Natural and anthropogenic fragmentation of the birches in the forest-steppe zone of the Altai territory
G.G. Sokolova, I.D. Borodulina
The article considers the results of the study of birch forests of forest-steppe zone of the Altai territory. The tendencies of anthropogenic changes in the species composition of birch forests are revealed. The process of fragmentation of birch pegs is analyzed, 3 levels of degradation are described. The synanthropization of birch forests occurs, accompanied by a decrease in their species and phytocenotic diversity. The consequences of synanthropization are the following: the fragmentation of plant populations and their isolation, the replacement of native plant communities by derivative and synanthropic, endemic and stenotopic plants by cosmopolitan and eurytopic ones, and the replacement of autochthonous elements by allochthonous ones. Universal impoverishment and unification of the species composition is accompanied by a decrease in productivity and resistance to external factors. Synanthropization causes leveling of zonal and regional differences of birch forests. As the anthropogenic load increases, the level of biodiversity decreases sharply, and during degradation, there is a transition to the dominance of species that are resistant to the changing ecotope conditions. Monocenoses – homogeneous forest communities consisting only of forest species – are extremely rare in the study area. They are characterized by a high association between the stand and the stand, the homogeneity of the structure and the conjugation with the ecotope. These are reference sites with a complete absence of anthropogenic transformation. Most forest ecosystems are a subject to varying degrees of human pressure.