Home – Home – Jornals – Geography and Natural Resources 2022 number 3

A geobotanical, soil and biostratigraphic study of the small islands of the Eugenie Archipelago was carried out. An assessment of the current state of their ecosystems has been made. The main factors determining the composition, structure, diversity and dynamics of soil and vegetation cover in the Holocene were multidirectional climatic fluctuations associated with variations in insolation which led to a restructuring of the atmospheric circulation and sea waters, and to sea level fluctuations. It is found that in warm epochs, forest cover increased, and broad-leaved forests with a rich diversity of species were dominant, whereas in cold phases tree vegetation became more sparse, with birch and alder predominating in its composition, and the share of broad-leaved species was greatly reduced. The anthropogenic impact was manifested in the appearance of weeds, the passage of fires, and the development of erosion and turbidity of the soil cover. The modern vegetation cover of the studied small islands of the Eugenie Archipelago consists of anthropogenically altered low-growing broad-leaved shrub-forb forests with lianas, shrub-subshrub phytocenoses, halophytic vegetation of beaches and petrophytic vegetation of coastal rocks. The soil cover is represented by zonal soils: brown soils, mainly with a thin and strongly skeletal profile. It was found that the main differences between the vegetation cover of the small islands of the archipelago and that of the large ones are: the dominance of grass and shrub vegetation, in particular, thickets of Gmelin wormwood and low forests due to the constant influence of winds. At the same time, conditions are created for the active development of humus formation and illuvial-humus processes, which ensures the formation of a deeply humified soil profile. The small area of the islands and the flattened relief determine more seaward conditions, which is reflected in the composition of plant communities, in the distribution of halophytic groups in the overwash zone, shrub-subshrub communities with shrub linden in the windward areas. A protected species of Japanese yew occurs only singly on the less accessible of the Pakhtusov Islands. Due to a significant share of forest vegetation, the lichen cover is dominated by epiphytic lichens; there occur epilithic species typical for open ecotopes on rocky outcrops, and halophytic species in the overwash zone.