Heritage: coastal dunes, a treasure to be preserved

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Seven days a week during the summer, they patrol the coastal beaches at the foot of the Pilat Dune . Agents from the National Forestry Office (ONF) are on the front line when it comes to fire risks. "So, we're adapting the signage in the forest, at the entrances to the forest for the public, so they can be informed that the alert level has gone to orange, meaning a high risk," explained Caroline Fourcade, an ONF technician.

Since the devastating fires of 2022 in the region, the environmental police have been even more vigilant during their patrols. "We are mainly sending a prevention message regarding the fire risk that lies behind all this. For the safety of people who spent the night, if a fire had broken out during the night, or possibly because people were lighting fires, they could be the cause of a disaster," explained Fabrice Carré, a technician with the organization.

In Gironde, fire is the primary threat to sand dunes. During fires, the vegetation behind the dunes disappears, and nothing holds back the sand, which recedes from the coastline, pushed by the wind. Mechanically, the sea gains ground. In Pilat, more than 80 meters have been lost in just six years. Mathieu Brugère is a forestry technician who has seen erosion permanently disrupt the landscape. "There, we have the remains of stumps that suggest we once had a forest above us, even extending a little further west. And we also have remnants of forest soil. The crust you see is the old forest soil; it's not soil from a previous era. It was a forest there. And little by little, the dune disappeared, and the forest is now being attacked by erosion," he explained.

The dunes also have to cope with the tourist swarm. Here, more than a million and a half visitors trample the already fragile coastline. So, to prevent further subsidence, there are measures in place: mandatory marked paths, single-point beach entrances, and the installation of protective barriers. "It's well laid out and it also respects the site, in fact, everything is made with natural materials, so no, it doesn't bother you," said one tourist. "On the one hand, it protects the coastline, on the other hand, it prevents fires from starting, and we also enjoy a protected beach, which isn't useless with a little girl," added a vacationer. "Yes, it's necessary, it's a bit restrictive, we can't go where we want anymore, but it seems to me that it's very necessary," also said another vacationer.

Protection isn't enough. Nature sometimes needs a little extra help to revive. For the past two years, forestry agents have been collecting wild seeds from the sand to replant them on other damaged dunes, an additional way to preserve this unique environment. "We need to protect it because it already protects us from marine submersion and also from all the blowing sand. Because the sand is trapped here, it's not going to blow away onto homes or infrastructure. And then there's also the issue of biodiversity and landscape. It's still a treasure from an ecological point of view," explained Delphine Boulet, head of the ONF coastline.

Fires, storms, and overtourism are putting the dunes of the Southwest under severe strain. Saving them means protecting our best defense against erosion and rising sea levels.