The causes of soil and vegetation variability on the slope of the VI Vistula terrace in the area of the designed “Dybowo” nature reserve near Toruń

Abstract

The aim of the present paper is to elucidate the variability of soils and vegetation in the designed nature reserve “Dybowo” near Toruń. The studied area is a slope of north-east aspect where ordered horizontal and vertical variability of soils and vegetation was found. Horizontal variability of soils is mainly caused by deluvial processes and vertical variability by type of parent material. A close relationship between the variability of soils and plant communities was found. The occurrence of Tilio cordatae-Carpinetum betuli association on a sandy slope of the Vistula VI terrace near Dybowo is possible due to the increase in habitat value of the soils occurring there. The factors resulting in this increase are: 1 – a thick cover of deluvia (sometimes exceeding 100 cm) enriched with humus, developed on almost all the area of the slope under investigation; 2 – the north-east aspect of the slope and direct vicinity of a large water body (river) resulting in better humidity conditions. Parent material of the soils is the factor differentiating vegetation of the designed “Dybowo” reserve at sub-association level. Tilio-Carpinetum corydaletosum sub-association demanding good site conditions developed in the slope area, where loamy material admixture occurs in the substratum.