Seabed habitats and the communities of species that occupy
them are an essential component of the marine ecosystem and our
overall understanding of ecosystem function must relate seabed
habitats to hydrography, nutrient cycling, plankton changes and the
distribution of wide-ranging species (i.e. fish stocks, marine
mammals, birds). A greater understanding of the distribution,
extent and status or quality of marine habitats is required to
facilitate the protection of threatened and rare habitats and, more
generally, the assessment of the state of the marine environment.
Such information is also needed to improve spatial and strategic
planning of human activities, in particular to promote the wiser
use of habitats where there are competing demands (e.g. fishing,
sand and gravel extraction, wind energy generation, nature
conservation). As such, information on marine habitats needs to
play a major role in the ecosystem-based approach to management of
the marine environment that is now widely advocated at national and
international levels (Defra 2002; North Sea Conference 2002).
This habitat classification has, consequently, been developed
as a tool to aid the management and conservation of marine
habitats. It provides an ecologically-based classification of
seashore and seabed features, aimed primarily at classifying
benthic communities of invertebrates and seaweeds in a way which is
meaningful both to detailed scientific application and to the much
broader requirements for management of the marine environment. The
classification is relevant to the habitat requirements of more
mobile species, such as fish and marine mammals, but these are not
its primary focus. Whilst the corresponding European EUNIS
classification also includes water column (plankton) habitats, this
aspect has not yet been developed here.
The classification aims to provide comprehensive coverage, by
including habitats for artificial, polluted or barren areas as well
as more natural habitats, which encompass:
1. Marine, estuarine and brackish-water
(lagoon) habitats - It also includes reference to
saltmarsh habitats described in the National Vegetation
Classification (NVC) (Rodwell 2000; Doody, Johnston & Smith
1993) as these are regularly covered by the sea, and NVC types
which occur in brackish lagoons (Rodwell 1995).
2. Rock and sediment
habitats.
3. Upper shore to coastal waters
- From the supralittoral or splash zone and strand-line on the
shore out to the 200 nm limit. The habitats beyond the near-shore
subtidal zone (about the 3 mile/5 km limit) and below
about 50 m depth are less well described here, due to more limited
availability of data; more types will be defined as data become
available.
4. Plant and animal communities, including
epibiota and infauna - Types are defined using both their
fauna and flora. Most benthic marine habitats include sedentary
animals and small mobile animals which are an integral part of the
community, whilst in many habitats, especially in deeper water,
there are no plants (seaweeds or marine angiosperms) to
characterise the habitats. Sediment types are defined both by their
epibiota (surface-dwelling animals and plants) and their infauna
(animals living in the sediment).
5. Britain
and Ireland - It covers habitats
throughout Britain and Ireland and, through a widely-accepted broad
framework, is readily expandable to include offshore continental
shelf habitats and other areas in the north-east Atlantic,
Mediterranean and Baltic Seas. This is being achieved through the
EUNIS classification.