As the climate changes, high-elevation habitats in the Cascade Mountain Range are experiencing reduced snowpack and increasing temperatures. These climate-related changes will have particularly complex impacts for the amphibian species present in high-elevation habitats, which rely on their environment to regulate their body temperature. 

Amphibians are one of the most threatened animal groups, with 40% of species listed as threatened or endangered. A major driver of these declines is the disease Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which infects the skin of amphibian hosts and leads to death in at-risk species. Bd has been implicated in the decline of over 500 amphibian species and 90 presumed extinctions. Changing temperatures have been shown to influence Bd infection potential. This is especially true in amphibian populations with narrow temperature tolerances, including high-elevation Northwest species such as the Cascades Frog (R. cascadae), currently petitioned for listing under the Endangered Species Act. 

In the Northwest, although Bd has been shown to cause stress to amphibians, it has not led to mass mortality. In western North America, this apparent resistance is partly due to antimicrobial properties on the amphibian skin. However, the frequency of unusual and unseasonable weather conditions might disrupt Northwest amphibian species’ disease defense mechanisms (i.e., antimicrobial skin properties), which could lead to devastating outbreaks not yet experienced in the area. 

This project aims to understand the impacts of future climate shifts on the host-microbiome-disease relationship in Northwest amphibian populations. By comparing amphibian species’ specific microbial composition and infection rate across different elevations and temperatures, this project will provide insight into the future resilience of these amphibian disease defense mechanisms to climatic changes. This project will help increase understanding of how amphibian disease defense mechanisms and Bd prevalence will shift with a changing climate, which is necessary to be able to identify resilient and at-risk populations and prevent novel outbreaks of this devastating pathogen in the Northwest.