The non-native kelp, Undaria pinnatifida, is considered one of the world's worst invasive species. The northeast Atlantic is a hotspot of Undaria invasion, yet there is limited knowledge on its invasion dynamics. In the UK its distribution is strongly associated with artificial structures, primarily marina and harbour pontoons, with relatively few records of Undaria on natural substrates. Here, the southwest UK is used as a case region, to explicitly link Undaria distribution-abundance patterns in artificial marina habitats with those in natural rocky reef habitats. Using a mixture of in situ recording and video survey techniques, Undaria was found at all thirteen marina sites surveyed; but in only 17 of 35 rocky reef sites, all of which were in 2 of the 5 larger systems surveyed (Plymouth Sound and Torbay). The distribution-abundance patterns of Undaria at reef sites were analysed using zero-inflated models. The probability of finding Undaria on rocky reef increased with increasing proximity to marinas with high abundances of Undaria. Total propagule pressure from marinas also increased the probability of occurrence, and was positively related to Undaria abundance and cover at reef sites. Increases in the cover of native kelps, Laminaria spp., and wave exposure at reef sites were linked to a reduced probability of Undaria occurrence, and lower abundance and cover. Identifying high risk areas, natural boundaries and factors affecting the spread and abundance of non-native species in natural habitats is key to future management prioritisation. Where Undaria is confined to artificial substrates management may be deemed a low priority. However, the results of this study suggest that controlling the abundance and propagule pressure in artificial habitats may limit, to some extent, the spillover of Undaria into natural rocky reef habitats, where it has the potential to interact with and influence native communities.

中文翻译：

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环境和生态因素会影响非本地海带Undaria pinnatifida从码头到天然岩石礁群落的溢出。

非本地海带Undaria pinnatifida被认为是世界上入侵性最强的物种之一。东北大西洋是Undaria入侵的热点地区，但对其入侵动力学的认识有限。在英国，其分布与人工结构（主要是码头和港口浮船）紧密相关，在自然底物上的Undaria记录相对较少。在此，以英国西南部为案例区域，将人造码头栖息地中的Undaria分布-丰度模式与天然石礁栖息地中的Undaria分布-丰度模式明确关联。结合使用现场记录和视频调查技术，在所有被调查的十三个码头地点都发现了Undaria。但在35个礁石站点中，只有17个站点，所有这些站点都位于所调查的5个较大的系统中的2个（普利茅斯海峡和Torbay）中。使用零膨胀模型分析了Undaria在礁区的分布-丰度模式。在礁石上发现Undaria的可能性随着与Undaria丰富度较高的码头的距离增加而增加。来自码头的总传播压力也增加了发生的可能性，并且与Undaria的丰度和珊瑚礁位置的覆盖率呈正相关。天然海带，海带属物种的覆盖率增加，以及在礁石处的海浪暴露都与Undaria发生概率降低，丰度和覆盖率降低有关。识别高风险地区，自然界线和影响非自然物种在自然栖息地中扩散和丰富的因素，是未来管理优先重点的关键。如果将Undaria限制在人工基质的管理范围内，则可将其视为低优先级。然而，