Distinctiveness, rarity and conservation in a subtropical highland conifer

Juniperus blancoi is a rare subtropical conifer with a wide yet restricted distribution and three recognized varieties. In this study, its ecological and genetic exchangeability are tested based on morphological descriptions, habitat differences, size measures, growth form, population genetics estimates and phylogeography, using the trnC-trnD plastid DNA region. Populations show differences in their habitat and morphological characteristics. Phylogeographic structure indicates a complex evolutionary history of expansion, fragmentation, and isolation processes. This resulted in high haplotype diversity (h = 0.863) and differentiation values (Dest = 0.866 and Dest > 0.5 in most pairwise comparisons) and a clear geographic structure with well defined groups. As a consequence, although the species has only 8 known populations, it must be divided into at least five distinct conservation units. Thus protecting a rare species could imply the conservation of a complex evolutionary history of non-exchangeable populations.