Abstract: The structure and function of natural vegetation in special habitat of transition zone is different, so an oasis-desert ecotone in southern marginal zone of the Junggar Basin in Xinjiang was selected as our study area. The species composition and distribution of natural vegetation and its windproof effect in this area in early spring were studied. The results are as follows: (1) After analyzing the species composition and distribution of natural vegetation in all the sample plots, it was found that the natural vegetation in the ecotone is dominated by shrubs no matter from the species number or coverage, and Haloxylon ammodendron acts as its construction species. In addition, the indexes of species richness, species diversity and species evenness are quite different from the different regions. (2) After carrying out the linear correlation analysis among the average height and coverage of natural vegetation and its relief amplitude and average wind speed at two heights (0.5 m and 1.5 m) from the ground, it was found that there is only an extremely significant correlation between relief amplitude and average wind speed at two heights, and the average wind speed at two heights is decreased with the increase of average height and coverage of natural vegetation. (3) Based on the Wasson and Nanninga’s first modeling idea, a mathematical model between natural vegetation coverage and relative wind speed was developed using Matlab software, it was found that there is a negative exponential function between them. It was predicted that the windproof effect of natural vegetation can be up to 60% when the coverage of effective vegetation higher than 0.5 m reaches 23.16%; The windproof effect of natural vegetation can reach 50% when the coverage of effective vegetation higher than 1.5 m is 36.33%.

Key words: oasis-desert ecotone, early spring, natural vegetation, species composition, windproof effect, Junggar Basin