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. School of Life Science, Nanchang University , Nanchang 330031 , China
4. College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University , Beijing 100871 , China