Phlomis fruticosa scrublands in the central Mediterranean region: syntaxonomy and ecology

Phlomis fruticosa is a weakly lignified shrub which colonizes large expanses in Albania and Greece in overgrazed areas, and is also present throughout the northern Mediterranean region from Italy to Cyprus. It is characteristic for species-rich vegetation, with up to 65 species on 50 m2. We assembled a dataset of 129 original and published relevés and analyzed the floristic variability and the ecology of vegetation containing Phlomis fruticosa in the central Mediterranean region. We floristically and ecologically differentiated three previously described associations: a) the Salvio fruticosae-Phlomidetum fruticosae, distributed in Sicily, is characterized by high species richness of nano-phanerophytes, and is restricted to the warmest and more oceanic part of the range of P. fruticosa; b) the Sideritido italicae-Phlomidetum fruticosae is characterized by high chamaephyte richness, and occurs in cooler, relatively oceanic areas; c) the Allio pulchelli-Phlomidetum fruticosae is very rich in therophytic species and occupies the drier, more continental part of the distribution area of P. fruticosa. The vegetation syntaxa of the P. fruticosa scrubland belong to two structural types: a relatively low scrubland with a poorly developed herb layer on limestone boulders, and a taller, more open scrubland with a rich herb layer that grows in pastures and abandoned fields. Our results suggest that scree and boulders is the primary habitat of low-growing P. fruticosa scrublands (first structural type), from which the species colonized overgrazed areas and abandoned fields, after humans cleared the primeval Mediterranean forest.