Abandoned oil refinery now a thriving hotspot for over 3,200 species

To many people Canvey Wick in Essex is an unlikely nature reserve. Tucked away on a low-lying piece of reclaimed land next to the Thames Estuary, the site was once ear-marked for an oil refinery. Yet today it’s one of the UK’s most significant places for invertebrates, with more than 3,200 insects, birds, plants and other species found here.

Back in the 1970s, work began to turn the area’s original grazing marshes into an oil refinery, and the land was raised by covering it with a thick layer of silt, sand, gravel and shell fragments dredged from the Thames. But the oil crises that rocked the seventies put an end to the refinery, and the area was pretty much abandoned for 30 years.

Today, thanks to the combined efforts of the RSPB nature reserve team, volunteers, local wildlife recorders, partners at Buglife, and landowners, the Land Trust, the area is a thriving “brownfield oasis”.  In 2005, it was the first brownfield site to be protected specifically for invertebrates and designated a Site of Special Scientific Interest (SSSI).

The site’s open mosaic of flower-rich grassland makes it a hotspot for invertebrates, including many which are rare or threatened.  More than 250 species of bees, wasps and ants have been recorded, including the Shrill Carder Bee, Brown-banded Carder Bee, Five-banded Weevil-wasp and Carrot Mining Bee. The myriad of flowers, such as everlasting pea, trefoils and vetches, all provide invaluable food.

Shrill Carder Bees, named for the high-pitched buzz made when flying, have experienced steep declines in the UK due to loss of suitable flower-rich habitat. Now restricted to a handful of locations, they are a priority species for the RSPB.

Shrill Carder Bees have a pale straw colour, distinctive black band on the thorax and orange tail giving this dainty bumblebee a unique appearance. Canvey Wick has offered the bee a lifeline. 

Adders, Common Lizards and Slow-worms are also found here, thanks to the creation of bare sand areas through scraping, which is vital for basking reptiles.

Ongoing habitat management is also supporting a range of other wildlife, including a growing number of Nightingales. Red-listed as of the highest conservation concern in the UK, Nightingales have declined sharply in the UK, with breeding populations having dropped 41% between 1995 and 2023. In Canvey Wick, however, numbers are on the up.

In 2021, 11 territorial males were recorded during the RSPB’s breeding bird surveys. The following year, major habitat restoration works were undertaken at Canvey Wick for the benefit of the site’s rare invertebrate communities, and it became clear that Nightingales needed to be factored into the planning of this. Working with territory mapping and vegetation structure data, the site team actively avoided clearing certain scrub areas for the benefit of Nightingales. As a result, 2023 saw an increase to 13 singing males with 21 recorded in 2024 – a 61% increase on the previous year. In 2025 that number stayed consistent at 21 territories. 

Reflecting on the nature reserve’s success as a hotspot for wildlife, Canvey Wick Nature Reserve Manager, Marc Outten, said:

“Canvey Wick is a hugely important place for wildlife. We are proud of the role our reserve team, volunteers and partners have played in maintaining such a rich habitat. The wildlife found here includes some of the most threatened in the UK, such as the Shrill Carder Bee, and to see them benefit from our efforts is something to be celebrated – more than 3,200 species is a fantastic success.

“Striking a balance between clearing and avoiding scrub for the benefit of the local Nightingale population whilst maintaining the open flower-rich grasslands and bare ground for rare invertebrates, was a challenge made easier by data collected by local specialists, the reserve team and volunteers. This important data informed discussions with Natural England and our partners, the Land Trust and Buglife. The clear impact of work completed at the reserve, alongside the decision to leave some scrub areas untouched, can be seen in the increase of Nightingale numbers at Canvey Wick.”