| Since the 21st century,with the continuous acceleration of urbanization,the ecological environment has been disturbed by natural and human factors,and the regional ecological stability has been seriously affected,which has become an important issue restricting social sustainable development.It is particularly important to develop and utilize natural resources reasonably and improve the quality of the ecological environment at the same time.Through the research on the trade-off relationship between urbanization and ecological risk,the comparative analysis of the level of urbanization and the ecological risk is of great significance for promoting the coordinated and sustainable development of society and the construction of ecological civilization.Taking Henan Province as the research area,based on the concept and theory of urbanization construction and ecological risk,collects the statistical yearbook data and land use data of each city in Henan Province in 2000,2010 and 2018,and uses the index identification method to select population,economic,social and spatial cities and towns.There are a total of 28 indicators of urbanization,and the weight of the indicators is determined by the entropy method,and the comprehensive evaluation index of the urbanization level of each city in Henan Province is obtained.Getis-OrdGi*hotspot analysis is used to explore urban development hotspots and analyze the temporal and spatial variation characteristics of urbanization level.At the same time,using the ecological risk assessment model,land use transfer matrix,kernel density analysis and spatial autocorrelation analysis methods,the temporal and spatial variation characteristics of ecological risk corresponding to land use type transfer in Henan Province were explored.On this basis,the coupling coordination degree model is used to study the trade-off relationship between urbanization level and ecological risk from the two dimensions of time and space,and the following conclusions are drawn:(1)The urbanization of Henan Province is developing steadily,and the high-level regional advantages are prominent.Zhengzhou,Luoyang,and Nanyang have always maintained their rankings in the forefront of the province.Especially Zhengzhou,whose urbanization level score has always been greater than 0.85,has an absolute advantage.Zhumadian City and Xuchang City have seen a significant increase,ranking fourth and fifth respectively in their urbanization scores by 2018.The urban development hotspots in Henan Province are concentrated in the central urban agglomeration with Zhengzhou City as the center,and the urban development is relatively fast.The scores of urbanization subsystems in different cities show different trends.Although the orientation of urbanization in different periods is different,they all change before the orientation of economic urbanization and social urbanization.It is social security and economic development-oriented,and it is an important driving force for urbanization.(2)From 2000 to 2018,the types of land use in Henan Province changed significantly.The area of cultivated land continued to decrease,and it was continuously converted to other land use types.Among them,74.17%were converted into construction land,and the area of construction land continued to increase.It reached 21,614.070km2 in 2018.Mutual transformation,the overall change is not large.The results of Kernel Density analysis show that the urban development in Henan Province is very unbalanced.The construction land in Zhengzhou,Luoyang,and some cities in the central and eastern regions expands rapidly,while the expansion of construction land in the low mountain and hilly areas in the west is not obvious.The spatial distribution of ecological risk areas is relatively concentrated,with each main urban area as the center,and it continues to spread around.The cultivated land and natural environment around the city are affected,which makes the area of high ecological risk level continue to increase,from 13.7%in 2000 to 15.97%in 2018.The risk area has been transformed,and the risk level has continued to rise.The ecological risk level of each city shows the form of low in the west and high in the east.The high-level risk area continues to extend westward,and the risk area changes from a discrete state to a mass aggregation,showing a phenomenon that seems to be caused by economic traction.The Global Moran’s I is 0.519,0.425,0.412,showing a significant positive correlatio.Local autocorrelation shows that the high-high aggregation area is located in the east,while the low-low aggregation area is located in the west,showing a regional aggregation effect.(3)The coupling degree of the 18 cities in Henan Province is in the high coupling stage,while the coupling coordination level is relatively low,most of them are at the barely coordinated level,accounting for about 72.22%,and a small number of cities are on the verge of imbalance,and the overall performance is central>southeast>north spatial distribution pattern.The urbanization level and ecological risk level of various cities in Henan Province are uneven.Among them,Pingdingshan City and Nanyang City maintain a high level of development while maintaining a relatively good ecological environment;Puyang City and Kaifeng City have always been at a medium-low development level and high-level ecological risk.Zhengzhou and Luoyang have relatively high levels of urbanization,but their ecological risk levels are also at the forefront.While the city is developing rapidly,it is necessary to pay attention to the protection of the ecological environment,rational development and utilization,maintain a high level of urbanization,and reduce ecological risks. |
