Roughly estimated, grasslands in Flanders take up 26700 - 42900 ha, and as such they are the most prevalent biotope. The large majority of those grasslands are poor in species, highly fertilized, often sown agricultural fields. A large number of grassland types is rare.
Grassland's biological richness is highly determined by surrounding factors. A large number of fauna-elements that spend (part of) their life cycle in grasslands are highly dependent on small landscape elements in or surrounding it, like (non)-rising structures and mosaic-elements of other biotopes (e.g. swap or dune) and their interactions. Molinia grassland, calcareous grassland and calcareous dune grasslands are (very) rich in red list plant species. Dry and wet nutrient-poor semi-grasslands are of great importance for red list butterflies.