Understanding genetic diversity of relict forests. Linking long-term isolation legacies and current habitat fragmentation in Abies pinsapo Boiss

•Abies pinsapo maintained relatively high genetic diversity.•Local climate and land-use legacies were related to haplotype diversity.•Nuclear and chloroplast markers provide contrasting patterns of genetic diversity.•Bottlenecks and genetic drift evidences were found in all the studied populations.•Genetic erosion was not observed among cohorts of saplings, mature and old trees.