Biodiversity and Structure of Undisturbed Mountain Siberian Pine Taiga of the Idarsky Belogorye Ridge (East Sayan)

The structure of flora and fauna, which is a standard of the state and dynamics of the taiga forests in humid climatic facies of the Altai-Sayan mountain region, has been analyzed based on the example of the undisturbed mountain Siberian Pine taiga (Eastern Sayan mountains). The ecological–phytocenotic features and floristic and faunistic composition of the late succession stage are studied. The dominance of the green moss group of forest types is revealed across the topographic profiles. The forest stands have a complex age structure with the dominance of Pinus sibirica Du Tour. and are characterized by low productivity (quality classes IV–V prevail), high class of normality (from 0.5 to 1.0), and sufficient regeneration. A floristic, ecological–coenotic analysis of the herb–dwarf-shrub layer, the elements of undergrowth, and the moss cover indicates the dominance of humid taiga flora. The species of the taiga ecological–coenotic group (ECG) (Vaccinium myrtillus, Carex iljinii, Calamagrostis obtusata, Gymnocarpium dryopteris, Phegopteris connectilis, Oxalis acetosella, Aegopodium alpestre, Trientalis europaea, Linnaea borealis, Maianthemum bifolium, Stellaria bungeana, et al.), moss–bog ECG (Ledum palustre, Vaccinium uliginosum, Carex globularis et al.), and bor-taiga ECG (Vaccinium vitis-idaea, Pyrola rotundifolia, Lycopodium annotinum et al.) form the herb–dwarf-shrub layer in the prevailing forest types. Green mosses (Hylocomium splendens and Pleurozium schreberi with a mixture of Ptilium crista-castrensis and Rhytidiadelphus triquetrus) dominate in the moss layer. Polytrichum commune, P. strictum, Dicranum scoparium, D. polysetum, and Sphagnum sp. mosses are found in some sites. The increased role of higher spore plants characterizes the flora as well-preserved archaic features flora. The Siberian pine forest coenoflora consists of 224 species and belongs to the Cyperaceae type. In the structure of the geographical elements of the flora, the leading role belongs to the Palaearctic, European, and Siberian elements with an increased role of endemics. The species typical for the Siberia taiga complex compose the core of the fauna. The most diverse avifauna is represented by 102 species (Tarsiger cyanurus, Parus montanus, Parus ater, Luscinia calliope, Sitta europaea, Loxia curvirostra, Coccothraustes coccothraustes, Tetrastes bonasia, Phylloscopus proregulus, etc.).