Study On Ecosystem Service Flow In Guangdong-Hong Kong-Macao Greater Bay Area Based On Supply And Demand

With the development of the Guangdong-Hong Kong-Macao Greater Bay Area strategy,a large number of talents have been attracted to the construction and development.Population aggregation and rapid social and economic development have brought certain pressure to the local ecological environment.Therefore,coupling the supply of ecosystem services and the flow of human needs in space is the key to achieving harmonious coexistence between man and nature.Based on the In VEST model and related socio-economic data,this study evaluates the supply and demand of ecosystem services in the Guangdong-Hong Kong-Macao Greater Bay Area.The corridors obtained by river,wind direction and circuit theory are used as the path of ecosystem service flow to connect the supply and demand areas,so as to obtain the flow changes and important ecological nodes of water production service flow,habitat quality service flow,carbon fixation service flow and comprehensive ecosystem service flow in the Guangdong-Hong Kong-Macao Greater Bay Area,in order to provide reference for ecological restoration.The main results are as follows:(1)In terms of the supply and demand relationship of ecosystem services,the supply and demand relationship in the Guangdong-Hong Kong-Macao Greater Bay Area continues to be tense.In the past two decades,the supply and demand ratio of the three services has continued to decline.Among them,the total supply of water production services is unstable due to the change of precipitation,the overall fluctuation is large,and the total demand increases first and then decreases.The average supply of habitat quality services continued to decline,and the demand continued to rise.The total supply of carbon sequestration services decreased first and then increased,and the total demand continued to rise.Overall,the relationship between supply and demand of water production,habitat quality and carbon sequestration services in the Guangdong-Hong Kong-Macao Greater Bay Area continues to be tense.(2)In terms of supply and demand clustering of ecosystem services,the area of cold spots(main demand areas)in the Guangdong-Hong Kong-Macao Greater Bay Area continued to expand.In the past two decades,the cold spot area(main demand area)of the three ecosystem services has expanded to varying degrees.Among them,the cold spot area of water production service expanded by 276.10 km~2,the cold spot area of habitat quality service expanded by 2171.47 km~2,the cold spot area of carbon sequestration service expanded by 1341.57 km~2,and the cold spot area of integrated ecosystem service expanded by 1001.51 km~2.In addition,due to the rapid urban expansion of Dongguan,the cold spot area increased,and the cold spot area of habitat quality service gradually developed from the Guangfo and Gangshen demand areas to the central demand area,reflecting the significant spatial growth of habitat quality service demand in the Greater Bay Area.(3)In terms of ecosystem service flow,the supply and demand deficit has been alleviated,and the ecological obstacle points are concentrated.The water production service in the Guangdong-Hong Kong-Macao Greater Bay Area flows dynamically through the river,and the supply and demand deficit of the service is alleviated to a certain extent by the supply of the western supply area in the Guangfo demand area.The supply and demand deficit in the port and Shenzhen demand area is difficult to alleviate due to the lack of major rivers connected to the main supply area for its water supply.The carbon sequestration service takes the wind direction as the path to make the carbon sequestration service transfer carbon sequestration in space.Among them,the Guangfo demand area is transmitted by wind direction,which can transfer part of its supply and demand deficit to the western supply area for carbon sequestration;the supply and demand deficit in the port and Shenzhen demand area is on the rise,and it is difficult to transfer the deficit part to the main supply area for carbon sequestration on the wind direction movement path.The number of supply and demand corridors of habitat quality services increased first and then decreased.The high value of corridor current density is mainly distributed in the east and west sides of the main demand area(Foshan,Dongguan,Huizhou).The pinch points are concentrated in Foshan,Dongguan and Huizhou.The obstacle points are concentrated in Guangzhou,Foshan,Dongguan and Zhongshan.(4)In terms of integrated ecosystem service flow,the pattern of integrated ecosystem service flow with’dual-core’demand area and external supply area as ecological barrier is constructed,and the important ecological nodes in the connection path are obtained.Among them,most of the ecological obstacle points are distributed in Dongguan and Zhongshan with large land use change in recent years.In order to maintain the smooth flow of services,ecological restoration of ecological obstacle points in this area is needed.