关键词: 降水改变, 多样性指数, 群落稳定性, 群落相似性, 植被群落

Abstract: Desert steppe vegetation characteristics are sensitive to precipitation changes, and researching the impact of precipitation changes on desert steppe vegetation characteristics has important ecological significance. This study took a typical desert grassland (agro-pastoral transition zone in the Mu Us sand area) of Yanchi County in Ningxia as the research object, and used canopy technology to simulate 33%, 66%, 100%, 133% and 166% of normal precipitation. Two years later, the response law of vegetation characteristics of desert steppe to changes in precipitation was discussed. The results showed that increasing precipitation increased the proportion of important values of legumes and grasses in the community; treatment of 166% precipitation reduced the height of the community and the coverage of the community; the important value of the community and the dryness of the litter weight, biomass, and density first increased and then decreased with the increase of precipitation; height, coverage and Margalef index were extremely significantly negatively correlated; Pielou, Simpson, Shannon-wienner index and community density, litter dry weight, above ground and underground biomass showed a very significant negative correlation (P < 0.05);the vegetation community under the treatment of natural precipitation was the most stable, and the similarity of the water-increasing treatment community was the least. This research aimed to explore the response strategies of desert grassland vegetation communities to changes in precipitation and provided a theoretical basis for grassland governance.

Key words: Precipitation change, Diversity index, Community stability, Community similarity, Plant community