Noticias

The Amazon River Basin has Earth’s most extensive seasonally flooded floodplain forests. These ecosystems harbor communities of trees and animals adapted to prolonged flooding, including fruit-eating fish. When fish eat fruits, they often swallow intact seeds and move them away from maternal trees, contributing to natural forest regeneration. Nevertheless, floodplain deforestation, hydrological and climatic changes, and overfishing threaten this interdependency. In a basinwide analysis of fruiteating fish species richness patterns, we found floodplain forest extent, richness of tree species, and flood duration to be the most critical landscape and ecosystem features. We conclude that the long-term survival of fruit-eating fish and, in turn, the long-term sustainability of floodplain forests depend on fish accessing diverse and hydrologically functional floodplain forests.
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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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We analysed how differences in dietary preferences influence the spatial distribution and habitat associations of species at the landscape scale.
We used diet data to classify species into feeding guilds (frugivores, herbivores, piscivores, fin and scale feeders and planktivores) and three proxies of habitat association derived from satellite products: floodplain extent, landscape heterogeneity and flood duration.
Frugivores, piscivores and fin and scale feeders presented similar patterns of habitat associations, with frugivores occupying wider areas of floodplain and greater landscape heterogeneity. Herbivores and planktivores were associated with smaller floodplain extents and lower landscape heterogeneity. All feeding guilds were associated with similar levels of flood duration.
This work highlights the importance of understanding species habitat associations by fish as well as food resource dynamics and floodplain dependence. This realization is critical for assessing the impact of anthropogenic activities on freshwater ecosystems.
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Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by this Earth’s largest and most biodiverse river basin.
The paper, published in Science and led by researchers from Cornell University, develops a multiobjective optimization to identify portfolios of sites that simultaneously minimize impacts on river flow, river connectivity, sediment transport, fish diversity, and greenhouse gas emissions while achieving energy production goals. Findings offer a transferable model for the evaluation of hydropower expansion in transboundary basins.
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We UPDATED our database (version 2-2022) to provide the most recent and complete fish species distribution records covering the whole Amazon drainage.
The new version recorded 2,500 validated freshwater native fish species (+94 species), 300,000 georeferenced records, results from an extensive survey of species distribution including 800 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project.
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figshare Database link

New website to visualize and download freshwater fish biodiversity data at different spatial scales:
Freshwater Fish Distribution & Ecology Website

In this paper, published in Geomorphology, we developed a framework to define a river classification protocol adapted to large rivers with application to the Amazonian rivers using two interlocked hierarchical spatial scales: the landscape unit at the basin scale and the reach unit at the local scale. Our framework relies on open-source geospatial data, reproducible and automatic methods to extract the geomorphological attributes of the river network, and on statistical modelling. We then described the spatial patterns of obtained river types within the basin.
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