Bracken management project supports rare butterfly in North Wales

A long-term conservation project to support one of Wales’ rarest butterflies is continuing at Pwll Glas, Denbighshire.

Natural Resources Wales (NRW) and Butterfly Conservation are working together to manage bracken for the benefit of the pearl-bordered fritillary. The project at Eyarth Rocks Reserve focuses on careful bracken management to help maintain the ideal habitat conditions for this delicate species.

This targeted conservation effort is vital, as the pearl-bordered fritillary is only found at a handful of locations in Wales. Protecting its habitat is also a key part of maintaining the Site of Special Scientific Interest (SSSI) status of these areas.

The pearl-bordered fritillary butterfly relies on bracken for survival. During summer, the adult butterflies lay their eggs amongst the bracken, and once the caterpillars hatch, they depend on the warm bracken litter on the ground to develop. The caterpillars feed on violets, which require the right balance of bracken cover to thrive. Without active management, scrub encroachment could threaten these essential conditions.

The work, carried out by Butterfly Conservation with funding from NRW, involved cutting bracken and removing scrub between October and December 2024 to maintain an open, warm habitat. This helps ensure that both the violets and the butterflies can flourish.

Rhys Ellis, Denbighshire Environment Team Leader at NRW, said:

“This work is a fantastic example of long-term partnership work making a real difference. The pearl-bordered fritillary is a rare and vulnerable species, and managing its habitat is essential to its survival. By carefully controlling bracken and scrub, we’re helping ensure that this butterfly continues to have the right conditions to thrive in Denbighshire.”

Alan Sumnall, Butterfly Conservation’s Head of Conservation for Wales and Northern Ireland, said:

“The pearl-bordered fritillary was once widespread across Wales but is now one of the most rapidly declining butterfly species, highly threatened throughout its range in Britain, with declines of 88%. Projects like this, based on our Eyarth Rocks nature reserve at Pwll Glas, are incredibly important for rare butterflies, based on sound evidence of the species ecological requirements, especially against a backdrop of more than half of UK butterflies showing long term decline for the first time.

“Alongside the bracken management which is vital for the survival of many of our fritillary species, we are monitoring the results to ensure the best management due to the impacts of climate change. We are delighted to be working with Natural Resources Wales to ensure ideal habitat for the pearl-bordered fritillary and other butterflies associated with bracken in Wales.”