Ecological effects of introduced sessile marine invertebrates.

Manipulative field experiments were used to investigate the effects of the ascidians Botryllus schlosseri and Ascidiella aspersa and the bryozoan Bugula neritina on sessile invertebrate assemblages. Experiments were conducted on perspex plates suspended from Workshops Jetty, Williamstown, Victoria. All 3 introduced species affected the abundance of sessile marine invertebrates, but the effects were varied and not always negative or concentrated on native species. B. neritina increased the abundance of native species, A. aspersa increased the abundance of introduced species and B. schlosseri decreased the abundance of both native and introduced species. This research shows that effects of some introduced species are highly variable and do not conform to typical ideas that exist for introduced species.

本研究通过控制性野外实验，探究被囊动物（ascidian）皱瘤海鞘（Botryllus schlosseri）、聚柄海鞘（Ascidiella aspersa）以及苔藓动物（bryozoan）多室草苔虫（Bugula neritina）对固着无脊椎动物群落的影响。实验载体为悬挂于澳大利亚维多利亚州威廉斯敦工坊码头（Workshops Jetty）的有机玻璃板（perspex）。三种引入物种均对海洋固着无脊椎动物的丰度产生影响，但其效应存在显著异质性，并非始终为负面效应，也并非仅靶向本土物种。其中多室草苔虫（Bugula neritina，简写为B. neritina）可提升本土物种丰度，聚柄海鞘（Ascidiella aspersa，简写为A. aspersa）会增加引入物种的丰度，而皱瘤海鞘（Botryllus schlosseri，简写为B. schlosseri）则会同时降低本土与引入物种的丰度。本研究表明，部分引入物种的生态效应具有高度变异性，与学界关于引入物种的传统认知并不相符。