Small Watershed Ecosystem Health Evaluation In Three Gorges Reservoir Area

Ecological environment is the basic condition of human survival and social and economic development. Maintain a healthy ecosystem and promote a virtuous circle of the ecological system are important issue which is related to human survival and health. Therefore, ecosystem health evaluation gets more and more attentions. Ecosystem health assessment can provide the basis of formulating scientific ecological system protection strategies, and it is important to ensure the health development of ecological system. The state of the watershed ecosystem is closely related to the human, social, economic and ecological environment. In recent years, along with the deterioration of ecological environment, the watershed ecosystem health assessment has become one of the hot researches by scholars at home and abroad.Taking the Wanjiagou small watershed in FuLing District as the study object, basing on PSR model, remote sensing imaging and statistical survey data, using GIS and Remote sensing technology, the paper established an evaluation index system which includes12indexes:population density, human disturbance index, fertilize employing intensity, pesticide employing intensity,>25°slope proportion of arable land, land reclamation index, carbon density, landscape diversity index, vegetation coverage, ecological elasticity, soil-water erosion intensity and the per capita annual net income. Then, the paper separately obtained Wangjiagou small watershed ecosystem health evaluation results in2002and2011by adopting the matter-element extension analysis method. And through the comparative analysis, we can find the main influence factors and the develop trends of the small watershed ecosystem. The results indicate as follows:1. The comprehensive correlation coefficient of the Small watershed ecosystem health evaluation has been increased from-0.0301in2002to-0.0235in2011. The comprehensive correlation coefficient of Pressure has been up from-0.0435in2011to-0.0231in2002; the comprehensive correlation coefficient of State has been rise from0.0172in2002to0.0435in2011; the comprehensive correlation coefficient of Response has gone up from0.0076in2002to0.0128in2011.2. Comparative analysis shows that in these10years, the status of the small watershed ecosystem has been significantly improved. There are different degrees of improvement in Pressure, State and Response, and Response of individual and social is the most significant on the level of evaluation, which shows that the state and local government attaches great importance to the ecological environment of the small watershed health s, and the ecological and environmental protection measures implemented has achieved good results. At the same time, it must be noticed that, as a predominantly agricultural area, Wangjiagou small watershed has more people and less land, its pressure station is still severe, especially the pressure caused by human. Therefore, correctly guiding famers developing and utilizing watershed resources rationally, reducing the pressure of human activities on ecosystems become the focus of government work.3. On the basis of the main ecological problems in Wangjiagou small watershed, combined with the author s study in ecosystem health assessment, this paper argues that the small watershed ecosystem health management should be strengthened mainly from four aspects:the implementation of the national policy and local governments’ advocacy work, the status of scientific research, the quality of workers and the economic development.