The native status of Pinus pinaster on serpentine soils: charcoal analysis and palaeoenvironmental history in Sierra Bermeja (southern Iberian Peninsula, Spain)

Abstract

Pinus pinaster (maritime pine), a conifer native to the western Mediterranean, has a broad distribution, occupying a wide variety of habitats. On certain substrata such as ultramafic (ultrabasic) rock, the indigenous nature of this conifer has traditionally been questioned by the scientific community, which has regarded it as an introduction. In Sierra Bermeja, mountains forming the largest ultramafic outcrop in western Europe, the dominant woodland formations on serpentine soils are P. pinaster and Abies pinsapo. However the variable presence, albeit isolated, of various species of arboreal Quercus and the frequent forestry plantation of P. pinaster in recent centuries have led to broad-leaved woods being generally considered as the dominant natural communities in this mountain range, so marginalizing the role of these conifers. In an attempt to settle this scientific controversy, we have carried out soil charcoal analyses from seven localities in Sierra Bermeja. The palaeoecological data we have gathered show that P. pinaster has a natural status and has been present in this mountain range during a large part of the Holocene before the changes to its natural landscape by human activities. These results are of great importance for the management and conservation of rare serpentine ecosystems.