Многолетняя динамика пожаров в южных степях Северного Прикаспия и Мугоджар

Abstract

The purpose of the study is to identify regional features of the formation and long-term dynamics of grass fires in the southern steppes. A vast expanse covering mainly the southern steppe landscapes of the small-scale Mugodzhara massif, the plains of the Northern Caspian and Turgai is accepted as the key territory. The presented results are based on the analysis of the formed database of geospatial data containing information about the time and spread of fires for 1986-2021. The source materials were satellite images of Landsat and MODIS (Terra and Aqua satellites). As an indirect indicator of the pyrological state of the steppes, long–term statistical data on the number of grazed cattle (cattle, sheep and goats, horses). A significant heterogeneity of the pyrologic conditions for the years under review was revealed, three phases were identified: low (1986–2000), high (2001– 2010) and medium (2011–2021) fire activity. A comparison of the data obtained with the results of similar studies conducted by the authors earlier on the northern steppes indicates a high degree of similarity in the long-term dynamics of wildfires. By identifying the closeness of connections, it was established that the observed changes in the nature of fire–hazardous situations are due to changes in the intensity of use of plant and land resources, mainly during the agricultural development of the region. The intensification of fires was the result of the spontaneous restoration of steppe vegetation on uncultivated arable and little-used pasture lands associated with a sharp reduction in the level of agricultural production in the countries of the former USSR. It took about 8 years to restore the previously degraded vegetation to a state capable of supporting the steady spread of fires. One of the factors of pyrogenicity is the floral composition of plant communities and the density of herbage. The deterioration of the pyrological situation in the southern steppes (as well as in other steppe subzones) has become a specific regional response to the changed conditions.