Nature’s Quick Comeback: Volunteers Revive Dried Mountain Ponds After Drought

Plateau de la Molière (Vercors), reportage

Armed with shovels, picks, a few pruning shears, bright orange gloves, and tall rubber boots, a group of about ten individuals is gearing up for a special kind of outdoor project on this sunny September morning in the Vercors. Their mission is to restore the Robertière pond, located at the heart of the sensitive natural area of Molière-Sornin and within a Natura 2000 site.

“We’re going to clear out the overgrowth and do some digging to reopen the area to aquatic species,” explains Jean-Baptiste Decotte, team manager for ecosystems and renaturation at the League for the Protection of Birds (LPO), which is co-organizing the project with the Vercors Regional Nature Park.

Due to drought and heatwave episodes, the Robertière pond has gradually dried up over the past few years. As the water level dropped, vegetation, particularly sedges which thrive in moist soils, dominated the space and accumulated dead plant matter, suffocating the pond’s natural processes. The species that typically inhabit these surroundings, such as green tree frogs, alpine newts, and several species of dragonflies, which rely on the pond for reproduction and laying eggs, have experienced disrupted life cycles recently.

Equipped with a shovel or pick, today’s volunteers—including local residents, park members, and LPO staff—venture into the pond. They need to pull out the sedges, reaching deep into the mud for the roots. The task is physically demanding, and progress is slow in the pond, which stretches 20 meters long and 30 meters wide.

“We’re making headway bit by bit,” comments Christian, a local volunteer, his face flushed from the effort. “Some people pay for mud baths,” jokes Alan, a seasonal park ranger, his face and arms smeared with mud.

As they remove the vegetation, small alpine newt tadpoles and dragonfly larvae start to appear in the few centimeters of water at the bottom of the pond. “It’s late for the newts. It could be a result of climate change. They probably delayed spawning because of the drought, waiting for the water to return,” notes Jean-Baptiste Decotte.

Early autumn is typically the best time for such a project, to minimize damage as most species have already laid their eggs and left the pond. “Any project causes some disturbance, but we believe the benefits are significant,” explains Nathalie Lécrivain, mission manager for the sensitive natural area of Molière-Sornin.

“What’s impressive is how quickly life returns to the ponds,” says Jean-Baptiste Decotte. “Given the area covered, the energy expended, and the gains for biodiversity, few conservation actions are as effective. Plus, these projects aren’t very costly; most of the expense is in the planning.”

The project cost about 3,000 euros, with 2,000 euros funded under the sensitive natural area of Molière-Sornin and 1,000 euros under the Natura 2000 designation.

Later in the day, a mechanical excavator takes over from the volunteers to remove more aquatic vegetation. As the pond becomes clearer, the volunteers focus on collecting as many larvae and tadpoles as possible. These young insects and amphibians are temporarily housed in barrels, and will be returned to the water once the project is complete to minimize disturbance.

“You always need to have wet hands when handling them, as they are sensitive to light,” advises Flora, a civil service volunteer for the LPO, as she moves a newt tadpole in her hands.

“This pond has always had an ecological purpose,” shares Nathalie Lécrivain. Originating in the 1990s from a smaller natural pond by the warden of the Molière lodge, its role is to act as a refuge for biodiversity, especially as wetlands are scarce in the Vercors massif. “The area is karstic, so water drains quickly. If wetlands form, they are often temporary, drying up naturally each year,” she explains. In the ecosystem of the Plateau de la Molière, the Robertière pond serves as an oasis for biodiversity.

Through a dedicated program, Alpi’mares, the LPO is restoring more and more high-altitude ponds like this one. “Several factors contribute to a pond drying up: human activities, errors in design at the time of creation, and climate change. In summer, there can be periods of a month and a half, even two months without rain. The ponds are attractive in spring when they are full of water, but they quickly dry out and become death traps for the biodiversity that has settled inside,” explains Jean-Baptiste Decotte.

In France, due to increasing urbanization, intensive agriculture, and various human interventions, half of the wetlands were lost between the 1960s and 1990s, according to the French Office for Biodiversity.

“In the Vercors, they are in rather poor conservation status, poorly cataloged and thus poorly protected,” says Chrystelle Caton, mission manager for the Vercors Regional Nature Park on the Municipal Biodiversity Atlas project, an initiative cataloging fauna and flora. “It is all the more important to preserve them as they help maintain a reservoir of biodiversity that is part of a whole, a food chain that has a broader impact.”

Once the pond is restored, the autumn rains and the precipitation of the cold season should gradually fill it, allowing a resurgence of biodiversity in the spring. “They’re predicting rain this week,” notes Nathalie Lécrivain, “it should heal soon.”