Protected French Forests Still Exposed to Noise Pollution Often Underestimated

In popular imagination, a protected forest remains a sanctuary of silence. Yet, beneath birdsong and the rustle of leaves, another soundscape asserts itself. And what if it revealed one of the most troubling blind spots of the current ecological crisis?

Sonosylva listens to protected forests to reveal their soundscape

Since 2024, the Sonosylva project quietly turns tree trunks into listening posts. Led by the National Museum of Natural History, the French Office for Biodiversity, and several partners, this sonic inquiry outfits more than a hundred protected forests. Small recorders, almost invisible, are installed there.

The idea has something of romance and something very modern. Instead of constantly sending field naturalists into the field, these devices capture one minute of sound every quarter-hour. They operate every other day, from spring to autumn. In a single season, that amounts to nearly a million audio files. It is a raw memory of forest life.

But Sonosylva is not only about collecting birdsong. The project also measures technophony. In other words, it evaluates the share of sounds produced by human activities. It also tracks the acoustic phenology of habitats. A protected forest can thus remain biologically rich. It can, however, be traversed by a rumble coming from elsewhere.

Even protected, forests endure human noise far from trivial

The most destabilizing may be here. The protection status is not enough to build a glass bubble around a forest massif. A plane, a road, or a distant construction site can be enough. Even regular traffic can deposit into the air a diffuse noise pollution. It redraws the sensitive map of places.

This noise is not merely unpleasant. It acts like a veil laid over the signals of living beings. For many species, especially birds, amphibians, or certain insects, hearing enables reproduction, to feed, to alert, or to flee. When this channel becomes blurry, the forest is not simply louder. It becomes harder to inhabit.

Noise disrupts wildlife long before the forest seems damaged

Scientific work accumulated over roughly fifteen years shows that human-made noise can modify animal behavior, well beyond cities. Landmark studies, published in Science or PNAS, have already demonstrated it. Noise can mask useful signals, increase physiological stress, and displace certain species. Even favorable areas can then be avoided.

This displacement has cascading consequences. Birds change their singing times. Some predators hunt less effectively. Other species avoid entire sectors because the background sound is too unstable. The forest may look intact to the naked eye, but its inner functioning becomes off-kilter. The visible biodiversity can then mask a fragile biodiversity.

That is precisely what makes ecoacoustics fascinating. By listening to the share of biophony, geophony, and technophony, researchers document not only the presence of animals. They also identify invisible imbalances. These are moments when the forest still stands, but gradually loses part of its natural conversation.

Noise pollution also disturbs plants and the links of life

The most surprising part may be the plants. Plants don’t hear like animals do, but recent research suggests they respond to vibrations and to certain mechanical signals. Studies published in 2025 and 2026 explore the possible effects of anthropogenic noises on growth, flowering, or certain physiological responses.

The strongest, for now, effect remains often indirect. When noise disrupts pollinators, seed dispersers, or herbivores, plants also pay the price. A noisy forest may thus see changes in plant reproduction. It can also weaken the ecological services that sustain its diversity.

For a long time, noise pollution was thought to be mainly a human problem. It was linked to sleep, health, or comfort. Yet Sonosylva shows that it also acts as an ecological stress. It can alter a habitat without felling a single tree. As this listening to life advances, another idea becomes evident. Protecting a forest may also mean defending its acoustic quality.