基于碳汇和景观连通性的跨流域生态安全格局构建

Construction of Cross-basin Ecological Security Patterns Based on Carbon Sinks and Landscape Connectivity

人工水系营造与土地利用变化对生态系统产生重要影响,利用碳汇和景观连通性构建跨流域生态安全格局对区域生态环境保护具有关键意义.选择湘江与漓江连通区域——湘漓连通区作为研究对象,基于2000~2020年土地利用数据,借助InVEST模型碳储量模块,结合形态空间格局分析(MSPA),采用MCR模型识别湘江与漓江连通区域生态安全网络,评价跨流域生态系统碳储量和生态安全格局时空演变特征.结果表明:①2000~2020年湘漓连通区土地覆盖类型主要为林地和耕地,土地利用变化表现为耕地、林地和草地面积减少,水域和建设用地面积增加.②湘漓连通区碳储量以高、中区域为主,呈现块状分布;受土地利用变化的影响,2000~2010年碳储量缓慢增加,2010~2020年碳储量逐渐流失,近20年总计减少1.832万t.③湘漓连通区生态源地(5块)面积先减小后增大,生态廊道(10条)长度先增大后减小.整体看来,随着城市化发展,湘漓连通区高阻力值地区逐渐向东北方向迁移,且呈现扩张趋势,生态安全格局重心向西南方向迁移.利用碳储量斑块和景观格局耦合分析生态源地动态分布及其稳定性,可以为跨流域复杂生态系统生态安全格局构建提供新途径.

Artificial water system creation and land use changes have great effects on ecosystems.The construction of cross-basin ecological security patterns based on carbon sinks and landscape connectivity plays a key role in regional ecological environment protection.The linkage area between the Xiang River and the Li River was selected as the research object.Based on the land use data from 2000 to 2020,this study examined the ecological security network of the Xiang-Li connected region using the InVEST model combined with morphological spatial pattern analysis(MSPA)and evaluated the temporal and spatial evolution of carbon storage and ecological security patterns.The results showed that:①From 2000 to 2020,the land cover types of the Xiang-Li linkage area were mainly forest land and arable land.The changes of land use types were characterized by decreases in arable land,forest land,and grassland and by increases in watersheds and construction land.②The carbon storage in the Xiang-Li linkage area was characterized by a blocky distribution,and the high and medium areas were dominant.The carbon stock increased slowly from 2000 to 2010 and decreased dramatically from 2010 to 2020,with a cumulative decrease of 18.32×10^(3) t due to the influence of land use changes.③The area of ecological sources(five in total)decreased firstly and then increased,whereas the length of ecological corridors(ten in total)increased firstly and then decreased in the Xiang-Li linkage area.Overall,in the process of urbanization,the distribution of the high ecological resistance value in the Xiang-Li linkage area gradually shifted to the northeast with an expansion,whereas the barycenter of the ecological safety pattern shifted to the southwest.Determining the dynamic distribution and stability of ecological sources by coupling carbon storage patches and landscape patterns can provide a new way to construct ecological security patterns in cross-basin ecosystems.