Assessment And Forecasting Of Ecosystem Services In The Daqing River Basin Based On Climate And Land Use Changes

The construction of the Xiong’an New District is a significant historic strategic decision made by the central government of China,and adherence to ecological priority and green first is the key to the steady development of the Xiong’an New District.Baiyangdian is an important part of the blue-green space in the Xiong’an New District.For a long time,due to the continuous impact of climate change and human activities,Baiyangdian has been facing problems such as lack of water resources,pollution of the water environment,and sedimentation.Ensuring and improving regional ecosystem services is an effective way to deal with ecological and environmental problems,assess and predict the changes of water conservation,water purification,and soil conservation services at the basin scale,and analyze the impact of climate and land use changes on three key ecosystem services are of great significance to the protection of Baiyangdian ecological environment and the sustainable development of Xiong’an New Area.This paper first uses the four climate model prediction data of BCC-CSM-1-M,GFDLESM2 M,NCC-NORESM1-M,CSIRO-ACCESS1-3,Markov and Dyna-CLUE models,combined with the historical observations of climate and land use of Daqing River Basin,to analyze the historical changes and future trends of the climate and land use of the river basin.Based on this,water conservation service,water purification service and soil conservation service in the Daqing River Basin in 2000,2015,and 2035 were estimated and predicted based on the In VEST model.Finally,we explores the impacts of climate and land use changes on the three key ecosystem services of the basin by control variable analysis,and proposes suggestions for future ecological restoration of the Daqing River Basin.The results are as follows:(1)The climate change trend of the Daqing River Basin is mainly manifested as warmer and wetter.The annual mean temperatures and annual mean precipitation of the basin in the three periods of 1996-2005,2010-2019,and 2031-2040 are 12.67 ℃,12.74 ℃,12.79 ℃ and 459.31 mm,516.21 mm,523.65 mm,respectively;the land-use change in the basin between 2000 and 2015 was mainly characterized by rapid urban expansion,a significant decrease in farmland,an increase in forest and shrub area,and degradation of grassland.The prediction results show that the trend of land use change in the basin is basically unchanged from 2015 to 2035,but the change in the area of forest and farmland will increase due to the planting of plain forests and riparian forest belts,the forest area is predicted to increase by 1204.11km2,and the cultivated land area is predicted to decrease by 2620.15km2.(2)From 2000 to 2015,water conservation and water purification services in the Daqing River Basin increased,the total water conservation increased from 3.10×108m3to 4.04×108m3,the significant increase areas are mainly distributed in the western mountainous areas of the basin;the total non-point source nitrogen yield decreased from 7037.86 t to 6996.17 t,and the areas of significant decline were mainly distributed in the middle and lower reaches of the basin;soil conservation services declined,and the total sediment yield in the basin increased from 52.43×104t to 58.41×104t,the western mountainous region is the main decline area of soil conservation services.The prediction results show that from 2015 to 2035,the three key ecosystem services in the river basin will continue to change as before,the total water conservation will further increase by 0.21×108m3,the sediment yield will increase by 2.88×104t,and the area source nitrogen output will decrease by 784.75 t.(3)The analysis results of the control variables show that climate change is the main reason for the improvement of water conservation services and the decline of soil conservation services in the Daqing River Basin,with contribution rates ranging from129.09% to 139.71% and-121.03% to-118.26%,respectively.Land use change inhibited water conservation service,with a contribution rate ranging from-29.13% to-38.98%,mainly due to the reduction of grassland and farmland,and at the same time,land use change promoted soil conservation services,with a contribution rate Between-18.11% and 21.08%,mainly due to the increase of forest and shrub area.Land use change has played a major positive role in the improvement of water purification services,with a contribution rate from 122.01% to 126.94%,mainly due to the reduction of farmland and the planting of riparian forest belts.The contribution rate of climate change is-21.53% ~-27.13%,played a negative role on water purification services.(4)In response to the evolution of key ecosystem services and ecological environmental issues,this paper recommends that in the future ecological restoration of the Daqing River Basin,further increase the intensity of afforestation in the western mountainous areas of the basin,especially in the bare land of Datong City and sloping farmland in southern Zhangjiakou and northern Baoding;at the same time,strengthen the protection of grasslands in the basin,preferentially return farmland to grassland in flat areas;accelerate the planting of riparian forest belts in the plain areas in Daqing river basin,while strictly controlling the use of chemical fertilizers on farmland.