1. State Key Laboratory of Vegetation and Environmental Change; Institute of Botany; Chinese Academy of Sciences; Beijing 100093 China
2. University of Chinese Academy of Sciences; Beijing 100049 China
3. Inner Mongolia University of Technology; Inner Mongolia 010051 China
4. Department of Ecology, and Key Laboratory for Earth Surface Processes of the Ministry of Education; Peking University; Beijing 100871 China
5. Key Laboratory of Ecosystem Network Observation and Modeling; Institute of Geographical Sciences and Natural Resources Research; Chinese Academy of Sciences; Beijing 100101 China
6. Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 3UU UK