Changing climate could spell UK return for butterfly loved by Churchill
The changing climate means conditions in the UK may be suitable again for the return of one of Sir Winston Churchill's favourite butterflies, experts said.
The black-veined white butterfly was once found across southern England but became extinct in the UK in the mid-1920s, wildlife charity Butterfly Conservation said.
Changes in land use were a major factor in declining populations, and once numbers were at a low ebb, a few years of bad autumn weather were sufficient to finish off the species in the UK, the charity's Professor Tom Brereton said.
Sir Winston was a fan of the butterfly and attempted to release hundreds in the grounds of his Chartwell home in Kent in the mid-1940s, an activity that would be frowned upon today.
Studies have revealed that with climate change over recent decades, average conditions may now be more suitable for the black-veined white again, particularly in the warmer parts of southern and eastern England.
Though the butterfly can be found as far north as Scandinavia, it needs warm weather in late May and early June, with temperatures of 19C required for the adults to become really active, Prof Brereton said.
Two recent studies in parts of northern France that have a similar climate to southern England found it would be easy to recreate the habitat the butterflies need, by creating field margins rich in wildflowers and patches of scrub.
The results of the studies were revealed at Butterfly Conservation's international symposium in Southampton.
Fabrizia Ratto, from the University of Southampton, who conducted one of the studies, said: "Our study found that the butterfly has a strong preference for small isolated bushes of Blackthorn and Hawthorn as egg-laying sites with abundant nectar sources such as red clover nearby.
"These habitat conditions can be recreated relatively easily in the UK through the implementation of agri-environmental measures such as nectar flower mixes in crop margins and by allowing some scrub regeneration beside adjacent hedgerows."
Sir Winston is thought to have become a butterfly enthusiast during his time as a young officer stationed in India.
His plans to release the black-veined white were thwarted by his gardener who accidentally cut the nests of the young caterpillars from the hawthorn bushes where they had been carefully placed.
Before a modern attempt to reintroduce the species is made, more research is needed to see if conditions really are right for them, and whether they could withstand the increase in extreme weather events which are also the result of the UK's changing climate, Butterfly Conservation said.
In the last 150 years nearly 70 species of butterflies and moths have become extinct in the UK #ThursdayThoughts
The Black-veined White (Image by Adam Gor), is a butterfly that can still be found elsewhere in Europe but became extinct here in the British Isles around 1925. pic.twitter.com/2xlnIPlzdO
-- BC (@savebutterflies) February 15, 2018
But while climate change poses a threat to many UK species, the warmer average temperatures could provide an opportunity for the black-veined white, with a reintroduction a possibility in the future.
Prof Brereton, who is associate director of monitoring at Butterfly Conservation, said: "It would be great to have it back, it's one of the most spectacular butterflies."
Recreating the wildflower-rich margins and scrub the butterflies need could also help other wildlife such as bumblebees, he said.
"Creating habitat conditions for this butterfly would benefit pollinating insects and other valuable species, many of which are threatened by the impacts of climate change," he said.
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