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The highly specialized flora of localities affected by former metal ore mining and metallurgy is endangered by succession or intentional afforestation all over Europe. Its last remnants therefore deserve our attention. We examined whether Scots pine encroaching on a heavy-metal grassland (Olkusz Zn-Pb mining area, S Poland) is outcompeting specialized herbaceous species, as has been observed elsewhere. Plant species composition and richness sampled at 124 plots were analysed in relation to pine stand parameters (canopy cover, stand age, stand basal area), abiotic environmental factors (e.g. soil properties) and spatial variables (e.g. plot coordinates). Plots were divided into three shading categories and compared in terms of vegetation and habitat parameters. Scots pine outcompeted several light-demanding species, leading to a decrease of total species richness and cover. Characteristic species of this grassland ( Biscutella laevigata, Silene vulgaris) and some metal-tolerant plants were clearly insensitive to shading. For these early successional species, more important was the availability of microsites with shallow skeletal soil or bare subsoil. Tree stand parameters differently affected grassland vegetation: canopy cover caused primarily a compositional shift in the community, while stand age was the principal agent of decline in species richness. Scots pine increased the soil concentrations of available Ca and Mg, and negatively affected soil development (organic matter and mineral particle accumulation), which might be beneficial to some shade-tolerant grassland species. Maintaining the studied grassland's present species richness and composition would require cutting woody plants less frequently than recommended for dry grasslands of non-metalliferous sites, and disturbing the soil surface. [ABSTRACT FROM AUTHOR]

Campo rupestre is a kind of Brazilian rocky outcrop with high biodiversity and many endemic and threatened species. It occurs mainly in the Espinhaço Range in a contact region between Cerrado and/or Caatinga and Atlantic Forest. The Espinhaço Range is recognized as a region with the highest floristic diversity in South America and with many endemic species, most of which are associated with rocky outcrop environments. These, among other peculiarities, recently granted the Espinhaço Range the status of Biosphere Reserve. The relationship between soil and vegetation was studied in campo rupestre areas with quartzite and itabirite rocks. Three habitats in both lithologies were defined by geomorphology as: 1. Slopes with grasslands; 2. Plateaus with grasslands and 3. Valleys with woody savannas. In each lithology, 30 plots (10 × 10 m), 10 in each habitat, were defined. The species and their respective coverage were recorded and soil was sampled to perform chemical and physical analyses. The analyzed soils were similar in being sandy, acidic and with low fertility. Nevertheless, they exhibited differences in chemical and physical properties. Altogether there were 272 species, belonging to 70 families. The canonical correspondence analysis of soil variables and species coverage showed a clear segregation of lithological sites due mainly to the exchangeable content of Ca, Cu, Mg, Mn and S; soil particle size - central tendency and sorting; and the percentage of silt, fine soil and bare rocks. A strong correlation between plant species coverage and soil properties was also found. [ABSTRACT FROM AUTHOR]