1. College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
2. Department of Biology, Syracuse University, Syracuse, New York, USA
3. Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York, USA
4. Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
5. USDA Forest Service, Northern Research Station, Houghton, Michigan, USA
6. Institute of Arctic and Alpine Research, Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA