Boloria euphrosyne

Range & Status

Widespread and locally abundant throughout Britain, but populations have declined by 51% over ten years to 2004 (Fox et al ., 2006). Widespread from northern Spain to Scandinavia and eastward to Russia and Asia. Said to be stable across Europe although declining in at least twelve countries (Asher et al ., 2001).

Regional Distribution

Once widespread, it is now comparatively rare in Cornwall (Wacher, Worth & Spalding, 2003) with possibly just seven colonies at Fellover Bridge, Bunny' s Hill, De Lank Quarry, Pendrift Downs, Millandreath, Marsland and Valency Valley. Recent records from the far west near Land' s End and St. Just have not been confirmed in follow up surveys and are not backed by historical records. Confirmation is needed from Treslea Downs where individuals were recorded in 2001 and 2005, and from the Rame Peninsula where the butterfly was seen in 2005 and 2007.

Habitat & Ecology

The females lay eggs on or near violets Viola spp. in dry, Bracken Pteridium aquilinum dominated habitats sheltered either by European Gorse Ulex europaeus , Sycamore Acer pseudoplatanus scrub or in rough grassland surrounded by woods. Larvae bask regularly on leaf litter and dead bracken.

Threats

Site management should aim to provide an ephemeral habitat. The cessation of grazing leads to excessive bracken litter and shading by scrub encroachment. Excessive grazing leads to the removal of all bracken litter and shelter.

Conservation

The continuance of light scrub clearance and agreed grazing regimes to maintain a mosaic of Violets, Bracken, dead leaf litter and shelter from scrub. It is possible that small colonies could still be found so recorders should be encouraged to examine Small Pearlbordered Fritillaries Boloria selene to confirm identifications. A UK BAP priority species.