Iron Age hillforts in Dorset are to be given a new lease of life.

The National Trust has been awarded £800,000 towards restoring the 13 sites in Dorset and Wiltshire.

The sites include Pilsdon Pen, Eggardon Hill, Coney's Castle, Lambert's Castle and Lewesdon in west Dorset, and Hambledon Hill, Hod Hill and Badbury Rings near Blandford,

The monuments all date from more than 2,000 years ago and, in addition to their archaeology, they have diverse fragile habitats, which are homes to threatened butterfly species including the brilliantly coloured Adonis blue, the small Duke of Burgundy and the orange, yellow and brown chequered marsh fritillary.

The defences of the Iron Age Hambledon can still be seen today and, together with its three ramparts encircling the hill, is one of the most impressive archaeological earthworks in southern England.

The work to be carried out ranges from erosion repairs to paths and ramparts to improving fencing so that cattle can graze in the summer and sheep during the winter.

Volunteers will help with ragwort removal in the summer months, and there will be green hay spreading at some sites to enhance the diversity of wildflower populations.

National Trust ranger Clive Whitbourn said: "The hillforts protrude mysteriously from the landscape, offering stunning views across the Dorset countryside.

"From Badbury Rings you can see the Isle of Wight, and from Eggardon Hill, Pilsdon Pen, Lambert's Castle and Coney's Castle there are views of Lyme Bay.

"They are thousands of years old and reveal much about the way of life of our ancestors.

"Due to scrub encroachment and erosion, urgent action is needed to protect them for the future for everyone.

"The work we will be doing together with a small army of volunteers will include scrub removal, fencing and improving access to visitors.

"This will result in better care of chalk grassland habitat and help attract more wildlife.

"This will include wildflowers like pyramidal orchid and cowslip, birds like skylark and kestrel, or mammals like brown hare – as well as butterflies – helping us meet our ambitions for nature.

"Archaeological features including long barrows and round barrows will be better protected when the threat of root and scrub damage has been removed."

The funding has come from Postcode Earth Trust, raised by players of People’s Postcode Lottery.

Laura Chow, Head of Charities at People’s Postcode Lottery said: "The Wessex Habitats and Hillforts project will preserve not only part of our heritage but create the ideal habitat for attracting butterflies which we hope will then increase the number of rare butterflies.’