Yesterday nature conservationists from around the country gathered in Birkenhead town hall to discuss the phenomenon and how to make the most of those unlikely green sites. Today they will visit four of them, scattered around post-industrial Merseyside.
Those wildlife-rich landscapes, which cover hundreds of square miles, often look bleak and ugly from a distance. Bold Moss in St Helen's, one of the sites being visited today, is a typical specimen. A huge colliery tip on what was an ancient bog, it is criss-crossed by electricity cables and bordered by the main Liverpool to Manchester railway line.
From its grassy, breezy summit you can see for miles. But what dominate the view are another as yet unreclaimed and completely black tip, a big power station, the town's sprawling glass works and a troubled, high-unemployment council estate known as Cement City because of its prefabricated concrete homes.
Bold Moss is home to hares and foxes and water voles, snipe and owls and sparrow hawks. All kinds of vegetation are found in its different habitats: sphagnum moss, reeds and rushes on the bog which still survives at its edges, patches of heather and grass on top, groves of willow, birch and aspen trees.
A charitable trust has been working with local people to maximise the value of Bold Moss's 55 hectares to wildlife and residents over the past five years. Some 40,000 trees have been planted and pounds 1.5m of European Union and government grants spent.
A still larger derelict area adjoining Bold Moss is to be restored over the next two years with lottery money. Close up, it is an interesting and beautiful place to walk.
So it is increasingly important to local people, many of whom have not worked since the closure of the local pit and steelworks, years ago. Adults stroll, children play, youths scramble their dirt bikes on the track specially built in a hollow and, unfortunately, elsewhere on Bold Moss.
The theme of the conference, organised by the wildlife trusts, a nation- wide network of local conservation charities, was to maximise the benefit of such sites to both people and wildlife and to learn from the mistakes of the past.
Until quite recently councils and developers would simply bulldoze such sites into flat plateaux, cover them with lots of top soil and grow grass and a few, thinly scattered saplings. In going for this easy option they eradicated interesting and unusual plants which had managed to colonise the area and instead created a deeply boring recreation ground.
John Box, an ecologist with a land reclamation consultancy, told the conference there were four golden rules for such sites:
Talk to local people to find out what they wanted;
Keep some abandoned structures such as old factory chimneys. They reminded people of the past and provided specialist habitats, such as nesting places for owls;
Let nature take its course on at least some of the site, because that would allow unusual groups of plants and animals to form naturally;
Create a bumpy landscape of slopes, valleys and hollows. That provides a greater variety of habitats and therefore species. And adults preferred strolling through hilly, varied terrain rather than a flat field while children had fun cycling in it.
"The reason you get rarer plants on these sites is because they are so stressful for vegetation," Mr Box said. "They can be very acid, or contain toxic metals. They are often dry and they are poor in nutrients."
He cited a recent survey covering six typical English counties. In that total area just over a quarter of all the government-designated sites of special scientific interest, chosen for their wildlife, were represented by old mineral workings and other industrial sites. About a fifth of the counties' nature reserves were on such sites.
But across Britain, those rich post-industrial habitats and their species are also threatened. The Government and local councils are determined that as many as possible of the 4 million or so homes to be built in Britain over the next 20 years will go on such "brownfield" sites rather than in the open countryside.
And some of the local residents seem to hate nature. At Bold Moss two swans were shot dead with air rifles this summer. Children have taken baby owls and set fire to some areas.Reuse content