Abstract: This paper examined the effects of enclosure management on the structure of community in degraded sandy grasslands. Several conclusions were drawn from this study. (1)The coverage, density, aboveground biomass and average height of the fencing grassland were all superior to those of the grazing grassland, and there was a significant different(P<0.01). Compared with the grazing grassland, coverage of the fencing grassland increased by 237%, density, height and aboveground biomass respectively increased by 429%, 77% and 218%. The structure of community was significantly improved by enclosure. (2) Compared with the grazing grassland, the species of the fenced grassland increased by 69%. Species and important values of perennial herbs and shrubs in the fencing grassland were higher than the grazing grassland. The dominant species of grazing grassland were Corispermum macrocarpum, Setaria viridis and Artemisia halodendron, the ration of important value accounted for 72%. Lespedeza davurica, Cleistogenes squarrosa, Chloris virgate and Eragrostis pilosa were the dominant species of fencing grassland, their important value accounted for 57%. In the fencing grassland, the largest families were Leguminosa and Gramineae plants, which were adapted to their growing environment. C. macrocarpum, S. viridis and A. halodendron were gradually in a secondary status. By enclosure, Species composition of the community was diversified, the structure and function were improved,and desertification of sandy grasslands was restored. (3) The Shannon-Wiener index, Simpson index, Margalef index and evenness index of the fencing grassland were all larger than those of the grazing grassland. Enclosure increased the species diversity and stability of community.

Key words: degraded sandy grasslands, enclosure, grazing, community structure, function