Positive interactions can produce species-rich communities and increase species turnover through time  

作　　者：Youshi Wang M.D.Farnon Ellwood Fernando TMaestre Zhiyong Yang Gang Wang Chengjin Chu 

机构地区：[1]MOE Key Laboratory of Western China’s Environmental Systems,Research School of Arid Environment and Climate Change,Lanzhou University,Lanzhou 730000,China [2]Department of Zoology,University of Cambridge,Downing Street,Cambridge CB23EJ,UK [3]Area de Biodiversidad y Conservacion,Departamento de Biología y Geología,ESCET,Universidad Rey Juan Carlos,c/Tulipan s/n,28933 Mostoles,Spain [4]State Key Laboratory of Grassland Agro-ecosystems,School of Life Sciences,Lanzhou University,Lanzhou 730000,China

出　　处：《Journal of Plant Ecology》2012年第4期417-421,共5页植物生态学报（英文版）

基　　金：National Natural Science Foundation of China(31000199,30970543,30770360,41021091);the Fundamental Research Funds for the Central Universities(lzujbky-2012-133,lzujbky-2009-88,lzujbky-2010-49);the Youth Innovation Research Fund for Interdisciplince of Lanzhou University(LZUJC200915);the Department of Zoology,University of Cambridge(to M.D.F.E.);the European Research Council(the European Community’s Seventh Framework Programme FP7/2007-2013 to F.T.M./ERC grant agreement no.242658[BIOCOM]).

摘　　要：Aims The process of facilitation,where a species increases the survival,growth,and fitness of another species,is becoming increasingly recognized as a critical factor in shaping the structure of plant communities.This process is particularly important in stressful environments.Yet few studies have attempted to incorporate positive interactions into community ecological theories such as the neutral theory of biodiversity.Here,we use an equalizing trade-off model as a foundation to study the potential impact of facilitation on species richness and community temporal turnover.Methods Based on a spatially explicit birth–death trade-off model,we assume that the occurrence of facilitation is dependent on the presence of interspecific neighbours.We further propose that the realized birth rate for a given individual subject to facilitation is proportional to the number of interspecific neighbours within its neighbourhood.Thus,in our model,the individuals of rare species will benefit more from the existence of heterospecific individuals than common species.Important Findings As the facilitative coefficient increased,the species richness for simulated communities at the dynamically stochastic equilibrium was also increasing.Simulations also demonstrated that facilitation could increase the replacement of species through time:communities with facilitation become more dissimilar(i.e.have smaller Bray–Curtis similarity values)than communities without or with a lower degree of facilitation after the same time interval.Facilitation from interspecific neighbours on rare species increased their population sizes and consequently made them less prone to extinction,thus enhancing species richness.Meanwhile,in a saturated community,with the increase of species richness,mean population size of entire communities decreased,making species more prone to extinction on average,and thus increased the community temporal turnover.Our results suggest that future experimental work on the effect of facilitation on community-level properties

关 键 词：Bray–Curtis similarity index positive interactions species coexistence species temporal turnover 

分 类 号：O17[理学—数学]