| Urbanization exchanges economic values directly or indirectly with loss and gain changes in ecosystem service functions,and the study of the relationship between the intersection of the two changes is currently one of the hot issues in international interdisciplinary fields such as ecology and economics.In the context of spatial,demographic,economic and social multidimensional urbanization,elucidating the coupling-coordination relationship of various elements in the urbanization process and determining the impact of human activities on related elements can help optimize future land planning schemes and maintain the value of ecosystem services,which is crucial for the sustainable development of regional urbanization and policy formulation.China is currently facing economic transformation,and the contradiction between ecological environment and socio-economic development in the urbanization process is increasingly prominent.Due to the constraints of economic development level and social civilization level,research on the value of ecosystem services in urban agglomerations has been neglected,with the following problems:the assessment of urban ecosystem service values is at a static stage,ignoring people’s different willingness to pay for ecological values in different historical periods and at different ecological supply levels;assessment models generally do not consider the value of land services after completion;the There is little research on the intrinsic link between multidimensional elements of urbanization and changes in ecosystem service values,especially in the case of high human interference.In order to serve the national strategies of "Guanzhong-Tianshui Economic Zone","Belt and Road" and "National Central City",this study draws on the international and domestic research results.Using remote sensing images and land use data,the study elucidates the spatial and temporal variation characteristics of urban land ecosystems in Guanzhong region;estimates the dynamic value of ecosystem services in Guanzhong region using an optimized ecosystem service assessment model,and studies the spatial and temporal variation of urban ecosystem service values in Guanzhong region;analyzes the coupling relationship between ecosystem service values and the comprehensive level of urbanization,and identifies the key factors of human activities.The key factors of human activities were identified;the future ecosystem service values of Guanzhong region under multidimensional urbanization scenarios were predicted by combining CA-Markov prediction model and population growth model.The main conclusions are as follows.(1)The evolutionary characteristics of the land ecosystem in Guanzhong region in the last 30 years in the context of urbanization were elucidated.In the current land use situation of Guanzhong region,the area of construction land expanded 1.68 times compared with 1990,becoming the fastest growing land use type,while the area of arable land in Weinan City remained the largest and the area of forest land in Baoji City remained the largest.The land transfer type is mainly arable land,which shrinks in all cities as urbanization accelerates in the Guanzhong region.The comprehensive utilization intensity index of ecological land increased from 253.63%in 1990 to 255.86%in 2020,indicating that the human land use is over-extended from crude to intensive,and the land use efficiency of human activities increases accordingly.In the past 30 years,the landscape pattern showed a trend of "two increases and one decrease".Among them,the overall increase of landscape fragmentation indicates that the fragmentation of the landscape by human activities in the process of urbanization has gradually increased;the fluctuation of Shannon diversity index has increased,indicating that the control and influence of a single type of landscape on the Guanzhong area has weakened,the complexity of the landscape has increased,and the way of human modification of land use types has developed in a diversified manner;the degree of landscape connectivity has gradually decreased,indicating that the extension and clustering between various types of patches of the landscape have decreased.The degree of landscape connectivity gradually decreases,indicating that the extension and aggregation between various patches of the landscape decreases,which also supports the increase of landscape fragmentation.(2)Considering the service types,land use types,administrative divisions,spatial aggregation and the supply capacity of hot and cold spots,the spatial and temporal variation patterns of ecosystem service values in Guanzhong region were revealed.In time,the change of total ecosystem service value throughout the study years showed a trend of decrease-fluctuating increase-and then slow decrease,with a minimum value of RMB 44,822.32×106 in 1995 and RMB 56899.41 ×106 in 2020.The total value of ecosystem services in all five cities in the Guanzhong region has changed.The total value of ecosystem services in Xi’an decreased by 1131.79×106 Yuan,while the total value of ecosystem services in Baoji increased most significantly.This further indicates that the land use changes brought about by regional urbanization have a direct impact on the ecosystem services value and it deserves sufficient consideration in future urban planning and development construction.Spatially,the total and per capita ecosystem service values in the Guanzhong region maintain a "center-periphery","low inside-high outside","low in the east-high in the west",and "low in the west-high in the west"."and "low in the east-high in the west".In terms of service types,the four service types show"two increases and two decreases",i.e.,the proportion of cultural and regulating services increases,while the proportion of supporting and provisioning services decreases;regulating services always dominate the total service value.Over the 30-year period,all land use types experienced different degrees of change,with forest and grassland experiencing significant increases in ecosystem service values,and built and unused land experiencing significant decreases.The great difference in ecosystem service yield by land use type indicates that the substrate has a great influence on the value of ecosystem services.1990-2020,the districts and counties with high ecosystem service yield are concentrated in the western part of Guanzhong region,and those with low yield are mostly distributed in the central part of Guanzhong region.The strong hot spot service areas are concentrated in the southwestern part of Guanzhong region,while the very strong cold spot service areas appear in the central part of Guanzhong region and are concentrated in a row.(3)The coupling relationship between urbanization and ecosystem service value in Guanzhong region was established,and the most significant factors of human activities on the coupling and coordination relationship were identified.The comprehensive urbanization level index of each district(county)in the Guanzhong region shows spatial variability characteristics of center-periphery,low in the north and high in the south;with Xi’an city as the core and Xianyang city as the second core,there is an obvious hierarchy.The results of the interaction between urbanization and ecosystem service value show that:the comprehensive level of urbanization in Xi’an is higher than the ecosystem service value;the comprehensive level of urbanization in Xianyang and Tongchuan is equal to the ecosystem service value,and the ecosystem and urbanization process of the cities are relatively balanced;Baoji and Weinan are lagging behind in urbanization,and the comprehensive level of urbanization is lower than the ecosystem service value.The coupling-coordination relationship between the value of ecosystem services and the integrated level of urbanization generally shows the spatial characteristics of high in the south and low in the north.Major cities in the south are in a balanced development stage,while cities in the north are in an unbalanced development stage,while cities in the center are in a transitional development stage.Specifically,7 cities in the south are in the balanced development stage,15 cities in the center are in the transitional development stage,and 32 cities in the north are in the unbalanced development stage.By using ordinary least squares(OLS)regression and ordered probability model(ordered Probit model),the two factors of "tertiary employment" and "urban disposable income" are the key factors influencing the coordination between the value of ecosystem services and urbanization in Guanzhong County.(4)The future land use pattern under the composite scenario was simulated,and the development trend of ecosystem service value under the multidimensional urbanization scenario was predicted.The IDRISI 17.0 Selva software was used to simulate the future land use profile of Guanzhong region,and after passing the accuracy test with a Kappa index of 0.905,it was concluded that the construction land in Guanzhong region increased significantly in 2025,reaching 58,332.98 hm2,and the forest land area increased by 4,250.3 hm2,while other land uses had each decreased differently,with grassland decreasing the most.With the rapid economic rise and unprecedented urbanization in Guanzhong region,the dynamic changes of land use are remarkable.Non-construction land has been transferred to construction land in large quantities,which means that the land use change situation in Guanzhong region is obviously influenced by human disturbance.According to the results of the logistic Stix growth model projections,the total resident population in the Guanzhong region is obtained to continue to grow in 2025.Compared to 2020,the remaining cities show a decrease in population due to population outflow,while Xi’an,Baoji and Weinan show growth,especially Xi’an,which shows the largest increase.The forecast results also coincide with the 14th Five-Year Plan for National Economic and Social Development and the 2035 Vision Plan of Shaanxi Province.The total value of ecosystem services in Guanzhong region will reach 57,040.99×106 Yuan in 2025,which is only an increase of 141.58×106 Yuan compared to 2020.The accelerated expansion of construction land with little increase in ecosystem service value highlights the importance of conserving ecological land to maintain ecosystem service values.In terms of specific ecosystem service value types,soil conservation remains the dominant service value contributor(9087.97×106 Yuan).At the level of individual administrative municipal units,the total value of ecosystem services in 2025 shows significant spatial inequality(Xi’an has a significantly lower total value of ecosystem services than neighboring counties and cities.The per capita ecosystem service values in Guanzhong region in 2025 maintain the spatial heterogeneity of "high in the west-low in the east" and "high in the outside-low in the inside"."The spatial heterogeneity of Guanzhong region in 2025 was maintained.Xi’an,as the administrative,economic and political center of the study area,has a strong urban absorption capacity,but remains a spatial depression in ecosystem service values.The highest-level area remains around Baoji City,i.e.,Taibai County. |
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