Built in the 1980s, the Balbina Dam is one of dozens of large dams across rivers in the Amazon Basin. Such dams might leave behind seemingly green patches of forest, but our new research has shown these disconnected patches of forest are no longer able to support thriving ecosystems.
The dam created one of the largest reservoirs in South America which stretches for almost 100km northwards through largely undisturbed rainforest. As this is a relatively hilly part of the Amazon basin, more than 3,500 islands formed as the reservoir filled up. What were once ridges or hilltops became insular forest patches.
