ARCHIVE: Observatory monitoring framework – indicator data sheet

Environmental impact: Biodiversity

Indicator DE6: Farmland butterfly populations

Butterflies are considered good biodiversity indicators because they respond rapidly to changes in environment and management, occur in a wide range of habitats (especially semi-natural habitats on farmland), and are representative of many other insects, which collectively account for more than 50% of terrestrial UK wildlife species.

This indicator is a multi-species index that has been compiled in conjunction with Butterfly Conservation (BC) and the Centre for Ecology and Hydrology (CEH) chiefly from data collated through the UK Butterfly Monitoring Scheme (UKBMS).

  • The overall population of 46 species of butterflies on farmland has fluctuated over the last 20 years with peaks at five to eight year intervals and a progressive decline in the intervening years. The annual fluctuations are due to natural environmental factors, especially weather conditions.

  • Though fluctuating markedly, the measures for both specialist and generalist species show an overall decline between 1990 and 2009. Analysis of the underlying smoothed trend shows the declines to be statistically significant, with an overall reduction in specialist species of 39% since the baseline (1990) and a 29% decrease from 2000-2009.

  • Generalist species have also declined over both reporting periods, with significant declines of 72% from 1990-2009 and 62% since 2000.

This indicator was updated in February 2011. A new monitoring scheme is currently under development. There is the potential to publish updates annually.

Further information and contact

Background information can be found in the accompanying fact sheet.

This is also a Biodiversity Strategy indicator.

For information on this indicator contact Defra's Observatory team on +44 (0) 1904 455229, email: observatory@defra.gsi.gov.uk

Fact Sheet | Printable Version (PDF) | Background Data (Excel)

Page last modified: 25 February, 2011
Page published: June, 2007

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