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
In Britain, this species is at the extreme north-western limit of its range. It has healthy
populations in South West England, the West Wales littoral and around the New Forest. Cornwall is a particular stronghold.
The main populations in Cornwall are Bodmin Moor, the mid-Cornwall Moors and the tin streaming areas of Kerrier.
Habitat & Ecology
The species is typically associated with shallow, unshaded bog pools and slow flowing streams with conditions suitable for dense growth of Marsh St John' s-wort Hypericum elodes .
Continued landscaping or reclaimation of old mining sites in west Cornwall could remove suitable habitat in VC1. The routing of the new A30 across Goss Moor may have destroyed some sites in mid Cornwall.
Healthy populations remain in Cornwall, but monitoring needs to be maintained as the species is a ' key site' indicator.
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.