- Cool, dry conditions limit Yellowstone's amphibians to four species.
- Population numbers for these species are not known.
- Amphibians: boreal toad, chorus frog, spotted frog, tiger salamander.
The spotted frog may be declining in the West.
Some researchers suspect that there are more amphibians in Yellowstone than are currently known, but this has not been documented yet.
Yellowstone is home for a small variety of amphibians. Glacial activity and current cool and dry conditions are likely responsible for their relatively low numbers in Yellowstone.
In 1991 park staff began cooperating with researchers from Idaho State University to sample additional park habitats for reptiles and amphibians. This led to establishment of long-term monitoring sites in the park (map, page 119). The relatively undisturbed nature of the park and the baseline data may prove useful in testing hypotheses concerning the apparent declines of several species of toads and frogs in the western United States. Reptile and amphibian population declines may be caused by such factors as drought, pollution, disease, predation, habitat loss and fragmentation, introduced fish and other non-native species.
Although no Yellowstone reptile or amphibian species are currently listed as threatened or endangered, several-including the boreal toad-are thought to be declining in the West. Surveys and monitoring are underway to try to determine if amphibian populations are declining in Yellowstone National Park.