基于生态廊道识别的拉萨河流域生态安全格局构建

Constructing ecological security pattern based on ecological corridor identification in Lhasa River Basin

构建生态安全格局对于保障区域生态安全、优化国土生态空间具有重要意义。以拉萨河流域为研究区,基于“生态源地-阻力面-生态廊道”的区域生态安全格局构建范式,评估流域土壤保持、水源涵养、固碳、生境质量四项生态系统服务,基于生态系统服务重要性分级识别生态源地;选择土地覆被类型、归一化植被指数、地形起伏度、坡度、距道路距离、距水体距离作为主要阻力因子,利用熵权法形成综合阻力面;利用Linkage Mapper工具基于最小成本路径理论识别生态廊道并判定生态节点,构建流域生态安全格局。结果表明:提取生态源地20个,总面积2531.42 km^(2),占研究区总面积的7.77%;生态廊道36条,总长度916.87 km,与拉萨河干流平行呈“二”字型分布;生态节点13个,集中分布在裸地、裸岩、低覆盖度草地等地类,构建以生态源地-生态廊道-生态节点组成的“面-线-点”结构生态网络。研究结果为拉萨河流域生态安全和生态经济协调提供数据支持,为区域生态保护与可持续发展提供科学参考。

Construction of ecological security pattern is of great significance for ensuring ecological security at regional scale.It takes an important role on optimizing ecological national land space.Taking Lhasa River Basin as the research area,the ecological security pattern paradigm was constructed based on the ecological source-resistance surface-ecological corridor at the region scale.Soil conservation,water conservation,carbon sequestration,and habitat quality were evaluated as key ecosystem services of the Lhasa River Basin.Ecological sources were identified by the importance grades of ecosystem services.Land cover types,normalized difference vegetation index,relief,slope,distance to roads,distance to water were selected as the main resistance factors.The comprehensive resistance surface was generated by calculating the weight of resistance factors using the entropy weight method.Ecological corridors were identified by using Linkage Mapper tool based on the least cost path theory.Ecological nodes were extracted on the basis of ecological corridors.The ecological security pattern of the Lhasa River Basin was constructed at the watershed scale.The results showed that 20 ecological sources were extracted,with a total area of 2531.42 km2.Ecological sources accounted for 7.77%of the total area of the study area.36 ecological corridors were extracted,with a total length of 916.87 km.The distribution pattern of ecological corridors was parallel to the main stream of the Lhasa River in shape of"two"in Chinese.13 ecological nodes were extracted,concentrated in bare land,bare rock and low coverage grassland in the Lhasa River Basin.Finally,a plane-line-point structure ecological network was formed,which composed of ecological sources,ecological corridors,and ecological nodes.The results provide data support for the coordination of ecological security and ecological economy in the Lhasa River Basin,and provide scientific reference for regionally ecological protection and sustainable development.