1 Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, United States.
2 Plant Ecology Research Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.
3 Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, Lausanne, Switzerland.
4 Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.
5 U. S. Geological Survey, Southwest Biological Science Center, Moab, UT, United States.