engleski

Periphyton in different microhabitats on tufa barrier in National Park Plitvice Lakes

Tufa, freshwater carbonate deposit, develops under specific physicochemical conditions. In Plitvice Lakes tufa creates barriers between succeeding lakes. On a microscale, tufa formation increases the habitat complexity, supporting heterogeneous periphytic communities. With the aim to test the differences in community composition of periphyton in different microhabitats, we performed in situ experiment using artificial substrates (glass slides) between May and November 2010. Four microhabitats on the barrier between last two lakes in the hydro-system differed with respect to current velocity and vertical position. Tufa deposition was more intense on upside microhabitats compared to underside. Ciliates dominated among heterotrophs with the share in abundance between 64% and 76%. Among 133 determined species, 73 were ciliates. Endemic species of heterotrichids Lagotia dinaridica was determined. Periphyton on the underside had on the average 16 times lower abundance and 8 times lower taxa number, compared to the upside communities on the same current velocity, probably due to deprived food resources. Microhabitat conditions structured ciliate communities, for instance Peritrichia and Hypotrichia were significantly more abundant in slow current. Our results highlight the heterogeneity of periphyton with tufa deposition possibly even increasing habitat complexity. Sampling designs for periphyton in such habitats should consider possible high within-habitat variability.

microhabitats; ciliates; current velocity; artificial substrate

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