When we talk about extinction, in particular that of some species that have a high symbolic value (the white bear, the panda, the whale, the dolphin), we always focus on the animal, almost never on the consequences that would have its disappearance on the 'ecosystem. Let's take African elephants as an example: in 2016 there remained just over 400, 000 specimens, compared to 700, 000 five years earlier, and their population continues to decline; we have known almost everything about their ecological role for some time, but only this year, for the first time, a research group from the University of Saint Louis tried to calculate what the impact on the global climate would be if the Loxodonta africana disappeared from the face of the Earth.
The results are not reassuring, and are linked precisely to the ecological role of the elephant, which burns bushes and plants, with a strong preference for those with faster growth, which are devoured and even trodden during meals; this behavior frees the soil for other, slower growing plants. We knew all this, but the work of the team led by Fabio Berzaghi highlights another detail: slow-growing trees have the thickest trunk of lignin, the polymer that covers the walls of plant cells and whose structure is composed of a "backbone" of carbon-based molecules. The more lignin there is in the trunk of a tree, therefore, the greater its ability to absorb carbon, sequestering it from the atmosphere, therefore the greater its effectiveness in fighting climate change.Less elephants, less trees
Thanks to their selection work, the elephants have, over the millennia, contributed to populate the African forests with centuries-old trees, with an extraordinary ability to accumulate carbon: by simply feeding, African elephants help keep the atmosphere clean - a job, calculates the team, which is equivalent to something like 43 billion dollars in works and investments, for the man. It is therefore clear that the disappearance of the elephant would not only cause epochal upheavals in African forests, but would take us several steps backwards in the fight against climate change.