1. Department of Geography; The Pennsylvania State University; Walker Building University Park PA USA
2. National Center for Ecological Analysis and Synthesis; 735 State Street Santa Barbara CA 93101 USA
3. Department of Environmental Conservation; University of Massachusetts-Amherst; 160 Holdsworth Way Amherst MA 01003 USA
4. Environmental Studies Program & Department of Ecology; University of California-Santa Barbara, Evolution and Marine Biology; Santa Barbara CA 93106 USA
5. Department of Geography; National Centre for Earth Observation and University College London; Gower Street London WC1E 6BT UK