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Species

Marsh Fritillary  (C) DWT

Marsh Fritillary

The Marsh Fritillary, Euphydryas aurinia, is a butterfly of the Nymphalidae family. As its name suggests, it is usually found in damp grasslands, but it is also found in other habitats such as heaths, neutral meadows and dry calcareous grasslands. The Marsh Fritillary has suffered massive declines in population numbers throughout the UK, and has been largely lost from eastern England and eastern Scotland. The butterfly’s range is now restricted to the west coast of Scotland, west Wales, Northern Ireland and south-west and central southern England. The deterioration in numbers is thought to have occurred largely as a result of a loss of suitable wet grassland sites and inappropriate management of existing habitats. Other influencing factors may include the recent wet summers, which hinder the butterfly’s ability to feed and reproduce, and the species is also susceptible to parasitism by a species of Apanteles wasp which targets the caterpillars and can severely deplete populations in some years.

Devon however remains a hotspot for the Marsh Fritillary, holding approximately 20% of known UK colonies (Devon BAP, 2009). The butterflies are very particular about where they lay their eggs and their larvae will only be found in areas which support the preferred food plant, devil’s-bit scabious. Where the habitat is too fragmented, populations are unable to persist, and so it is therefore essential to conserve a collection of high quality sites in close proximity to each other. In addition, it is important to ensure that these sites are well managed with open areas and shorter vegetation heights, as too dense grass and rush cover will likely deter Marsh Fritillaries from breeding.

Due to the threatened nature of culm grassland and the decline in Marsh Fritillary numbers it is crucial to monitor sites where they are known to be present, and also to look for them at potentially new locations where the habitat appears to be suitable. During the summer of 2013 Northern Devon NIA staff, with the great help of three placement students from Plymouth University, surveyed 30 sites and results show that the species appears to have had a good year; excitingly, Marsh Fritillaries were found at four new sites where they have not previously been recorded. All the results are sent to the Devon Biodiversity Records Centre and Butterfly Conservation, who collate the data and can then start to build up a better picture of how this rare and charming species is faring within the region.