Based On GIS The Ecological Security Assessment On The Middle And Lower Reaches Of Hanjiang River Basin

Ecological security refers to the health and sustainable development state of the ecology environment which the human's survival and development depend on. Supported by the spatial quantities analysis function of GIS and the application of ecological security assessment framework at the watershed scale, the paper establish the indicator system on the basis of research on ecological security concept and subsystems included by ecological security. On the support of GIS technology, the author build ecological security database using conventional maps and statistical data as data resources and establish the ecological security assessment model on the basis of quantities factors and analysis, in order to assess the ecological security condition in the middle and lower reaches of Hanjiang River Basin. In the whole process of assessment, there is not only comprehensive assessment but also single factor analysis, attempting to figure out the decisive factors which influence the research area. The study takes the watershed as the research scale and adopts grid unit and regional unit respectively to assess the ecological security condition of the research area, by this mean not only enhance the precision of the research but also make the assessment much more comprehensive, furthermore the paper try to provide exact information for the controllment on the harmony development between the various subsystems in the regional area. The state of ecological system is divided into 5 classes which range from the excellent to the poor. According to the basic condition and eco-environment problems of typical counties belonged to each class, the paper proposes some controlling measures pertinently. The thesis is divided into five parts as follows:The first part was production. It explained the paper research background; the present situation of domestic and foreign ecological security research; the research object; the research content; the research method.The second part introduced the concept and theories of ecological security and summed up indicator system, methodology and theories of the ecological security assessment in domestic and abroad.The third part was ecological security assessment modeling. By analyzing the existing ecological security theory and according to P-S-R conceptual framework, based on the principle of the selection of indicators, the paper selects 26 measure indicators from 3 basic elements of pressure factor, state factor and response factor. The ecological security index (P) defined as a measure index of regional ecological security is calculated by the mathematic model.The fourth part was a case study. Firstly, the basic profiles of study area were analyzed. Secondly, data source and data processing were introduced. The data processing included GIS database establishing, spatial interpolation and modeling. Thirdly ecological security scores of integrated index of pressure, state, response and ecological security index (P) were calculated by applying the assessment model. Finally the state of ecological system is analyzed and divided into 5 classes which range from the excellent to the poor. The paper adopts grid unit and regional unit respectively to assess the ecological security condition of the research area. The result shows that the change of P values presents an obvious trend that is P value gradually decreases in the direction from northwest to southeast. In the view of analyzing in regional unit, the state of ecological security in county area was much better than that in city area. The P values of Wuhan district and ShenNongjia districts are 0.3478 and 0.7941 respectively, representing the best and poorest ecological security condition districts among the study area.The sixth part was the conclusions and prospects. This part summarized the main results and conclusions of innovation, research and absence. Then the direction for further research was pointed out.