Data from: Warming magnifies predation and reduces prey coexistence in a model litter arthropod system

Climate warming can destabilize interactions between competitors as smaller organisms gain advantages in warmer environments. Whether and how warming-induced effects on competitive interactions are modified by predation remains unknown. We hypothesized that predation will offset the competitive advantage of smaller prey species in warmer environments because of their greater vulnerability to predation. To test this, we assembled a litter arthropod community with two Collembola species (Folsomia candida and Proisotoma minuta) of different body sizes across a temperature gradient (three thermal environments) and in the presence and absence of predatory mites. Predatory mites reduced Collembola coexistence with increasing temperatures. Contradicting our hypothesis, the larger prey species always outperformed the smaller prey species in warmer environments with predators. Larger prey probably benefited as they expressed a greater trait (body length) plasticity to warming. Warming can thus magnify predation effects and reduce the probability of prey coexistence.

气候变暖可破坏竞争物种间的相互作用，使体型更小的生物在升温环境中更易获得竞争优势。目前尚不清楚捕食作用是否以及如何调控气候变暖对物种竞争相互作用的影响。我们提出如下假说：由于小型猎物对捕食作用的敏感性更高，捕食作用可抵消升温环境下小型猎物的竞争优势。为验证该假说，我们构建了包含两种不同体型弹尾目（Collembola）物种的凋落物节肢动物群落，分别为白色棘跳虫（Folsomia candida）与小原等跳虫（Proisotoma minuta），设置了覆盖三个热环境的温度梯度，并设置有捕食螨（predatory mites）与无捕食螨两组处理。结果显示，随着温度升高，捕食螨会降低弹尾目物种的共存概率。与我们的假说相悖，在存在捕食螨的升温环境中，体型更大的猎物物种始终表现出比小型猎物更强的竞争优势。体型更大的猎物或因对升温表现出更强的性状（体长）可塑性而获益。因此，气候变暖可放大捕食作用的调控效应，并降低猎物物种的共存概率。