1. Department of Wildland Resources Utah State University Logan UT 84322 U.S.A.
2. The Ecology Center Utah State University Logan UT 84322 U.S.A.
3. Department of Natural Resources and Environmental Science University of Nevada, Reno 1664 N. Virginia Street Reno NV 89557 U.S.A.
4. Rangeland Resources and Systems Research Unit USDA‐ARS 1701 Centre Avenue Fort Collins CO 80526 U.S.A.
5. Department of Plant Sciences University of California Davis CA 95616 U.S.A.
6. School of Natural Resources and the Environment University of Arizona Tucson AZ 85721 U.S.A.