Effects of contrasting land use on free-swimming rotifer communities of streams in Masurian Lake District, Poland

Abstract

The influence of land-use patterns on rotifer communities of streams in Masurian Lake District, Poland, was examined. Four streams in a forest-marsh area, two in forest-meadows, and two streams in agricultural areas were sampled monthly from March 1995 to October 1996. In all 41 genera and 139 species (i.e. ca. 30% of all rotifer species reported in Poland) were collected and identified, four of these are new to Poland. Rotifer numbers in the forest-marsh streams were 2 times higher than in forest-meadow streams and 10 times higher than in the agricultural streams. The forest streams also had higher numbers of species, both in the total number recorded in particular streams (74 in forest-marsh, 53 in forest-meadow, and 27 in agricultural ones), as well as the mean number of species recorded in one sample (17, 11, and 5 species, respectively). The values of Shannon's diversity index were markedly higher in the forest-marsh and forest-meadow (2.42 and 2.49, respectively) streams than streams from agricultural areas (1.49). The streams differed also in their dominant species. The forest-marsh stations were dominated by planktonic rotifers, whereas littoral-planktonic species dominated in streams in the forest-meadow area, and littoral species were most abundant in agricultural areas.