In general, my research is multidisciplinary and characterized by rigorous quantitative approaches to questions relevant to ecology, biogeography, and conservation biology, all considered from an evolutionary perspective. My investigative approach is based on both manipulative and observational experiments, as well as on modeling exercises. My research is strongly organismal in nature and is not limited by taxonomic constraints, as evidenced by publications concerning bacteria, fungi, plants, snails, insects, reptiles, birds, and mammals. Nonetheless, the major thrust of my research has concerned terrestrial mammals, especially those in tropical regions. I have broad experience conducting field research in a diversity of habitats, including both aquatic and terrestrial environments. Aquatic research has focused on phytotelmata, streams, and ephemeral lakes (e.g., playas). Terrestrial work has been conducted in semiarid tropical thorn-scrub, tropical grassland-savanna, tropical rainforest, subtropical forest, and temperate forest. As a consequence, I currently have or recently have had funded research programs in Paraguay(NSF), Brazil(USDA), Puerto Rico(NSF), Peru(NIH), and the U.S. (NSF).