The High Brown Fritillary Argynnis adippe is Britain’s most threatened butterfly. This species has lost 85 per cent of its population since the 1970s.
The Morecambe Bay Limestones and to a lesser extent, the South Cumbria Low Fells to the north, are the UK’s national stronghold supporting two-thirds of the remaining populations.
The Morecambe Bay Limestones sites provide limestone or acid grassland, pavement, Bracken, scrub and woodland habitats. Common Dog-violet Viola riviniana is the main larval foodplant.
Efforts to conserve the butterfly began as long ago as the mid-1980s and have continued to the present day under the auspices of the High Brown Fritillary Action Group which comprises 11 partner organisations. Despite the measures being taken, monitoring showed that the High Brown Fritillary had declined overall in this landscape by 40% between 1990 and 2007. However populations on actively managed sites were stable in comparison to a 74% decline on largely unmanaged sites.
In 2008 a four year programme of coordinated and targeted management commenced to reverse the regional decline of the High Brown Fritillary.
- The creation of potential breeding habitat through clearings, using specialist contractors.
- Improvement of site connectivity through ride management by contractors, to aid dispersal and increase opportunities for natural colonisation of former sites.
- Project officers liaised with partner organisations, landowners and contractors to ensure management was undertaken at locations most likely to produce suitable breeding habitat.
- Habitat condition assessments and species surveys of all the new clearings and rides.
- Recruitment and training volunteers to assist with practical management and monitoring.
For more detailed information about this project and others across the UK please read the full report: Landscape-scale Conservation For Butterflies And Moths: Lessons From The UK.
- After the first three years, at least 89 clearings and 25 rides had been managed, potentially restoring 60 ha habitat on 23 sites.
- By 2011, the High Brown Fritillary had already colonised 23% of the clearings and rides and probably many more because in another 37% of clearings/rides large fritillaries were recorded but were not positively identified as either High Brown or Dark Green Fritillary Argynnis aglaja.
- Between 2009 and 2011 the butterfly recolonised two former sites, including one where it had not been recorded since 1983, and colonised two with no previous records, a 29% increase in occupancy of the project sites.
- The project has been beneficial for a number of other UK BAP Priority Species butterflies and moths utilizing similar habitat. The spring-flying Pearl-bordered Fritillary was known to have re/colonised two sites, the Duke of Burgundy, one new site and the pyralid moth Anania funebris re/colonised two sites. The early summer species, Northern Brown Argus and Small Pearl-bordered Fritillary have also been recorded from about a quarter of the clearings.
Since the project’s inception Forestry Commission England (FCE) agreed to target the landscape with Woodland Improvement Grants (WIGs), part of the English Woodland Grant Scheme (eWGS), to the tune of £250k. Landowners were able to claim grants for coppicing, thinning and ride management. This not only increases the scope of the project but helps sustain the project outcomes for a much longer period.