Port Curtis portwide macrobenthos study

Spatial patterns in benthic infaunal community structure of Port Curtis estuary (north-eastern Australia) were determined from quantitative grab samples and examined in relation to environmental variables. A total of 149 riverine, estuarine and open coastal stations were sampled during the survey, and 5744 individuals and 466 species dentified. Filter-feeding organisms (primarily polychaetes, molluscs and crustaceans) dominated the bedforms, and accounted for 50% of the total species abundance and 30% of the total species richness. Most taxa were uncommon, and 98% of species individually represented less than 2% of the total abundance. Distributional patterns in total species richness and abundance were highly correlated, and both parameters varied significantly with sediment structure. Numbers of species and individuals were typically highest in coarse-sand and gravel sediments, and lowest in fine, well-sorted, sands. Cluster analysis of species abundance data revealed nine community groupings characterised by small species subsets with restricted distributions. These groupings were found to be primarily related to measures of depth, salinity, dissolved oxygen and sediment structure. Not all variation in community structure was explained by these environmental variables, and it is likely that other unmeasured factors play an important role in determining benthic faunal composition in the estuary.

澳大利亚东北部柯蒂斯港河口的底栖内栖动物（benthic infaunal）群落结构的空间分布格局，通过定量采泥样（quantitative grab samples）进行测定，并结合环境变量开展关联分析。本次调查共采集149个河流、河口及开放沿海站位的样品，共计鉴定出5744个个体，分属466个物种。滤食性生物（主要类群为多毛类、软体动物与甲壳类）为底床生境的优势类群，其个体丰度占总丰度的50%，物种丰富度占总物种丰富度的30%。绝大多数分类单元较为稀有，98%的物种的个体数量均不足总丰度的2%。总物种丰富度与个体丰度的分布格局呈高度相关，且二者均随沉积物结构呈现显著变化：物种数与个体数通常在粗砂和砾石沉积物中最高，而在分选良好的细砂沉积物中最低。对物种丰度数据进行聚类分析（cluster analysis）后，得到9个群落类群，每个类群均由分布范围受限的小型物种子集所表征。进一步分析表明，这些群落类群主要与水深、盐度、溶解氧及沉积物结构等环境因子相关。但上述环境变量并未完全解释群落结构的全部变异，推测仍有其他未被测定的因子在调控该河口底栖动物群落组成中发挥重要作用。