1. Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University , Kunming 650504 , China
2. School of Architecture and Civil Engineering, Xihua University , Chengdu 610039 , China
3. South-East Tibetan Plateau Station for integrated observation and research of alpine environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China