ANNEX 6: TERRESTRIAL AND FRESHWATER INVERTEBRATES
Spp. New to
Dragonflies, Crayfish Anemone, Molluscs etc.
TERRESTRIAL AN FRESHWATER INVERTEBRATES
Norfolk Hawker Aeshna isosceles
No. of 1km Possible other sources
squares recorded since 1980
of data sets
White-clawed Crayfish Austropotamobius pallipes
Large Dune Leafhopper Doratura impudica
Mole Cricket Gryllotalpa gryllotalpa
Lesser Water Measurer Hydrometra gracilenta
Crystal Moss-animal Lophopus crystallinus
Other survey work completed or in progress
River Glaven surveys 2006 and 2007; River Thet surveys 2008.
RDB Species Found on fen and grazing marsh dyke systems in Broadlands. Internationally threatened - Conversion of grazing marsh to arable farming, inappropriate ditch management, penetration of saltwater into grazing marshes, fluctuation in water levels, eutrophication and pollution. New to national list of BAP priority species 2007 Internationally threatened – Pollution, habitat degradation, invasive species and disease. Norfolk Action Plan published December 1998, revised February 2002. RDB Species Found on grasses on sand dunes. It was known in Britain only from the north Norfolk coast (Kirby 1992). Until it was collected in Essex by the P.R. Harvey at Colne Point and Crabknowe Spit in 1990 and 1991. Declining – Habitat loss and degradation. New to national list of BAP priority species 2007 Current SAP Declining – Agricultural intensification, drainage of arable areas, use of insecticides. The species is listed as Endangered in the GB Red List, and is protected under Schedule 5 of the WCA 1981. No modern Norfolk records. Current Species Statement. Found on the surface of small water bodies such as dykes or shallow pools with overhanging vegetation. The water bodies are usually situated in mature fen vegetation. Declining – Causes unclear. Current UK Species Action Plan Found in lakes, ponds, ditches and slow rivers. Marked decline in UK - Eutrophication of water bodies, water abstraction and over-tidying of water bodies, especially the removal of fallen wood.