Amphibians on the Decline

According to BBC News, the United Nations biodiversity agency IUCN believes it would cost over $400 million to save the world's amphibians (frogs, toads, and salamanders) from extinction. About one-third of the world's amphibians are at a high risk of extinction. The IUCN cited six causes of the global declines including infectious disease (mainly chytridiomycosis), climate change, chemical contamination, invasive species, over-harvest, and habitat loss and degradation.

The situation in Rocky Mountain National Park reflects, to some extent, the global situation. Of the five species of amphibians documented from the park, one, the leopard frog (Rana pipiens) , is extirpated (apparently locally extinct) and the boreal toad (Bufo boreas) has declined dramatically in the last decade. What is the cause? We have no firm answers. Researchers from the U.S. Geological Survey working in the park have documented chytridiomycosis in many of the park's amphibians, including boreal toads. From the above list of threats, some indicators of climate change and chemical contamination have been documented from the park, but not directly linked to effects on amphibians. The last three threats on the list are far less likely to be directly affecting park amphibians.

Based on amphibian declines linked to the apparently recent appearance of chytridiomycosis globally, researchers have been trying to determine the disease's origin. One recent, intriguing hypothesis suggests it may have been spread as a result of use of African frogs in human pregnancy tests in the 1930s and 1940s. Dr. Rick Speare of James Cooke University in Townsville, Australia has found the oldest known evidence of chytridiomycosis in South African clawed frog (the species used in the pregnancy tests) in museum specimens and proposed the theory which is currently being discussed in scientific circles. Whatever the source, this deadly disease appears to be a major contributor to mortality of amphibians in Rocky Mountain National Park and globally.

Rocky Mountain National Park is currently working closely with the USGS Amphibian Research and Monitoring Initiative to keep tabs on amphibians in the park in relation to other amphibian populations along the Continental Divide including Glacier, Yellowstone, and Grand Teton National Parks. Research includes investigations into the demographic characteristics of populations such as survival; genetic structure of the wood frog population in the Kawuneeche Valley; and close monitoring of boreal toad populations throughout the park.