| Duolun county of Inner Mongolia is an important part of north grasslands stepped sandy land in China. Since the end of 1990s, there had been large change in its ecological environment. The types of good forage reducing and the area of desert increasing induced this area becoming one of sources of sandstorm in the north of China.This paper researched on the situation of vegetation and Human-induced vegetation restoration regions, analyzed the floristic of seed plants in this area and the relationship of plant community in the degenerated grassland with the environment. And the author investigated on the effect of Human-induced vegetation restoration and rangeland close to foster and the influence of human-plant to the plant diversity in Duolun county of Inner Mongolia. The above things which the author did are to provide scientific proof for the protection of plant diversity and vegetation restoration in Duolun county. The paper made these following conclusions.1. The flora of Duolun County consists of 465 species and 245 genera belonging to 75 families, these species respectively take 21.1%, 37.5%. and 64.1% of the all wild seed plants in Inner Mongolia. But the area of Duolun only takes 0.33% of the whole Inner Mongolia area. Focusing the research on plant distribution, we will know that the plants'distribution in temperate zone is dominant in Duolun County. The geographical composition in temperate zone is complex and excessive. And there is some age-old composition but lacking of special elements in this zone.2. Eight types of communities were classified with the DCCA method and plant diversity by analysis. These were communitiesâ… (Achnatherum splendens)+( Puccinellia tenuiflora), communityâ…¡(Artemisia frigida)+(Agropyron cristatum), communityâ…¢(Agropyron cristatum)+(Cleistogenes squarrosa), communityâ…£(Stipa grandis) +(Artemisia frigida), communityâ…¤(Carix spp.)+(Stellera chamaejasme), communityâ…¥(Salix gordejevii)+(Artemisia halodendron), communityâ…¦(Ostryopsis davidiana) + (Spiraea aquilegifolia), communityâ…§Mixed grasses in man-made forest. These communities and the distribution area standed for the patterns of communities in this area. By making regression analysis of plant diversity, it was proved that there is closed connection between species diversity and their environment factors.3. By analysis of the relationship between plant and acreage, 10 m2 of sample area is better in this field. The values of Melilotoides ruthenica, Agropyron cristatum, Cleistogenes squarrosa and Leymus chinensis is higher than the control area in experiment station, which indicates that our management in programs have effectively improved the environment of degraded grassland and restored the vegetation to some extent; The values of Carex spp, Corispermum spp, Setaria viridis, Psammochloa villosa, Allium prostratum, Agriophyllum squarrosum is lower than the control area in experiment station, which indicates that the environment of grassland in uncontrolled area is severely degraded. Therefore, human-induced vegetation restoration is concluded that not only controlling soil erosion but also increasing species richness in the representative area.4. The experiment results for closing the degenerated rangeland in Duolun County showed, once degenerated rangeland was closed, the coverage and the height and the forage production of the vegetation in rangeland increased respectively 37.5%, 150%, 160% than open period. But with close period is continued, the increase tendency of the coverage and the height and the forage production of the vegetation in rangeland has dropped. In view of comprehensive thought of ecology and economic, the reasonable close period for degenerated rangeland is about 5 years.5. To construct plantation in grassland areas would not result in the biodiversity and herbages biomass remarkable decrease. It has something to do with plantations species, but has little something with herbaceous species variety.
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