1. Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA.
2. Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2753, Australia.
3. Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA.
4. Department of Biology, University of Wisconsin, Eau Claire, WI 54701, USA.