Rising Temperatures and Retreating Snow Cover May Lead to The Extinction of Many Species

In a new study, researchers have discovered that rising temperatures throughout the North Hemisphere may result in a significant loss of snow cover, and in turn endanger many of the species that rely on it to survive through the winter.

The snow cover is vital to many animals and plants who use it as insulation in order to endure the harsh temperatures. This phenomenon is known as the "subnivium," referring to the seasonal micro-environment that exists beneath the snow. This layer provides warmth, consistent humidity levels, and protection from the wind; and the depletion of the needed snow cover is causing many species to face potential extinction.

"Underneath that homogenous blanket of snow is an incredibly stable refuge where the vast majority of organisms persist through the winter," says study co-author Jonathan Pauli. "The snow holds in heat radiating from the ground, plants photosynthesize, and it's a haven for insects, reptiles, amphibians and many other organisms."

Pauli is a UW-Madison professor of forest and wildlife ecology.

"There are thresholds beyond which some organisms just won't be able to make a living," Pauli adds. "The subnivium provides a stable environment, but it is also extremely delicate. Once that snow melts, things can change radically."

"The winter ecology of Wisconsin and the Upper Midwest is changing," says his colleague Benjamin Zuckerberg, also a UW-Madison professor of forest and wildlife ecology. "There is concern these winter ecosystems could change dramatically over the next several years."

According to the news release, among those most affected will be "reptiles and amphibians, which can survive being frozen solid, [but] are put at risk when temperatures fluctuate, bringing them prematurely out of their winter torpor only to be lashed by late spring storms or big drops in temperature.

"Insects also undergo phases of freeze tolerance and the migrating birds that depend on invertebrates as a food staple may find the cupboard bare when the protective snow cover goes missing."

The researchers warn that much of the region's plant life, and in effect, the entire ecosystem, may be in danger.

"Snow cover is becoming shorter, thinner and less predictable," Pauli concludes. "We're seeing a trend. The subnivium is in retreat."

The study was published in the journal Frontiers in Ecology and the Environment.