Presented By: Ecology and Evolutionary Biology
EEB Seminar Series - Special Day!
Effects of predator diversity and climate change on agricultural pests, presented by Dr. Tobin Northfield, University of Wisconsin
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 Dr Tobin used an experimental response-surface design, varying intra- and interspecific predator densities. By statistically fitting mechanistic models to the data, he 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 him to quantify overlap in resource use by the different predator species. Dr Tobin then theoretically explored the effects of climate change on interacting species. Predicting the consequences of interspecific interactions is complicated by coevolution between species. Therefore, he used simple models to organize and synthesize the ways coevolution modifies species coexistence when climatic changes favour one species over another. In cases where species have conflicting interests, he shows 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. Dr Tobin discusses 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.