| The service function of the aquatic ecosystem is a hot issue in the current ecological environment evaluation,which plays an important role in the survival and development of human beings and the protection of the ecological environment.The research on GIS,RS technology and related water ecological model has laid a solid technical foundation for the related hydrological ecological model and ecological service research in the space environment.Taking the Poyang Lake Basin as an example,this paper uses the Integrated Valuation of Environment Services and Tradeoffs(In VEST,Integrated Valuation of Environment Services and Tradeoffs)model to numerically analyze the spatial distribution of water quality and water production in the Poyang Lake Basin for more than 40 years.,and use Arc GIS technology to analyze it,analyze the trend of land use change from 1980 to 2018,and discuss natural geographical elements such as precipitation and terrain,as well as socioeconomic factors such as population,land use,and gross domestic product(GDP)and ecological factors.The relationship between the dynamic changes of the system service spatial pattern.Research indicates:(1)The water production in the basin gradually decreases from the northeast to the southwest.The eastern plains and hills have high yields,while the southwestern regions show low yields;due to natural geographical factors,the distribution of water resources in this region is closely related to GDP and population density.There are clear differences in the distribution patterns.Over the past 40 years,there has been an upward shift in production in the basin,and the location of peak production has shifted from the northeast to the south.Natural conditions such as precipitation,altitude,slope and other natural conditions have a greater impact on yield,and precipitation has the greatest impact on yield;social indicators such as population and GDP have an obvious positive relationship with yield changes.This is due to the development of urbanization.The increase in impermeable water layers,such as urban construction land,increases the production of the watershed.(2)The production of total nitrogen and total phosphorus in the Poyang Lake Basin from 1980 to 2018 showed an increasing trend year by year.There is a strong positive relationship between the changes of total nitrogen and total phosphorus production in Poyang Lake and urban land use,indicating that urban land use has a certain promoting effect on the contribution of total nitrogen and total phosphorus.The effects of forest and grassland on total nitrogen and total phosphorus yields have a significant negative relationship,indicating that woodland and grassland can effectively control the output of total nitrogen and total phosphorus in the Poyang Lake Basin,thus achieving the purpose of purifying the water body.Precipitation,altitude,slope and other natural conditions have a greater correlation with the content of total phosphorus and total nitrogen,and rainfall has the most obvious impact on total nitrogen.The output of total nitrogen and total phosphorus has a significant positive relationship with GDP,and can effectively improve the output of total phosphorus and total nitrogen.(3)Using the Reclassify technology of Arc GIS 10.5,the water conservation and water purification in the Poyang Lake Basin were classified.The results show that there are great differences in water conservation and purification at different levels.In addition,based on the spatial overlap analysis of water conservation and water quality purification,it is divided into 5 levels.The evaluation results show that the change of land use pattern plays an important role in improving the water conservation function,regulating yield and improving the ecological service function of the area.In the environmental governance project of the stable area,the protection and purification of water resources are divided and necessary,so as to achieve effective governance and maintenance. |
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