Identity effects dominate the impacts of multiple species extinctions on the functioning of complex food webs

Understanding the impacts of species extinctions on the functioning of food webs is a challenging task because of the complexity of ecological interactions. We report the impacts of experimental species extinctions on the functioning of two food webs of freshwater and marine systems. We used a linear model to partition the variance among the multiple components of the diversity effect (linear group richness, nonlinear group richness, and identity). The identity of each functional group was the best explaining variable of ecosystem functioning for both systems. We assessed the contribution of each functional group in multifunctional space and found that, although the effect of functional group varied across ecosystem functions, some functional groups shared common effects on functions. This study is the first experimental demonstration that functional identity dominates the effects of extinctions on ecosystem functioning, suggesting that generalizations are possible despite the inherent complexity of interactions.

由于生态相互作用的复杂性，理解物种灭绝对食物网功能的影响是一项具有挑战性的任务。我们报告了实验性物种灭绝对淡水和海洋系统两种食物网功能的影响。我们使用线性模型来划分多样性效应的多个组成部分（线性类群丰富度、非线性类群丰富度和特性）之间的方差。每个功能类群的特性是这两个系统中生态系统功能的最佳解释变量。我们评估了每个功能类群在多功能空间中的贡献，发现尽管功能类群的影响在不同生态系统功能之间存在差异，但一些功能类群对功能有共同的影响。这项研究首次通过实验证明功能特性在物种灭绝对生态系统功能的影响中起主导作用，这表明尽管相互作用具有内在的复杂性，但仍有可能进行归纳。