My research has two major themes:
Predictive models of fish distributions
What factors control the composition of fish communities in lakes? Does the absence of a species reflect dispersal barriers, biotic interactions or local environmental factors? How will future climate changes affect species distributions? I use extensive data on present and historical distributions, the outcome of species introductions and colonization after rotenone treatment to answer these questions.
Spatial scaling laws in ecology
Can the results of small-scale experiments be extrapolated to much-larger natural systems? Answering this critical question requires that we know when ecological responses are scale dependent. Important scale dependent phenomena that I study are migration rates and the combination of spatial heterogeneity and nonlinearity. My approach is often to derive simple mathematical models of scale-dependent processes and to test them with meta-analyses of published data.