1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Urumqi 830001, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Key Laboratory for Resource Use and Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
4. Agricultural Engineering, Integrated Polytechnic Regional College, Gishari, Rwamagana P.O. Box 60, Rwanda