Functional Evaluation Of Water Supply And Soil Conservation Based On The Land Use And In VEST Model In Changting County

Since the mid twentieth Century,with the human exploitation of the natural resources wantonly behavior,excessive development of the sharp deterioration of the ccological environment,the ecological environment has been irreversibly damaged,this behavior has also accelerated the degradation of ecosystem services.Through the quantitative evaluation of the change of land use types and ecosystem services,we can not only intuitively recognize the recent status of ecological restoration in the study area,but also analyze and decide the evaluation results.This paper takes Fujian province typical subtropical soil erosion in Changting County in Longyan city as the research sample,with 1989,1995,2000,2006,2010 and 2016 satellite images and data,quantitative analysis of land use change in this area since 1989,ecological management of every 5 years,and the use of InVEST(Integrated Valuation of Ecosystem Services and Trade-offs)model of water supply and soil conservation two ecosystem service function module for quantitative assessment.At the same time,the grade strength of the service area is divided and the comprehensive partition is added.The main results of the study are as follows:In the past 1989-2016 years,the pattern of land use and land cover change in Changting has changed greatly.The area of woodland increased by 14.69%from 2286km2 to 2622km2.The area of construction land is increased by 66.74%,the area of cultivated land is reduced by 15.05%,the area of garden land is reduced by 51.34%,the area of water area is reduced by 17.96%,the area of the bare land is sharply reduced by 94.51%,and it is reduced from 64km2 to 3km2.Other land use dropped by 86.81%from 268km2 to 35km2.The area of bare land has basically been eliminated and other unused land has been fully utilized.From the view of land use and overlying change transfer matrix,the area of woodland continues to grow,relying mainly on direct and indirect transformation of the rest of the land except water and construction.In all kinds of land,the conversion range of the rest is more than 50%,and the mutual benefit between the cultivated land,other land and construction land is more than 50%.The degree of conversion is high.In the 1989-2016 years and three periods,the water supply figures were 1067mm,1559mm and 2257mm respectively.The areas with strong water supply function in Changting county are mainly located in the area with high terrain around the basin,and the areas with poor water supply function mainly mainly in the central river field basin.In general,the total amount of water supply services in woodland is the largest,and the capacity of the bare larnd per unit area is the strongest,and the capacity of other land,construction land and water supply is less.The values of soil retention in 1989-2016 years and three periods are 19068t,23440t and 33284t respectively.The corresponding woodland areas with large soil retention are mainly distributed in the western,Eastern and southern regions around the Hetian basin,and the areas with less soil retention are mainly concentrated in the Hetian basin in the central region of Changting county.In general,the soil conservation function of woodland is the strongest,and that of water and construction land is the worst.In 1989,most of the districts in Changting county were divided into 0 grades,and the supply function of water supply was weak.In 2000,the water supply function of Changting County reached 1 level.In 2016,except for a small number of towns,the 2 levels of service functions were achieved.In 1989,the soil preservation function of Changting county was generally weak at the level of 1 levels.In 2000,the service function level in the surrounding area of Changting County reached level 1 or 2.In 2016,the level of soil conservation function of Changting County reached 2 levels.The three phase comprehensive zoning map of Changting county service f.unction is quite different.In 1989,the comprehensive service function level of the whole Changting county was weak.Besides the town,the other Changting counties had more than 1 and 2 of the comprehensive service functions.In 2000,the comprehensive service level of most areas remained above 2,and the comprehensive service function had been greatly improved.By 2016,the overall level reached a higher level.The service function level of most regions reached the highest level 4,and the comprehensive service function level was higher.