Yellowstone amphibians in decline due to climate change
October 27, 2008
Using surveys and remote sensing to monitor and record changes in wetlands in northern Yellowstone National Park, Sarah McMenamin of Stanford University and colleagues linked declining amphibian populations to drier and warmer conditions over the past 60 years, including a four-fold increase in the number of number of permanently dry ponds over the past 16 years.
"Of the ponds that remain, the proportion supporting amphibians has declined significantly, as has the number of species found in each location," the authors write. "Our results indicate that climatic warming already has disrupted one of the best-protected ecosystems on our planet and that current assessments of species' vulnerability do not adequately consider such impacts."
A view of the glacially modified topography of Lamar Valley in Northern Yellowstone. Slough Creek is visible, as are the many permanent and ephemeral glacial kettle ponds. These ponds are breeding and living habitat for four different species of amphibian. Widespread drought is causing the desiccation and destruction of many of these habitats, which has caused significant and severe declines in regional amphibians. Photo by Sarah McMenamin in 2007
"Our data suggest that climatic change is causing substantial changes to the hydrologic landscape and that amphibian populations are being damaged by both habitat loss and other climate-associated mechanisms," they write. "Precipitous declines of purportedly unthreatened amphibians in the world’s oldest nature reserve indicate that the ecological effects of global warming are even more profound and are happening more rapidly than previously anticipated."
The species native to Northern Yellowstone include the blotched tiger salamander (Ambystoma tigrinum melanostictum), the boreal chorus frog (Pseudacris triseriata maculata), the Colombia spotted frog (Rana luteiventris, formerly Rana pretiosa), and the less common boreal toad (Bufo boreas boreas). No exotic amphibians are present in the region.
Sarah K. McMenamin, Elizabeth A. Hadly, and Christopher K. Wright (2008). Climatic change and wetland desiccation cause amphibian decline in world's oldest national park. PNAS Early Edition for the week of October 27, 2008.
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