Comprehensive Assessment Of Ecosystem Services In Urban Agglomerations Of Changzhutan From The Perspective Of Supply And Demand

Ecosystem services refer to the direct or indirect access of human beings from ecosystems to a variety of required services and products,and the bridge between natural ecosystems and socio-economic systems is built by supply and demand.As the main space of China’s new urbanization,urban agglomerations play an active role in promoting regional social and economic development,but in the process of rapid urbanization,the supply of ES gradually declines,while human ecological demand gradually increases,and the imbalance between supply and demand gradually intensifies,which in turn affects the healthy and sustainable development of urban agglomerations.Quantitative assessment of ES and the use of spatial control to achieve a dynamic balance between regional supply and demand are essential to maintain the ecological security of urban agglomerations,while existing studies are mostly based on supply-side assessments and insufficient consideration of human ecological needs.In view of this,this paper takes the perspective of supply and demand as the starting point to explore the current characteristics and space-time evolution of the pattern and the relationship between supply and demand of ES,and formulate reasonable management policies accordingly to meet the dual needs of ecological protection and socioeconomic development of urban agglomerations.This article taking the Urban Agglomeration of Changzhutan as an example,firstly,using InVEST models and digital models to quantitatively evaluate the supply and demand of four regional key ES(water production,carbon sequestration,food supply and soil conservation)in the urban agglomeration,from 2000 to 2018.Secondly,using the correlation analysis of R language to clarify the trade-off and synergy of multiple ES,introducing the supply-demand ratio equation to measure the balance between supply and demand quantity and combining Z-score standardization and quadrant method to analyze the spatial matching relationship between supply and demand.Finally,considering the current characteristics and evolution trend of supply and demand of ES,a comprehensive spatial control framework for urban agglomerations is constructed,and corresponding control strategies are proposed for different control zones.The results show that:(1)On the supply side,the food supply in the Dongting Lake Plain area and the hilly area of central and southern Xiangzhong is high,and the water production,carbon sequestration and soil supply in the Luoxiao-Mufu Mountains,the Hengshan Mountains,the Yumai of the Xuefeng Mountains and the northern branch of the Wuling Mountains are high,and the water supply has decreased by 11.42%in the past 18 years Carbon sequestration increased by 9.52%,food supply increased by 48.37%,and soil retention decreased by 9.52%;(2)On the demand side,the water production,carbon sequestration and food demand in the concentrated construction areas of the middle and lower reaches of Xiang,Zi,Yuan,and Li are concentrated,and the spatial distribution of soil erosion and soil maintenance high value areas is consistent,1 In the past 8 years,the demand for water production has increased by 12.44%,and carbon emissions have increased by 271.35%,which is particularly significant,and the demand for food has decreased by 20.20%,soil erosion has reduced by 10.07%;(3)In terms of the balance of supply and demand,the urban agglomeration shows a pattern of "overall surplus and partial imbalance",and the supply and demand deficit area is mainly concentrated in the urban concentrated built area The core area of Changzhutan is the center and has a tendency to expand outward,and the services of unbalanced supply and demand are water production,carbon solidification and food supply,which is related to the high demand for "water-energy-grain" in the core area of the urban agglomeration,and the ecological compensation mechanism should be improved to ensure the dynamic balance of regional supply and demand;(4).In terms of supply and demand space matching,the spatial misalignment of low supply-high demand with higher risk is less,mainly concentrated in the core built-up areas of urban agglomerations,and the safer high supply-low demand,low supply-low demand are the main matching types.Finally,comprehensively considering the current situation of supply and demand of ES and the risk of supply and demand in the urban agglomeration,the urban agglomeration is divided into different spatial control areas,and the corresponding spatial control requirements and suggestions are proposed,so as to provide a scientific basis for the realization of high-quality development of the urban agglomeration.