LAST year's summer heatwave helped UK butterflies bounce back, a study has revealed.

More than two-thirds of UK butterfly species were seen in higher numbers than in 2017, with two of the UK’s rarest, the Large Blue and Black Hairstreak, recording their best years since records began, says the Lulworth-based Butterfly Conservation charity.

However, despite the upturn 2018 was still only an average year for the UK butterflies. Around two thirds of species continue to show an apparent decline since records began 43 years ago, according to the annual UK Butterfly Monitoring Scheme (UKBMS) led by Butterfly Conservation, the Centre for Ecology and Hydrology (CEH), British Trust for Ornithology (BTO) and Joint Nature Conservation Committee.

Species helped by last year's weather included the threatened Large Blue, with numbers up 58 per cent on the previous year, and the endangered Black Hairstreak Butterfly, which saw numbers shoot up by more then 900 per cent.

Butterfly Conservation associate director of monitoring Professor Tom Brereton said: "Last year brought some welcome relief for butterflies following five below average years in a row. But, there were not as many butterflies around as we might have expected given the fabulous weather over much of the butterfly season and overall 2018 ranked as barely better than average.

"This and the fact that two thirds of butterflies show negative trends over the long-term, highlights the scale of the challenge we face in restoring their fortunes and creating a healthier environment.

"It remains to be seen what the knock-on effects of the 2019 heatwave will be. We know that extreme events such as this, which are set to increase under climate change, are generally damaging to butterflies."

Meanwhile, Dr Mrc Botham, butterfly ecologist at the CEH, said: "The results show the positive impact that suitable weather conditions can have if there is suitable habitat in place for our butterflies to thrive.

"Thanks to ongoing habitat management, many of our threatened species can benefit from the good weather like that of summer 2018, but more still needs to be done to improve the condition of the wider countryside as a whole so other species can also take advantage.

"This can start in our own back gardens, by leaving areas un-mown and planting native wildflower species, for example."