ENS - La Prée des Cosses

The Prée des Cosse is the largest group of flooded wet meadows in the Sèvre Nantaise valley. It is criss-crossed by its ancient branch, commonly known as "la vieille Sèvre", and dotted with wet depressions, remnants of ancient meanders, among other features. The site is distinguished by its exceptional biodiversity, resulting from the variety of habitats that make it up.
The various habitats complement each other well, with wet meadows, riparian forests, megaphorbia, poplar plantations, the Sèvre Nantaise oxbow and the Sèvre River, giving the site a bocagère identity. The plots of land located between the dead-end arm and the current bed of the Sèvre river are rich in flora and fauna.
At La Prée des Cosses, up to 10,000 plants of guinea fritillary have been recorded.
As its natural habitat is threatened, harvesting is prohibited.