4 January 2017
Stephanie R. Januchowski-Hartley, Céline Jézéquel, Pablo A. Tedesco
Tropical rivers are experiencing an unprecedented boom in dam construction. Despite rapid dam expansion, knowledge about the ecology of tropical rivers and the implications of existing and planned dams on freshwater-dependent species remains limited. Here we evaluate fragmentation of fish species ranges, considering current and planned dams of the Magdalena River basin, Colombia. We quantify the relationship between species range and body size and use a vulnerability limit set by this relationship to explore the influence that fragmentation of species ranges has on extinction risk. We find that both existing and planned dams fragment most fish species ranges splitting, them into more vulnerable populations. Importantly, we find that migratory species, and those that support fisheries, are most affected by fragmentation. Our results highlight the dramatic impact that dams can have on freshwater fishes and offer insights into species extinction risk for data-limited regions.