1. Department of Biology, Case Western Reserve University, Cleveland, Ohio 44106
2. Department of Mathematics and Statistics, Williams College, Williamstown, Massachusetts 01267
3. Department of Environmental Science and Policy, University of California, Davis, California 95616
4. Santa Fe Institute, Santa Fe, New Mexico 87501
5. Cornell Lab of Ornithology, Cornell University, Ithaca, New York 14850
6. Hastings Natural History Reservation, University of California, Berkeley, Carmel Valley, California 93924
7. USDA Forest Service Northern Research Station, Morgantown, West Virginia 26505
8. Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Praha 6–Suchdol, Czech Republic
9. Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003