Species composition and characteristics of macrobenthic fauna in Daya Bay,South China Sea
- 南海研究院-发表论文 
利用2008年4个航次在南海北部大亚湾海域开展的124个站次海洋生物调查资料,对大型底栖动物种类组成、优势种和特征种进行研究,结果表明:(1)大亚湾大型底栖动物群落季节变化显著、种类更替明显。2008年共采获大型底栖动物104科279种(类),各季种类平均更替率高达63%。(2)优势种组成较为稳定,单一种的优势地位显著。粗帝汶蛤(TIMOClEA SCAbrA)为大亚湾大型底栖动物第一优势种,周年均保持极高的优势地位。除粗帝汶蛤外还有毛头梨体星虫(APIOnSOMA TrICHOCEPHAlA)、脑纽虫(CErEbrATulInA SP.)、独毛虫(THAryX SP.)和中蚓虫(MEdIOMASTuS SP.)为大亚湾周年优势种,优势种组成较为稳定。(3)大亚湾大型底栖动物以多毛类为特征种类。多毛类在大亚湾海域大型底栖动物群落中具有重要作用,其代表和反映了整个群落的特征。(4)大型底栖动物种类组成情况反映了大亚湾海域环境状况。大亚湾大型底栖动物种类组成更替明显、特征种季节变化大,反映出大亚湾海域环境季节变化明显,尤其是春、夏和秋3季,秋、冬季较为稳定。优势种组成的年际变化表明,大亚湾海域生态环境发生了较大程度的变化。此外,多毛类在底栖动物群落中地位的突显,也反映出大亚湾海域营养水平的变化。对比历史资料分析,结论认为,大亚湾大型底栖生物种类数远低于历史水平,群落简单化趋势仍较为明显。虽然因采样区域和样品分选工具的差异,2008年种类远多于2004年调查结果,但仍低于1987年的473种。此外,1987年底栖动物的站均出现种数为50.6种/站,最高可达100种/站。2008年站均出现种数为15.0种/站,最高种数为38种/站,依然远低于历史水平。本研究旨在为系统开展大亚湾受损生态系统的恢复提供更为全面、丰富、准确的基础资料。The species composition,dominance and characteristics of macrobenthic fauna were studied within 124 sampling stations from four survey cruises in Daya Bay,South China Sea,during March,May,September,and December,2008.We found large seasonal changes in macrobenthic faunal community species composition.A total of 279 macrobenthic species were found in Daya Bay in 2008,with an average ratio of species seasonal subroga-tion of 63%.We also observed that the composition of dominant species was relatively stable among seasons,and mainly dominated by a single species.Throughout the year,the most dominant species was Timoclea scabra,fol-lowed by Apionsoma trichocephala,Cerebratulina sp.,Tharyx sp.and Mediomastus sp.The polychaete worms were characteristic macrobenthos in Daya Bay,where they have important ecological functions.It was also evident that the macrobenthic faunal composition in Daya Bay mirrored environmental conditions at each site.There were clear seasonal changes in subrogation species characteristics,which also reflected large seasonal changes in envi-ronmental conditions in Daya Bay,especially in spring,summer and autumn.Changes between autumn and winter were relatively small.The shift in dominant species composition within the macrobenthos in different years indi-cates long-term changes in environmental conditions in Daya Bay over the past 20 years.The increased dominance of polychaete worms over time suggests increased eutrophication in Daya Bay.Moreover,macrobenthic species richness was higher in recent years,and was associated with continued community structure simplification.The number of species in the 2008 samples(279 spp.) was lower than those in 1987(473 spp.).In 1987,the mean number of macrobenthic fauna in Daya Bay was 50.6 spp./station,with a maximum of 100 spp./station across sample stations.In 2008,the mean number of macrobenthic fauna was 15.0 spp./station with a maximum of 38 spp./station.