1. Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
2. Institute of Forage and Grassland Sciences Heilongjiang Academy of Agricultural Sciences Harbin China
3. Qinghai Academy of Animal Science and Veterinary Medicine Qinghai University Xining China
4. Eastern Forest Environmental Threat Assessment Center US Department of Agriculture Forest ServiceResearch Triangle Park NC USA
5. Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA