Annex I Sandbanks
Annex I Sandbanks which are slightly covered by sea water all
the time are elevated seabed features, consisting of sandy
sediments permanently covered by sea water. Water depth above the
top of sandbanks is seldom more than 20m below chart datum, but
some sandbanks, especially offshore examples may extend into
deeper waters. Sandbanks can be classified topographically (for
example, those associated with headlands, the open shelf or estuary
mouths) or by sediment type (for example, gravelly and clean sands,
or muddy sands). Shallow sandbanks may support vegetation, such as
eelgrass or maerl, but this is less common in offshore
waters.
Organisms found on and in shallow sandbanks include a variety
of worms, crustaceans, molluscs, urchins, starfish and crabs.
Sandy habitats can be important as nursery areas for a
variety of fish species. They also act as feeding grounds for
seabirds, seals and cetaceans, by providing a source of sandeels
and other prey species. Further information about
Annex I Sandbanks is provided on JNCC's website, and
the formal EU interpretation of this habitat is available in
the EU's
Interpretation
Manual of European Habitats.
Offshore sites should be selected to represent the main
variants of this habitat occurring offshore, having regard to
geographical range (Hopkins & Buck 1995). Offshore site
identification should also complement the shallow sandbank habitats
already represented within the SAC series inshore. On current
information, sites selected will encompass the following
topographical variants:
- Sandy mounds
-
The following tidal current sandbank types (Dyer &
Huntley 1999)
- Type 1 open shelf ridge sandbanks.
- Type 2 estuary mouth sandbanks.
- Type 3 headland associated banks.
Sites are also likely to be selected
to represent both 'active' and 'relict' banks (indicated by
sandwave presence and shape), as their flora and fauna are likely
to differ. Within the above categories, sites may also
be chosen to represent the biological communities of the range
of relevant sediment types (gravelly and clean sands, and muddy
sands). This Annex I habitat can include sandbank
features which extend below 20m water depth, according to the EU
Interpretation Manual.
Site boundaries are likely to
be drawn wider than the area of habitat (either singular or
multiple sandbanks) to take into account the conservation of the
structure and function of the habitat and also the mobile nature of
the habitat.
The map above represents areas of potential Annex
I sandbank habitat (areas of sandy sediment in less than 20 m
water depth using bathymetry calculated to the Lowest Astronomical
Tide datum). Through offshore biological and geomorphological
survey, JNCC is working to confirm Annex I sandbank presence
and identify those sites which merit selection as SACs. For
information on the identification of Annex I Sandbank
SACs within 12nm of the coast, please contact the relevant
country conservation agency.
If you would like information on the potential Annex I habitat
shapefiles please
contact our offshore survey team. These
shapefiles are subject to licencing agreements and therefore to
obtain them you will need to purchase licences for British
Geological Survey UK Seabed Sediments (DIG SBS 250K) and SeaZone
Bathymetry data either in the form of a SeaZone Hydrospaital or
SeaZone Bathymetry Topic layer.
References:
Dyer, KR & Huntley, DA (1999) The origin, classification and
modelling of sand banks and ridges. Continental Shelf
Research, 19, 1285-1330