Evaluation And Optimization Of Supply And Demand Of Water Ecosystem Services In Xiaoqinghe River Corridor In Jinan City

With the rapid development of the global economy,human production activities pose a great threat to the natural ecosystem.The change of land cover types and the increase of population aggregation lead to the gradual decline of regional ecosystem function.The growing demand for water resources has seriously affected the regional water ecological balance and sustainable development.Urban water problems such as the shortage of water resources,flood disasters and the decline of groundwater level occur frequently,and there are also some phenomena in urban rivers,such as water pollution,encroachment of waterfront space,reduction of biodiversity and so on.The emergence of urban water environment problems is the concrete manifestation of the imbalance between supply and demand of urban water ecosystem services.China is in the critical period of the construction of water ecological civilization and the construction of ecological corridors.This thesis quantitatively evaluates the supply and demand services of urban rivers,analyzes the equilibrium relationship between supply and demand of water ecosystem services,and reveals the reasons for the mismatch of supply and demand services.it is helpful to provide reference for the restoration and management of urban water ecosystem and the landscape construction of river corridor.By clarifying the relevant theoretical and practical basis of the research on the supply and demand of river corridors and water ecosystem services,the scope of literature research is mainly focused on two kinds of regional scales: administrative areas and functional areas.the research on the quantitative evaluation of the needs of urban residents is slightly insufficient,most studies focus on the quantitative evaluation of supply services and regulation services,and lack of a method system that can integrate the supply and demand of all kinds of water ecosystem services.Taking Xiaoqing River in Jinan as an example,this thesis constructs the supply and demand evaluation system of river corridor water ecosystem services,and analyzes the corridor space optimization strategy on the basis of supply and demand equilibrium analysis.Firstly,the study area is determined by combining the ecological benefits under different corridor widths and the current road network in Jinan,and the river corridor water ecosystem service types are identified.According to the Millennium ecosystem Service Classification system,eight types of water ecosystem services are selected for analysis,and the quantitative evaluation methods of supply and demand of each service type under corridor scale(In VEST model,So IVES model,RUSLE model,etc.)are made clear.Combined with relevant research and government documents,the quantitative results of supply and demand of each service type are tested,and the quantity and spatial distribution characteristics of supply and demand of each service type are analyzed.On this basis,ESAI index and cluster analysis are used to evaluate the equilibrium state of water ecosystem service supply and demand under the overall corridor scale,local corridor scale and grid scale to reveal the reasons for the mismatch between supply and demand.Finally,the use of ESAI--ESTI index and cold hot spot analysis tools for regional division,to explore the optimization strategy,in order to provide theoretical support and methods for the planning and construction of Xiaoqing River corridor.The main results of this study are as follows: in terms of the quantification of supply and demand,the distribution of water ecosystem service supply is "high in the east and low in the middle",and the distribution law of demand service is "high in the east and low in the west".The results are greatly influenced by natural factors such as rainfall,soil type distribution,geomorphological features,vegetation coverage and social factors such as urban construction degree and population vitality;in the equilibrium analysis of supply and demand,the number of supply and demand services is balanced under the overall corridor scale,the spatial difference between supply and demand matching within the corridor is obvious,and the areas with better matching state of supply and demand are mainly distributed on the west side of the corridor.Combined with the results of cluster analysis,the areas with high population density show a high mismatch between supply and demand on the grid scale,and the areas around the blue-green infrastructure show a state of over-supply and demand.In terms of optimization strategy,river corridors should be systematically protected,green infrastructure networks should be constructed and corridor landscape construction should be strengthened;key ecological protection areas should be clearly defined and ecological restoration measures should be implemented reasonably at the local corridor scale.Ecological function zoning should be delineated on the grid scale,and ecological zoning management and control should be strengthened.