Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings we...Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings were both feasible and functional for early model generations, in light of the pace at which our knowledge of functional ecology, ecosystem demographics, and vegetation-climate feedbacks has advanced and the ever growing demand for enhanced model performance, these groupings have become antiquated and are identified as a key source of model uncertainty. The newest wave of model development is centered on shifting the vegetation paradigm away from plant functional types(PFTs)and towards flexible trait-based representations. These models seek to improve errors in ecosystem fluxes that result from information loss due to over-aggregation of dissimilar species into the same functional class. We advocate the importance of the inclusion of plant hydraulic trait representation within the new paradigm through a framework of the whole-plant hydraulic strategy. Plant hydraulic strategy is known to play a critical role in the regulation of stomatal conductance and thus transpiration and latent heat flux. It is typical that coexisting plants employ opposing hydraulic strategies, and therefore have disparate patterns of water acquisition and use. Hydraulic traits are deterministic of drought resilience, response to disturbance, and other demographic processes. The addition of plant hydraulic properties in models may not only improve the simulation of carbon and water fluxes but also vegetation population distributions.展开更多
Understanding the response of the phytoplankton community to climate change is essential for reservoir management.We analyzed a long-term data series(2009–2020)on the phytoplankton community in a large mesotrophic re...Understanding the response of the phytoplankton community to climate change is essential for reservoir management.We analyzed a long-term data series(2009–2020)on the phytoplankton community in a large mesotrophic reservoir in the wet season to investigate the impacts of temperature and precipitation increases caused by climate change on the functioning and trait composition of the phytoplankton community.Over the last twelve years,the 3-month accumulative precipitation increased from 291.03 mm to 590.91 mm,and the surface water temperature increased from 25.06℃to 26.49℃in wet season,respectively.These changes caused a higher water level,stronger thermal stratification and lower nitrogen concentration in Daxi Reservoir.The dynamic equilibrium model indicated that the increased precipitation and water temperature-related environmental changes would result in a more diverse and productive phytoplankton community.The effects of increasing water temperature and precipitation on the niche complementarity and selection effects within the phytoplankton community were analyzed using structural equation model by means of the functional divergence index and functional evenness index,respectively,elucidating the reasons for the increase in cyanobacteria in the absence of a significant increase in nutrient levels.Based on these results,it is advisable that more stringent phosphorus control standards might be conducted to reduce the risks of cyanobacteria proliferation in the context of global warming.展开更多
Forests undergoing ecological succession following abandonment from agricultural use(i.e.,old fields)are ubiquitous in temperate regions of the U.S.and Europe.Ecological succession in old fields involves changes in ve...Forests undergoing ecological succession following abandonment from agricultural use(i.e.,old fields)are ubiquitous in temperate regions of the U.S.and Europe.Ecological succession in old fields involves changes in vegetation composition influenced by factors such as land-use history,soil conditions,and dispersal limitations.Species’behavioral,morphological,physiological and life-history attributes influence the outcomes of environmental and biotic filters on distribution and abundance.However,many studies have focused on aboveground attributes,while less attention has been placed on belowground species characteristics that influence community assembly and function.In this study,we used a trait-based approach to examine how aboveground plant composition and distribution vary with plant root functional traits(e.g.,mycorrhizal association)that mediate access for nutrients such as nitrogen(N)and phosphorous(P).We inventoried every tree stem(n=11,551)in a 10-ha forested area containing old-field and historical forests and matched every species with root functional traits(n=33)from established databases.We found that land-use history influences community composition and distribution in old-field forests,which also varied with belowground root functional traits.Community composition in old-field forests,which were dominated by Acer saccharum and non-native species,were largely associated with arbuscular mycorrhizae(AM)and higher root nutrient concentrations.On the other hand,community composition in historical forests–largely dominated by Tsuga canadensis–were associated with ectomycorrhiza(EcM)and more variation of root length and depth.These results suggest that changes in aboveground communities have implications for belowground ecosystem services(e.g.,nutrient cycling)which are important to forest ecosystem development.Trait-based approaches can elucidate mechanisms of community assembly,and understanding how traits influence species coexistence and interactions can inform management decisions related to biodiversity conservation and restoration efforts in disturbed or altered forests.展开更多
Aims community assembly links plant traits to particular environmental conditions.Numerous studies have adopted a trait-based approach to understand both community assembly processes and changes in plant functional tr...Aims community assembly links plant traits to particular environmental conditions.Numerous studies have adopted a trait-based approach to understand both community assembly processes and changes in plant functional traits along environmental gradients.In most cases these are long-established,natural or semi-natural environments.However,increasingly human activity has created,and continues to create,a range of new environmental conditions,and under-standing community assembly in these‘novel environments’will be increasingly important.Methods Built in 2006,the three Gorges Dam,largest hydraulic project in china,created a new riparian area of 384 km^(2),with massively al-tered hydrology.this large,newly created ecosystem is an ideal platform for understanding community assembly in a novel environment.We sampled environment variables and plant communities within 103 plots located in both the reservoir riparian zone(RRZ)and adjacent non-flooded and semi-natural upland(Upland)at the three Gorges Reservoir Area.We measured six traits from 168 plant species in order to calculate community-level distribution of trait values.We expected that the altered hydrology in RRZ would have a profound effect on the community assembly process for the local plants.Important Findingsconsistent with previous work on community assembly,the dis-tribution of trait values(range,variance,kurtosis and the standard deviation of the distribution neighbor distances)within all plots was significantly lower than those from random distributions,indicat-ing that both habitat filtering and limiting similarity simultaneously shaped the distributions of traits and the assembly of plant commu-nities.considering the newly created RRZ relative to nearby sites,community assembly was different in two main ways.First,there was a large shift in the mean trait values.compared to Upland commu-nities,plant communities in the RRZ had higher mean specific leaf area(SLA),higher nitrogen per unit leaf mass(Nmass),and lower max-imum height(MH).Second,in the RRZ compared to the Upland,for the percentage of individual plots whose characteristic of trait values was lower than null distributions,the reductions in the community-level range for SLA,Nmass,nitrogen per unit leaf area(Narea)and phos-phorus per unit leaf area(Parea)were much larger,suggesting that the habitat filter in this newly created riparian zone was much stronger compared to longer established semi-natural upland vegetation.this stronger filter,and the restriction to a subset of plants with very similar trait values,has implications for predicting riparian ecosystems’responses to the hydrological alterations and further understanding for human’s effect on plant diversity and plant floras.展开更多
Wetland reclamation disrupts original biogeomorphic processes,making passive restoration after agricultural abandonment a key near‒natural solution.Soil organic carbon(TSOC),total nitrogen(TSN),and total phosphorus(TS...Wetland reclamation disrupts original biogeomorphic processes,making passive restoration after agricultural abandonment a key near‒natural solution.Soil organic carbon(TSOC),total nitrogen(TSN),and total phosphorus(TSP)storages serve as critical indicators of ecological restoration outcomes,closely linked to plant community succession and functional strategies,however,their drivers and influencing pathways remain unclear.This study examined soil functions(TSOC,TSN,and TSP),plant communities,and functional traits in passively restored freshwater wetlands following agricultural abandonment on China’s Sanjiang Plain.Results revealed that TSOC and TSN peaked at 14‒and 17‒year post‒restoration,respectively,then stabilized,while TSP initially decreased before increasing.With extended restoration duration,plant communities showed increased height,coverage and biomass but decreased density and diversity,while functional traits transitioned from acquisitive to conservative strategies.Variance partitioning analysis revealed that soil function dynamics were primarily governed by plant community and functional trait interactions.Random forest models identified key drivers,while structural equation modeling delineated both direct effects of restoration duration and indirect pathways mediated by plant attributes.Specifically,synergistic declines in specific leaf area(SLA)and plant density enhanced TSOC accumulation.Coordinated reductions in SLA and stem phosphorus content(SPC)increased aboveground biomass(AGB),thereby elevating TSN but depleting TSP.A trade‒off between leaf phosphorus content(LPC)and root‒to‒shoot ratio(RSR)further modulated TSN dynamics.These findings demonstrate that passive wetland restoration facilitates soil function stabilization,with plant functional traits and community characteristics playing synergistic effects.This mechanistic understanding provides a scientific framework for optimizing restoration strategies.展开更多
基金Funding for this study was provided by the U.S. National Science Foundation Hydrological Science grant 1521238the U.S. Department of Energy's Office of Science Office of Biological and Environmental Research,Terrestrial Ecosystem Sciences Program Award No. DE-SC0007041Ameriflux Management Project Core Site Agreement No. 7096915
文摘Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings were both feasible and functional for early model generations, in light of the pace at which our knowledge of functional ecology, ecosystem demographics, and vegetation-climate feedbacks has advanced and the ever growing demand for enhanced model performance, these groupings have become antiquated and are identified as a key source of model uncertainty. The newest wave of model development is centered on shifting the vegetation paradigm away from plant functional types(PFTs)and towards flexible trait-based representations. These models seek to improve errors in ecosystem fluxes that result from information loss due to over-aggregation of dissimilar species into the same functional class. We advocate the importance of the inclusion of plant hydraulic trait representation within the new paradigm through a framework of the whole-plant hydraulic strategy. Plant hydraulic strategy is known to play a critical role in the regulation of stomatal conductance and thus transpiration and latent heat flux. It is typical that coexisting plants employ opposing hydraulic strategies, and therefore have disparate patterns of water acquisition and use. Hydraulic traits are deterministic of drought resilience, response to disturbance, and other demographic processes. The addition of plant hydraulic properties in models may not only improve the simulation of carbon and water fluxes but also vegetation population distributions.
基金Supported by the National Natural Science Foundation of China(Nos.U22A20616,32071573)。
文摘Understanding the response of the phytoplankton community to climate change is essential for reservoir management.We analyzed a long-term data series(2009–2020)on the phytoplankton community in a large mesotrophic reservoir in the wet season to investigate the impacts of temperature and precipitation increases caused by climate change on the functioning and trait composition of the phytoplankton community.Over the last twelve years,the 3-month accumulative precipitation increased from 291.03 mm to 590.91 mm,and the surface water temperature increased from 25.06℃to 26.49℃in wet season,respectively.These changes caused a higher water level,stronger thermal stratification and lower nitrogen concentration in Daxi Reservoir.The dynamic equilibrium model indicated that the increased precipitation and water temperature-related environmental changes would result in a more diverse and productive phytoplankton community.The effects of increasing water temperature and precipitation on the niche complementarity and selection effects within the phytoplankton community were analyzed using structural equation model by means of the functional divergence index and functional evenness index,respectively,elucidating the reasons for the increase in cyanobacteria in the absence of a significant increase in nutrient levels.Based on these results,it is advisable that more stringent phosphorus control standards might be conducted to reduce the risks of cyanobacteria proliferation in the context of global warming.
基金supported financially by the Dartmouth College Guarini Dean's Postdoctoral Fellowship Program
文摘Forests undergoing ecological succession following abandonment from agricultural use(i.e.,old fields)are ubiquitous in temperate regions of the U.S.and Europe.Ecological succession in old fields involves changes in vegetation composition influenced by factors such as land-use history,soil conditions,and dispersal limitations.Species’behavioral,morphological,physiological and life-history attributes influence the outcomes of environmental and biotic filters on distribution and abundance.However,many studies have focused on aboveground attributes,while less attention has been placed on belowground species characteristics that influence community assembly and function.In this study,we used a trait-based approach to examine how aboveground plant composition and distribution vary with plant root functional traits(e.g.,mycorrhizal association)that mediate access for nutrients such as nitrogen(N)and phosphorous(P).We inventoried every tree stem(n=11,551)in a 10-ha forested area containing old-field and historical forests and matched every species with root functional traits(n=33)from established databases.We found that land-use history influences community composition and distribution in old-field forests,which also varied with belowground root functional traits.Community composition in old-field forests,which were dominated by Acer saccharum and non-native species,were largely associated with arbuscular mycorrhizae(AM)and higher root nutrient concentrations.On the other hand,community composition in historical forests–largely dominated by Tsuga canadensis–were associated with ectomycorrhiza(EcM)and more variation of root length and depth.These results suggest that changes in aboveground communities have implications for belowground ecosystem services(e.g.,nutrient cycling)which are important to forest ecosystem development.Trait-based approaches can elucidate mechanisms of community assembly,and understanding how traits influence species coexistence and interactions can inform management decisions related to biodiversity conservation and restoration efforts in disturbed or altered forests.
文摘Aims community assembly links plant traits to particular environmental conditions.Numerous studies have adopted a trait-based approach to understand both community assembly processes and changes in plant functional traits along environmental gradients.In most cases these are long-established,natural or semi-natural environments.However,increasingly human activity has created,and continues to create,a range of new environmental conditions,and under-standing community assembly in these‘novel environments’will be increasingly important.Methods Built in 2006,the three Gorges Dam,largest hydraulic project in china,created a new riparian area of 384 km^(2),with massively al-tered hydrology.this large,newly created ecosystem is an ideal platform for understanding community assembly in a novel environment.We sampled environment variables and plant communities within 103 plots located in both the reservoir riparian zone(RRZ)and adjacent non-flooded and semi-natural upland(Upland)at the three Gorges Reservoir Area.We measured six traits from 168 plant species in order to calculate community-level distribution of trait values.We expected that the altered hydrology in RRZ would have a profound effect on the community assembly process for the local plants.Important Findingsconsistent with previous work on community assembly,the dis-tribution of trait values(range,variance,kurtosis and the standard deviation of the distribution neighbor distances)within all plots was significantly lower than those from random distributions,indicat-ing that both habitat filtering and limiting similarity simultaneously shaped the distributions of traits and the assembly of plant commu-nities.considering the newly created RRZ relative to nearby sites,community assembly was different in two main ways.First,there was a large shift in the mean trait values.compared to Upland commu-nities,plant communities in the RRZ had higher mean specific leaf area(SLA),higher nitrogen per unit leaf mass(Nmass),and lower max-imum height(MH).Second,in the RRZ compared to the Upland,for the percentage of individual plots whose characteristic of trait values was lower than null distributions,the reductions in the community-level range for SLA,Nmass,nitrogen per unit leaf area(Narea)and phos-phorus per unit leaf area(Parea)were much larger,suggesting that the habitat filter in this newly created riparian zone was much stronger compared to longer established semi-natural upland vegetation.this stronger filter,and the restriction to a subset of plants with very similar trait values,has implications for predicting riparian ecosystems’responses to the hydrological alterations and further understanding for human’s effect on plant diversity and plant floras.
基金supported by the National Natural Science Foundation of China(4187110242471066)+2 种基金the Science and Technology Development Program of Jilin Province of China(20230203003SF20240602026RC)the Major Scientific and Technological Project of Jilin Province of China(20230303005SF)。
文摘Wetland reclamation disrupts original biogeomorphic processes,making passive restoration after agricultural abandonment a key near‒natural solution.Soil organic carbon(TSOC),total nitrogen(TSN),and total phosphorus(TSP)storages serve as critical indicators of ecological restoration outcomes,closely linked to plant community succession and functional strategies,however,their drivers and influencing pathways remain unclear.This study examined soil functions(TSOC,TSN,and TSP),plant communities,and functional traits in passively restored freshwater wetlands following agricultural abandonment on China’s Sanjiang Plain.Results revealed that TSOC and TSN peaked at 14‒and 17‒year post‒restoration,respectively,then stabilized,while TSP initially decreased before increasing.With extended restoration duration,plant communities showed increased height,coverage and biomass but decreased density and diversity,while functional traits transitioned from acquisitive to conservative strategies.Variance partitioning analysis revealed that soil function dynamics were primarily governed by plant community and functional trait interactions.Random forest models identified key drivers,while structural equation modeling delineated both direct effects of restoration duration and indirect pathways mediated by plant attributes.Specifically,synergistic declines in specific leaf area(SLA)and plant density enhanced TSOC accumulation.Coordinated reductions in SLA and stem phosphorus content(SPC)increased aboveground biomass(AGB),thereby elevating TSN but depleting TSP.A trade‒off between leaf phosphorus content(LPC)and root‒to‒shoot ratio(RSR)further modulated TSN dynamics.These findings demonstrate that passive wetland restoration facilitates soil function stabilization,with plant functional traits and community characteristics playing synergistic effects.This mechanistic understanding provides a scientific framework for optimizing restoration strategies.
