| VOver the past 40 years of reform and opening up,the Chinese urbanization has developed rapidlyand has achieved a series of world-renowned achievements in various fields of the economy and society.At the same time,the issues such as water and soil pollution,air pollution,resource depletion,and ecological damage continue to be exposed,the Chinese urban social and economic development has paid a great deal of resources and environmental costs.Therefore,it is particularly important to carry out quantitative research on sustainable development.The ecological carrying capacity,as an important indicator of measuring the sustainable development of regional economic,social and ecological environments,and an important basis for judging the level of regional sustainable development,it can comprehensively and roundly reflect the carrying capacity of urban complex ecosystem,and complementing the quantitative study of sustainable development.The urban agglomeration in the middle reaches of the Yangtze River is located in the central region of China,as a rapid urbanization area and hot spot where the contradiction between social and economic development and resources and environment is more prominent,it has typicality to research urban ecological carrying capacity.Therefore,carrying out quantitative assessment and analysis of influencing factors on the urban ecological carrying capacity of the region,clarifying the development stages and constraints of the regional urban ecological carrying capacity,and formulating recommendations for urban ecological carrying capacity improvement based on the above premise,which will be useful for the sustainable development of the urban agglomerations in the middle reaches of the Yangtze River and even the entire country.The thesis is divided into three parts: The first part,firstly refers to and summarizes the relevant research results on urban ecological carrying capacity,defines the concept and connotation of urbanecological carrying capacity,and builds the comprehensive evaluation index system of urban ecological carrying capacity on the basis of a deep understanding of the connotation of urban ecological carrying capacity,which includes four subsystem layers of social development,economic development,supportive capacity of resources and environment and ecological resilience,as well as nine criteria layers and twenty-seven specific indicators,using entropy method and state-space techniques to measure the current values and ideal values of urban ecological carrying capacity of urban areas in the middle reaches of the Yangtze River from 2006 to 2015,and determines the carrying status of urban ecosystems in different cities.The second part respectively analyzes the carrying status of urban ecosystems in urban agglomerations and the characteristics of spatio-temporal pattern evolution of the four subsystems carrying status,and using regression analysis method and the gray correlation analysis method to analyze the influencing factors of urban agglomeration and the influencing factors of each type of ecological bearing zone.The third part is to analyze the characteristics of the overall temporal and spatial pattern of the comprehensive cities' ecological carrying capacity system and four subsystems and the characteristics of the spatial-temporal pattern evolution of the ministry,and the results of the overall influencing factors of urban ecological carrying capacity and the associated influencing factors of each ecological bearing type area,and suggest countermeasures and suggestions to the future development of the urban ecological carrying capacity of urban agglomerations in the middle reaches of the Yangtze River from the perspective of the overall and subdivided areas.The findings are as follows:(1)From the perspective on the comprehensive development trend of the urban ecological carrying capacity of urban agglomerations and the carrying capacity of various subsystems,the current values of urban ecological carrying capacity of the cities in the middle reaches of the Yangtze River in the period from 2006 to 2015 shows a general trend of fluctuation and decline,but the vast majority of citiesare still in an overloaded state;the change characteristics of the current values of four subsystems carrying capacity vary from 2006 to 2015,in which the temporal change characteristics of the resource-environment subsystem and the ecosystem elasticity subsystem are similar to the temporal evolution characteristics of the urban ecosystem capacity system,the current values of the carrying capacity of the social development subsystem shows a trend of decreasing after the fluctuations first,and the current values of the carrying capacity of the economic development subsystem shows a trend of increasing first and then decreasing.(2)From the perspective on the spatial evolution characteristics of the urban carrying capacity of urban agglomerations and the spatial evolution characteristics of the carrying capacity of various subsystems,the light and moderately overloaded regions present the status of scattered point and are mainly distributed in the central and eastern regions of the urban agglomeration.During the study period,there was a trend of continuous expansion into the central and western parts of the urban agglomeration.The heavily overloaded areas mainly present crumby structure or band structure and widely distribute in most parts of the urban agglomerations.During the study period,the type of distribution area has a tendency to the retreat of the north-south boundary of the urban agglomerations;From the perspective of subsystems,the spatial pattern evolution of the carrying capacity of the ecological elastic system is roughly the same as the spatial pattern evolution of the carrying capacity of the urban ecosystem,which the characteristics of spatial patterns of other subsystems are different.(3)From the perspective of the characteristics of spatial correlation of the urban carrying capacity of urban agglomerations,the current values of urban ecological carrying capacity of urban agglomerations in the middle reaches of the Yangtze River in the period of 2006-2015 have significant characteristics of high-value gathering and low-value gathering in space and the spatial agglomeration is still increasing.From the perspective of local correlation characteristics,the Getis-Ord Gi* index value of the currentvalues of the urban ecological carrying capacity of urban agglomerations in the middle reaches of the Yangtze River during the period from 2006 to 2015 shows the spatial distribution characteristics of “central part is high,four weeks are low”;The number of hot areas and Sub hot areas shows a trend of fluctuating and rising,indicating that the agglomeration range of high value areas shows a trend of expanding,and the gathering trend of high value centers tends to be significant during the study period.From the point of the spatial migration characteristics of cold areas and hot areas,there are a trend of hot areas migrating from the middle of the urban agglomeration to the northeast and then migrating to the middle east hot spots during the study period,the cold spots have a tendency to migrate from the north of the agglomerations to the northwest,which is consistent with the spatial evolution characteristics of the urban ecosystems.(4)From the analysis of influencing factors,we can see that in terms of the overall influencing factors of urban agglomeration,the factors such as household consumption level factors,ecological environmental protection concept,and economic development efficiency factors have a significant positive impact on the improvement of urban ecosystem carrying status.The natural resources condition factors have a significant negative impact on the improvement of urban ecosystem carrying status,in which the positive impact of ecological environmental protection concept factors on urban ecological carrying status is further deepened during the study period,and the negative impact of the natural resources condition factors negatively on the urban ecological carrying status has increased to some extend.In terms of influencing factors in different types of areas,ecological environmental protection concept factors,scientific and technological development level factors and social stability factors have a significant effect on enhancing the ecological carrying capacity of urban ecosystem-carrying cities,while the population carrying pressure has a significant negative effect on this type of cities.The impact factors of the cities with mild overload area and moderate overload area are basically the same,through analyzing and finding thatthe social stability factors,the level of environmental pollution treatment and the efficiency of economic development have a significant positive promoting impact on the promotion of the ecological carrying capacity of these two types of cities,these two types of areas are mainly distributed the cities where is along the rivers and lakes in the central area urban agglomerations of the middle reaches of the Yangtze River;There are significant positive relationships among the heavy overloaded cities and these three factors of the efficiency of economic development,the level of environmental pollution treatment and the level of technological development,which this type of city is mainly distributed in the northern and southern urban agglomerations of the middle reaches of the Yangtze River and economic development with high energy consumption,large environmental pollution,low scientific and technological content in industry,and poor governance of the ecological environment are common problems existing in the type cities.In addition,a series of negative issues need to be paid more attention,such a lagging process of urbanization of rural population and urban and rural dual structure highlights which caused by the process of rapid promotion of population urbanization in this type of cities. |
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