Hydropower dams may have damaging effects on species' populations living in surrounding locations, a new study found. These negative effects can lead to the extinction of several species.

There are currently 58,402 dams operating around the world. These dams mainly provide energy and irrigation needs.

Reservoir areas are often deemed as "conservation sanctuaries," protecting many species from deforestation, poaching and hunting activities. However, new findings showed that these so-called sanctuaries might end up contributing to the species' slow extinction.

In the study led by the University of Stirling, the researchers studied the species population data in almost 250 reservoir land-bridge islands. Some of these areas included the Thousand Island Lake in China and the Balbina reservoir in Brazil.

The researchers found that the reservoir islands have about 35 percent less species on average compared with mainland areas nearby.

Notably, they found an 87 percent species demise in one of the South American bird communities on the reservoir islands.

While flooding can cause immediate territory and species loss, the findings suggested that the surviving species are subjected to an "extinction debt." This is when the initial loss is followed by the species extinction which could happen multiple generations later.

"No matter where the dam is located, the island size, or which species are present, there is sustained loss of species, with many in existing dams still potentially facing extinction," said the study's lead author, Isabel Jones, Ph.D.

The findings suggested that more efforts on species conservation should be done in order to prevent long-term species loss on reservoir islands.

Some of the existing practices include setting aside tropical forests. However, study co-author Professor Carlos Peres said this is an illusion.

"But this is a mirage if the remaining terrestrial biota becomes stranded in small islands," said Peres from the University of East Anglia.

Peres added that this situation needs to be analyzed when constructing new infrastructure.

The research was a collaboration among the University of Stirling, the Smithsonian Tropical Research Institute and the University of East Anglia. The research was published in the Biological Conservation journal on May 20.

Photo: Deni Williams | Flickr