The influence of abiotic factors on the growth of two vascular plant species (Saxifraga oppositifolia and Salix polaris) in the High Arctic

The aim of this paper is to comprehensively evaluate the abiotic factors that influence changes in the annual growth rates of selected species of tundra plants (Saxifraga oppositifolia L and Salbc polaris Wahlenb.). The study was conducted in the area of the Fuglebergsletta coastal plain, in the vicinity of the Polish Polar Station (Wedel Jarlsberg Land, SW Spitsbergen). Relationships between the studied phenomenon and basic environmental factors and climate indicators were evaluated. The spatial variation of land surface temperatures (LST) was determined, as were the effects of the physical and chemical properties of soils and the spring melting of snow cover on growth rates. It has been argued that the spatial and seasonal variability of annual growth is determined by the rate at which snow cover disappears and by soil moisture, which determines plants' access to water. Soil moisture depends on soil particle size distribution and weather; it is regulated by the supply of snowmelt water and rainfall as well as by the depth of the top layer of permafrost (thaw depth), which determines the level of groundwater during the growing season. The spatial characteristics of the process of the disappearance of seasonal snow cover are co-determined by the morphology of the substrate and the physical properties of the soil. An important but destructive role is played by thawing episodes, which are increasingly frequent in the winter season, 'rain-on-snow' events, and glaze ice. The values of correlation coefficients indicate a positive role for precipitation and negative influence of temperature. The higher the temperature (along with low precipitation), the lesser the extent of plant growth. The observed trend towards warming in polar areas does not inevitably lead to an increase in biomass production. An increase in temperature during the growing season does not necessarily promote plant growth, but rather indicates drought stress caused by the lowering of groundwater levels related to the increase in thaw depth.