Experts have found that biodiversity in the Amazonian region may be at risk due to the unprecedented development of hydroelectric dams.
Through the years, major infrastructure sites that generate electricity from hydropower have increased in number. Although these facilities provide benefits, a new study discovered that mammals, tortoises and birds may face the risk of extinction if exposed to massive dams.
Researchers from the University of East Anglia conducted the study by assessing the patterns at which medium and large populations of arboreal and terrestrial vertebrates—35 species of birds, tortoises and mammals—would react to an environment that had undergone 26 years of archipelagic changes.
Such modifications include changes in habitat quality and landscape formation in a large hydroelectric facility located in the Central Amazonia.
The facility where they conducted their biodiversity surveys is called the Balbina Dam, which isolates 3,546 land-bridge islands due to 3,129 square kilometers of primary forests. A total of 37 islands, plus three nearby forests, were made into study subjects, where a combination of four survey methods were implemented.
The researchers found forest habitat effects that may explain the sequence of vertebrate extinction. Land and tree-inhabiting vertebrates were also assessed in the 40 forest locations. Additional investigations were also made to comprehend the extent of forest degradation using high-quality satellite images of plants in the islands.
The findings of the study published in PLOS ONE show that there is an indication of massive loss of animals on the islands after 26 years of isolation, even in the midst of extreme protection measures employed by the biggest biological reserve in Brazil.
Because of the development of the Balbina Lake, large vertebrates ceased from the majority of the islands. The researchers also found that only 25 of the 3,546 islands created are now able to protect four-fifths of the 35 study subject species. The study also found that the most vital parameter in determining the number of vertebrates left is the size of the island.
"Hydropower is an effective way, in many landscapes, to generate power," said Carlos Peres, co-author and Brazilian professor at the university's School of Environmental Sciences. "Yet its efficacy depends on topography." He cited Brazil as an example. Because of the country's lowlands, hydroelectric facilities must develop massive dams to elevate water levels so that they can form a torrent. For those with sharper slopes, such as in the mountains of Colorado, smaller facilities are required.
"We're watching extinction unfold right in front of us," said Peres. "We uncovered astounding local extinction rates, even in areas that belong to a biological reserve and are protected from hunting."
Photo: Scott Oves | Flickr
