福建三沙湾网箱养殖对多毛纲动物群落结构的影响

IMPACTS OF CAGE FARMING ON POLYCHAETE COMMUNITY IN SANSHA BAY,FUJIAN PROVINCE

利用东海近海典型网箱养殖海湾三沙湾9个航次数据,基于群落结构时空差异,阐释网箱养殖活动对多毛纲(Polychaeta)动物群落的影响。就群落组成而言,网箱养殖和非网箱养殖水域多毛纲物种组成存在差异,丝鳃虫科(Cirratulidae)和多鳞虫科(Polynoidae)分别是两种水域最占优势的类群;网箱养殖水域多毛纲优势物种的丰度及丰度比值略高于非网箱养殖区(104.06ind./m2>48.29ind./m2,57.59%>46.96%)。双因素方差分析(采样时间和养殖方式)结果表明,两种因素对物种数(S)、丰度(N)、生物量(B)、Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J′)、Margalef丰富度指数(d)等典型群落参数的交互作用不显著(P>0.05);考虑两种因素独立效应时,群落参数均无显著空间差异(P>0.05),但存在极显著时间差异(P<0.01)。双因素群落结构相似性分析(two-way ANOSIM analysis)表明群落结构无显著空间差异(P>0.05),但存在极显著时间差异(P<0.01)。典型对应分析(canonical correspondence analysis,CCA)显示pH、水深和溶解氧是影响三沙湾多毛纲动物分布格局的主要环境因子。上述结论显示,三沙湾网箱养殖活动对多毛纲动物群落结构已产生一定影响,主要表现在群落组成方面,群落结构和部分典型底栖环境因子具较强相关性。

Sansha Bay is one of typical cage farming waters in Chinese coastal waters. To elucidate cage farming effects on polychaete community in this area, we detected spatial and temporal differences in fauna composition, individual community parameter, and community structure, and analyzed relationship in community structure to typical environmental variables, using samples from nine cruises during May 2009 to January 2010. The results reveal that the species composition of polychaete fauna differed in cage and non-cage farming waters. Cirratulidae predominated in number in cage farming waters, whereas Polynoidae is dominant in non-cage farming areas. The abundance of dominant polychaete species and their percentages of total individual number had more advantages in cage farming waters than those in non-cage farming waters（104.06 ind./m248.29 ind./m2, 57.59%46.96%）. Two-way ANOVA analysis（cage farming and sampling time were selected as two factors） was employed to detect spatial and temporal differences in individual community parameters. The results reveal that the interaction of the two factors was not significant（P0.05）. In addition, community parameters showed no significant difference（P0.05） in the two different waters, but there were significant differences among cruises（P0.01）. Two-way ANOSIM analysis showed that no significant difference existed in community structure in the two different waters（P0.05）, but significant difference among sampling time were present（P0.01）. Canonical correspondence analysis showed that pH value, water depth and dissolved oxygen were the main environmental factors that affected the distribution pattern of polychaetes fauna in Sansha Bay. The conclusion shows that cage farming in Sansha Bay had affected the polychaete fauna to a certain extent, as reflected in community composition. Additionally, polychete community structure showed a strong correlation to major environmental factors in the bay.