The diversity of diatom assemblages developed on fallow soil in Pogórska Wola near Tarnów (southern Poland)

The aim of this work was to investigate the species diversity of diatoms growing on fallow fields on loose sand. The study site was located in the western part of Pogórska Wola near Tarnów (southern Poland). Samples were collected from fallow land once a month from April to December 2011. 57 diatom taxa from 19 different genera were found. The most numerous genera were Fragilaria (8) and Luticola (7). The highest species richness was observed in December, November and July, while the highest values of species diversity (Shannon–Wiener index) were recorded between August and October. Four taxa – Pinnularia borealis Ehrenb. var. borealis, Stauroneis borrichii (Petersen) Lund, Hantzschia amphioxys (Ehrenb.) Grunow, and Luticola nivalis (Ehrenb.) D.G. Mann, were found to be the dominant species. Neutral species (a pH of about 7) dominated in all months (from April to December), reaching an over 90% share in the assemblage. In terms of nitrogen content, nitrogen-autotrophic taxa, tolerating an elevated concentration of organically bound nitrogen, occurred most abundantly, as was indicated by the low content of nitrogen in the soil