Study: Global warming may be taking toll on West pikas

RENO - Populations of the American pika - a hamster-like rodent unable to survive in warm climates - continue to decline in the West, apparently due in part to global warming, a new study says.

Local populations of pikas have gone extinct at more than one-third of 25 sites surveyed since the mid-1990s in the Great Basin region between the Sierra Nevada and Rocky Mountains, according to the study conducted by a researcher for the U.S. Geological Survey and funded by the World Wildlife Fund.

"Population by population, we're witnessing some of the first contemporary examples of global warming apparently contributing to the local extinction of an American mammal at sites across an entire eco-region," said Erik Beever, a USGS ecologist.

Pikas, a relative of the rabbit with small, round ears, are known for their high-pitched whistle often heard when humans approach. They gather vegetatiln for food and make their homes among broken rocks at high elevations of mountain ranges in the western United States and southwest Canada.

Beever published a study in the Journal of Mammalogy in February 2003 that found populations of pikas had disappeared at seven of the 25 sites where he had documented them in the mid- to late-1990s in California, Oregon and Nevada.

Results of a follow-up field study this summer showed extinctions at two more of seven resurveyed sites for a total of nine sites where they no longer exist, or 36 percent, Beever said. He said he intends to publish details of those findings after he completes another round of surveys n

"At the places where they have been lost, the sites were hotter and drier than sites where they have remained," Beever said in a telephone interview.

Previous research suggests American pikas are vulnerable to global warming because they live in areas with cool, relatively moist climates, Beever said. They've been shown to be unable to survive just six hours in temperatures as cool as 77 degrees, he said.

Beever, who did his graduate work at the University of Nevada, Reno, now works out of the USGS Forest and Rangeland Ecosystem Science Center in Corvallis, Ore. His previous research suggested climate change may be interacting with other factors, such as increased road building and smaller habitat areas, to increase extinction risks.

Brooks Yeager, vice president in charge of global threats at the World Wildlife Fund in Washington D.C., said the new data shows the importance of efforts to combatting global warming by reducing heat-trapping emissions from the burning of fossil fuels.

"Extinction of a species, even on a local scale, is a red flag that cannot be ignored," Yeager said.