Development of a Spatio-Temporal Snowpack Model for use in Assessing 
Changes in Mammal Distributions in Wisconsin
Jason E. Bruggeman*, University of Minnesota, MN   
James E. Woodford, Wisconsin Department of Natural Resources, WI  
David E. Andersen, University of Minnesota, MN 

In northern latitudes, a range of abiotic processes influences mammal distributions and, 
ultimately, population dynamics. Snow is a particularly important factor in these ecosystems 
because of its potential impacts on animal energetics and forage accessibility. However, 
relatively little has been documented regarding how long-term changes in snowpack impact 
mammal distributions on fine spatial scales. Therefore, we gathered snow and precipitation 
data from 308 National Climate Data Center climate stations throughout Wisconsin and 
developed a GIS database of spatial and temporal trends in snowpack dating back to the 
mid-twentieth century. We developed regression models, consisting of habitat and 
topography covariates, to help understand factors affecting snowpack at each station. Using 
information theoretic methods we selected the best approximating model and applied it to 
estimate snowpack properties between climate stations throughout Wisconsin where no 
data existed. We then analyzed historic distribution data for fisher (Martes pennanti) and 
marten (Martes americana) populations in Wisconsin in relation to snowpack properties. 
Our work provides an understanding of how these medium-sized carnivores alter their use 
of the landscape based on snowpack dynamics and interspecific competition.
*Presenter