A Study On The Evaluation Of Urban Ecosystem Health Based On Circular Economy

As the product of social, economic and cultural development, city is an embodied social-economic-natural complex ecosystem. At present, China is in the phase of rapid urbanization, the strong demand for constructing modern nation, intensive land development activities, large-scale infrastructure construction, high material consumption and high pollution-based industries, which help to improve the local economic development and also bring a series of serious negative effects such as resources depletion, environmental pollution, ecological degradation, and public health endangrous. In a word, the city has highlighted the unhealthy symptoms. To sovle the urban ecological problems, stop the deterioration of ecological environment and improve the resource utilization efficiency, have become the focus of most countries in the world. Therefore, it is very meaningful, significant and urgent to study the evolution mechanism of Urban Ecosystem Health.This paper revolves around the urban ecosystem health assessment, starts with the circular economy, and uses the methodology named Set Pair to enrich the study on the theory, method and practice research of urban ecosystem health assessment by taking Lanzhou City as an example, and it conducts active attempt to establish the index system and apply the research methods.The first chapter introduces the concept of urban ecosystem health content and the basic theory of circular economy. The second chapter reviews the research progress and outcomes by domestic and foreign scholars in the field of urban ecosystem health assessment, and expounded on China's urban ecosystem health assessment of the characteristics different from the West. The third chapter establishes the assessment index system based on the concept of circular economy consisting of productivity power, living status, ecological ascendancy and vital force, which represents the situation of urban economic subsystems, social subsystem, natural subsystem, and ecological regulatory subsystem. This paper uses the methodology named Set Pair to establish the analysical model, and finally finds out a method including index system, index weight, and evalution method. In chapter four, Lanzhou was studied as a case to identify the states of its urban ecosystem health from 2000 to 2009, and to analyze the key factors which effect the ecological development, and predict the developmental trend of urban ecosystem health of Lanzhou from 2010 to 2015. In chapter five, suggestions which aim to improve the urban ecosystem health for encouraging sustainable development are proposed. At last, the sixth chapter presents the conclusions.In brief, the paper incorporates the index system of circular economy in the urban ecosystem health assessment, which not only fully respects and reflects the feature of urban ecosystem health assessment in the new phase of development, but also improves the research techniques and methodology of urban ecosystem health assessment. The conclusion recommends the priority areas of ecological construction for the Lanzhou urban planning, and provides decision making basis for the sustainable development of Lanzhou City.