Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effect...Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effective indicators of ecological change.While previous studies have primarily focused on local community structures and species diversity during a specific season,there is a need to extend the research timeframe and explore broader spatial variations.Additionally,expanding from simple species diversity indices to more multidimensional diversity indices would provide a more comprehensive understanding of wetland health and resilience.To address these gaps,we investigated the effects of wetland degradation on bird diversity across taxonomic,phylogenetic,and functional dimensions in the Zoige Wetland,a plateau meadow wetland biodiversity hotspot.Surveys were conducted during both breeding(summer)and overwintering(winter)seasons across 20 transects in 5 sampling areas,representing 4 degradation levels(pristine,low,medium,and high).Our study recorded a total of 106 bird species from 32 families and 14 orders,revealing distinct seasonal patterns in bird community composition and diversity.Biodiversity indices were significantly higher in pristine and low-degraded wetlands,particularly benefiting waterfowl(Anseriformes,Ciconiiformes)and wading birds(Charadriiformes)in winter,when these areas provided superior food resources and habitat conditions.In contrast,medium and highly degraded wetlands supported increased numbers of terrestrial birds(Passeriformes)and raptors(Accipitriformes,Falconiformes).Seasonal differences in taxonomic,phylogenetic,and functional diversity indices highlighted the contrasting ecological roles of wetlands during breeding and overwintering periods.Furthermore,indicator species analysis revealed key species associated with specific degradation levels and seasons,providing valuable insights into wetland health.This study underscores the importance of spatiotemporal dynamics in understanding avian responses to wetland degradation.By linking seasonal patterns of bird diversity to habitat conditions,our findings contribute to conservation efforts and provide a framework for assessing wetland degradation and its ecological impacts.展开更多
Aims Species abundance distributions(SADs)are often used to verify mechanistic theories underlying community assembly.However,it is now accepted that SADs alone are not sufficient to reveal biological mechanisms.Recen...Aims Species abundance distributions(SADs)are often used to verify mechanistic theories underlying community assembly.However,it is now accepted that SADs alone are not sufficient to reveal biological mechanisms.Recent attention focuses on the relative importance of stochastic dispersal processes versus deterministic processes such as interspecific competition and environmental filtering.Here,we combine a study of the commonness and rarity of species(i.e.the SAD)with mechanistic processes underlying community composition.By comparing the occurrence frequen-cies of each and every species with its abundance,we quantify the relative contributions of common and rare species to the maintenance of community structure.Essentially,we relate the continuum between commonness and rarity with that of niches and neutrality.Methods An individual-based,spatially explicit model was used to simu-late local communities in niche spaces with the same parameters.We generated sets of assemblages from which species were elim-inated in opposing sequences:from common to rare and from rare to common,and investigated the relationship between the abundance and frequency of species.We tested the predictions of our model with empirical data from a field experiment in the environmentally homogeneous alpine meadows of the Qinghai-Tibetan plateau.Important Findings Our simulations support the widespread notion that common species maintain community structure,while rare species maintain species diversity,in both local and regional communities.Our results,both from theoretical simulations and from empirical observations,revealed positive correlations between the abundance of a particular species and its occurrence frequency.SAD curves describe a continuum between commonness and rarity.Removing species from the‘rare’end of this continuum has little effect on the similarity of communities,but remov-ing species from the‘common’end of the continuum causes significant increases in beta diversity,or species turnover,between communities.In local communities distributed in a homogenous habitat,species located at the‘common’end of the continuum should be selected by environmental filtering,with niche space partitioning governed by interspecific competition.Conversely,species located at the‘rare’end of the continuum are most likely subject to stochastic dispersal pro-cesses.Species situated at intermediate locations on this continuum are therefore determined by niche and neutral processes acting together.Our results suggest that,in homogeneous habitats,SAD curves describ-ing the common-rare continuum may also be used to describe the con-tinuum between niches and neutrality.展开更多
基金supported by the Southwest Minzu University Research Startup Funds (No.16011221038,RQD2022021)Double World-Class Project (No.CX2023010)。
文摘Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effective indicators of ecological change.While previous studies have primarily focused on local community structures and species diversity during a specific season,there is a need to extend the research timeframe and explore broader spatial variations.Additionally,expanding from simple species diversity indices to more multidimensional diversity indices would provide a more comprehensive understanding of wetland health and resilience.To address these gaps,we investigated the effects of wetland degradation on bird diversity across taxonomic,phylogenetic,and functional dimensions in the Zoige Wetland,a plateau meadow wetland biodiversity hotspot.Surveys were conducted during both breeding(summer)and overwintering(winter)seasons across 20 transects in 5 sampling areas,representing 4 degradation levels(pristine,low,medium,and high).Our study recorded a total of 106 bird species from 32 families and 14 orders,revealing distinct seasonal patterns in bird community composition and diversity.Biodiversity indices were significantly higher in pristine and low-degraded wetlands,particularly benefiting waterfowl(Anseriformes,Ciconiiformes)and wading birds(Charadriiformes)in winter,when these areas provided superior food resources and habitat conditions.In contrast,medium and highly degraded wetlands supported increased numbers of terrestrial birds(Passeriformes)and raptors(Accipitriformes,Falconiformes).Seasonal differences in taxonomic,phylogenetic,and functional diversity indices highlighted the contrasting ecological roles of wetlands during breeding and overwintering periods.Furthermore,indicator species analysis revealed key species associated with specific degradation levels and seasons,providing valuable insights into wetland health.This study underscores the importance of spatiotemporal dynamics in understanding avian responses to wetland degradation.By linking seasonal patterns of bird diversity to habitat conditions,our findings contribute to conservation efforts and provide a framework for assessing wetland degradation and its ecological impacts.
基金National Natural Science Foundation of China(31500336)the Fundamental Research Funds for the Central University(lzujbky-2015-85)Special Fund for Agro-scientific Research in the Public Interest(201203006).
文摘Aims Species abundance distributions(SADs)are often used to verify mechanistic theories underlying community assembly.However,it is now accepted that SADs alone are not sufficient to reveal biological mechanisms.Recent attention focuses on the relative importance of stochastic dispersal processes versus deterministic processes such as interspecific competition and environmental filtering.Here,we combine a study of the commonness and rarity of species(i.e.the SAD)with mechanistic processes underlying community composition.By comparing the occurrence frequen-cies of each and every species with its abundance,we quantify the relative contributions of common and rare species to the maintenance of community structure.Essentially,we relate the continuum between commonness and rarity with that of niches and neutrality.Methods An individual-based,spatially explicit model was used to simu-late local communities in niche spaces with the same parameters.We generated sets of assemblages from which species were elim-inated in opposing sequences:from common to rare and from rare to common,and investigated the relationship between the abundance and frequency of species.We tested the predictions of our model with empirical data from a field experiment in the environmentally homogeneous alpine meadows of the Qinghai-Tibetan plateau.Important Findings Our simulations support the widespread notion that common species maintain community structure,while rare species maintain species diversity,in both local and regional communities.Our results,both from theoretical simulations and from empirical observations,revealed positive correlations between the abundance of a particular species and its occurrence frequency.SAD curves describe a continuum between commonness and rarity.Removing species from the‘rare’end of this continuum has little effect on the similarity of communities,but remov-ing species from the‘common’end of the continuum causes significant increases in beta diversity,or species turnover,between communities.In local communities distributed in a homogenous habitat,species located at the‘common’end of the continuum should be selected by environmental filtering,with niche space partitioning governed by interspecific competition.Conversely,species located at the‘rare’end of the continuum are most likely subject to stochastic dispersal pro-cesses.Species situated at intermediate locations on this continuum are therefore determined by niche and neutral processes acting together.Our results suggest that,in homogeneous habitats,SAD curves describ-ing the common-rare continuum may also be used to describe the con-tinuum between niches and neutrality.
