Urban Sustainability Evaluation Based On Ecosystem Services Value

China's rapid urbanization has greatly promoted the development of social economy in the past 40 years.During this process,the problems of low production efficiency,industrial structure and irrational land use have caused damage and threat to the ecological environment.Besides,the pressure in ecosystem services value(ESV)is increasing due to rapid urbanization,which affects the urban sustainable development.Thus,identifying the impact on urbanization process of the ecosystem services value becomes significantly important of realizing the urban sustainable development.By taking Tianjin Binhai New Area as the research object,this paper used Landsat TM remote sensing image and socio-economic data from 2000 to 2016 to quantitatively analyze the changes of six land use categories in forest,grassland,cropland,water,build-up land and unused land.This paper evaluated the ESV of Binhai New Area according to Xie et al.'s adjusted ecosystem service value equivalent factor table.From 2000 to 2016,the ESV of Binhai New Area decreased from 5.705 billion yuan to 3.356 billion yuan with a decrease of 41.18%due to the significant reduction of water and farmland and the increasing of built-up land.Meanwhile,This paper used the analytic hierarchy process and entropy method to establish a comprehensive evaluation index system for urbanization level.It was found that the urbanization level score of Binhai New Area increased from 0.081 in2000 to 0.915 in 2016 with an average growth rate of 15.14%.also,a negative correlation between urbanization level and ESV through correlation analysis was identified.The negative correlation between economic urbanization and ESV was higher than other urbanization subsystems,which the correlation coefficient was-0.993.Fixed asset investment has a certain role in promoting economic growth,and the difference in GDP added value driven by fixed asset investment per unit area is obvious.This paper defined a novel urbanization indicator named GDP per unit area of fixed asset investment(UAGDP),which indicated that the investment efficiency of the regional economy.According to the relationship between UAGDP and ESV,the degree of coordination between urbanization and ecosystem was evaluated.From 2000 to 2016,the GDP of Binhai New Area increased year by year,but the UAGDP decreased from 1.37×10~-55 hm~-22 in 2000 to 9.56×10~-66 hm~-22 in 2016.The economic investment efficiency decreased first and then increased.The relationship between UAGDP and ESV was phased during the study period.From 2000 to 2012,there was a positive correlation between ESV and UAGDP,and the slope was positive.From 2012 to 2016,ESV was negatively correlated with UAGDP,and the slope was negative.Thus,the degree of coordination between urbanization and ecosystems increased.It was because fixed asset investment as a share of GDP fell by 15 percentage points.The comparison showed that the urban development mode of Binhai Bew Area was not sustainable,and the degree of coordination between urbanization and ecosystem of Shenzhen city was higher than Pudong New Area and Binhai New Area.Therefore,it was an effective way to achieve urban sustainable development that maintaining the value of ecosystem services by protecting ecological infrastructure,improving the level of industrial development and improving the efficiency of economic investment.