The State of the UK’s Butterflies 2015

Wall Brown
Wall Brown. Photo: Bob Eade

More than three-quarters of the UK’s butterflies have declined in the last 40 years with some common species suffering significant slumps, a major scientific study has revealed.

The State of the UK’s Butterflies 2015 report found that 76% of the UK’s resident and regular migrant butterflies declined in abundance, occurrence or both over the last four decades.

The report by Butterfly Conservation and the Centre for Ecology & Hydrology (CEH), found that a number of widespread species, including three that are found here in Dorset; the Wall, Essex Skipper and the Small Heath now rank amongst the most severely declining butterflies in the UK!

Duke of Burgundy

Duke of Burgundy. Photo: Iain H Leach

It’s not all doom and gloom however as it has been revealed that intensive conservation efforts have started to turn around the fortunes of some of the UK’s most endangered butterflies. During the last 10 years the numbers of the threatened Duke of Burgundy, a butterfly we have worked hard to preserve in the heart of Dorset, have increased by 67% and the Pearl-bordered Fritillary which despite becoming extinct from our county, has experienced a 45% rise in abundance nationally.

The report goes on to reveal that more butterflies are reaching the UK from overseas. Since the 1970s the three common migrant species – Clouded Yellow, Red Admiral and Painted Lady – have all increased dramatically in abundance.

The Dingy Skipper and Silver-studded Blue have shown 21% and 19% increases in occurrence respectively but despite breakthroughs with some threatened butterflies, the report revealed that other species continue to struggle. The long-term decline of the White Admiral, Marsh Fritillary and Wood White, which has sadly lead to the latter butterfly’s presumed extinction in Dorset, show few signs of stopping.

Wood White

Wood White. Photo: Iain H Leach

The report found that some once common and widespread species have become a cause for concern. The Wall, once a common farmland butterfly across southern Britain including Dorset, has suffered a 36% fall in occurrence and 25% drop in abundance since 2005, continuing a longer trend of decline. One of our most abundant species, the Gatekeeper, has experienced a 44% decline in abundance in the last decade and numbers of Small Skipper have been below average in every year of the 21st century.

The deterioration of suitable habitats due to agricultural intensification and changing woodland management are seen as major causes of the decline of butterflies that are habitat specialists. Decreases of butterflies found in the wider countryside are less well understood but climate change and pesticides may be playing a more harmful role in their declines than previously thought and remember there is still time to donate to Butterfly Conservation’s appeal for more research into pesticides and their impact on butterflies: 

Small Tortoiseshell

Small Tortoiseshell. Photo: Tim Melling

Butterfly Conservation Vice-president, Chris Packham, said: “As a society we are guilty of standing idly by as once common species, never mind the rarities, suffer staggering declines. This is a situation that should shame us all.

“The future of the UK’s butterflies does not have to be bleak. This report shows conservation work can and does turn around the fortunes of our most threatened butterflies.”

The report comes from data gathered by two long-running citizen science projects – Butterflies for the New Millennium (BNM) recording scheme and the UK Butterfly Monitoring Scheme (UKBMS). Read it in full here.

Leave a Reply