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No. of

No. of

Possible other

records in

1km

sources

database

squares

of data sets

Species

Present or absent in Norfolk

recorded since 1980

Mud Snail Omphiscola glabra (Lymnaea glabra)

P

1

1

Depressed River Mussel Pseudanodonta complanata

P

76

42

Other survey work completed or in progress

Comments

RDB Species Discovered in a pingo on East Walton Common. Typically found in acidic, nutrient poor water with little other aquatic life. Declining – Habitat loss but may be under- recorded. New to national list of BAP priority species 2007 Current UK Species Action Plan Occurs in lowland river, drains, canals and ditches. Described as declining nationally – Pollution and drought. Although this species is extending its range in the River Waveney. Norfolk Action Plan published December 1998, revised January 2003.

Species

Present or absent in Norfolk

Shining Ram’s-horn Snail Segmentina nitida

P

No. of

No. of

Possible other

records in

1km

sources

database

squares

of data sets

recorded

79

since 1980

17

58

Current UK Species Action Plan Found in unpolluted, usually calcareous water in the ponds and drains of grazing marshes. Declining – Causes unclear but believed to be over-frequent ditch clearance, eutrophication due to fertiliser run-off, and conversion of grazing levels to arable farming, with associated water table lowering. Norfolk Action Plan published December 1998, revised January 2003.

Other survey work completed or in progress

Comments

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Comments