Coenofloras of Taishet and Bratsk Districts of the Irkutsk Region (East Siberia)
Authors:   Institute of General and Experimental Biology SB RAS, Kharpukhaeva T. M. , Afanasyeva L. V. ,   Institute of General and Experimental Biology SB RAS, Kalugina O. V. ,   Siberian Institute of Plant Physiology and Biochemistry SB RAS
Published: December 2023

The results of the comparison analysis of the pine (Pinus sylvestris L.) forest coenofloras of the Taishet and Bratsk districts of the Irkutsk region are presented in this study. The floristic diversity of the pine forest is relatively high due to a variety of environmental conditions. 178 species belonging to 129 genera and 47 families were found in the surveyed area. The systematic structure of coenofloras in two districts was similar: the leading families and genera are the same. Coenoflora of the Bratsk district forests contains 140 species, and the Taishet district –148 species. The active core of both coenofloras consists of Pinus sylvestris, Vaccinium vitis-idaea L. s. str., Rubus saxatilis L., Pteridium aqulinum (L.) Kuhn., Anemone reflexa Willd., Anthriscus sylvestris (L.) Hoffm., Calamagrostis langsdorffii (Link) Trin., Carex macroura Meinsh. s.l., Galium boreale L., Lathyrus humilis (Ser.) Sprengel, Lupinaster pentaphyllus Moench., Equisetum pratense Ehrh., Pyrola asarifolia Michaux, and others. These species have high persistence and occurrence. Thus, the originality of cenofloras is low. Their comparison did not reveal any specific cenotic complex of species that was absent in the other area. In general, the flora of coniferous forests in these districts is boreal (according to the climatic zoning) with semi-humid and semi-arid features. Holarctic, Circumpolar, Eurasian-American and Eurasian species largely contribute to the flora composition. Structural diversity is increased by North-Asian, East-Asian, Manchurian-Daurian, South-Siberian and Mongolian, Okhotian species. Even if steppe zone is located south of surveyed region, their most widespread indicator species are represented in dry pine forest. In the total list of coenofloras the species of the Scots pine dominated coniferous belt-zonal group dominate (51 % of the total number of species). The leading role of the mesophytic series of species revealed (90 % of the total number of species). The dominant life forms among herbaceous plants are groups of short- and long-rooted species (56 % of the total number of species). Based on the D.N. Tsyganov indicator scale, the similarity of growing conditions in terms of ecological factors and edaphic regimes was shown. At the current, the Irkutsk region is one of the most industrially developed and densely populated areas in East Siberia. Large territories undergo strong and sometimes irreversible anthropogenic changes in the soil and vegetation cover. All this led to the invasion of adventive species, especially in rural and urban zones. One species (Cypripedium calceolus) listed in the Red Book of the Russian Federation and four species (Chimaphila umbellate, Epipactis helleborine, Daphne mezereum, Menispermum dauricum) listed in the Red Book of the Irkutsk Region were found in the surveyed area.