浙江沿岸水域软体动物群落结构分析

ANALYSIS OF MOLLUSCS COMMUNITY STRUCTURE IN THE ZHEJIANG COAST

根据2019年全年4个航次浙江沿岸海域单船底拖网调查资料,分析了4个季节浙江沿岸海域软体动物的种类组成、优势种及资源密度分布,采用生态多样性指数、物种相似性指数(Js)、群落季节更替指数(AI)和迁移指数(MI)、丰度/生物量比较曲线(ABC曲线)分析了群落物种多样性、动态变化及其稳定性。结果表明:浙江沿岸海域全年共捕获软体动物62种,隶属于3纲,10目,32科。腹足纲(螺类)出现种类30种,占软体动物总种类数的48.39%;头足纲(头足类)出现种类19种,占软体动物总种类数的32.63%;双壳纲(贝类)出现种类13种,占软体动物总种类数的20.98%。软体动物群落优势种为长蛸(Octopus variabilis)、剑尖枪乌贼(Loligo edulis)、棒锥螺(Turritella bacillum)、多钩钩腕乌贼(Abralia multihamatai)和双喙耳乌贼(Sepiola birostrata),优势种的季节变化差异较大。浙江沿岸海域软体动物年平均资源密度为204.94 kg/km2,其中夏季平均资源密度为全年最高,冬季最低,资源密度空间分布特征总体上呈现由北向南逐渐增高的趋势。多样性指数(H′)、丰富度指数(D)及均匀度指数(J′)三种群落多样性指数均不高,软体动物群落多样性水平处于较低水平;物种相似性指数(Js)、群落季节更替指数(AI)和迁移指数(MI)分析,春冬季软体动物群落较夏秋季稳定;根据ABC曲线评估干扰对软体动物群落的影响可得:全年4个季节浙江沿岸软体动物群落均处于中等干扰状态。

Based on survey data collected in 4 seasons of 2019 by single bottom trawling of Zhejiang surrounding waters,the paper analysed species composition,dominant species and the distribution of resources density of molluscs.Ecosystem diversity index,Species similarity index(Js),Alternate index(AI),Migration index(MI)and abundance/biomass comparison curve(ABC curve)were adopted to analyse species diversity of community and its dynamic changes.The results showed that 62 molluscs species were captured belonging to 3 classes 10 orders,and 32 families,and the dominant species were Octopus variabilis,Loligo edulis,Turritella bacillum,Abralia multihamatai,and Sepiola birostrata all the year.The seasonal variation of dominant species was quite different.The annual average resource density was 204.94 kg/km~2,The resource density in summer was the highest value in the whole year,and Winter was the lowest.The average resource density was increasing gradually from north to south roughly.The annual average values of species abundance index(D),species diversity index(H′)and species evenness index(J′)were 0.70,0.88 and 0.61 respectively.Three indices values indicated that molluscs community diversity was on a low level.The values of Species similarity index(Js),Alternate index(AI)and Migration index(MI)indicated that the community stability was higher in spring and winter than in summer and autumn.According to the ABC curve,molluscs community all the year were moderately disturbed respectively.