Ecology. Biotic multipliers of climate change.

M any species face uncertain fates under climate change. Some will persist by shifting their range or adapting to local conditions, whereas others will be lost to extinction. Efforts to lessen the impacts of climate change on biodiversity depend on accurate forecasts. Most studies aiming to identify likely winners and losers consider species one at a time with a “climate envelope” approach that correlates species’ occurrences with climatic and environmental variables. Using this method, researchers have predicted that by 2050, 15 to 37% of species will be faced with extinction ( 1). But which species are most likely to be under threat? And how will their loss affect the broader ecological community? The climate envelope approach ignores a core truth of ecology: Species interact with each other in ways that deeply affect their viability. Certain species impart particularly strong effects on others. Consequently, climate change impacts on these species could initiate cascading effects on other species. In effect, these species act as biotic multipliers of climate change. The inherent complexity of species interaction networks has discouraged their consideration in predictions. Emerging research illustrates that trophic interactors are especially strong candidates for biotic multipliers of climatic change. Focusing on these species and their interactions is one path through the complexity. Recent fi ndings highlight the importance of undisturbed vertical interactions involvBiotic Multipliers of Climate Change ECOLOGY