延河流域景观格局的演变、预测及优化——以陕西省延长县为例

Evolution, Prediction and Optimization of Landscape Pattern in Yanhe River Basin——A Case Study at Yanchang County, Shaanxi Province

[目的]分析了黄土丘陵沟壑区延河流域景观格局的演变,并对其进行预测及优化,为该区生态环境建设和管理提供理论支撑。[方法]以延河下游流域的陕西省延长县为例,在分析历年景观格局指数的基础上,使用CA-Markov方法对延长县景观格局演变进行模拟,借鉴人为干扰度分析了景观变化强度及方向,提出分级管控措施,并建立了景观安全格局。[结果]①2008-2017年延长县景观格局的分离度指数提高了2.1%,最大斑块指数降低了32.4%。②未来10 a林地景观比基年减少18.5%,草地面积提高了13.1%。③研究区极度、中高度、轻度生态恶化区分别占总面积0.3%,23.3%和48.4%。生态安全格局包括9个核心生态节点和21个一般节点。人为干扰度能够表征景观阻力。[结论]通过实行分级管控和构建景观安全格局,可以有效协调延长县三生空间布局和改善生态环境质量。

[Objective]The prediction and optimization of the landscape pattern evolution in Yanhe River basin of loess hilly-gully region were studied in order to provide support for the construction and management of the ecological environment in this region theoretically.[Methods]Taking Yanchang County of Shaanxi Province in the lower reaches of Yanhe River basin as an example,based on the analysis of landscape pattern index over the years,the evolution of landscape pattern in Yanchang County was simulated by CA-Markov method,so as to analyze the landscape-change intensity and direction from the perspective of human disturbance.The landscape security pattern was established and hierarchical management and control measures were proposed.[Results]①The division index of the landscape pattern in Yanchang County increased by 2.1%from 2008 to 2017,and the largest patch index decreased by 32.4%.②In the coming 10 years,the forest landscape was expected to decrease by 18.5%,and the grassland was expected to increase by 13.1%.③The extreme,medium and mild ecological degradation areas in the study area accounted for 0.3%,23.3%,and 48.4%of the total area,respectively.The landscape security pattern included 9 core ecological corridor and 21 general corridor.Human disturbance could represent the landscape resistance.[Conclusion]The implementation of hierarchical management and control,and the construction of landscape security pattern are of great significance for preventing the deterioration of the ecological environment in Yanchang County.