Warming Winters and the Regional Implications for the Subnivean Climate

Jonathan Pauli, Benjamin Zuckerberg, Warren Porter and Brian McMahon

Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, jnpauli@wisc.edu, bzuckerberg@wisc.edu
Department of Zoology, University of Wisconsin-Madison, wpporter@wisc.edu
Operation Fresh Start, Madison, Wisconsin, bmcmahon@operationfreshstart.org

Many plants and animals use the stable environment underneath the snowpack, called the subnivium, as a refuge from harsh winter weather. The depth, density, and duration of the snowpack determine the climatic conditions of the subnivium, which are typically much milder due to the insulation provided by the snow. As climate change produces warmer mean temperatures, however, the subnivium becomes colder and more thermally variable. These changing conditions can have significant effects on the physiology, survival, and distribution of species that are dependent on this habitat. Using micro-greenhouses that are automated to maintain set temperature gradients and allow winter precipitation to fall inside, we will assess how changing snow conditions affect the temperature and stability of the subnivium microclimate. In the fall of 2015, we deployed 27 greenhouses to nine sites representing conifer forests, deciduous forests, and open prairies. At the UWM Field Station, we have set up three microgreenhouses in a conifer stand. While we are still in the early stages of our research, we have begun to collect data on the climate conditions within and outside each greenhouse and will be continuing this research through the winter of 2017. Funded by the National Science Foundation.