胶州湾冬季大型底栖动物群落结构及其与环境因子的相关性

Analysis of the characteristics of the macrobenthic community of Jiaozhou Bay in winter

为了解胶州湾大型底栖动物群落的动态变化以及与环境因子的关系,本研究通过2016年冬季在胶州湾12个站位采集到的大型底栖动物样品,共鉴定出大型底栖动物66种,其中环节动物32种,节肢动物、软体动物和棘皮动物分别为17种、9种和3种,脊索动物2种,纽形动物、头索动物、半索动物各1种。优势种为寡鳃齿吻沙蚕(Nephtys oligobranchia)、丝异须虫(Heteromastus filiformis)、青岛文昌鱼(Brachiostoma belcheri tsingtauense),优势度分别为0.02、0.147和0.024。大型底栖动物的总平均栖息密度为176.7 ind/m^2,总平均生物量为159.5 g/m^2。水平分布显示,栖息密度由高到低依次为湾内近岸海域、湾外海域、湾内离岸海域,生物量水平分布湾外海域>湾内海域。多样性指数(H')取值为1.19~3.54,平均值为2.65;丰富度指数(d)取值为0.91~2.29,平均值为1.47;均匀度指数(J′)取值为0.46~1.00,平均值为0.87。根据Cluster结果,可将调查站位划分为4个群落。ABC曲线显示,群落Ⅰ受到严重的扰动(H'=1.65),群落Ⅱ(H'=2.84)和群落Ⅲ海域(H'=2.32)有轻微的扰动,群落Ⅳ未受干扰(H'=3.54)。BIOENV分析表明,与群落结构关系最密切的环境因子为水深、溶解有机碳(DOC)、中值粒径和Zn含量(r=0.524)。胶州湾受人类活动干扰较多,大型底栖动物群落结构不稳定,需进行长期监测和评价。

To evaluate the relationship between the dynamic changes in the macrobenthic community and environmental factors in Jiaozhou Bay, macrobenthic samples were collected at 12 stations in the winter of 2016. A total of 66 specieswere identified in the survey area, including 32 species of Annelida, 17 species of Arthropoda, 9 species of Mollusca, 3 species of Echinodermata, 2 species of Chordata, and 1 species each of Nemertinea, Cephalochordata, and Hemichordata. There were 3 dominant species： Nephtys oligobranchia, Heteromastusfiliformis, and Branchiostoma belcheri tsingtauense, the dominance of which were 0.02, 0.147, and 0.024, respec-ively. The average abundance of macrobenthos was 176.7 ind/m2; annelid abundance accounted for 46.01% of the total abundance, arthropod abundance accounted for 17.84% of the total abundance, mollusk abundance accounted for 6.57% of the total abundance, and the abundances of the other phyla accounted for 28.58% of the total abundance. The average biomass was 159.5 g/m2 in the investigated waters; annelid biomass accounted for 6.42% of the total biomass, arthropod biomass accounted for 3.74% of the total biomass, mollusk biomass accounted for 76.56% of the total biomass, and the biomass of the other phyla accounted for 13.27% of the total biomass. The horizontal distribution of abundances showed that the abundance in the nearshore area of Jiaozhou Bay was the highest, followed by those of the area outside the bay and the offshore area of Jiaozhou Bay. The horizontal distribution of biomass showed that the biomass inside Jiaozhou Bay was higher than that outside the bay, in general. The value range of Shannon-Wiener index （H） of macrobenthos in the investigated area was 1.19-3.54, with an average value of 2.65; the value range of Margalef＇s richness index （d） was 0.91-2.29, with an average value of 1.47; the value range of Pielou＇s evenness index （J） was 0.46-1.00, with an average value of 0.87. According to the result of CLUSTER analysis, macrobenthos in the survey area could be divided into 4 groups （S7 and S10 for Group Ⅰ; S1, S2, S3, S4, S6, S8, S11 and S12 for Group Ⅱ; S5 for Group Ⅲ; and S9 for Group Ⅳ）. The abundance/biomass curves showed that Group 1 （H＇=1.65） was seriously disturbed, Group Ⅱ （H＇-2.84） and Group Ⅲ（H＇-2.32） were slightly disturbed, and Group Ⅳ （H＇-3.54） was not disturbed, which was consistent with the evaluation based on the Shannon-Wiener index （H＇） values. BIOENV correlation analysis showed that the best combination that most affected the community structure of macrobenthos was depth ＋ DOC ＋ median diameter ＋ Zn content, with a correlation coefficient （r） of 0.524. The macrobenthic community is unstable in Jiaozhou Bay owing to human activities, and needs long-term monitoring and evaluation.