The Lower Normandy 700 km coastline presents highly contrasting morphologies and plant communities adapted to salty environments. The maritime cakilier, also known as maritime shellfish or sea rocket (Cakile maritima), and sand grass (Agropyrum junceum) are found there, and constitute the first obstacle for the sand blown onto the beach by the wind. Their disappearing would jeopardise the entire dune area, which cannot stand direct contact with the sea. The sand rye (Leymus arenarius), sometimes also called sea rye or big oyat, shares the same habitat. All these plants are interdependent and help to keep the dunes in place.