The Study On Evaluation And Distribution Of Eco-environmental Sensitivity In The Middle And Lower Reaches Of Che'erchen River

Eco-environmental sensitivity is a degree which reflects the changes of natural environment and interference from human activity on ecosystem. It shows the degree of possibility and speed of restoration of the ecological imbalance and eco-environmental problems in a region. Eco-environmental sensitivity is a comprehensive index which evaluates the eco-environmental quality, rational utilization of water and soil resources and population and economic development in a region. It shows the degree of sensitivity of the ecological system reflected in a variety of environmental variations and the responses of human activities and it is used to reflect the degree of possibility of ecological imbalance and eco-environmental problems. Evaluation of eco-environmental sensitivity plays an important role on analyzing the stability of the regional ecological system and determining the key points of the protection and restoration of the ecosystem. Due to adverse natural environment, the fragile ecological conditions, the large area reclamation and the irrational use water resources, in the middle and lower basin, especially the middle reaches, there have been emerged many ecological environment problems recently such as land desertification, soil salinization, woodland reduced, grassland degradation, sandstorms disasters, biodiversity reduced, and so on. The research object of this paper is ecological environment sensitivity of watershed and the core is to study the spatial structure and function of ecological environment in the basin. Based on the characteristics of the typical arid and semi-arid basin, we extracted the middle and lower reaches basin from the big river basin reasonably, established eco-environmental sensitivity evaluation System and the single-factor and multi-factor comprehensive evaluation models, we combined methods of remote sensing, geographical information systems and mathematics to evaluate the ecological environment sensitivity in this basin comprehensively using remote sensing images of 1980,1995,2000 and spatial data of 1km×1km grid water and land resources and spatial superposition analysis module of geographic information systems software which make the ecological environment sensitive area demonstrated in space. Based on the research findings we divide this region into five major ecological function areas, such as soil and water conservation and protection area in Che'erchen River delta, sandy wind control area in the plain in the middle reaches, biodiversity conservation area in downstream plains, the region of desert, the Gobi area of the southern piedmont, based on different features and functions of the areas we put forward the development and protection measures scientifically and rationally.