1. Department of Ecology; College of Urban and Environmental Sciences; Peking University; No.5 Yiheyuan Road 100871 Beijing China
2. Department of Biology; University of Antwerp; Universiteitsplein1 B-2610 Wilrijk Belgium
3. Institute of Tibetan Plateau Research; Chinese Academy of Sciences; 100085 Beijing China
4. Chair of Ecoclimatology; Technische Universität München; Freising Germany