Contemporary Dynamics in Vegetation of the Polar and Subpolar Regions of Western Siberia Using Remote Sensing Data

Abstract—Trends in the climatogenic dynamics of phytomass on the sites located along the borders of Western Siberia’s natural zones (the border of frozen and unfrozen bogs, the border of taiga and open boreal woodlands, and the northern boundary of the distribution of woody vegetation) were spotted based on the vegetation index NDVI derived using the sensors of the MODIS-Terra satellite for the period 2000–2020. The assessment of the vegetation dynamics and the factors that determine it was conducted with the use of the mean and maximum NDVI values and the relation of the index with basic climatic variables. A positive trend of NDVI caused by an increase in air temperature and precipitation was revealed in all the studied areas. The phytomass of open boreal larch woodlands grew the most strongly, and the greatest interannual variability was noted there. A correlation analysis conducted on the basis of the NDVI mean values displayed that improvements in vegetation growth conditions in tundra are mainly caused by the impact of the average summer temperature. The increase in phytomass in taiga is mostly connected with the presence of a tree stand that better retains snow cover, which contributes to less freezing of the ground during the cold season.