VEGETATION COVER OF THE NORTH OF THE KORYAK REGION (KAMCHATSKY KRAI) AND ITS GEOBOTANICAL SUBDIVISION

Phytosociological data obtained in the Koryak District in 2011–2017 served for the subdivision of its vegetation cover. Most peculiar for the area, the Siberian dwarf pine (Pinus pumila) elfin woods occupy zonal mesic habitats of plains, plateaus and gentle mountain slopes. They form a zonal vegetation type of Beringian krummholz. The polar birch (Betula middendorffii) shrubs (up to 1.5 m tall) and dwarf-alder (Alnus fruticosa) thickets form another important vegetation type associated with Pinus pumila open woodlands. These two vegetation types form a distinctive subalpine vegetation belt at lower elevations (up to 150–250 m a. s. l.). The Alpine vegetation belt (up to 350–400 m) is characterized by a complex of dwarf-shrub and lichen-rich tundra communities that occur under conditions of a heat deficit and very short growing season. Azon al habitats, such as wide river valleys, are occupied by Chosenia arbutifolia, Populus suaveolens, Salix udensis and S. schwerinii flood-plain forests. In the floodplains of rivers and streams shrubby willow thickets widespread, predominated by Salix pulchra, S. alaxensis,S. krylovii and S. hastata. Several vegetation types, mainly coastal dwarf-shrub tundra, mires, salt marshes, mesic and hygric meadows, and isolated Betula ermanii groves are distributed on azonal sites. In waterlogged habitats of lowlands and depressions sedge-moss mires, Sphagnum-rich oligotrophic mires with 40–60 cm-thick peat layer, hillocky mires, and polygonal mires develop. Tussocky tundras, which develop in the intermountain depressions, are characteristic to the Anadyr-Penzhina lowland. As the typical component of them appear Carex lugens, Eriohorum vaginatum, Betulaexilis and other hyparctic dwarf-shrubs. In the western part of the Penzhina District larch (Larix cajanderi) open woodlands form the northern forest limit. In addition, there are groves of Japan birch (Betula platyphylla). Работа поддержана РФФИ, проект № 16-05-00736-а.