Brazil: Disaster for Birds & Tortoises

Hydroelectric power uses dams to increase the pressure of natural water sources so that more energy can be produced.

Dams can lead to widespread flooding in areas that used to be dry land.

While it was previously known that flooded areas would lose wildlife, it was not well understood how the impact of shrinking animals' habitats into small islands would impact survival.

Not only was it harder for some species to find mates, but wildfires also exacted a deadly toll on some of the islands during an El Nino-driven drought in 1997 and 1998, researchers found.

Post-burn islands retained even fewer wildlife species than islands of similar size that had not been affected by wildfires.

Since Brazil plans to build even more hydroelectric dams in the coming years, researchers urged the government to incorporate their findings into future studies of environmental impact.

"We're only beginning to realize the staggering extent of extinctions in forest areas that remain above water as habitat islands," said Peres.

"The Brazilian government is currently planning to build hundreds of new dams in some of the world's most biodiverse tropical forest regions. But the high biodiversity costs of mega dams should be carefully weighed against any benefits of hydropower production."

Hydroelectric dams were once touted as a major source of clean energy because they do not require the burning of fossil fuels.

However, a series of research papers in recent years has shown they can have devastating effects on fisheries and local communities.

They can also cause spikes in methane and greenhouse gas emissions from rotting vegetation.