1. College of Geographic Science, Inner Mongolia Normal University, Hohhot 010022, China
2. College of Resources and Environment, Baotou Teachers’ College, Science and Technology University of Inner Mongolia, Baotou 014030, China
3. Inner Mongolia Key Laboratory of Remote Sensing and Geographic Information Systems, Inner Mongolia Normal University, Hohhot 010022, China
4. School of Environment, Northeast Normal University, Changchun 130024, China
5. Key Laboratory for Vegetation Ecology, Ministry of Education, Changchun 130024, China