1Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, USA
2Pronatura Noroeste, San Luis Rio Colorado, Mexico
3Centro de Investigacion en Alimentacion y Desarrollo, Guaymas, Sonora, Mexico
4Department of Geosciences, University of Arizona, Tucson, AZ, USA
5ICESE, Department of Geology, CICESE, P.O. Box 434843, San Diego, CA 92143, USA