EXTRA funding means environmentalists can treble their efforts to monitor one of Britain's rarest dragonflies in Purbeck.

The beautiful southern damselfly is a bright electric blue but only six colonies remain in the Purbeck area of Dorset -one of its last strongholds in the south west of England.

Several organisations including English Nature, the Royal Society for the Protection of Birds, the Ministry of Defence and National Trust have joined forces with the Environment Agency to halt its decline and help it make a comeback.

A programme of conservation measures is being carried out to improve conditions for the damselfly including scrub clearance to keep streams open.

Clay extraction company Imerys International has now decided to increase its funding from £500 to £800 a year which means three sites in Purbeck can now be monitored instead of just one.

Emma Rothero, of the Environment Agency, said: "The project's aim is to ensure that our conservation work results in the expected increase in damselfly numbers.

"Site managers will be able to pick up problems at an early stage if the populations show signs of decline so this work is crucial for the long term survival of the damselflies."

In Britain the southern damselfly is living on the extreme north-western fringe of its European range. Its two main strongholds are in the New Forest and the Presceli Mountains but smaller colonies exist in Dorset, Devon, the Gower and Anglesey.

Dorset heathlands are vital wildlife habitats supporting 31 out of Britain's 38 species of dragonfly.

In the 1800s heathland covered most of south-east Dorset stretching from Dorchester to the New Forest but 86 per cent has been lost since then and there are now nine blocks broken into 150 fragments.