History
As with many of Southern England's chalk hills, Portsdown Hill has been a site of human occupation from Prehistoric times. Neolithic, Bronze Age, Iron Age and Saxon burial sites have been found, along with features such as ancient track ways and enclosures, (see fig 2).
About 10,000 years ago the last ice age ended and with the warming climate, forest spread northwards replacing stunted cold-tolerant tundra vegetation. It is thought that Neolithic cultures (from 8000 years ago) began clearing the trees from areas where the soil could be easily cultivated - including Portsdown Hill. The farming probably involved growing arable crops as well as grazing livestock. Farming has more or less carried on ever since. From medieval times until the 1940's large flocks of sheep were kept on the hill. Agriculture was clearly important as there were several medieval villages on Portsdown. To the north the villages have either disappeared or are represented by a single farm. To the south villages have been incorporated into urban Portsmouth.
As well as farming there are other reasons why early inhabitants of the area would have preferred to occupy Portsdown Hill. Its slopes form an important defensive barrier and lookout point. It is thought that Roman, Saxon and Norman inhabitants took account of the hill's strategic value. The defensive value of the hill was recognised by the Victorians when they built the five forts along its ridge in the 1860's.
Historically the hill would have provided a safe all-year route through the area even when tracks through the surrounding countryside were impassable due to waterlogging or the fear of attack. It is likely that important routes ran the length of the hill; from early times these would have encouraged people to settle in the area.
Chalk extraction and the building of the forts have left a substantial impact on Portsdown and hidden much of the evidence of earlier cultures. Since the last war urbanisation and disturbance has increased. Large housing projects were built all along the hill's southern boundary along with MoD establishments on top of the hill. In more recent times the road traffic has increased and pylons and mobile phone aerials have appeared.
Archaeological sites on Portsdown Hill:
N - Neolithic. B - Bronze Age. I - Iron Age. S - Saxon.
Sheep grazing on Portsdown Hill in 1910. Grazing livestock have been a feature of the area for hundreds of years. Their constant nibbling maintained the open scrub-free grassland and the removal of nutrients (in the form of meat, wool and dung) kept soil fertility low. Low soil fertility in turn promotes species-richness by preventing competitive species from dominating.