Ecological Benefit Evaluation Of Water Environment Restoration In Liaohe River Basin Of Jilin Province

The pollution and destruction of water environment has become one of the main environmental problems in the world.The ecological environment problems of Liaohe River Basin in Jilin Province are more prominent,the agricultural non-point source pollution is heavy,the ecological space is occupied,the ecosystem function is weakened,and the water environment is slightly polluted as a whole.In order to solve the problems of water shortage and poor water quality in Liaohe River Basin of Jilin Province,a series of water environment ecological restoration projects have been carried out in the basin since 2018,with a view to improving the quality of water environment.In order to evaluate the ecological benefits generated by the implementation of the project,,based on GIS technology and invest model,this study constructs an ecological benefit evaluation index system from the perspective of ecosystem services on the basis of land use changes in 2017 and 2020,selects ecosystem service indicators such as soil conservation,carbon storage and biodiversity,quantifies ecosystem service functions and analyzes temporal and spatial changes,The ecological benefits of water environment restoration are evaluated by using the method of environmental economics.The main conclusions are as follows:(1)The land use data of Liaohe River Basin in Jilin Province in 2017 and 2020were corrected,the law of land use change was analyzed.The results showed that during the study period,the area of cultivated land decreased by 1012.45 km~2;the areas of forest land and grassland increased by 3.58 km~2and 49.64 km~2,respectively,which were mainly converted from cultivated land;the area of bare land decreased by46.43 km~2,and 37.49 km~2was converted into grassland.The improvement of the ecological environment brought about by the implementation of the restoration project is relatively significant.(2)The ecosystem services in the study area showed the spatial distribution characteristics of high in the southeast and low in the northwest.From 2017 to 2020,the area with habitat quality index between 0.6 and 0.8 accounted for the largest proportion,and the habitat quality in the southeast improved significantly;the biodiversity index is low,about 89%of the regions are between 0.0～0.1,but the overall trend is increasing;the total carbon storage increased by 2.62×10~6tons,and the total soil conservation increased by 25.06×10~6tons.The total water supply increased by 289.962 billion cubic meters,the nitrogen and phosphorus retention increased by 15.46×10~4kg and 1.03×10~4kg respectively,and the grain output per unit area also increased.Only the functional capacity of the gas regulation service was reduced,and the amount of carbon fixation and oxygen release was reduced by 63.8kg,46.9 kg respectively.(3)From 2017 to 2020,the value of the seven ecosystem services showed an increasing trend,the value of water conservation services and carbon storage services increased the most,by 53.095 billion yuan and 2.225 billion yuan respectively.The ecological benefits of seven ecosystem services in the study area increased by 55.325billion yuan during the study period.This study could provide scientific support for the sustainable development of future ecological protection and restoration projects in Liaohe River Basin,Jilin Province.