1. Key Laboratory of Molecular Epigenetics of Ministry of Education, Key Laboratory of Vegetation Ecology, Ministry of Education, School of Life Sciences, Northeast Normal University, Changchun 130024, People’s Republic of China
2. Key Laboratory of Grassland Resources, Ministry of Education P.R. of China, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of Ministry of Agriculture, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China
3. Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China