Butterfly numbers are dropping but here are five species you may see more of
Butterfly Numbers Are Dropping, But Five Species May Be More Common
A half-century of warmer, sunnier conditions, partly fueled by climate change, has benefited certain British butterfly species. However, the overall trend paints a more concerning picture. Data from the UK Butterfly Monitoring Scheme (UKBMS) reveals that many of the UK’s most iconic butterflies are experiencing sharp population declines. This extensive dataset, spanning 1976 to the present, includes over 44 million records gathered by 782,000 volunteer surveys, making it one of the largest and most enduring citizen science initiatives of its kind.
Of the 59 native butterfly species tracked, 33 have seen population drops, while 25 have shown improvement. One mountain species remains unclassified due to insufficient data. Species thriving in this period include the Red admiral, which now winters in the UK as temperatures rise. Comma butterflies, noted for their frayed wing edges, have rebounded since the survey began. Orange tip populations have surged by over 40% since 1976, and the Black hairstreak—once among the UK’s rarest—has shown signs of recovery due to targeted conservation efforts.
Adaptability Shapes Survival Outcomes
Experts highlight a growing disparity between adaptable butterflies and those reliant on specialized habitats. Species that thrive across varied environments, such as farmland, parks, and gardens, tend to fare better. Warmer conditions linked to climate change are aiding this trend by enhancing survival rates and expanding breeding seasons. Prof Jane Hill of the University of York called the UKBMS dataset “extraordinary,” noting its status as a global benchmark for wildlife tracking. She explained that butterflies, being cold-blooded, respond favorably to milder temperatures, allowing some to push further north into Scotland and northern England.
“Most British butterflies reach their northern range limit in the UK, so they have opportunities to expand further north into northern England and Scotland,”
Yet species dependent on specific ecosystems, like woodland clearings or chalk grasslands, are struggling. These habitats are shrinking due to human activity, limiting the butterflies’ ability to relocate. The white-letter hairstreak, whose caterpillars emit a glow under UV light, has declined by 80% since the scheme began. The pearl-bordered fritillary, an orange-and-black butterfly feeding exclusively on violets, has also dropped by 70%.
Conservation Efforts and Challenges
Even among adaptable species, the outlook is mixed. The small tortoiseshell, once widespread, has declined by 87%. Prof Richard Fox of Butterfly Conservation emphasized the loss of diversity in butterfly communities. “Just as we have lost family-run shops and traditional skills from the nation’s high streets, we’ve lost variety and diversity in butterfly populations due to habitat simplification,” he stated.
“We’ve lost variety and diversity in the butterfly communities that can exist in our damaged and simplified landscapes,”
The scale of this dataset underscores the public’s dedication to monitoring wildlife. Volunteers have logged over 932,000 miles across more than 7,600 sites, enabling a detailed analysis of butterfly trends. Steve Wilkinson of the Joint Nature Conservation Committee noted the importance of this data. “Without this evidence timeline, we would be flying blind,” he said, stressing how volunteers’ consistency ensures informed conservation decisions.
Conservationists focus on preserving habitats, especially as land use changes accelerate. However, challenges persist because some butterflies depend on precise food sources. For example, the Duke of Burgundy relies solely on primroses and cowslips, while the purple emperor depends on goat or grey willow. Butterfly Conservation’s Magdalen Hill Downs reserve, which aims to maintain diverse habitats, exemplifies this effort.
