1. Department of Geography & Earth Sciences, University of North Carolina, Charlotte, Colvard 5062, Charlotte, NC 28223, USA;
2. Department of Biology, Sonoma State University, Rohnert Park, CA 94928, USA;
3. Present address: Department of Environmental Science and Policy, 1 Shields Avenue, University of California, Davis, CA 95616, USA
4. Department of Environmental Science Policy & Management, 137 Mulford Hall, University of California, Berkeley, CA 94720, USA;