Elephants been called a lot of things: the world’s largest land creatures, imperiled, majestic, charismatic. Now scientists have a few more terms for describing them: foresters and climate champions.
In the jungles of equatorial Africa, scientists report that forest elephants play an important role in shaping the forest around them as they vacuum up as much as 200 kilograms worth of plants every day. Their appetites influence not just what trees survive but how much carbon the forest stores in leaves and trunks.
“Elephants are the gardeners of the forest,” said Stephen Blake, a Saint Louis University biologist who has spent years studying elephants. “They plant the forest with high carbon-density trees and they get rid of the ‘weeds,’ which are the low carbon-density trees.”
As the biggest animals around, elephants have earned a reputation as “ecosystem engineers.” They spread seeds in their dung, turn forests into savannas, and create trails that extend for kilometers, among other things. Scientists have also pointed to their potential to alter how much carbon gets sucked up by African forests. But that evidence largely came from models, rather than on-the-ground observations. The details of how it works weren’t clear.
Blake and collaborators from French universities set out to better understand how elephants interact with the trees in the forest, and what that might mean for the climate. In the Republic of Congo’s Ndoki Forest, people walked fresh trails left by forest elephants. They tracked which plants showed signs of being eaten and how much of each plant they ate. They also spent three years sifting through some 855 piles of elephant dung to see what seeds were being deposited. The researchers combined this with similar data from other Congo forests to get a detailed accounting of the elephants’ diets. [Continue reading…]