Institute for Marine and Antarctic Studies, University of Tasmania, Launceston, 7250, Tasmania, Australia.
Environmental Research Institute, University of Waikato, Hamilton, New Zealand.
Sci Rep. 2017 Jul 12;7(1):5173. doi: 10.1038/s41598-017-05470-2.
Reduced competition is a frequent explanation for the success of many introduced species. In benthic marine biofouling communities, space limitation leads to high rates of overgrowth competition. Some species can utilise other living organisms as substrate (epibiosis), proffering a competitive advantage for the epibiont. Additionally, some species can prevent or reduce epibiotic settlement on their surfaces and avoid being basibionts. To test whether epibiotic pressure differs between native and introduced species, we undertook ex situ experiments comparing bryozoan larval settlement to determine if introduced species demonstrate a greater propensity to settle as epibionts, and a reduced propensity to be basibionts, than native species. Here we report that introduced species opportunistically settle on any space (bare, native, or introduced), whereas native species exhibit a strong tendency to settle on and near other natives, but avoid settling on or near introduced basibionts. In addition, larvae of native species experience greater larval wastage (mortality) than introduced species, both in the presence and absence of living substrates. Introduced species' ability to settle on natives as epibionts, and in turn avoid epibiosis as basibionts, combined with significantly enhanced native larval wastage, provides a comprehensive suite of competitive advantages contributing to the invasion success of these biofouling species.
竞争减少是许多引入物种成功的常见解释。在底栖海洋生物污损群落中，空间限制导致过度生长竞争的速率很高。一些物种可以将其他生物用作基质（附生），为附生物提供竞争优势。此外，一些物种可以防止或减少其表面上的附生定居，并避免成为底生物。为了测试本土和引入物种之间的附生压力是否不同，我们进行了离体实验，比较了苔藓虫幼虫的定居情况，以确定引入物种是否比本土物种更倾向于作为附生物定居，而不是底生物。在这里，我们报告说，引入物种会机会主义地在任何空间（裸露的、本土的或引入的）上定居，而本土物种则强烈倾向于在本土物种附近定居，但避免在引入的底生物上定居或靠近。此外，在有和没有活体基质的情况下，与引入物种相比，本土物种的幼虫死亡率更高。引入物种作为附生物定居在本土物种上，反过来又避免作为底生物的附生，再加上显著增强的本土幼虫损耗，提供了一整套竞争优势，有助于这些生物污损物种的入侵成功。
