Drought mediates the importance of stochastic community assembly
Drought mediates the importance of stochastic community assembly
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DOI：
10.1073/pnas.0704350104
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发表时间：
2007-10-30
影响因子：
11.1
通讯作者：
Chase, Jonathan M.
中科院分区：
文献类型：
--
作者：
Chase, Jonathan M.
从历史上看，一个地方的生物多样性和物种组成被认为主要受确定性因素的影响。在这种情况下，物种的生态位对环境条件和种间相互作用产生了不同的反应，这些反应联合收割机决定了当地的生物多样性和物种组成。最近，中性理论的支持者已经把溢价放在随机因素，如出生，死亡，殖民和灭绝（称为“生态漂移”）如何影响多样性和物种组成的地方独立于他们的小生境。在这里，我发展的假设，随机生态漂移和/或优先级的影响的相对重要性取决于在这些栖息地的生态过滤器的严酷性。我建立了长期的实验池塘，以探讨社区组装历史和干旱的社区组成相似性的模式，否则在他们的环境条件相似的池塘之间的相对重要性。我显示相当大的网站到网站的变化，在没有干旱的情况下，可能会导致随机生态漂移和优先级的影响相结合的池塘群落组成。然而，在经历过干旱的池塘中，我发现群落之间的相似性要高得多，这可能是由于生态位选择从无法忍受这种环境恶劣的区域池中过滤出物种。这些结果表明，在不同的空间尺度上研究生物多样性的格局时，了解群落组装过程的关键作用。
Historically, the biodiversity and composition of species in a locality was thought to be influenced primarily by deterministic factors. In such cases, species' niches create differential responses to environmental conditions and interspecific interactions, which combine to determine that locality's biodiversity and species composition. More recently, proponents of the neutral theory have placed a premium on how stochastic factors, such as birth, death, colonization, and extinction (termed "ecological drift") influence diversity and species composition in a locality independent of their niches. Here, I develop the hypothesis that the relative importance of stochastic ecological drift and/or priority effects depend on the harshness of the ecological filter in those habitats. I established long-term experimental ponds to explore the relative importance of community assembly history and drought on patterns of community compositional similarity among ponds that were otherwise similar in their environmental conditions. I show considerable site-to-site variation in pond community composition in the absence of drought that likely resulted from a combination of stochastic ecological drift and priority effects. However, in ponds that experienced drought, I found much higher similarity among communities that likely resulted from niche-selection filtering out species from the regional pool that could not tolerate such environmental harshness. These results implicate the critical role for understanding the processes of community assembly when examining patterns of biodiversity at different spatial scales.