High population genetic substructure in Hypochaeris leontodontoides (Asteraceae), an endemic rupicolous species of the Atlas Mountains in NW Africa

Abstract

Hypochaeris leontodontoides is a rupicolous species endemic to the Atlas Mountains (Morocco), where it occurs in scattered populations. This study aims to understand the biogeographic structure of a high mountain species in a rather small area of NW Africa. We used Amplified Fragment Length Polymorphism (AFLP) to investigate the population structure and phylogeography of H. leontodontoides in 19 populations sampled from the entire species distribution range. Multivariate analyses including PCoA, UPGMA analysis, and Bayesian clustering were applied to infer the influence of past biogeographic events. The AFLP differentiation among the populations was high (FST = 0.508). A significant geographical pattern by mountain region was found. The different phylogeographical analyses revealed four main groups corresponding to four well-defined geographic regions: Middle Atlas, Eastern High Atlas, Central High Atlas, and Western High Atlas, and highlighted the Western High Atlas as the most divergent group. Our data also indicate two regions as refuges during the Pleistocene ice ages: the Middle Atlas and the northernmost area of the Western High Atlas.