Dams Induce Widespread Species Extinction in the Amazon Forest, Research Says

Deforestation, habitat loss, and fragmentation are all related and contributing to the current biodiversity catastrophe, with hydropower being responsible for much of the deterioration.

River damming often floods extensive low-elevation regions in lowland tropical forests, whereas formerly ridgetops frequently become isolated forest patches.

Hydropower dams cause extensive extinctions of species

(Photo : Vlad Hilitanu/Unsplash)

In a recent study, researchers from the University of East Anglia, Portugal, and Brazil employed network theory to better understand how insular habitat fragmentation impacts tropical forest biodiversity.

This method saw habitat patches and species as interconnected entities at the landscape scale, including a species-habitat network, as per ScienceDaily.

"Emergent features of species-habitat networks in an insular forest environment," the study's title, was published today in the journal Science Advances.

The authors investigated 22 habitat patches, which included forest islands and three continuous forest areas, produced by the Balbina Hydroelectric Reservoir, South America's biggest.

The 608 species studied belonged to eight different biological groups: mid-sized to large mammals, tiny non-flying mammals, understorey birds, reptiles, frogs, dung beetles, orchid bees, and plants.

The study found widespread species extinction, particularly among large-bodied species, but this differed across the plant, vertebrate, and invertebrate groups.

The survival of species variety was dictated by island size, with just a few islands containing the greatest diversity.

As large swaths of tropical forest are fragmented and separated into small habitat patches, they become more uncommon.

The destruction of bigger forest sites will have the biggest impact, most likely resulting in secondary extinctions of species that only exist at a single location or have larger spatial needs.

Small forest patches, on the other hand, support more species than one or a few larger patches of similar total size, hence the loss of smaller sites is also predicted to result in secondary extinctions.

Professor Carlos Peres, the co-author of the paper, is a Professor of Environmental Studies at the University of East Anglia.

He stated: "Tropical developing nations are still hellbent on building massive hydropower reservoirs in the name of 'green' energy."

Dr. Ana Filipa Palmeirim, a researcher at CIBIO-University of Porto, led the study, which looked at a complex landscape as a whole

This method enabled them to uncover previously unknown patterns, such as the simplification of the network structure and changes in important network parameters caused by the dam's loss of species.

"The beauty of our study lies in the integration of advanced network and statistical analysis, with the natural history of high-quality species inventories from an incredible tropical living lab," stated Dr. Carine Emer, a co-author of the paper from the Rio de Janeiro Botanical Garden.

More than 3,000 islands were formed 35 years ago as a result of the Uatum River damming, and they were able to comprehend the functioning of such a complex and diverse human-modified ecosystem by examining them.

Also Read: New Species of Highly Threatened Marmosets Discovered Hidden in Amazon Forest

Over 10,000 species risk extinction in Amazon

According to the draft of a historic scientific report issued on July 15, 2021, more than 10,000 species of plants and animals are at great risk of extinction due to the devastation of the Amazon rainforest, 35% of which has already been deforested or damaged, as per Reuters.

The 33-chapter study, produced by the Science Panel for the Amazon (SPA), pulls together studies on the world's biggest rainforest from 200 experts from across the world.

It is the most extensive evaluation of the forest's status to date, and it demonstrates both the Amazon's critical role in world climate and the grave threats it faces.

Cutting deforestation and forest degradation to zero in less than a decade is "essential," according to the report, which also calls for extensive rehabilitation of previously devastated regions.

The rainforest is an important barrier against climate change because of the carbon it absorbs and stores.

According to the analysis, the Amazon's soil and plants contain over 200 billion tonnes of carbon, which is more than five times the world's yearly CO2 emissions.

Furthermore, the continuous degradation caused by human intervention in the Amazon puts over 8,000 indigenous flora and 2,300 creatures at risk of extinction, according to the research.

University of Brasilia professor Mercedes Bustamante noted that science demonstrates that humanity face possibly permanent and catastrophic dangers as a result of various problems, including climate change and biodiversity reduction.

Deforestation in Brazil has increased dramatically since right-wing President Jair Bolsonaro entered office in 2019, reaching a 12-year high last year and eliciting widespread condemnation from foreign governments and the general public.

Bolsonaro has asked for mining and agribusiness in Amazonian protected areas and has undercut environmental enforcement agencies, which environmentalists and scientists claim has directly contributed to escalating devastation.

Related article: Brazil Records Big Increase in Amazon Forest Fires