The dunes fixed with perennial herbaceous vegetation are a type of habitat specific for the coastal area of the Danube's Delta.

The vegetation found on these dunes belongs to the wheat family. A particular species of sea crested wheat-grass can reach a height of 1 to 1, 2 m.

The type of vegetation specific for these dunes serves as an optimum habitat for various species. Here nest successfully the sand lizard and the Danubian meadow viper. In time, the fixed dunes diversify their habitats. The biotopes develop and the species find here a proper life environment.
This type of dunes can be found at Chițuc or in the Vadu area, usually behind wide beaches.