Udział traw w zbiorowiskach roślinnych wykształcających się na obszarze wybranych kamieniołomów Wyżyny Śląskiej

The aim of the research conducted in dolomite quarries in the Tarnowicki Plateau (Silesian Uplands) was: to show the share of grasses in the fl oristic lists and their structural role in examined phytocoenoses; to compare plant communities of the study objects with those recorded on other industrial wastelands; to fi nd those grass species, which enabled to distinguished lower units among plant communities. In 15 recorded plant communities occurred from 0 (Potametum natantis) to 13 grass species (ruderal phytocoenoses of the Onopordion acanthii alliance and shrub community). The share of grasses in the fl oristic lists reached generally less than 15%. The lowest share in the plant cover (less than 6%) had grasses mainly in the communities of the Phragmitetea class, more than 10% in communities of the Artemisietea vulgaris class and shrub community and the highest in those communities, where grasses were dominants or co-dominants in patches or had higher frequency and cover in some lower units (variants) e.g.: Alopecurus aequalis. Calamagrostis epigejos, Arrhenatherum elatius, Phragmites australis, Poa compressa and P. palustris commonly occurred in analysed plant communities.