基于GIS空间自相关的深圳藁杆双脐螺分布特征

Investigation on the distribution characteristics of Biomphalaria straminea in Shenzhen based on GIS spatial autocorrelation

目的分析深圳藁杆双脐螺空间分布及时空变化特征,为科学评估曼氏血吸虫病传播和流行风险提供科学依据。方法基于螺的调查资料,应用全局空间自相关分析、局部空间聚集性分析等地理信息空间分析方法,开展深圳藁杆双脐螺时空分布特征研究。结果深圳藁杆双脐螺密度呈聚集性分布,全局自相关具有统计学意义(P<0.05),且空间上越邻近的区域藁杆双脐螺密度分布情况越相似;对调查点局部空间聚集性分析发现,藁杆双脐螺密度局部聚集性强的河流主要分布在近海岸区域,远离海岸的调查点螺密度聚集性不显著,且同一河流不同岸段调查点螺密度不一致,呈异质性,体现了河流内部环境的差异性对螺密度分布差异的影响;时空变化分析结果提示,水质是影响螺密度的重要因素,此外还与各区域内部的局部地理环境要素以及季节等密切有关。结论深圳藁杆双脐螺分布存在空间自相关和局部自相关,在空间上呈现一定的聚集性,分布特征与环境因素关系密切。

Objective To analyze the spatial distribution and spatial-temporal characteristics of Biomphalaria straminea in Shenzhen,and provide the evidence for monitoring the risk of schistosomiasis mansoni spreading.Methods The data of Biomphalaria straminea density of rives across Shenzhen area were collected. The spatial-temporal distribution characteristics of Biomphalaria straminea were analyzed by the GIS spatial autocorrelation and local spatial aggregation.Results The distribution areas of Biomphalaria straminea in Shenzhen are highly clustered. There is a significant global autocorrelation. The density distribution is similar of the snails in the adjacent area. The local spatial aggregation analysis of the survey point was applied. It was found that the rivers which were intense aggregations of the snail’distribution are mainly distributed in the coastal area,while the density aggregation is not different far from the coast. The snail density is inconsistent in the same river. It reflects the influence of the difference of the internal environment of the river on the difference of the snails’ distribution. The quality of the water is an important factor affecting the distribution of Biomphalaria straminea. The distribution is closely related to the local geographical elements and the seasons of the various regions.Conclusion The Biomphalaria straminea distribution in Shenzhen has global and local spatial autocorrelations. There was an intense aggregation of the snails’ distribution,which is obviously associated with the environmental factors.