Freshwater connectivity corridors in the Amazon Basin

We assessed critical rivers that need to be maintained as freshwater connectivity corridors (FCCs) for selective freshwater species long-distance migratory fishes and turtles (both with migrations >500 km) and river dolphins.
We define FCCs as river stretches of uninterrupted river connectivity that provide important riverine and floodplain habitat for long-distance migratory and other species and that maintain associated ecosystem functions. We assessed more than 340,000 km of river, beginning with an assessment of the connectivity status of all rivers and then combining river status with models of occurrence of key species to map where FCCs occur and how they could be affected under a scenario of proposed dams. Under the future scenario, one-fifth (18) of the 26 long and very long FCCs would lose their FCC status, including the Amazon, the Negro, Marañon, Napo, Ucayali. To avoid impacts of poorly sited infrastructure, we advocate for energy and water resources planning at the basin scale that evaluates alternative development options and limits development that will impact on FCCs. The results also highlight where corridors could be designated as protected from future fragmentation.
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