1. Department of Ecosystem Science and Management; Texas A&M University; 2138 TAMU College Station Texas 77843 USA
2. USDA-ARS; Jornada Experimental Range and Jornada Basin LTER; New Mexico State University; MSC 3JER, P.O. Box 3003 Las Cruces New Mexico 88003-0003 USA
3. USDA-NRCS; Jornada Experimental Range; MSC 3JER, P.O. Box 3003 Las Cruces New Mexico 88003-0003 USA
4. Department of Environment and Society; Utah State University; 5215 Old Main Hills Logan Utah 84322-5212 USA
5. Department of Ecosystems Science & Management; University of Wyoming; Agriculture Building 2013, Dept 3354 Laramie Wyoming 82071 USA
6. Wyoming Agricultural Experiment Station; University of Wyoming; 1000E University Avenue, Dept 3354 Laramie Wyoming 82071 USA