Original Paper

Journal of Insect Conservation

, Volume 12, Issue 6, pp 629-638

First online:

The changing status of the Chalkhill Blue butterfly Polyommatus coridon in the UK: the impacts of conservation policies and environmental factors

  • Tom M. BreretonAffiliated withButterfly Conservation Email author 
  • , Martin S. WarrenAffiliated withButterfly Conservation
  • , David B. RoyAffiliated withNERC Centre for Ecology and Hydrology
  • , Katherine StewartAffiliated withButterfly ConservationPlantlife

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


The Chalkhill Blue Polyommatus coridon is a widespread butterfly of lowland calcareous grassland in southern Britain and is considered a good indicator of habitat condition. Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect. Analysis of annual butterfly monitoring data (transects) collected at 161 sites from 1981 to 2000 show a three-fold population recovery had occurred. The increases were at established sites, with no re-colonisations or range expansion detected. The 1980s population increase coincided with increases across the species range in stock and rabbit Oryctolagus cuniculus grazing, as well as greater protection and management of sites through protected areas and nature reserves. During the 1990s agri-environment schemes were thought to be the main conservation and policy mechanism driving the favourable conservation status of P. coridon, by facilitating appropriate habitat restoration and management. Weather played a part in the species recovery, with warm, but wet summers associated with increases in abundance. The research provides strong evidence of an important conservation success with the UK Biodiversity Action Plan, with implications for other specialist biodiversity.


Abundance trends Conservation policy Grazing Agri-environment schemes Biodiversity action plans Habitat condition