Butterflies in the UK are struggling to survive with a changing climate and ecosystem, a survey carried out over the last 50 years has shown – but Purbeck in Dorset is bucking the trend.
Figures collated by East Lulworth’s Butterfly Conservation charity – which has Sir David Attenborough as its president – has shown that more than half of UK’s native butterfly species are fading fast, but in Purbeck the picture is more promising.
A large tortoiseshell, thought to be extinct in the UK, was pictured on Ballard Down in spring 2026 by Shona Refoy
Large tortoiseshell spotted on Ballard Down
Purbeck’s outstanding record of conservation work, is showing that even threatened butterflies are increasing in numbers, while the species that are taking full advantage of warmer summers are having a field day.
So far in 2026, the large tortoiseshell, a butterfly classed as extinct in the UK for more than 30 years, has been spotted on Ballard Down near Swanage, while small coppers, wall browns and green veined whites – all in a state of rapid decline elsewhere in the country – have shown up between Swanage and Lulworth Cove.
And graylings, silver studded blues and Lulworth skippers, which all came close to dying out in England, are showing signs of increasing their numbers again after getting a toehold in the Purbeck countryside.
The purple emperor has been one of the biggest winners over the past 50 years
33 of 59 UK species are in decline
But fifty years of data from the UK Butterfly Monitoring Scheme (UKBMS) released on Wednesday 15th April 2026, shows that 33 of the UK’s 59 native butterfly species have declined in numbers over that time as their traditional grounds, like grasslands and woodland, have been squeezed out.
Some species like red admirals, purple emperors, and commas have surged in numbers, because their caterpillars feed on common plants like nettles, and have spread ever further northwards as summers get warmer and longer.
But those that rely on specific habitats, like woodland glades, chalk downland or heathland have struggled to cope – except in spots like Purbeck where the countryside is protected.
Richard Fox, head of science at Butterfly Conservation, is concerned about the falling numbers of rarer butterfly species
Richard Fox took this photo of a comma butterfly in 2025, but was disappointed by overall butterfly numbers
“We’ve lost variety and diversity”
Richard Fox, head of science at the East Lulworth based Butterfly Conservation, said:
“What this damning set of figures across the UK really shows us is what type of wildlife is able to survive in the UK’s modern landscapes, and it is not our wonderful specialist species – it is the generalists.
“Just as we have lost family run shops and traditional skills from the nation’s high streets, so we’ve lost variety and diversity in the butterfly communities that can exist in our damaged and simplified landscapes.
“We have some remarkable species in this country, and we know what we need to do to help them – create more habitat. That is what Butterfly Conservation has been doing for more than 50 years, but we are fighting an increasingly urgent battle and we need more help
“Last year’s sunny summer should have been amazing for butterflies, but we were not treated to a bumper butterfly year – indeed, more than one third of species had below average numbers.”
A pearl bordered fritillary, once widespread in Dorset but now mostly confined to Scotland
“Not insect Armageddon”
Richard Fox added:
“It’s not the insect Armageddon picture that was put forward a few years back, but the data show very clearly that butterflies have declined in the UK over the last 50 years, and in particular habitat specialist butterflies have declined.
“Butterfly Conservation can’t control the weather, but working with partners and landowners across the country we can improve the landscape.
“If we want to see our wonderful specialist species like the High Brown Fritillary, Northern Brown Argus and Duke of Burgundy recover from 50 years of decline, we need to restore as much of their precious habitat as we can – starting today.
“We have some remarkable species in this country, and we know what we need to do to help them – create more specialised habitats of the kind found across Purbeck.”
A silver studded blue butterfly at Studland
UK survey key facts
- Some of the biggest success stories in the past 50 years are the red admiral (numbers up 330 percent), the comma (up 178 percent) and the purple emperor (up 136 percent), which have moved further and further north due to warmer summers
- The largest increase of any species is the large blue, whose numbers have soared by 1,866 percent since 1983 – but that’s because, after being declared extinct in Britain in 1979, the butterfly has been successfully reintroduced
- Among the biggest losers are the white letter hairstreak (numbers down 80 percent), the pearl bordered fritillary (down 70 percent) and the high brown fritillary (down 66 percent) as their specialist habitats have shrunk
- The heathland dwelling silver studded blue butterfly has bucked the trend, but only thanks to intensive conservation efforts in places like Studland where a lot of the peninsula is managed by the National Trust
Dan Hoare of Butterfly Conservation has praised the volunteers who have collected data over the last 50 years
“There are winners and losers”
Dan Hoare, director of nature recovery at Butterfly Conservation based at East Lulworth said:
“Every year we have a couple of different ways of trying to take the temperature of the wildlife in the UK, the Big Butterfly Count is the easy way and we do that for a couple of weeks in the summer.
“The UKBMS is a dive into the deeper stats from an incredible band of volunteers who count butterflies every week right through the spring and summer and they have been doing that for a remarkable 50 years.
“More than 700,000 volunteers have been counting butterflies for us in this systematic way and that has produced this incredible data set which is the envy of the nature recording world, the biggest global database of insects anywhere .
“In the natural world, change is absolutely inevitable and there are winners and losers in the butterfly world, as you might expect.”
A jewel in the crown – the black hairstreak butterfly is now close to extinction in the UK
“The jewels in the crown”
Dan Hoare added:
“Butterflies respond very quickly to temperature changes year on year, and also to long term climate changes and to land use changes, the way we manage our farmland and woodland.
“We have the common species like red admirals that can live anywhere and are best able to take advantage of the modern world, but also those that are very specialist, the jewels in the crown of British wildlife, that are struggling the most.
“We do face a future in which some species are going to do well as our climate warms or as we reconfigure our countryside to new ways of managing the land.
“But we want as much diversity as possible because that gives us resilience, and the ability to respond – not just for butterflies, for all insects and plants because resilient ecosystems are one that can change and adapt, particularly with the speed of change that we now face.
“We need to redouble efforts to improve the state of farming and the state of the environment we live in and target conservation efforts for specialist habitats, that’s what will give us a really rich, diverse ecosystem that will allow us to thrive into the future.”
Insect expert Martin Warren has led butterfly counts at Studland for years
Further information
- All Dorset butterfly species are listed on the Butterfly Conservation website
- Read more on 2025 UK butterfly data
