Extinction risk is linked to lifestyle in freshwater gastropods

AIM: Freshwater ecosystems and their biota are severely endangered by global change today, and predicted extinction levels are skyrocketing for many taxa. Most studies have focused on entire clades, while approaches testing for selective extinction risk with respect to ecological traits are rare. As studies are typically based on modern faunas, the generality of the detected patterns in the context of the current biodiversity crisis remains uncertain. We use a dataset of fossil and modern freshwater gastropods to investigate extinction probability in dependence of lifestyle and geographic distribution. LOCATION: Europe, Miocene to present‐day. METHODS: We performed generalized linear mixed modelling to test for a relationship between extinction probability and taxonomic group (Caenogastropoda vs. Hygrophila, reflecting different lifestyles) and range size, while using time as random effect. Extinction and survival of modern representatives was predicted based on IUCN conservation status. To identify the types of faunas with elevated extinction risk with respect to lifestyle, we tested for a relationship between the proportion of Caenogastropoda and lake surface area and geological duration using generalized linear models. RESULTS: We found a clear relationship between extinction likelihood and lifestyle, which is linked to differences in range sizes and is independent of geological time. Caenogastropoda are more prone to go extinct. A strong positive relationship between the proportion of Caenogastropoda and geological duration was found, showing that Caenogastropoda are more dominant in long‐lived lakes. MAIN CONCLUSIONS: The elevated extinction risk of caenogastropods is linked to their smaller geographic ranges, which reflects their comparably poor colonization ability, and urges enhanced conservation efforts. Their high diversity and high degree of endemism in long‐lived lakes render, especially these archives of evolution important conservators of biodiversity. As most of these lakes are under severe anthropogenic pressure, concerted conservation measures are needed to ensure the survival of their unique biota.