Vegetation cover of the North of the Koryak Region (Kamchatsky Krai) and its geobotanical subdivision

Abstract

Northern Koryakia belongs to two different vegetation zones: Beringian forest–tundra zone and East-Siberian larch forest subzone of the Eurasian boreal (taiga) zone. The territory of Northern Koryakia was subdivided into 3 geobotanical provinces and 14 districts. Most peculiar, 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 creeping woodland. 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 150–300 m). The alpine vegetation belt (up to 400–450 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. Azonal habitats, such as wide river valleys, are occupied by flood-plain forests (Chosenia arbutifolia, Populus suaveolens, Salix udensis, and S. schwerinii). In the floodplains of rivers and streams, shrubby willow thickets are 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 bogs with 40–60 cm-thick peat layers, hillocky mires, and polygonal mires develop. Tussocky sedge-cottongrass mires developing in the intermountain depressions are characteristic to the Anadyr-Penzhina lowland. Typical components of them are Carex lugens, Eriohorum vaginatum, Betula exilis and other hyparctic dwarf-shrubs. In the western part of the Penzhina River Basin, larch (Larix cajanderi) open woodlands form the northern forest limit. In addition, there are groves of Japanese white birch (Betula platyphylla) in the river valleys.