ENGLISH Nature today published a disturbing report about the state of thousands of Sites of Special Scientific Interest (SSIs) scattered around the country - and made a special point of emphasising the threat to such sites in upland areas like the Yorkshire Dales.

Only half of such sites are being maintained to standards set down by the Government - and upland SSIs were at particular risk, it said.

The specific threats in these areas were over-grazing - a problem which has been under discussion for years - farm pollution and the burning of open moorland, or swaling as it is called in the Dales.

The first two problems will raise no eyebrows - changes in subsidy policy will hopefully reduce the need by hill farmers to graze more sheep than the land can properly sustain and use more chemical fertilisers.

But the criticism of swaling is likely to be controversial with the owners of grouse moors, who burn off the old heather to encourage healthy new growth in spring when newly-hatched grouse feed on heather buds and the insects they attract.

To many, swaling has been one of the key saviours of heather moorland - one of the great picture postcard assets of the Dales - for the new young heather also provides a habitat for a wide range of non-game bird wildlife.