Evolution Research Of Dry Valley And Ecological Security Evaluation Of The Upper Reaches In Minjiang River

The upper reaches of Minjiang River is the lifeline of Minjiang River drainage, and it is served as the ecological environmental barrier of Chengdu plain and the Yangtze River basin. Its ecological environmental quality and ecological security status are directly related to the sustainable development of Chengdu plain and Sichuan basin. Over the years, the deterioration of the natural environment and human activities had caused strong interference and destruction to ecological environment of the upper reaches of Minjiang River. Then, it led to the degradation of the environmental quality, and the ecological security.In the view of the unique regional characteristics in the upper reaches of Minjiang River, the gradually degraded natural environment as well as the gradually poignant contradiction between human needs and natural resources, the boundary of arid valley in the upper reaches of Minjiang River in 1994, 2001, 2007, 2009 and 2013 was extracted with the support of GIS and RS. The research Was based on the remote sensing data and other multi-source spatial data. Then the evolution characteristics of arid vally were analysed and studied. The result shows that the change of the dry valley is fluctuant, and it is obviously disturbed by human activities.This thesis uses analytic hierarchy process to build the evaluation index system for the ecological security of the upper reaches of Minjiang River, then determining the weight value of each index. Also it uses the comprehensive index method to calculate the ecological security index of evaluation unit in 2001 and 2009, then evaluating and analyzing the ecological security situation and the change characteristics before and after the earthquake of the upper reaches of Minjiang River. The result shows that the change of the ecological security situation in the upper reaches of Minjiang River trends to be good. Besides, the arid valley and the ecological security situation influence each other in space and features.Study the changes of ecological security and driving factors in the upper reaches of Minjiang River has guiding significance for managing and recovering the ecological environment in the upper reaches of Minjiang River and even the Yangtze River basin. It also provides fundamental and scientificreference in making decisions for socioeconomic development.