1. State Key Laboratory of Vegetation and Environmental Change; Institute of Botany; Chinese Academy of Sciences; 20 Nanxincun Xiangshan Beijing 100093 China
2. School of Forestry & Environmental Studies; Yale University; New Haven CT 06511 USA
3. Department of Evolution, Ecology, and Organismal Biology; The Ohio State University; Columbus OH 43210 USA
4. Smithsonian Tropical Research Institute; Box 0843-03092 Balboa Ancón Panama
5. Department of Ecology and Evolutionary Biology; University of California; Los Angeles CA 90095 USA