The Arctic ground squirrel population is in decline because their mating season is affected by the warming Alaskan climate.

North of Alaska's boreal forest lies the tundra of the North Slope. Thirty years ago, scientists set up an isolated field station at Toolik Lake to conduct long-term research on the area's ecosystem. Instead, many have found themselves studying the changing climate.

Arctic ground squirrels are one species scientists have been following at Toolik. The squirrels depend on a brief spring breeding period after their eight months of hibernation underground. But climate warming is producing unfavorable spring conditions, so the squirrels are in decline.

Squirrels are a key prey species on the North Slope, food for grizzly bears, eagles, foxes and wolves. Like the guillemots studied by George Divoky on Cooper Island, it's not clear whether, or how, any of these tundra inhabitants will adapt to changing conditions.

For more on this topic, see the web feature:
Arctic Species at Risk