标题： 环境随机性对中性群落物种丰富度的影响 显示英文标题

标题： The effect of environmental stochasticity on species richness in neutral communities

摘要： 环境随机性被认为是导致不稳定的一个因素，它会增加种群的丰度波动和灭绝率。 然而，由于存储效应，物种对环境变化的不同反应可能会使群落的稳定性受益。 本文使用最近提出的生物多样性时间平均中性模型的元群落版本，对该两种相互矛盾的趋势进行了系统而全面的讨论，该模型包含了环境随机性和种群噪声，并允许灭绝和物种形成。 我们表明，将种群噪声纳入模型对于其适用性至关重要，在适应性变化相对较弱时，能够产生系统的现实行为。 当环境变化的相关时间增加时，物种丰富度对环境随机性强度的依赖关系会发生符号变化。 这一转变标志着存储效应不再能够稳定群落的临界点。 显示英文摘要

摘要： Environmental stochasticity is known to be a destabilizing factor, increasing abundance fluctuations and extinction rates of populations. However, the stability of a community may benefit from the differential response of species to environmental variations due to the storage effect. This paper provides a systematic and comprehensive discussion of these two contradicting tendencies, using the metacommunity version of the recently proposed time-average neutral model of biodiversity which incorporates environmental stochasticity and demographic noise and allows for extinction and speciation. We show that the incorporation of demographic noise into the model is essential to its applicability, yielding realistic behavior of the system when fitness variations are relatively weak. The dependence of species richness on the strength of environmental stochasticity changes sign when the correlation time of the environmental variations increases. This transition marks the point at which the storage effect no longer succeeds in stabilizing the community.