Fear mediates trophic cascades: nonconsumptive effects of predators drive aquatic ecosystem function

Predators control prey populations and influence communities and the functioning of ecosystems through a combination of consumptive and nonconsumptive effects. These effects can be locally confined to one ecosystem but can also be extended to neighboring ecosystems. In this study, we investigated the nonconsumptive effects of terrestrial avian predators on the communities of aquatic invertebrates inhabiting bromeliads and on the functioning of these natural ecosystems. Bromeliads with stuffed birds placed nearby showed a decrease in aquatic damselfly larvae abundance and biomass, and we can infer that these changes were caused by antipredator responses. These larvae, which are top predators in bromeliad ecosystems, changed the composition of the entire aquatic invertebrate community. While total species richness, mesopredator richness, and shredder abundance increased in the presence of birds, scraper biomass decreased, possibly as a consequence of the increase in mesopredator richness....

捕食者通过消耗性效应（consumptive effects）与非消耗性效应（nonconsumptive effects）的共同作用，调控猎物种群，并对群落结构与生态系统功能产生影响。这些效应既可局限于单一生态系统内部，也可延伸至邻近的生态系统。本研究探究了陆生鸟类捕食者的非消耗性效应，及其对附生凤梨（bromeliads）栖息的水生无脊椎动物群落与该类自然生态系统功能的影响。放置了剥制鸟类标本的附生凤梨，其栖息的水生豆娘幼虫丰度与生物量均出现下降；据此可推断，该变化源于猎物的反捕食响应（antipredator responses）。这些作为附生凤梨生态系统顶级捕食者的幼虫，会改变整个水生无脊椎动物群落的组成结构。当鸟类存在时，总物种丰富度、中级捕食者（mesopredator）丰富度与碎食者（shredder）丰度均有所提升，但刮食者（scraper）生物量却出现下降，这可能与中级捕食者丰富度的增加有关……