2012 a catastrophic year for UK butterflies

Of the 56 butterfly species monitored by the UK Butterfly Monitoring Scheme, 52 saw a fall in numbers from the previous year, with 13 experiencing their worst year since records began in 1976.

Heavy rain during the 2012’s washout summer meant that the butterflies struggled to find food and shelter, as well as mate successfully.

The most threatened species were already seeing long-term declines before last year’s record-breaking rainfall and experts are now warning that certain species could become extinct in some parts of the country.

Dr Tom Brereton, head of monitoring at Butterfly Conservation, said: “2012 was a catastrophic year for almost all of our butterflies, halting progress made through our conservation efforts in recent years.”

He added: “Butterflies have proved before that given favourable conditions and the availability of suitable habitat they can recover, but with numbers in almost three-quarters of UK species at a historically low ebb any tangible recovery will be more difficult than ever.”

The black hairstreak, one of the UK’s rarest species, saw numbers fall by 98 per cent, while other hairstreak species also fared badly. The green hairstreak population was down by more than two thirds and the white-letter hairstreak down 71 per cent.

Just four species saw an increase in numbers in 2012 compared with 2011, including the grass-feeding meadow brown whose numbers rose by a fifth. The Scotch Argus which thrives in damp conditions and saw numbers increase by 55 per cent.

The UK Butterfly Monitoring Scheme has run since 1976 and involves thousands of volunteers collecting data every week throughout the summer from more than 1,000 sites across the UK.