Industrial Pattern,Population Agglomeration,Spatial Spillover And City Ecological Efficiency In China

In recent years,with the rapid economic development and urbanization,the rapid expansion of urban population has expanded quickly.However,the extensive development of economics and the expansion of urban population caused great pressure on the urban environment,and a variety of environmental problems followed.The urban ecological problems are not only existed in the development of urbanization in our country,but also the concern to all countries in the world.For that reason,it is of great practical significance to study the ecological efficiency of cities and explore the inherent laws of ecological efficiency changes.The expansion of the city is also a process of spatial clustering of industry,population and cities,but the relevant research conclusions on the impact of relevant industrial agglomeration,population agglomeration and spatial spillover on urban ecological efficiency are controversial.Therefore,it is of great theoretical and practical significance to study the influence of industry,population and urban agglomeration on the ecological efficiency of cities and to explore the coordinated development path of economic growth and environmental protection.This paper analyzes the mechanism of agglomeration on urban economic development and ecological environment from the three perspectives of industrial agglomeration,population agglomeration and sicy spatial spillover.Then,from the three perspectives,empirical research is taken on the relationship between agglomeration and urban ecological efficiency.This paper uses the Super Slack-based Measure(SBM)to measure the urban eco-efficiency of 280 prefecture-level cities between 2003 and 2013,and describes the spatial changes from three aspects:general characteristics,regional characteristics and scale characteristics.The results are as follows:Generally speaking,the eco-efficiency of the prefecture-level cities in China is relatively low,and there is still a lot of room for improvement.From the time series characteristics,the eco-efficiency of the prefecture-level cities in China is generally declining and then rising,and the overall is improved.The difference of ecological efficiency between China's urban environment has narrowed,and the main contribution of the difference is internal.Eco-efficiency does not show the "club" convergence,and the differences that the central regional differences contribute to the overall is increasing.From the perspective of industrial agglomeration,the paper analyzes the influence of industrial agglomeration on urban eco-efficiency based on the improved two-sector production model,and uses the panel data of prefecture-level cities in 2004 and 2013 to measure the industrial agglomeration degree and industrial specialization level of 280 prefecture-level cities.The nonlinear relationship between industrial agglomeration and urban ecological efficiency under different urban scale was analyzed by panel data regression model,and the results were compared according to the results of city scale.The conclusion is that industrial agglomeration and industrial specialization have a significant effect on urban eco-efficiency,and this promotion is greater between western and small cities.The theory of industrial agglomeration and urban eco-efficiency is theoretically U-type relationship,but not significant in the central and western regions and medium-sized cities.The level of industrial specialization has a positive impact on urban eco-efficiency,but it is not significant in the eastern and large cities.Based on the panel threshold model,the threshold effect of different population size and different population density on urban eco-efficiency was discussed by using the panel data of prefecture-level cities from 2004 to 2013.The results show that there is a significant double threshold between the urban population size and the eco-efficiency from the national level.There are also significant double thresholds between the urban population size and the eco-efficiency in the eastern and western regions.From the perspective of population and urban eco-efficiency,there are significant differences in the double thresholds in the eastern,central and western regions.There is a significant relationship between population density and eco-efficiency under different population.Population density and eco-efficiency under different population show a significant heterogeneity of the threshold effect.From the perspective of spatial correlation and spatial spillovers of urban eco-efficiency,the spatial autocorrelation model and the spatial regression model based on STIRPAT model are used to analyze the spatial pattern and spillover effect of urban eco-efficiency in 2003 to 2013.The results show a positive spatial correlation in the urban agglomeration from the spatial dimension,and the aggregation of H-L clusters increases with time.From angle of spatial spillover effect,the eco-efficiency of each unit is not only related to the industrial structure,the level of social and economic development of the region,but also the eco-efficiency of the surrounding neighborhood unit.The growth of government behavior and personal wealth is beneficial to urban eco-efficiency.The efficiency of urban fixed assets investment will significantly reduce the urban eco-efficiency.Foreign direct investment and industrial structure fails to significantly enhance the eco-efficiency,but the spatial lag of industrial structure significantly reduces the eco-efficiency of other cities.Finally,the main conclusions of this paper are summarized,the shortcomings of agglomeration and urban ecological efficiency research are put forward,and the future research direction is prospected.