UK Butterfly Populations Face Potential Crash Due to Extreme Weather, Experts Warn
Despite a strong summer count, prolonged hot and dry conditions pose a significant threat to butterfly numbers, reminiscent of past ecological crises.
Butterfly and day-flying moth populations recorded in Devon and Cornwall this summer have been robust, but experts caution that prolonged hot and dry weather could lead to a significant decline. Nearly 5,000 participants in Devon's Big Butterfly Count recorded over 77,000 insects, while in Cornwall, close to 3,000 people spotted more than 47,000.
Professor Richard Fox, head of science at Butterfly Conservation, noted that while adult butterflies thrive in hot weather, the current climate trends could result in a population crash. He pointed to historical precedents, stating that extreme droughts in 1976 and 1995 had severe and lasting impacts on butterfly populations, with some species never fully recovering.
The strong numbers observed this summer are likely attributable to favorable conditions for caterpillars in the spring, followed by the recent warm weather that benefited adult butterflies. However, the charity expressed concern that preceding drought conditions across much of the UK may have withered food plants before caterpillars could finish feeding, with the full consequences potentially becoming clear next year.
Fox emphasized that many butterfly species are already under pressure, with an 80% decline in UK butterfly populations since the 1970s. "So many are already struggling for survival, without these extreme weather pressures," he stated. He warned that increasingly hot and dry summers, predicted to become more frequent due to climate change, could push already vulnerable species closer to extinction. "They are, quite simply, less resilient to these events, which means we could be looking at very difficult years ahead."
Butterfly Conservation is urging the public to support wildlife recovery by planting more trees and shrubs, installing water butts for rainwater storage, and leaving areas of grass uncut.
The Gatekeeper was the most frequently observed butterfly species in both Devon and Cornwall. In Devon, the Meadow Brown was the second most spotted, followed by the Red Admiral. Cornwall saw the Red Admiral in second place, with the Painted Lady ranking third.
The Painted Lady was a notable species, with 6,955 recorded in Devon and 6,033 in Cornwall. This migratory butterfly experienced a strong year nationally. Painted Ladies undertake a significant migration from Africa to the UK, crossing the Sahara Desert and Mediterranean Sea over multiple generations.
