Scientists Make Urgent Plea for Better Understanding of How Changing Snowscapes Affect Arctic Wildlife
A pair of polar bears in Alaska pause in the snow. More detailed snow research data could benefit these and other animals, researchers say.
For nine months every year, snow dominates the Arctic tundra and forests of the far north. Animals trudge through deep fields of it, scrape it from rocks to find nibbles of sustenance, seek shelter from the cold in hollowed-out drifts and camouflage their winter fur in its whiteness. Their quality of life depends on how much snow falls, what kind of snow it is, where it blows, how it turns to slush and refreezes.
While those snow features are likely changing dramatically as Arctic warming outpaces that of any other region on Earth, no one can say with certainty what’s actually happening to the snow—and by extension, the animals that live in it. That’s because the data needed for such an assessment are almost nonexistent.
A paper published this month in the journal Environmental Research Letters, co-authored by a researcher in the Department of Biology, urges government agencies and scientists to make immediate investments in specialized snow data that can improve wildlife ecology and management in the Arctic.
“Much of what we know about snow in the Arctic comes from remote observations from satellites,” said Eliezer Gurarie, an associate research scientist in biology. “What we can see from space leaves us with questions about what it means on the ground. Knowing where the snow is isn’t enough.”
But detailed information is rarely available. According to the study, the density of ground-based Arctic observation stations is one-eighth of that found in 10 states in the western contiguous United States.
Remote observations, mostly from satellites, provide coverage, but usually on too large a scale to be useful for wildlife studies. Features that affect wildlife may occur across an area of just a few meters, while satellites tend to capture multi-kilometer-scale data.
For Gurarie, a quantitative wildlife ecologist who studies caribou migrations, that means unanswered questions about the conditions that trigger the animals’ spring migration, the longest overland migration in the world. Culturally and economically important to the people of the Arctic, caribou travel thousands of miles every year across a frozen landscape of bogs, rivers and mountains.
Changing conditions are threatening that journey. The study found little correlation between when snowmelt occurs—observable with satellites—and when the migration begins. But the researchers' ongoing studies have shown that the quality of snow affects caribou movement. Rain and refreezing events that create hard ice layers have often prevented the animals from foraging and even led to catastrophic die-offs.
The authors also examined what kinds of data are needed for better study of polar bears and Dall sheep. Polar bears, for instance, require deep, fluffy snow drifts for dens. Increased rain and refreeze events create icy layers and reduce insulating properties of snowpack, limiting the bears’ den options.
Among the investments needed to address the lack of Arctic and boreal data, the authors call for more collaboration between the agencies and organizations that study the regions. They urge immediate action to gather more specialized data such as snow depth, density, hardness and collapse pressure. They also recommend more ground-based monitoring stations and greater use of animal-mounted cameras and sensors to add to and validate remotely collected data. The approach also incorporates satellite monitoring and enhanced computer models to make use of the new data.
“The Arctic and boreal region are home to some of the last remaining pristine areas on the planet with intact wildlife communities,” Gurarie said. “We need to make a concerted effort to understand the effect of climate change on this region, and wildlife biologists, satellite data scientists and snow physicists all have to learn to communicate with each other and tackle these problems jointly. There is definitely momentum building for the kinds of interdisciplinary collaboration that we are calling for.”
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