Research Center of Contemporary Ecoenvironmental Geology, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037,China; 2. Association for Sustainable Ecological and Socio-Economic Development in Poor Areas of Yenching Alumni, Beijing 100045,China; 3. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, Shandong, China; 4. Institute of International Studies, Tsinghua University, Beijing 100084, China; 5. Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; 6. College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China; 7. Institute of Hydrogeology and Environmental Geology, Shijiazhuang 050061, Hebei, China