Conservation: No more gloom in Dorset for smooth snake and ladybird spider

"You could say our heaths are top of the list for habitat conservation," says Andrew Nicholson, conservation officer for English Nature in Dorset. "Over the past two centuries, Dorset has lost 85 per cent of its heathland. This is particularly important in biodiversity terms, because of the climate."

Lowland heaths are some of Britain's most threatened habitats, being particularly vulnerable to development, agricultural improvements, forestry and quarrying. About half of the area covered by heathland at the turn of the century has now disappeared, and the picture in Dorset is particularly bleak.

Back in 1750, some 40,000 hectares of the county were covered in a mixture of heather and gorse. This was slowly and steadily eaten into by agriculture. (As recently as a century ago, Thomas Hardy could write about the windswept wilderness of Egdon Heath.) The loss of Dorset heathland increased dramatically in the 1930s, however, until by 1987 there were just 5,600 hectares left. As a result, many of Britain's rarest creatures, such as the smooth snake, Dartford warbler and ladybird spider were pushed to the brink of extinction. Yet in the late 1980s a concerted drive began to reverse the decline.

A variety of conservation bodies, including the Royal Society for the Protection of Birds, English Nature, the Dorset Wildlife Trust, the Herpetological Conservation Trust and Forestry Enterprise, targeted the Dorset Heathland Area. This is centred on Bourne-mouth and Poole Harbour, but stretches some 15 miles up the Avon Valley.

Although each body set its own targets (the RSPB aimed at restoring 560 hectares within 10 years, for example), the bodies co-operated closely on management schemes. Typically, the first step was to root out encroaching scrub since this out-competes the delicate heather on which a heath's wildlife depends.

In Dorset, the scrub consists principally of birch and pine saplings, bracken and rhododendron. Their removal allows heather seed which has lain in the soil for up to 60 years to germinate. And once the ground is blanketed with heather, it is difficult for invaders to re-establish themselves.

Also, because a wide range of heather ages is important to encourage diversity, some of the older growth is cut back in the autumn after the seed has set. New shoots spring up in the harvested area - vital for species such as woodlarks - while the prunings are scattered over abandoned quarries or farmland where the seed germinates. In time these, too, return to their former state.

"Ironically, healthy heathland depends on a very low level of nutrients," says Nigel Symes, RSPB Dorset Heathland project manager. "The heather and gorse can only out-compete other plants if the soil is very poor and so agricultural fertilisers are one of the worst problems we face." Because of the poor soil, fertilisers have been heavily used in the past, but fortunately, even farmland can be returned to heather with careful management. This is done by planting nutrient-hungry crops such as maize, which draw up fertiliser residues and leave the soil sufficiently depleted to give the heather and gorse a chance.

Meanwhile, Forestry Enterprise, one of the area's biggest landowners, has played an important role in co-operating with schemes where cattle are allowed to wander around forest heathland areas, helping to maximise bio-diversity with light grazing.

For anyone used to grim environmental stories about habitats vanishing forever, the results have been impressive. In just seven years the RSPB team has virtually reached its target, with 550 hectares of degraded heath restored to its original state. As a result, the woodlark population is up 30 per cent, nightjars have increased by 25 per cent and the number of Dartford warblers has doubled.

"Instead of the general doom and gloom about Dorset's heath, we've shown that conservation is possible," says Mr Nicholson. "There's a long way to go, but at least we've started to climb the ladder again by showing you can use the heaths in a sustainable way."