Biodiversity case studies: The value of restoring nature to brownfield sites

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BIODIVERSITY

The value of restoring nature to brownfield sites

By Laura Edgar

It has been a kind of mantra for a while now: prioritise brownfield land for development. Protect green spaces, greenfield and the green belt.

Successive Conservative governments have all prioritised brownfield land for development. Back in 2014, under David Cameron, then chancellor George Osborne announced plans to allow developers to build on almost all brownfield sites, with a wider aim to encourage the building of up to 200,000 homes on sites designated as brownfield that are not in use.

In 2016, then communities secretary Greg Clark, launched a pilot for brownfield registers, which was extended to all English councils in 2017.

Such land is deemed an eyesore, but it can offer more biodiversity than some greenfield and green belt sites.

A study published in January this year found that former mining areas in northern England had become a refuge for one of Britain’s fastest-declining resident bird species, the willow tit. Numbers have plummeted by 92 per cent since the 1970s. The RSPB classifies its conservation status as red, meaning that urgent action is needed to address the decline.

But according to the UK Centre for Ecology and Hydrology, willow tits have over the past 50 years retreated to former coal mining areas from Cheshire to Northumberland.

Wilding of a Post-industrial Site Provides a Habitat Refuge for an Endangered Woodland Songbird, the British Willow Tit Poecile montanus kleinschmidti considered why willow tits fare well at these sites.

Willow tits can now be found at former coal mining areas from Cheshire to Northumberland

Over three years, Dr Richard Broughton worked with Marta Maziarz from the Polish Academy of Sciences and local citizen scientist Wayne Parry to conduct surveys at former mining sites on the Wigan Flashes (see box) and Amberswood Common, which have been restored to wetlands, woodlands and green spaces.

Parry monitored more than 30 nests each year to find out the number of pairs and their breeding success. The study found that a pair of willow tits needs seven hectares, a “large” territory for small birds. Broughton says: “They spend their entire lives there, so it needs to provide everything they need.”

Although the study focused on the Wigan Flashes and Amberswood Common, the findings can be translated to other areas with old coalfields where willow tits are found.

The Wigan Flashes and Amberswood Common are a mosaic of wetland, grassland, marsh and woodland, with shallow lakes and pools formed by mining subsidence. Because the area was worked until the 1990s, the colonising woodland is relatively young. Broughton told The Planner this gives willow tits an edge before it matures and becomes more suitable for their competitors – blue tits and great tits.

What makes brownfield land a suitable home for wildlife

Broughton highlights that brownfield land is often poorly understood, meaning it is not always known what wildlife lives there. The longer a site has been left undisturbed, the more wildlife it tends to support. “Sites with subsidence issues, which regularly flood, are best "BROWNFIELDS ARE insulated from future OFTEN SOME OF OUR development and do have LAST REMAINING the best prospects for HAVENS FOR NATURE long-term rewilding.” IN AN INCREASINGLY Each brownfield site MANAGED LANDSCAPE is different too, says Ben - WHETHER URBAN OR Kite, managing director THE COUNTRYSIDE“ – at Ecological Planning JAMIE ROBINS & Research (EPR) Ltd.

Amberswood Common is a terrain of wetland, grassland, marsh and woodland that is home to various types of tit

Abandoned industrial areas contain overgrown developed land with lots of concrete, which is alkaline. This creates the conditions required for wildflowers of calcareous grasslands to flourish. In contrast, bare ground areas will retain the naturally acidic or mesotrophic conditions of the London Basin, favouring plants of these habitats.

This results in a diverse floral assemblage, leading to foraging areas for invertebrates and pollinators, which in turn can support rare birds like the black redstart, an important species in London, says Kite, and spotted in this news editor’s tiny garden in the southeast of the city earlier this year.

“In short, abandonment or dereliction can mean that nature is often given the space needed to thrive in relatively undisturbed conditions, and the combination of built human form and resurgent semi-natural habitats can sometimes lead to the manifestation of unusually diverse assemblages of plants and animals,” explains Kite.

Jamie Robins, projects manager at

Canvey Wick, Essex

Canvey Wick in Essex, Mark Nowers explains, was initially a dumping ground for extractions from the River Thames and later prepared for use as an oil refinery in the 1970s, but never used. Over the past 20 years, it has become recognised as a “hotbed of biodiversity” owing to its history, climate and land use.

It supports nearly 2,000 invertebrate species, many of which are locally or nationally rare (Barkham, 2017), including some believed to be extinct in Britain. This invertebrate variety together with native trees, plants and flowers support a range of animal and bird species. Whitethroat, stonechat, reed warbler and green woodpecker can all be found there. The site was designated as a Site of Special Scientific Interest in 2005 after a three-year campaign partly spearheaded by local residents. It is the first brownfield site to be protected specifically for its invertebrates, and as a nature reserve is managed by Buglife and the RSPB.

Buglife agrees. “Brownfields are often some of our last remaining havens for nature in an increasingly managed landscape – whether urban or the countryside.”

Many of the habitat features that develop as a result of the longterm cycles of disturbance and abandonment of brownfield land “mimic natural habitats lost in the wider landscape”. He cites the Thames Estuary as an example of this, “as the network of brownfields there and the Open Mosaic Habitat on Previously Developed Land (OMHPDL) that they support provides a surrogate to the Thames Terrace Grasslands that have been lost to agriculture and industry”.

The balance

The government’s planning white paper, Planning for the Future, which will be the basis of a planning bill, proposes that local plans should identify three types of land – growth areas suitable for substantial development, renewal areas suitable for development, and areas that are protected.

It isn't clear where brownfield land will fall, most likely under the renewal

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Wigan Flashes

According to the Lancashire Wildlife Trust’s website, the ‘flashes’ are lakes formed through mining subsidence. They were partially filled with colliery waste and ash from the former Westwood Power Station, and through natural recolonisation and large-scale reclamation works, the industrial scars began to heal.

The mosaic of open water, reedbed, fen, rough grassland, wet woodland and scrub habitats support an array of plants and animals. They join important reserves like Abram Flash SSSI and Hope Carr Nature Reserve to form a 9km wetland retreat along the LeedsLiverpool Canal. and growth categories. What is the balance then between developing such land, some of which is proven to be rich in biodiversity, and protecting greenfield or green belt land?

For RSPB conservation officer Mark Nowers, decision-making must be rooted in evidence for the pros and cons and on a case-by-case basis, of both types of land. There must be a requirement in any planning system for onsite ecological assessment before development consent, or codified zoning, takes place. Before decisions are made on redevelopment or a sites’ future use, “everyone must first understand the full biodiversity value of the individual brownfield site”.

Robins agrees. To achieve a balance, sites need to be judged on their own merits and we must be careful about

The Wigan Flashes is formed of a series of shallow ponds created by subsidence caused by mining. Below: A fox dozes in an abandoned tennis court in south west London

the language used – “it is times like this that a ‘brownfield-first policy’ isn’t helpful”.

“As much as we would like sites to fit into neat pigeonholes, they often don’t. If we want to prioritise wildlife, then sites must be assessed on the basis of their wildlife value, not whether or not they fit the ill-defined and outdated criteria of brownfield and greenfield." He adds that there are many green belt areas which “are simply not delivering a great deal for wildlife, while in stark contrast there are brownfield sites that support some of our most threatened species”.

Likewise, Sue Young, head of planning at The Wildlife Trusts,

believes that where nature has returned to brownfield sites, “it is desperately important to carry out appropriate environmental assessments to ensure new development doesn’t disturb or damage potentially rare, endangered, or protected species”.

Decisions, she insists, should be made on a case-by-case basis.

Noting that the criteria for each area has not been set out, Kite believes it will come down to how the rules for each area type are written that determines how well the policy operates. “If they are badly written, then many biodiverse brownfield sites might be consigned to oblivion without their ecological value ever having been adequately recognised, or conversely, land that is ideal for development being assigned to categories that unnecessarily constrain development.”

For example, he says current indications suggest that green belt land will fall in the protected category, “but much of the green belt is biodiversitypoor, intensively managed farmland of little ecological value”.

To be a success, and with decisionmaking front-loaded, environmental assessment work must also be frontloaded. “We cannot allow a situation to arise whereby decisions about the acceptability ‘in principle’ of developing land are made in the absence of any knowledge about that land.”

Of course, if local planning authorities are expected to make key decisions earlier on in the process, and evidence them, resources will be required. Many, Kite highlights, do not even employ an ecologist.

In agreement, Nowers says the RSPB has previously called for all local authorities to have ecologists and arboriculturists on staff or available on contract. He welcomed the principle of a resources and skills strategy for the planning sector as proposed in the white paper, but says it must not be a document that merely highlights known needs and makes recommendations to address them. It must “guide the direction of a proper public funding settlement for the sector”.

Prioritising wildlife-rich land

Current policy support for brownfield land is “patchy”, according to Kite. Many species that could be found on brownfield sites are listed under Section 41 of the NERC Act 2006 as ‘priority’ species, which local planning authorities should ‘have regard’ to. The National Planning Policy Framework (NPPF) is less specific and considers biodiversity generally.

The environment bill sets out ambitious targets for expanding native woodland. Broughton says brownfield sites are good candidates for this as they will often develop through natural regeneration, without always needing to resort to planting trees. This, however, as noted before, will come down to recognising sites that are high in biodiversity.

“Recognising and protecting these habitats in local planning would be important for safeguarding their longterm progression to natural woodland, with potential benefits for nature recovery and carbon capture, and providing green spaces for wildlife and people,” says Broughton.

Greenfield and green belt land can also be enhanced to serve wildlife better. The government wants new housing developments to achieve at least a 10 per cent net gain in value for biodiversity.

Responding to the planning white paper consultation last year, the RTPI proposed that principal authorities prepare ‘Local Environment Improvement Plans’ to draw together currently disparate streams of environmental funding and planning to support the delivery of blue and green infrastructure strategies. Richard Blyth, head of policy, practice and research at the

RTPI, says the Local Nature Recovery Strategy proposed by the Department for Environment, Food and Rural Affairs could be a starting point for this but they would need to go further. Nowers believes these should be given formal weight in the land-use planning system so they are embedded within the local plan preparation process. Of course, brownfield sites are going to be developed: they might be the best, well-connected spot for new development. If that is the case, Broughton says a portion should be left to develop naturally so it can retain its biodiversity and, Kite adds, they can often be developed without losing ecological interest.

Every space counts

The brownfield versus greenfield question is one that cannot be ignored if species' decline is to be prevented and their fortunes changed, but there is a balance to be struck. As Nowers says, striking such a balance is “core to what good planning is about”. And, as Young maintains, “nature must be at the heart of decision-making for all current and future development, from planning and design through to longterm management and maintenance”. The Planner’s contributors agree that each site type – brown and green – must be assessed on its own merits. The way policies, and the planning and environment bills, are worded is important and there must be a complete data set and ecological assessment to get them right. For those sites that are developed, as Kite says, they must be made to work hard. There are several innovative ways "WE CANNOT ALLOW to retrofit biodiversity enhancements A SITUATION TO into new development, he explains – ARISE WHEREBY integrated bat or bird boxes, bee bricks, DECISIONS ABOUT edible hedgerows, wildflower verges, THE ACCEPTABILITY ponds/SUDs, hedgehog highways, green ‘IN PRINCIPLE’ OF roofs and green walls – “the list is vast”. DEVELOPING LAND IS “All of these tools need to be brought MADE IN THE ABSENCE to bear through policy, and land needs OF ANY KNOWLEDGE to be made to work hard – every space ABOUT THAT LAND” – can make some contribution toward BEN KITE biodiversity restoration.”