Diversity of the malacofauna of the upper course of the Sava River

Abstract

Cilj rada bio je odrediti raznolikost i strukturu zajednice slatkovodnih mekušaca gornjeg toka rijeke Save. Terensko istraživanje provedeno je tijekom lipnja i rujna 2012. godine na 16 postaja raspoređenih duž gornjeg toka rijeke. Puževi su određeni do razine vrste, a školjkaši do razine roda. Tijekom istraživanja ukupno je pronađeno 14 vrsta puževa te jedan rod školjkaša. Najveći broj vrsta mekušaca, njih pet, zabilježen je na postaji S-Med. Najzastupljenije vrste puževa su Ancylus fluviatilis i Sadleriana fluminensis. Analiza uzrasne strukture pokazala je da su na istraživanim postajama prisutne i juvenilne jedinke mekušaca. Provedena analiza funkcionalnih hranidbenih skupina mekušaca pokazala je da na većini postaja najveći udio imaju strugači nakon kojih slijede detritivori, izuzev dvije najnizvodnije postaje, gdje najveći udio imaju aktivni filtratori. Najviše vrijednosti Shannonovog i Simpsonovog indeksa raznolikosti zabilježene su na postajama S-Lju i S-Pas, dok su najniže vrijednosti ovog indeksa zabilježene na postaji SD-Šob. Rezultati klaster analize pokazuju jasno izdvajanje zajednice puževa na postaji S-Vrh od zajednice puževa na ostalim istraživanim postajama. Zaključno, rezultati ovog rada predstavljaju značajan doprinos poznavanju malakofaune gornjeg toka rijeke Save i polazna su osnova za buduća istraživanja.The main objective of this study was to determine the diversity and community structure of freshwater molluscs of the upper course of the Sava river. Field research was conducted during June and September 2012 at 16 stations distributed along the upper course of the river. Snails are determined to species level and bivalves to genus level. During this study, a total of 14 snail species and one bivalve genus were found. The highest number of species, five, were recorded at station S-Med. The most common species of snails are Ancylus fluviatilis and Sadleriana fluminensis. Analysis of molluscs size classes showed that younger individuals are also present at investigated stations. Analysis of molluscs functional feeding guilds showed that dominated group is grazers followed by detritivors unless the last two stations were dominated gruop is active filtrators. Highest values of the Shannon and Simpson diversity indices were recorded at stations S-Lju and S-Pas, while the lowest values of the indices were determined at station SD-Šob. Results of the cluster analysis showed a clear separation of the snail communities at station S-Vrh and snail communities at other stations. Finally, results of this study represent a significant contribution to the knowledge of malacofauna of the upper course of the Sava River and will be a starting point for future research