THE ECOLOGICAL CONDITIONS OF THE OCCURRENCE OF DROSERA ROTUNDIFOLIA IN MAN-MADE HABITATS.

Drosera rotundifolia (round-leaved sundew) is zoophagous plant of boreal type of range. It is a species confined to bogs. It is commonly believed that the plant grows in acid (pH 3.5-5.5), oligo- and dystrophic habitats, supplied mostly by precipitation, on peat soils with conductivity ranging 50-100 аS/cm. It is also reported from sand dunes. These studies conducted by authors in southern Poland demonstrated that ecological amplitude is much more wider than that described in literature body. The species occurs both in acid and slightly acid mires as in old unexploited sandpits where due to morphogenetic, geochemical and biological processes development of anthropogenic wetlands takes place. The studies included floristic inventories with estimation of cover using modified Braun-Blanquet scale in the plots of 16 m2 and analysis of environmental variables in vegetation patches with minimal cover of Drosera rotundifolia of 10%. The anthropogenic habitats with the occurrence of D. rotundifolia were compared with natural fragment of mires where this species occurs. In anthropogenic habitats D. rotundifolia occurs in patches with higher contribution of calciphilous species (Caricetalia davallianae order) or poorer-floristically phytocoenoses with Lycopodiella inundata. This floristic diversity is determined by habitat conditions i.e. pH, conductivity, cover of moss layer (CCA analysis). Anthropogenic biotopes are characterized by higher conductivity, even more than 500 аS/cm and more alkaline pH when compared to natural habitats [ABSTRACT FROM AUTHOR]