Abstract
The article discusses the biodiversity dynamics of the components of secondary plant communities grown after winter clear cutting in the series of restoration of blueberry spruce forests in the bioclimatic conditions of the middle taiga subzone. For every succession stage (1(2)-year-old, 17(18)-year-old and 49(50)-year-old secondary communities and primary forest), about 20 descriptions (81 in total) were done. The authors separately describe the plant communities of forests swaths, skidding trails in cutting strip and main skid roads. On the basis of the obtained results, we determined species richness and biodiversity indices separately for tree, shrub, herb-dwarf shrubby, and moss layers. Industrial logging has been found to have an extremely negative impact on the species richness of forest species which absolutely disappear (especially stenobionts), decrease in abundance and constancy. In secondary communities on the territory of forest swaths and skidding trails, we fixed a decrease in biodiversity in the tree, shrub and moss layers and an increase in the herb-dwarf shrubby layer due to invasion of meadow, edge, and peatland species against a decrease in the abundance of species normally dominating in forest ecosystems. At heavily disturbed areas of the cutting area (main trails), secondary communities increase in both the total species richness and biodiversity at any layer except for the woody layer. The recorded increase in values happens due to formation of communities of very active species from different ecologic and cenotic groups. The floristic composition of the disturbed forest phytocenosis does not recover in fifty years after the anthropogenic impact.