Global warming ruffles wildlife, study says

February 15, 2000

Web posted at: 2:33 PM EST (1933 GMT)

By Environmental News Network staff

Climate change may be disrupting the hibernation and migration patterns of animals and birds, according to a recent study.

A study in the Feb. 15 issue of the Proceedings of the National Academy of Sciences indicates that global warming may pose special challenges to species that depend on seasonal cues for their survival.

Despite a trend toward warmer spring temperatures, the average snowmelt in areas of high altitude has not changed, noted David Inouye, lead author of the study. And the snow pack might be getting deeper with time.

"One prediction of climate change is that winter snow packs are actually increasing," he said.

"Vegetation (which depends on snow melt) is not happening earlier at high altitudes, but species are arriving earlier," Inouye added.

For example, marmots, which usually hibernate for eight months, are emerging earlier, risking starvation as they wait longer and longer for the snow to melt. Marmots are appearing 38 days earlier than they did 23 years ago, according to the study.

Similarly, American robins are migrating an average of two weeks earlier than they did 23 years ago, moving from low-altitude wintering grounds to high-altitude summer breeding grounds. They, too, must wait longer for the snow to melt before they can feed and nest.

"Marmots are in more of a bind because they don't have the energy to walk to lower altitudes," Inouye said. "We're concerned that many are starving to death."

"In the past, a marmot's ability to detect warmer temperatures was advantageous because it signaled an early spring, which resulted in a longer growing season [that enhanced the marmot's] survival and reproduction," said Kenneth Armitage, co-author of the study. "Now it appears the marmot's response to temperature may have a negative effect."

Inouye suggests that some animals may be able to adapt to climate change resulting from global warming. "It is possible that over evolutionary time the situation could correct itself. Nevertheless, we worry that climate change may be happening more quickly [than evolution]"

In an upcoming study, the researchers plan to investigate how climate change affects the migration patterns of hummingbirds traveling from Mexico to Colorado.