Spatiotemporal Evolution Characteristics Of Supply-flow-demand Of Key Ecosystem Services In Shandong Province And Their Optimal Regulatio

Ecosystem services reflect the interrelationship between the ecological environment and human activities in the area.As a important province in eastern China,Shandong Province has had some conflicts between economic development and ecosystem services in the past 20 years.With the reduction of agricultural land and the degradation of forest land and grass land in Shandong Province,biodiversity is reducing and carbon sequestration capacity is weakening.At present,the hot topics in the academic circle are: quantifying the temporal and spatial changes of ecosystem services,analyzing the supply and demand of ecosystem services in the region from multiple perspectives,and putting forward reasonable suggestions for policy formulation by setting up future scenarios.Based on the land use change in Shandong Province in the past 20 years,this study analyzed the spatio-temporal changes of four kinds of key ecosystem services,discussed their supply and demand relationship,analyzed their spatial circulation,discussed the future changes of ecosystem services under different policies,and sought land use optimization scenarios in line with the concept of sustainable development,so as to seek land use optimization scenarios that conform to the concept of sustainable development and achieve a balance between regional economic development and ecological protection.In this study,the supply and demand of four key ecosystem services in Shandong Province,namely,water production service,soil conservation service,carbon sequestration service and biodiversity maintenance service,were quantitatively evaluated by using In VEST model and Arc GIS software.The temporal and spatial distribution characteristics of ecosystem services since the21 st century are analyzed,and the matching relationship and circulation between supply and demand are evaluated.The FLUS model was used to simulate land use change under three different scenarios,and the comprehensive benefits of ecosystem services in the future were discussed accordingly,which provided scientific basis for realizing sustainable development in Shandong Province.The main contents and conclusions are as follows:(1)Analyze the spatiotemporal distribution of supply and demand for ecosystem services.In terms of supply,the supply and demand of key ecosystem services in Shandong Province had strong spatial specificity,the supply of water production services in peninsula and coastal areas was stronger,and the soil conservation services,carbon sequestration services and biodiversity maintenance services in mountainous and hilly areas with extensive forest and grassland distribution were significantly higher than those in plain cultivated areas.The supply of water production services is greatly affected by the inter-annual change of precipitation,carbon sequestration services and biodiversity maintenance services are decreasing year by year,and soil conservation capacity is increasing.In terms of demand,the demand for various ecosystem services is greater in urban centers than in plain cultivated areas.In terms of demand,water production services and carbon sequestration services are more demanding in urban centers,while soil conservation services are less in plain areas.The demand for water production services is declining,and soil conservation services and carbon sequestration services are on the rise.(2)Analyze the spatial and temporal distribution of supply and demand matching of various ecosystem services.In the study area,the supply of ecosystem services generally meets the demand,and there are fewer areas where supply and demand are unbalanced.The areas with unbalanced supply and demand of water production services are mainly distributed in areas with relatively little precipitation such as the Luxi Plain,the imbalance between supply and demand of carbon sequestration services is mainly in urban centers,and the demand for biodiversity maintenance services in Ludong is greater than the supply.(3)In areas where supply and demand do not match,ecosystem services need to flow to other areas,and the flow of water production services and soil conservation is mainly closely related to the flow direction of rivers,and the surplus of water production services is large,and it flows downstream and eventually flows into lakes and oceans.The circulation of carbon sequestration services is mainly related to the wind direction,and the unfixed carbon flows into the nearby area with the wind and is absorbed,and does not flow out of the study area.(4)Under the three scenarios of urban natural expansion,ecological protection redline restriction and arable land protection,the overall trend of four key ecosystem services showed a downward trend.The ecological protection redline scenario has the best overall benefits of the four key ecosystem services in 2050,and in the future development,it is more in line with the scientific concept of sustainable development to adopt strict restrictions on the ecological protection redline.