Studyon Eco-Environmentfragile Evaluation Of Typical Karsthilly County

Ecological environment, a general term to the quantity and quality of water resources, land resources, biological resources and climate resources that influence human survival and development, is a compound ecosystem related to the sustainable development of the society and economy. Due to the pressure of population quantity and unrestrained demanding from and emission into the nature, ecological environment, the material foundation of human survival and development, suffers a gradual weakening of self-adjusting ability, and thus shows a trend of being fragile, which has resulted in a variety of ecological problems. Ecological environment vulnerability assessment is actually the assessment of the degree to which the population, the production, the social development and the overall environment can produce or will produce. It also a comprehensive measure criterium for whether the environment can keep a sustainable and stable availability. Based on an understanding of special attributes of each element of the environment and the overall effect of the combination of elements, and the scope and the evolution trend of fragile ecological environment, combining with a comprehensive analysis of the causes of fragile ecological environment and the environmental receptors, the present research,by a quantitative and semi-quantitative method, aims to achieving a generalization of fragile ecological environment as a whole.The present research, taking Chongqing Tujia and Miao autonomous county as the research object, mainly adopts multi-source data, includingaerial photograph ofYouyang(in2009), topography map (plotted in1991, Beijing coordinate system), geological map, the map of geological disaster, the map of soil type, the map of land cover and lithologic map, to work out the thematic data of the study area, and selects9vulnerability assessment factors on the aspects of geology, soil erosion, vegetation cover, land use, soil and others to establish assessment system. The weight assignment are done according to the analytic hierarchy process (AHP), in combination with matrix, and then superposition and interpolation are done within the ArcGIS software platform, and thus the map of YouYang ecological vulnerability is achieved, which is then exemplified from the perspective of space distribution and the distribution of towns. Finally, based on the present situation of ecology, economy and society in Youyang Tujia and Miao autonomous county, reasonable suggestions and ideas are presented for the harmonious development of ecology and economy or society.The research results are as follows:(1) The score of ecological vulnerability in Youyang Tujia and Miao autonomous county is between1.349and4.708, and five grades are defined according to arithmetic principle. Moderate vulnerable area and mild vulnerable area are most widely distributed in Youyang Tujia and Miao autonomous county which account for about90%of the whole area. In eastern area, environmental quality is better than that in middle and western area and moderate vulnerable area and mild vulnerable area are most widely distributed in the east where potentially vulnerable areas are mainly distributed, especially in the northeast, In Youyang Tujia and Miao autonomous county, environmental quality in middle and western area is, from the whole, relatively poor, forming a zone of highly vulnerable ecological environment which is roughly like Chinese character "人", while ecological environment in the northwest and southwest is relatively good. Ecological environment in some parts of southwestern area is seriously bad, and in the south, highly vulnerable area is also widely distributed.(2) In terms of towns, highly vulnerable area and extremely vulnerable area are largely in towns in the midwest, including Flower Field Town, Livable Town, Tonggu town, Guanqing Town, the north of Blackwater Town, the middle and south of River Town, the west of Nanmu Town, the southwest of Longtan Town, the north and southwest of Lixi Town, the south of Houping Town and the north of Cangling Town. Also, a large number are distributed in Miaoxi Town, Gongtan Town, Tianguan Town, Two Zeng Town, Dingshi Town, Spring Town and Shuangquan Town.Highly vulnerable area and extremely vulnerable area in Tonggu Town, Houping Town, town, Lixi Town, Blackwater Town, Livable Town, Guanqing Town, Flower Field Town, Longtan Town, Shangri-la Town, River Town, Nanmu Town, Cangling Town, Banxi Town and Dingshi Town, are all up to over1000hm2and in Tonggu Town is as high as4161.33hm2Twelve towns where highly vulnerable area and extremely vulnerable area account for over10%, are Guanqing Town (up to36%), Tonggu Town, Flower Field Town, River Town, Livable Town, Lixi Town, Blackwater Town, Na Yao Jie Town and Slab Bridge Town. The ecological environment in these towns is so serious that it deserves much attention and active management.