Department of Ecology and Genetics/Limnology, Uppsala University, Uppsala, Sweden.
ISME J. 2012 Jun;6(6):1107-14. doi: 10.1038/ismej.2011.177. Epub 2011 Dec 8.
The turnover of community composition across space, β-diversity, is influenced by different assembly mechanisms, which place varying weight on local habitat factors, such as environmental conditions and species interactions, and regional factors such as dispersal and history. Several assembly mechanisms may function simultaneously; however, little is known about how their importance changes over time and why. Here, we implemented a field survey where we sampled a bacterial metacommunity consisting of 17 rock pools located at the Swedish Baltic Sea coast at 11 occasions during 1 year. We determined to which extent communities were structured by different assembly mechanisms using variation partitioning and studied changes in β-diversity across environmental gradients over time. β-Diversity was highest at times of high overall productivity and environmental heterogeneity in the metacommunity, at least partly due to species sorting, that is, selection of taxa by the prevailing environmental conditions. In contrast, dispersal-driven assembly mechanisms were primarily detected at times when β-diversity was relatively low. There were no indications for strong and persistent differences in community composition or β-diversity between permanent and temporary pools, indicating that the physical disturbance regime is of relatively minor importance. In summary, our study clearly suggests that there are temporal differences in the relative importance of different assembly mechanisms related to abiotic factors and shows that the temporal variability of those factors is important for a more complete understanding of bacterial metacommunity dynamics.
跨空间的群落组成周转率，β-多样性，受到不同组装机制的影响，这些机制对当地生境因素（如环境条件和物种相互作用）和区域因素（如扩散和历史）赋予不同的权重。 几种组装机制可能同时起作用；然而，对于它们的重要性随时间如何变化以及为什么会发生变化，我们知之甚少。 在这里，我们进行了一项实地调查，在一年中的 11 个时间点对位于瑞典波罗的海沿岸的 17 个岩石池中存在的细菌宏群落进行了采样。 我们使用变异划分来确定群落受不同组装机制影响的程度，并研究了随时间推移环境梯度上 β-多样性的变化。 在宏群落中，整体生产力和环境异质性较高的时期，群落的β-多样性最高，这至少部分归因于物种分选，即由主导环境条件选择的分类群。 相比之下，在β-多样性相对较低的时期，主要检测到由扩散驱动的组装机制。 永久性和临时性水池之间的群落组成或β-多样性没有明显的差异，表明物理干扰对群落的影响相对较小。 综上所述，我们的研究清楚地表明，与非生物因素有关的不同组装机制的相对重要性存在时间差异，并表明这些因素的时间变异性对于更全面地理解细菌宏群落动态非常重要。
