ASSESSMENT OF THE VEGETATION DYNAMICS OF REINDEER PASTURES IN THE YAMAL PENINSULA USING A SEMI-AUTOMATIC CLASSIFICATION METHOD OF SATELLITE IMAGES

Abstract

The research on current changes in the vegetation cover of reindeer pastures in the subzones of northern andsouthern tundra of the Yamal peninsula was carried out. The area of the sites disturbed by reindeer grazing from 2013 to 2022 wasidentified based on field and remote sensing data. Processing of Landsat-8 -9 images using the semi-automatic classification method made it possible to highlight the most common ecotopes with their inherent plant communities, including reindeer-damaged areas with disturbed plant communities and deflationary outcrops. It was revealed that due to the high concentration of reindeers in the southern regions of the Yamal peninsula, the area of the territory disturbed by intensive reindeer grazing is 7.7 times larger than in the subzone of northern subarctic tundra. The weather anomalies determine the character of seasonal reindeer migration and have an impact on the degree of the vegetation transformation caused by grazing. In 2014, the load on ecosystems in the southern tundra increased, and the best conditions for reindeer migration to the summer pastures in the northern tundra were in 2016. The herd expansion in the peninsula's south causes an expressed positive trend in the dynamics of areas degraded by reindeer grazing (2.1% per year) and practically its absence for the northern tundra. For the same reason, intensive grazing in the southern tundra significantly contributes to the increase in the area of sandy outcrops (r = 0.94). The growth trend of the NDVI values noted by many researchers in the tundra of Western Siberia, has not been noted by us in the subzone of the southern subarctic tundra. Here, reindeer grazing and a large area of disturbed tundra lead to a decrease in photosynthetically active phytomass.