Gastropod assemblages in the harsh environment of Mediterranean Dinaric karst intermittent rivers

Freshwater snails inhabit a wide range of freshwater habitats, including the intermittent ones, specific adaptations enabling them to survive the dry phase for an extended period of time. Despite an increasing scientific interest in biota occurring in intermittent freshwater habitats, our knowledge about environmental factors shaping freshwater gastropod assemblages in such habitats is still poor. Therefore, this study aimed to assess gastropod assemblage composition in four karst intermittent rivers in the Mediterranean during the lotic phase, compare gastropod taxa richness and abundance among the rivers, and determine their relationships with environmental variables. A total of six taxa was recorded, with each river harbouring a unique, species-poor (up to three species) assemblage. Gastropod assemblages were influenced by the physico-chemical water properties, especially the concentration of dissolved oxygen in water, conductivity, and chemical oxygen demand. Our results provide a basis for further research on freshwater snail assemblages in the Mediterranean karst intermittent rivers, as the need to protect these vulnerable ecosystems and develop adequate monitoring practices becomes imperative due to climate change and anthropogenic pressures.