Dynamics of plant cover of meadow steppes after the cessation of traditional management in Opillia

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