A survey of the Mediterranean broadleaved evergreen forests at the European scale

Mediterranean evergreen broadleaved forests are characterized by the dominance of evergreen oaks (Quercus ilex, Quercus suber, Quercus rotundifolia and Quercus coccifera). These forests are species-poor and, therefore, difficult to classify. Several poorly differentiated associations have been identified and grouped in alliances belonging to the Quercetalia ilicis order, which are main-ly defined based on ecological features but generally lack characteristic species. In this study, we analysed the forests and maquis dominated by evergreen oaks occurring in Mediterranean Europe with a modelling classification approach that was already successfully applied to the forest vegetation of the Italian Peninsula. This approach was applied on a matrix of 10,446 vegetation plots and 3458 species from the EVA database. We obtained a divisive classifi-cation at two optimum levels: at the higher level, 11 clusters were identified that can be consid-ered as suballiances; at the lower level, 46 clusters were considered corresponding to associa-tions. The distinctiveness of these clusters varies: several clusters were very well floristically char-acterized, whereas others were characterized by a combination of ecological features and spe-cies composition. Syntaxonomic evaluation of the results was conducted based on the compari-son with the currently accepted scheme for the European vegetation.