A RARE damselfly is flourishing on parts of Dartmoor thanks to grazing of its habitat by a herd of moorland ponies.

The southern damselfly is rare and declining throughout its world range which comprises the south and west of Europe and the northern fringes of Africa.

The species was first located on Dartmoor in June 1995 by a Dartmoor National Park Authority ecologist while establishing a management agreement on a privately owned wet grassland site near Whiddon Down.

Subsequent searches over the next few years revealed a further two colonies near Gidleigh and Sourton.

Over the past 14 years, the authority has worked in partnership with landowners, commoners and other organisations to enable the survival of the globally threatened damselfly within the national park.

At the site near Whiddon Down, the damselfly was thought to be in danger of extinction when first located, as the small breeding runnels in which the larvae live were swamped with coarse vegetation.

The colony there remained on a knife's edge for the next ten years, despite much effort to control scrub growth, improve fencing and achieve better cattle grazing.

However, a breakthrough came four years ago when the authority organised some additional grazing of the site with a small herd of Dartmoor ponies.

The site has since produced bumper numbers of damselflies, helping establish the worth of Dartmoor ponies as conservation grazers.

The ponies remove even the toughest and most unpalatable grasses and rushes, opening up the runnels in which the damselfly larvae spend two years maturing before finally hatching out into the adult damselflies.

Much of the monitoring and management work that the national park has organised has been financially supported by the Environment Agency.