The development of butterfly indicators in the United Kingdom and assessments in 2010

The United Kingdom (UK) Government has national and international commitments to tackle the rate of biodiversity loss by 2010. Biodiversity indicators are used to measure and communicate progress in meeting these commitments. From 2005 onwards, butterflies have been adopted as Governmental biodiversity indicators in England, Scotland and for the UK as a whole. The indicators are compiled using butterfly abundance data collected through the UK Butterfly Monitoring Scheme, at a network of site established from 1976 onwards. The indicators show that butterfly numbers have fluctuated considerably from year-to-year, though analysis of the underlying smoothed multi-species trends for (habitat) ‘specialist’ species show significant long-term declines in each country since the 1970s. Trends in wider countryside ‘generalist’ species vary at the country-level from little or no overall change in Scotland and across the UK, to declines over selected years in England. Comparisons of changes in butterfly abundance before and after the 2010 target was set in 2002 suggest that the rate of decline at the UK-level is increasing for specialist species. In spite of large amounts of investment since 2000 to improve the habitat condition of protected areas, the trend for butterfly populations is no different in protected areas compared to elsewhere. Analysis by policy sector in England, shows that butterflies are declining rapidly in both forestry land and farmland, although in the latter habitat type, improvements are being seen on land entered into agri-environment schemes. We conclude by assessing the extent to which butterflies may represent broader biodiversity and help inform and evaluate conservation policy.