Severe disturbances can substantially alter eco-evolutionary processes and dynamics. While the impacts of catastrophic events on the biophysical attributes of communities are sometimes assessed, their effects on the genetic patterns of species remain poorly understood. To characterize how severe disturbances impact species at the molecular level, we examined the effects of the most energetic North Atlantic hurricane season in 50 years on the genetic diversity and structure of a dispersal-limited isopod, Gnathia marleyi. We sequenced a portion of the cytochrome oxidase I gene for 432 gnathiids, collected from six localities, ranging from western Puerto Rico to St John, US Virgin Islands. Importantly, multiple years of pre-hurricane sample collection allowed us to characterize temporal genetic patterns under undisturbed conditions and detect the changes subsequent to the 2017 hurricanes. Our results revealed no change to genetic diversity or structure for the years prior to the 2017 hurricanes, with genetic structure occurring at the local and regional levels, with three main clusters corresponding to Southwest Puerto Rico, East Puerto Rico, and the US Virgin Islands. However, directly following the 2017 hurricanes, genetic diversity increased at five of the six sampled localities. Additionally, we found a clear homogenizing effect prompted by increased shared genetic diversity among geographically distant regions and sites that resulted in substantially decreased among-region and among-site differentiation. Our work shows that severe disturbances caused by major tropical hurricanes facilitate gene-flow and increase overall genetic diversity and population admixture of dispersal limited coral reef species, potentially impacting the ecology and evolution of a key regional endemic.

严重的干扰可以极大地改变生态进化过程和动态。虽然有时会评估灾难性事件对群落生物物理属性的影响，但人们对它们对物种遗传模式的影响仍然知之甚少。为了在分子水平上描述严重干扰对物种的影响，我们研究了 50 年来最活跃的北大西洋飓风季节对有限扩散的等足类动物Gnathia marleyi 的遗传多样性和结构的影响。我们对从波多黎各西部到美属维尔京群岛圣约翰等六个地点收集的 432 只颌类动物的细胞色素氧化酶 I 基因的一部分进行了测序。重要的是，多年的飓风前样本收集使我们能够在不受干扰的条件下表征时间遗传模式，并检测 2017 年飓风之后的变化。我们的结果显示，2017 年飓风之前的几年，遗传多样性或结构没有变化，遗传结构发生在地方和区域层面，三个主要集群对应于波多黎各西南部、波多黎各东部和美属维尔京群岛。然而，2017 年飓风过后，六个采样地点中有五个的遗传多样性有所增加。此外，我们发现，地理上遥远的区域和地点之间共享遗传多样性的增加导致了明显的同质化效应，导致区域间和地点间的差异大大减少。 我们的工作表明，主要热带飓风造成的严重干扰促进了基因流动，增加了分散有限的珊瑚礁物种的总体遗传多样性和种群混合，可能影响关键区域特有物种的生态和进化。