天津近岸海域夏季大型底栖生物群落结构变化特征

Variation characteristics of macrobenthic communities structure in tianjin coastal region in summer

近年来,天津海岸带区域经济发展迅速,污染物排放量及污染海域面积持续增加,特别是2004年以来,天津港和临港工业区进行了大规模的海洋工程建设。由于具有迁移能力差、随季节波动不明显、生命周期相对较长等优点,大型底栖生物作为重要的人类干扰的反应指标,被广泛的应用于河口和海岸带生态系统对人类干扰的环境响应评价。为研究遭受人类干扰活动的天津近岸海域大型底栖生物群落结构的时空变化特征,分别于2004年和2007年夏季对渤海湾天津近岸海域进行了大面积的底栖生物群落调查。运用聚类分析、多维标度(MDS)及相似性分析(ANOSIM)等多元统计方法,分析了该区域底栖生物丰度、优势种、群落结构及生物多样性的时空变化特征。结果表明:1)2004年夏季底栖生物调查获得底栖生物29种,平均丰度为402.8个/m2,优势种为日本鼓虾、脆壳理蛤;2007年夏季底栖生物调查获得底栖生物36种,平均丰度为120.27个/m2,优势种为脆壳理蛤、小胡桃蛤、绒毛细足蟹、涡虫4种。2)2004年,调查区域底栖生物丰度空间分布呈现北低南高特征,2007年,则呈现中间低南北高的空间分布特征。3)2004年到2007年,位于大沽河口的19号站点底栖生物群落结构与其它站点存在显著性差异,生物群落受冲淡水影响明显,具有河口生物群落结构的独特性。2004年调查区域中的塘沽断面的底栖生物群落结构与其它四个断面存在显著性差异,而到2007年,五个断面底栖生物群落结构整体趋向一致。4)2004年,北部北塘、汉沽及南部岐口断面具有较高的丰富度、均匀度、多样性及较低的优势度指数,而到2007年,南部岐口、北部汉沽区域丰富度、均匀度和多样性指数均呈现下降趋势,而优势度指数则有所上升。中部区域特别是塘沽断面在丰富度、均匀度、多样性指数上有所增加,且越靠近中心区域增加程度越大。海岸工程、污染物排放、围垦养殖等人为干扰因素可能是造成天津近岸海域底栖生物丰度降低及其群落结构和多样性指数空间分布不均匀变化的主要原因。

With a rapid economic development in Tianjin coastal area recent years,the amount of land-based water pollutants and polluted area were increased consistently there.Especially since 2004,there were large scales coastal construction projects around Tianjin Port and Tianjin Lingang Industrial Zone.Due to the advantages of less migration capacity,slowly seasonal fluctuations and relatively long life period under the external environmental stressors such as human interferences,the large benthic organisms are widely used in evaluating the response of estuarine and coastal ecosystem variation as an important reaction indicator.To identify the main temporal and spatial characteristics of macrobenthic communities in Tianjin coastal region,which was affected by different anthropogenic activities,the macrobenthic community sample collections were conducted twice in the west Bohai Bay of Tianjin in August 2004 and in August 2007 respectively.Multivariate analysis methods of cluster analysis,multi-dimensional scaling（MDS） and analysis of similarity（ANOSIM） were utilized to analyze the characteristics of macrobenthic communities in Tianjin coastal region.The results showed that： 1） 29 macrobenthic species were collected and the average abundance was 402.8 ind/m2 in August 2004,and the dominant species were Alpheus japonicus and Thera fragilis.,36 macrobenthic species were collected and the average abundance was 120.27ind/m2,and the dominant species are Thera fragilis,Nucula paulula,Raphidopus ciliatus and Tubellaria in August 2007.The average abundance of macrobenthic decreased significantly from 2004 to 2007;2） In 2004,the spatial distribution pattern of macrobenthic abundance was lower in north and higher in south,while in 2007,the spatial distribution characteristics changed to the pattern of lower in middle and higher in north and south;3） From 2004 to 2007,there was a significant difference of macrobenthic community in 19# sample station which located near the Dagu River mouth,and affected by freshwater discharge to compare other stations.In 2004,there were significant differences of macrobenthic communities between Tanggu sections from other four sections.But this difference disappeared in 2007 and the community structure turned to be identical;4） In 2004,there were higher richness,evenness and diversity indices and lower dominance index in Beitang,Hangu and Qikou sections.In 2007,the richness,evenness and diversity indices in southern Qikou and northern Hangu area,which showed a decline trend,while the dominance index increased.But in the central survey region,especially in Tanggu section,the richness,evenness and diversity indices had increased rapidly.Anthropogenic activities,such as coastal engineering,pollutant discharging,and pond farming might be the dominant reasons which caused the drop of macrobenthic abundance and non-uniform spatial variation distribution characteristics of macrobenthic community structure and diversity indices in Tianjin coastal region.