1. Department of Geography, University of California, Santa Barbara, CA 93106-4060, USA
2. Environmental Studies Program, University of California, Santa Barbara, CA 93106-4160, USA
3. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Villa de Etla, Oaxaca 68200, Mexico
4. Department of Community Health Sciences, UCLA Fielding School of Public Health, Los Angeles, CA 90095, USA