The extinction of critically endangered elephants could amplify global warming, scientists have warned.
As if the prospect of Earth's biggest land mammal disappearing forever wasn't bad enough, losing them would have a potentially devastating impact on the planet's second-biggest rainforest.
The elephant population in the Congo Basin, which spans several countries in central and western Africa, has plummeted in the past decade - down 60% to an estimated 40,000, according to the Wildlife Conservation Society.
Poaching is a major cause of their decline, with thousands killed every year for their ivory tusks.
Researchers say that if the animals were to completely vanish, the Congo's rainforest - second to Brazil's Amazon - would lose up to 9% of its ability to capture atmospheric carbon.
"If we lose forest elephants, we will be doing a global disservice to climate change mitigation," said Stephen Blake, assistant professor of biology at Saint Louis University.
"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."
The crucial role of elephants
Professor Blake is senior author of a new paper in Proceedings of the National Academy of Sciences.
His team's research describes how crucial elephants are to Africa's rainforests, maintaining their valuable status as a carbon sink, when they absorb more carbon dioxide than they emit.
Elephants favour low carbon density trees when it comes to feeding, as they are more nutritious, promoting the growth of higher carbon density trees.
The elephants' feeding habits "thins" the forest, which reduces competition among the trees and provides more light, space, and soil nutrients to the high carbon trees.
When elephants do feed from high carbon trees, it's the often large fruit that grows from them - the seeds from which pass through the animals' gut undamaged.
These are released in the elephants' dung, primed to germinate and grow into some of the forest's largest trees.
'Save the elephants - help save the planet'
Professor Blake hailed them as "the gardeners of the forest" - and said the research was yet more reason to provide them with better protection.
He added: "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."
The WWF estimates there are 415,000 elephants left across Africa, and 40,000 to 50,000 in the wild in Asia.