1. Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia Univ., 235 West University St., Hohhot, Inner Mongolia 010021, China.
2. Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia Univ., Hohhot, Inner Mongolia 010021, China; Institute of Environmental Geology, Inner Mongolia Univ., 235 West University St., Hohhot, Inner Mongolia 010021, China (corresponding author).
3. Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia Univ., Hohhot, Inner Mongolia 010021, China; Associate Professor, Institute of Environmental Geology, Inner Mongolia Univ., 235 West University St., Hohhot, Inner Mongolia 010021, China.
4. Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia Univ., Hohhot, Inner Mongolia 010021, China; Professor, Institute of Environmental Geology, Inner Mongolia Univ., 235 West University St., Hohhot, Inner Mongolia 010021, China.