I am an ecologist interested in the dynamics and fate of animal populations and communities. My research program is organized around two primary themes:
Emerging Diseases. Limb deformities of amphibians are a well described emerging disease phenomenon of uncertain cause. The leading hypothesis has been an infectious agent Ribeiroia, a trematode parasite. Our work in Vermont, an epicenter for amphibian deformities, shows that high rates of limb deformities can occur in the absence of Ribeiroia requiring an alternate mechanism such as chemical pollutants. We are building on this research in collaboration with Gunter Wagner (EEB). A pilot grant from the Yale Medical School is enabling us to gather initial data exploring the genetic basis for abnormal limb development in the presence of chemical pollutants. Our initial results suggest that genome wide expression patterns (using gene-chip technology) will provide an excellent basis for understanding the causes of abnormal development. A complementary project explores the role of urbanization in promoting infectious disease in wildlife. A survey of Connecticut wetlands shows that amphibians living in urban areas can suffer intense kidney infections. These outbreaks by echinostome trematodes are previously unrecognized and potentially debilitating to urban wildlife.
Population Responses to Dynamic Landscapes. Human activities lead to rapid changes in landscapes across much of the Earth’s surface. In the freshwater wetlands I study, one of the most profound effects is the change in forest structure in and around wetland basins. Either by directly removing trees, controlling beaver populations, or suppressing fires the canopy cover over ponds can be dramatically affected and rapidly changed. We have shown that amphibian populations are sensitive to such changes. Population extinctions are one common response. More recently we have discovered that one of our study species, the wood frog, is capable of rapid evolutionary response to changing temperature altered by canopy removal or regrowth. This surprising finding in a vertebrate implies that responses to other thermal changes, such as those associated with climate change are possible and even likely. The recognition of evolved response could greatly influence estimates of the ecological consequences of climate change.