The response of sedimentary dynamics of the Xingu and Tapajós rivers to climate changes and hydropower dams: risks for biodiversity conservation and energy production in Amazonia

Abstract

The Xingu and Tapajós rivers comprise the main hydropower projects planned or under construction in Amazônia. These rivers also stand out due to their specific biodiversity, with emphasis on lithophilic (rocky substrates) and rheophilic (rapids) fishes and endemic birds of flooded areas. Additionally, the Xingu and Tapajós watersheds are hot spots for the expansion of agriculture and pasture activities over Amazônia during the last decades. Climate models forecast an increase of the intensity and/or frequency of extreme events, with special regard to severe droughts, in areas drained by the Xingu and Tapajós rivers. In this context, the sustainable management of hydropower production, agriculture/pasture and biodiversity conservation in the Xingu and Tapajós rivers is a great challenge for a climate change future. Precipitation changes, deforestation and rivers impoundment shift the fluvial sedimentary dynamics (supply, erosion and deposition of sediments). Shifts in sedimentation can affect the characteristics of aquatic or flooded ecosystems as well as the availability and storage of water for hydropower production, agriculture and pasture. This project comprises a multidisciplinary approach to characterize the past hydrology variability (last 3,000 years), the present sedimentary dynamics and biodiversity and forecasting of future sedimentation scenarios and their possible impacts over biodiversity conservation and hydropower production in the Xingu and Tapajós rivers. We will combine methods for reconstruction of paleohydrology, paleovegetation and paleolimnology, present distribution and abundancy of biodiversity (lithophilic and rheophilic fishes, birds from flooded areas and diatoms) and forecasting of precipitation scenarios and their effects over sedimentation. Data produced by this project will help to support strategies for a sustainable management of biodiversity conservation and hydropower production. (AU)