The flora and vegetation of an old solvay process tip in Jaworzno (Upper Silesia, Poland)

Abstract

This paper demonstrates the flora, plant communities and substrates of an old soivay process spoil tip in Upper Silesia, Poland. In an area of 15 000 m2 there are growing 136 vascular plant species. The flora is characterised by the preponderance of Asteraceae - species and long-lived perennial herbs, many of them coming from meadows and grasslands. Ninety-five percent of species are apophytes despite the anthropogenic origin of the site. A majority of species are associated with moderately dry, base-rich soils with low or moderate levels of nitrogen. The site is shown to be an important refuge for some protected species, montane species and other elements uncommon in the local flora. An analysis of a series of samples used a methodology based on the assessment of percentage cover of particular species and multivariate analysis based on TWINSPAN. Both suggested a relatively high overall similarity between the samples with minor variations associated with moister substrates. Elemental analysis and pH determinations of soil samples associated with the releves revealed a narrow range of pH and an absence of any strong concentrations of heavy metals. A redundancy analysis of the soil-plant relationships suggested that the strongest trend of differentiation was most closely associated with a phosphate gradient, and the next strongest was pH and possibly waterlogging. The most species-rich vegetation was associated with low phosphate and high pH levels. The results could be interpreted to suggest that processes of soil development and plant succession are slow but nevertheless perceptible, with implications for future loss of diversity. The vegetation constitutes an assemblage essentially of one type showing only weak relationships with described vegetation types such as Molinio-Arrhenatheretea meadow, Festuco- Brometea grassland and Caricetalia davallianae mire. The results also suggest that the vegetation of the site is of considerable value for nature conservation. The site should be protected and be the subject of further research.