Dirk Van Damme, Mary Seddon, Prem Bahadur Budha, Arthur E. Bogan, Maxim V. Vinarski, Do Van Tu, Alberto Martínez-Ortí, Gustavo Darrigran, Mikhail O. Son, Martin Haase, Canella Radea, Jasna Lajtner, Sonia Barbosa dos Santos, Guido Pastorino, Mohamed Ghamizi, David Allen, Christian Albrecht, Daniel L. Graf, Ted von Proschwitz, Ben Collen, Will Darwall, Jay Cordeiro, Annabelle Cuttelod, Nadia I. Dewhurst-Richman, Claudine Gibson, Vincent Prié, Kevin S. Cummings, Caroline M. Pollock, Charles N. Lange, Ümit Kebapçi, Rina Ramírez, David C. Aldridge, Eike Neubert, Evelyn Moorkens, Neelavar Anantharam Aravind, Kathryn E. Perez, Paul D. Johnson, Thomas von Rintelen, Dwayne A. W. Lepitzki, Olivier Gargominy, Kevin M. Smith, Craig Hilton-Taylor, Sophie E.H. Ledger, Anna-Sofie Stensgaard, M. Ramos, Manuel Lopes-Lima, Monika Böhm, Rajko Slapnik, Zoltán Fehér, Cristhian Clavijo, Frank Köhler, Esmée Fairbairn Foundation, Rufford Foundation, and Russian Foundation for Basic Research
With the biodiversity crisis continuing unchecked, we need to establish levels and drivers of extinction risk, and reassessments over time, to effectively allocate conservation resources and track progress towards global conservation targets. Given that threat appears particularly high in freshwaters, we assessed the extinction risk of 1428 randomly selected freshwater molluscs using the IUCN Red List Categories and Criteria, as part of the Sampled Red List Index project. We show that close to one-third of species in our sample are estimated to be threatened with extinction, with highest levels of threat in the Nearctic, Palearctic and Australasia and among gastropods. Threat levels were higher in lotic than lentic systems. Pollution (chemical and physical) and the modification of natural systems (e.g. through damming and water abstraction) were the most frequently reported threats to freshwater molluscs, with some regional variation. Given that we found little spatial congruence between species richness patterns of freshwater molluscs and other freshwater taxa, apart from crayfish, new additional conservation priority areas emerged from our study. We discuss the implications of our findings for freshwater mollusc conservation, the adequacy of a sampled approach and important next steps to estimate trends in freshwater mollusc extinction risk over time., The authors would like to acknowledge the Esme ́e Fairbairn Foundation (NIDR and MB) and the Rufford Foundation (MB) for their generous support. MV is supported by the Russian Fund for Basic Research (project No. 19-04-00270).