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
This is a notable species that is declining nationally, but is locally widespread in England south-east of a line drawn between the Humber and the Bristol Channel. In Cornwall it occurs as an infrequent migrant and a very scarce resident.
Migrants tend to occur near, or along, valleys with a south facing aspect. The small breeding colony is confined to the Penhale Sands complex of coastal dunes where it was discovered in 1987. There was a 2005 record from Dozmary Pool on Bodmin Moor.
Habitat & Ecology
The Ruddy Darter prefers shallow, well vegetated ponds consisting of Bur-reed Sparganium spp. They also frequent lakes, canals and boggy pools. The fact that the species can remain as an egg for up to 160 days may explain its relative success in the ephemeral pools on Penhale Sands.
The species is vulnerable to excessive removal of emergent vegetation and long periods of drought that extend beyond the survival period of the egg without water.
This species is an Odonata Key Site indicator and, as a consequence, all breeding populations should be closely monitored. The Cornish site is an SSSI and is on the periphery of MOD controlled land.
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.