Cork oak (Quercus suber L.) forests of western Mediterranean mountains: a plant community comparison

Abstract

Cork oak landscapes hold high socio-economic and biodiversity values. In the western Mediterranean they comprise open wood pastures as well as the denser forest stands that occur particularly in mountain regions. The aim of the current study was to compare the cork oak (Q. suber) forest vegetation of the Serra de Monchique (southern Portugal) with the more extensive formations of the Sierra del Aljibe (southern Spain). In particular, we sought to understand the degree of similarity of plant species composition and diversity components – species richness, endemicity and taxonomic singularity – between the two areas, with a view to establishing the importance of this vegetation type in its regional setting. We analyse vegetation plot data on vascular plant occurrence in the forests of the study areas through ordination and cluster analysis. Species richness, endemicity and taxonomic singularity are examined for the forest areas as well other common vegetation types in their vicinity. We find an overlap in species composition across Portugal and Spain, but also important local differences. In both areas, endemicity levels are low in comparison with other common vegetation types, but total and woody species richness is relatively high. We discuss these results in relation to previous comparisons between Aljibe and similar communities in the Tingitanian peninsula of northern Morocco. We conclude that the cork oak forests of this western Mediterranean region represent a conservation priority. They are faced with multiple threats, and their survival depends on a range of conservation approaches.