1. State Key Laboratory of Vegetation and Environmental Change; Institute of Botany; Chinese Academy of Sciences; Xiangshan Beijing 100093 China
2. University of Chinese Academy of Sciences; Yuquanlu Beijing 100049 China
3. Department of Ecology; College of Urban and Environmental Science; Peking University; Beijing 100871 China
4. Research Group of Plant and Vegetation Ecology; Department of Biology; University of Antwerp; Wilrijk B-2610 Belgium
5. The Ecosystem Center; Marine Biological Laboratory; Woods Hole MA 02543 USA