Wpływ poprzecznej zabudowy hydrotechnicznej na zgrupowania chruścików (Trichoptera) w dopływach Kamienicy Nawojowskiej (Beskid Sądecki)

Badaniem objęto zgrupowania larw chruścików (Trichoptera) w pobliżu poprzecznej zabudowy hydrotechnicznej na trzech lewobrzeżnych dopływach Kamienicy Nawojowskiej, w Beskidzie Sądeckim. Mała poprzeczna zabudowa hydrotechniczna (do 2 m wys.) wpływa na kształt niektórych czynników abiotycznych, co z kolei oddziałuje na zgrupowania chruścików w profilu podłużnym cieku. Nie powoduje to jednak wyraźnego zubożenia gatunkowego, lecz zmiany w strukturze taksonomicznej i liczebności poszczególnych taksonów czy gildii pokarmowych

The research focused on assemblages of caddisfly (Trichoptera) larvae in the proximity of transversal hydrotechnical constructions (river bars, steps, anti-debris barriers) in three left-bank tributaries of the Kamienica Nawojowska River in the Beskid Sądecki Mountains. Three research transects were designated on each stream: above the construction, directly below the construction and in the distance of about 20 m below the second transect. Samples were collected in the seasons of 2010 and 2011 with the use of methods recommended by AQEM/STAR. The researcher analyzed the results by relating them to particular study sites and types of transects, as well as by determining the structure of dominance and the factor of faunistic resemblance according to the formula developed by Jaccard. The research has shown that transverse hydrotechnical constructions do not lead to greater differences in assemblages of caddisflies in streams of the same catchment area. Other abiotic factors play probably a more important role in this area (e.g. the use of valleys’ slopes, the degree of shading, the concentration of nutrients). Small transverse hydrotechnical constructions (up to 2 m high) probably affect the structure of caddisfly assemblages in each research transects within the limits of a given stream. However, this does not lead to any great reduction in the number of species but can cause changes in the taxonomic structure as well as in the number of particular taxa and feeding guilds. The extent and spatial arrangement of changes are correlated with the size and number of constuctions