Climate Change Is Forcing This Rabbit to Search for Snow

As snowshoe hares flee northward to escape warming temperatures, their predators may go hungry.
(Photo: L. Scott Mills)
Apr 4, 2016· 1 MIN READ
Padma Nagappan is a multimedia journalist who writes about the environment, renewable energy, sustainability, agriculture, and biotechnology.

As winters have gotten shorter and warmer in northern forests, snowfall has decreased. That’s left snowshoe hares—which molt from brown to white with the seasons and glide over the snow on large feet—increasingly vulnerable to predators such as lynx, coyotes, bobcats, weasels, and birds of prey.

What’s a rabbit to do? One option is to chase after diminishing snow—and that’s what snowshoe hares are doing, say researchers at the University of Wisconsin–Madison.

Researchers have found that Wisconsin’s snowshoe hare population has shifted northward 18 miles since 1980, averaging five and a half miles every 10 years.

Because the hares are a critical part of the food web of northern forests, their disappearance could cause a domino effect that harms other wildlife, according to a study published in the journal Proceedings of the Royal Society B.

The snowshoe hare’s northward migration also suggests that the impact of burning fossil fuels—the leading cause of climate change—has surpassed development as the main driver of ecological change.

“In Wisconsin 100 years ago, lots of forests were cleared for habitation, and hares shifted north. But in the last 50 years, the forest cover hasn’t changed, but winter climate has changed dramatically,” said wildlife ecologist Sean Sultaire, a coauthor of the study.

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Winter temperatures in the state have risen by 3.5 to 4.5 degrees Fahrenheit since 1950, according to the Wisconsin Initiative on Climate Change.

“Snow is coming later and melting earlier, which is placing pressure on the snowshoe hares,” Sultaire said. “Their predators will lose an important part of their diet, and whether they can adapt to a different diet—we don’t know.”

As part of the study, Sultaire and his colleagues surveyed 126 sites in Wisconsin known to have supported snowshoe hares. They found them in only 28 of those areas, suggesting that the hare’s range in the state may have diminished by 78 percent.

Sultaire said his team’s data show that the state has had 10 percent less snow cover over the last five years and 19 fewer days of snow compared with 30 years ago.

“Climate change is less perceptible for people in daily life,” he said. “But we can see drastic impacts with some of these species through habitat fragmentation and loss.”