DISSERTATION RESEARCH: Effects of Host Community Structure on Amphibian Disease Risk

Amphibians are the most threatened group of vertebrate animals, due primarily to deforestation and a fungal disease that has spread globally and is causing devastating declines in population sizes that has driven some species to extinction. To implement effective conservation strategies in the wild, we need to understand how habitat change and disease threats interact. According to recent findings, simply protecting natural habitats is not the answer for amphibian conservation, because the emerging fungal pathogen infects amphibians in pristine forests more than those living in agricultural and urban areas. This double threat leaves amphibians little refuge, as most species that suffer from disease cannot escape infections in disturbed habitats. One hypothesis for this paradoxical pattern is that higher amphibian numbers and diversity in natural habitats hold a greater potential for pathogen transmission and spread. This project will test this hypothesis by examining frog assemblages in both pristine and modified habitats in Brazil and experimentally infecting individuals from each assemblage with the fungal pathogen under controlled laboratory conditions. Frogs from both pristine and disturbed habitats will be monitored for changes in infection patterns, and those disease dynamics will be correlated with number and identity of species, density of individuals, and body size. Understanding how changes in frog assemblages caused by land use change can affect disease dynamics will provide a more complete picture of the interaction between deforestation and emerging diseases, the two main factors at the root of the amphibian decline crisis.

The project will strengthen research collaborations with Brazilian scientists studying amphibian species loss. Results from this work will be useful in developing strategies to conserve the diversity of amphibian species in the tropics. Brazil has the highest number of amphibian species anywhere in the world, thus, this project will contribute to the management of a mega-diverse fauna. This project will provide research opportunities for undergraduate students to conduct field research and will contribute to the doctoral research of a graduate student.