Abstract: Investigating the response law of the main plant population and community characteristics of desert steppe to grazing use patterns can not only elucidate the change law of the plant community in desert steppe, but also can explore the change characteristics and rules of the main plant population as an important part of the desert steppe community. The combination of the above two aspects is conductive to grasp the variations in the structure and function of the plant community in desert steppe. In this study, the Stipa breviflora desert steppe in Sonid Right Banner of Inner Mongolia was used as the research object. A total of 6 grazing treatments were set up and arranged in random blocks (3 blocks, 3 repeats). The main plant population (Stipa breviflora, Cleistogenes songorica and Allium polyrhizum) as well as the height, coverage, density and existing stocks of the plant community were used as evaluating indicators to assess the relational order of the main plant populations and communities among different grazing treatments and grazing seasons by using optimal parent sequence correlation degree analysis. The results showed that the SA1 treatment mode of rest grazing in spring + heavy grazing in summer + moderate grazing in autumn was recommended as the first choice for sustainable grassland use, followed by the SA5 treatment mode of moderate grazing throughout the whole year. Furthermore, the optimal parent sequence correlation degree analysis method exhibited simplicity and convenience in grassland evaluation.

Key words: desert steppe, main plant population, plant community, optimal parent sequence