The Urban Ecological Security Assessment Of Yangtze River Delta Urban Agglomerations

As the increase of population and the development of economy, the environmental pressure is becoming more and more intense. The human life has been impacted more severely by the issues of environmental damage and ecological deterioration. Ecological security issues have been paid more and more attention by scholars and government, and become the hot topics in the academic field.Based on domestic and abroad research accomplishments on ecological security, this paper constructs the urban ecological security evaluation indexes system of the Yangtze River Delta urban agglomerations by using the PSR (pressure-state-response)" theoretical model from three aspects, which are the system pressure, the system status and the system response. The entropy weight method has been used to weight the indexes. Finally, the fozzy comprehensive evaluation method and the comprehensive index evaluation method are used to evaluate the ecological security of the Yangtze River Delta urban agglomerations both vertically and horizontally. The results are as follows:(1)The horizontal evaluation result of the16cities in2012shows that the urban ecological security are all above the critical safety level. The ranking by using the method of fuzzy comprehensive evaluation is Ningbo, Suzhou, Zhenjiang, Wuxi, Changzhou, Yangzhou, Taizhou, Huzhou, Nantong, Zhoushan, Hangzhou, Nanjing, Shanghai, Taizhou, Shaoxing, Jiaxing. In addition, the ranking by using the method of comprehensive index evaluation is Ningbo, Wuxi, Suzhou, Changzhou, Zhenjiang, Yangzhou, Zhoushan, Huzhou, Taizhou, Nantong, Hangzhou, Shanghai, Taizhou, Nanjing, Shaoxing, Jiaxing. Obviously, the two kinds of evaluation results are basically identical. The methods are proved to be feasible.(2) The longitudinal evaluation result of the16cities in2001-2012shows that the ecological security level of the16cities increased year by year. By using the average of the ecological security eigenvalue in12years this paper makes a ranking on the16cities, which is Ningbo, Suzhou, Changzhou, Wuxi, Zhenjiang, Yangzhou, Huzhou, Zhoushan, Nantong, Taizhou, Hangzhou, Taizhou, Shanghai, Nanjing, Shaoxing, Jiaxing.Through the further analysis, ten indexes which have the greatest contribution to ecological security level were found out, that are s5-coverage rate of afforestation in developed area,r6-the standard discharge rate of industrial wastewater, rl-environmental protection investment as a share of GDP, r8-the utilization rate of solid waste, s3-per capita public green areas, r7-urban sewage treatment, p4-the intensity of industrial soot emissions per ten thousand Yuan GDP, r5-the number of high school students per ten thousand people, p5-the intensity of COD emission per ten thousand Yuan GDP, s1-forest coverage rate.(3)Considering the status of ecological security of the Yangtze River Delta urban agglomerations and the influences, this paper proposed countermeasures accordingly, that are formulating a scientific and reasonable city planning, developing the circular economy, improving urban greening coverage, perfecting the system of ecological safety guarantee system, conducting all-national environmental education et al..