 Hengistbury Head forms part of the Christchurch Harbour Site of Special Scientific Interest (SSSI), and in May 1990 was declared a Local Nature Reserve. The Head supports 500 plant species (a quarter of the national flora), including eight red data book species, 14 nationally scarce, and 39 locally rare species. The main nature reserve area faces Christchurch Harbour, and is contiguous with the reed beds of Wick Fields. The Head contains a large variety of habitats from the heathland on Warren Hill to freshwater ponds, sand dunes, and salt marshes. The woodland (known as Withybed Wood) is home to English oak and silver birch amongst many other trees, and is of particular interest, as it is the only such area to be shown on an 1811 Ordnance Survey map of the Bournemouth / Christchurch area. In 2002, cattle-grazing commenced in a field near the new visitor centre known as "Barn Field". This, combined with gorse eradication, has assisted in the restoration of this habitat to its ancient character.
