| Land is the material basis of social development and national economy,land ecological environment problems will directly affect the sustainable development of the region.In recent years,Although China has strengthened the construction of ecological civilization,it has not fundamentally solved the problems of soil erosion and soil denudation.Ecological environment sensitivity assessment is the precondition of ecological function regionalization.It is also an important means to judge the stability of ecosystem.The sensitivity evaluation of land ecological environment is the implementation of Scientific Outlook on Development and the concept of ecological civilization,an important measure to speed up the implementation of the main functional area planning and construction of the national ecological security barrier,which is of great significance to promote the sustainable development of Longnan city and safeguard the national ecological security.Based on the basic characteristics of mountainous ecosystem in Longnan City,this paper uses GIS technology to develop single factor evaluation and comprehensive evaluation of land ecological sensitivity from three aspects of soil erosion,rocky desertification and geological disasters,and to extract the dominant factors,Research on spatial distribution of comprehensive evaluation results by correlation method.Dominant factor was extracted and the spatial distribution characteristics of the comprehensive evaluation results was studied by spatial autocorrelation method.Evaluation results show:(1)the difference of land ecological sensitivity in Longnan is obvious.The East is higher than the West in the east-west direction and present decreasing trend.In the north and south direction present a obvious "n" font,slightly higher than the northern part of the south,slightly higher in the South than in the North;(2)Using the natural breakpoint method,the land ecological sensitivity of Longnan was divided into the extremely sensitive area,the highly sensitive area,the middle sensitive area.The low sensitive area and the insensitive area accounted for 23.58% of the total area of the city 26.22%,24.46%,15.63% and 10.12% respectively;the extremely sensitive area and the highly sensitive area is mainly distributed in the surrounding area of Tanchang county and Wudu area etc.The ecological sensitivity of the area is very strong,needing to strengthen the protection,the development intensity should not be too high;Low sensitive and non sensitive areas are mainly distributed in most of the areas of Li County,West County,Hui County,which can be appropriate for development.(3)using IDL to extract the limiting factors of ecological sensitivity in Longnan,the results showed that the proportion of rocky desertification was the highest,accounting for 53.55% of the total land area.Longnan city soil erosion distribution area,mainly distributed in the city of Longnan in the central region and the western region from concentrated distribution;Geological hazards,as a limiting factor accounted for 33.74% of the total land area,mainly distributed in the low altitude area and the concentration of residential areas in the valley of the eastern region of Longnan;Soil erosion,as the limiting factor of ecological sensitivity,accounts for 12.71% of the total land area,and is mainly distributed in the area with high human disturbance and high precipitation.(4)using GeoDa software to calculate the ecological sensitivity of Longnan Moran value of 0.5525,it shows that there is a certain positive correlation and aggregation in the regional distribution of ecological sensitivity.The H-H and L-L types of 26 and 31 towns were obtained by local spatial autocorrelation analysis,accounted for 13.27% and 15.82% of the total number of villages and towns in Longnan respectively;Negative correlation type H-L has 1 village,accounted for 0.51% of the total number of villages and towns in the region.There are 0 types of L-H;There are non-significant type of 138 townships,accounting for the proportion of 70.41%. |
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