Wicken Fen Becomes First UK Nature Reserve to Record 10,000 Species

Wicken Fen nature reserve in Cambridgeshire has officially recorded its 10,000th species of wildlife, becoming, experts believe, the first nature reserve in the UK to reach this milestone.

The landmark total was achieved earlier this year with the discovery of a rare moth, the six-belted clearwing, which was recorded on the reserve for the first time.

The species, known for its striped yellow abdomen that mimics a wasp’s appearance to deter predators, marks the latest addition to a long history of wildlife discoveries at Wicken Fen.

Wildlife recording at the fen dates back more than 200 years. During the 20th century alone, 13 species new to science were identified at the site.

According to experts at the National Trust, the number of recorded species has surged in the past 25 years due to a major expansion of the reserve begun in 1999, rising temperatures that have enabled more insects to move northwards, and the use of advanced monitoring technologies.

Alan Kell, Countryside Manager at the National Trust, said:

“Reaching 10,000 recorded species is a proud achievement for everyone who has ever taken an interest in this special corner of the country.

When the National Trust bought Wicken for £10 back in 1899, it was only two acres in size. A concerted effort over time to expand, restore and care for it has created this haven for wildlife that is a thousand times the size it was and now the nature reserve with the most recorded species in the UK.

I never fail to be surprised by what we find here, and it is absolutely a case in point that if you give nature the opportunity and the space, it will do remarkable things.”

Expansion and Restoration

Wicken Fen’s transformation began with the National Trust’s “Wicken Fen Vision,” a century-long plan launched in 1999 to expand the reserve and safeguard fenland habitats. At that time, a biodiversity checklist recorded 7,421 species. Since then, the site has grown from 225 hectares to 820 hectares, significantly increasing its abundance and diversity of wildlife.

Recent notable finds include the formidable ant beetle, the rare grass vetchling plant, and the chamomile shark moth. Bird records have also expanded, with sightings of a white-tailed eagle in 2022 and a white stork in summer 2023.

Some species, however, have disappeared from the fen. The swallowtail butterfly, once found there, is now extinct at Wicken due to habitat loss—a loss that inspired the original Wicken Fen Vision.

New Partnership for Peatland Recovery

The National Trust has announced a new partnership with The Nature Recovery Project to restore lowland peat habitats at Wicken Fen and other sites across the UK. The initiative will create new wetland areas, preserve peat soils, and support innovative wetland farming methods known as paludiculture.

James Berry, Head of Strategy at The Nature Recovery Project, said:

“The Nature Recovery Project is excited about the opportunity to unite the critical environmental benefits of lowland peatland restoration with a sustainable commercial purpose.

If the project can demonstrate that healthy, thriving peatlands can successfully coexist with profitable food production and nature, we anticipate that this approach could be adopted widely across both existing and historically degraded peatlands. This would unlock a powerful pathway for stopping emissions from the nation’s largest natural emitter.”

Technology and the Future of Monitoring

Wicken Fen is also contributing to cutting-edge biodiversity research through The Bioscan Project, led by the Wellcome Sanger Institute. The project uses DNA barcoding to identify insect species and monitor changes in biodiversity over time.

Lyndall Pereira da Conceicoa, Bioscan Science Lead at the Wellcome Sanger Institute, said:

“The Bioscan Project aims to revolutionise our understanding of insect diversity in the UK by using DNA barcoding to identify both known species and species that would otherwise remain unknown to science.

Our ambition is to use this approach to track how diversity changes through space and time across the country. Sites like Wicken Fen, with their rich biodiversity and long-term monitoring, are invaluable partners in creating comprehensive baselines of UK insect species that will inform conservation efforts for years to come.”

Alan Kell added:

“It is vital that we continue to restore as much fenland habitat as possible. To do so we’ll need to work in partnership, including with funders like The Nature Recovery Project, and increasingly beyond the physical boundaries of the reserve with fellow landowners. The more space we can provide and the more wildlife ‘corridors’ we can create, the greater chance we have of being able to support even more species – especially in this changing climate.”

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Wicken Fen’s Top 10 “Weird and Wonderful” Species

As chosen by Wicken Fen’s Ajay Tegala on the National Trust website

• Glow-worm – Larvae sometimes ride on snails’ backs and deliver a toxic bite to paralyse their prey.
• Common lizard – Can shed its still-moving tail to escape predators; the tail regrows shorter than the original.
• Fen nettle – Resembles a common nettle but lacks stinging hairs, instead having fine, dense, non-stinging ones.
• Norfolk hawker – Once found only near the Norfolk Broads, this dragonfly now breeds naturally at Wicken Fen.
• Water vole – Britain’s largest vole creates complex burrows with underwater entrances and unique defensive behaviours.
• Cuckoo – Known for brood parasitism; Wicken Fen was the site of pioneering cuckoo research by Professor Nick Davies.
• Silver barred moth – A very rare species found at only three other UK sites, with larvae feeding on two grass species.
• Water scorpion – Despite its name, not a true scorpion; its tail acts as a snorkel while it preys underwater.
• Greater bladderwort – A free-floating, carnivorous aquatic plant that traps and digests small prey using vacuum-like bladders.
• Clearwing moths – Mimic wasps and hornets in appearance and behaviour to avoid predators; the six-belted clearwing was Wicken Fen’s 10,000th recorded species.

Wicken Fen, managed by the National Trust, now stands as the UK’s most biodiverse nature reserve — a living record of over two centuries of natural history and a testament to the potential of large-scale habitat restoration.

Credit: National Trust