Marsh fritillary butterfly
What action is going on for this species?
The Species Action Framework Lepidoptera project concluded at the end of March 2012. The final project report provides detail on the action taken for all three species covered under this project, including Marsh Fritillary.
The following will give you information on the work which took place through the Species Action Framework:
The marsh fritillary butterfly (Euphydryas (Eurodryas) aurinia) has a pale yellowish-brown upperside patterned with orange-brown markings and brown spots. The underside is light orange to brown with yellow spots. The caterpillars are black with black spines along the back.
Why is this on the Species Action List?
The marsh fritillary meets criterion 1a of the Species Action Framework, as a species for conservation action.
It has become extinct over a large part of its former range in the UK, having declined by about 60% since records began. The species continues to be vulnerable in many parts of its range and western Scotland now represents a stronghold.
Its management requirements are fairly well understood, and there are recognised agricultural practices that could benefit the butterfly and other wildlife which shares its habitat.
It is a UKBAP Priority Species and is included on the Scottish Biodiversity List. It is also included on Annex II of the EC Habitats Directive and is protected under the Wildlife and Countryside Act 1981, as amended.
Habitat, distribution and abundance
The marsh fritillary occurs in open grassland and, less frequently, in woodland clearings. The caterpillars feed on devil's bit scabious , although other plants such as field scabious and small scabious are occasionally used.
In Scotland most colonies are situated in areas of damp, neutral or acid grassland such as fen meadows and rush pastures, with abundant devil's bit scabious. Breeding areas are generally open, though many are sheltered either by scattered scrub or by adjacent woodland.
The marsh fritillary is distributed throughout western Europe and eastwards to Korea. However, it is declining in every European country. Western Scotland, in particular Argyll, is one of the species' remaining strongholds.
Continuous light grazing is required to produce a sward between 5 and 25cm high, although density of devil's bit scabious may be the key requirement. Most marsh fritillary colonies occur where there is light cattle or horse grazing. Sheep may preferentially graze scabious plants making them too short for the butterfly. Periodic scrub control may be needed on some sites to prevent invasion under low grazing levels, although scattered scrub provides shelter.
Usually the marsh fritillary is a sedentary species but some dispersal from colonies does occur. Populations can fluctuate greatly in size from year to year possibly because of weather conditions, food supply and caterpillar parasitism by braconid wasps of the genus Cotesia. Large fluctuations can cause local extinctions especially when butterfly populations are small and habitat patches are of low quality or not large enough.
The number of sightings of adults outside their breeding habitat suggests that marsh fritillary populations have a 'metapopulation' structure. This implies that the conservation of small sites, with populations that periodically become extinct, may be as important as the conservation of large sites.
History of decline, contributory factors and current threats
The UK is now believed to be one of its major European strongholds, but even here it has declined substantially over the last 150 years, due mostly to inappropriate management. The major threats to the marsh fritillary populations are habitat loss from land development and agricultural improvement, afforestation, changes in grazing regime, increasing fragmentation and isolation of habitats.
The 'Species Lead' at Scottish Natural Heritage
Brigid.email@example.com Tel 01463 725000