Greater biodiversity allows forests to better resist the effects of climate change and continue to provide the same services, starting with the recycling of carbon and nutrients, according to two studies published Monday.
“When there is more biodiversity, we can maintain the same functioning of the ecosystem despite more extreme climatic conditions. By promoting greater biodiversity, we can mitigate the consequences of climate change,” summarizes Stephan Hättenschwiler, research director at CNRS, who participated in both studies, to AFP.
The first, published in the journal Global Change Biology by researchers based in Germany and France, shows through modeling that the plant diversity of a forest or meadow protects it from temperature extremes, thus promoting ecosystem processes such as decomposition.
The soil can therefore continue to play its role as a carbon sink.
The decomposition of dead parts of plants, such as the leaves that fall in the fall, constitutes “the fuel” of the carbon and nitrogen cycles, a process essential for the proper functioning of ecosystems and the natural storage of carbon. in the soils.
The second study, published in the journal PNAS by scientists based in China and France, is experimental.
They observed the effects of different mixtures of leaf litter and decomposer organisms in different types of forests under drought conditions. This normally tends to slow down decomposition.
But the study showed that “biodiversity has the potential to offset the negative effects of drought,” emphasizes Stephan Hättenschwiler.
The normal process of decomposition and recycling of elements could in fact be maintained by increasing the diversity of plants and the complexity of decomposer communities (insects, centipedes, mites, etc.) despite a negative impact of drought.
“These findings suggest that promoting biodiversity represents an important lever for maintaining essential ecosystem functions with current climate change,” the authors conclude in the study.
“Instead of favoring monocultures, we must do everything to make our forests more diverse,” adds Stephan Hättenschwiler. “It would be a mistake to go quickly and plant monocultures to increase carbon storage over a large area,” he adds.
In France, forest carbon sinks are working less well than expected. The State has decided to plant a billion trees of diverse species adapted to the future climate over a decade.