Hydroelectric dams drastically reduce tropical forest biodiversity

A press release from the University of East Anglia: Widely hailed as ‘green’ sources of renewable energy, hydroelectric dams have been built worldwide at an unprecedented scale. But research from the University of East Anglia reveals that these major infrastructure projects are far from environmentally friendly.

A study published today in PLOS ONE reveals the drastic effects of the major Amazonian Balbina Dam on tropical rainforest biodiversity. The research reveals a loss of mammals, birds and tortoises from the vast majority of islands formed by the creation of the vast Balbina Lake, one of the world’s largest hydroelectric reservoirs.

Lead author Dr Maíra Benchimol..., a former PhD student at UEA and now at Universidade Estadual de Santa Cruz, Bahia, Brazil, said: “Hydroelectric dams have been thought to be an environmentally friendly source of renewable power – and in recent years they have been built to supply the burgeoning energy demands of emergent tropical countries. Previous studies have shown that large dams result in severe losses in fishery revenues, increases in greenhouse gas emissions, and socioeconomic costs to local communities. Our research adds evidence that forest biodiversity also pays a heavy price when large dams are built.

Prof Carlos Peres, from UEA’s School of Environmental Sciences, said: “Of course, it is widely known that dams cause massive population losses in terrestrial and tree-dwelling species within lowland forest areas that are flooded. However, we’re only beginning to realize the staggering extent of extinctions in forest areas that remain above water as habitat islands.

“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.”...

Near Balbina Dam in Brazil, shot by Seabirds, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license