Threatened butterfly species cope well in below-average butterfly year

Threatened butterfly species cope well in below-average butterfly year - Butterfly Conservation

At a time when much of the natural world is in crisis, some butterfly species are showing signs of recovery, likely the result of concentrated conservation effort and positive land management.

Results from the annual UK Butterfly Monitoring Scheme (UKBMS) led by Butterfly Conservation, the UK Centre for Ecology & Hydrology (UKCEH), British Trust for Ornithology (BTO) and Joint Nature Conservation Committee (JNCC), show that while the overall picture for butterflies in 2021 was poor, species that are the focus of targeted conservation efforts have fared well.

After three good years in a row, 2021 was a below average year for UK butterflies, and the worst since 2017. Following one of the coldest and wettest Mays on record, especially in England and Wales, many common and widespread species did poorly. The Green-veined White had its fourth worst year on record and Large Skipper its fifth worst. The Common Blue, Large White, and Small Skipper also had a poor year, and even some widespread species that have shown long-term increases fared badly in 2021, with the Ringlet recording its lowest numbers since 2012.

However, despite the context of the generally poor year, there were some promising results for many threatened species. The endangered Heath Fritillary, which has been the focus of long-term intensive conservation efforts in Kent, Essex and Somerset had a good year and has now increased 112% at monitored sites in the last decade.

Butterfly Conservation’s Associate Director of Recording and Monitoring, Dr Richard Fox, explains: “We’re delighted to be seeing some positive signs for species such as the Heath Fritillary, especially when the general long-term picture for UK butterflies is one of great decline. It reinforces the importance of managing and restoring habitat in a way that supports the survival of our butterflies. While the Heath Fritillary remains a priority for conservation, these successes demonstrate what can be achieved through dedicated long-term conservation effort.”

The meticulously gathered UKBMS data show that 2021 was also a good year for the Silver-studded Blue, a butterfly that is classed as vulnerable in Britain. It is another species that has benefitted from much conservation work on its heathland and grassland habitats. 2021 was its best year since 1996 and its numbers have increased by 70% at monitored sites since the 1970s, with it having six above average years in a row.