Extinction of large animals aggravates climate change

The extinction of large animals from tropical forests could make climate change worse, new research suggests. Removing large animals from the ecosystem leads to a loss of heavy-wooded trees, meaning less CO2 can be locked away.

The news comes following a study led by researchers from São Paulo State University in Brazil, in collaboration with the University of East Anglia (UEA), the Spanish National Research Council (CSIC) and the University of Helsinki.

Their research suggests that a decline in fruit-eating animals, such as large primates, tapirs and toucans, could have a knock-on effect for tree species.

This is because large animals disperse large seeded plant species often associated with large trees and high wood density – which are more effective at capturing and storing carbon dioxide from the atmosphere than smaller trees, explains a press release.

“Several large vertebrates are threatened by hunting, illegal trade and habitat loss. But the steep decline of the megafauna in overhunted tropical forest ecosystems can bring about large unforeseen impacts,” UEA Professor Carlos Peres said in a statement.

He added that the decline and extinction of large animals could induce a decline in large hardwood trees. He explained: “This in turn negatively affects the capacity of tropical forests to store carbon, and therefore their potential to counter climate change.”

The research team studied data from more than 2,000 tree species in Brazil’s Atlantic Forest, and more than 800 animal species.

They found that frugivores – or small birds, bats and marsupials that are not targeted by hunters – are only able to disperse small seeds.

Meanwhile, large heavy-wooded trees, which can capture and store greater amounts of carbon, are associated with larger seeds that are only dispersed by large animals.

The study ‘Defaunation affects carbon storage in tropical forests’ is published in the journal Science Advances.

Photo credit: Linda Tanner/ CC BY 2.0

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