Our research interests focus on the evolution of ecology in mammals. Specific research questions generally relate to the roles of biotic and physical environmental forcing in driving evolution within mammals. In studying this process, we take both lineage-based and ecosystem-based approaches. Our major unifying project examines the evolution of North American fossil mammals from an ecosystem perspective: the spread of cool, dry climates through the Oligo-Miocene in North America provides an opportunity to examine the way modern mammal communities were assembled and the role environmental forcing plays in this assembly. Field and museum studies of the fossil mammal assemblages of the Oligocene and Miocene of Oregon and surrounding areas seek to understand spatio-temporal differences in the structure of mammalian communities.

We examine evolution within lineages of mammals, both fossil and living, using phylogenetic and comparative methods. Ongoing work on patterns of ecological evolution generate databases of modern ecological observations and apply them to phylogenetic comparative studies using extant-only phylogenies. These studies are then used to generate hypotheses that can be tested in the fossil record. We take our work into deep time, generating phylogenies for clades of extinct mammals and use the resulting evolutionary patterns to test hypotheses about interactions between changes in the physical and biotic environment and ecological evolution.  Ongoing studies include Antilocapridae (American antelope) Aplodontidae (sewellels) and Sciuridae (squirrels). All these clades diversified during the Oligocene and Miocene of North America, a time and place that forms our primary study system.

Both aspects of our research provide a basis for understanding how the record of extinct mammals can inform modern conservation planning in the face of human-mediated ecological change.