Decline in large animals could worsen climate change

Extinction of large animals from tropical forests could make climate change worse as these animals are crucial in dispersing trees with dense wood which are more effective at capturing and storing carbon dioxide from the atmosphere than smaller trees, a study says.

A decline in fruit-eating animals such as large primates, tapirs and toucans could have a knock-on effect for tree species, the findings showed.

"We show that the decline and extinction of large animals will, over time, induce a decline in large hardwood trees. This in turn negatively affects the capacity of tropical forests to store carbon and therefore their potential to counter climate change," said one of the researchers,Carlos Peres, from the University of East Anglia in England.

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, the researchers explained.

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 which are not targeted by hunters -- such as small birds, bats and marsupials -- are only able to disperse small seeds, which are associated with small trees.

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

"The big frugivores, such as large primates, the tapir, the toucans, among other large animals, are the only ones able to effectively disperse plants that have large seeds. Usually, the trees that have large seeds are also big trees with dense wood that store more carbon," Professor Mauro Galetti from Sao Paulo State University in Brazil explained.

The findings appeared in the journal Science Advances.