Long-established habitats usually support a much more diverse range of wildlife than those of more recent origin and the more important semi-natural habitats on Mendip have developed as a consequence of a complex interaction of underlying geology, soils, aspect, climate, and a range of other factors. The modern-day Mendip landscape also supports extensive areas of intensively-managed grazing pasture, particularly on the deep and fertile soils of the plateau. Agricultural 'improvement' has encouraged application of fertilisers and re-seeding with rye-grass and other palatable grasses, giving such swards a characteristic vivid green colour throughout the year. However, such grasslands have lost most of their original character and contribute little to the biodiversity of the area.
Many different habitats can be found in the Mendip Hills, but in the context of publicly accessible sites, three are especially characteristic: