Last summer marked the fifth worst period for butterflies in almost half a century across Britain, as highlighted by the world’s largest scientific survey of insect populations.
This marks the first time since recordings began in 1976 that more than half of Britain’s 59 native butterfly species have been in a state of long-term decline. Notably, nine species experienced their most challenging year on record, including the once-common small tortoiseshell, small copper, small skipper, large skipper, and green-veined white.
Dr. Richard Fox, the head of science at Butterfly Conservation, attributes the devastating decline of butterflies to human activities. He emphasizes that the destruction of wildlife habitats, environmental pollution, the extensive use of pesticides, and climate change are the primary factors. These actions leave butterfly populations vulnerable to adverse weather conditions and hinder their recovery.
Garden butterflies and those found in parks and the countryside also had their second-worst summer since 1976, with 51 out of 59 native species experiencing a decline compared to the previous year. While butterfly numbers naturally fluctuate due to Britain’s unpredictable climate, the data from the UK Butterfly Monitoring Scheme reveals that 31 native species are in a state of long-term decline.
The decline of the small tortoiseshell is particularly puzzling, as the butterfly was once abundant in gardens and its caterpillars feed on stinging nettles, a common plant. The small tortoiseshell had its worst year on record in 2023, followed by another decline the subsequent year.
Although conservationists have achieved notable successes in reviving critically endangered butterfly species, some species already listed as threatened in the UK experienced their worst years ever, including the grizzled skipper, small pearl-bordered fritillary, and chalkhill blue.
Butterfly Conservation is now advocating for reduced council grass-cutting and encouraging individuals to let their lawns grow longer to support butterflies and other insects. Research has shown that gardens with longer grass increase butterfly abundance and diversity. Dr. Fox emphasizes that creating more habitats is crucial to helping butterflies and urges people and councils across the UK to refrain from cutting their grass from April to September. This simple act can significantly benefit butterflies, moths, and other wildlife.
Source: https://www.theguardian.com/environment/2025/apr/02/last-summer-was-second-worst-for-common-uk-butterflies-since-1976
