Research On The Ecological Space Control In The Yangtze River Delta Based On The Relationship Between Supply And Demand Of Ecosystem Services

The rapid development of regional economic society and the continuous advancement of urbanization have led to the occupation of a large number of land with important ecological functions or fragile ecological environments,regional ecological security is seriously threatened,and regional land resources are limited,ecological land is impossible to increase significantly because of economic development’s need.How to conduct ecological space control in a targeted and scientific manner is the current research hotspot.Ecosystem services are closely related to human well-being,which can be reflected in the relationship between the supply and demand of ecosystem services.The Yangtze River Delta(YRD)is one of the most economically dynamic and densely populated areas in China,the relationship between supply and demand is becoming increasingly tense,and its spatial heterogeneity is obvious,misalignment and mismatch between supply and demand space is prominent.Therefore,the study on the ecological space control based on the relationship between the supply and demand of ecosystem services in the YRD has great practical significance for optimizing the pattern of land development and promoting the construction of regional ecological civilization.This paper builds the supply,demand spatial quantitative model of water supply,carbon sequestration,recreation,and integrated ecosystem services,and studies the evolutionary characteristics of the supply-demand relationship of various ecosystem services in the YRD region from 2000 to 2015.The paper delineates the ecological zoning based on the supply-demand relationship of integrated ecosystem services in 2015,and corresponds control strategies are proposed.The conclusions reached are as follows:(1)In the past 15 years,the supply of water supply services in the YRD increased by 2.43%,and the demand increased by 40.22%.The supply-demand relationship has become tense,and the main reason is the increase in demand,especially the increase in industrial water demand.The supply-demand relationship has strong spatial heterogeneity,and it has obvious spatial characteristics of high-high agglomeration and low-low agglomeration.The YRD region should focus on water supply issues in deficit areas,establish and improve ecological compensation mechanisms,and implement deficit water transfer from surrounding surplus areas.(2)under not considering the target of carbon emission reduction,the supply and demand relationship of carbon holding services in the YRD a region tended to be tight during the 15-year period,especially in the central and eastern regions and the supply-demand ratio has dropped from 50.86%to 16.36%;Under the target of 30%emission reduction,the carbon supply-demand ratio in 2015 was 130.44%,and the supply-demand relationship was generally good.The deficit area was mainly distributed in urban centers;Under the target of 60%emission reduction,the carbon supply-demand ratio in 2015 was 43.87%,and the supply-demand relationship was seriously unbalanced.The deficit area was mainly distributed in the middle and east.The widened gap between the supply and demand was mainly due to the increase in CO2 emissions,especially the increase in industrial CO2 emissions.Therefore,it is highly recommended that in order to alleviate the contradiction between supply and demand of carbon sequestration services,in addition to increasing the carbon sink space,we should focus on accelerating the industrial transformation of the supply and demand deficit zone.At the same time,we should also establish a regional compensation mechanism and policy based on carbon sequestration services on the provincial and inter-provincial levels to serve the YRD a integration development goals.(3)The supply of recreation services is far greater than the demand,and the supply and demand relationship is generally good,but the high supply area and the high demand area are obviously dislocated spatially.As the reachable radius expanded from 0km to 50km,the supply-demand relationship within the region has gradually improved,and the area of the deficit area and the unmet population have continued to decrease.According to the evolution law of the relationship between supply and demand under different reachable radius of 41 prefecture-level cities,divide them into 5 types of districts.On the large regional scale of the YRD region,it is necessary to protect concentrated and high supply areas(large mountain forests,water bodies,etc.);Within urban development zones,near-to-medium distance satisfying cities should focus on optimizing the decentralized allocation of green spaces in urban areas based on the supply-demand relationship under different reachable radius;Long-range satisfied or unsatisfactory cities should also increase the allocation of green space in large areas;The ecological space around the boundaries of urban development has become a key area to alleviate the contradiction between supply and demand of urban residents’ leisure and recreation services,especially for long-distance and unsatisfactory cities that must strengthen protection.(4)The supply and demand relationship of integrated ecosystem services is generally good in YRD,but it’s spatial heterogeneity is obvious,and the relationship tends to be tight,the area and population of the supply and demand deficit area has increased significantly.Socio-economic factors,especially the expansion of construction land,have a significant negative impact on the regional supply-demand relationship,and the impact of population growth on the supply-demand relationship of ecosystem services has exceeded the impact of economic growth.This paper divides the YRD into five types of regions:highly surplus regions,general surplus regions,balance regions,general deficit regions,and severe deficit regions based on the comprehensive ecosystem supply and demand index,and the YDR region is dominated by balanced areas,accounting for more than 1/4.