to address a fundamental question in Ecosystem ecology: do we need to better understand microbial communities to accurately predict Ecosystem Function? Nitrogen (N) cycle process rates and associated gene abundances were measured in tropical rainforest soil samples collected in May (early wet season) and October (late wet season). We used stepwise linear regressions to examine the explanatory power of edaphic factors and Functional gene relative abundances alone and in combination for N-cycle processes, using both our full dataset and seasonal subsets of the data. In our full dataset, no models using gene abundance data explained more variation in process rates than models based on edaphic factors alone, and models that contained both edaphic factors and community data did not explain significantly more variation in process rates than edaphic factor models. However, when seasonal datasets were examined separately, microbial predictors enhanced the explanatory power of edaphic predictors on dissimilatory nitrate reduction to ammonium and N2O efflux rates during October. Because there was little variation in the explanatory power of microbial predictors alone between seasonal datasets, our results suggest that environmental factors we did not measure may be more important in structuring communities and regulating processes in October than in May. Thus, temporal dynamics are key to understanding the relationships between edaphic factors, microbial communities and Ecosystem Function in this system. The simple statistical method presented here can accommodate a variety of data types and should help prioritize what forms of data may be most useful in Ecosystem model development.
David Tilman - One of the best experts on this subject based on the ideXlab platform.
-
plant spectral diversity integrates Functional and phylogenetic components of biodiversity and predicts Ecosystem Function
Nature Ecology and Evolution, 2018Co-Authors: Anna K Schweiger, David Tilman, Jeannine Cavenderbares, Philip A Townsend, Sarah E Hobbie, Michael D Madritch, Ran Wang, John A GamonAbstract:Biodiversity promotes Ecosystem Function as a consequence of Functional differences among organisms that enable resource partitioning and facilitation. As the need for biodiversity assessments increases in the face of accelerated global change, novel approaches that are rapid, repeatable and scalable are critical, especially in Ecosystems for which information about species identity and the number of species is difficult to acquire. Here, we present 'spectral diversity'—a spectroscopic index of the variability of electromagnetic radiation reflected from plants measured in the visible, near-infrared and short-wave infrared regions (400–2,400 nm). Using data collected from the Cedar Creek biodiversity experiment (Minnesota, USA), we provide evidence that the dissimilarity of species' leaf spectra increases with Functional dissimilarity and evolutionary divergence time. Spectral diversity at the leaf level explains 51% of total variation in productivity—a proportion comparable to taxonomic (47%), Functional (51%) or phylogenetic diversity (48%)—and performs similarly when calculated from high-resolution canopy image spectra. Spectral diversity is an emerging dimension of plant biodiversity that integrates trait variation within and across species even in the absence of taxonomic, Functional, phylogenetic or abundance information, and has the potential to transform biodiversity assessment because of its scalability to remote sensing.
-
plant diversity soil microbial communities and Ecosystem Function are there any links
Ecology, 2003Co-Authors: William E Holmes, David C White, Aaron D Peacock, David TilmanAbstract:A current debate in ecology centers on the extent to which Ecosystem Function depends on biodiversity. Here, we provide evidence from a long-term field manipulation of plant diversity that soil microbial communities, and the key Ecosystem processes that they mediate, are significantly altered by plant species richness. After seven years of plant growth, we determined the composition and Function of soil microbial communities beneath experimental plant diversity treatments containing 1-16 species. Microbial community bio- mass, respiration, and fungal abundance significantly increased with greater plant diversity, as did N mineralization rates. However, changes in microbial community biomass, activity, and composition largely resulted from the higher levels of plant production associated with greater diversity, rather than from plant diversity per se. Nonetheless, greater plant pro- duction could not explain more rapid N mineralization, indicating that plant diversity affected this microbial process, which controls rates of Ecosystem N cycling. Greater N availability probably contributed to the positive relationship between plant diversity and productivity in the N-limited soils of our experiment, suggesting that plant-microbe in- teractions in soil are an integral component of plant diversity's influence on Ecosystem
Corey J A Bradshaw - One of the best experts on this subject based on the ideXlab platform.
-
mechanisms driving change altered species interactions and Ecosystem Function through global warming
Journal of Animal Ecology, 2010Co-Authors: Lochran W Traill, Navjot S Sodhi, Corey J A BradshawAbstract:Summary 1. We review the mechanisms behind Ecosystem Functions, the processes that facilitate energy transfer along food webs, and the major processes that allow the cycling of carbon, oxygen and nitrogen, and use case studies to show how these have already been, and will continue to be, altered by global warming. 2. Increased temperatures will affect the interactions between heterotrophs and autotrophs (e.g. pollination and seed dispersal), and between heterotrophs (e.g. predators-prey, parasites ⁄ pathogens-hosts), with generally negative ramifications for important Ecosystem services (Functions that provide direct benefit to human society such as pollination) and potential for heightened species co-extinction rates. 3. Mitigation of likely impacts of warming will require, in particular, the maintenance of species diversity as insurance for the provision of basic Ecosystem services. Key to this will be long-term monitoring and focused research that seek to maintain Ecosystem resilience in the face of global warming. 4. We provide guidelines for pursuing research that quantifies the nexus between Ecosystem Function and global warming. These include documentation of key Functional species groups within systems, and understanding the principal outcomes arising from direct and indirect effects of a rapidly warming environment. Localized and targeted research and monitoring, complemented with laboratory work, will determine outcomes for resilience and guide adaptive conservation responses and long-term planning.
Alan K Knapp - One of the best experts on this subject based on the ideXlab platform.
-
relative effects of precipitation variability and warming on tallgrass prairie Ecosystem Function
Biogeosciences, 2011Co-Authors: John M Blair, Melinda D Smith, Jesse B Nippert, Jonathan D Carlisle, Alan K KnappAbstract:Precipitation and temperature drive many aspects of terrestrial Ecosystem Function. Climate change scenar- ios predict increasing precipitation variability and temper- ature, and long term experiments are required to evaluate the Ecosystem consequences of interannual climate variation, increased growing season (intra-annual) rainfall variability, and warming. We present results from an experiment ap- plying increased growing season rainfall variability and year round warming in native tallgrass prairie. During ten years of study, total growing season rainfall varied 2-fold, and we found 50-200 % interannual variability in plant growth and aboveground net primary productivity (ANPP), leaf carbon assimilation (ACO2 ), and soil CO2 efflux ( JCO2 ) despite only 40 % variation in mean volumetric soil water content (0- 15 cm, 215). Interannual variation in soil moisture was thus amplified in most measures of Ecosystem response. Dif- ferences between years in 215 explained the greatest por- tion (14-52 %) of the variation in these processes. Exper- imentally increased intra-annual season rainfall variability doubled the amplitude of intra-annual soil moisture varia- tion and reduced 215 by 15 %, causing most Ecosystem pro- cesses to decrease 8-40 % in some or all years with increased rainfall variability compared to ambient rainfall timing, sug- gesting reduced Ecosystem rainfall use efficiency. Warming treatments increased soil temperature at 5 cm depth, partic- ularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter JCO2 , and re- duced summer JCO2 and forb ANPP, suggesting that the ef- fects of warming differed in cooler versus warmer parts of the year. We conclude that (1) major Ecosystem processes in this grassland may be substantially altered by predicted changes in interannual climate variability, intra-annual rain- fall variability, and temperature, (2) interannual climate vari- ation was a larger source of variation in Ecosystem Function than intra-annual rainfall variability and warming, and (3) effects of increased growing season rainfall variability and warming were small, but ecologically important. The relative effects of these climate drivers are likely to vary for different Ecosystem processes and in wetter or drier Ecosystems.
-
dominant species maintain Ecosystem Function with non random species loss
Ecology Letters, 2003Co-Authors: Melinda D Smith, Alan K KnappAbstract:Loss of species caused by widespread stressors, such as drought and fragmentation, is likely to be non-random depending on species abundance in the community. We experimentally reduced the number of rare and uncommon plant species while independently reducing only the abundance of dominant grass species in intact, native grassland. This allowed us to simulate a non-random pattern of species loss, based on species abundances, from communities shaped by natural ecological interactions and characterized by uneven species abundance distributions. Over two growing seasons, total above-ground net primary productivity (ANPP) declined with reductions in abundance of the dominant species but was unaffected by a threefold decline in richness of less common species. In contrast, productivity of the remaining rare and uncommon species decreased with declining richness, in part due to loss of complementary interactions among these species. However, increased production of the dominant grasses offset the negative effects of species loss. We conclude that the dominant species, as controllers of Ecosystem Function, can provide short-term resistance to reductions in Ecosystem Function when species loss is nonrandom. However, the concurrent loss of complementary interactions among rare and uncommon species, the most diverse component of communities, may contribute to additional species loss and portends erosion of Ecosystem Function in the long term.
Jan Bengtsson - One of the best experts on this subject based on the ideXlab platform.
-
biodiversity disturbances Ecosystem Function and management of european forests
Forest Ecology and Management, 2000Co-Authors: Jan Bengtsson, Sven G Nilsson, Alain Franc, Paolo MenozziAbstract:Abstract We review the effects of human impact on biodiversity of European forests in the light of recent views on disturbances and succession in Ecosystems, and discuss recent ideas on how biodiversity affects Ecosystem Functions such as productivity and Ecosystem stability. With this as a background we discuss how to better manage European forests for both production and biodiversity. We argue that the next generation of forestry practices need to understand and mimic natural disturbance dynamics much better than the present ones. Of particular importance is the fact that most species in European forests have evolved in forests that were to a large extent influenced by large grazers, first by megaherbivores and later, in historic times, by domestic animals. We highlight several areas where new knowledge and management tools are urgently needed: (i) How do species survive and adapt to the natural disturbance regimes in different regions and forest types? (ii) How can new and imaginative forest management practices be devised that take natural disturbance regimes into account? (iii) How does forest biodiversity affect Ecosystem Function and stability in a changing world, in particular in the light of predicted climate changes? (iv) How are ecological processes at different levels and scales related to diversity, and how do different management practices affect biodiversity? (v) How can efficient agroforestry methods be developed to preserve biodiversity? (vi) What is the role of humans and human behaviour for sustainable management of Ecosystems?
-
which species what kind of diversity which Ecosystem Function some problems in studies of relations between biodiversity and Ecosystem Function
Applied Soil Ecology, 1998Co-Authors: Jan BengtssonAbstract:Abstract I examine a number of problems that need to be identified and accounted for when examining the relationships between diversity and Ecosystem Function. Among these are measures of diversity and complexity in Ecosystems: species richness, diversity indices, Functional groups, keystone species, connectance, etc, all of which may be difficult to relate to Ecosystem Function. Several important distinctions, when testing diversity–Function relationships empirically, are discussed: Diversity of Functional groups, diversity within Functional groups vs. total diversity; manipulating variables such as body-size distributions vs. manipulating diversity per se; effects of diversity vs. effects of biomass; and diversity–Function relations under stable vs. changing conditions or perturbations. It is argued that for the management and development of sustainable Ecosystems, it is probably more important to understand the linkages between key species or Functional groups and Ecosystem Function, rather than focusing on species diversity. This is because there are possible mechanistic relations between what species do in Ecosystems and Ecosystem Function. Diversity, being an abstract and aggregated property of the species in the context of communities and Ecosystems, lacks such direct relations to Ecosystem Functions.
