干旱内陆河流域生态安全格局的构建及优化——以石羊河流域为例

生态安全格局识别及构建是保障干旱区生态安全、实现可持续发展的基本空间途径。石羊河流域是典型的干旱内陆河流域,其生态环境极为脆弱、敏感。基于石羊河流域生态本底特征,选取并定量评估水资源、生物多样性、水土保持和沙漠化4种生态系统服务,识别生态源地;以建筑物指数和植被净初级生产力为阻力因子,应用加权叠加法构建基本阻力面,并运用最小累积阻力模型及水文分析法识别生态廊道和生态功能节点,进行生态安全格局构建及优化。结果表明:(1) 2005—2015年,石羊河流域生态源地增加,生态环境质量趋于好转,特别是下游民勤绿洲区及上游祁连山区源地面积增加明显。2005、2010、2015年生态源地面积占流域总面积的比重分别为16.7%、14.7%、19.8%;(2) 2005—2015年,生态廊道明显增加,流域整体生态安全格局网络趋向复杂完善。2005年和2010年提取的生态节点都为36个,2015年的生态节点为35个,生态廊道从2005年的23条增加到2015年47条,部分潜在廊道发展演化为廊道;(3)基于2005—2015年生态安全格局分析,构建了以"二带区、三绿洲、五廊道、多中心"为核心的"绿洲廊道功...

Ecological security pattern construction and optimization in Arid Inland River Basin: A case study of Shiyang River Basin

The identification and construction of ecological security pattern is the basic spatial approach to guarantee the ecological security of arid areas and realize sustainable development. Shiyang River Basin is a typical Arid Inland River Basin with extremely fragile and sensitive ecological environment. Based on the ecological background characteristics of Shiyang River Basin, this paper selected and evaluated four ecosystem services, including water resources, biodiversity, soil and water conservation and desertification, to identify ecological source areas. Using a new index-based built-up index(IBI)and net primary productivity(NPP)as resistance factors, the basic resistance surface was constructed by the weighted superposition method. The ecological corridor and ecological function node were identified by the minimum cumulative resistance(MCR) model and hydrological analysis, and the ecological security pattern was constructed. The results showed that(1)from 2005 to 2015, Shiyang River Basin''s ecological source area increased, and the ecological quality improved, especially in Minqin oasis area in the lower reaches and Qilian mountain area in the upper reaches. In 2005, 2010 and 2015, the proportions of ecological source area in the total area of the basin were 16.7%, 14.7%, and 19.8%.(2)The spatial and temporal pattern of ecological corridor and ecological node showed that from 2005 to 2015, the total number of ecological nodes in Shiyang River Basin did not change significantly, while the number of ecological corridors increased significantly, and the overall ecological security pattern network in the basin tended to be complex and perfect. In both 2005 and 2010, 36 ecological nodes were extracted. In 2015, 35 ecological corridors were extracted. The number of ecological corridors increased from 23 in 2005 to 47 in 2015.(3) Based on the ecological security pattern analysis from 2005 to 2015, the optimal layout mode of "functional area of oasis corridor" with "two zones, three oases, five corridors, and multiple centers" as the core was proposed. This study provides reference and decision-making basis for ecological environment management and restoration, regional layout and planning of Shiyang River Basin.