Abstract: Grazing disturbs grassland environment through gnawing and treading of livestock, which changes species composition and population's dominant. This study showed that the species richness in communities gradually decreased with the aggravating of grazing intensity from saline moist meadows to typical steppe communities. The measurement of β diversity showed that on saline moist meadows, the intermediate disturbance of species change occurred during the course of light to moderate grazing stage, with a low stability during the whole grazing; while on meadow steppes and typical steppes, it occurred during the course of moderate to heavy grazing stage. Desert steppe showed a high stability throughout grazing system, and the species change from light to over grazing was only 1～3. The stability of grassland community diversity was as follows: desert steppe>typical steppe≥meadow steppe>saline-moist meadow.

Key words: Grassland community, Grazing disturbance, β-diversity, Intermediate disturbance, Stability, trade-off, Saussurea przewalskii, reproductive characteristics, altitude, individual size