PURPLE heather is returning to a Dales hill farm - thanks to Highland cattle.

On Saturday, James Mawle and his son, David, welcomed the Highland Cattle Society and a wide range of farming and environmental organisations to Coverhead Farm, in Coverdale.

The Mawles bought the farm in 1983 and have 5,000 acres of shooting and grazing rights. They ran it as a hill farm with 2,400 ewes and 75 blue-grey cattle until 1999, when they joined the Countryside Stewardship Scheme. As part of that agreement, they cut stocking numbers to the maximum allowed - 1,250 ewes and 20 cattle.

David Mawle explained that stewardship guaranteed an income in very turbulent times for sheep prices.

One of the main effects from reducing livestock was that, where the cattle grazed, heather returned, but in the sheep only areas, it did not. "It got me thinking and I hunted round for an animal that would eat the grass off," said David Mawle.

A magazine article put him on to the Highland and in February last year the first 20 arrived. The Mawles then dropped sheep numbers to make room for more cattle.

"We now have 75 Highlanders and 750 sheep," said Mr Mawle. "I personally decided they were a sensible money-making exercise and, compared to sheep, had some serious advantages."

The farm is ring-fenced with no shared grazing and the family has taken the opportunity to experiment, forming a number of compartments where different grazing regimes are carried out to see what works best.

Britain has 75pc of the world's remaining heather moorland but it is a habitat in severe decline in this country. About 200,000 acres have been lost since 1945 through forestry, overgrazing by sheep, spread of bracken and general neglect. Studies in Scotland have shown that careful grazing by Highland cattle complements other measures to halt the decline.

Renowned for their hardiness and docility, the cattle happily graze the extensive rough grazing and upland pasture where sheep are typically found but, unlike sheep, they prefer the rough grasses, giving the heather and bilberry time to grow.

David Newborn of the Game Conservancy Trust said that, historically, more cattle grazed such upland pastures than sheep; that position was slowly returning.

He said work in Scotland had looked at the role of Highland cows in heather regeneration. "We are starting to get signs that the heather does regenerate better when we are grazing cattle for some period rather than just sheep," he said. "A combination of the two is probably the best way forward.

"When we go into heather regeneration, we get a big flush of grass so we need ways of controlling it and the grazing cattle technique is what we look for to give the heather time to get re-established."

The red grouse diet is 80pc heather, with young heather having the highest nutrients.

Heather seeds need light, which the grass and rough pasture blocks out, but seeds can lie dormant for 70 to 80 years.

Mr Newborn did warn that the cattle did need careful management.

One project in Northumberland had seen a group of suckler cattle - not Highland - put out straight from the sheds in May. "We had wanted them moved in June, but they were turned straight out and went wild, and in quite big mobs, which did not help," he said.

It was estimated that 20pc of the red grouse nests on the moor were trampled, and two hens trampled and killed.

Rita Mercer of Defra's Rural Development Service, who helped develop Mr Mawle's CSS agreement, said: "Coverdale is typical of much of the upland moorland in the Pennines, where heavy grazing by sheep has damaged the traditional heather cover.

"We would normally advise farmers to exclude stock to allow the heather to grow, but this experiment suggests that Highland cattle really are a novel tool which can be used to manage rank grasses which would normally overpower the heather.

"The cattle can act as active land managers, leaving the farmers time to tackle other environmental work."

James Mawle, a Moorland Association committee member, said the farm's policy was to diversify from dependence on hill sheep. "Highland cattle fit the bill by eating the under-utilised coarse upland grasses while improving the ground," he said. "The payments from the ten-year Countryside Stewardship Scheme agreement give us an income while these changes take effect.

"By 2009, we aim to have three sustainable, economically viable and mutually beneficial enterprises: Highland cattle, sheep and red grouse shooting. The bonus is that heather coverage, landscape value and biodiversity will all increase."

A valuable commercial benefit is that Highland cattle produce high quality beef. The Highland Cattle Society has developed a sales network for the meat which emphasises its quality and traceability.