DEPENDENCE OF GRASS COVER TAXONOMIC AND ECOLOGICAL STRUCTURE ON THE ANTHROPOGENIC IMPACT IN FOREST ECOSYSTEMS

Pine forests Chigirinsky Bor grow on fresh sod-podzolic soils formed on ancient alluvial deposits. Pine forests are characterized by stringent moisture regimes and constantly suffer from lack of productive moisture in soil. Industrial development of Cherkasy in 60th years of ХХ century leaded air pollution and emissions of SO2, NOx, NH3, and dust. This contributed to significant negative influence on the surrounding forest ecosystems from enterprises of Cherkassy industrial agglomeration. The grass cover in pine stands of Chigirinsky Bor transforms into xerophytic grasses and ruderal communities under the impact of negative biotic and abiotic factors. They are namely the anthropogenic violation of forest conditions, stands decline, recreational and industrial tree crowns understocking, xerophytic and heliophytic transformations of forest conditions. All the above mentioned caused strong ruderal and adventive transformation of grass cover. We registered the changes in nitrophilous plant spread regards the Cherkasy industrial agglomeration approaching which emits toxic with nitrogen-containing gases. Adventive and other non-forest species displace ferns and mosses, the ratio of ecomorfs is also changes due to increase of the quantity and development activation of annuals, xerophytic, ruderal, and nitrofil plants. The Asteraceae/Brassicaceae 3:1 ratio indicates significant anthropogenic violations in the region. We fixed the xerophytic, ruderal, and adventive transformation of grass cover in forest ecosystems. It is also founded the tendency of expanding the fraction of mesophilic plant species due to alterations in water regime (creation of Kremenchug reservoir and draining of floodplain Tyasmyn). When approaching the Cherkasy industrial agglomeration the grass cover degradation is clearly observed on the environmental profile. All this causes the forest ecosystem degradation and gradual loss of forest vegetation typical characteristics. We revealed the domination of plant species that are tolerant to transformed forest conditions due to drastic anthropogenic changes of ecological regimes in Chygyryn's Bor. Key words: grass cover, Chigirin's Bor, anthropogenic impact, forest ecosystem, industrial transformation and degradation of grass cover