2011-2020年长江口大型底栖动物群落结构变化趋势

对2011—2020年夏季长江口48个站位的大型底栖动物定量监测数据进行统计分析，研究长江口海域底栖生物群落时空结构演变特征。结果表明，近10年长江口海域共鉴定大型底栖动物284种，其中多毛类128种，占总种数的45.1%,甲壳类64种占22.2%,软体动物56种占19.7%,棘皮动物16种占5.6%,其他类合计20种。平均生物密度为(79.5±45.9)个/m²(年份变幅14.7—195个/m²)。平均生物量为(5.20±3.25)g/m²(年份变幅1.01—10.11g/m²),多毛类、软体动物、甲壳类是生物密度和生物量组成的主要类群。十年期间种类数、生物密度和生物量均呈现明显上升趋势，口外区贡献最突出。四个监测区域(南支、北支、杭州湾、口外)的优势种差异大。丝异须虫Heteromastus filiformis在各年份的优势种中出现的频度显著最大。总体来看，长江口监测区域大型底栖动物群落自然演变趋势向好。三项多样性指数统计结果表明，口外区大型底栖动物种类组成多样性水平显著高于口内三个区。生物群...

The variation of macrobenthos community structure in Changjiang River estuary from 2011 to 2020

Based on the quantitative data of macrobenthos in 48 sites, Changjiang River estuary from 2011 to 2020, the benthos community structure variation and spatial distribution were analyzed. It indicated that there were 284 species macrobenthos in Changjiang River estuary in past 10 years. It included 128 species of Polychaeta with the total percentage of 45.1%, 64 species of Crustacean with the total percentage of 22.2%, 56 species of Granulifusus kiranus with the total percentage of 19.7%, 16 species of Echinodermata with the total percentage of 5.6%, and 20 species of others. The average density was (79.5±45.9) ind/m²(interannual ranges was 14.7-195 ind/m²). The average biomass was (5.20±3.25) g/m² (interannual ranges was 1.01-10.11 g/m²). The species number, density and biomass increased significantly in the past decade, while sea area made a great contribution. The dominant species were very different in four areas (North branch, South branch, Hangzhou bay, and Sea area). Heteromastus filiformis was the dominant species with the highest frequency of occurrence in every year. Overall, the variation of macrobenthos community structure became better in Changjiang River estuary. Three diversity indexes indicated that the level of biodiversity in sea area was significantly higher than in other three areas. The lower diversity closely related to sediment types, Changjiang runoff hydrodynamics and engineering disturbance etc. Making the Abundance Biomass Comparison Curve (ABC curve), with the easternmost section (3 sites) in the sea area, the macrobenthos community structure was relatively stable and no clearly disruptions during the decade.