My research interests lie at the nexus of three different levels of ecological organization– the population, community and the ecosystem. At a broad level, I am interested in the ecological forces that maintain terrestrial ecosystem stability and function. My approach is to analyze how focal interactions among two or three species are affected by feedbacks in the community and ecosystem. I have applied this approach to a variety of systems, including host-parasitoid interactions, mutualisms, plant-pathogen and arctic mammalian communities. My work is largely theoretical, involving the analysis, both mathematical and computational, of dynamical systems representing simplified interaction webs. I use the results of this analysis to create hypotheses to explain existing empirical patterns, or to predict patterns that have not been previously measured.