Changes in Composition of Mollusks within Corallina officinalis Turfs in South Istria, Adriatic Sea, as a Response to Anthropogenic Impact

Abstract

A very common intertidal alga, Corallina officinalis, serves as a refuge for numerous invertebrates within its settlements. The composition and structure of invertebrates may differ in relation to different natural or human-induced stress, and this study examined the effects of anthropogenic impact on the abundance and diversity of mollusks residing within C. officinalis settlements. Sampling was conducted during two seasons (Season 1 = algae’s maximum vegetation growth and Season 2 = algae’s minimum vegetation growth). Gastropods and bivalves made up 50% of all invertebrates identified, with a total of 47 species of gastropods, 25 species of bivalves, and one polyplacophoran species recorded. Considering the overall count of individuals, 4562 gastropods, 21,738 bivalves, and 260 polyplacophorans were collected from all available Corallina samples. The results indicated that locations under human impact showed a reduced number of the most abundant gastropod and bivalve species and a reduced average number of individuals.