Diatom species diversity and their ecological patterns on different substrates in two karstic streams in the Slovak karst
Journal of caves and karst studies
Many karstic streams are threatened both by anthropogenic and climate changes, but little is known about their algal biodiversity and conservation value, especially in the Slovak Karst. Diatom assemblages occurring on seven substrates, including stones, mud, submerged mosses and filamentous algae: Cladophora glomerata, Vaucheria sp., Ulothrix zonata, Spirogyra sp. in two nameless karstic streams in the Krásnohorská Dlhá Lúka Village and the Gombasek Cottage Settlement (the Slavec Village) in
... Košice Region of central-eastern Slovakia (the Silická Plateau) were studied. A total of 124 diatom taxa were found at four sites, where epilithic and epiphytic diatom assemblages dominated. Both species' richness and Shannon-Wiener indices showed congruent biotic integrity. The dominant taxa were alkaliphilous, halophobous-oligohalobous, requiring xeno-oligosaprobic and oligotrophic waters. Diatoms include: Diploneis krammeri, Encyonema ventricosum, Gomphonema acuminatum, Gyrosigma attenuatum, Navicula tripunctata, and Paraplaconeis cracoviensis. The latter species is a new report for Slovakia, reflecting the calcareous, geological nature of the Silická Plateau (the Slovak Karst). Diatom assemblages in two karstic streams consisted mainly of small-celled species of Achnanthidium, Amphora, Caloneis, Planothidium, and Stauroneis. Our results showed that the diatom assemblages were mostly structured by environmental factors of calcium and pH gradients, confirmed by canonical variates analysis (CVA) and Monte Carlo permutation tests. However, unique spatial and biological gradients, specific to different guilds related to each other, were also evident. The Slovak karstic streams should be especially protected and regularly monitored.