1. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
2. State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University , Beijing 100875 , China
3. School of Geographic and Oceanographic Sciences, Nanjing University , Nanjing 210023 , China
4. College of Geography and Environmental Sciences, Zhejiang Normal University , Jinhua 321004 , China
5. Department of Environmental and Geographical Science, University of Cape Town , Rondebosch 7701, South Africa