The varied geology and rich woodland heritage of the Wrekin Forest has long made the area a focal point for commercial exploitation. As long ago as the Thirteenth Century, limestone (a key ingredient in iron production) was being extracted from beneath its soils — a process that sped-up dramatically from the late 1600s onwards during the Industrialisation of east Shropshire.
In that epoch-defining era the trees of the Wrekin Forest were coppiced extensively, providing pit props for mineshafts and charcoal used in the extraction of iron ore. The fragmentary remnants of the burning stages associated with this process (known locally as ‘cockarths’) litter the slopes of The Wrekin, along with numerous old coppice trees, and abandoned bell pits long since returned to the fabric of the ancient woodland landscape. The scars of recent activity (which has concentrated on quarrying the forest’s mineral reserves) are far more apparent. Rather than being cause for consternation, however, these brownfield locations offer unique habitat for countless plants, insects and animals, the like of which is increasingly scarce elsewhere.
The term ‘brownfield’ is often used pejoratively to describe land deemed more suitable for new housing than wildlife. While there is admittedly little value in an acre of hard standing, the reality is often more nuanced and many of our best sites offer a range of closely linked habitat features impossible to replicate in open countryside. The value of these post-industrial oases is such that they have been referred to as ‘Britain’s rainforests’ but what exactly constitutes a ‘brownfield’? Put simply, it is a piece of land (measuring at least 0.25 hectares — about a quarter of a football pitch) that has been altered by human activity. This definition can cover a multitude of situations but, in the case of the Wrekin Forest, what we’re really talking about are old quarries. Despite bearing signs of our influence, the historic localities associated with east Shropshire’s coal and iron industries are now largely indistinct from the area’s woodlands, sharing much of their character and attracting the same range of flora and fauna.
Good brownfield sites contain combinations of different habitat, such as heath, grassland, scrub and open water. They not only replicate features that are declining in the wider countryside but, because they exist close together, benefit species (including many of our pollinating insects) that need a range of interlinked conditions to complete their lifecycles. The presence of substrates introduced by humankind, such as sand and gravel, and of soils very low in nutrient value, tend to inhibit plants and grasses that thrive on agricultural land where fertilisers are applied regularly, allowing less dominant species to gain a foothold. The pattern of exploitation within the site itself can also play a major role in creating a unique environment, modelling the contours of the land and influencing the way water drains from it — both key determinants in attracting the widest range of species possible.
‘Open mosaic habitat’ is a phrase used to describe the ecological smorgasbord that characterises a good brownfield site. As you may already have guessed, what is included in the selection on offer can vary greatly from location to location, and often appearing in unusual combinations: rough grassland, patches of bare ground and gravel, rubble piles, heathland, bramble scrub, seasonal and permanent pools are all typical features of disturbed landscapes. These small, connected spaces enable a huge range of creatures to co-exist in a way they couldn’t elsewhere and a growing number of native species are now strongly associated with, or largely confined to, brownfield sites.
In terms of a good starting place for your own investigations, an inspection of the local ground flora is highly recommended. Ruderals are plants that colonise disturbed ground and are the first to establish themselves, thriving where soil is of a poor quality or in short supply. Generally tall in stature, species such as Wild Carrot (Daucus carota) and Common Toadflax (Linaria vulgaris) are typical pioneering examples. Grasses can take several years to become established on brownfield sites but may eventually form flower-rich havens for pollinating insects. Here, species such as Meadow Buttercup (Ranunculus acris), Ribwort Plantain (Plantago lanceolata) and Bird’s-foot Trefoil (Lotus corniculatus) are commonplace. However, if you discover low-growing dwarf shrubs such as Common Heather (Calluna vulgaris), Bilberry (Vaccinium myrtillus) and Wavy-hair grass (Deschampsia flexuosa), the chances are you have stepped onto some burgeoning heathland.
In large landscapes like the Wrekin Forest, brownfields can benefit a wide range of specialist plants and insects on the edges of their range, providing stepping-stones into the wider landscape. Locally, some of the best sites are the former stone quarries beneath The Ercall, which were abandoned in the mid-1980s. Nowadays, rare flower-rich acid grassland covers part of the quarry floor, providing habitat for plants and butterflies alike, including the Midlands rarity Dingy Skipper (Erynnis tages) and Green Hairstreak (Callophris rubi), which lays its eggs in Bird’s-foot Trefoil and Bilberry. The bare ledges and rock faces of the quarries also provide good basking for insects and reptiles (including Slow Worm and Common Lizard) but a special mention should be given to the locality’s mosses and liverworts, of which The Ercall has a renowned collection. Brownfields are particularly good for plants that thrive in soils with a low nutrient content and these ‘stress tolerant’ species (which, together with hornworts, are known as Bryophytes) can envelop large areas of ground, providing a growing agent for other plants, and cover for predatory insects and amphibians.
The Ercall is far from the only brownfield site of note in the Wrekin Forest. Further east on the other side of Limekiln Wood lies Maddocks Hill, which fell victim to the same brutalising forces of extraction as The Ercall. It is also recovering well from this intrusion but the vigorous growth of woodland and scrub here is beginning to create a shadier, more uniform and less interesting landscape. Beyond the woodlands themselves, the recent scars of open cast mining are only too apparent at Huntington, which offers an enticing prospect of brownfield ecology in the making. For mature examples of what can emerge in just such a situation, the rough grasslands and pools of Shropshire Wildlife Trust’s nearby Smalley Hill reserve, and the Benchwalks around Little Wenlock are worthy examples. Sadly, one location that is not so accessible is Devil’s Dingle, a former Pulverised Fuel Ash (PFA) dump for Ironbridge Power Station situated above the Severn floodplain at Buildwas. It now forms a grassland and wetland oasis for all manner of avian visitors en route through the Severn Valley but has recently changed ownership and is strictly off limits to casual visitors. You have been warned!