新疆南部地区风沙扩散风险评价及景观格局优化

Risk assessment of sandstorm diffusion and landscape pattern optimization in southern Xinjiang

基于"致灾因子—孕灾环境—承灾体"3个维度,利用空间主成分分析法(SPCA)开展新疆南部地区风沙扩散风险评价,然后借助最小累积阻力模型(MCR)优化关键景观格局组分,构建多层次生态网络。结果表明:①区域致灾因子危险性较高,孕灾环境较为脆弱;和静县、阿合奇县生态本底较好,而盆地及其南部各县易于风沙扩散,尤其是和田地区、且末县及若羌县;绿洲人口和农业生产高度聚集,易损性较大。②46.53%的区域沙源丰富,立地条件差,风沙扩散风险较高。区域下垫面植被覆盖度和土壤类型是影响风沙扩散的最主要因素,风场强度是区域沙源扩散的主要诱因。③基于MCR模型,构建20条生态廊道连通生态源地,包括5条河流型、9条道路型和6条绿带型廊道;其中,1号和4号廊道纵贯塔克拉玛干沙漠,其余廊道沿塔里木盆地外缘呈圆环形分布;同时,判别出30个生态节点,包括A类生态节点7个,B类生态节点23个,主要分布在和田地区和巴州,可以通过建设防护林带、提高地表植被覆盖等措施降低风沙扩散风险。研究结果为中国北方干旱、半干旱地区风沙扩散风险防控与景观格局优化提供了技术支撑。

Based on the three dimensions of "hazard-formative factors, hazard-formative environments, hazard-affected bodies", we assessed the risk of sandstorm diffusion in the southern Xinjiang using the Spatial Principal Component Analysis(SPCA) method. A multilevel ecological network was built and components of key landscape patterns were optimized by the Minimum Cumulative Resistance(MCR) model.(1) The risk of hazard was high in this region by single dimension factor analysis. Under the action of wind, eight sandstorm source areas and Tarim Basin were prone to sandstorm diffusion because of the existence of abundant sand materials. The hazard-formative environment was relatively fragile. Hejing and Aheqi counties had relatively good ecological background. In the Tarim Basin and its southern counties, the sandstorm tends to spread, especially in Hotan Prefecture, and counties of Qiemo and Ruoqiang. Oasis population and agricultural production were highly concentrated and vulnerable to environmental factors.(2) Some 46.53% of the area had high risk of sand diffusion due to abundant sand sources and poor site conditions. The most important factors affecting the wind sand diffusion were vegetation coverage and soil types of the underlying surface. The main causes of regional sand source diffusion were the intensity of wind field.(3)Based on the MCR model, 20 ecological corridors were constructed to connect ecological source areas, including five river types, nine road types and six green belt types of corridors.Among them, corridors 1 and 4 connected via Taklimakan Desert, and the rest of the corridors presented a circular distribution pattern at the outer edge of Tarim Basin. At the same time, 30 ecological nodes were identified, including seven class-A ecological nodes and 23 class-B ecological nodes, which were mainly distributed in Hotan and Bayingolin prefectures. The risk of sandstorm diffusion can be reduced by constructing shelterbelts and improving vegetation coverage. Results provide technical support for the prevention and control of sandstorm diffusion and the optimization of landscape patterns in the arid and semi-arid areas of northern China.