Population synchrony and stability in environmentally forced metacommunities
Population synchrony and stability in environmentally forced metacommunities
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DOI：
10.1111/j.1600-0706.2012.20936.x
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发表时间：
2013-08
期刊：
影响因子：
3.4
通讯作者：
Christopher F. Steiner;R. D. Stockwell;V. Kalaimani;Zakaria Aqel
中科院分区：
文献类型：
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作者：
Christopher F. Steiner;R. D. Stockwell;V. Kalaimani;Zakaria Aqel
简单的集合种群模型的一般预测是，空间同步强迫可以在空间上同步种群动态并破坏集合种群的稳定。相反，空间异步强迫预计会降低种群同步性并促进时间稳定性和种群持久性，特别是在存在扩散的情况下。直到最近，研究才开始通过实验来解决这些预测。此外，很少有研究通过实验检验这些过程如何在竞争社区的背景下运作。当放置在具有多个竞争消费者的元社区环境中时，稳定过程可能会继续运行，但仅限于低到中等的分散水平。高扩散率可能会扭转这些预测并导致不稳定。我们在受控条件下使用由三种竞争的浮游动物物种组成的实验水生系统对此进行了测试。元群落以空间同步或异步 pH 扰动的形式经历了不同程度的扩散和环境强迫。我们发现，根据种群动态在空间上同步的程度，分散会对种群稳定性产生相反的影响。同步强迫或无强迫下的扩散对所有三种浮游动物物种的空间种群同步性具有中性或积极影响。在这些处理中，扩散降低了三个物种中的两个在当地和集合种群水平上的种群稳定性。相比之下，无论分散程度如何，异步变化的环境相对于非强迫系统都会降低种群同步性。在这些处理中，分散不是通过减少种群同步性而是通过提高种群最小值和丰度的空间平均来增强种群的时间稳定性和持久性。异步强迫下的高扩散率减少了一种物种的丰度，这与区域竞争的加剧和一般的元群落理论相一致。然而，没有观察到对其稳定性或持久性的影响。我们的工作强调了不同环境中扩散对种群动态的上下文相关影响。
A general prediction from simple metapopulation models is that spatially synchronized forcing can spatially synchronize population dynamics and destabilize metapopulations. In contrast, spatially asynchronous forcing is predicted to decrease population synchrony and promote temporal stability and population persistence, especially in the presence of dispersal. Only recently have studies begun to experimentally address these predictions. Moreover, few studies have experimentally examined how such processes operate in the context of competition communities. Stabilizing processes may continue to operate when placed within a metacommunity context with multiple competing consumers but only at low to intermediate levels of dispersal. High dispersal rates can reverse these predictions and lead to destabilization. We tested this under controlled conditions using an experimental aquatic system composed of three competing species of zooplankton. Metacommunities experienced different levels of dispersal and environmental forcing in the form of spatially synchronous or asynchronous pH perturbations. We found support that dispersal can have contrasting effects on population stability depending on the degree to which population dynamics were synchronized in space. Dispersal under synchronous forcing or no forcing had either neutral of positive effects on spatial population synchrony of all three zooplankton species. In these treatments, dispersal reduced population stability at the local and metapopulation levels for two of three species. In contrast, asynchronously varying environments reduced population synchrony relative to unforced systems, regardless of dispersal level. In these treatments, dispersal enhanced temporal stability and persistence of populations not by reducing population synchrony but by enhancing population minima and spatial averaging of abundances. High dispersal rates under asynchronous forcing reduced the abundance of one species, consistent with increasing regional competition and general metacommunity theory. However, no effects on its stability or persistence were observed. Our work highlights the context-dependent effects of dispersal on population dynamics in varying environments.