1. Department of Natural Resources Conservation, 160 Holdsworth Way, University of Massachusetts, Amherst, MA 01003‐9285, U.S.A.
2. Department of Organismic Biology, Ecology, and Evolution, 621 Charles E. Young Drive South, Box 951606, University of California, Los Angeles, CA 90095‐1606, U.S.A.
3. Santa Monica Mountains National Recreation Area, National Park Service, 401 Hillcrest Drive, Thousand Oaks, CA 91360, U.S.A.