长江口横沙东滩围垦潮滩内外大型底栖动物功能群研究

2011年4月(春季)、7月(夏季)、10月(秋季)和12月(冬季)，在横沙东滩的围垦潮滩和自然潮滩进行底栖动物的采样调查，进行功能群划分及数量特征分析。在围垦潮滩和自然潮滩分别采集到底栖动物19种和22种。依据食性将其划分为浮游生物食者、植食者、肉食者、杂食者和碎屑食者5种功能群，围垦潮滩各功能群物种数分别为4，5，4，3，3；自然潮滩分别为6，3，5，6，2。围垦潮滩丰度由高到低依次为植食者>浮游生物食者>肉食者>杂食者>碎屑食者；自然潮滩为浮游生物食者>杂食者>肉食者>碎屑食者>植食者。围垦潮滩季节间仅有浮游生物食者和植食者的物种数存在显著性差异，潮位间仅有植食者的丰度存在显著性差异；自然潮滩季节间仅有浮游生物食者的丰度存在显著性差异，潮位间仅有植食者的物种数和丰度无显著性差异。围垦潮滩主导功能群在各潮位均为浮游生物食者和植食者；自然潮滩主导功能群由高潮带到低潮带变化为浮游生物食者→浮游生物食者和杂食者→杂食者。围垦潮滩浮游生物食者和植食者的Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数较高，而杂食者相对较低；自然潮滩杂食者和肉食者的3种多样性指数较高，而植食者相对较低。以上结果表明：围垦潮滩和自然潮滩底栖动物功能群的组成存在一定的差别；各潮位底栖动物功能群组成的不同与生境密切相关；围垦导致底栖动物群落以及功能群发生变化。

Macrobenthic functional groups at the reclamation and natural tidal flats of Hengsha East Shoal, the Estuary of Changjiang River

Functional groups of macrobenthos are vital for the assessment of the changes of ecological functions of wetland driven by natural and human factors. In order to get a better understanding of the functional groups of macrobenthos, the surveys were conducted in the reclamation tidal and the natural tidal flats of Hengsha East Shoal in April, July, October and December 2011. The results demonstrated that 19 species and 22 species were found in and outside the dyke, respectively. Based on their food preferences, the macrobenthos were classified into 5 functional groups: Planktophagous group, Phytophagous group, Camivorous group, Omnivorous group and Detritivorous group. The number of species in each functional group was 4, 5, 4, 3, 3 in the reclamation tidal flat, and 6, 3, 5, 6, 2 in the natural tidal flat. The abundance of each functional group in proper order was Phytophagous > Planktophagous > Camivorous > Omnivorous > Detritivorous in the reclamation tidal flat, and Planktophagous > Omnivorous > Camivorous > Detritivorous > Phytophagous in the natural tidal flat. The species number and abundance of each functional group were analyzed by the two-way ANOVA method. For the reclamation tidal flat, there was no significant difference among seasons for all of the species number and abundance except for the species number of Planktophagous group and Phytophagous group. Similarly, no significant difference was found among the tidal flats for the species number and abundance of each functional group except for the abundance of Phytophagous group. For the natural tidal flat, the difference was significant for the species number of Planktophagous group among the seasons, but not for others. However, most of the functional groups had significant difference among the tidal flats except for the species number and abundance of Phytophagous group. The Planktophagous group and Phytophagous group were the dominant functional groups at three tidal flats of the reclamation tidal flat. The dominant functional groups of the natural tidal flat, however, were Planktophagous at high tidal flat, Planktophagous and Omnivorous at middle tidal flat, Omnivorous at low tidal flat, respectively. In the reclamation tidal flat, Planktophagous group and Phytophagous group had the higher diversity indices (Shannon-Wiener index, Margalef index, Pielou index), while Omnivorous group had the lower diversity indices. In the natural tidal flat, Camivorous group and Omnivorous group had the higher diversity indices, while Phytophagous group had the lower diversity indices. In conclusion, the composition of functional groups between the reclamation tidal flat and the natural tidal flat was distinctly different. And the changes of the functional groups among the tidal flats were often associated with habitats. The reclamation had resulted in the variations of the communities and functional groups in macrobenthos.