Evaluation On Regional Ecological Security Based On GIS And RS

The rapid development of economic promotes the progress of human society and human civilization. However, when the human satisfy their own material and spiritual enjoyment, a series of problems of ecological security occur one after another. In Foreign, the human begin to focus on the problems of ecological security from the 1970s, however, in domestic, the human begin to do it until the late 1990s. In recent years, the study on the ecological security increases obviously. At present, the study on ecological security has become a hot spot at home and abroad.Yinchuan is the capital of Ningxia's province. With the fast development of eomomic, Yinchuan has become one of the leading cities in Northwest China. However, Yinchuan City is located in Northwest Arid Region of China, which has following characteristics:the scarcity of rain and snow, strong evaporation, dry climate, strong wind, more sand and so on. There are some problems, such as land desertification, soil salinization, sandstorm, water shortages and other issues. So, the ecological environment of Yinchuan is fragile. So it is necessary to comprehensively evaluate the eclogical security level of Yinchuan city. It is hepeful to guide the construction of Yinchuan environmental protection and ecological security.The basic theory of ecological security, research status and research methods were summarized in this thesis. The ecological security assessment index system of Yinchuan was established based on PSR model. The information of the ecological security assessment index was extracted by using RS and GIS technology. The ecological security evaluation database of Yinchuan City was established. And then, the level of ecological security of Yinchuan was evaluated based on the constant weight and the variable weight average additive synthesis model. At last, some ecological security control measures were made. The main conclusions were as follows:(1)Based on evaluating the level of ecological security of Yinchuan by using the constant weight and the variable weight average additive synthesis model,we found that the result obtained by using the variable weight average additive synthesis model was more practical.(2)The ecological security of Yinchuan was mainly of lower and general level. They accounted for 68.17% of the total area of Yinchuan. The proportion of the lowerer level was 38.77%, and the area was 3704.05km2. The proportion of the general level was 29.4%, and the area was 2809.35km2. The proportion of the higher level was 11.66%, and the area was 1113.84km2. The proportion of the lowest level was 20.18%, and the area was 1927.75km2. There was no the highest level in Yinchuan.(3)The whole level of ecological security of Yinchuan was mainly the lower. The level of ecological security of Linhe Town was the highest, which was 6.47. The level of ecological security of Daxin Town was the lowest, which was 2.74. The ecological security of local villages and towns were mainly the lowest and lower level, which accounted for 13 and 9 respectively. The number of the general level was 5.(4)Considering the evaluation results and the contributing factors, the idea of the graded control of ecological security was proposed. Yinchuan City was divided into four zones:The first control zone was largely concentrated in urban areas and transport lines. The second control zone was largely concentrated in both sides of irrigation district and the central of Lingwu. The third control zone was largely concentrated in the Helan Mountains piedmont alluvial plain sloping, east of the Yellow River alluvial plain and the northern and southern parts of Lingwu City. The fourth control zone was largely concentrated in Helan Mountain Natural Reserve, Bletilla Beach Natural Reserve. At last, some control measures of ecological security were proposed to different graded control zones. In addition, some special control measures were made for construction of Ningdong Energy Chemical Base.