Elephants are ‘gardeners of the forest’ — and that could help save the planet

ST. LOUIS, Mo. — Elephants have the ability to be the “gardeners of the forest,” a skill that may hold the key to saving the environment from climate change. Researchers from Saint Louis University say Earth’s largest land animals slow global warming. They eat low carbon density trees, creating more space for greenery that stores more.

Unfortunately, the five-ton creatures, prized for their ivory tusks, have been driven to the brink of extinction by poachers — even though they are vital for maintaining Africa’s biodiversity.

Elephants have been hunted by humans for millennia,” says senior author Stephen Blake, Ph.D., assistant professor of biology at Saint Louis University, in media release.

“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 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,” Blake continues.

“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 policy makers to generate the support needed for elephant conservation. The role of forest elephants in our global environment is too important to ignore.”

Elephants literally thin out less helpful trees

Elephant populations have experienced significant declines over the last century. There are now only about 400,000 left in Africa, and an estimated 30,000 in Asia. A century ago, they were a common sight across both continents. Today, elephants also face added threats from habitat loss and global warming.

The study, published in the Proceedings of the National Academy of Science, documents their influence on carbon retention for the first time. If they disappear, the rainforest of central and west Africa — the second largest on Earth — will lose six to nine percent of their ability to capture atmospheric carbon, the new study finds.

Some trees have light wood and others heavy, low and high carbon, respectively. The former grow quicker, rising above other plants and trees to get to the sunlight. The latter need less sunlight and are able to thrive in the shade.

Elephants and other mega-herbivores affect the abundance of these plants by feeding mainly on low carbon density trees. They are more palatable and nutritious. This preference “thins” the forest, much like lumberjacks, boosting their favorite species. The phenomenon reduces competition, providing more sunlight, space, and soil nutrients for 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 adds. “They’ll strip leaves from trees, rip off a whole branch or uproot a sapling when eating, and our data shows most of this damage occurs to low carbon density trees. If there are a lot of high carbon density trees around, that’s one less competitor, eliminated by the elephants.”

Elephants also ‘plant’ their own trees

Elephants are also excellent dispersers of the seeds of high carbon density trees which produce large nutritious fruits they eat. Those seeds pass through the elephants’ gut undamaged. When released through their feces, they are primed to germinate and grow into some of the largest trees in the forest.

“Elephants are the gardeners of the forest,” the researcher says. “They plant the forest with high carbon density trees and they get rid of the ‘weeds,’ which are the low carbon density trees. They do a tremendous amount of work maintaining the diversity of the forest.”

Elephants are directly tied to influencing carbon levels in the atmosphere. High carbon density trees store more carbon from the atmosphere in their wood than low carbon density trees, combating global warming.

“Elephants have multiple societal benefits,” Blake explains. “Kids all over the world play with stuffed elephants in bedrooms. African forest elephants also promote rainforest diversity in a multitude of ways.”

It underlines the importance of conserving forest elephants of the Congo Basin and West Africa. Communities are already “functionally extinct” in many areas. Numbers are so low they have no significant ecological impact.

“The illegal killing of elephants and the illegal trade remains active,” Blake concludes.

“Ten million elephants once roamed across Africa, and now there are less than 500,000, with most populations living in isolated pockets. These elephants range from endangered to critically endangered, with their numbers plummeting by more than 80 percent in the last 30-plus years. Elephants are protected under national and international law, and yet poaching continues. These illegal killings must stop to prevent forest elephant extinction. Now we have a choice. As a global society, we can continue to hunt these highly social and intelligent animals and watch them become extinct, or we can find ways to stop this illegal activity. Save the elephants and help save the planet, it really is that simple.”

South West News Service writer Mark Waghorn contributed to this report.

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