Nitrogen(N)deposition,precipitation and their interaction affect plant invasions in temperate ecosystems with limiting N and water resources,but whether and how they affect plant invasions in subtropical native commun...Nitrogen(N)deposition,precipitation and their interaction affect plant invasions in temperate ecosystems with limiting N and water resources,but whether and how they affect plant invasions in subtropical native communities with abundant N and precipitation remains unclear.We constructed in situ artificial communities with 12 common native plant species in a subtropical system and introduced four common invasive plant species and their native counterparts to these communities.We compared plant growth and establishment of introduced invasive species and native counterparts in communities exposed to ambient(CK),N addition(N+),increased precipitation(P+)and N addition plus increased precipitation(P+N+).We also investigated the density and aboveground biomass of communities under such conditions.P+alone did not enhance the performance of invasive species or native counterparts.N+enhanced only the aboveground biomass and relative density of invasive species.P+N+enhanced the growth and establishment performance of both invasive species and native counterparts.Most growth and establishment parameters of invasive species were greater than those of native counterparts under N+,P+and P+N+conditions.The density and aboveground biomass of native communities established by invasive species were significantly lower than those of native communities established by native counterparts under P+N+conditions.These results suggest that P+may magnify the effects of N+on performance of invasive species in subtropical native communities where N and water are often abundant,which may help to understand the effect of global change on plant invasion in subtropical ecosystems.展开更多
Aims The mechanism by which species richness affects variation in ecosystem functioning both within and among ecosystems remains a key question at the interface of community and ecosystem ecology.Statistical averaging...Aims The mechanism by which species richness affects variation in ecosystem functioning both within and among ecosystems remains a key question at the interface of community and ecosystem ecology.Statistical averaging(the smoothing of average system performance via consideration of additional components)and the insurance effect(reduced variation in system performance by inclusion of asynchronously varying components)predict that more diverse communities should vary less both between replicates and internally.We experimentally tested these theories in small plant assemblages.Methods We constructed plant assemblages modeled after old-field plant communities.We varied species richness,species composition and initial densities while holding functional group richness constant in replicate assemblages under glasshouse conditions.Important findings The inverse of the coefficient of variation of aboveground biomass production,a proxy measure of reliability,increased with higher diversity when examined at the level of the assemblage(i.e.among-replicate assemblages)but not at the levels of functional group or species.These stabilizing processes were weakest in low-diversity,low-density assemblages.This experiment demonstrates the utility of hierarchical analysis of ecosystem reliability at the assemblage,functional group and species level.展开更多
基金funded by the National Natural Science Foundation of China(31460165,31960282)Natural Science Foundation of Guangxi Province(2018GXNSFAA281112)Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain(19-050-6).
文摘Nitrogen(N)deposition,precipitation and their interaction affect plant invasions in temperate ecosystems with limiting N and water resources,but whether and how they affect plant invasions in subtropical native communities with abundant N and precipitation remains unclear.We constructed in situ artificial communities with 12 common native plant species in a subtropical system and introduced four common invasive plant species and their native counterparts to these communities.We compared plant growth and establishment of introduced invasive species and native counterparts in communities exposed to ambient(CK),N addition(N+),increased precipitation(P+)and N addition plus increased precipitation(P+N+).We also investigated the density and aboveground biomass of communities under such conditions.P+alone did not enhance the performance of invasive species or native counterparts.N+enhanced only the aboveground biomass and relative density of invasive species.P+N+enhanced the growth and establishment performance of both invasive species and native counterparts.Most growth and establishment parameters of invasive species were greater than those of native counterparts under N+,P+and P+N+conditions.The density and aboveground biomass of native communities established by invasive species were significantly lower than those of native communities established by native counterparts under P+N+conditions.These results suggest that P+may magnify the effects of N+on performance of invasive species in subtropical native communities where N and water are often abundant,which may help to understand the effect of global change on plant invasion in subtropical ecosystems.
基金supported by the State Key Basic Research and Development Plan(2002CB412502)the Natural Science Foundation of China(90211016)+1 种基金with additional support from Harvard Forest LTER and the Andrew Mellon Foundation.B.S.was supported by the Swiss National Science Foundation(nr.31-65224.01)the Deutsche Forschungsgemeinschaft(nr.FOR 456-WE 2618/6-1 to WW Weisser).
文摘Aims The mechanism by which species richness affects variation in ecosystem functioning both within and among ecosystems remains a key question at the interface of community and ecosystem ecology.Statistical averaging(the smoothing of average system performance via consideration of additional components)and the insurance effect(reduced variation in system performance by inclusion of asynchronously varying components)predict that more diverse communities should vary less both between replicates and internally.We experimentally tested these theories in small plant assemblages.Methods We constructed plant assemblages modeled after old-field plant communities.We varied species richness,species composition and initial densities while holding functional group richness constant in replicate assemblages under glasshouse conditions.Important findings The inverse of the coefficient of variation of aboveground biomass production,a proxy measure of reliability,increased with higher diversity when examined at the level of the assemblage(i.e.among-replicate assemblages)but not at the levels of functional group or species.These stabilizing processes were weakest in low-diversity,low-density assemblages.This experiment demonstrates the utility of hierarchical analysis of ecosystem reliability at the assemblage,functional group and species level.
