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
Prior to 1998 this small, unpigmented and eyeless ' well shrimp' was only known from Napp' s Cave, North Devon, and from twelve sites in South Devon (Knight, 2001). Here it occurs in a variety of freshwater habitats such as springs, wells, caves and mines. In 2000 it was discovered in an old well on a farm at Caer Bran, near Sancreed, in West Penwith. It has subsequently been found in another five sites in West Cornwall, all well sites. These discoveries represent the first occurrence of this apparently endemic species outside of Devon. It is likely that Niphargus glenniei is much more widespread in hypogean waters than previously assumed and that this small and unobtrusive species will be found in suitable habitats at other sites between West Cornwall (VC1) and the Devon border. It is believed that the true habitat of N. glenniei is channels of interstitial phreatic water in underground rock strata. Following heavy rain it is frequently washed out into stream and pools in caves, mines and, especially, wells. Pollution of groundwater is therefore a serious threat to this species, however the effects of pollutants, such as sewage and
fertiliser run-off, is not known. N. glenniei is a UK 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.