NORFOLK BIODIVERSITY ACTION PLAN SPECIES DATA AUDIT ...

ANNEX 6: TERRESTRIAL AND FRESHWATER INVERTEBRATES
TERRESTRIAL AND
FRESHWATER
INVERTEBRATES
Dragonflies, Crayfish
Anemone, Molluscs
etc.
Norfolk Hawker
Aeshna isosceles
Spp.
Considered
Extinct
Species Present
or
absent
in
White-clawed Crayfish
Austropotamobius pallipes
Large Dune Leafhopper
Doratura impudica
Lesser Water Measurer
Hydrometra gracilenta
Crystal Moss-animal
Lophopus crystallinus
Norfolk
Spp. New to
National
BAP List
No. of
records in
database
No. of 1km
squares
recorded
since 1980
Possible other sources
of data sets
25
Other survey
work completed
or in progress
Comments
P 96 47 County Recorder 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
P 226 100 River Glaven surveys
2006 and 2007; River
Thet surveys 2008.
Internationally threatened – Pollution, habitat degradation
and disease. Norfolk Action Plan published December 1998,
revised February 2002.
P? ? ? County Recorder 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
P 4 3 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.
P 5 5 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.