In species that form dense populations, major disturbance events are expected to increase the chance of establishment for immigrant lineages. Real-time tests of the impact of disturbance on patterns of genetic structure are, however, scarce. Central to testing these concepts is determining the pool of potential immigrants dispersing into a disturbed area. In 2016, a 7.8 magnitude earthquake occurred on the South Island of New Zealand. Affecting approximately 100 km of coastline, this quake caused extensive uplift (several metres high), extirpating many intertidal populations, including keystone intertidal kelp species. Following the uplift, we set out to determine the geographic origins of detached kelp specimens which rafted into the disturbed zone. Specifically, we used genotyping-by-sequencing (GBS) approaches to compare beach-cast southern bull-kelp (Durvillaea antarctica and Durvillaea poha) samples to established populations throughout the species' ranges, and thus infer the geographic origins of potential colonists reaching the disturbed coast. Our findings revealed an ongoing supply of diverse lineages dispersing to the newly uplifted coastline, suggesting potential for establishment of "exotic" lineages following disturbance. Furthermore, we found that some drifting individuals of each species came from far-distant regions, some >1,200 km away. These results show that diverse lineages - in many cases from very distant sources - can compete for new space in the wake of an exceptional disturbance event, illustrating the potential of long-distance dispersal as a key mechanism for reassembly of coastal ecosystems. Furthermore, our findings demonstrate that high-resolution genomic baselines can be used to robustly assign the provenance of dispersing individuals.

中文翻译：

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SNP 分析揭示了地震隆起的海岸线潜在的殖民者的多样性。


在形成密集种群的物种中，重大干扰事件预计会增加移民谱系建立的机会。然而，关于干扰对遗传结构模式影响的实时测试却很少。测试这些概念的核心是确定分散到受干扰地区的潜在移民群体。 2016年，新西兰南岛发生7.8级地震。这次地震影响了大约 100 公里的海岸线，造成了大范围的隆起（几米高），消灭了许多潮间带种群，包括重要的潮间带海带物种。抬升之后，我们着手确定漂流到扰动区域的分离海带标本的地理起源。具体来说，我们使用测序基因分型（GBS）方法将海滩上的南部巨藻（Durvillaea antarctica 和 Durvillaea poha）样本与该物种分布范围内的已建立种群进行比较，从而推断到达该物种的潜在殖民者的地理起源。受扰的海岸。我们的发现揭示了不同谱系的持续供应分散到新隆起的海岸线，这表明在干扰后建立“外来”谱系的可能性。此外，我们发现每个物种的一些漂流个体来自遥远的地区，有些距离>1,200公里。这些结果表明，不同的谱系（在许多情况下来自非常遥远的来源）可以在异常干扰事件发生后争夺新的空间，这说明了长距离扩散作为沿海生态系统重组的关键机制的潜力。此外，我们的研究结果表明，高分辨率基因组基线可用于可靠地确定分散个体的来源。