1. Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Resources, Chengdu 610041, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. College of Management, Sichuan Agricultural University, Chengdu 611130, China
4. Sichuan Center for Rural Development Research, College of Management, Sichuan Agricultural University, Chengdu 611130, China