广西西江流域水源涵养服务空间格局及其影响因素

Spatial pattern and its influencing factors of water conservation services in Xijiang River Basin, Guangxi

[目的]水源涵养在众多生态系统服务中占据着重要的地位。揭示水源涵养服务空间格局及其影响因素,识别水源涵养服务重要区,对流域水资源利用、分区管理与综合保护具有重要意义。【方法】以广西西江流域为研究对象,基于InVEST模型、GeoDa与ArcGIS等工具,使用全域和局域空间自相关检验研究区水源涵养服务空间分布模式,构建空间误差模型辨识水源涵养服务关键影响因素,采用分位数分类法进行水源涵养服务重要性分级。【结果】广西西江流域多年平均水源涵养量为185.36 mm,2015年总量为376.10亿m^(3)。全域莫兰指数为0.769,表明研究区水源涵养服务在空间分布上具有空间依赖性。考虑到多重共线性的影响,最终从13项影响因素中筛选出7项进入空间误差模型,得出土壤饱和导水率、多年平均降水量、坡度、植被净初级生产力、经济密度对水源涵养服务产生显著正面影响,而人口密度和不透水率对水源涵养服务产生显著负面影响。识别出黔浔江流域及左郁江流域南部区域是水源涵养服务重要区,在相关政策制定与管理决策中需重点和优先考虑。【结论】广西西江流域水源涵养服务在空间分布上呈现集聚分布,并以低-低聚集和高-高聚集类型为主。土壤饱和导水率、多年平均降水量、坡度以及不透水率是水源涵养服务最主要的影响因素。

[Objective] Water conservation plays an important role in ecosystem services. This study aims to reveal the spatial pattern and its influencing factors of water conservation services and identify the important areas of water conservation services, which is of great significance to utilization, regional management and comprehensive protection of water resources in the basin. [Method] Taking Xijiang River Basin in Guangxi as the research object, with the support of the InVEST model, GeoDa, ArcGIS and other tools, the spatial pattern of water conservation services in the research area was tested by using global and local spatial autocorrelation,and the spatial error model was constructed to identify the key factors affecting water conservation services.Quantile classification method was used to classify the importance of water conservation services. [Result] The average annual water conservation capacity of Xijiang River Basin in Guangxi was 185.36 mm, with a total water amount of 37.61 billion m^(3) in 2015.The global Moran index was 0.769,indicating that the spatial distribution of water conservation services in the study area was spatially dependent.Considering the influence of multicollinearity,7 of the 13 influencing factors were finally selected into the spatial error model.The results showed that soil saturated hydraulic conductivity,annual average precipitation,slope,net primary productivity of vegetation (NPP) and economic density had significant positive effects on water conservation services,while population density and impervious surface rate had significant negative impacts on water conservation services.Qianxunjiang River Basin and the southern region of Zuoyujiang River Basin were identified as important areas for water conservation services,which should be prioritized in relevant policy making and management decision.[Conclusion]The spatial distribution of water conservation services in Xijiang River Basin in Guangxi presents a clustering distribution,dominated by low-low aggregation and high-high aggregation types.Soil saturated hydraulic conductivity,annual average precipitation,slope and impervious surface rate are the main factors affecting water conservation services.