Nicholas School of the Environment, Department of Biology, Duke University, Durham, NC 27708, USA.
Science. 2010 Feb 26;327(5969):1129-32. doi: 10.1126/science.1183506.
In the past, explanations for high species diversity have been sought at the species level. Theory shows that coexistence requires substantial differences between species, but species-level data rarely provide evidence for such differences. Using data from forests in the southeastern United States, I show here that variation evident at the individual level provides for coexistence of large numbers of competitors. Variation among individuals within populations allows species to differ in their distributions of responses to the environment, despite the fact that the populations to which they belong do not differ, on average. Results are consistent with theory predicting that coexistence depends on competition being stronger within than between species, shown here by analysis of individual-level responses to environmental fluctuation.
过去，人们一直在物种层面探寻物种多样性高的原因。理论表明，共存需要物种间存在实质性差异，但物种层面的数据很少能提供此类差异的证据。本文利用美国东南部森林的数据表明，个体层面的变异为大量竞争者的共存提供了条件。尽管所属种群在平均水平上没有差异，但种群内个体之间的差异使得它们对环境的反应分布有所不同。结果与理论一致，即共存取决于种内竞争强于种间竞争，这一点通过对个体对环境波动的反应的分析得到了证实。
