淮河干流软体动物群落结构及其与环境因子的关系

2011年3月、6月、9月和12月对淮河干流11个采集点的底栖软体类动物群落结构进行了调查研究, 共记录了软体类动物9科26种, 其中位于最上游的桐柏金庄种类最少, 仅有3种分布, 而位于中下游的新城口种类达到15种。总体上看, 自上游至下游, 软体动物种类的数量呈现一定的增多趋势。Pearson相关性检验结果表明软体动物种类数量和生物密度与河道深度间分别存在显著的正相关(r=0.617, P=0.043, n=11)和负相关关系(r=-0.654, P=0.029, n=11)。方差分析(One-way ANOVA)结果表明, Shannon-Wiener多样性指数F(3, 40) =0.225, P=0.879、Margalef丰富度指数F(3, 40) =0.902, P=0.449、Pielou均匀性指数F(3, 40) =0.841, P=0.479这3种指数以及生物量F(3, 40) =1.931, P=0.14不存在显著的季节性变化, 但生物密度F(3, 40) =5.45, P=0.003却存在极显著的季节性变化。其中, 生物密度在6月份出现峰值(90.13 36.31) ind./m2, 最低值出现在12月份(14.42 2.78) ind./m2; 生物量的变化不与生物密度变化同步, 其峰值出现在9月份(155.08 50.43) g/m2, 最低值则出现在3月份(39.15 14.08) g/m2。相似性分析(One-way ANOSIM)结果表明, 软体类动物群落在生物密度和生物量方面的优势物种组成上均无显著的季节性差异, 其P值分别为0.082和0.514。生物密度在不同月份间的不相似百分比变化幅度从53.87%至59.12%, 而生物量的不相似百分比变化幅度则从58.76%至68.58%。冗余分析(Redundancy Analysis RDA)结果表明, 河宽、水深和砂质型底质为影响淮河干流底栖软体类动物分布的主要环境因子。  

Community structure of benthic mollusca and its relationship with environmental factors in the mainstream of Huaihe River

The benthic mollusca community structure at eleven sampling sites in Huaihe River was investigated in March, June, September and December 2011. A total of 26 species from 9 families were recorded. Thereinto, only 3 species occurred in the first upriver site: Tongbaijinzhuang, and 15 species occurred in the downriver site: Xinchengkou. There were remarkable correlations between water depth and the number of species (r=0.617, P=0.043, n=11), and water depth and density (r=-0.654, P=0.029, n=11). Consequently, the number of species showed a certain increasing trend from upriver to downriver sites. The results of One-way ANOVA showed that there were insignificant seasonal variations in three biocenotic indices (Shannon-Wiener diversity index F(3, 40) =0.225, P=0.879, Margalef index F(3, 40)=0.902, P=0.449, and Pielou evenness index F(3, 40)=0.841, P=0.479) and biomass F(3, 40) =1.931, P=0.14, but not in density F(3, 40) =5.45, P=0.003. The mean maximal density (90.13 36.31) ind./m2 occurred in June while the minimum (14.42 2.78) ind./m2 appeared in December. different with the former, the mean maximal biomass (155.08 50.43) g/m2 occurred in September while the minimum (39.15 14.08) g/m2 appeared in March. The results of One-way ANOSIM showed that there was no remarkable seasonal change in mollusca community structure at density and biomass composition (both P 0.05). The average dissimilarity of density between months ranged from 53.87% to 59.12%, while from 58.76% to 68.58% in biomass. Redundancy Analysis (RDA) showed that river width, water depth and the type of substrate were the main environmental variables deciding the spatial distributions and species richness in Huaihe River.