One of the North’s rarest butterflies is making a remarkable recovery on Teesside and it is mainly thanks to heavy industry. John Dean reports.,p> GRAYLING butterflies disappeared from most of the North- East more than a century ago, but are appearing in increasing numbers on Teesside industrial sites.

The recovery has been confirmed by ecologists from the Industry Nature Conservation Association (Inca), which is based at Wilton International, near Redcar, east Cleveland, and works with businesses to encourage wildlife on their sites.

Inca ecologist Ken Smith said: “Grayling disappeared in the North in the 1890s, and into the 1900s. Now we are seeing them recolonising more sites on Teesside.”

The reason the butterflies like such areas is because their ideal habitat is sparsely vegetated areas, which often exist on the buffer zones around factories and chemical plants.

One such example is the Lucite International Cassell site, in New Road, Billingham, where the company makes acrylic products.

Two years ago, Inca confirmed that grayling had been reported on the five-hectare grassland and wetland area between the plant and nearby houses.

Now, Inca, which is working with the company to develop a biodiversity plan for the area, says the insect has become established on the site.

Mr Smith said: “The site supports a range of butterfly species, including what we believe is a growing number of grayling.

“The reason we are seeing more grayling across Teesside is that the habitat is right for them on industrial sites.”

Other areas where the insect has been reported include the Wilton International chemical complex, Maze Park, next to Thornaby Marshalling Yards and Corus, in Redcar.

Those sightings had been sporadic over the past five years, but Inca conservation officer Robert Woods said: “More industrial sites across the Tees Valley are now starting to see grayling. Numbers are increasing. It really is a success story when it comes to industrial areas.”

Such successes have assumed a national importance, because the grayling is vanishing from its southern coastal heathland habitats.

The Inca team has recorded more than 15 other butterfly species on the Cassell site, including meadow brown, wall, small heath, ringlet and orange tip, as well as numerous species of dragonflies and moths.

Mr Woods said: “That they are there is good news because butterflies, and moths and dragonflies, are good indicators of the environmental health of an area.”

Amanda Buck, Lucite technical safety and environmental manager at the Cassell site, said: “This piece of land is disused because it was a quiet area between our operations and local residents, so that they are not disturbed by what we are doing. Why not manage it for wildlife?”