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Flora and fauna of the Siberian forest
The most important factor influencing plants and wildlife distribution is climate. At the northern limit of tree distribution in the forest tundra of Siberia the mean annual soil temperature is -1 to -3°C. Around a hundred days a year have air temperatures above +5°C, and only 57–70 days are above +10°C. At the northern limit of distribution, trees grow in scattered groves on gentle southern slopes. Such forests grow on poor shallow soils that are low in humus, producing low-density forests. In the western Siberia such forests are composed of four tree species: Scotch pine (Pinus silvestris L.), Siberian spruce (Picea sibirica Ledeb.), Siberian [cedar] pine (Pinus sibirica Du Tour), and Siberian larch (Larix sibirica Led.). In eastern Siberia and the Russian Far East there is Daurian larch (Larix dahurica Led.). Among deciduous trees a few species of birch (Betula spp.) and aspen (Populus tremula L.) are common. Few rare plant species are found in the north of western Siberia (only one is listed in the Red Data Book – arctic paintbrush (Castilleja arctica Krey et. Serg.)). Up to 80 per cent of all forests are old-growth. As we move southward, the stands become denser and taller. The productivity also goes up. The forest composition remains essentially the same. The southern part of the northern taiga subzone is dominated by Scotch pine in Western Siberia, Siberian larch in Central Siberia, and mostly Daurian larch in Eastern Siberia.
The middle taiga typically has forests of spruce, Siberian pine and fir interspersed with secondary groves of birch and aspen. Pine forests are found in wetlands. The southern taiga has very diverse forests. They are more productive (up to 500 m3 per ha), and their composition is more diverse. Another aspect of the southern taiga is a lower proportion of wetlands. Soils in the area are fertile, well suited for agricultural production on cleared sites. Forest steppe is a separate natural zone. Some of it was artificially created by humans. Forest groves in this zone alternate with hay meadows and pastures, as well as with crops. In some cases, the productivity of such forest islands remains quite high (500 m3 per ha and more), usually these are Scotch pine forests. In other cases, due to increased aridity, productivity somewhat declines. Plant diversity here equals that of the southern taiga.
Most rare species are found among the best studied groups of animals, such as mammals and birds. Birds have the most species among the vertebrates. Avifauna increases from 145–160 species in forest tundra to 215–224 species in southern taiga.
Andrey Laletin
