Amphibians disappear from Yellowstone

STANFORD, Calif., Oct. 29 (UPI) -- A U.S. study suggests global warming is causing a "catastrophic" decrease in the numbers of frogs and salamanders living in Yellowstone National Park.

Stanford University graduate student Sarah McMenamin has spent three summers in a remote area of the park searching for frogs and salamanders in ponds that had been surveyed 15 years ago. She and Associate Professor Elizabeth Hadly say they've determined the decrease in the numbers of the amphibious environmental bellwethers is being caused by global warming.

Hadly, a co-author of the research paper, said the amphibians need the park's ponds for their young to hatch, but higher temperatures and drought are causing the water to evaporate.

"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 researchers wrote.

"They're just blinking off. It's depressing," added Hadly.

The researchers said they studied 100 years of climate and water records but could find no cause for the drying ponds other than a persistent change in temperature and precipitation.

The research appears in the online edition of the Proceedings of the National Academy of Sciences.