In particular, the small copper, which is found across Britain, had its worst year on record. Numbers fell by almost a quarter in comparison to 2014 figures.
The annual UK Butterfly Monitoring Scheme, led by Butterfly Conservation and the Centre for Ecology & Hydrology published its new figures for 2015 yesterday, in which it found that last year saw the coldest and wettest summer for three years – conditions that are not favourable to butterflies.
Other species also suffered. Heath fritillary numbers dropped by 16%, while the rare swallowtail suffered the largest decline of all, with numbers down 65% from the previous year.
However, some species did surprisingly well, with marbled white and brimstone experiencing their best years on record.
Dr Tom Brereton, Head of Monitoring at Butterfly Conservation, said: “In recent years it has become apparent that some of our most familiar and cherished butterflies are declining substantially.”
Changing environments and rapid habitat loss over the last century may also be contributing to these fluctuating figures, previous research has found.
The UKBMS has run since 1976 and involves thousands of volunteers collecting data through the summer. Last year a record 2,436 sites were monitored across the UK.