Disappearance of North American mammal linked to global warming
According to the new study, global warming appears to have contributed to local extinctions of American pika (Ochotona princeps) populations in the Great Basin — the area east of Sierra Nevada, west of the Rocky Mountains — during the latter part of the 20th century.
WWF is concerned that if the global warming trend is not reversed soon through a significant reduction in emissions of CO2 and other heat-trapping gases, further population losses of the American pika may occur.
“Losses of pikas are disturbing, because pikas are often locally abundant, and in decades past, scientists assumed that alpine and subalpine ecosystems were relatively undisturbed because of their isolation,” said Dr Erik Beever, an ecologist with the US Geological Survey’s Forest and Rangeland Ecosystem Science Centre and lead author of the study. “The responses of American pika populations are a signal of the impacts of climate change in alpine and subalpine systems."
A smaller relative of rabbits and hares, American pikas have short, round ears and make their homes among the broken rocks, or talus, at high elevations in the mountains of the western United States and southwestern Canada. Between 1994 and 1999, the study re-surveyed 25 sites where pikas were previously recorded; the earliest record occurred in 1898.
Although extent or distribution of talus habitat had changed negligibly during that time, pikas were detected at only 18 of the 25 original locations. Pikas had apparently vanished from the other seven locations in at most 55–86 years.
Research results show that American pikas are particularly vulnerable to global warming because they reside in areas with cool, relatively moist climates like those normally found in their mountaintop habitat. As temperatures rise due to increasing emissions of CO2 and other heat-trapping gases, many montane animals are expected to migrate northward or seek higher elevations in an attempt to find suitable habitat.
The American pika appears not as well-equipped as other species to handle this environmental shift. Results also suggest that climate may be interacting with other factors such as proximity to roads and smaller habitat area to increase extinction risk for pikas, creating detrimental synergistic effects.
American pikas may act as 'ecosystem engineers' at talus margins because of their extensive haying activities. Since food is difficult to obtain in winter in the alpine environment, pikas cut, sun-dry, and later store vegetation for winter use in characteristic ‘haypiles’ above a rock in talus areas.
“American pikas are unfortunately like the ‘canary in the coal mine’ when it comes to global warming,” said Jennifer Morgan, director of WWF’s Climate Change Programme.
“Their disappearance is a red flag that our heavy reliance on dirty fossil fuels is causing irreparable damage to our environment. We must make the switch to clean renewable energy resources like wind and solar now before it’s too late.”
For further information:
Communications Manager, WWF-US
Tel: +1 202 778 9576
Olivier van Bogaert
Press Officer, WWF International
Tel: +41 22 3649554