The birds of Pasvik / E. I. Khlebosolov, O. A. Makarova, O. A. Khlebosolova [et al. ; English transl. Nikita Chernetsov]. - Ryazan : Golosgubernii, 2007. - 175 с. : ил., портр.

E.l. Khlebosolov In the upper parts of slopes birch woods are replaced by crooked birch forest. covered with mature primaeval pine forest. Here the largest patch of spruce is situ­ ated with at least 300 trees. Mixed pine and birch forests grow on relatively rich soils in the lowlands or in the lower part o f the slopes under good inundation conditions (Fig. 2.1.D). In mixed forests the trees grow rather densely and have well developed crowns (Tsvetkov & Semenov 1985). These are the most productive forest habitats for birds. Generally forest ecosystems have the most diverse avifauna. Specific composi­ tion o f vegetation, age and condition o f the trees to a large extent govern the num ­ bers, spatial distribution, behavioural adaptations, and other biological character­ istics o f forest-dwelling birds. In the Pasvik valley raised bogs are common, mainly hummock-ridge peat bogs, subshrub peat bogs and sedge peat bogs (Fig. 2.1.E). Hummock-ridge bogs have a pronounced microrelief. In the ridges sedge and sedge sphagnum comm uni­ ties develop. The hummocks mainly consist o f sphagnum (Sphagnum fuscus). Here cotton grass, crowberry, bog bilberry, bog rosemary, bilberry brow. Subshrub peat bogs with hummocks are not uncommon. Hummocks are formed by peat moss with green moss admixed. On the hummocks, subshrubs, sedge, cotton grass grow. Low sedge and peat bogs develop at the sites with excessive inundation by mineralised water. The leading role in the formation o f vegetation communities is played by sedge and sphagnum moss. Along the concealed streams willow stands often devel­ op in lowland bogs (Kostina 1995). Wetlands are a habitat occupied by waterfowl, shorebirds, gulls and some passerines. 75