By Jemima Laing
The ponies are on loan from a Dartmoor Commoner
Dartmoor ponies are unwittingly helping to protect a rare fly on Dartmoor - thanks to their less than discerning eating habits.
Because ponies are much less fussy eaters than sheep or cattle they are ideal for grazing an area inhabited by the rare bog hoverfly.
The area behind Dartmoor National Park Authority's (DNPA) Haytor Information Centre is a wet heath.
It is home to the fly - which is now only found on Dartmoor in the UK.
If left unmanaged, the habitat would eventually scrub over and turn into woodland, making it far less attractive to the insects and plants that live there.
As well as the rare fly, the site is home to bell heather, bog mosses, and the bog asphodel.
Dartmoor is the only place in the UK the fly is found
"We are using native type ponies to graze the heath to maintain the existing community," said Naomi Barker, DNPA ecologist.
"The ponies are an excellent habitat management tool.
"They will nibble at the bigger tussocks of rush and grass and therefore give the smaller plants, such as the mosses and bog asphodel, a chance to persist.
"Their small hooves result in minimal damage to the wet ground."
The extensive grazing carried out on Dartmoor's uplands over thousands of years has resulted in a special relationship between open grazed habitats and rare and charismatic species.
The ponies live out on the moor all year round and spend most of the time in small herds of mares, with one adult stallion and young ponies.
The DNPA has an agreement with a Dartmoor Commoner, who provides three herds of native Dartmoor ponies to carry out conservation grazing on sites of particular ecological interest.