Over-hunted tropical forests could make climate change worse

The extinction of large animals from tropical forests could make climate change worse – according to researchers at the University of East Anglia.

New research published in Science Advances reveals that a decline in fruit-eating animals such as large primates, tapirs (pictured above) 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.

Seed dispersal by large-bodied vertebrates happens via the ingestion of viable seeds that pass through the digestive tract intact.??Removing large animals from the ecosystem upsets the natural balance and leads to a loss of heavy-wooded large trees, which means that less CO2 can be locked away.

The study was led by researchers from São Paulo State University in Brazil, in collaboration with UEA, the Spanish National Research Council (CSIC) and the University of Helsinki, Finland.

Prof Carlos Peres, from UEA’s School of Environmental Sciences, said: “Large birds and mammals provide almost all the seed dispersal services for large-seeded plants. 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.

“We show that the decline and extinction of large animals will over time induces 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.”