Browsing by Autor "Bernardo Caldas"

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Breaking down silos: Conservation areas for Amazonian flagship terrestrial and freshwater species
(Society for Conservation Biology, 2025) Natalie Shahbol; Melissa Arias; Valeria Boron; Helga Correa Wiederhecker; Bernardo Caldas; Fabiola La Rosa; Robin Naidoo; M Oliveira-da-Costa; Jessica Pacheco; Mariana Paschoalini Frias
Abstract Research into the threats affecting flagship terrestrial and freshwater species in the Amazon has operated within disciplinary and ecological silos, neglecting the interconnectedness between these species and ecosystems. In this study, we aimed to bridge these divides by identifying Amazon areas harboring high jaguar densities and high richness of migratory freshwater species, highlighting the potential co‐benefits of integrated terrestrial and freshwater conservation approaches. We also assessed the risks posed to these areas by habitat and connectivity loss due to impending dam construction, deforestation, and the lack of coverage by area‐based conservation schemes. We found that 17% of the Amazon River Basin is covered by areas of high jaguar density and freshwater migratory species richness, 83% of which are found in Brazil and Peru. A third of these areas are located outside of formal protected areas or Indigenous territories, with Bolivia representing the largest gap in formal protection. The proposed construction of 54 hydroelectric dams and the expansion of deforestation poses an immediate threat to the habitats and connectivity of these areas. Given the risk of an Amazon ecological tipping point, our study underscores the need for integrated terrestrial and freshwater conservation approaches that set in motion international collaboration to secure transboundary flagship and umbrella species.
Identifying the current and future status of freshwater connectivity corridors in the Amazon Basin
(Society for Conservation Biology, 2022) Bernardo Caldas; Michele Thieme; Natalie Shahbol; Maria Eduarda Moraes Sarmento Coelho; Guenther Grill; Paul A. Van Damme; Ricardo Aranha; Carlos Cañas; Camila Kurzmann Fagundes; Nicole Franco‐León
Abstract The Amazon Basin features a vast network of healthy, free‐flowing rivers, which provides habitat for the most biodiverse freshwater fauna of any basin globally. However, existing and future infrastructure developments, including dams, threaten its integrity by diminishing river connectivity, altering flows, or changing sediment regimes, which can impact freshwater species. In this study, we assess 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. We identified that in 2019, 16 of 26 very long (>1000 km) rivers are free‐flowing but only 9 would remain free‐flowing if all proposed dams are built. Among long and very long rivers (>500 km), 93 are considered FCCs. Under the future scenario, one‐fifth (18) of these long and very long FCCs—those that are of critical importance for long‐distance migrants and dolphins—would lose their FCC status, including the Amazon, the Negro, Marañón, Napo, Ucayali, Preto do Igapó Açu, Beni, and Uraricoera rivers. 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.