‘Brownfields can be rich habitats': the abandoned oil refinery where wildlife now thrives

The Guardian

a day ago

'You must see this!' Marc Outten shoulders past tangles of blackthorn and shimmies around hummocks of blackberries the size of buses and glades filled with wildflowers. What beautiful wildlife spectacle awaits?
Weaving across carpets of bird's foot trefoil, we reach our destination: a vast, barren circle of asphalt, 70 metres across – the ruins of an uncompleted oil refinery.
'You'll find rare bees and reptiles around the edge and you've got these lovely stonecrops and lichens,' enthuses Outten, a naturalist and RSPB's site manager for Canvey Wick nature reserve. The derelict asphalt pad is buzzing with rare nature.
This 'ruined' landscape – where disused street lamps poke up above rampant scrub – resembles some kind of post-apocalyptic London. But in its ruination, this brownfield site beside the Thames in Essex has become one of the most nature-rich places in Britain, home to 3,200 species including endangered shrill carder bees, pantaloon bees, water vole, cuckoos and long-eared owls.
Canvey Wick is celebrating its 20th anniversary as a site of special scientific interest (SSSI) as conservationists warn many similarly wildlife-rich brownfield sites are threatened by development, particularly in the Thames Gateway.
Tilbury ash fields, home to 185 invertebrate species of conservation concern including the great sneak-spider, is imperilled by plans to expand the port of Tilbury. Meanwhile, a Google datacentre is proposed on a local wildlife site close to Lakeside that is home to nightingales, rare plants and scarce invertebrates such as the brown-banded carder bee.
Canvey Wick shows what can happen when a brownfield site is protected. Since it was bought by the Land Trust and managed by the RSPB in partnership with Buglife, an astonishing range of rare species have made their home on its 93 hectares (230 acres): 11.7% of its 3,200 species are classified as rare, scarce, threatened or near threatened.
Eight years ago, there were no nightingales on Canvey Wick. Today there are 21 nightingale territories in the thickets of blackthorn, hawthorn and bramble – a vital new stronghold for the much-loved but endangered songbird.
'People assume that brownfield sites are very low value for biodiversity – until they see what a brownfield site can really do,' said Outten, on a tour of the site during which we find pantaloon bees, spectacular Jersey tiger moths and increasingly rare wall brown butterflies. 'If brownfield sites are left to sit around for a while, they develop into really rich habitats. This would've been a very desolate space full of sand, concrete and tarmac and now we've got this wonderful nature reserve. There's so much structural diversity and the more structural diversity you have, the more biodiversity you have – that's what makes this place so special.'
Canvey Wick was green grazing marshes until humans ruined them – and inadvertently made one of the most nature-rich places in Britain.
An oil refinery was planned for Canvey Wick in the early 1970s. The ground was raised with dredging from the Thames: sands, shingle and even seashells. Concrete roads and street lamps were built. Thirty two and a half circular asphalt pads were constructed as bases for vast oil storage containers. And then the 1973 oil price shock halted work. The refinery was abandoned.
Over the next 50 years, nature raced in. The unusual diversity of soil types and hot microclimates attracted an unusual range of invertebrates: there are 250 species of bee, wasp and ant on the site, including the brown-banded carder bee, five-banded weevil-wasp and carrot mining bee. They feed on an unconventional mix of native and non-native flowers including bristly oxtongue and everlasting pea.
As the human ruins subside beneath greenery, conservationists must manage the rapidly changing site to balance the competing needs of different rare species. What's great for nightingales – more scrub – will cause many heat-loving invertebrates to disappear. When the site was first designated an SSSI in 2005, there was just 15% scrub and tree cover. Today it is more like 70%.
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'Some scrub is great but having that open mosaic flower-rich grassland is really important,' says Outten. 'How do you strike the balance between clearing areas and retaining nightingale habitat? A lot of this is cutting-edge stuff. 'Restoring' brownfield is not something many organisations have got into.'
A three-year project at Canvey has cut back some scrub, and created new scrapes of bare sand required by rare invertebrates and species such as adders. The cut-and-scraped areas are now burgeoning with wildflowers and insects again, while cleared ditches are home to scarce emerald damselflies and blue-eyed hawker dragonflies.
Conservationists hope it will inspire the creation of more brownfield nature reserves. 'Canvey Wick demonstrates how brownfield sites can be transformed into vibrant green spaces that serve the community and provide important habitats for wildlife,' says Alan Carter, the chief executive of the Land Trust. 'We are extremely proud of the regeneration efforts carried out since taking on the ownership of the site in 2012. The site is now one of the top locations in Britain for endangered invertebrates, an impressive achievement.'
Although important parts of Swanscombe peninsula were saved from development threats when Natural England designated it an SSSI in 2021, Buglife is calling on the government's wildlife watchdog to urgently give more sites the same protection, including Tilbury ash fields. Natural England has 'Thames estuary invertebrates' in Essex and Kent listed in its SSSI designation 'pipeline' but the watchdog has been criticised for failing to designate many endangered places in recent years.
Carl Bunnage, head of nature policy at RSPB, said: 'Brownfield sites are not always just dead, ugly and abandoned spaces. Indeed, as Canvey Wick shows, they can provide specialist habitats and be havens for nature – full of life of all kinds. With the government currently driving reforms to the planning system in England, and prioritising the re-development of brownfield sites, it is vital that the nature-value of sites is properly assessed before planning decisions are taken.'
Conservationists hope Canvey Wick can also inspire smaller ways of attracting rare wildlife: depositing piles of sand or crushed concrete on a place may not look conventionally pretty but it will create soils and microclimates where myriad wildflowers and invertebrates can thrive.
Outten, who was raised in the area, hopes Canvey will inspire the creation of other similar nature reserves so there is a network for rare species, which can be enjoyed by the local community as well.
'People feel passionately about it. We want to strike the balance between giving people a place where they can access green space but also protect the species that the site is important for. It's a unique place. There's nowhere else like it,' he said.