1. State Key Laboratory of Vegetation and Environmental Change; Institute of Botany; Chinese Academy of Sciences; Beijing 100093 China
2. Department of Plant Pathology; North Carolina State University; Raleigh NC 27695-7616 USA
3. Department of Geography and Geology; Eastern Michigan University; Ypsilanti MI 48197 USA
4. Department of Vegetation Ecology; Institute of Botany; Mongolian Academy of Sciences; Ulaanbaatar-51 Mongolia