1. School of Land Science and Space Planning, Hebei GEO University, Shijiazhuang 050031, China
2. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
3. School of Resource and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
4. School of Ecology, Hainan University, Haikou 570228, China
5. School of Earth and Ocean Science, University of Victoria, Victoria, BC V8P 5C2, Canada