涪江流域景观生态风险空间异质性特征分析

对涪江流域景观生态风险进行评估可以为该区域制定生态风险防控措施、提高生态系统服务功能提供科学参考。从“自然—社会—景观格局”3个维度选择海拔、土壤类型、地表覆被类型等10个景观生态风险胁迫因子构建评价指标体系,利用空间主成分分析(SPCA)、空间自相关分析等方法对涪江流域景观生态风险的空间异质性特征展开了研究。结果表明:(1)整体上涪江流域的景观生态风险等级呈西北部高于东南部地区,并呈集聚分布模式,其中在松潘、平武、北川、安岳、潼南等区县形成了“热点”区域,梓潼、游仙、盐亭、中江等区县形成“冷点”区域,主要受自然和景观格局维度因子影响较为明显;(2)研究区处于中度及以上风险等级区的面积为25 596.51 km²,占流域总面积的65.36%,主要分布于上游的松潘、平武、北川等县(区);(3)景观类型与生态风险等级空间分布有密切的联系,低度、较低生态风险区的分布与涪江干流走向契合。涪江流域景观生态风险的空间异质性特征明显,且面临的生态风险问题较大。

Analysis on Spatial Heterogeneity of Landscape Ecological Risk in Fujiang River Basin

The assessment of landscape ecological risks in the Fujiang River Basin can provide a scientific reference for the development of ecological risk prevention and control measures in the region and the improvement of ecosystem service functions. From the three dimensions of ‘nature-society-landscape pattern', 10 landscape ecological risk stress factors, including altitude, soil type, and land cover type, et al., were selected to construct an evaluation index system, and spatial principal component analysis, autocorrelation analysis, and other methods were used to analyze the spatial heterogeneity of landscape ecological risk in the Fujiang River Basin. The results show that:(1)as a whole, the landscape ecological risk level of the Fujiang River Basin is higher in the northwest than in the southeast, and it has a concentrated distribution pattern; among them, the ‘hot spot' areas in Songpan, Pingwu, Beichuan, Anyue, Tongnan and other districts and counties and ‘cold spot' areas in Zitong, Youxian, Yanting, Zhongjiang and other districts and counties have formed form, which are mainly affected by the dimensional factors of the natural and landscape pattern;(2)the study area is in the middle or above risk level area; the area is 25 596.51 km², accounted for 65.36% of the total area of the basin, mainly distributes in the upstream counties(districts)such as Songpan, Pingwu and Beichuan;(3)landscape types are closely related to the spatial distribution of ecological risk levels, and the distribution of low-level and lower ecological risk areas coincides with the direction of the mainstream of the Fujiang River; the spatial heterogeneity of landscape ecological risks in the Fujian River Basin is obvious, and the ecological risks faced by them are large.