Section of Evolution and Ecology and Center for Population Biology, One Shields Avenue, University of California Davis, Davis, CA 95616-8755, USA.
Science. 2011 Jan 28;331(6016):461-3. doi: 10.1126/science.1200282.
The effect of environmental change on ecosystems is mediated by species interactions. Environmental change may remove or add species and shift life-history events, altering which species interact at a given time. However, environmental change may also reconfigure multispecies interactions when both species composition and phenology remain intact. In a Caribbean island system, a major manifestation of environmental change is seaweed deposition, which has been linked to eutrophication, overfishing, and hurricanes. Here, we show in a whole-island field experiment that without seaweed two predators--lizards and ants--had a substantially greater-than-additive effect on herbivory. When seaweed was added to mimic deposition by hurricanes, no interactive predator effect occurred. Thus environmental change can substantially restructure food-web interactions, complicating efforts to predict anthropogenic changes in ecosystem processes.
环境变化对生态系统的影响是通过物种相互作用来调节的。环境变化可能会去除或添加物种，并改变生活史事件，从而改变特定时间相互作用的物种。然而，当物种组成和物候期保持不变时，环境变化也可能重新配置多物种相互作用。在加勒比岛屿系统中，环境变化的一个主要表现是海藻沉积，这与富营养化、过度捕捞和飓风有关。在这里，我们在全岛野外实验中表明，没有海藻时，两种捕食者——蜥蜴和蚂蚁——对食草作用的影响远远超过了加性效应。当添加海藻来模拟飓风沉积时，不会发生相互作用的捕食者效应。因此，环境变化可以极大地改变食物网相互作用，从而使预测人为改变生态系统过程的努力变得复杂。
