The Spatial Distribution Of Vegetation Types In Shaanxi Province

The terrain conditions of Shaanxi Province are extremely complicated, with a variety of plant species and vegetation types. this peper used the 1:1000000 vegetation map(1996) of Shaanxi Province which was compiled by Lei Mingde. Shaanxi province was divided into 4 districts: the north and the south of northern Shaanxi, Guanzhong and South Shaanxi area. Using the approach of point coverage to investigate and research the distribution area of various vegetation types, the data gained were analyzed by utilizing β-distribution model, Proved the spatial distribution of vegetation in Shaanxi Province and the relationship between it and distribution area, together with the vegetation composition and diversity. And verify that the frequency distribution of four areas in accordance with the Raunkiaer′s law.The main conclusions obtained are as follows:(1) All the density function of vegetation coverage of four areas in Shaanxi province match β-distribution model, The model can be used to calculate the spatial heterogeneity of vegetation index value quantitatively.(2) The decreasing spatial heterogeneity index of the vegetation in the four regions was Guanzhong area > South Shaanxi area>the North of Northern Shaanxi > the South of Northern Shaanxi. What’s more, with the decreasing of the spatial heterogeneity index.(3)There was an increasing tendency of vegetation distribution area(cover degree). The south of northern Shaanxi and South Shaanxi area were significantly higher than the north of northern Shaanxi(p<0.01)in terms of the average variety index of vegetation, while the north of northern Shaanxi was significantly higher than Guanzhong area(p<0.01)(4)The frequency distribution of the North of Northern Shaanxi was A > B > D > C, It was not following the Raunkiaer′s law, with the uneven distribution of community types, And only in Northern Shaanxi appeared vegetation of D frequency level; The frequency distribution in Southern Shaanxi and Southern Shaanxi was A > B > C, The frequency distribution of Guanzhong area was A > B, Almost following the Raunkiaer′s law. The distribution of vegetation types was homogeneous.