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.