Changes in stream food web structure across a gradient of acid mine drainage increases local community stability

Understanding what makes food webs stable has long been a goal of ecologists. Topological structure and the distribution and magnitude of interaction strengths in food webs have been shown to confer important stabilizing properties. However, our understanding of how variable species interactions affect food web structure and stability is still in its infancy. Anthropogenic stress, such as acid mine drainage, is likely to place severe limitations on the food web structures possible due to changes in community composition and body mass distributions. Here, we used mechanistic models to infer food web structure and quantify stability in streams across a gradient of acid mine drainage. Multiple food webs were iterated for each community based on species pairwise interaction probabilities, in order to incorporate the variability of realistic food web structure. We found that food web structure was altered systematically with a 32-fold decrease in the number of links and a 2-fold increase in ...

探明食物网（food web）稳定性的驱动机制，长期以来都是生态学家的核心研究目标。食物网的拓扑结构、种间相互作用强度的分布与量级，已被证实可赋予其重要的稳定特性。然而，学界对于可变的物种间相互作用如何影响食物网结构与稳定性的认知，仍处于起步阶段。人为胁迫，如酸性矿山排水（acid mine drainage），可能会通过改变群落组成与体型分布，对可行的食物网结构造成严重限制。本研究采用机理模型（mechanistic models），对沿酸性矿山排水梯度的溪流食物网结构进行推断，并量化其稳定性。为纳入真实食物网结构的变异性，本研究基于物种两两相互作用概率，对每个群落迭代生成多个食物网实例。研究发现，食物网结构发生了系统性改变：连接数减少32倍，而……增加2倍。