Spatial insurance in multi-trophic metacommunities

Metacommunity theory suggests that dispersal is a key driver of diversity and ecosystem functioning in changing environments. The capacity of dispersal to mitigate effects of environmental change might vary among trophic groups, potentially resulting in changes in trophic interactions and food web structure. In a mesocosm experiment, we compared the compositional response of bacteria, phyto- and zooplankton to a factorial manipulation of acidification and dispersal. We found that the buffering capacity of dispersal varied among trophic groups: dispersal alleviated the negative effect of acidification on phytoplankton diversity mid-experiment, but had no effect on the diversity of zooplankton and bacteria. Likewise, trophic groups differed in whether dispersal facilitated compositional change. Dispersal accelerated changes in phytoplankton composition under acidification, possibly mediated by changes in trophic interactions, but had no effect on the composition of zooplankton and bacteri...集合群落理论（Metacommunity theory）指出，在变化环境中，扩散（dispersal）是调控生物多样性与生态系统功能的关键驱动因子。扩散缓解环境变化负面影响的能力可能因营养类群（trophic groups）而异，进而可能改变营养相互作用与食物网结构。本研究通过中宇宙实验（mesocosm experiment），对比了细菌、浮游植物（phytoplankton）与浮游动物（zooplankton）对酸化（acidification）与扩散的析因操控的群落组成响应。研究结果显示，扩散的缓冲能力（buffering capacity）存在营养类群差异：实验中期，扩散缓解了酸化对浮游植物多样性的负面影响，但对浮游动物与细菌的多样性无显著影响。同样，不同营养类群在扩散是否促进群落组成变化方面存在差异。在酸化条件下，扩散加速了浮游植物的群落组成变化，这一过程可能由营养相互作用的改变所介导，但对浮游动物和细菌的组成无显著影响……