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, by Lulworth-based charity Butterfly Conservation and the Centre for Ecology and Hydrology (CEH), found that 76 per cent of the UK’s resident and regular migrant butterflies have declined in abundance, occurrence or both over the last four decades.

A number of widespread species such as the Wall, Essex Skipper and Small Heath now rank among the most severely declining butterflies in Britain.

Richard Fox, lead report author and Butterfly Conservation’s head of recording, said: “Thanks to tens of thousands of people who help count butterflies in the UK each year, we have a clear picture of the changing fortunes of these captivating insects.

“Overall, the situation is stark. Most butterflies have decreased since the 1970s and an alarming number of common species have declined severely.

“On the other hand,” he added, “trends over the past decade provide grounds for optimism and show that our approach to conserving butterflies can stem and even reverse declines.”

Numbers of some of the most endangered butterflies, such as the Duke of Burgundy and the Pearl-bordered Fritillary, have increased during the last 10 years due to intensive conservation efforts.

The report also revealed more butterflies are reaching the UK from overseas. In the last few years, rare migrants like the Mediterranean Long-tailed Blue have emerged on the south coast in record numbers.

But despite breakthroughs with some threatened butterflies, other species continue to struggle. The decline of the Wood White, White Admiral and Marsh Fritillary shows few signs of stopping.

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 understood, but climate change and pesticides are thought to be contributing factors.

Chris Packham, vice-president of the Butterfly Conservation, 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.”

He added: “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.”