[1] US Fish & Wildlife Serv, Anchorage, AK 99503 USA
[2] US Fish & Wildlife Serv, Denver, CO 80225 USA
[3] US Geol Survey Forest, Boise, ID 83706 USA
[4] Rangeland Ecosyst Sci Ctr, Boise, ID 83706 USA
[5] Manomet Ctr Conservat Sci, Manomet, MA 02345 USA
[6] US Fish & Wildlife Serv, Arct Natl Wildlife Refuge, Fairbanks, AK 99701 USA