Latest figures from the UK Butterfly Monitoring Scheme 

2 April 2013

Latest figures from the UK Butterfly Monitoring Scheme show that 2012 was the worst year for UK butterflies on record with 52 out of the 56 species monitored suffering declines.

Last year’s relentless rain and cold created disastrous conditions for summer-species in particular as they struggled to find food, shelter and mating opportunities; butterfly abundance plummeted to a record low as a result and 13 species suffered their worst year on record.

Some of our rarest species bore the brunt of the second wettest year on record. The critically endangered High Brown Fritillary fell by 46%, the vulnerable Marsh Fritillary was down 71% and the endangered Heath Fritillary saw its population plummet by 50% in comparison to 2011. In addition, many common species struggled. The widespread ‘Whites’ including Green-Veined White and the two 'Cabbage Whites', Large White and Small White saw their populations tumble by more than 50%. The alarming slide of garden favourite the Small Tortoiseshell continued with its population slipping 37% from 2011 figures.

Many of our most threatened butterflies were already in a state of long-term decline prior to the 2012 deluge. The recent series of wet summers has impacted on many species which were already suffering from widespread loss or fragmentation of suitable habitat.  There are now real fears that these already struggling species could become extinct in some parts of the UK as a result of last year’s wet weather.

Butterfly populations are used as indicators of environmental change, and are known to be strongly affected by land management practices, such as farming, forestry and building, in addition to the effects of weather and longer term climate change.

Data was gathered by the UK Butterfly Monitoring Scheme (UKBMS) jointly led by Butterfly Conservation and the Centre for Ecology & Hydrology (CEH) and funded by a multi-agency consortium including the Countryside Council for Wales, Defra, the Joint Nature Conservation Committee, Forestry Commission, Natural England, the Natural Environment Research Council and Scottish Natural Heritage. The UKBMS is indebted to all volunteers who contribute data to the scheme. UKBMS has run since 1976 and involves thousands of volunteers collecting data every week throughout the summer from more than 1,000 sites across the UK.

 

The full results for 2012 can be found on the UK Butterfly Monitoring Scheme website.