engleski

Distribution of the Dinaric cave-dwelling tube worm Marifugia cavatica Absolon & Hrabe, 1930 in Croatia

The tube worm Marifugia cavatica Absolon & Hrabe, 1930 is an endemic species of the Dinaric Karst and the only known stygobiotic serpulid. Recently, due to the development of cave diving techniques and the intensification of cave biology research, many new localities of this species were discovered in Croatia. M. cavatica is recorded in 71 localities in Croatia. Seven localities are known only from the literature and have not been confirmed by field research, and 11 sites contain only fragments of tubes flushed out of subterranean habitats. Except for the K2 cavern on the Island of Brač, all of these localities are on the mainland. Most of the localities (57.7%) belong to the Adriatic Sea Basin. Systematic research of the biology and ecology of M. cavatica in Croatia have never been carried out. It is known that Marifugia tolerates a range of water temperatures varying between 4°C (Lukina jama -Trojama Cave System) and 19°C (Jama u Predolcu, Pukotina u tunelu polje Jezero – Peračko blato). Marifugia can withstand prolonged periods outside the water but was never recorded in brackish conditions, although research of anchialine and other caves close to the Adriatic coast has been quite intense in recent years. The largest aggregations of M. cavatica were recorded in Pukotina u tunelu polje Jezero – Peračko Blato and Crni vir caves. Both of these caves are situated in the Jezero Karst Polje near Vrgorac, South Dalmatia, suggesting that the conditions there are very favorable for Marifugia. M. cavatica is the most widespread sessile species in groundwater of the Dinaric Karst. It is interesting that it inhabits all localities where other subterranean sessile species, the bivalve Congeria kusceri Bole, 1962 and sponge Eunapius subterraneus Sket & Velikonja, 1984, have also been recorded. M. cavatica is strictly protected by Croatian law, and its aggregations are enlisted as a unique habitat in National Habitat Classification (H 1.2.1.2.). Due to the insufficiency of information, M. cavatica was assessed as Data Deficient (DD) according to IUCN criteria in the Red book of Croatian cave dwelling fauna. As a sessile species it is directly threatened by changes in water regimes due to different hydrotechnical interventions as well as by different types of pollution of subterranean waters.

cave dwelling; tube worm; endemic species; Dinaric karst

nije evidentirano