Global change impacts on isolated wetlands and pond breeding amphibians

Isolated wetlands are a critical landscape feature throughout North America, where they provide surface water storage and localized groundwater recharge, reduce groundwater pollution, and provide critical habitat for pond breeding amphibians and numerous other taxa. Isolated wetlands are disappearing rapidly due to land-use changes. Those that remain are changing due to altered weather patterns which affect how long a wetland holds water. These changes have impacts across levels of biological organization. We examine these impacts at multiple levels from genome to ecosystem. Some of our recent work focuses on how amphibian communities are shifting over time and how these changes interact with environmental factors to influence the prevalence of ranavirus, an emerging infectious disease of ectothermic vertebrates.

Aquatic pollution & Evolutionary Toxicology

Exposure to pollution can impact individuals in ways that affect population persistence, community assembly, and ecosystem services. A large focus of our research involves metal contaminants, especially copper and mercury, that are widespread in aquatic habitats and pose a significant threat to aquatic life. We use a combination of controlled laboratory studies, mesocosm studies, in situ rearing along with genetic techniques. We find substantial variation in tolerance to metals within and across species and that some populations can rapidly adapt to mixtures of metals from coal combustion wastes. Currently, we are investigating how spatial and temporal variation in aquatic contamination affects: patterns of gene flow, selection, and genome-wide changes in genetic diversity.



Conservation and management of freshwater vertebrates

In addition to testing broader ecological and evolutionary questions, a focus of our research includes on-the-ground applied conservation of at-risk species. Species we are currently focusing on include Carolina gopher frogs and American alligators. Gopher frog populations are declining rapidly and we have been working with state agencies in Florida, Georgia, North Carolina and South Carolina to survey populations and examine pattern of genetic variation. We are really excited to start our new project working with the Longleaf Alliance and private landowners in SC to find wetlands supporting gopher frog breeding and make recommendations for managing wetlands and the surrounding uplands to improve and/or maintain gopher frog habitat. We also work closely with The Tom Yawkey Wildlife Center and SC Department of Natural Resources on alligator population genetics and are examining patterns of gene flow across their range to work with state agencies in managing alligator hunts.