University of Michigan
Department of Ecology and Evolutionary Biology

Speaker: Tobin Northfield, USDA Postdoctoral Research Fellow, University of Wisconsin

Abstract
Recent studies suggest that climatic changes can disrupt predator communities, and may lead to increased pest outbreaks in agricultural fields. Understanding these effects necessitates a mechanistic understanding of both predator diversity on prey suppression and the eco-evolutionary response of communities to climatic changes. To compare patterns of predation between simple and diverse communities of aphid predators I used an experimental response-surface design, varying intra- and interspecific predator densities. By statistically fitting mechanistic models to the data, I demonstrated that resource partitioning rather than facilitation better explains the observed differences in resource use between simple and diverse predator communities.

This model-fitting approach also allowed me to quantify overlap in resource use by the different predator species. I then theoretically explored the effects of climate change on interacting species. Predicting the consequences of interspecific interactions is complicated by coevolution between species. Therefore, I used simple models to organize and synthesize the ways coevolution modifies species coexistence when climatic changes favor one species over another. In cases where species have conflicting interests, I show that coevolution reduces the effects of climate change, leading to reduced chances of extinction. Conversely, when species have non-conflicting interests, coevolution increases the effects of climate change, increasing extinction risk. Thus, coevolution sets up feedback loops that either dampen or amplify the effect of climate change on species extinctions, depending on the form that coevolution takes between species. I discuss these results in light of natural pest control in agroecosystems and potential future research evaluating the potential for sustainable food production in a changing climate.

Host: Professor Catherine Badgley

Coffee and cookies will be served at 4 p.m.