What’s happening to animals without their winter cover?
With increasingly warming temperatures in New England throughout the winter and little snow covering the ground, animals’ typical winter movements are beginning to look different. Many animals are forced to surface early from hibernation and others are facing difficulty without being able to camouflage with fresh layers of snow, which used to be a regular occurrence. Snow acts as a blanket for animals, keeping the ground from freezing. Without cover and insulation, animals are put at extreme risk.
Where are animals in the winter? Some are in the Subnivean Zone.
(from sub- + Latin niveus of snow + English -an)
The subnivean zone is the area between the bottom of the snowpack and the ground.
Not all animals hibernate, some are very active below the snowpack. Animals create a network of tunnels and chambers, and if the snow is deep enough, they create pathways to the surface for air. This in-between area development is supported by rocky areas and plants that create natural pathways within the snow. It doesn’t get fully created until there is a minimum of six to twelve inches of snow. With the first snow, small animals like mice start to burrow under the snow for protection from the cold and wind to find food. This zone is insulated from the extreme winter weather and warmed by the underlying earth. The weight of the snow begins to compress itself to keep heat from the ground trapped below. Food sources like insects will freeze solid if the snow is less than six inches, causing a food shortage for many animals.
How is this affecting our animals? With global warming and less snow in New England, the subnivean zone develops later in the fall or winter and disappears earlier in the spring. In southern New England, it may not even develop at all. This poses a threat to animals who are adapted to living in this layer. Without snow cover, these animals are now exposed to predators like coyotes and owls, and also find themselves in a struggle to locate food due to incredibly low temperatures. Along with this they may also freeze to death without the insulation this zone provides.
Jonathan Pauli, a biologist at the University of Wisconsin-Madison, has dedicated his studies to learning about the subnivean and the animals that live there. He has been worrying that climate change is going to affect this underground world in a number of ways. Pauli states, “The snowpack will be reduced, and snow density will increase.” Because warm air holds more moisture, snow—instead of being dry and fluffy—will become wet, dense and colder. Warmer temperatures lead to a chillier subnivean.” Even little changes that make this layer the smallest bit cooler could make it inhospitable to animals.
Check out these links to learn more!
http://www.thefieldguidespodcast.com/new-blog/tag/subnivean
Very interesting but at the same time very sad to learn the devastating effects of a lack of snowfall. Nature is so carefully balanced with everything in the ecosystem – including weather – working together, but changing something as simple as the amount of snowfall has such wide-ranging impacts.