The role of hydroperiod and fluctuating temperature on disease dynamics: A disease ecology approach to understanding Yosemite toad declines

Abstract

Environmental factors can alter host-pathogen interactions. Temperature and water availability are critical environmental factors that affect disease susceptibility in amphibian hosts due to amphibian thermal biology. Temperature and water can also alter prevalence and virulence of the amphibian pathogen Batrachochytrium dendrobatidis (Bd), because Bd requires moisture and temperatures between 2-27°C to replicate. Understanding disease dynamics under fluctuating temperatures and changes in water availability is important because climate change is likely to affect these environmental factors across local and landscape scales with potential implications for disease. Investigating the effects of environment on disease outcomes for imperiled species may inform conservation and recovery efforts. To better understand the effects of reduced water availability and fluctuating temperature on disease, I examined (1) the effects of larval development under drought conditions on disease susceptibility post-metamorphosis in Yosemite toads; and (2) the effects of daily fluctuating temperatures on Bd growth and reproduction rate in vitro.