Infection dynamics of Batrachochytrium dendrobatidis in subtropical amphibian communities

Batrachochytrium dendrobatidis (Bd) is a pathogenic fungus causing population declines and extinctions of amphibians globally. Anthropogenic habitat alteration can directly and indirectly influence host-pathogen interactions by modifying wetland microclimates, physicochemical profiles, and amphibian communities. To test the combined effects of host-specific traits and environmental factors on Bd infection dynamics, we sampled 581 amphibians from 12 species in Tuscaloosa County, Alabama, USA. We tested the influence of host traits (body size and ecological behavioral habit) and environmental factors (habitat disturbance and water temperature) on Bd prevalence and infection loads, while body size was included in the models only as a covariate to control for potential effects on infection parameters. Bd was detected in 127 individuals (22% community prevalence) across 6 frog and 2 salamander species. Aquatic amphibians showed higher Bd prevalence and loads than terrestrial and arboreal species, with no significant differences between the latter 2 groups. Higher water temperatures were associated with lower Bd prevalence and loads, while body size and habitat disturbance were not important Bd predictors. These results emphasize the influence of host traits and environmental factors on Bd dynamics, expanding our understanding of amphibian host-pathogen interactions in an understudied region.