Mechanisms linked to demographic, biogeographic, and food-web processes thought to underpin community stability could be affected by habitat size, but the effects of habitat size on community stability remain relatively unknown. We investigated whether those habitat-size-dependent properties influenced community instability and vulnerability to perturbations caused by disturbance. This is particularly important given that human exploitation is contracting ecosystems, and abiotic perturbations are becoming more severe and frequent. We used a perturbation experiment in which 10 streams, spanning three orders of magnitude in habitat size, were subjected to simulated bed movement akin to a major flood disturbance event. We measured the resistance, resilience, and variability of basal resources, and population and community-level responses across the stream habitat-size gradient immediately before, and at 0.5, 5, 10, 20, and 40 d post-disturbance. Resistance to disturbance consistently increased with stream size in all response variables. In contrast, resilience was significantly higher in smaller streams for some response variables. However, this higher resilience of small ecosystems was insufficient to compensate for their lower resistance, and communities of smaller streams were thus more variable over time than those of larger streams. Compensatory dynamics of populations, especially for predators, stabilized some aspects of communities, but these mechanisms were unrelated to habitat size. Together, our results provide compelling evidence for the links between habitat size and community stability, and should motivate ecologists and managers to consider how changes in the size of habitats will alter the vulnerability of ecosystems to perturbations caused by environmental disturbance.

中文翻译：

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栖息地大小影响社区稳定性

与人口、生物地理学和食物网过程相关的被认为支持群落稳定性的机制可能会受到栖息地大小的影响，但栖息地大小对群落稳定性的影响仍然相对未知。我们调查了这些依赖于栖息地大小的特性是否会影响群落的不稳定性和对干扰引起的扰动的脆弱性。鉴于人类开发正在收缩生态系统，并且非生物扰动变得越来越严重和频繁，这一点尤其重要。我们使用了一个扰动实验，其中 10 条溪流，跨越三个数量级的栖息地大小，受到类似于主要洪水扰动事件的模拟床运动。我们测量了基础资源的抵抗力、弹性和可变性，在扰动前和扰动后 0.5、5、10、20 和 40 天，整个河流栖息地大小梯度的人口和社区层面的响应。在所有响应变量中，对干扰的抵抗力随着流的大小而不断增加。相比之下，对于某些响应变量，较小流中的弹性明显更高。然而，小型生态系统的这种较高的恢复力不足以弥补它们较低的抵抗力，因此较小河流的群落随着时间的推移比较大河流的群落变化更大。种群的补偿动态，尤其是捕食者，稳定了群落的某些方面，但这些机制与栖息地大小无关。总之，我们的结果为栖息地大小和社区稳定性之间的联系提供了令人信服的证据，