江宁县江滩钉螺空间分布特征分析

Spatial analysis of snails distribution in marshland of Jiangning county

目的 探讨江宁县江滩钉螺的空间分布特征。方法 应用地理信息系统结合空间扫描法检测江滩钉螺分布的空间聚集性 ,并进一步以变异函数对钉螺的空间分布特征进行定量分析。结果 地理信息系统可见 ,2 0 0 0年江滩钉螺孳生地主要分布在洲滩的沿江地区 ;同时空间扫描分析发现在江滩分别有 2个活螺和 2个感染螺的高聚集区 ,其螺密度明显高于周围地区 (P <0 0 0 1) ;进一步以变异函数分析显示 ,江宁县江滩钉螺在空间的分布存在自相关性 ,其分布变异呈球型模型 ,当距离小于 0 0 3 0 1时 ,钉螺在空间分布上的变异与距离有关 ,并可以通过变异函数来估计。同时钉螺在空间各方向上的分布有所不同。结论 江宁县江滩钉螺分布的空间聚集性及自相关性 。

ObjectiveTo explore the spatial distribution of oncomele nia snails in marshland of Jiangning county in 2000.MethodsThe Spatial Scan Statistics and the Geographic In formation System(GIS) were used to detect the spatial aggregation of Oncomelania hupensis in marshland of Jiangning County.And the semi-variogram was establishe d to analyze the spatial auto-correlation of snails's distribution.ResultsThe GIS for snail habitats showed that the habita ts in marshland mainly distributed along the Yangtze river in 2000.And the Spati a l Scan Statistics detected 2 spatial clusters for alive snails and 2 for snails infected by schistosome in marshland respectively.The further analysis demonstra ted that the semivariogram for the distribution of snails in spatial were spheri cal model,which means that the variation of snails distribution in spatial were related with the distance apart when the distance was less than 0.030?1 and the variation can be estimated by the semi-variogram.ConclusionThe spatial aggregations and auto-correaltion of alive snails indicated that there were some factors suitable for the survival of snails in marshland of Jiangning county.So the study on the spatial distribu tion of oncomelenia snails was very useful for the further research on the risk factors.