Impacts of the Northern Pacific Seastar (Asterias amurensis) and European green crab (Carcinus maenas) on soft sediment assemblages in south east Tasmania

This study compared the individual and combined effects of two introduced marine species in SE Tasmania - the northern Pacific seastar (Asterias amurensis) and the European green crab (Carcinus maenas) - and investigated their impact on native invertebrate fauna using in situ caging experiments.Both species predate upon bivalves, and this study assessed the biological interaction between these introduced species and native bivalve species - allowing the impact of multiple exotic predator species to be investigated in one system.The cage experiments have 5 treatment groups, including all combinations of presence (single animal) and absence of seastars and crabs, and a control with neither. Predator activity (number and type of bivalves consumed) was recorded after 8 weeks by suction-sampling each cage and counting and identifying fauna.

本研究比较了塔斯马尼亚东南部两种引入海洋物种——北太平洋海星（Asterias amurensis）和欧洲绿蟹（Carcinus maenas）——的单独及联合效应，并通过原位围笼实验探究了它们对本地无脊椎动物群落的影响。这两种物种均以双壳类为食，本研究评估了这些引入物种与本地双壳类物种之间的生物相互作用，从而能够在同一系统中探究多种外来捕食者物种的影响。围笼实验设置了5个处理组，包括海星和螃蟹存在（单只动物）与不存在的所有组合，以及两者均不存在的对照组。8周后，通过对每个围笼进行抽吸采样、计数并鉴定动物群，记录捕食者的活动（被消耗的双壳类数量和种类）。