1. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650091, China
4. Baotou Teachers’ College, Inner Mongolia University of Science & Technology, Baotou 014030, China