Lu Zhang1, Jiazi Liu1, Dajun Wang1, Hao Wang1, Yonglin Wu2, Zhi Lü3. 1. Center for Nature and Society, School of Life Science, Peking University, Beijing, 100871, China. 2. Qinghai Lake Nature Reserve, Xining, 810008, China. 3. Center for Nature and Society, School of Life Science, Peking University, Beijing, 100871, China. luzhi@pku.edu.cn.