Diatoms (Bacillariophyta) from the Genus Eunotia and Pinnularia Developing on Soils in the Open Landscape of the Low Beskids

In the areas of medium mountains, including the landscape of the Low Beskids, turf communities guarantee the biodiversity increasing the value of open landscape and protecting soil from erosion. The aim of this study was to show the diversity of the diatom communities from the Eunotia and Pinnularia genera developing on soils under the conditions of varied landscape use (meadows, pastures. fallow lands). The research was carried out within the catchment area of the Ryjak stream in the Magura National Park, together with the buffer zone at three sites. The water content varied in the studied soils with fluctuating moisture content depending on the season and the research year. On the other hand, the pH values indicated high acidification of the studied soils. The diatomaceous analysis showed numerous occurrences of the Eunotia (12 taxa) and Pinnularia (18 taxa) genera. The acid pH of the soil undoubtedly favored the development of diatoms of these genera. Most species of the Eunotia and Pinnularia genera usually developed individually, except for Pinnularia borealis Ehrenberg and P. obscura Krasske. They are typically soil species; therefore, they often dominated in the material and occurred in most of the research seasons. Apart from cosmopolitan diatoms, rare or endangered taxa from the Red List of the algae in Poland (Siemiriska et al. 2006) were also found on soils. Four species belonged to the endangered category (E): Eunotia botuliformis F. Wild, Norpel & Lange-Bert., Pinnularia nodosa (Ehrenberg) Smith, P. schoenfelderi and P. viridiformis Krammer. Canonical analysis (CCA) demonstrated a rather low statistical significance of the impact of environmental parameters (pH and humidity) on the differentiation of diatom communities. It only confirmed the fact that diatoms develop better in the environment with permanent or at least periodic moisture, compared to the dry habitats.