To clarify the effects of different grazing intensities on the plant community structure， species diversity， and population niche characteristics in desert steppe， reveal the laws of community species replacement and the niche response mechanisms of dominant species， and provide a theoretical basis for scientific grazing management， this study set up four different grazing treatments to analyze changes in community species composition， diversity， and niche characteristics. The results showed that with the increase of grazing intensity， the community species shifted from perennial forbs and shrubs/subshrubs to perennial grasses； grazing significantly reduced the total aboveground biomass of the community and the biomass of various functional groups， and the Shannon-Wiener index， Simpson index， and species richness index. Stipa breviflora， Cleistogenes songorica， and Convolvulus ammannii maintained a wide niche breadth under all grazing treatments， and the niche overlap among species with high niche breadth was generally high， with the niche overlap between Stipa breviflora and Cleistogenes songorica reaching the highest under the heavy grazing treatment. The study indicated that grazing significantly affected the structure of desert steppe communities by altering the resource competition relationships among species. Therefore， grazing intensity should be controlled in desert steppe management to maintain ecosystem stability.

Desert grassland  /  Important value  /  Functional groups  /  Niche width  /  Niche overlap