The Water Primrose, a nuisance plant

Exotic species introduced into an ecosystem, sometimes unintentionally, represent the third cause of loss of biodiversity. The Calavon river is here affected by the Water Primrose, an aquatic plant from South America. It spread in Europe in the 19th century through ornamental ponds where it was used as an ornamental species for its yellow flowers. Very invasive, it hinders the circulation of aquatic fauna, eliminates aquatic plant habitats, and can cause aquatic asphyxiation.