The aim of the study was to show the impact of the peat extraction on the development and properties of organic soils and plant habitat in post-extraction sites. The study was conducted in the complex of the Trzciñskie Mokrad³a Peatlands (Sudetes Mts., SW Poland). The Trzciñskie Mokrad³a Peatlands began to form in Preboreal (10960-9330 ±50BP) so that they are one of the oldest peatlands in the Sudetes. We analyzed 8 soil profiles (42 samples). Peat forming process there is still active in the moderate or strong degree (PtII-PtIII). The floristic composition of the studied areas was typical of transition peatlands. Successive dry and moist periods were observed in the developed of organic soils. The time gaps in peat profiles covering hundreds of years prove their extraction in the past.

Drainage and peat extraction may have a negative impact on existing hydrological conditions and, consequently, on the conditions of wetland ecosystems. The aim of this study was to assess human impact on the studied Trzcińskie Mokradła Peatland by comparing the concentrations and trace element (Pb, Zn, Cu, Cr and Ni) pools in the study area (extracted vs. non-extracted areas of peatland). The concentration of trace elements in organic soils and their pools were analysed in relation to their depth in the soil profiles, content of organic matter, soil pH values and the degree of decomposition of organic materials (peat, mursh). Fifteen soil profiles (90 samples) were examined. The total soil elements content was determined after digestion in a mixture of HCl+HNO3. The element pools were calculated and expressed in g m−2 of soil in 0–30 cm and 30–50 cm layers. Soils showed acidic or slightly acidic reactions. The high concentrations of Pb and Zn were mainly observed in the upper horizons. The deeper layers enriched with mineral fractions were also enriched in metals like Cr and Ni.