From Monday October 21, Colombia will host the 16th edition of the COP on biodiversity, with the ambition of stimulating the implementation of nature conservation objectives by 2030. Among these objectives: the preservation and reintroduction of extinct or threatened species.
The European bison, for example. It disappeared in the wild almost a century ago, victim of hunting, population pressure and deforestation. But since the 1950s, it has been the subject of reintroduction programs, which “started with captive individuals, with a phase of re-acclimatization to the natural environment which can sometimes last decades. The idea is to let live !”explains François Sarrazin, professor of ecology, conservation specialist at the Natural History Museum of Paris.
“Let it live” is what we call rewilding. And it works: nearly 7,000 bison are now present in the wild in eastern Europe, from Poland to Ukraine via Belarus and even our Swiss neighbors.
The forests in which bison live also benefit: “More and more converging elements show that this type of animal has positive effectsunderlines François Sarrazin. By the movement of seeds, the plants which are consumed and rejected further, by the fact that they trample the soil, by the fact that they will consume certain plants and therefore leave room for other plants that they do not consume…”
These wild species also allow forests to store more CO2. This is what scientists proved last year. They listed nine species that play a sort of landscaper role, and help facilitate carbon capture. Among them: the forest elephant, the musk ox, and of course the bison.
Much more discreet than the bison, and regularly forgotten in debates on biodiversity: the earthworm. “When we talk about biodiversity, we think of mammals : the gorilla, the elephant, the wolf… But all the fauna that lives in the ground has been excluded until nowsays Christophe Gatineau, an agronomist who lives in the countryside near Limoges and who has just created the Earthworm Defense League. People often say that earthworms are ‘ugly’. But an earthworm is almost majestic, in fact ! He moves almost like a snake.”
Christophe Gatineau cultivates his leeks, carrots and tomatoes with the greatest care, and is well aware of the work that earthworms do every day under our feet: “The worm will swallow earth or organic matter, and mix it with clays, like we knead bread dough. It is the only one that can do that. And at the same time it will have an impact on the porosity of the soil, with better water retention, better infiltration…”
“Thanks to it, oxygen will be able to penetrate the soil. So having earthworms in your soil means that the soil is alive.”
Christophe Gatineau, agronomistat franceinfo
Earthworms are also a source of food for other species, the robin for example, which loves earthworms. But like many other species, worms are also threatened. Soil impoverishment, overly invasive plowing techniques: these invertebrates face all kinds of pressures, notably the use of pesticides. “An application of glyphosate at the recommended dose will not kill earthwormsspecifies Céline Pelosi, research director at INRAE in Avignon. On the other hand, the repeated use of doses of glyphosate can lead to effects on activity, reproduction, growth… and therefore, ultimately, reduce the long-term capacity of earthworm populations to maintain themselves. “
During the last biodiversity COP two years ago, States committed to halving the risks linked to pesticides by 2030.
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