Metropolitan France now has 338 national (RNN) or regional (RNR) nature reserves, covering more than 300,000 hectares thus preserved. Defined by the Environment Code, this status concerns natural environments of heritage importance and which should be protected from any artificial intervention likely to degrade them.
If it is possible to limit in these protected areas the alterations linked to the exploitation of resources, the artificialization of the soil, hunting or pollution of various origins, in particular agricultural, a new peril without borders threatens biodiversity. fragile that finds refuge there: global warming.
More than 65,000 hectares of forests went up in smoke during the summer of 2022 while the rainfall deficit has never been so severe for nearly sixty years. The LPO (League for the Protection of Birds), which manages 8% of French nature reserves, studied the impact of this episode of drought on the fauna and flora in ten of them, in Charente-Maritime. and in Vendée.
The survey shows that the early and prolonged drying of ditches and wetlands has heavily affected the wildlife species that normally thrive there. The excess salinity disrupted the germination of autochthonous plants while favoring the expression of an unusual flora. Very dependent on the presence of fresh water, batrachians, insects and fish have paid a heavy price, as well as their main predators: birds.
Two endangered species, a small toad, the cultriped pelobate, and a dragonfly, the leste with large stigma, have not reproduced in the national nature reserve (RNN) of Moëze-Oléron, where they nevertheless had their habits. In the RNN of the Müllembourg marshes, located on the island of Noirmoutier, the overheating of the basins connected to salt water has led to the death of eels, another species in decline.
The black tern, classified as endangered on the red list of breeding birds in France, no longer nested in the whole of the Marais poitevin last year. The numbers of migratory waterbirds observed last August were almost twenty times lower than the average for the previous five years in the Marais de la Vacherie regional nature reserve (RNR) and the Saint-Denis RNN. -du-Payre.
The only good news remains very insufficient to rejoice: the creeping water primrose, a South American aquatic plant that has invaded many European marshes, has also suffered from the water shortage.
With ever higher and earlier maximum temperatures and ever rarer rainfall, 2023 promises to be even drier than 2022. This escalation of drought could permanently compromise the survival of many fragile species.
Not to mention the rise in the level of the oceans, which risks amputating several coastal natural reserves that the State gives up defending, resigned to letting the salt water cover them little by little. The sea seems to want to take back the territories that man has won over the centuries at the cost of immense development efforts. The RNNs of Lilleau des Niges on the Ile de Ré and of Moëze-Oléron are already dealing with this problem.
To halt the collapse of biodiversity, it is therefore essential that the public authorities now integrate the climate factor into the creation, extension or relocation of nature reserves, and strengthen the protection measures there. If climate change is now reaching nature right to its heart, where it is most resilient, it means that the situation everywhere else is already looking like a disaster.