Hidden in the forests of equatorial West and Central Africa lives an elusive species of elephant known as the African forest elephant. Vulnerable to extinction, these animals occupy just a quarter of their historic range, with more than 60 percent of the population being poached in a mere decade. While losing this iconic species would severely impact the local ecosystem, new research suggests that it would also increase atmospheric carbon dioxide, contributing to global warming.
Countries across the world are experiencing extreme weather events and scorching heat – various European nations have suffered unprecedented temperatures this week – at the hands of the climate crisis. To mitigate climate change, we need to drastically curb how much greenhouse gas we pump into the atmosphere.
Without natural carbon sinks like forests, soil, and the oceans, we’d be in even bigger trouble. And that’s where forest elephants come in. A new paper, published in Nature Geoscience, reports that these vast mammals encourage the growth of slow-growing woody trees that remove and store carbon from their surroundings by eating and trampling on fast-growing species that aren’t so efficient.
Without the elephants, these fast-growing plants would rise up, compete with the carbon-sequestering trees, and reduce the forest’s ability to store carbon from the atmosphere. Plants are effective carbon sinks as they absorb carbon dioxide to photosynthesize, releasing oxygen back into the air.
"Lo and behold, as we look at numbers of elephants in a forest and we look at the composition of forest over time, we find that the proportion of trees with high-density wood is higher in forests with elephants," Stephen Blake, assistant professor of biology at Saint Louis University, said in a statement.
Blake and his team formulated a mathematical model to determine the knock-on effects that the disappearance of forest elephants would have. They note that conserving elephants could provide us with a carbon storage service worth $43 billion.
"The simulation found that the slow-growing plant species survive better when elephants are present,” Blake explained. “These species aren't eaten by elephants and, over time, the forest becomes dominated by these slow-growing species. Wood (lignin) has a carbon backbone, meaning it has a large number of carbon molecules in it. Slow-growing, high-wood-density species contain more carbon molecules per unit volume than fast-growing, low-wood-density species. As the elephants ‘thin’ the forest, they increase the number of slow-growing trees and the forest is capable of storing more carbon."
Like other troubled elephant species, forest elephants are equipped with striking ivory tusks. Their dense, slightly rose-colored ivory is particularly desirable in countries like Japan, making them a key target for poachers. A staggering 62 percent of forest elephants were poached for their ivory between 2002 and 2012. While conservationists and anti-poaching teams are working tirelessly to protect them, the dense vegetation in which they live poses a challenge. Meanwhile, forests elephants are threatened by more than poachers, they're hunted for bushmeat and losing their habitat to loggers too.
"The sad reality is that humanity is doing its best to rid the planet of elephants as quickly as it can," Blake said. "Forest elephants are rapidly declining and facing extinction. From a climate perspective, all of their positive effect on carbon and their myriad other ecological roles as forest gardeners and engineers will be lost."