长江口横沙岛、长兴岛潮间带大型底栖动物群落特征及其季节变化

Community characteristics and seasonal changes of macrozoobenthos in intertidal zones of Hengsha and Changxing islands at Yangtze River estuary

2006年秋季(10月)和2007年春季(4月)分别在横沙岛、长兴岛的9个断面采集土壤样本,分析了2岛大型底栖动物的群落特征及其时空变化格局。结果表明:在横沙岛、长兴岛共采集到大型底栖动物13种,分属4个主要类群,其中甲壳动物2种,软体动物3种,环节动物3种,其他动物5种。春、秋季之间大型底栖动物的密度和生物量不存在显著差异,两岛之间大型底栖动物的密度和生物量差异显著(P<0.05),横沙岛的密度和生物量大于长兴岛。2006年秋季,中潮位底栖动物的密度显著高于其他两个潮位(P<0.05);2007年春季,低潮位的密度显著低于其他两个潮位(P<0.05);而这两个季节各潮位之间的生物量均无显著差异。春季低潮位的生物量显著高于秋季(P<0.05),而高潮位和中潮位的生物量均无显著差异。春、秋季间和各断面间的多样性指数和均匀度指数都没有显著差异。Bray-Cutis群落聚类结果也表明各断面间的大型底栖动物群落不存在显著差异。

Macrobenthic faunas were sampled at nine sites in the intertidal zones of Hengsha and Changxing islands in October （autumn） 2006 and April （spring） 2007 to study the community characteristics and spatiotemporal pattems of macrozoobenthos in the study area. A total of 13 macrozoobenthos species were identified, belonging to Crustacea （2 species）, Mollusca （3 species）, Polychaeta （3 species）, and others （5 species）. The density and biomass of the macro- zoobenthos had less difference between spring and autumn, but had significant differences between Hengsha Island and Changxing Island （ P 〈 0. 05 ）, being higher at the sites of Hengsha Island. In autumn 2006, the density of macrozoobenthos was significantly higher in mid-intertidal zone than in high- and low-intertidal zones （P 〈 0. 05 ） ; while in spring 2007, this density was lower in low-intertidal zone than in the other two zones （ P 〈 0. 05 ）. However, the biomass of macrozoobenthos had no significant differences among the three intertidal zones both in autumn 2006 and in spring 2007. There were no significant differences in the biomass between seasons except for low-intertidal zone （P 〈 0.05 ）. The diversity and evenness indices of the macrozoobenthos had no significant differences between seasons and among sampling sites. Bray-Cutis and MDS analysis also showed that there were no significant differences in the macrozoobenthic cornmunities among the sampling sites.