How elephants could potentially save the planet

In findings published in Proceedings of the National Academy of Sciences, Saint Louis University researchers and colleagues report that elephants play a key role in creating forests, which store atmospheric carbon and maintain the biodiversity of forests in Africa.

Dr Stephen Blake, assistant professor of biology at Saint Louis University and senior author on the paper, and Fabio Berzaghi, of the Laboratory of Climate and Environmental Sciences in Gif-Ȳsur-ȲYvette, France, documented exactly how the ecology of megaherbivores had such a strong influence on carbon retention in African rainforests.

“Elephants have been hunted by humans for millennia,” Blake said. “As a result, African forest elephants are critically endangered. The argument that everybody loves elephants hasn’t raised sufficient support to stop the killing. Shifting the argument for elephant conservation toward the role that forest elephants play in maintaining the biodiversity of the forest, that losing elephants would mean losing forest biodiversity, hasn’t worked either, as numbers continue to fall.

“We can now add the robust conclusion that if we lose forest elephants, we will be doing a global disservice to climate change mitigation. The importance of forest elephants for climate mitigation must be taken seriously by policymakers to generate the support needed for elephant conservation. The role of forest elephants in our global environment is too important to ignore.”

Within the forest, some trees have light wood (low-carbon-density trees) while others have heavy wood (high-carbon-density trees).

Low-carbon-density trees grow quickly, rising above other plants and trees to get to the sunlight. Highcarbon-density trees grow slowly; they need less sunlight and are able to grow in shade. Elephants affect the abundance of the second type by feeding more heavily on low-carbondensity trees, which are more palatable and nutritious. This ‘thins’ the forest, much as foresters do to promote growth of their preferred species, a process that reduces competition among trees and provides more light, space and soil nutrients to help the high carbon trees to flourish.

“Elephants eat lots of leaves from lots of trees, and they do a lot of damage when they eat,” Blake said.

“They’ll strip leaves from trees, rip off a whole branch or uproot a sapling when eating, and our data shows that most of this damage occurs to low-carbon-density trees.

“If there are a lot of highcarbon-density trees around, that’s one less competitor eliminated by the elephants.”

ȊȲSaint Louis University. ‘Can elephants save the planet? Researchers discover elephant extinction could have major impact on atmospheric carbon levels’. ScienceDaily, 23 January 2023. Visit bit.ly/3DiIm41.