ИСТИНА

Biodiversity of arctic islands is highly vulnerable under anthropogenic pressure and climate change. Many arctic islands, being almost inaccessible, are hitherto poorly investigated, so that we even don’t know the scale of presumed changes and possible losses in biodiversity. Our study and analysis of the vegetation of Sosnovets Island is to contribute to the knowledge about arctic island ecosystems. Sosnovets Island (66°29' N, 40°41' Е) is located 8 km southward the Arctic Circle, near the southeast part of the Tersky Coast, in the funnel-shaped opening of the White Sea to the Barents Sea. The area of the Island is 40.6 ha and the shore height is 10–15 m above sea level. There is Sosnovets Lighthouse (in action since 1862) situated in the central part of the Island, and a meteorological station in the southern part. Sosnovets Island lies at the southern limit of tundra, and its placement to the tundra or the forest-tundra has been debated in various regional and circumpolar botanical and geographical schemes. In our work we consider the Sosnovets Island to belong to the southern tundra on the basis of its flora and vegetation. We used the Braun-Blanquet approach for vegetation description and classification. 76 relevés were collected in August 2016, with geo-positioning and habitat descriptions. All of them were included in the TURBOVEG database. Herbarium specimens were deposited in MW, H, PTZ, KAND, and KPABG. Dwarf-shrub (Empetrum hermaphroditum) and lichen (Cladonia arbuscula, Flavocetraria nivalis) communities of class Loiseleurio procumbentis–Vaccinietea Eggler ex Schubert 1960 are formed on sandy deposits and occupy only a limited area – 0.4 ha (1 % of the Island’s area). Vegetation of the permafrost peatland prevail on the major part of the Island. Cloudberry-crowberry-lichen and cloudberry-crowberry communities prevail on drained elevated sites of the peatland. They are similar to those described from vast peatlands of East European tundra in the alliance Rubo chamaemori–Dicranion elongati Lavrinenko et Lavrinenko 2015, class Oxycocco-Sphagnetea Br.-Bl. et Tx. ex Westhoff et al. 1946. Nevertheless, the absence of characteristic species of the class Oxycocco-Sphagnetea, namely Andromeda polifolia, Ledum palustre, Eriophorum vaginatum and Sphagnum spp., is a characteristic feature of Sosnovets Island. This feature distinguishes the peatland of Sosnovets Island from peatlands on the mainland of Malozemelskaya and Bolshezemelskaya Tundras and brings it together with those on islands of the Barents Sea (Vaygach, Kolguev, and Dolgiy) where these species are absent or rare as well (Lavrinenko, Lavrinenko 2015). The majority of cottongrass- and sedge-and-Sphagnous communities of the Island belong to the class Scheuchzerio palustris–Caricetea fuscae Tx. 1937. They occur in flarks and coastal extensions of dells draining the peatland. They are attributed to the suballiance Caricenion rariflorae Lavrinenko et al. 2016 of the alliance Sphagnion baltici Kustova in Lapshina 2010, due to the presence of characteristic species of these syntaxa: Sphagnum lindbergii, S. balticum, Polytrichum jensenii, Eriophorum scheuchzeri (Lavrinenko et al. 2016). Several sedge-Shagnum dominated communities of the peatland flarks lack the abovementioned species but include Straminergon stramineum, Warnstorfia exannulata, Epilobium palustre. They are analogous to communities of the alliance Drepanocladion exannulati Krajina 1933. The communities of the suballiance Caricenion rariflorae are widespread in the peatland flarks of the East European tundra, the communities of the north and high-altitude alliance Drepanocladion exannulati occur, although rarely, in flarks with flowing water (Lavrinenko et al. 2016). Coastal vegetation of the Island belongs to intra-zonal classes Juncetea maritimi Br.-Bl. in Br.-Bl. et al. 1952 (alliances Puccinellion phryganodis Hadač 1946, Caricion glareosae Nordh. 1954, Armerion maritimae Br.-Bl. et De Leeuw 1936) and Ammophiletea Br.-Bl. et Tx. ex Westhoff et al. 1946 (alliance Agropyro–Honckenyion peploidis Tx. in Br.-Bl. et Tx. 1952). The grass species Calamagrostis deschampsioides is a characteristic feature of these communities. It has more eastern distribution in Fennoscandia, and is very rare on the Kola Peninsula. The anthropogenic vegetation of Sosnovets Island is a result of the anthropogenic impact for more than 150 years and is quite diverse and extensive (5.0 ha, 12.3%). It takes the 2nd place on the Island, regarding its area, whereas the 1st place is taken by the vegetation of peatland. It is predominantly composed of alien meadow species (Deschampsia cespitosa, Lathyrus pratensis, Trifolium repens, Alchemilla subcrenata, Vicia cracca, Ranunculus acris). The invasive Deschampsia cespitosa occurs in the wet degraded flarks of the peatland and other species were found in moderately moist places. Thus, the vegetation of Sosnovets Island is typical of the tundra zone and Sea shore. At the same time, due to the combination of the natural conditions and the long-term anthropogenic impact, the vegetation of Sosnovets Island has a high specificity among the small-size Arctic islands. Keywords: vegetation; island vegetation; Braun-Blanquet classification; Murmansk Region. References: Chernov, Y.I. & Matveeva N.V. 1979: (Regularities of zonal distribution of communities on Taimyr.) — In: Alexandrova, V.D. & Matveeva, N.V. (eds.), (Arctic tundra and high arctic tundras (polar deserts) of Taimyr): 166–200. Science Publishers, Leningrad. (In Russian.) Lavrinenko, O.V. & Lavrinenko, I.A. 2015: (Communities of the class Oxycocco-Sphagnetea Br.-Bl. et R. Tx. 1943 in the East European tundras.) — Rastitelnost Rossii 26: 55–84. (In Russian with English summary.) Lavrinenko, O.V., Matveeva, N.V. & Lavrinenko, I.A. 2016: (Communities of the class Scheuchzerio-Caricetea nigrae (Nordh. 1936) Tx. 1937 in the East European tundras.) — Rastitelnost Rossii 28: 55–88. (In Russian with English summary.)