Climate change is rapidly affecting species distributions across the globe, particularly in the North Atlantic. For highly mobile and elusive cetaceans, the genetic data needed to understand population dynamics are often scarce. Cold-water obligate species such as the white-beaked dolphin (Lagenorhynchus albirostris) face pressures from habitat shifts due to rising sea surface temperatures in addition to other direct anthropogenic threats. Unravelling the genetic connectivity between white-beaked dolphins across their range is needed to understand the extent to which climate change and anthropogenic pressures may impact species-wide genetic diversity and identify ways to protect remaining habitat. We address this by performing a population genomic assessment of white-beaked dolphins using samples from much of their contemporary range. We show that the species displays significant population structure across the North Atlantic at multiple scales. Analysis of contemporary migration rates suggests a remarkably high connectivity between populations in the western North Atlantic, Iceland and the Barents Sea, while two regional populations in the North Sea and adjacent UK and Irish waters are highly differentiated from all other clades. Our results have important implications for the conservation of white-beaked dolphins by providing guidance for the delineation of more appropriate management units and highlighting the risk that local extirpation may have on species-wide genetic diversity. In a broader context, this study highlights the importance of understanding genetic structure of all species threatened with climate change-driven range shifts to assess the risk of loss of species-wide genetic diversity.

气候变化正在迅速影响全球的物种分布，特别是在北大西洋。对于高度流动且难以捉摸的鲸目动物来说，了解种群动态所需的遗传数据往往很稀缺。除了其他直接的人为威胁外，白喙海豚（ Lagenorhynchus albirostris ）等冷水专性物种还面临着由于海面温度上升而导致的栖息地变化的压力。需要解开白喙海豚在其分布范围内的遗传联系，以了解气候变化和人为压力可能在多大程度上影响整个物种的遗传多样性，并找到保护剩余栖息地的方法。我们通过使用白喙海豚当代范围内的大部分样本对白喙海豚进行种群基因组评估来解决这个问题。我们表明该物种在整个北大西洋在多个尺度上显示出显着的种群结构。对当代迁徙率的分析表明，北大西洋西部、冰岛和巴伦支海的种群之间存在非常高的连通性，而北海以及邻近的英国和爱尔兰水域的两个区域种群与所有其他分支之间存在高度差异。我们的研究结果对白喙海豚的保护具有重要意义，为划定更合适的管理单位提供了指导，并强调了局部灭绝可能对全物种遗传多样性造成的风险。在更广泛的背景下，这项研究强调了了解所有受到气候变化驱动的范围变化威胁的物种的遗传结构的重要性，以评估全物种遗传多样性丧失的风险。