Study On The Impact Of Land Use Change On Ecosystem Service Value In Tongcheng City Under Policy Guidance

Land is the carrier of ecosystem,which has the characteristics of soil,vegetation and other ecological environment;Ecosystem services are the foundation of human survival and development and are closely related to the well-being of regional residents.Human activities under the guidance of policies affect the land and affect the changes of ecosystem services.Therefore,it is helpful to understand the relationship between land use policy and ecological security,and provide scientific suggestions for the coordination of land use policy and ecological security.Firstly,the LDA model is used for quantitative classification of policy texts.Secondly,supported by RS data and Arc GIS technology,the land use change pattern of Tongcheng City under the influence of different policies is analyzed by means of land use dynamics and land use transfer matrix,and then the ecosystem service value is calculated to realize the expression of ecosystem service value in time dynamics and spatial visualization,It also analyzes the relationship between land use change and ecosystem service value from the aspects of correlation and variation contribution rate.Finally,it discusses the impact of different policies on the dynamic change trend of land use change and ecosystem service value in Tongcheng City,and puts forward suggestions for the future development,policy formulation and optimization of Tongcheng city.The main conclusions are as follows:(1)The text database is trained through LDA model,and the model confusion degree and py ldais library visualization are used to determine the optimal number of topics in the model.Each topic is composed of the core vocabulary under its topic.(2)From 2000 to 2021,the land use structure of Tongcheng city has changed significantly.Generally,forest land and cultivated land are the main land use structure,accounting for about 75%,the proportion of unused land is the lowest,and the number of construction land under the guidance of the government is increasing continuously;Forest land has the largest change in the transfer between different types.(3)The total value of ecosystem services in Tongcheng city shows a fluctuating trend of first increasing,then decreasing and then increasing.There are obvious differences in the spatial distribution of ecosystem service value.(4)Using correlation and variation contribution rate to analyze the relationship between land use and ESV,the relationship between them is significant,and the value of land use and ecosystem services changes significantly under the influence of different policies.In the future,we hope to put forward optimization suggestions and measures from the aspects of supervision,ecology and planning policies.