No abstract

Meadow steppes of Opillia (western edge of Podillia Upland, Western Ukraine) belong to xerothermic calcareous grasslands which are the most species-rich habitats in Europe. This paper contains results of a nine-year study (2010–2018 years) of plant species composition in ‘Ostrivets’ grassland after the cessation of traditional management (mowing). The patch had been burnt for at least five years running and then abandoned for five more years. The patch was chosen as a model grassland of abandoned meadow steppes. We examined plant species richness and composition on three sample plots of 5 x 5 m2. In 2010, at the beginning of annual burning practice the plots harboured 114 species. One year after cessation of disturbance by fire (2014), species richness decreased to 108 species. In 2018, after five years of abandonment it reached 83 species. Abundance of the dominant species (Brachypodium pinnatum) remained unchanged when the patch was under annual burning regime. After abandonment of the habitat Molinia arundinacea became the dominant species. Species composition experienced changed as well. Only 37.9% of species remained in the sample plots from 2010 till 2018. The proportion of meadow-steppe species halved, they were substituted by species of forests, forest edges and ruderal species. Percent of meadow species did not significantly change, however this group of species began to dominate within the community. The cover of woody vegetation reached 15–20% in 2018. Rubus caesius encroached on the grassland in 2014 and gained 20% of projective cover in 2018. Ten out of thirteen rare species disappeared from the habitat during the study period. ‘Ostrivets’ habitat requires urgent measures to be taken to restore and preserve meadow-steppe species composition. We suggest the following measures: elimination of trees and shrubs, regular moving and overseeding of extinct species.

The vegetation of a landfill of hexachlorobenzene toxic waste was studied. It is situated in the neighborhood of Kalush (Ivano-Frankivsk region) and has an area of 4.5 ha. As a result of damage to the containers, hazardous waste has contaminated the air, soil and aquifers at the test site and adjacent areas. During the period 2010–2012 measures were taken to recover and remove the mixture of toxic waste and contaminated soil from the landfill. In its place, unpolluted soil was brought to the landfill. Work was carried out to recultivate the territory. Nowadays natural succession of vegetation cover is observed. There is closed herbaceous cover in the western part of the landfill. The total projective herbaceous cover in the central and eastern parts varies from 10% to 60%. Vegetation composition of the landfill contains eight syntaxa of association rank that belong to seven alliances, six orders and five classes. Communities of the Phragmito-Magnocaricetea and Bolboschoenetea maritimi classes (ass. Typhetum laxmanii) grow in areas with excessive humidification. The central and eastern parts of the waste landfill are primarily occupied by halophytic communities of the Puccinellio distanti-Tripolietum vulgare association of the Asteretea tripolium class. Ruderal communities belong to three associations of the Artemisietea vulgaris class. These communities mainly occur in the periphery zone of Kalush landfill. Areas with a moderate moisture regime are occupied by ruderal communities of the Calamagrostietum epigeios association of the Agropyretea repentis class. The total number of vascular herbaceous plant species at the landfill is 119. The dominating groups are meadow, synanthropic and wetland species. The differentiation of vegetation cover is caused by heterogeneity of edaphic and hydrological conditions, also by different activity of succession processes.