What determines the mollusc diversity in the isolated karstic lakes of central Albania?

• Authors: LORENCOVÁ Erika
• Year of publication: 2021
• Type: Appeared in Conference without Proceedings
• Description: Lakes and ponds in the Mediterranean karstic areas represent unique refugia for many species of stagnant waters. Although these ecosystems have faced notable degradation and eutrophication during the last few decades, only little is known about their malacofauna and the possible effect of these negative changes on molluscs. Therefore, we quantitatively sampled mollusc assemblages at 40 standing water bodies within a compact karstic area of central Albania. Besides, we also measured 35 environmental variables that may affect the studied mollusc communities. In total, we found only nine species of widely distributed mollusc species, including three non-native ones. The sites hosted notably species-poor assemblages, ranging between 0 and 6 species, with almost a half of the studied sites being mollusc free. The presence of molluscs was positively affected by the amount of littoral vegetation, the reed cover, fine organic material, and high-water transparency. By using the regression tree method, 40% of the total variability of species richness was explained. The species richness was driven mainly by the reed cover and the length of the shoreline. Water transparency and lake surface area explained 12.4% of the total assemblage composition variance. Our results showed that limited development of different types of littoral vegetation, changes of the landscape management during the second half of the 20th century, and natural isolation of sites, can be concluded as the major drivers for mollusc species presence and distribution in the studied network of isolated karstic lakes.