Ecological security evaluation in farming-pastoral ecotone using TM data

Farming-pastoral zone is one of typical ecological transition zone in China. To monitor and evaluate the ecological security in farming-pastoral zone is of great significance for regional environmental protection and rational utilization. This paper chooses Guyuan County as the research area, which is in typical farming-pastoral zone area named Bashang in north China. Then, in the administrative divisions of villages and towns, a comprehensive evaluation index of ecological security at small scale in Guyuan County is set up through the following steps. Firstly, based on the "Pressure - State - Response" (PSR) framework and according to the relationship between each component object, a multi-level evaluation index system is constructed. Then, TM remote sensing images, digital elevation data and statistical data are comprehensive utilized to calculate every evaluation index. Next, index weight is obtained by using the Analytic Hierarchy Process (AHP). Results show that the range of comprehensive evaluation index of ecological security in Guyuan County was 0.28-0.64. At most areas, the ecological security was at the "warning" level. At the minority areas, the ecological security even reaches "dangerous" level, such as Huanggaizhuo and Gaoshanbao. The worst town is Guyuan pasture. This study analyzed the ecological security in the region, provided a decision-making basis for the ecological protection.