No one seems to argue that life on earth is in decline ; that flora and fauna suffer the consequences of human activities to the point that the eloquent concept of “the sixth extinction” has been coined.
That is why the report by Nick Gotelli, professor of biology at the University of Vermont, published in the journal Science, has been so surprising.
Gotelli has re-examined the data from a hundred long-term studies carried out in all the ecosystems of the Earth – the poles, the oceans, the tropical forests, the deserts … – and has concluded that the number of species or not it has varied a lot or even increased! The figures make it very clear: an increase has been detected in 51% of cases, and a decrease in 41%. And always, the change has been modest
Because the key is not in the quantity . What has been observed is a significant transformation in the type of species that predominate in habitats.
If we take into account this criterion, 80% of the ecosystems have undergone a significant change ; that is, other types of animals and plants have colonized biological communities.
Gotelli believes that environmental policies, so far focused on preventing species numbers from declining, should change accordingly. And he gives as an example, the destruction of corals, replaced by algae, or that of anchovies, which disappear while the number and variety of jellyfish proliferates.
The problem, then, is not the existence of a “loss of biodiversity” but of “change in biodiversity”, with consequences that are often also dire.
