engleski

Periphyton on different substrates in tufa depositing system

Tufa barriers have a variety of substrata, thus creating heterogeneous habitats for periphyton. We investigated the effect of three substrate types on periphyton diversity at Skradinski buk tufa barrier (Krka National Park). Samples of periphyton were taken from tufa substrate and leaf litter within experimental reach of the barrier experiencing modifications in hydrology due to the invasive species (Ailanthus altissima (Mill.) Swinge) removal. The dominant leaf litter species belonged to hornbeam (Ostrya carpinifolia). Periphyton was also sampled using artificial substrate (i.e., glass slides), placed on the same barrier, but within reach having permanent flow. Highest quantities of calcium carbonate precipitates were found on tufa substrates, while the calcite content on leaf litter and artificial substrates was lower. At tufa and leaf litter substrates periphyton sub- sampling was done by resuspension, while artificial substrate allowed direct examination. Determinations were done on live material, and showed ciliate dominance. The periphyton on the leaf litter comprised 49 taxa, while tufa substrate supported 22 taxa. Artificial substrate sustained different and the most diverse community, containing 64 taxa. Cluster analysis showed a clear separation of communities between the three substrates. Vagile periphytic taxa dominated on tufa substrate and leaf litter, while sessile taxa of suctorians and peritrichs had highest share in artificial substrate periphyton. Sampling technique can partly explain this difference, as artificial substrate analysis is the least destructive. Obtained results show high heterogeneity of periphyton within the same tufa barrier. Further research should address the periphyton diversity on artificial substrate within experimental reach.

Krka National Park, leaf litter, tufa, artificial substrate, protozoa

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