A study examines how dams contribute to fragmentation of freshwater fish habitats. Dams contribute to flood protection, energy supply, and water security, but they also threaten freshwater fish habitats. To uncover the degree to which dams fragment freshwater fish habitats, Valerio Barbarossa and colleagues combined location data for 39,912 extant global dams and 3,681 future hydropower dams larger than 1 MW with the geographical ranges of 9,794 fish species that live either partially or exclusively in flowing freshwater bodies. The authors determined the habitat fragmentation for each species and found that the contribution of extant dams to habitat fragmentation is highest in China, India, South Africa, the United States, and Europe. In contrast, the contribution of future dams to habitat fragmentation was estimated to be highest in the subtropics and tropics, especially for species that inhabit the Amazon, Congo, Niger, Mekong, and Salween river basins. The findings further suggest that future dams may disproportionately affect fish that complete their life cycle in freshwater rather than fish that migrate between oceans and rivers, according to the authors.
Article #19-12776: "Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide," by Valerio Barbarossa et al.
MEDIA CONTACT: Valerio Barbarossa, Radboud University Nijmegen, NETHERLANDS; tel: +31644741179; email: v.barbarossa@fnwi.ru.nl
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Proceedings of the National Academy of Sciences