Effects of Restoration Measures on Vegetation Features of Alpine Degraded Grassland of Amdo County in Tibet

Agpoyron trachyeaulun L.,Elymus nutans Griseb,Bromus inermis Layss and Poa crymophila Keng were reseeded in fenced areas using no-tillage.Vegetation height,coverage and grass yield were studied in order to reveal the effects of different restoration measures for vegetation characters,underground biomass,seed bank and diversity of Amdo in a typical degraded meadow in Tibet.Results showed that vegetation height,coverage and grass yield improved after no-tillage reseeded and fenced.Plant diversities increased slightly while there were significant differences among dominant species.Further,changes were seen in underground biomass of plant communities.Biomass of 0~10 cm soil layer ascended dramatically after fenced and reseeded.Additionally,the numbers of seeds in both fenced and reseeded plots were greater outside the fence and distributed mainly within 0~5 cm soil layer.