High brown fritillary butterfly. Photo, Chris Root
Devon Fritillary Recovery Project
4 fritillaries, 12 nature reserves, more than 100 hectares
Across England, many fritillary butterfly species have declined dramatically over the last 40 years.
The story is different in Devon. Targeted conservation work has seen astonishing success stories on DWT's nature reserves for some of our rarest species. For example, at a time of continuing national declines, the small pearl-bordered fritillaries saw an increase of 1,636% between 1988 and 2010 at Marsland nature reserve.
For the first time, between 2023 and 2025, DWT had the opportunity to build on 30 years’ worth of experience across 12 of its nature reserves to support four fritillary butterfly species: high brown, pearl-bordered, small pearl-bordered, and marsh fritillary.
This project is now complete. Here are just a few highlights of what was achieved:
Small Pearl-bordered Fritillary Butterfly. Photo credit- Chris Root
Pearl-bordered and small pearl-bordered fritillary
These woodland butterflies plummeted in numbers in the 20th century. Why? Because their life cycle requires just the right mix of light and shade at different times of year for egg-laying and for their caterpillars to feed on violets.
Originally evolving in woods where large mammals created that light and shade mix, the same conditions were maintained for centuries by human coppicing of woods for timber and cutting of bracken for a variety of uses. When this activity stopped, the butterflies lost their habitat and now need targeted land management to thrive.
Amy Lewis
Marsh fritillary
Found in wet grasslands, this species makes a home on several DWT nature reserves, both in northern Devon’s Culm grasslands and on Dartmoor, at Emsworthy Mire.
For its larval food plant, Devil’s-bit scabious, to grow in abundance, rotational cutting of scrub and rush is required in wetter and more remote parts of these reserves.
High brown fritillary © Stefan Johansson
High brown fritillary
Another butterfly whose caterpillars feed on violets, the same bracken management can also drive recovery of this species. It suffered huge nationwide declines between 1978 and 2022, the population dropping by two-thirds.
Machines and muscle
Previously, much of the habitat management on DWT's nature reserves had been carried out manually by hard working trainees and volunteers. With limited capacity and short time windows to carry out work, we couldn't create perfect conditions on every nature reserve for fritillary populations to thrive and spill over into neighbouring areas.
This was where specialist machinery helped create new opportunities to manage bracken, rush and scrub on steep slopes, wet mires and other terrain that is difficult to access on foot with hand-held tools. This project is the first time we had the right machinery and additional staff time to improve habitats for these butterflies in more areas, more efficiently.
Tree pipit © Derek Moore
The birds and the beetles
Restoring and re-creating habitats for these four fritillary species creates knock on benefits for other wildlife. We see an increase of other wildlife including tree pipits, nightjars and Kugelann’s green clock beetles on Dartmoor, and grasshopper warblers, lesser butterfly orchids and keeled skimmer dragonflies on wet grassland sites.
Marsland
Why Devon?
Despite national declines, Devon remained a vital stronghold for these four fritillaries, so it was critical to secure their long-term futures here. DWT played a pivotal role by helping populations recover on our own nature reserves, many of which lie at the heart of important fritillary habitats.
DWT had 30 years of experience restoring habitat for all four species. We pioneered successful bracken management techniques that have since been widely adopted nationally. By understanding the life cycle of the butterflies, we created just the right mix of light and shade at different times of year for egg-laying and for their caterpillars to feed on violets.
Project legacy plans
The vehicles and equipment purchased, including an aerial drone, will be maintained to increase efficiency in delivering more habitat management in a targeted way to help fritillaries and other species.
Each site has a five- or ten-year management plan that includes overall aims and objectives, with annual work programmes implemented by staff and volunteers, plus contractors where needed. These plans will be updated as more detailed site habitat mapping is produced.
The methodology for monitoring fritillary populations and habitat condition developed by the project officer will continue, based on:
- All fritillaries annual adult time counts
- Marsh fritillary larval web counts
- Aerial drone mapping of habitat management work
- Condition assessment of habitat suitability for relevant fritillary species
This will all help to meet the five-year obligation period required by Natural England as project funder.
Explore DWT's nature reserves - home to these rare butterflies
Generously funded by
This project was made possible thanks to the support of Natural England’s Species Recovery Programme Capital Grant Scheme.
Additional thanks to our generous supporters who donated £24,503 to the Devon's Fabulous Fritillaries appeal, enabling DWT to achieve its goals.
