Mega-dams and extreme rainfall: disentangling the drivers of extensive impacts on Amazon Forests

What is it about?

Our study demonstrated that mega-dams were mainly responsible for the high forest mortality in the upper Madeira River basin after the 2014 extreme flood, with forest loss rates at least five times higher when compared to the losses resulting from rainfall extremes. In addition, the results also showed, in an unprecedented way, that the extreme rainfall anomalies, probably triggered by global warming and intensified in the last decades, also represent a key driver of forest mortality in the Amazon, even in areas not affected by dams, as observed for the Beni, Guaporé, Madre de Dios and Mamoré River basins. Finally, the interaction between extreme rainfall events, and the installation of mega-dams has negative consequences of extensive magnitude for the Amazon rich biodiversity.

Featured Image

Photo by Nathalia Segato on Unsplash

Photo by Nathalia Segato on Unsplash

Why is it important?

We showed that the mega-dams were the main driver of tree mortality in Madeira basin forests after the 2014 extreme flood. The proliferation of dams and the increase of uncertainties about climatic anomalies place at risk different ecosystems in the Amazon basin, threatening their rich biodiversity with more drastic effects on floodplain forests. Furthermore, the interaction between the new flood pulse, as controlled by the hydroelectric dams, and the new scenario of global climate uncertainties increases the difficulty of forecasting the long-term environmental impacts of mega-dams in the Amazon.

Perspectives