A SURVEY is taking place on Salisbury Plain training area to help protect the rare fairy shrimp population.

The project is attempting to establish the distribution of the fairy shrimp (Chirocephalus diaphanous) and identify areas of suitable habitat.

They have now been discovered on the east of the Plain, with previous records only indicating existence on the west.

The mysterious fairy shrimp is a translucent crustacean and occupies temporary pools.

It is protected under Schedule 5 of the Wildlife and Countryside Act 1981 and classified as vulnerable in the British Red Data Book.

The species are listed as a feature of the Salisbury Plain SSSI (Sites of Special and Scientific Interest).

Salisbury Plain provides excellent habitat for the fairy shrimp, as military vehicles create a complex system of temporary pools, with fairy shrimp eggs transported between them on the tracks of armoured vehicles.

Historically, fairy shrimp eggs were dispersed by grazing cattle and inhabited small pools created after livestock poaching.

The eggs lie dormant when the puddle dries out and then hatch when wet conditions return.

They can survive in their dormant state for up to 15 years. The species feed on organic particles and microscopic animals and have 11 pairs of legs.

The fairy shrimp constantly swims on its back and has a high tolerance of different water chemistry and temperature; it has even been recorded under the ice in freezing conditions.

Nationally, the creature is becoming rarer as temporary pools and dew ponds are filled in and pasture reverts to scrub and woodland.

The fairy shrimp cannot co-exist with fish species - therefore it inhabits short-lived puddles and ruts.

As well as Salisbury Plain, small populations are also supported in the New Forest and Dartmoor national parks.

Oliver Howells, an ecologist working for Defence Estates, said: "We are certain that military activity is beneficial to fairy shrimp as it creates localised pockets of disturbance where temporary ponds are formed.

"This study will provide a more accurate picture of their distribution on Salisbury Plain and help us better understand the link with military training."