黄海南部及东海中小型浮游桡足类生态学研究Ⅱ.种类组成及群落特征

Study on ecology of meso-small pelagic copepods in the Southern Yellow Sea and the East China Sea Ⅱ. species composition and community characteristics

重点探讨黄海南部及东海(28°00′～34°00′N、121°00′～127°00′E)中小型浮游桡足类的种类组成和多样度以及与环境的关系。结果表明:鉴定到种的中小型浮游桡足类有71种,4季皆出现的种类比例高达83.1%,种类季节变化不大明显。种数平面分布呈南部高、北部低、外海高、近海低的分布特征,种数分布与该海域水团势力消长相关,在水系交汇处,种类较多的往往位于暖流的一侧。4季共出现优势种15种(优势度Y≥0.02),主要有拟长腹剑水蚤(Oithonasimilis)、小拟哲水蚤(Paracalanuspar)和近缘大眼剑水蚤(Corycaeusaffinis)等,但在秋季,上述优势种类由尖额保猛水蚤(Aegisthusmucronatus),孔雀丽哲水蚤(Calocalanuspavo),锦丽哲水蚤(Calocalanuspavoninus)等替代。优势种更替率R值分析结果表明,黄海南部及东海调查区中小型桡足类群落所栖息的环境从夏季转至秋季的变化较大,从冬季转至夏季的变化相对较小。桡足类物种多样度(H′)、均匀度(J′)和单纯度(C)指数4季均值分别为2.58(2.27～2.99)、0.72(0.64～0.7)和0.26(0.21～0.38),H′值平面分布趋势与种数分布基本一致。

The relationship between community compositon and environmental condition of meso small pelagic copepods netted with mesh size 0.16 mm in the southern Yellow Sea and the East China Sea (28°00′-34°00′N、121°00′-127°00′E) was focally discussed in the paper. The experimental results show that there were 71 species of meso small pelagic copepods grown in four seasons, accounting for 83.1% of the total species. The seasonal variation in the community composition was not remarkable. More species existed in the southern part and oceanic sea, and less in the northern and nearshore waters. There were 15 dominant species appearing in four seasons, among them Oithona similis, Paracalanus parvus, Corycaeus affinis, etc were main dominants (dominance Y≥0.02) . In autumn,Aegisthus mucronatus,Calocalanus pavo , Calocalanus pavoninus, etc would be instead of the above species. The calculated value of alternative rate R for dominant species showed that the habitant environment for meso small copepods community in the investigated area varied greatly in summer turning to autumn and relatively less in winter turning to summer. The average value for species diversity ( H′), homogeneity (J′) and single purity (C) of pelagic copepods in four seasons were 2.58(2.27-2.99), 0.72( 0.64 -0.7)and 0.26(0.21-0.38) respectively. The horizontal distribution of H′value was basically correspondent to the species distribution.