Study On The Characteristics Of Vegetation Community Undei Different Interference Conditions In Xilamuren Grassland

At the edge of the city,Xilamuren grassland was used intensity,and the ecological environment is extremely fragile.In recent years,the rapid development of tourism and the proliferation of animal husbandry,the trend of land degradation is serious.At the same time,land degradation in turn restricts economic development.So this situation formed a vicious circle.Based on the research of community characteristics and diversity index of the enclosed,grazing,and semi grazing area,this paper discusses the distribution of vegetation,get the following conclusion:1.There were 21 families and 51 species in the Xilamuren grassland.Gramineae,Compositae and Leguminosae had 10,6,4 species,Three of them had 51%of the total number of plant species.Stipa krylovii and Leymus chinensis were relatively important.Artemisia frigida had the highest value(14.11),by human disturbance and cattle and sheep grazing showed significant degradation in the free grazing area.Silver spirits compared to the enclosed area increased by 10.33,grassland degradation trend in the semi-free grazing area.The enclosure area is dominated by Stipa krylovii + Leymus chinensis,and the vegetation type is typical of the grassland.The semi-free grazing area is dominated by Stipa krylovii +Convolvulus ammanni,Stipa krylovii+ Artemisia frigida.2.The UPGMA phenotypic coefficient was 0.76,and the vegetation was divided into 10 groups by UPGMA.The environmental factors PCA sequencing reflects the change of soil nutrient from barren to rich,increasing soil water content,decreasing soil tightness and decreasing grazing intensity.The RDA sequencing indicates that the environmental factors that affect the community type of the grassland of the grass are the management mode and slope position.And the contribution rate of the two factors is 46.4%.3.In the enclosed area,from the top of the slope to the bottom of the slope,the dominant species showed a significant gradient change from Stipa krylovii to Stipa krylovii + Agropyron + Ley,mus chinensis and then Leymus chinensis The formation of grassland type,species degree,coverage and biomass gradually increased with the order of Koeleriaglauca + Bupleurum scorzonerifolium + Thymus mongolicus as the dominant species,and the increasing rate increased.The effect of slope position on free grazing area and free grazing area is reflected in the influence of height,coverage and biomass on the slope.Free grazing area,the height of the community,the coverage,the biomass as the enclosing area>semi-free grazing area>free grazing area,the height of the enclosed area is significantly higher than the grazing area and free grazing area(P<0.05).4.The species diversity index peaks appear in the cluster VI,which is distributed in the bottom water area of the enclosed area,and the superior hydrothermal condition makes it reach the peak value.The second wave is located at the top of the free grazing area,and the distribution of cattle and sheep does not like to eat the vegetations,less interference,and a diversity index with a high point of the enclosing area.The troughs of the troughs which are located at the top of the enclosed.The area has no human disturbance,natural wind erosion and water shortage,and the diversity index is R = 5.00;H? 1.30;D=0.68;J = 0.81.5.In the study of the best community environment,the proportion of the 22%of the enclosed was 50%,and the semi-free and free grazing area accounted for 30%and 20%respectively.The optimum community environment is located at the bottom of the semi-free grazing area,indicating that moderate disturbance has a positive effect on the environment.The enclosure has a good effect on the restoration of grassland vegetation.The free grazing area,the slope area is affected by overgrazing,Habitat is poor.