Spatial dynamics of caddisfly (Trichoptera) communities of intermittent karstic rivers in the Mediterranean

Povremene tekućice su dinamični i složeni slatkovodni ekosustavi u kojima voda povremeno prestaje teći zbog čega dolazi do njihovog presušivanja. Karakteriziraju ih promjene u režimu protoka, koje uključuju lotičku i lentičku fazu te kopnenu fazu. Za rad su odabrane četiri povremene krške rijeke u Hrvatskoj: Krčić, Miljašić Jaruga, Guduča i Čikola, u kojima su analizirani sastav i struktura zajednice tulara (Trichoptera). Za to su tijekom terenskog istraživanja mjereni fizikalno-kemijski čimbenici i uzimani uzorci makrozoobentosa koji su izolirani i determinirani u laboratoriju pomoću dihotomskog ključa. Sastav i struktura zajednice tulara su analizirani statističkim testovima poput Kruskal-Wallis testa, kanoničke analize korespondencije (CCA) i neparametrijske analize multidimenzionalnog skaliranja (nMDS). Razlike u zajednici tulara duž istraživanih rijeka kao i među dijelovima toka nisu značajne, dok su značajne razlike u zajednici tulara između rijeka Krčića i Miljašić Jaruge te Krčića i Čikole. Također, razlika između zajednica tulara lotičke i lentičke faze je velika zbog pronađene samo jedne svojte na jednoj rijeci u lentičkoj fazi. Najveći utjecaj okolišnih čimbenika na zajednicu tulara imali su električna provodljivost, brzina strujanja vode, koncentracija kisika i koncentracija ortofosfata u vodi.Intermittent rivers are dynamic and complex freshwater ecosystems in which the water flow periodically stops which causes them to dry out. They are characterized by changes in the flow regime, which includes the lotic, lentic, and terrestrial phases. Four intermittent karst rivers in Croatia were selected for this study: the Krčić, Miljašić Jaruga, Guduča and Čikola rivers, in which the composition and structure of the Trichoptera communities were analyzed. During the field research, physcio-chemical water properties were measured and samples of macrozoobenthos were collected. Samples were sorted and caddisflies were identified in the laboratory using a dichotomous key. The composition and structure of the Trichoptera communities were analyzed using the statistical tests such as the Kruskal-Wallis H test, canonical correspondence analysis (CCA) and nonparametric multidimensional scaling analysis (nMDS). Differences in the Trichoptera communites along the studied rivers as well as among the river reaches were not significant, while there were significant differences in the Trichoptera communities between the Krčić and Miljašić Jaruga rivers as well as between the Krčić and Čikola rivers. As only one taxon was recorded at the lentic phase of one river, the difference between the lotic and lentic phase was obvious. Of the measured environmental parameters, conductivity in water, water velocity, oxygen concentration and orthophosphate concentration in water, had the highest influence on caddisfly communities