| Terrestrial ecosystem carbon is a crucial component of global carbon storage,which can effectively absorb atmospheric carbon dioxide and respond to global change.However,land use change has led to the spatial restructuring of terrestrial ecosystems,affecting their carbon sequestration capacity and becoming one of the main reasons for changes in ecosystem carbon storage.Therefore,simulating the spatial patterns of land use under different scenarios and time periods can evaluate the spatiotemporal distribution characteristics of carbon storage,provide scientific suggestions for optimizing land use structure,and avoid unreasonable land use practices that weaken the carbon storage capacity of the region.This study explored the terrestrial ecosystem carbon storage based on land use change.Using the Yangtze River Delta urban agglomeration as the study area,the spatial and temporal characteristics of land use changes from 2000 to 2020 were analyzed from three perspectives:structural change,dynamic degree change and transfer analysis.Based on the scenario weight matrices of Shared Socioeconomic Pathways(SSP)and Representative Concentration Pathways(RCP)extracted from LUH2(the Land Use Harmonization)data,the spatial and temporal distribution characteristics of land use in2030,2040,2050 and 2060 under different scenarios were obtained by combining the Markov-PLUS model.Besides,the spatial and temporal changes of carbon storage in the future period under different scenarios were obtained by combining the InVEST model.And the impacts of land use changes on carbon storage were explored by analyzing the shift of land use type gravity center and carbon storage gravity center under different scenarios and time periods,providing scientific suggestions for future development scenarios and land use planning in the region.The main conclusions of this study are as follows:(1)The land use types in the Yangtze River Delta urban agglomeration have shown different trends of change from 2000 to 2020.The land use structure in this area was dominated by woodland and cultivated land,but both have decreased in area over the past20 years.Cultivated land has decreased more significantly,mainly converted into built-up land.In addition,woodland and water have mainly been converted into cultivated land,reflecting the phenomenon of unreasonable encroachment of ecological land for cultivation.In contrast,the areas of grassland,shrubland,wetland,and bare land have fluctuated within a certain range,while the area of water has slightly increased.The rapid economic development of the Yangtze River Delta urban agglomeration has prompted built-up land expansion,inevitably causing encroachment on ecological land and causing a certain degree of damage to the ecological service functions of the region,with the landscape tending to be fragmented and the structure of land types becoming more and more unstable.(2)In the future period,under the SSP1-RCP2.6 scenario,the area of built-up land increases slightly,mainly expanding outward along the existing areas.The area of woodland increases,and the forest coverage gradually becomes denser.The areas of shrubland and wetland are relatively small,with no significant overall spatial changes.And the conversion of bare land and grassland to water and woodland,respectively,leads to a continuous decrease in their own area.Under the SSP2-RCP4.5 scenario,the overall spatial pattern is more stable with small changes.To be specific,the area of built-up land shows a trend of continuous expansion followed by stabilization.The changes in woodland are relatively small,while the area of grassland decreases due to being occupied by built-up land.And water,shrubland,wetland,and bare land do not show significant overall changes.Under the SSP5-RCP8.5 scenario,the area of built-up land continues to increase,with new large blocks of built-up land continuously added within the study area.The areas of cultivated land,grassland,and woodland also decrease significantly,especially the woodland in the western and southwestern regions,which changes from spatially contiguous to sporadically distributed,with greatly reduced coverage density and a significant decrease in area.At the same time,bare land continues to be converted into built-up land.Different scenarios have different demands for resources and different emphasis on ecological service functions,which lead to differences in the spatial and temporal characteristics of land use changes.(3)During the period from 2000 to 2020,the carbon storage in the ecosystem of the Yangtze River Delta urban agglomeration region continuously decreased,with an average annual decrease of 2.56×10~6 t C.Under the SSP1-RCP2.6 scenario,the ecosystem carbon storage of the region showed an increasing trend from 2020 to 2060,with an average annual increase of 6.39×10~6 t C,and the carbon storage in the region reaches 3890.04×10~6t C in 2060,effectively improving the ecological environment in the region.Under the SSP2-RCP4.5 scenario,carbon storage exhibited a slow increasing trend,with an annual average increase of 2.41×10~6 t C,reaching 3730.88×10~6 t C by 2060.The restoration level of ecosystem carbon sink capacity under this scenario is weak and the required restoration time is long.Under the SSP5-RCP8.5 scenario,the ecosystem carbon storage showed a continuous decreasing trend,with an estimated value of 3477.31×10~6 t C in 2060,and an average annual decrease of 3.93×10~6 t C.This scenario has a negative impact on ecosystem carbon storage and is unfavorable for sustainable development.Through the economic development data and greenhouse gas emission data,it can be inferred which scenario the society tends to be more inclined to,and based on the results of the study,timely countermeasures can be made to move toward the sustainable development path. |
