Integrated Landscape Ecology Evaluation Based on RS/GIS of Three-Gorge Area
MENG Jijun 1) SHEN Wenming 2) WU Xiuqin 3) ( 1)Key Lab of Analysis and Simulation of Earth Surface Processes of Ministry of Education; Department of Geography, College of Environmental Sciences, Peking University,Beijing,100871; 2)Environmental information center, Sino-Japan Friendship Centre for Environmental Protection, Beijing,100029; 3)College of Soil and Water Conservation, Beijing Forestry University,Beijing,100083)
Based on RS and GIS techniques, a integrated evaluation model of eco-environment quality is developed according to Landsat TM images, NOAA/AVHRR data, DEM and eco-environment background of moisture and temperature. Seven indices are selected in the model. They are accumulated temperature greater than 0?℃,annual precipitation, altitude, slope, soil erosion, land use and vegetation index. Based on these,the author evaluates the eco-environment quality of Three-Gorges area,which is an ecological fragile region. The results show that (1) the eco-environment quality of Three-Gorges area is not quite good. The eco-environment quality at third,fourth and fifth grade occupies 74.54% of the total area. (2) The horizontal distribution of the eco-environment quality presentes evident regional differences. The eco-environment quality is the best at the end of the reservoir area. That in the beginning of the reservoir area takes the second place and in the middle of the reservoir area,the eco-environment quality is the worst. As far as the administration is concerned, the eco-environment of Yichang City, Changshou County,Chongqing City, Jiangjin County and Yichang County is good. While in Wuxi County,Yunyang County,Fengjie County,Shizhu County,Kai Couty, Wulong County,Wushan County and Wanzhou,the eco-environment is relatively bad. (3) The vertical differences of eco-environment quality are evident. The topography symbolized by slope is the main reason of causing these differences. The eco-environment quality is the worst in the region of middle altitude (500-2 000?m), which is mainly at fifth and sixth grade. While, in the region of low altitude (200?m), the eco-environment quality is the best. The quality at fifth grade occupies less than 1% of the total area. In the region of high altitude (2 000?m),though there are not many impacts of human,the steep terrain makes the eco-environment below fourth grade occupied 27% of the total area.