Studies of community assembly typically focus on the effects of abiotic environmental filters and stabilizing competition on functional trait dispersion within single trophic levels. Predation is a well‐known driver of community diversity and composition, yet the role of functionally diverse predator communities in filtering prey community traits has received less attention. We examined functionally diverse communities of predators (fishes) and prey (epifaunal crustaceans) in eelgrass (Zostera marina) beds in two northern California estuaries to evaluate the filtering effects of predator traits on community assembly and how filters acting on predators influence their ability to mediate prey community assembly. Fish traits related to bottom orientation were correlated with more clustered epifauna communities, and epifauna were generally overdispersed while fishes were clustered, suggesting prey may be pushed to disparate areas of trait space to avoid capture by benthic sit‐and‐wait predators. We also found correlations between the trait dispersions of predator and prey communities that strengthened after accounting for the effects of habitat filters on predator dispersion, suggesting that habitat filtering effects on predator species pools may hinder their ability to affect prey community assembly. Our results present compelling observational evidence that specific predator traits have measurable impacts on the community assembly of prey, inviting experimental tests of predator trait means on community assembly and explicit comparisons of how the relative effects of habitat filters and intraguild competition on predators impact their ability to affect prey community assembly. Integrating our understanding of traits at multiple trophic levels can help us better predict the impacts of community composition on food web dynamics as regional species pools shift with climate change and anthropogenic introductions.

中文翻译：

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跨营养级别扩展性状分散：捕食者组合充当猎物群落的自上而下的过滤器


群落组装的研究通常侧重于非生物环境过滤器的影响以及稳定竞争对单一营养水平内功能性状分散的影响。捕食是群落多样性和组成的众所周知的驱动因素，但功能多样化的捕食者群落在过滤猎物群落特征中的作用却很少受到关注。我们研究了鳗草中捕食者（鱼类）和猎物（表层甲壳类动物）功能多样化的群落（大叶藻）在加利福尼亚州北部的两个河口的河床中评估捕食者特征对群落组装的过滤效果，以及作用于捕食者的过滤器如何影响其调节猎物群落组装的能力。与底部方向相关的鱼类特征与更聚集的表层动物群落相关，而当鱼类聚集时，表层动物通常过度分散，这表明猎物可能被推到特征空间的不同区域，以避免被底栖静坐捕食者捕获。我们还发现捕食者和猎物群落特征分散之间的相关性在考虑了栖息地过滤对捕食者分散的影响后得到了加强，这表明栖息地过滤对捕食者物种池的影响可能会阻碍它们影响猎物群落组装的能力。我们的结果提供了令人信服的观察证据，表明特定的捕食者特征对猎物的群落组装具有可测量的影响，邀请对捕食者特征对群落组装的影响进行实验测试，并明确比较栖息地过滤器和行会内部竞争对捕食者的相对影响如何影响其能力影响猎物群落的组装。 整合我们对多个营养级特征的理解可以帮助我们更好地预测随着区域物种库随着气候变化和人为引入而发生变化，群落组成对食物网动态的影响。