This Thursday, May 5, is Earth Overshoot Day in France: we’ve used up all the resources the planet can renew in one year. In this global context of degradation of natural environments, a study by the United Nations Environment Program gives us some actions: the reintroduction of 20 large mammals would restore the ecological balance of large natural planets. explanation.
The mission of the United Nations Environment Program is to help countries implement environmental policies. At the beginning of this year, it published a study in collaboration with the NGO to resolve which was recently passed on by the magazine Futura Science† It identifies how the reintroduction of 7 predators and 13 herbivores would restore large natural areas.
These mammals would be keystone species, that is, they would have a disproportionate effect on their environment relative to their population. Pollinators or earthworms, for example, are keystone species because entire ecosystems depend on them. This is also the case with the European bison, wolf or lynx.
“In Europe, the reintroduction of European bison, Eurasian beaver, reindeer, wolves and lynx would restore historic populations of large mammals in 35 ecoregions. †
Futura Science according to the United Nations Environment Program study
Restore large natural ensembles
To conduct this study, the scientists compared the current populations of these 20 mammal species to a reference period: the year 1500. At that time, forced to relocate under pressure from predators, the large populations of herbivores maintained vast grasslands. Vegetation, the basis of the food chain, was constantly renewed through grazing. It, in turn, supported many herbivorous species and so on.
Today, only 15% of the land on Earth is occupied by large mammals. The study has already identified 190 regions of the planet where a short-term reintroduction could be possible.
Grasslands are a carbon sink
While grassland and steppe ecosystems are home to significant biodiversity, they have another major advantage: they sequester large amounts of carbon, just like forests or oceans. Restoring these natural environments should therefore play an important role in mitigating climate change.
Such experiments have already been conducted all over the world: the Zimov family started the process about ten years ago in Pleistocene Park, in northern Siberia. The reintroduction of herbivores to this region of the world has restored a highly productive steppe ecosystem. It could also, if implemented on a large scale, reduce permafrost melting.
“We see a real craze for ecosystem restoration and nature-based solutions. We need to ensure that our conservation efforts go hand in hand with a return to the diversity and abundance of life on Earth (…). »
dr. Carly Vynne, study author
What if we enter the era of natural recovery?