Changes in the vascular flora of a postflotation zinc–lead ore spoil heap of the “Orzeł Biały” mining and smelting works in Bytom (Silesian Upland) after 15 years

A study on vascular flora of a Zn–Pb ore spoil heap of the “Orzeł Biały” mining and smelting works in Bytom, Poland, was carried out in the 2017–2018 growing seasons. The aim of this study was to: (i) present the characteristics of current vascular flora that colonizes the Zn–Pb heap, (ii) describe its dynamic tendencies and directions of changes after 15 years, and (iii) identify species that can be useful for planting as a part of biological reclamation. Ninety-two mostly native species of vascular plants, belonging to 36 families and 77 genera, were found on the examined heap. In the spectrum of life forms, hemicryptophytes prevailed over therophytes and geophytes. The most numerous ecological groups were ruderal and meadow species. As regards life strategies, highly competitive species and taxa with mixed CSR strategies dominated. The basic mode of seed dispersal was anemochory. In terms of habitat preferences, species associated with moderately light, warm, fresh, neutral, and medium fertility soil dominated in the species composition of the studied flora. In 2017–2018 compared to the 2002 growing season, statistically significant differences were found in the origin, life forms, ecological groups, life strategies, mode of seed dispersal of species and their habitat preferences relative to light, temperature, pH, and productivity. Frequently recorded pseudometallophytes (Agrostis capillaris, Cardaminopsis arenosa, Daucus carota, Deschampsia caespitosa, Leontodon hispidus, Plantago lanceolata, Silene vulgaris, Rumex acetosa) can be used for planting as part of biological reclamation of the area.