Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other groups remain largely off the public and scientific radar. Freshwater mussels (Bivalvia, Unionida) are an alarming example of this conservation bias and here we point out six conceptual areas that need immediate and long-term attention: knowledge, threats, socioeconomics, conservation, governance and education. The proposed roadmap aims to advance research, policy and education by identifying the most pressing priorities for the short- and long-term conservation of freshwater mussels across Europe.

Cavanilles Institute of Biodiversity and Evolutionary Biology University of Valencia Valencia Spain

CBMA Centre of Molecular and Environmental Biology Department of Biology University of Minho Braga Portugal

Centro de Investigação de Montanha Instituto Politécnico de Bragança Bragança Portugal

CIBIO InBIO BIOPOLIS Research Center in Biodiversity and Genetic Resources University of Porto Campus Agrário de Vairão Vairão Portugal

CNR IRSA Water Research Institute Verbania Pallanza Italy

Consultants in Aquatic Ecology and Engineering blattfisch e U Wels Austria

Departamento de Ecoloxía e Bioloxía Animal Facultade de Bioloxía Universidade de Vigo Vigo Spain

Department of Biology Faculty of Science University of Zagreb Zagreb Croatia

Department of Ecology and Vertebrate Zoology Faculty of Biology and Environmental Protection University of Lodz Lodz Poland

Department of Evolutionary Biology Kazimierz Wielki University Bydgoszcz Poland

Department of Zoology and Fisheries Czech University of Life Sciences Prague Prague Czech Republic

Department of Zoology Poznań University of Life Sciences Poznań Poland

Department of Zoology University of Cambridge Cambridge UK

Dpt de Zooloxía Xenética e Antropoloxía Fïsica Facultade de Veterinaria University of Santiago de Compostela IBADER Instituto de Biodiversidade Agraria e Desenvolvemento Rural Lugo Spain

Environmental Service Department Sociedad Aragonesa de Gestión Agroambiental Zaragoza Spain

Faculty of Biotechnology and Food Agricultural University of Tirana Tirana Albania

Fondation Hëllef fir d'Natur by natur and ëmwelt Kierchestrooss Luxembourg

Forestry Department CITAB UTAD Centre for Research and Technology of Agro Environment and Biological Sciences University of Trás os Montes and Alto Douro Vila Real Portugal

Institute of Biology Biotechnology and Environmental Protection Faculty of Natural Sciences University of Silesia in Katowice Katowice Poland

Institute of Environmental Sciences Jagiellonian University Kraków Poland

Institute of Marine Biology National Academy of Sciences of Ukraine Odessa Ukraine

Institute of Nature Conservation Polish Academy of Sciences Kraków Poland

MARE Marine and Environmental Sciences Centre Faculdade de Ciências Universidade de Lisboa Lisboa Portugal

Russian Museum of Biodiversity Hotspots Institute of Biogeography and Genetic Resources N Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences Arkhangelsk Russia

School of Geography University of Nottingham Nottingham UK

Swedish Anglers Association Gothenburg Sweden

Technical University of Munich Aquatic Systems Biology Freising Germany

See more in PubMed

Abell, R., Allan, J. D., & Lehner, B. (2007). Unlocking the potential of protected areas for freshwaters. Biological Conservation, 134(1), 48-63.

Dallimer, M., & Strange, N. (2015). Why socio-political borders and boundaries matter in conservation. Trends in Ecology & Evolution, 30(3), 132-139.

Dudgeon, D. (2019). Multiple threats imperil freshwater biodiversity in the anthropocene. Current Biology, 29, R960-R967.

Liu, J., Yong, D. L., Choi, C. Y., & Gibson, L. (2020). Transboundary frontiers: An emerging priority for biodiversity conservation. Trends in Ecology & Evolution, 35(8), 679-690.

Lopes-Lima, M., Sousa, R., Geist, J., Aldridge, D. C., Araujo, R., Bergengren, J., Bespalaya, Y., Bódis, E., Burlakova, L., Van Damme, D., Douda, K., Froufe, E., Georgiev, D., Gumpinger, C., Karatayev, A., Kebapçi, Ü., Killeen, I., Lajtner, J., Larsen, B. M., … & Zogaris, S. (2017). Conservation status of freshwater mussels in Europe: State of the art and future challenges. Biological Reviews, 92, 572-607.

Lopes-Lima, M., Burlakova, L. E., Karatayev, A. Y., Mehler, K., Seddon, M., & Sousa, R. (2018). Conservation of freshwater bivalves at the global scale: Diversity, threats and research needs. Hydrobiologia, 810, 1-14.

Lopes-Lima, M., Riccardi, N., Urbanska, M., Köhler, F., Vinarski, M., Bogan, A. E., & Sousa, R. (2021). Major shortfalls impairing knowledge and conservation on freshwater molluscs. Hydrobiologia, 848, 2831-2867.

Mammola, S., Riccardi, N., Prié, V., Correia, R., Cardoso, P., Lopes-Lima, M., & Sousa, R. (2020). Towards a taxonomically unbiased EU biodiversity strategy for 2030. Proceedings of the Royal Society B, 287, 20202166.

Modesto, V., Ilarri, M., Souza, A. T., Lopes-Lima, M., Douda, K., Clavero, M., & Sousa, R. (2018). Fish and mussels: Importance of fish for freshwater mussel conservation. Fish and Fisheries, 19, 244-259.

Richard, J. C., Leis, E., Dunn, C. D., Agbalog, R., Waller, D., Knowles, S., Putnam, J., & Goldberg, T. L. (2020). Mass mortality in freshwater mussels (Actinonaias pectorosa) in the clinch river, USA, linked to a novel densovirus. Scientific Reports, 10(1), 1-10.

Richardson, M. (1994). Environmental effects of the war in Croatia. Environmental Management and Health, 5, 26-30.

Schwarz, U. (2015). Hydropower projects on the Balkan rivers - Update. RiverWatch & EuroNatur.

Shumilova, O., Tockner, K., Thieme, M., Koska, A., & Zarfl, C. (2018). Global water transfer megaprojects: A potential solution for the water-food-energy nexus? Frontiers in Environmental Science, 6, 150.

Sutherland, W. J., Taylor, N. G., MacFarlane, D., Amano, T., Christie, A. P., Dicks, L. V., Lemasson, A. J., Littlewood, N. A., Martin, P. A., Ockendon, N., Petrovan, S. O., Robertson, R. J., Rocha, R., Shackelford, G. E., Smith, R. K., Tyler, E. H. M., & Wordley, C. F. R. (2019). Building a tool to overcome barriers in research-implementation spaces: The conservation evidence database. Biological Conservation, 238, 108199.

Tickner, D., Opperman, J. J., Abell, R., Acreman, M., Arthington, A. H., Bunn, S. E., Cooke, S. J., Dalton, J., Darwall, W., Edwards, G., Harrison, I., Hughes, K., Jones, T., Leclère, D., Lynch, A. J., Leonard, P., McClain, M. E., Muruven, D., Olden, J. D., … & Young, L. (2020). Bending the curve of global freshwater biodiversity loss: An emergency recovery plan. BioScience, 70, 330-342.

Tonkin, J. D., Olden, J. D., Merritt, D. M., Reynolds, L. V., Rogosch, J. S., & Lytle, D. A. (2021). Designing flow regimes to support entire river ecosystems. Frontiers in Ecology and the Environment, 19(6), 326-333.

Vaughn, C. C., & Hoellein, T. J. (2018). Bivalve impacts in freshwater and marine ecosystems. Annual Review of Ecology, Evolution, and Systematics, 49(1), 183-208.

Zieritz, A., Sousa, R., Aldridge, D. C., Douda, K., Esteves, E., Ferreira-Rodríguez, N., Mageroy, J. H., Nizzoli, D., Osterling, M., Reis, J., Riccardi, N., Daill, D., Gumpinger, C., & Vaz, A. S. (2022). A global synthesis of ecosystem services provided and disrupted by freshwater bivalve molluscs. Biological Reviews, 97(5), 1967-1998.

The impact of invasive Sinanodonta woodiana (Bivalvia, Unionidae) and mussel macroparasites on the egg distribution of parasitic bitterling fish in host mussels