The Park contains a diverse range of habitats from calcareous grassland and yew woodland on Butser Hill to the coniferous and beech plantations on Holt Down and War Down.
Most of Butser Hill is designated a Site of Special Scientific Interest (SSSI) and since 1998 as a National Nature Reserve. The SSSI designation stretches beyond the boundary of the Country Park and on to neighbouring land. At 231.2 hectares this is large when compared against other lowland terrestial SSSI's and is the second largest area of calcareous grassland in Hampshire.
Within these habitats three species groups can be picked out as key features:
Butser Hill SSSI is also a Special Area of Conservation (SAC). This recognises its importance from a European perspective.
The forest blocks on Holt Down and War Down are extensive, covering over 500 hectares. Within this area are a variety of habitats ranging from ancient woodland and hazel coppice to beech and conifer plantations.
There are four water features in the Park - a concrete fire pond on Holt Down, a pond by the Visitor Centre, a concrete pond on the south slopes of Butser Hill and a reedbed adjacent to the Juniper toilets.
A number of reports covering habitat and species information within the Park are available on request.