Please donate to help prevent the local extinction of one of the UK’s most threatened and iconic species – the Marsh Fritillary butterfly (Euphydryas aurinia).

The butterfly has undergone catastrophic declines throughout much Europe and the UK in recent decades. Although Wales remains a relative stronghold, even here many localised extinctions have taken place.

“If we are to truly reverse the decline of nature in Wales it is clear that we need additional approaches to nature conservation. It’s great to see such positive action for the iconic Marsh Fritillary butterfly and to think that although this might be the first project of its kind in Wales, it won’t be the last”

Iolo Williams: TV Broadcaster and Naturalist

After years of preparation and planning, INCC received a licence in late 2020 to collect 80 caterpillars from the wild to start a captive breeding and rearing programme. In spring 2021, INCC, along with project partners collected 80 Marsh Fritillary caterpillars with the aim of restoring a dwindling population in the Upper Ely landscape of South Wales.

Once collected, the caterpillars were moved to rearing pens situated at the National Botanic Garden of Wales and allowed to pupate. The emerging adult butterflies bred and laid eggs in the Devil’s-bit Scabious provided for them – the main foodplant of the caterpillars. In September 2021, the first of batch of caterpillars were put out onto Llantrisant Common, the first of thousands planned to be released into the landscape over the next few years to help boost the population.

The first Marsh Fritillaries released onto Llantrisant Common in 2021
Marsh Fritillaries seen through thermal scope in spring 2022

In 2022 we were delighted to find that the caterpillars had successfully survived hibernation and proceeded to pupate and hatch. On the 11th of May 2022 we saw the first Marsh Fritillary flying on the Common since the mid-1990s!

During the flying season in May and June, hundreds of Marsh Fritillary butterflies were seen across the common. Local school children and volunteers who have helped the project at every stage were able to see all their hard work up close. The local school, Ysgol Gymraeg Castellau have been crucial to the project and have encouraged pupils to take an active part in the survey and monitoring of the Marsh Fritillary locally. Hopefully, many of the children will grow up to be the Marsh Fritillary champions of the future.

Later in the year a survey of the Common found 193 larval webs – a great result for the first year. In the year since we have released more caterpillars on to the Common while starting to bring other marshy grassland habitat in the landscape into good condition.

The project is scheduled to continue for another 5 years: one more year of releases, then 4 years of monitoring the Common and the surrounding landscape in the hope that the butterflies flourish and disperse to other patches of suitable habitat.

The project would not have been the success it has been so far without help from volunteers, project partners, funders and many others – thank you for your continued support.

Support the project

Why the Marsh Fritillary Butterfly

Conservation for Marsh Fritillaries in Wales has for many years focused on monitoring populations and trying to influence policy to better manage existing habitats. Despite the tireless work of volunteers, conservation organisations and many landowners, the Marsh Fritillary continues to decline. It is becoming increasingly apparent that greater conservation effort is needed if we are to protect the species from further localised extinctions in Wales.

Marsh Fritillary Caterpillars in Larval Web

Due to national and international declines, Marsh Fritillaries are included on Annex II of EEC/EU Habitat and Species Directive. A total of ten Special Areas of Conservation (SACs) have been designated in Wales, where the Marsh Fritillary is a primary reason for site selection. The species is also listed as ‘a living organism of principal importance for the purpose of maintaining and enhancing biodiversity in relation to Wales’ (Environment (Wales) Act 2016).

The decline of the species is associated with the loss of its marshy grassland and rhôs pasture habitat. When managed appropriately these habitats provide the ideal sward structure required by the caterpillars and their food plant. The loss of grassland habitats, predominantly through agricultural intensification, has resulted in fragmented landscapes which support fewer and fewer areas suitable for the species.

Cattle grazing is the best way to manage Marsh Fritillary habitat.

Project Location
The population restoration project is taking place in South Wales, within the Upper Ely landscape encompassing the towns of Llantrisant and Tonyrefail. Despite its UK significance the Upper Ely Marsh Fritillary population is declining and has been in steady, continuous decline for at least 25 years.

A key area for the butterfly is Llantrisant Common, situated to the south of the landscape and covering an area of over 113 ha of contiguous rhôs pasture habitat. A combination of historic and current extensive cattle grazing has created the ideal habitat for Marsh Fritillaries with an abundance of Devil’s-bit Scabious and other wetland vegetation. Despite this, the butterfly has not been seen on the Common in over 20 years.