长江口及邻近海域无脊椎动物群落结构及其生物多样性研究

Community Structure and Biodiversity of Invertebrate Resources in the Yangtze River Estuary and its Adjacent Waters

根据2006年6月、8月和10月长江口及邻近海域无脊椎动物的底拖网定点捕捞调查资料,研究区域内无脊椎动物的群落结构及其生物多样性。调查共捕获无脊椎动物49种,共2232.277kg、1037641尾。分析了调查区域内虾类、蟹类、头足类及口虾蛄4个类别的生物量及密度组成,虾类在密度组成中占主导地位,占总密度的90.1%,蟹类在生物量组成中占主导地位,占总生物量的58.2%。运用相对重要性指数(IRI)研究不同种类的生态优势度,细点圆趾蟹(1822.64)为6月份的唯一优势种,双斑蟳(1573.90)及中华管鞭虾(1135.36)为8月份优势种,三疣梭子蟹(3667.30)、鹰爪虾(1568.35)及口虾蛄(1248.70)为10月份优势种。使用多样性指数D、H′、J′分析了该水域无脊椎动物群落的多样性,发现在3个航次调查中,10月份多样性指数最高;在不同调查区域,长江口中部多样性指数最高。采用Bray-Curtis指数CN比较了长江口不同区域的无脊椎动物群落之间物种组成的相似性。结果表明,长江口中部及长江口南部种类组成相似性最高,CN=0.628;长江口北部和长江口南部种类组成相似性最低,CN=0.166。与历史资料对比,长江口及邻近海域无脊椎动物主要捕获种类变化不大,群落结构比较稳定。

Based on the data from bottom trawl surveys in June, August and October 2006, the community structure and biodiversity of invertebrate resources in the Yangtze River estuary and its adjacent waters were analyzed. Forty -nine species of invertebrate,with a total catch of 2 232. 277kg, 1 037 641 individuals, were caught. According to the analysis of the relative biomass and the relative density of shrimps, crabs, squids and squillas, shrimps accounted for 90.1% by the number of individuals, however, crabs accounted for 58.2% by weight. The ecological dominance of species in community was determined by the index of relative importance, the results indicated that Ovalipes punctatus （ 1 822.64） was the only dominant species in June, Charybdis bimaculata （ 1 573.90） and Solenocera crassicornis （1 135.36）were the dominant species in August, Portunus trituberculatus（3 667.30）, Trachypenaeus curvirostris （ 1 568.35 ） and Oratosquilla oratoria （ 1 248.70 ） were the dominant species in October. Three diversity indexes, including species abundance index（D）, Shannon -Wiener diversity index （H＇） and species evenness index （J＇）, were calculated to analyze the characteristics of diversity of invertebrate communities. The results showed that the diversity indexes in October were larger than that in June and August, and the diversity indexes were higher in the center of the survey area than that in the other survey area. Similarity index （CN） was higher between the center and the southern part of the survey （0. 628 ）, but lower between the northern part and southern part of the survey area （0. 166）. From above -mentioned, combined with data in 1980＇s, varations in invertebrate species in the Yangtze River estuary was not significant, and community structure was relatively stable.