Study On The Spatio-temporal Impacts Of Urbanization On The Ecosystem Services Value And Ecological Sustainability Assessment

In recent years,more and more studies have found that rapid urbanization has a significant impact on regional Ecosystem Services Value(ESV).In order to realize the coordinated development between the urbanization and the ecological system,the key is how to quantify the value of ecosystem services accurately,and clarify the impact of urbanization on regional ecosystem services.Currently,the evaluation of ESV is mainly based on the equivalent factor table of Costanza et al.and Xie et al..However,such equivalent factors are the mean of ecosystem services function at global or national level,which can not reflect the spatial heterogeneity of ESV.In order to solve the problems mentioned above,this study selected five eco-geographic indicators(including NPP,rainfall,habitat quality,soil erosion and transportation convenience)to modify eleven functions of terrestrial ecosystem in China.Subsequently,ESV at city-level was assessed based on our spatial heterogeneous equivalents.Then,through the review of existing literature,this study selected three key urbanization indicators(including population urbanization,land urbanization and economic urbanization),and examine the spatial agglomeration characteristics of urbanization and ESV.On the basis of above work,Geographical Weighted Regression(GWR)was applied to model the spatiotemporal ecological impacts of urbanization.Through the analysis of the underlying mechanism behind the spatiot-emporal differentiation impacts,spatial panel model was further used to empirically study the non-linear effect of urban expansion on ESV.Finally,in view of the significant impact of urbanization process on regional ESV,Super-efficient SBM model was used to incorporate regional ESV into eco-efficiency assessment,thus providing a more comprehensive reference for regional sustainable development.This study found that China's construction land experienced a large-scale growth between 2000 and 2015.Except for waterbody,the remaining land types experienced different degrees of decline.Based on the built spatial heterogeneous equivalent factor table,China's total ESV in 2015 was 29.12 trillion yuan,of which forest ecosystem contributed the most.In addition,from the perspective of spatial distribution,ESV per unit area is gradually reduced from southeast to northwest.In terms of temporal changes,there was a trend of increasing first and then decreasing during 15 years.In the end,ESV increased by 742 million yuan.Through the global and local autocorrelation test,this study found that different urbanization factors and ESV had significant spatial agglomeration characteristics.Further,by adopting Geographical Weighted Model,this study explored the spatio-temporal impacts of urbanization and geographic factors.The specific performance was as follows: Firstly,the altitude had a negative impact overall;Secondly,the impact of urban development intensity was the most dramatic,with a negative impact on the whole,but the intensity of the impact was weakened year by year;Thirdly,human activities also had a negative impact overall,but the spatial distribution of impacts had not changed significantly;Finally,unlike the former two urbanization factors,economic activity had a positive impact.The spatial econometric model was used to further empirically study the spatial spillover effects of urbanization factors.The study showed that the expansion of urban construction land had a non-linear impact on tESV.With the growth of urban scale,the ecological impact of urban expansion presents an “M” curve.In addition,the primary industry had a positive impact,and the other two industries had no significant impacts.Finally,human activities had a negative impact on ESV.Finally,after incorporating regional ESV into the eco-efficiency assessment framework,this study found that ESV had a significant impact on regional eco-efficiency.The specific performance is that the eco-efficiency level in the eastern coastal areas decline,and the slack improvement of ESV is much higher than other factors.It can be seen that ESV is of great significance in ecological sustainability assessment.