Data from: Multiple dispersal vectors drive range expansion in an invasive marine species

The establishment and subsequent spread of invasive species is widely recognized as one of the most threatening processes contributing to global biodiversity loss. This is especially true for marine and estuarine ecosystems, which have experienced significant increases in the number of invasive species with the increase in global maritime trade. Understanding the rate and mechanisms of range expansion is therefore of significant interest to ecologists and conservation managers alike. Using a combination of population genetic surveys, environmental DNA (eDNA) plankton sampling and hydrodynamic modelling, we examined the patterns of introduction of the predatory Northern Pacific seastar (Asterias amurensis) and pathways of secondary spread within southeast Australia. Genetic surveys across the invasive range reveal some genetic divergence between the two main invasive regions and no evidence of ongoing gene flow, a pattern that is consistent with the establishment of the second invasive region via a human-mediated translocation event. In contrast, hydrodynamic modelling combined with eDNA plankton sampling demonstrated that the establishment of range expansion populations within a region is consistent with natural larval dispersal and recruitment. Our results suggest that both anthropogenic and natural dispersal vectors have played an important role in the range expansion of this species in Australia. The multiple modes of spread combined with high levels of fecundity and a long larval duration in A. amurensis suggests it is likely to continue its range expansion and significantly impact Australian marine ecosystems.

外来入侵物种的定殖与后续扩散，现已被学界广泛认可为导致全球生物多样性丧失的最具威胁性的过程之一。这一现象在海洋与河口生态系统中尤为显著：伴随全球海运贸易的增长，此类生态系统中的入侵物种数量已出现显著攀升。因此，明确其扩散速率与扩散机制，成为生态学家与保护管理者共同关注的核心课题。本研究结合种群遗传学调查、环境DNA（environmental DNA, eDNA）浮游生物采样与水动力模型，对掠食性北方太平洋海星（Asterias amurensis）在澳大利亚东南部的引入模式与二次扩散路径展开了系统分析。针对该物种入侵分布区的遗传学调查显示，两个主要入侵区域间存在一定遗传分化，且未发现持续的基因交流迹象——这一格局与第二入侵区域通过人类介导的易位事件建立的假说高度吻合。与之相对，水动力模型与eDNA浮游生物采样的联合分析表明，区域内扩散种群的建立，与自然幼体扩散及后续种群补充过程相一致。本研究结果证实，人为与自然两种扩散途径，均在该物种在澳大利亚的分布扩张中发挥了关键作用。结合该海星极高的繁殖力与较长的幼体发育期，多种扩散模式的组合意味着其分布范围或将持续扩张，并对澳大利亚海洋生态系统造成显著冲击。