Recent studies have found considerable trait variations within species. The effect of such intra-specific trait variability (ITV) on the stability, coexistence and diversity of ecological communities received considerable attention and in many models it was shown to impede coexistence and decrease species diversity. Here we present a numerical study of the effect of genetically inherited ITV on species persistence and diversity in a temporally uctuating environment. Two mechanisms are identified. First, ITV buffers populations against varying environmental conditions (portfolio effect) and reduces variation in abundances. Second, the interplay between ITV and environmental variations tends to increase the mean fitness of diverse populations. The first mechanism promotes persistence and tends to increase species richness, while the second reduces the chance of a rare species population (which is usually homogeneous) to invade, thus decreasing species richness. We show that for large communities the portfolio effect is dominant, leading to ITV promoting species persistence and richness.

中文翻译：

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波动环境中的种内变异：对物种多样性的影响机制

最近的研究发现物种内有相当大的性状变异。这种种内性状变异 (ITV) 对生态群落稳定性、共存和多样性的影响受到了相当多的关注，在许多模型中，它被证明会阻碍共存并减少物种多样性。在这里，我们提出了一项关于遗传 ITV 对时间波动环境中物种持久性和多样性影响的数值研究。确定了两种机制。首先，ITV 根据不同的环境条件（组合效应）缓冲种群并减少丰度的变化。其次，ITV 和环境变化之间的相互作用往往会增加不同人群的平均适应度。第一种机制促进持久性并倾向于增加物种丰富度，而第二个减少了稀有物种种群（通常是同质的）入侵的机会，从而降低了物种丰富度。我们表明，对于大型社区，投资组合效应占主导地位，导致 ITV 促进物种的持久性和丰富性。