Spatial-temporal Evolution And Prediction Of Ecosystem Carbon Storage In Shaanxi Province Based On Land Use Change

Under the background of "dual carbon",in order to better balance China’s carbon budget and expenditure,it is necessary to formulate a reasonable carbon emission reduction strategy and conduct regional carbon storage analysis.The study of the impact of land use cover change on carbon storage in terrestrial ecosystems can provide a certain reference for the improvement of regional carbon sink function,and has important theoretical significance for regional land use structure optimization and ecological civilization construction.Taking Shaanxi Province as the research object,the evolution of land use in time and space from2000 to 2020 was analyzed,the total carbon sequestration and carbon sequestration of different land types in the study area in the past 20 years were estimated based on the In VEST model,and the law of carbon storage accumulation in local grid space and the spatial distribution of carbon sources and sequestration areas in Shaanxi Province were explored.The FLUS model was used to predict the future land use change in Shaanxi Province,and the change of carbon storage service function under multiple scenarios was analyzed by combining the In VEST model.The results of the study showed that:(1)During the period from 2000 to 2020,the area of cultivated land and unused land continued to decline,the area of construction land and forest land continued to grow,and the area of grassland and water area showed a fluctuating upward trend.From the perspective of comprehensive land use dynamics,the land use dynamics in Shaanxi Province from 2000 to2020 showed an upward trend,and among all land use categories,the highest single land use dynamics were cultivated land,followed by construction land,and its land use area decreased significantly in 20 years.At the same time,there are significant differences in the conversion of land types,and the main land-use "source-sink" conversion relationship is manifested as cultivated land to forest land,grassland and construction land,and unused land into grassland and construction land.(2)From 2000 to 2020,the overall carbon storage in Shaanxi Province showed an upward trend,with the spatial distribution of carbon storage in the south and low in the north,and high or low in some areas.Among them,southern Shaanxi and central Yan’an are significantly higher,while Guanzhong urban agglomeration dominated by Xi’an and thenorthwestern part of Yulin are significantly lower.Arable land,woodland and grassland contributed greatly to the carbon storage of the ecosystem in the study area,and there was a positive correlation in the spatial distribution of carbon storage,the areas of HH-type high-value aggregation were mainly distributed in Qinba Mountain,eastern and western Yan’an,Hanzhong and southern Ankang,and the areas of LL-type low-value accumulation were mainly distributed in northwestern Yulin and Baoji,Xi’an and Weinan urban areas.The carbon sink area is mainly distributed in the Loess Plateau area in northern Shaanxi and the mountainous area in southeast Shaanxi,and the carbon source area is mainly distributed in the urban agglomeration of Guanzhong and northwest and southwest of Shaanxi.(3)The FLUS model was used to simulate the spatial layout of land use under natural development scenarios,cultivated land protection scenarios and ecological protection scenarios.Under the natural development scenario,part of the cultivated land in the adjacent areas of the town is encroached upon by construction land,and the area of forest land will increase due to policy support,but the area of grassland and unused land will decrease.Under the cultivated land protection scenario,the proportion of cultivated land converted to other land types has been limited to a certain extent,and the cultivated land area has increased,but the area of forest land and grassland has decreased to a certain extent.Under the situation of ecological protection,woodland and grassland have been well protected,and the rate of increase of construction land has decreased,which has maintained regional ecological security to a certain extent.Under the natural development scenario and the cultivated land protection scenario,the carbon storage in Shaanxi Province showed different degrees of decline,among which the carbon storage decreased slightly under the natural development scenario,the carbon storage loss in the cultivated land protection scenario was more,and the carbon storage in Shaanxi Province increased significantly under the ecological protection scenario.Therefore,while developing the economy,we should pay attention to the protection of cultivated land and ecological land,implement emission reduction and increase foreign exchange,and promote green and low-carbon development.