Krka river (Croatia): Case study of bryozoan settlement from source to estuary: Bryozoan Settlement in the Krka River

Abstract

Krka River, a river in Croatia’s karstic Dalmatia region, has a length of 72 km and is famous for its seven tufa waterfalls of a total drop of 242 m. The source of the Krka River is at the base of the Dinaric Mountains, 3.5 km northeast of Knin, and it flows into the Adriatic Sea at Šibenik. The length of the freshwater section is 49.5 km; the brackish part is 23.5 km. In September 2008, 25 samples sites located between N 44°02.521′, E 16°14.087′ and N 43°49.121′, E 15°56.074′ were investigated for bryozoan occurrence combined with recording of environmental parameters. The specific situation with tufa deposition as well as heavy algae growth hampers colony settlement on the substrata. The species list contains phylactolaemate (Cristatella mucedo, Fredericella sultana, Plumatella emarginata, P. fruticosa, P. fungosa, P. geimermassardi and P. repens) and gymnolaemate (Paludicella articulata and Conopeum seurati) taxa. P. repens was the most abundant bryozoan, followed by P. geimermassardi, and P. emarginata. C. seurati in the Krka River estuary represents the first record of this species along the eastern (Croatian) coast of the Adriatic Sea.