珠江口咸淡水池塘浮游动物群落结构特征及其影响因素

Zooplankton Community Structure and Its Influencing Factors in a Brackish-Water Pond on Qi’ao Island in the Pearl River Estuary

[目的]研究河口浮游生物生态较少涉及的咸淡水池塘这一小型特殊生境。[方法]选取珠江口淇澳岛红树林保护区内一人工池塘作为研究对象,通过4年的月季调查,分析其物种组成、生物多样性、群落结构特征及其主要影响因素,为河口湿地生境的保护、恢复提供数据支撑。[结果]共发现浮游动物100种(不含浮游幼体),其中轮虫为绝对优势类群,具70种,平均丰度为467.3个/L(17.0~1924.0个/L);群落结构分析可聚类为4个类群,且各类群之间都差异极显著(P<0.01),其差异主要由各类群的优势物种在月份间的丰度差异造成;各生物多样性指数[Margalef物种丰富度指数(D)、Pielou均匀度指数(J′)和Shannon-Wiener多样性指数(H′)]在类群间的总体差异均极显著(P<0.01);BEST/BIOENV和典范对应分析(CCA)都得出沉水植物(清塘导致沉水植物消失)、盐度、经济鱼类养殖活动等因素对浮游动物的群落结构影响显著,其中沉水植物消失影响最大。[结论]人为因素对淇澳岛咸淡水池塘生境的过度干扰,导致调查后期浮游动物物种多样性锐减,优势物种趋于单一化,群落结构已严重退化。

[Objective]Researches on estuarine zooplankton mainly focused on pelagic area,few papers on littoral small water bodies,such as estuarine ponds.[Method]In order to study this special habitat,an artificial brackish-water pond in the mangrove nature reserve on Qi’ao Island in the Pearl River Estuary was selected.The species composition,community structure characteristics and their main influencing factors were studied through four years of monthly sampling.[Result]100 species(excluding planktonic larva)were found in total,among which rotifer was the most dominant group,with 70 species recorded;the average total abundance was 467.3 ind./L,fluctuating between 17.0 ind./L and 1924.0 ind/L.The zooplankton community was classified into four groups by the Nonparametric Multidimensional Scaling Analysis(NMDS),and the differences of structure between the groups were all significant(P<0.01).It was mainly caused by the differences in the abundance of dominant species between months in each group.Margalef’s species richness index(D),Pielou’s species evenness index(J′)and Shannon-Wiener diversity index(H′)were all significantly different between groups(P<0.01).Both BEST/BIOENV and Canonical Correspondence Analysis(CCA)showed that submerged plants(the disappearance of submerged plants caused by mechanical cleaning of pond sediment),salinity,and economic fish aquaculture activities all had significant effects on zooplankton community structure,among which the disappearance of submerged plants had the greatest effect.[Conclusion]The excessive disturbance of the brackish-water pond on Qi’ao Island by human activities had led to a sharp decrease in zooplankton species diversity,the dominant species tended to be homogeneous and the community structure had been seriously degraded in the late stage of the survey.