Snowshoe hares moving farther north due to lack of snow

Snowshoe hare
CC BY 2.0 Denali National Park and Preserve/flickr

A changing climate and reduced snow cover across the north is pushing the forest dweller out of its historic range, says new study.

Snowshoe hares are all about the snow. With their chalky white coat and especially large furry feet that enable them to quickly scamper across deep snow, they are custom-built for cold wintry weather. They are the poster children for northern winter.

But according to new research from the University of Wisconsin-Madison, they are being pushed out of their range and taking to more northern climes due to a changing climate and reduced snow cover across the north. In Wisconsin, their range is moving up by about five and a half miles per decade, coinciding with the disappearing snow cover that the animals require for survival.

"The snowshoe hare is perfectly modeled for life on snow," says study co-author Jonathan Pauli, a UW-Madison professor of forest and wildlife ecology. "They're adapted to glide on top of the snow and to blend in with the historical colors of the landscape."

"Our winter climate has changed significantly over time," adds Ben Zuckerberg, another UW-Madison professor of forest and wildlife ecology and co-author of the study.

The new research analyzed 148 of 249 historic survey sites where the hares have been documented in the past. Of 126 sites where the animals were once reported, hares were found at only 28; the team was unable to find any hares at 78 percent of the places where they once lived.

Snowshoe hare© L. Scott Mills

"Color mismatch – white fur on a brown background -- will continue to occur and have a significant impact" on the species, says Pauli. "For a snowshoe hare, being cryptic is a fundamental requirement for making a living. It is a relatively fixed phenotype, so it is pretty clear that snow cover is one of the most important constraints in terms of where the animal can and can't be."

The Wisconsin study is important, say the researchers, because it helps show the impact of climate change on a sentinel species for northern ecosystems and illustrates how the “composition of plants and animals on the landscape is gradually shifting in a warming world.”

"The effects of climate change on biodiversity have emerged as a dominant theme in conservation biology, possibly eclipsing concern over habitat loss in recent years," notes the study, adding: "Projections of future range shifts show that climate change, and associated snow cover loss, will continue to be the major driver of this species' range loss into the future."

The study was published in Proceedings of the Royal Society B.

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