The making of a rapid plant invader: genetic diversity and differentiation in the native and invaded range of Senecio inaequidens

To become invasive, exotic species have to succeed in the consecutive phases of introduction, naturalization and invasion. Each of these phases leaves traces in genetic structure, which may affect the species' success in subsequent phases. We examine this interplay of genetic structure and invasion dynamics in the South African Ragwort (Senecio inaequidens), one of Europe's fastest plant invaders. We used AFLP and microsatellite markers to analyze 19 native African and 32 invasive European populations. In combination with historic data, we distinguished invasion routes and traced them back to the native source areas. This revealed that different introduction sites had markedly different success in the three invasion phases. Notably, an observed lag-phase in Northern Germany was evidently not terminated by factors increasing the invasiveness of the resident population but by invasive spread from another introduction centre. The lineage invading Central Europe was introduced to sites in w...

外来物种要实现入侵成功，需依次完成引入、归化与入侵三个连续阶段。上述每个阶段都会在种群遗传结构中留下印记，这些印记可能会影响该物种在后续阶段的入侵成功率。我们以欧洲扩散最快的植物入侵物种之一——南非狗舌草（Senecio inaequidens）为研究对象，探究其遗传结构与入侵动态之间的相互作用。我们采用扩增片段长度多态性（AFLP）和微卫星标记技术，对19个非洲原生种群与32个欧洲入侵种群进行了遗传分析。结合历史数据，我们厘清了其入侵路径，并将其溯源至非洲本土的起源区域。研究结果显示，不同引入点位在三个入侵阶段的入侵成功率存在显著差异。值得注意的是，德国北部曾观测到的种群滞缓期，显然并非因提升本土种群入侵性的因素而终结，而是通过另一个引入中心的入侵扩散得以打破。入侵中欧的该演化支最初被引入至以"w"开头的区域。