1. State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China
2. Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang Cele 848300 Xinjiang China
3. Key Laboratory of Biogeography and Bioresource in Arid Land Chinese Academy of Sciences Urumqi 830011 China
4. School of Ecosystem and Forest Sciences University of Melbourne 500 Yarra Boulevard 3121 Richmond Vic Australia