Canvey Wick in Essex, once an abandoned oil refinery, has transformed into a thriving wildlife sanctuary, showcasing the ecological potential of brownfield sites. The 93-hectare site now hosts 3,200 species, including endangered shrill carder bees, pantaloon bees, water voles, cuckoos, and long-eared owls. It was designated a Site of Special Scientific Interest (SSSI) 20 years ago and is managed by the RSPB and Buglife in partnership with the Land Trust.
The site was originally green grazing marshes before construction of an oil refinery began in the early 1970s. The ground was raised with dredged Thames sand, shingle, and seashells, and 32 circular asphalt pads were built for oil storage. However, the 1973 oil price shock halted work, and the refinery was abandoned. Over the next 50 years, nature reclaimed the area, creating a diverse habitat with unusual soil types and hot microclimates that attract rare invertebrates.
Naturalist Marc Outten, RSPB site manager, noted the site's structural diversity, which supports a wide range of species. He highlighted the presence of rare bees, reptiles, stonecrops, and lichens on the barren asphalt pads. The site now includes 21 nightingale territories, up from none eight years ago, and 250 species of bees, wasps, and ants.
Conservationists warn that similar wildlife-rich brownfield sites, such as Tilbury ash fields and a site near Lakeside, are threatened by development. Tilbury ash fields, home to 185 invertebrate species of conservation concern, face expansion of the port of Tilbury, while a proposed Google datacentre threatens a local wildlife site with nightingales and rare plants.
Managing Canvey Wick requires balancing competing needs, as increasing scrub benefits nightingales but threatens heat-loving invertebrates. Scrub cover has risen from 15% to 70% since 2005, and Outten emphasised the importance of maintaining open mosaic flower-rich grassland. The site demonstrates that brownfield sites can become rich habitats if left undisturbed.
