Chytrid Fungus in the Rocky Mountains

Research Task: 3214A80.11.0
Task Manager: Erin Muths

The boreal toad was once widely distributed and locally abundant across the Rocky Mountains, but has disappeared from many historic localities from Montana to Colorado over the last 20-30 years. Boreal toads appear to have suffered increasingly widespread declines along a gradient in the Rocky Mountains from north to south, a pattern possibly associated with the distribution of chytrid fungus. In the western U.S., chytrid fungus has the features of an introduced, lethal infectious disease to which amphibian populations have no resistance, and it has been associated with population declines in several species. Information on the distribution of chytrid, the susceptibility of populations to chytridiomycosis, and the role of chytrid in amphibian population declines is critical for determining which amphibian populations are at risk and for making conservation decisions about which habitats and or populations are the most important to protect and monitor. This research documented the distribution of chytrid fungus in boreal toad populations along an 11 degree latitudinal gradient in the Rocky Mountain region of Wyoming and Montana, and established 3 apex sites at robust boreal toad populations in Colorado, Wyoming, and Montana. Scientists monitored the status of and threats to populations at these 3 sites and used the data to recommend conservation measures to protect these unique populations on a regional scale. They also used capture-recapture population data for boreal toads and data on chytrid and contaminants to develop predictive models for examining possible interactions of disease and other stressors on amphibian population dynamics and persistence. We sampled 1247 amphibians at sites in 97 geographical clusters. The fungus was detected at 63 percent of clusters and occurred across a range of elevations (1030–3550 m) and latitudes (37.6–48.6 degrees).

 For more information contact Erin Muths