1. Department of Ecosystem Science and Management, Pennsylvania State University, 117 Forest Resources Building, University Park, PA 16802, USA
2. Department of Biological Sciences, University of Alaska, Anchorage, 3101 Science Circle, Anchorage, AK 99508, USA
3. Department of Biology and Wildlife, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK 99775, USA
4. Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK 99775, USA