Small Pearl-bordered fritillary

Durham Priority Species
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Small Pearl-bordered Fritillary Action Plan

Priority Species: Small Pearl-bordered Fritillary

Priorities 
1. Protect and enhance existing populations of the Small Pearl-bordered Fritillary in the DBAP area
2. Expand the range and size of population of Small Pearl-bordered fritillary
3. Maintain and enhance suitable habitat at known occupied sites and potential sites
4. Re-introduce Small Pearl-bordered Fritillary into its former areas

Targets
Vision Statement: To secure its remaining sites within the existing network, and to expand its range – including the restoration of other habitat networks within its former range.

Target Type Unit Value
1. To increase the range of the small pearl-bordered fritillary in the Durham BAP area. expand sites 10
2. To increase the population of small pearl-bordered fritillary in the Durham BAP area. expand number of colonies with more than 100 individuals 1

This butterfly occurs in four main habitats damp grassland, flushes and moorland; woodland glades and clearings; grassland with bracken and/or scrub; open wood-pasture and wood edges. Its larval food plants are marsh violet (Viola palustris)

The small pearl-bordered fritillary is single brooded with adults flying from late May to end of mid July

The butterfly remains widespread and locally abundant in Scotland & Wales, but has undergone severe decline in England, especially in central-southern England, surviving only in a dwindling number of woodland clearings.

Local status

In the North-east of England the small pearl-bordered fritillary is confined to violet-rich flushes, damp grassland and grassland/bracken/scrub mosaics.

By 2005, there were only four known extant small pearl-bordered fritillary colonies in the Durham BAP area, where the species has declined by at least 93% since the mid-nineteenth century. All four sites are located in the same habitat network. It is currently the most endangered butterfly species in the Durham area.  Extant sites support small populations (i.e. < 100 adults at peak flight period) and until recently, restricted to small breeding areas (<0.5ha), where larval food plants occur. All four sites are managed for the butterfly, but small patch size, small population size and isolation mean they are vulnerable (Ellis & Wainwright 2005). However, two more colonies were discovered in 2006 and it is possible other sites are awaiting discovery.

Threats

  • Loss of suitable habitat through inappropriate management of suitable habitat – i.e over or undergrazing.
  • Loss of suitable habitat through agricultural improvement – particularly through drainage, fertilisation and reseeding.
  • Isolation of remaining colonies
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