Climatic oscillations of the Quaternary rapidly compelled plant species to shift their geographical range. How alpine plant species responded to climate change, however, remains elusive and remnants of the cold-adapted flora that currently strive in restricted ranges as small, isolated populations have been particularly overlooked. To address the evolutionary history of such a ‘glacial relict’, we here sampled and genotyped all known native populations of a narrow endemic species from the northwestern Alps, Papaver occidentale, as well as closely related taxa with double digest restriction-site Associated DNA (ddRAD) sequencing. Spatial patterns of genetic variation across populations coupled with insights from climatic niche modelling through time address underpinings of the long-term persistence of the species in face of climate changes. Evidence from population genetics and ecological modelling indicates that P. occidentale likely persisted through the last glacial maximum outside of the Western Prealps and that a major lineage recolonized the area from lower elevation, external regions. Differentiated lineages at the Northern margins of the species distribution range highlight highly divergent and geographically restricted populations that include considerable share of private markers and may indicate local glacial survival in isolated conditions. Our data thus imply that processes having shaped intraspecific spatial genetic structure within the Alps can be complex and lead to mosaic of populations with a mixed-history of local survival and immigration. A better understanding of spatio-temporal aspects of range contraction–expansion is crucial to shed light on processes underlying the evolution of remnant populations of such endemic species and set conservation priorities considering current climate changes.

第四纪的气候振荡迅速迫使植物物种改变其地理范围。然而，高山植物物种如何对气候变化做出反应仍然难以捉摸，由于特别孤立的小种群，目前在有限范围内奋斗的适应寒冷的植物群的残留物仍然难以捉摸。为了解决此类“冰川遗物”的进化史，我们在此对西北阿尔卑斯山，罂粟属，以及与双消化限制性位点相关DNA（ddRAD）测序密切相关的分类单元。跨种群遗传变异的空间模式，再加上从气候生态位建模到时间的洞察力，解决了面临气候变化的物种长期存续的基础。种群遗传学和生态学模型的证据表明，西方体育可能一直持续到西部Prealps以外的最后一次冰川最大期，并且主要的世系从较低海拔的外部区域重新定居了该地区。物种分布范围北部边缘的不同世系突出显示了高度分散和受地理限制的种群，其中包括相当大比例的私人标记，并可能表明在孤立条件下当地的冰川生存。因此，我们的数据表明，在阿尔卑斯山内形成特定物种内部空间遗传结构的过程可能很复杂，并导致具有局部生存和移民混合历史的种群镶嵌。