Research On Urban Green Space Ecosystem Service Evaluation Based On Supply And Demand Balance In Taiyuan

With the rapid developments of urbanization levels in various cities,the balance and sustainable development of ecosystems had been seriously affected.Urban green space is a very significant part of urban ecosystems.They play a positive role in urban environment,they can improve citizens' living and environmental quality,provide social benefits,and maintain ecosystem's balance and stability.How to optimize the urban green space structure and maximize the ecosystem service function has become key issues facing urban sustainable development and urban ecological civilization construction.This study constructs the urban green space ecosystem service function and demand evaluation system of Taiyuan,and comprehensively evaluated the balance of supply and demand of ecosystem services with reference to the relevant indicators of eco-city construction,in order to provide decision-making basis for the future urban green space green space construction and planning design in Taiyuan and maintain the developments of ecological civilization construction continuously.The main results obtained by this research were as follows:1 This study divided the urban green space of Taiyuan into six categories: park green space,residential green space,other auxiliary green space,road green space,protective green space and regional green space,their green land occupation ratio of each green land type respectively were 70.4%,31.2.%,35.7%,98.6%,98.6%,96.0%.2 This study established an ecosystem service function evaluation system including regulatory services,support services,cultural services and 9 specific evaluation indicators,as water conservation,carbon sequestration,air purification,dust mitigation,noise reduction,microclimate regulation,soil conservation,biodiversity conservation and social services.3 After analyzing the evaluation results of urban green space ecosystem service function value in Taiyuan from 2005 to 2017,the following conclusions were drawn:1)In the past 12 years,although the total value of urban green space ecosystem services in Taiyuan had increased from 1.67 billion yuan / a to 3.595 billion yuan / a,the total value of per capita ecosystem services had increased from 487.09 yuan / a to 820.83 yuan / a,but the growth rate of the total value of ecosystem services had not kept pace with the growth of GDP.2)According to the composition analysis of the total value of urban green space ecosystem servicesin Taiyuan at 2017,following various composition's sequences were obtained:regulating services>support services>cultural services;adjusting microclimate>reducing noise>carbon fixation and oxygen release>conservation water source>soil Maintain>biodiversity conservation>social services>clean air>dust Relief;regional green land>other subsidiaries>living green land>road green land>protective green land>park green land;Jinyuan District>Xiaodian District>Tiancao District>Wanlin District> Yingze District> Xinghualing District.3)In Taiyuan,the total investments in urban green space in 2017 was 876 million yuan/a,and the input-output ratio of urban green space construction was about 1: 4.4 This study established an ecosystem service demand evaluation system corresponding to the ecosystem service function evaluation system.Among them,there was progressive room for Taiyuan's environmental comfort index,urban air quality,PM2.5 compliance rate,soil and water conservation rate and the 10,000-person comprehensive park index.5 There was still a certain gap between urban green space ecosystem service functions and needs in Taiyuan.Taiyuan should continue to strengthen urban green space construction and optimization,and improve each unit area's ecosystem service function of urban green space.