“Heat map” of distance matrix combined with a dendrogram. 1 – cluster 1, 2 – cluster 2, 3 – cluster 3 (Astragalo ciceri-Quercetum roboris), 4 – cluster 4 (Sanguisorbo officinalis-Quercetum roboris), 5 – Filipendulo vulgari-Quercetum roboris, 6 – Omphalodo scorpioidis-Quercetum roboris, 7 – Brachypodio pinnati-Quercetum roboris, 8 – Aconogono alpini-Quercetum roboris, 9 – Calamagrostio epigei-Quercetum roboris, 10 – Carici macrourae-Quercetum roboris, 11 – Pruno-Quercetum roboris, 12 – Bistorto majoris-Quercetum roboris, 13 – Lathyro nigri-Quercetum roboris, 14 – Chamaecytiso ruthenici-Quercetum roboris, 15 – Pyro pyrastris-Quercetum roboris, 16 – Vicio pisiformis-Quercetum roboris.