In order to reveal its effectiveness as an ecological restoration measure and the state of community succession， this study took the vegetation of a desert steppe in Inner Mongolia enclosed for 22 years as the research object. And the effect differences of long-term enclosure on plant community species diversity， species niche characteristics， and interspecific associations were compared and analyzed between the enclosed site and the control site. The main results showed that under the enclosure treatment， the number of plant community species， the Margalef diversity index， the Shannon-Wiener diversity index， the Simpson richness index， and the Pielou evenness index all increased significantly. The important value and niche breadth of perennial herbs increased significantly， while the important value and niche breadth of degradation indicator species such as Neopallasia pectinata decreased significantly. The number of plant species pairs with niche overlap values greater than 0.2 and 0.5 increased to varying degrees. Interspecific association analysis based on the Pearson correlation coefficient， the interspecific association coefficient AC test， and the Spearman rank correlation test indicated that the overall interspecific association in the plant community of the enclosed site showed a non-significant negative correlation and the interspecific associations were weak. In conclusion， long-term enclosure significantly increased plant diversity in the desert steppe， optimized species composition， and improved plant utilization efficiency of environmental resources. However， the weak interspecific associations and the non-significant negative overall correlation indicate that the community is still in an unstable successional stage after 22 years of enclosure， and its long-term stability and restoration effectiveness require further attention.

Desert steppe  /  Enclosure  /  Important values  /  Ecological niche  /  Interspecific associations