Division on degraded succession series of alpine grassland in Big Yourdusi Basin

In the present study, the degraded succession series of Stipa purpurea in alpine grassland was classified using system clustering analysis in Yourdusi Bayanbulak, and grassland plant community structures with different degraded level were compared. With the increase of the grassland degradation succession degree, the plants community structure and the dominant position of the main plants obviously changed and the height, coverage, density and the above ground biomass of S. purpurea decreased. The degradation succession model of alpine grassland in Bayanbulak were S. purpurea+Koeleria→Leymus+Potentilla→Carex+Pedicularis→Koeleria+Potentilla. The important value of S. purpurea was as an important index of grassland degradation in Yourdusi Bayanbulak. The similarity between samples from same level was higher while similarity between samples from different levels was lower. Clustering results consistent with various similarity comparison results.