1. Department of Biology; University of New Mexico; Albuquerque New Mexico 87131 USA
2. Department of Earth and Planetary Sciences; Johns Hopkins University; Baltimore Maryland 21218 USA
3. Center for Limnology; University of Wisconsin-Madison; Madison Wisconsin 53706 USA
4. Environmental Studies Program and Department of Biology; University of Oregon; Eugene Oregon 97403 USA
5. Department of Biology; University of North Carolina Greensboro; Greensboro North Carolina 27402 USA
6. Smithsonian Environmental Research Center; Edgewater Maryland 21037 USA
7. Department of Wildlife, Fish and Conservation Biology; University of California; Davis California 95616 USA
8. National Ecological Observatory Network; Boulder Colorado 80301 USA
9. Biology Department; Reed College; Portland Oregon 97202 USA
10. The Arnold Arboretum of Harvard University; Boston Massachusetts 02130 USA
11. Department of Integrative Biology; University of Wisconsin-Madison; Madison Wisconsin 53706 USA
12. Department of Botany and Plant Sciences; University of California; Riverside California 92521 USA
13. National Center for Ecological Analysis and Synthesis; 735 State Street, Suite 300 Santa Barbara California 93101 USA