Rare butterflies booming after conservation boost

High Brown Fritillary in the sun on a plant
Published : 17 Aug 2017

Some of Britain’s rarest butterflies are booming at our sites, a new report has found.

The study, led by charity Butterfly Conservation, revealed that rare species like marsh fritillary are bucking nationwide declines, with these ‘habitat specialist’ butterflies seeing their numbers grow by a tenth at National Trust sites since 1992.

It follows decades of work by our advisers and rangers to protect the specialist habitats demanded by struggling butterfly species like the Duke of Burgundy and pearl-bordered fritillary.

We’re also working to restore numbers of farmland butterflies on our land to 1976-levels.

Increased in abundance

Researchers from Butterfly Conservation used results from the UK Butterfly Monitoring Scheme to compare butterfly numbers at our sites to those under other ownerships.

They found that ‘habitat specialist’ butterflies like the chalk grassland-loving Adonis blue have increased by 13 per cent at our places since 1992.

Overall, scarcer butterflies have declined by a quarter (25 per cent) in the British countryside in the last 25 years.

Matthew Oates, National Trust butterfly specialist, said: ‘Many of Britain’s scarcest butterflies are doing relatively well at our places, with rangers and tenant farmers working together to protect important habitats.

‘Nationally, butterflies like the beautiful Duke of Burgundy are experiencing steady declines as a consequence of habitat loss and, most probably, climate change.’

Working with local farmers

Among the winners identified in the report led by Butterfly Conservation is the marsh fritillary, which has seen its numbers grow by five per cent year on year on National Trust sites over the last 25 years. In Ennerdale our rangers are working with local farmers who are grazing the wet flush grassland habitat with cattle to provide the perfect conditions for the marsh fritillary caterpillars.

" Many of Britain’s scarcest butterflies are doing relatively well at our places, with rangers and tenant farmers working together to protect important habitats."
- Matthew Oates, specialist volunteer on butterflies

Professor Tom Brereton, head of monitoring at Butterfly Conservation, said: ‘The results are highly encouraging and demonstrate that with targeted and tailored habitat management we can turn around the fortunes of many threatened butterfly species.’

Despite concerted effort, a small number of scarce species are still declining on National Trust land. They include the endangered High Brown Fritillary and Heath Fritillary butterflies.

More common butterfly species, such as the Meadow Brown and Cabbage White, were found to be less abundant on National Trust sites than in the wider countryside.

Our pledge

We’re now hoping to boost the number of farmland butterflies on our 200,000 acres of farmed land. We’ve pledged to improve butterfly habitats on land in our care, with the hope of boosting the ranges of rarer ‘habitat specialists’ like Adonis blue by 50 per cent.

We’ll work closely with Butterfly Conservation to better manage butterfly sites and to monitor our progress.