Delaying grass cutting until late summer has dramatically increased butterfly populations at an ancient Essex forest. The National Trust reports that Hatfield Forest now hosts 24 butterfly species, reaching a 17-year high in recorded diversity.
The reserve has seen particularly strong numbers of marbled-white and small heath butterflies this year. Sightings of the elusive purple emperor have also increased significantly across the ancient woodland.
Management strategy change
Two years ago, the National Trust altered its grassland management approach at the medieval hunting forest. Previously, grass and wildflowers were mechanically cut in June, but this timing has been pushed back to late July and August.
James Rowland, National Trust operations manager at Hatfield Forest, said: "Each year the grass, including the wildflowers, would be mechanically cut in June, but by delaying this as long as possible, to late July into August, we're allowing flowering species to remain in flower for longer, providing greater benefit to nectar-reliant species."
The delayed cutting allows even plants like thistle and ragwort to bloom longer before turning to seed. These species provide crucial nectar sources for butterflies and other pollinators, despite potentially outcompeting other flora without proper management.
Cattle create optimal conditions
Red poll cattle play an essential role in maintaining the ideal environment for wildflowers to flourish. The animals help control scrub growth while breaking up compacted soil through their grazing patterns.
The trust now retains a small herd throughout winter months to suppress bramble and other scrub species. This winter grazing also prevents thick plant matter from smothering the following spring's grass and wildflower growth.
Climate and weather factors
While the management changes have had the biggest impact, a hot and dry spring also contributed to this year's high butterfly numbers. Rowland emphasised the growing importance of sustaining nectar sources as summers become hotter and drought conditions more frequent.
During dry spells, hardy species like thistle and ragwort become lifelines for many invertebrates when other grassland plants decline. These resilient plants provide crucial nectar during peak drought periods.
Survey history and heritage
Official butterfly records at the forest began in 2008, though staff and volunteers have conducted annual surveys for over 50 years. The National Trust describes Hatfield Forest as the "most complete example of a medieval royal hunting forest surviving today."
Ancient royal heritage
The forest has a remarkable history dating back over 950 years. King Harold owned the land immediately before the Norman Conquest in 1066, after which it passed to William following his victory at the Battle of Hastings.
Henry I established the royal hunting forest around 1100, with royal hunting rights continuing until 1446. The forest is documented in the Domesday Book of 1086, cementing its place in English medieval history.
Sources used: "PA Media" Note: This article has been edited with the help of Artificial Intelligence.
