Coexistence of nearly neutral species  

作　　者：Fangliang He Da-Yong Zhang Kui Lin 

机构地区：[1]Department of Renewable Resources,University of Alberta,Edmonton,Alberta,Canada T6G 2H1 [2]SYSU-Alberta Joint Lab for Biodiversity Conservation,State Key Laboratory of Biocontrol,Sun Yat-sen University,Guangzhou 510275,China [3]State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory of Biodiversity Sciences and Ecological Engineering,Beijing Normal University,Beijing,100875 China

出　　处：《Journal of Plant Ecology》2012年第1期72-81,共10页植物生态学报（英文版）

基　　金：National Natural Science Foundation of China(D.Y.Z.and K.L.);Ministry of Science and Technology of China(D.Y.Z.and K.L.);Geomatics for Informed Decisions Network of Canada(F.H.);Natural Sciences and Engineering Research Council of Canada(F.L.);University of Alberta International(the China-UofA Joint Research Lab program).

摘　　要：Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of relaxing the assumption of strict neutrality to allow for empirically observed variation in vital rates and the‘problem of time’—empirically measured coexistence times are much shorter than the prediction of the strictly neutral drift model.Here,we develop a nearly neutral model that allows for differential birth and death rates of species.This model provides an approach to study species coexistence away from strict neutrality.Methods Based on Moran’s neutral model,which assumes all species in a community have the same competitive ability and have identical birth and death rates,we developed a model that includes birth–death trade-off but excludes speciation.This model describes a wide range of asymmetry from strictly neutral to nearly neutral to far from neutral and is useful for analyzing the effect of drift on species coexistence.Specifically,we analyzed the effects of the birth–death trade-off on the time and probability of species coexistence and quantified the loss of biodiversity(as measured by Simpson’s diversity)due to drift by varying species birth and death rates.Important Findings We found(i)a birth–death trade-off operating as an equalizing force driven by demographic stochasticity promotes the coexistence of nearly neutral species.Species near demographic trade-offs(i.e.fitness equivalence)can coexist even longer than that predicted by the strictly neutral model;(ii)the effect of birth rates on species coexistence is very similar to that of death rates,but their compensatory effects are not completely symmetric;(iii)ecological drift over time produces a march to fixation.Trade-off-based neutral communities lose diversity more slowly than the strictly neutral community,while non-neutral communities lose diversity much more rapidly;and(iv)nearly neutral systems have substan

关 键 词：birth rate ecological drift death rate demographic trade-off nearly neutral theory probability of extinction time of coexistence 

分 类 号：O17[理学—数学]