| Summary: | The multifaceted role of the environment in regulating the structure and dynamics of biological communities has long fascinated ecologists and motivated much debate and research. Now, in a time of accelerated global changes due to human impacts, the need to understand how the environment shapes communities has gained new urgency. The environment acts directly on communities by causing direct mortality and changes to vital rates of individuals. However, the environment can also exert indirect effects on communities by changing the nature of biotic interactions. This occurs either through changes to the physiological performance of interacting species or through shifts in the abundance of other species in the community. Much of the effort to understand how global change will influence communities has focused on direct effects of environmental conditions. However, the essential influence of biotic interactions suggests that we will need to improve our conceptual understanding of indirect environmental effects to better predict outcomes of anthropogenic change.Understanding how the interactions of predators and prey are vulnerable to environmental context may provide a useful pathway to link relatively well-resolved individual effects of climate change to a broader community context. Predators are often important in determining community structure and stability through their control of lower trophic levels. However, predators also tend to be particularly sensitive to environmental stress. As a result, environmental stress models predict that the impacts of predators will lessen as stress increases, which could weaken existing processes regulating communities. Top predators, which often have the strongest impacts, may be especially vulnerable to climate change because of their large body size, energy needs, range requirements, and dependence on prey populations. The effects of environmental change on top predators have been justifiably well-studied, yet changing contexts require a more comprehensive view of which ...
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