| Urbanization has been proved to be an inevitable trend of human development.Since it came into the twenty-first century,China is experiencing unprecedented urbanization speed and scale,Socioeconomic level and residents’ life have risen immeasurably.However,rapid urban development has also led to resource consumption,pollutant emission,eco-environment deterioration and other problems.How to improve the eco-environmental quality while ensuring the high-quality development of urbanization has become a hot issue in the scientific research.As an important ecological security barrier in northern China,the Yellow River Basin is rich in natural resources and plays an important role in the ecological security and economic development pattern.However,the fragile eco-environment and relatively backward industrial structure of the Yellow River Basin hinder the economic development of the basin.In 2021,China officially defined "Ecological Protection and High-quality Development of the Yellow River Basin" as the major national strategy.The study of typical regions in the Yellow River Basin can not only reveal the interaction between urbanization and eco-environment in the Yellow River Basin,but also contribute to the formulation of relevant policies for urbanization construction and eco-environmental protection,which is of great significance to the social and economic development and eco-environmental protection of the Yellow River Basin.Therefore,this study selects the typical regions of the Yellow River Basin as the research objects and establishes an urbanization and eco-environment index evaluation system according to the actual situation of the region.On this basis,the modeling analysis,machine learning algorithm and spatial geographic information analysis technologies are comprehensively used to analyze evolution trend and interaction mechanism of regions with different development levels and eco-environmental quality between urbanization and eco-environment in the Yellow River Basin from three spatial scales of counties,urban agglomerations and the whole basin.The main conclusions of the study are as follows:(1)Based on the grey correlation degree(GRA)model,the specific factors influencing the interaction between urbanization and eco-environment in the relatively backward areas of the Yellow River Basin were identified.For the temporal perspective,the coupling coordination relationship of urbanization and eco-environment in Ningxia has been transformed from an uncoordinated state to a coordinated state from 2001 to 2018(CCD>0.5).The comprehensive level of urbanization shows an increasing trend,and the comprehensive level of eco-environment shows a fluctuating upward trend under the influence of environmental pressure.For the spatial perspective,the coupling coordination degree between urbanization and eco-environment in Ningxia is in the transition stage from imbalanced to coordination,which shows obvious spatial correlation.The industrial counties in the north regions have a higher urbanization level,while the mountainous areas in the south have a better ecoenvironment.The results of specific indicators analysis show that population factors have a great impact on the eco-environment in backward regions,and urban greening and water resources are the main limiting environmental factors on urban development.(2)Based on the random forest and geographically and temporally weighted regression model(GTWR),the importance changes and spatiotemporal differences of the influencing factors of urbanization in Shandong Peninsula Urban Agglomeration(SPUA)in the Yellow River Basin were clarified.From 2001 to 2020,the comprehensive index of high-quality urbanization continued to rise,with a large gap between eastern and western cities.The comprehensive index of eco-environmental quality continued to rise,especially in eastern developed cities.The coupling coordination degree between high-quality urbanization and ecoenvironmental quality in SPUA has increased significantly,and the coupling coordination degree in developed regions is far higher than that in relatively backward regions.In addition,the coupling coordination degree of SPUA shows a ’high-high’ clustering in the east and a ’lowlow’ clustering in the west.For specific indicators,the importance of economic indicators decreased,the importance of demographic and spatial indicators increased and the energy consumption per capita is the main indicator affecting the eco-environmental quality.Compared with eastern cities,the impact of urbanization indicators on eco-environmental quality shows significant spatio-temporal heterogeneity,and the spatial factors have a stronger impact on the eco-environment quality in the western cities.The high-quality urbanization indicators have improved the eco-environmental quality of the eastern coastal cities,but have no similar effect on the western backward cities.This indicates that the eastern coastal cities have reached the stage of coupling development between urbanization and eco-environmental quality,while the western backward cities still have much gap for improvement.(3)Based on multi-source remote sensing data,the impacts of urbanization and ecoenvironmental quality on coupling coordination degree at the scale of the Yellow River Basin were revealed.From 2001 to 2019,the overall urbanization level,eco-environmental quality and coupling coordination degree of the Yellow River Basin showed varying upward trends,among which the urbanization level and coupling coordination degree show a relatively significant increase,while the change of eco-environmental quality is not obvious.The change rate of the coupling coordination degree and urbanization level in the eastern regions is significantly higher than that in the western regions.At the city scale,the change trend of urbanization and coupling coordination degree is similar,which are significantly higher along the middle and lower reaches of the Yellow River Basin than that along the upper reaches of the Yellow River Basin.At the county scale,the coupling coordination degree shows a significant spatial correlation,and the whole basin presents a ’low-low’ clustering phenomenon.At present,the coupling coordination degree of the Yellow River Basin is mainly affected by the urbanization level.With the continuous advancement of high-quality development of the Yellow River Basin,attention should be paid to the impact of urban development on the ecoenvironment in the future,to ensure the parallel improvement of high-quality urbanization and eco-environment quality,and to promote the sustainable development of the Yellow River Basin.In conclusion,this study firstly improved the coupling coordination degree(CCD)model to make it applicable to spatiotemporal analysis.At the same time,combined with factor correlation analysis and gray correlation analysis,it was determined that population,urban greening and water resources were key factors affecting urbanization and eco-environment in relatively backward regions of the Yellow River Basin.Secondly,the random forest model in machine learning algorithm was introduced into the assessment of eco-environment quality influencing factors for the first time,and the model comparison revealed that the geographically and temporally weighted regression(GTWR)model was better than other models in determining the spatiotemporal impact mechanism of indicators.Combined with Moran’s index analysis,it was revealed that energy consumption was the most directly influencing factor on eco-environmental quality in developed regions of the Yellow River Basin,while the impact of economic factors is gradually weakening.Therefore,the western regions should accelerate the transformation of production structure to meet the demands of high-quality development.Finally,combined with multi-source remote sensing technology,it was confirmed that the urbanization of the Yellow River Basin at this stage played a decisive role in the coupling coordination system.This study provides an important scientific basis for the formulation and implementation of policies for high-quality development and eco-environmental protection in the Yellow River Basin by revealing the trends of interaction between urbanization and ecoenvironment at different scales and the spatiotemporal changes of influencing factors in the Yellow River Basin. |
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