长江口新生湿地大型底栖动物群落时空变化格局

为了解长江口新生湿地大型底栖动物时空变化格局,2004年11月—2005年10月对九段沙湿地的3个沙洲以及各主要生境进行了调查。结果表明:九段沙湿地大型底栖动物密度和生物量均呈春季最高,夏、秋季下降,秋季末和冬季回升的趋势,整体生物多样性水平较低,分布不均匀。夏季上沙和中沙底栖动物密度存在显著差异,四季生物密度和生物量空间梯度为下沙>上沙>中沙。由物种组成分析可知,九段沙湿地大型底栖动物群落时空变化与优势种的消长有关。各季海三棱藨草带和藨草带底栖动物密度和生物量最高,芦苇和互花米草次之,光滩区域最低,且群落季节波动大。外来物种互花米草生境下底栖动物群落特征与土著种芦苇生境下无显著差异。

Temporal and spatial fluctuation of macrobenthos community in a newly established wetland in Yangtze River Estuary

To understand the temporal and spatial fluctuations of macrobenthos community in a newly established Jiuduansha wetland in Yangtze River Estuary,an investigation was made on the main habitats of three shoals in the wetland from November 2004 to October 2005.The results showed that the macrobenthos community in the wetland had the highest biomass and density in spring,which declined in summer and autumn and went up in late autumn and winter.The overall diversity of macrobenthos species was relatively low and distributed unevenly.There was a significant difference in macrobenthos densities between Shangsha and Zhongsha in summer,and the spatial grads of macrobenthos density and biomass was in the sequence of Xiasha>Shangsha>Zhongsha in all seasons.The trade-off of dominant species groups had a significant effect on the temporal and spatial fluctuations of macrobenthos community.The density and biomass of macrobenthos were the highest in Scirpus mariqueter and S.triqueter and the second in Phragmites australis and Spartina alterniflora zones during the whole year,and the lowest with extensive seasonal fluctuation in intertidal mudflat zones.No significant difference in the community characteristics of macrobenthos was observed between alien S.alterniflora and native P.australis zones.