1. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco−Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China
3. Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
4. International Platform for Dryland Research and Education, Tottori University, Tottori 680-0001, Japan