Road crossings for animals are multiplying, including far from highways

A real disaster. Several million wild animals perish each year on French roads, victims of a collision with a vehicle. Mammals, reptiles, amphibians, birds, bats, all are affected. “The most emblematic are surely the hedgehog, which rolls up into a ball when it is afraid and is therefore particularly vulnerable, as well as foxes, badgers, or large game, whose collisions are a problem for human safety”, explains Stéphanie Morelle, biodiversity project manager for the France nature environment (FNE) associative network.

But the damage is also important for less visible fauna, such as bats, salamanders or butterflies. “For some endangered species, the impact of roads can even be very strong, like the lynx and the wolf. Their first cause of death is collisions. »

Ecobridges, tunnels, benches, rope ladders…

If it is not new, the phenomenon has for several years aroused a growing awareness of the authorities. Infrastructure developments, which allow animals to continue their movements without risking their skin, are beginning to multiply. On the motorway network, a pioneer in the field, but now also on the secondary network.

“Things are moving since Nicolas Hulot’s Biodiversity Plan [2018] and the implementation of the principle “avoid, reduce, offset”​ [2020], observes Stephanie Morelle. We see a variety of devices. We are talking about ecobridges, ecoducts, tunnels, aerial bridges to force bats to fly high, benches under structures for otters and beavers, rope ladders for squirrels…”

“Amphibians seem the most threatened, their population is collapsing”

Loire-Atlantique is one of those few departments that have recently decided to tackle the problem head-on. Some 250 new infrastructure developments are thus announced by 2027 by the new socialist majority. One million euros is dedicated to them this year.

A tunnel to allow small animals to avoid the road. In Loire-Atlantique. – P.Pascal/Loire-Atlantique Department

Basically, a very precise inventory of mortality, with counting of corpses over one year, was carried out with environmental associations. The conclusion is clear. “At least 1,081 animals were killed in the 20 km sector studied. Extrapolating to the scale of the road network managed by the department, this makes more than 230,000 animal victims of collisions per year. It’s quite huge. Amphibians seem to be the most threatened, their population is collapsing,” underlines Chloé Girardot-Moitié, vice-president of the Loire-Atlantique departmental council.

Rethink maintenance, hedge trimming, waterways

Specific facilities (tunnels, artificial banks, footbridges) have therefore been devised, on a case-by-case basis, with the associations, depending on crossing habits. But the approach goes further. “We identify the areas where bats nest to review how to maintain bridges, we rethink the size of hedges so as not to disturb nesting and the species that find refuge there, we carry out work on certain bridges or locks to allow fish farming continuity… This subject must be gradually integrated throughout our infrastructures,” says Chloé Girardot-Moitié.

A walkway under a bridge, especially for the European otter, a protected species.  Here in Loire-Atlantique.
A walkway under a bridge, especially for the European otter, a protected species. Here in Loire-Atlantique. – P.Pascal/Loire-Atlantique Department

Wishing to “disseminate good practices”, Loire-Atlantique has also published guides for municipalities, which are even eligible for subsidies if they are part of the process.

“All of this is going in the right direction,” rejoices the biodiversity mission manager of France nature environnement. Afterwards, we must not forget the monitoring and evaluation of these systems. Sandrine Morelle insists. “The eco-bridges, for example, we know that there are places where it doesn’t work. Either because the location is ultimately not good, or because the predators adapt their behavior while waiting for the mammals to come out of the bridge to eat them. There is not a single answer but several solutions. And it is necessary to adapt. »

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