中文摘要：

根据2008年9月至2009年8月在胶州湾中部海域逐月进行的底拖网调查数据，应用相对重要性指数、生物多样性指数和多元统计分析等方法对胶州湾中部海域蟹类群落结构及多样性的月变化及其影响因素进行了研究.结果表明： 调查海域共捕获蟹类18种，隶属于11科17属；蟹类相对资源量具有明显的月间变化，其中6—8月平均网获量较高.全年优势种为双斑蟳.蟹类群落优势种组成具有明显的月变化，双斑蟳、日本蟳、三疣梭子蟹、绒毛细足蟹和隆线强蟹分别为不同月份的优势种.蟹类群落物种丰富度指数（D）为0.54～2.86，Shannon多样性指数（H）为0.06～2.59，均匀度指数（J）为0.03～0.97.各群落物种多样性指数均在冬季月份最高，秋季月份次之，春夏季月份最低.聚类分析（CLUSTER）与非度量多维标度排序（MDS）分析可以将全年蟹类群落划分为3个月份组：Ⅰ（5—10月）、Ⅱ（4、11、12月）和Ⅲ（1—3月）.单因子相似性分析（ANOSIM）表明，不同月份组群种类组成差异显著；Ⅰ与Ⅱ、Ⅰ与Ⅲ组群差异显著，Ⅱ与Ⅲ组群差异不显著.各月份组群的典型种包括双斑蟳、三疣梭子蟹、日本蟳、隆线强蟹、绒毛细足蟹，以及月份组群间分歧种包括双斑蟳、日本蟳、三疣梭子蟹，对蟹类群落结构月变化的影响明显.生物-环境分析（BIOENV）显示，各环境因子中底层水温是影响胶州湾中部海域蟹类群落结构月变化的主要环境因子.

英文摘要：

Based on the monthly bottom trawl surveys in the central area of Jiaozhou Bay from September 2008 to August 2009, monthly changes and related affecting factors in community structure and diversity of the crab assemblages were examined using index of relative importance, ecological diversity indices, multivariate statistical analysis. In total, 18 crab species were caught and they belonged to 11 families, 17 genera. The relative abundance of crab varied dramatically among months, which was high in June, July and August. The dominant species composition of crab assemblage was observed to vary over months dramatically. The dominant species for the whole year was Charybdis bimaculata, and the dominant species in different specific months were C. bimaculata, C. japonica, Porttmus trituberculatus, Raphidopus ciliatus and Eucrate crenata. The ranges across months of the Margalef＇ s species richness index （D） , Shannon diversity index （H） and Pielou＇ s evenness index （J） of the crab community structure were 0.54-2.86, 0.06-2.59 and 0. 03-0.97, respectively. The diversity indices in winter months were the highest, and the diversity indices in autumn months were higher than in the spring and autumn months. MDS and CLUSTER analyses revealed that three groups/clusters, which were Group I （from May to October） , Group II （April, November and December） and Group III （January, February and March）, were identified for crab community during all the year in the central area of Jiaozhou Bay. ANOSIM analysis in community structure indicated that there were extremely significant differences among the groups, significant differences between Group I and Group II or between Group I and Group III, and no significant differences between Group II and Group III. Typifying species in the withingroup included C. bimaculata, P. trituberculatus, C. japonica, E. crenata and R. ciliatus, and discriminating species between groups included C. bimaculata, C. japonica and P. trituberculatus. These typifying and discrimina