Сибирский лесной журнал (Dec 2022)
Species composition and vegetation structure of light coniferous forests under pollution of aluminum smelter emissions in Irkutsk Oblast
Abstract
The species diversity and state of the ground cover of light coniferous forests in the territories of Irkutsk Oblast, polluted by emissions from three aluminum smelters (Bratsk (BrAZ), Irkutsk (IrkAZ) and Tayshet (TAZ)), differing in production technology and duration of impact on forests, were studied. 188 species of vascular plants from 49 families, 102 species of lichens, including 26 species of epigeal and 13 species of ground mosses were identified. Most species belong to the forest floral complex, mainly to the light coniferous zone-zonal group. Perennial herbaceous plants dominate in the biomorphological spectrum: its basis consist of long-rooted (30 % of the total flora), short-(26 %), and rod-rooted (13 %) species. The mesophytic species dominate in ecological spectrum. The most significant transformation of the species composition was observed in forest communities located in the industrial zone (within a radius of 0.5 km) of BrAZ, where the critical level of contamination of Scotch pine (Pinus sylvestris L.) trees was found, the drying of trees and the degradation of the grass-shrub layer contributed to the formation of solid moss cushion from silvergreen bryum moss (Bryum argenteum Hedw.) on the soil. In the industrial zone of TAZ and IrkAZ, where average and strong level of tree-stands contamination, respectively, was found we observed the increase of plant projective coverage to 70–85 % and the total number of vascular plant species due to the appearance of meadow, forest-steppe and ruderal, the composition of phytocenoses often changes towards the predominance of photophilic species. With a low level of contamination of tree-stands, changes in the floral complex are less pronounced and statistically insignificant compared to background territories.
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