NORFOLK BIODIVERSITY ACTION PLAN SPECIES DATA AUDIT ...

Species Present
or
absent
in
Norfolk
Swollen Spire Snail
Mercuria similis (M. confusa)
Glutinous Snail
Myxas glutinosa
Mud Snail
Omphiscola glabra
(Lymnaea glabra)
Fine-lined Pea Mussel
Pisidium tenuilineatum
Depressed River Mussel
Pseudanodonta complanata
No. of
records in
database
No. of
1km
squares
recorded
since
1980
Possible other
sources
of data sets
57
Other survey
work
completed or
in progress
Comments
P ? ? County Recorder RDB Species
Found at Wheatfen Broad, Rockland Broad
and in the river Yare. It is also found in the
Waveney where it has extended its range.
Typically found on bare mud exposed at low
tide beneath emergent vegetation such as
Phragmites australis or Glyceria maxima.
Declining – Salinity changes, flood defence
works and climate change.
New to national list of BAP priority
species 2007
A 3 - Last Norfolk record in 1968. Considered
extinct in Norfolk.
Endangered. Current Species Action Plan
Occurs in clear, hard water which is free
from fine sediment and nitrate/phosphate
pollution.
Marked decline in UK – Disturbance and
pollution.
P 1 1 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 underrecorded.
New to national list of BAP priority
species 2007
A - - Not recorded in Norfolk
Current Species Action Plan
Found within many canal and river sites to
the north of London.
Declining – Causes unclear but probably
linked to declines in water quality. May be
under-recorded.
P 76 42 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.