The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Once widespread over Britain and Ireland the distribution rapidly declined during the nineties and is now restricted to southern and western areas in Britain and scattered across Ireland. The ten year population trend to 2004 shows a 73% decline (Fox et al ., 2006). It occurs from western Europe across Asia to Korea, but is declining in most European countries and is now extinct in the Netherlands (Asher et al ., 2001).
This butterfly is now restricted to three main areas: The Lizard heaths, mid-Cornwall moors and Bodmin Moor. The Mid-Cornwall Moors population have been the subject of a major LIFE fund initiative, with funding for detailed annual surveys and management; populations have generally been doing well here. There may still be colonies in the culm grassland areas of north Cornwall (the butterfly has been doing very well in similar habitat across the border in Devon) but no recent Cornish records are available. Searches by John Worth over the last five years of known sites in West Penwith appear to show that Marsh Fritillaries have disappeared from this area.
Habitat & Ecology
In Cornwall Marsh Fritillary favours open grassy areas in damp, unimproved meadows and heaths, especially where there is ample Devil' s-bit Scabious Succisa pratensis amongst grass tussocks (Wacher, Worth & Spalding, 2003). Exists in metapopulations, with local colonies that disperse in good years to nearby habitat patches within which periodic extinction and recolonisation occurs (Asher et al ., 2001).
Change of agricultural use by lack of grazing or overgrazing, drainage and application of fertiliser. Lack of grazing seems to be the biggest current threat although over grazing has caused the extinction on one site recently. Increased fragmentation and isolation of habitats.
Colonies occur on Goss Moor NNR, The Lizard Heaths NNR, Breney Common and Redmoor CWT nature reserves and the Windmill Farm joint CWT/CWBPS nature reserve. The Mid Cornwall Moors Life Project re-introduced burning and grazing to Goss Moor and to nearby sites in 2004. Sites on Goss Moor previously separated by the A30 highway have now been linked by the removal of the road from the Goss Moor National Nature Reserve as part of the programme to dual the A30 highway north of the reserve. A UK BAP priority species.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.