Essential to soil health and carbon sequestration, fallen leaves are much more than a melancholy symbol of autumn. A veritable fuel for ecosystems, they nourish the soil, harbour an abundance of biodiversity and play an active part in the carbon cycle.
We sweep them up, blow them away, sometimes dread them... Yet beneath our feet, these decomposing leaves play an essential role: they return to the soil the nutrients needed for plant growth and contribute to the formation of humus, a reservoir of organic matter and carbon. Their slow transformation depends on the climate, the type of soil and the tree species present - hardwoods, for example, offer a more easily decomposable litter than softwoods.
This carpet of dead leaves is also home to a discreet but abundant fauna: mites, springtails, earthworms, fungi and bacteria work together to maintain soil fertility and the stability of ecosystems. Without them, nature would lose one of its invisible driving forces.
Originally published in The Conversation, this article was picked up by Futura and Science & Vie, The event was a great success, with over 50,000 hits in just a few days - Proof that fallen leaves are still making waves!