基于FLUS-InVEST模型的北部湾城市群生态空间碳汇演变模拟及驱动因素研究

目的] 探究未来湾区城市群生态空间变化对碳汇的影响，找出变化背后的主要驱动因素，为城市群制定未来生态空间发展方向与策略提供参考，促进陆海新通道的科学开发。方法] 以北部湾城市群为例，基于2010，2015与2020年土地利用数据，使用GeoSOS-FLUS模型预测生态优先、耕地优先及城镇优先3种不同预设情境下2035年的北部湾城市群生态空间土地利用格局，使用InVEST模型对2020—2035年各情景下生态空间碳汇变化情况进行分析，使用地理加权回归找出影响土地碳汇变化的主要驱动因素。结果] 生态优先导向下2020—2035年北部湾城市群碳储量有所增加；城镇优先导向下碳储量降低较多，达到3.12×10⁶ t。坡度、人口密度和高程是城市群生态空间碳汇格局最重要的影响因素，城镇空间扩张是变化的主因。生态优先情景下，生态空间的土地将有所增加。结论] 生态优先导向能兼顾城镇发展与生态空间的环境保护需求，城镇优先导向和农业优先导向会大幅降低碳汇。另外政策措施也需尽早制定以抑制城镇空间扩张。

Evolution Simulation and Driving Factors of Eco-spatial Carbon Sinks in Beibu Gulf Urban Agglomeration Based on FLUS-InVEST Model

Objective] The impact of future changes in the ecological space of urban agglomerations in the bay area on carbon sinks were analyzed, and the driving factors behind the changes were identified in order to provide a reference for future ecological space development direction and strategies for urban agglomeration, and promote scientific development of new land-sea corridors.Methods] The GeoSOS-FLUS model was used to predict the ecological space land use pattern of the Beibu Gulf urban agglomeration in 2035 under three different scenarios (ecological priority, agricultural priority, and urban priority) based on land use data in 2010, 2015, and 2020. Changes in the spatial distribution of ecological carbon storage between 2020 and 2035 were analyzed using the InVEST model. Geographic weighted regression was used to identify the main drivers of change affecting land carbon sinks.Results] Carbon storage in the Beibu Gulf urban agglomeration increased under the ecological priority orientation from 2020 to 2035. Carbon storage decreased more under the urban priority, reaching 3.12×10⁶ tonnes. Slope, population, and elevation were the most important factors influencing the eco-spatial carbon sink pattern of the urban agglomeration, and the spatial expansion of towns was the main cause of changes. Ecological space will increase under the ecological priority scenario.Conclusion] Ecological priority orientation can balance the needs of urban development and ecological space protection, while urban development priority and agricultural priority orientations can significantly reduce carbon sinks. In addition, policy measures need to be developed as soon as possible to curb urban spatial expansion.