Data from: Climate-driven range shifts explain the distribution of extant gene pools and predict future loss of unique lineages in a marine brown alga

The climate-driven dynamics of species ranges is a critical research question in evolutionary ecology. We ask whether present intra-specific diversity is determined by the imprint of past climate. This is an ongoing debate requiring interdisciplinary examination of population genetic pools and persistence patterns across global ranges. Previously, contrasting inferences and predictions have resulted from distinct genomic coverage and/or geographical information. We aim to describe and explain the causes of geographical contrasts in genetic diversity and their consequences for the future baseline of the global genetic pool, by comparing present geographic distribution of genetic diversity and differentiation with predictive Species Distribution Modeling (SDM) during past extremes, present-time and future climate scenarios for a brown alga, Fucus vesiculosus. SDM showed that both atmospheric and oceanic variables shape the global distribution of intertidal species, revealing regions of persistence, extinction and expansion during glacial and postglacial periods. These explained the distribution and structure of present genetic diversity, consisting of differentiated genetic pools with maximal diversity in areas of long term persistence. Most of the present species range comprises postglacial expansion zones and, in contrast with highly dispersive marine organisms, expansions involved only local fronts, leaving distinct genetic pools at rear edges. Besides unraveling a complex phylogeographic history and showing congruence between genetic diversity and persistent distribution zones, supporting the hypothesis of niche conservatism, range shifts and loss of unique genetic diversity at the rear edge were predicted for future climate scenarios, impoverishing the global gene pool.

物种分布范围的气候驱动动态机制是进化生态学领域的关键科学问题。本研究旨在探讨当前种内多样性是否由过往气候的遗留效应所决定，这一议题至今仍存在持续学术争议，亟需跨学科研究对全球分布范围内的种群遗传库与物种存续模式展开系统分析。过往相关研究因基因组覆盖范围与/或地理信息的差异，曾得出相互矛盾的推断与预测结果。本研究以褐藻囊泡墨角藻（Fucus vesiculosus）为研究对象，通过对比当前遗传多样性与分化的地理分布格局，结合过去极端气候时期、当前及未来气候情景下的物种分布模型（Species Distribution Modeling, SDM）预测结果，旨在阐明遗传多样性地理差异的成因及其对全球遗传库未来基线的影响。物种分布模型结果显示，大气与海洋变量共同塑造了潮间带物种的全球分布格局，揭示了冰期与冰后期的物种存续、灭绝与扩张区域。上述结果解释了当前遗传多样性的分布与结构特征：长期存续区域拥有最高的遗传多样性，并分化形成了独特的遗传库。当前该物种的分布范围大多属于冰后期扩张区域，与扩散能力极强的海洋生物不同，其扩张仅涉及局地锋面，在扩张后缘保留了独特的遗传库。本研究不仅阐明了囊泡墨角藻复杂的系统地理学历史，证实了遗传多样性与物种存续区域的一致性，从而支持生态位保守性假说；同时还预测，未来气候情景下物种分布范围将发生迁移，且扩张后缘的独特遗传多样性将出现流失，进而导致全球遗传库的遗传多样性降低。