1 College of Grassland Science, Key Laboratory of Grassland Ecosystem of the Ministry of Education, Gansu Agricultural University, Lanzhou, Gansu, China.
2 Disturbance Ecology and Vegetation Dynamics, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth, Bavaria, Germany.
3 Department of Health & Environmental Sciences, Xi'an Jiaoting-Liverpool University, Suzhou, Jiangsu, China.