January 29 2015

11:00 158 Hershey Hall

Michelle Afkhami
Department of Ecology & Evolutionary Biology, University of Toronto

Biotic interactions as determinants of range limits


Understanding the processes determining species range limits is a central goal in ecology and evolution and critical for predicting species distributions under climate change. Recent work has produced new theory on the roles of biotic interactions in shaping species’ distributions, but these effects are rarely investigated over large geographic scales. Unlike competition and predation which contract a species’ range, positive interactions have the unique potential to ameliorate biotic and abiotic stressors, and thus may expand species niches, resulting in larger species ranges. Using a diverse set of approaches, including field surveys, common garden experiments throughout the range, species distribution modeling ,and greenhouse experiments, I will illustrate how positive species interactions between endophytic fungi and a California-native grass ameliorates both biotic and abiotic stresses and broadens the geographic range of the plant by thousands of square kilometers into drier habitats. These results suggest that positive biotic interactions may be under-appreciated in determining species’ ranges and species’ responses to future climates across large geographic scales.















































































































































































































































































































































































































































































































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