Each natural region of the Aude has its own particular landscape. In the east, lagoons or coastal lakes form a barrier between land and sea. These were formed by accumulated sediments brought down by the rivers Aude, Orb and Hérault. There are many such lakes of brackish water. This environment is demanding for flora and fauna, as it suffers from the rigours of sea, sun, dryness and floods. Halophile (i.e., salt-loving) plants grow there. The area is also noted for the pink flamingo and white stilt.