Classification of Caucasian oak (Quercus macranthera) forests from Dagestan (Eastern Caucasus)

A classification of Caucasian oak (Quercus macranthera) forests from Dagestan (Eastern Caucasus) using the Braun-Blanquet method has been developed. Three new associations were described: Ranunculo buhsei–Quercetum macrantherae ass. nov., Betonico macrantherae–Quercetum macrantherae ass. nov. and Calamagrostio arundnaceae–Quercetum macrantherae ass. nov. These communities are characterized by the leading role of sub-Mediterranean thermophilous species and Euro-Siberian meadow-steppe meso-xerophytes which allowed them to be assigned to the class Quercetea pubescentis Doing-Kraft ex Scamoni et Passarge 1959. The results of the study of ecological and plant-geographical properties of described communities revealed their unique feature – the presence of a large group of endemic subalpine Caucasian species. The combination of these ecologically contrasting species groups indicates moderately dry and continental climate of the oak (Q. macranthera) forests range in Dagestan and occurring them in the buffer zone between forest, steppe and alpine belts at altitudes of 1400–2100 m. Similar important ecological and floristic features are not typical for other forests of the class Quercetea pubescentis in Europe and Asia Minor. This made it possible to justify a new order Astrantio maximae–Quercetalia macrantherae ord. nov. containing a single alliance Astrantio maximae–Quercion macrantherae all. nov. Diagnostic species of the order and alliance are: Quercus macranthera, Astrantia maxima, Alchemilla sericata, Anthemis melanoloma, Betonica macrantha, Bupleurum polyphyllum, Calamagrostis arundinacea, Carum meifolium, Chaerophyllum aureum, Cephalaria gigantea, Centaurea salicifolia, Cicerbita racemosa, Erysimum armeniacum, Geranium sylvaticum, Heracleum asperum, Iris colchica, Lathyrus cyaneus, Lilium monadelphum, Medicago glutinosa, Primula macrocalyx, Viburnum lantana, Poa longifolia, Polygonatum verticillatum, Ranunculus buhsei, Rubus saxatilis, Primula ruprechtii, Psephellus dealbatus, P. daghestanicus, Pyrethrum leptophyllum, Pedicularis chroorrhyncha, Sedum oppositifolium, Trifolium canescens, Vicia grossheimii, Vincetoxicum funebre.