A complex description of Siberian stone pine forests biodiversity at the southern border of their outreach in West Siberia (Russia)

The specificity of biological diversity in west Siberian subtaiga stone pine forest outliers in the forest-steppe adjacent area (Bazoisky forest area, Tomsk oblast, Russian Federation) and their current state was generally formed due to natural conditions of the region combined with uncontrolled forest forming process and destructive factors impact, including anthropogenic stresses, on the local ecosystem. These factors are closely linked and contribute to the nature of biodiversity and its composition development interdependently. Biological diversity of stone pine forests near southern border of their distribution features a number of distinctions in its structure. As compared to the stone pine forests in the north, these distinctions are as follows: a decrease in floristic composition of the tree layer, dominance structure transition to monospecies stands, a decrease in undergrowth species number, rich floristic diversity of plant communities, floristic composition degradation and low xylophagous insects population number. Functional biodiversity suffers from low vitality of Siberian stone pine that manifests itself at different ontogeny stages. This results from the forest stands old-growth, mechanical damage caused by nut collection, high distribution rate of rot pathogens, recurrent conifer-chewing pest outbreaks, livestock grazing and waterlogging. The vegetation cover foundation in this area is formed by a few variants of variiherbetum types of forest growing in automorphic habitats with distinct abundance of Rubus saxatilis, Carex macroura, Calamagrostis obtusata, Pteridium aquilinum, Padus avium and Sorbus sibirica. As their habitats grow more humid they are being crowded out by ferns (Matteuccia struthiopteris) followed by horsetail communities (Equisetum pratense). Swampy stone pine forests of Bazoi stow are basically pure herbae palustres communities. Species richness in these communities varies from 50 to 83 per 625 m area. Together with the predominant Pinus sibirica, Siberian spruce (Picea obovata) and Silver birch (Betula pendula) are considered as forest forming species of Bazoisky forest area. The age of trees in even- and uneven-aged forest stands varies with its average of 90 to 250 years. Mixed uneven-aged stone pine/spruce forest stands show better vital stability as compared to pure stone pine stands damaged by Siberian moth and only stone pine and spruce contribute to natural reforestation under parent stone pine stand canopy. The number of young trees total does not exceed 1.5 thousand per hectare. Their vitality is not high enough which makes the initial forest restoration difficult. The most frequent xylotrophic macromycetes are saprotroph Trichaptum abietinum and parasitic funges Phaeolus schweinitzii. 22 species of xylophagous beetles were found on coniferous trees which is almost 2 times less in comparison with the stone pine forest stands in south taiga.

Keywords

Authors

References