1. a School of Geography and Environment Project, Gannan Normal University, Ganzhou 341000, China
2. b School of Geography and Tourism & Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, Jiaying University, Meizhou, Guangdong 514015, China
3. c College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China