| Exclusion, as a main kind of measure to vegetation restoration and reconstruction in sandy area, has been wide use in many countries. Exclusion vegetation zone of oasis peripheral is organic part of oasis peripheral ecological protection safety guarantee system and first defendant line, and has important buffer and resistance role to sand fixation and containment desertification of oasis.The research take fencing sandy land of oasis peripheral in jingtai county as object, which is in southern margin of Tengger Desert, applying the ecological restoration theory and method, investigate and analysis vegetation characteristics difference between natural vegetation enclosure and artificial cultivation +enclosure in fixed position. And taken moving sandy land +non-enclosure as the control. The results indicate as follow:1)By artificial cultivation and continuous 15 years exclusion and vegetation succession, in artificial cultivation +enclosure,species richness of plant community increased to 18 species, in which perennial herbs had 6 species,and community was dominated shrubs of artificial cultivation, such as Artemisia desertorum Spreng., Caragana intermedia Kuang et H.C.Fu, Hedysarum scoparium Fisch. et Mey. and so on. In herb layer, the invade species was mainly annual herbaceous, such as Salsola collina Pall., Corispermum patelliforme Iljin., Bassia dasyphylla (Fisch. et C. A. Mey.) O. Kuntze and so on. While, in natural vegetation enclosure, after continuous enclosing 15 years and vegetation succession, species richness of plant community has reached to 24 species, in which perennial herbs has 11 species, accounting for 61.11 percents in the herb species numbers. And dominated species was Artemisia arenaria DC., Artemisia scoparia Waldst.et Kit., Salsola collina Pall., Bassia dasyphylla (Fisch. et C. A. Mey.) O. Kuntze, Stipa bungeana Trin. and so on. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, plant species richness of the two exclusion patterns were greatly increased and species dominance had happened significantly changed.2) In community life forms, invade species of artificial cultivation +enclosure was dominated annual herbaceous, but natural vegetation enclosure was dominated perennial herbs and semishrub. The structure of life forms was significant difference between the two exclusion patterns. In families and genera compositions, artificial cultivation +enclosure was dominated leguminosae, compositae and chenopodiaceae, and their species numbers has little difference compared with other families. But natural vegetation enclosure was dominated compositae in species numbers, and families and genera species was richer than artificial cultivation +enclosure, but the species numbers of families each has larger difference. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, community stability of the two exclusion patterns was greatly improved and families and genera compositions had changed complication.3) The variance analysis result of plant density was shown that herb density has significantly different in natural vegetation enclosure, but in artificial cultivation +enclosure, shrub and herb density, dominated Artemisia arenaria DC. density and all plant density had no obvious difference. The variance analysis result of vegetation coverage and growth characteristics was shown that shrub and herb crown width coverage, projective coverage and average plant height and dominated species average ground diameter had little difference between each quadrats in artificial cultivation +enclosure or natural vegetation enclosure. But shrub crown width coverage, average plant height and herb average plant height had greatly difference(p<0.01), projective coverage of herb and crown width coverage of dominated Artemisia arenaria DC. had difference between the two exclusion pattern(sp<0.05), however average ground diameter and average plant height of dominated Artemisia arenaria DC. has no obvious difference. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, plant density and vegetation coverage and growth characteristics of the two exclusion patterns was greatly improved .4) The changed range of above-ground total biomass were 251.99 g·m-2 from 261.64 g·m-2 in the two exclusion patterns, which indicated that effect of exclusion patterns to above-ground total biomass of plant community had no obvious difference. But in natural vegetation enclosure, spatial variability of biomass was higher, and herb above-ground total biomass was also higher than artificial cultivation +enclosure. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, the two exclusion patterns can greatly improved above-ground total biomass of plant community. 5) The effect of exclusion patterns to Shannon index and richness index of herb layer had great, excepted the other indexes. Compared with natural vegetation enclosure, diversity index and evenness index of herb layer were obvious lower, but Simpson ecological dominance index was higher in artificial cultivation +enclosure, which indicated that the community stability of artificial cultivation +enclosure was far inferior to natural vegetation enclosure. However, in shrub layer, ecological dominance index of natural vegetation enclosure was higher than artificial cultivation +enclosure. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, the two exclusion patterns can greatly improve plant community diversity restoration. 6) The result of niche analysis showed that in shrub layer, Artemisia arenaria DC. had the widest niche breadth, followed by Nitraria tangutorum Bobr. in natural vegetation enclosure. In artificial cultivation +enclosure, Artemisia arenaria DC. had the widest niche breadth, followed by Caragana korshinskii Kom. and Hedysarum scoparium Fisch. et Mey. In Grass layer: in natural vegetation enclosure,Artemisia scoparia Waldst.et Kit. had the widest niche breadth, followed by Salsola collina Pall. In artificial cultivation +enclosure, Salsola collina Pall. had the widest niche breadth, followed by Corispermum patelliforme Iljin. In artificial cultivation +enclosure, shrub layer, Caragana korshinskii Kom. and Hedysarum scoparium Fisch. et Mey. had largest niche overlap. In herb layer, Salsola collina Pall. and Corispermum patelliforme Iljin. had largest niche overlap, followed by Bassia dasyphylla (Fisch. et C. A. Mey.) O. Kuntze. In natural vegetation enclosure, Artemisia arenaria DC.and Nitraria tangutorum Bobr., Caragana roborovskyi Kom. and Artemisia sphaerocephala krasch. had largest niche overlap, in herb layer, Artemisia scoparia Waldst.et Kit. and Salsola collina Pall. had largest niche overlap, followed by Salsola collina Pall.and Bassia dasyphylla (Fisch. et C. A. Mey.) O. Kuntze. It showed that niche breadth of same species was different in the two exclusion patterns, and dominated species had largest niche overlap, plant species which had wide niche breadth had also large niche overlap, but niche overlap between same species disaccord in the two exclusion patterns. Compared with moving sandy land+non-enclosure of vegetation sprinkling distribution, the two exclusion patterns can greatly improve capacity of sand species resources utilization and play of niche function, meanwhile, which also enhanced competition degree of species capacity to resources utilization.7) The similarity index indicated that there had middle similarity between each quadrats in artificial cultivation +enclosure, and the similarity between each quadrats of natural vegetation enclosure was lower than artificial cultivation +enclosure. The community similarity index indicated that ecological distance between artificial cultivation +enclosure and natural vegetation enclosure was still far, and ecological distances between the two exclusion patterns and moving sandy land+non-enclosure of vegetation sprinkling distribution were significantly far.
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