Don't neglect biodiversity during land regeneration
Neglected sites can often be rich havens for wildlife, harbouring rare species of birds and mammals - a fact which needs to be considered during their clean-up, says Jane ForshawA recent discussion paper by English Partnerships estimates that England has 63,400 hectares of previously developed land. And in 2005, an Environment Agency report estimated that there were between 5,000 and 20,000 contaminated land sites in England and Wales that may require regulatory intervention under Part IIA of the Environmental Protection Act.
The EA further reports that 3,500km of river and 18,000 km2 of aquifer are at risk of contamination from polluted mine waters. The need to reuse or manage these land sites in a sustainable manner has become a priority for stakeholders involved in land development. But while many brownfield sites are contaminated and require clean up, they also offer wide-ranging opportunities for wildlife.
One of the main reasons for their richness is their neglect. The Avenue at Wingerworth, near Chesterfield was a state-of-the-art coking works in 1956, and is now subject to one of the biggest clean-ups in Europe, treating substances like toxic coal tars. Yet despite the sites' industrial heritage, flora and fauna at the Avenue is rich and varied.
Specialist surveyors have identified several interesting species along the River Rother floodplain including national rare species. The occurrence of such species - which include southern marsh orchids, barn owls, water voles and great crested newts - is the result of a long period of minimal human disturbance. Detailed plans have since been drawn up to protect the species and minimise any disruption while safety and remediation works are being undertaken.
At a strategic regional level, advantage for wildlife can be taken from the coverage provided by the network of brownfield sites. The Black Country has a landscape abundant in wildlife-rich habitats. Otters, peregrines and crested newts find their homes among the region's canals and brownfield sites.
The local Wildlife Trust for Birmingham and the Black Country is now working with councils to help stitch together those patches. The centerpiece of the plan is a green bridge linking Walsall Arboretum to a network of footpaths and urban forests. By creating a swath of green space running through the heart of the Black Country, the trust aims to boost biodiversity and allow urban communities to build a closer relationship with nature.
Pollution powers biodiversity
In other instances it is the actual pollution that has provided a habitat for biodiversity. At Cwm Ystwyth in Wales, the lead mine has zinc-rich pollution - as a result, heavy metal tolerant species of lichen have developed on the spoil heaps and plants have grown on the river gravels, creating a site of special scientific interest (SSSI). If the pollution is cleaned up, the biodiversity would disappear. Yet it is this pollution that could cause the river in this watershed to fail its requirements under the Water Framework Directive.
On the policy front, the Department of Communities & Local Government is encouraging councils to take account of biodiversity within their local development frameworks. Planning policy statement 9 (PPS9) also requires that planning decisions should aim to prevent harm to biodiversity. Measures are being encouraged so that brownfield land in floodplain areas is retained for flood storage, amenity and wildlife space. It is likely that the issue of PPS 25 will aid this.
The contaminated land organisation CL:AIRE is helping to accelerate the uptake of remediation technologies on contaminated sites. Over the past three years, CL:AIRE has supported SUBR:IM - a programme of research looking at sustainable regeneration of brownfield sites. Work highlights how urban greening can improve biodiversity including the role that trees can play in locking up residual contamination in the soil, thereby reducing the leaching to surface and groundwaters.