The large appetites and feeding habits of African forest elephants may actually lead to more plant mass which stores more carbon to help mitigate climate change, according to a new study published on 15 July in Nature Geoscience (1). The authors quantified the impact of elephants on native forests, in particular, the structure, productivity and carbon stocks in Africa’s rainforests.
The international team of researchers incorporated elephant disturbances — in other words, foraging and eating — into the existing Ecosystem Demography model. The well-established computer model simulates demographic processes in forest ecosystems and the authors were able to use data from real forest plots in the Congo Basin to validate the model.
The findings show a reduction of forest stem density due to the presence of elephants actually promotes fewer but larger trees with higher wood density by altering the competition among trees for light, water and space. The higher wood density increases the amount of carbon that forests can store, thereby mitigating some of the effects of climate change.
Elephants are intelligent and highly social species known for their impressive size, which helps them ward off predators like lions and tigers. But also means they have an equally impressive appetite. Forest elephants live in densely wooded rainforests of west and central Africa and mainly feed on trees and plants with low wood density. This essentially means they filter out smaller trees and making more room for larger high wood density tree species that soak up more carbon from the atmosphere.
But these “small” elephants also much more vulnerable than their larger relatives, which means that unfortunately, this elusive subspecies of the African elephant is heading towards extinction at an even faster rate. And if African forest elephants do become extinct, the aboveground biomass in central African rainforests would decrease by seven per cent, according to the authors. In monetary terms, this will cost around US$43 billion, based on a conservative carbon stock price. And of course, would worsen climate change.
The forest elephant population has decreased dramatically — it is less than 10 per cent of what it potentially could be — many of them have probably been killed by poachers to feed the ivory trade while others have been displaced by humans infringing on their habitat.
Berzaghi and colleagues highlight the need for forest elephants to be considered their own species with a separate International Union for Conservation of Nature (IUCN) Red List status, which could help trigger new policies and actions to protect them.
All species play a certain role — often more than one — in their native ecosystem. The study provides further evidence of the important ecosystem services forest elephants provide in helping to stabilise the climate.
Protecting elephant species — and undoubtedly, all species — would not only help conserve this magnificent mammal but would also contribute to the fight against climate change. A growing body of evidence shows that biodiversity is crucial to supporting ecosystems and indeed, for ensuring the future of the human race and the planet. Incredibly, the behaviour of a single species can be linked to global climate impacts.
(1) Berzaghi, F. et al. Carbon stocks in central African forests enhanced by elephant disturbance. Nature Geoscience (2019). DOI: 10.1038/s41561-019-0395-6