Research On The Spatial-temporal Differences Of The Ecological Carrying Capacity Of Urban Agglomeration In The Middle Reach Of Yangtze River

Development is always the theme of this era.City is the main gathering place of population,how to promote its healthy and high quality development has always been the main topic for scholars,all over the world,to explore.Urban agglomeration in the middle reach of Yangtze river is composed of three major city in Central China(e.g.Wuhan city circle,the Ring of Chang-Zhu-Tan Urban Agglomeration.The Poyang Lake urban agglomeration),covering 31 prefecture level city(provincial city).Its area of jurisdiction is ranking the forefront in our country,which is known as the new "growth pole" of China.Therefore,to carry out the ecological carrying capacity of the urban agglomeration in the middle reach of Yangtze river,it is useful for exploring the development and coordination of resources,environment,society,economy and other factors in the past 15 years.It is of great significance to play a better role in the future and provide scientific and reasonable suggestions or countermeasures for the sustainable development of the region.In this paper,the 31 cities of urban agglomeration in the middle reaches of the Yangtze River are the research target.2005,2010 and 2015 these three times nodes are selected.Principal component analysis method is used to determine the evaluation index.And the corresponding index system is constructed.The index weight is determined by entropy method,and a comprehensive rating model is established.The spatial-temporal differences of the ecological carrying capacity is researched from three levels:ecological elastic capacity,ecological support capacity and the ecological pressure.According to those,we calculated the ecological carrying capacity index of the 31 cities in the years of 2005,2010 and 2015 respectively.The main conclusions in this paper include:(1)The study of urban ecological carrying capacity is not a single index calculation,but a comprehensive consideration of a variety of factors(e.g.resources supply and consumption,population pressure,economic growth,environmental pollution,social progress).These factors jointly restrict the level of ecological carrying capacity in the study area.(2)The average ecological carrying capacity of urban agglomeration in the middle reach of Yangtze river in the years of 2005,2010,2015 are maintained at medium level,showing a rising trend,which in 2015 than in 2005 has rose 28%.In the past 15 years,it showed that the urban agglomeration in the middle reach of Yangtze river has improved the ability of how to prevent and control the environmental pollution,with the continuous improvement of the economic level and social progress.With the promotion of a variety of factors,its situation of ecological carrying capacity has been improved.(3)The inner difference of the ecological carrying capacity in the urban agglomeration in middle reach of the Yangtze River is obvious.In the three years,the ecological carrying capacity index of the Poyang Lake urban agglomeration is the highest,the Ring of Chang-Zhu-Tan Urban Agglomeration is the second and the Wuhan city circle is the lowest.Because the geographical position of Poyang Lake urban agglomeration is in the southeast,it is close to the southeast coast of the summer mind.And its climate resources,forest resources and water resources is more abundant,the elastic force index of the ecosystem is higher,and the stability is stronger.Besides,compared to the Wuhan city circle,the economic level of Poyang Lake urban agglomeration is a bit low,and the ecological pressure is weak,but its ability of the ecological supporting capacity is better than Wuhan city circle.In general,the Poyang Lake urban agglomeration is slightly better than the Wuhan city circle in the ecological carrying capacity because of a variety of factors,and there are spatial differences between these regions.