Survey of Marsh Fritillary and Rare Bumblebees in Annex I Grassland Habitats

Funded by: The Heritage Council

During 2010, BEC Consultants conducted a survey of butterflies and bumblebees across Counties Cavan, Leitrim, Roscommon and Offaly. Data from the Irish Semi-natural Grasslands Survey, which was funded by the National Parks and Wildlife Service, were used to locate sites that would potentially contain suitable habitat. Two types of grassland habitat that are protected under Annex I of the EU Habitats Directive were specifically targeted, because the occurrence of the marsh fritillary butterfly (Eurodryas aurinia) has been associated with these habitats:

  • Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia) (* important orchid sites) (6210)
  • Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae) (6410)

Sixteen sites were surveyed across the four counties, with additional data being collected for a site that was already managed for the marsh fritillary by Butterfly Conservation Ireland and the Irish Peatland Conservation Council in Co. Kildare.

Two new sites for the marsh fritillary were discovered in Co. Roscommon and several other scarce butterflies and bumblebees were recorded, including one record of the vulnerable Bombus ruderarius.  Data on the habitat suitability for the marsh fritillary were also collected at each site.  The marsh fritillary is known to require a network of suitable habitats, so such data will be of value to any further projects that seek to survey or manage the marsh fritillary in these counties.

Emphasis was placed on the marsh fritillary, as of the three Irish butterfly species listed as vulnerable on the Irish Red Data List, it is the only one protected under Annex II of the EU Habitats Directive.  Its numbers have declined severely throughout Europe; and Britain and Ireland are believed to be major European strongholds for the species.  Declines have been attributed to loss of uncultivated grasslands, overgrazing on remaining habitat and its requirement for extensive habitat area and wildlife corridors.

Dingy Skipper (Erynnis tages), photo by Kate McNutt

Marsh fritillary (Euphydras aurinia) larvae, photo by Kate McNutt

Small copper (Lycaena phlaeas), photo by Kate McNutt

Other Marsh Fritillary surveys conducted by BEC Consultants include a Marsh Fritillary Survey of Louth, Meath and Monaghan and the Galway City Outer Bypass Marsh Fritillary Survey, both undertaken in 2013.