湖沼型地区钉螺种群的空间格局分析

Spatial Distribution Pattern of Oncomelania hupensis Population in Marshland and Lake Area

目的探讨湖沼型地区钉螺种群的空间格局。方法2005年10月、2006年4月及11～12月,随机选取安徽省池州市贵池区秋浦河沿岸的4块滩地设框查螺,分别计算钉螺的平均拥挤度(m*)、平均密度(m)、聚集指标[包括:扩散系数(C)、扩散型指数(Iδ)和聚集度指数(m*/m)]、Taylor的(lgS2-lgm)回归指数以及Iwao的m*-m回归指数。结果不同时间4块滩地钉螺的C、Iδ和m*/m指数均>1;Taylor的lgS2-lgm回归指数中的lgm与lgS2有明显的线性关系(r=0.972,P<0.01),lga=0.602,b=1.427;Iwao的m*-m回归指数中的m*与m呈明显的线性关系(r=0.984,P<0.01),α=2.367,β=1.617。结论湖沼型地区钉螺种群的空间格局为聚集分布,分布的基本成分是个体群。

Objective To explore the spatial pattern of the distribution of Oncomelania hupensis population in marshland and lake region. Methods Four bottomlands were selected randomly for the investigation along the Qiupu River in Guichi District, Anhui Province. The quadrats were placed randomly for snail survey, and the mean crowding, mean density, aggregation indices （diffusion coefficient（C）, morisita index（Is）, index of patchiness（m＊/m））, Taylor＇s power law and Iwao＇s m＊-m regression index were analyzed. Results For 4 bottomlands in different time, the diffusion coefficients, Morisita indices, and m＊/m indices were all more than one. There was a close linear relationship between the logarithm of the snail density and its variance （P〈0.01）, and the correlation coefficient was 0.972. In Taylor＇s power law, the lg a was 0.602 and b was 1.427. There was a close linear relationship between the mean crowding（m＊） and the snail density（m） （P〈0.01）, and the correlation coefficient, α and β was 0.984, 2.367 and 1.617 respectively. Conclusion The spatial pattern of Oncomelania hupensis population shows an aggregation distribution in marshland and lake region, and the basic components of snail distribution are in colonies.