Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA1.25 Seaweeds on moderately exposed shores

Seaweeds on moderately exposed shores

Quick facts

Red List habitat type code NEAA1.25
Threat status
Europe Data Deficient
EU Data Deficient
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This habitat is a calcareous turf on areas of intertidal rock exposed to wave action. It includes the biotope characterised by Chondracanthus acicularis which occurs on horizontal and vertical surfaces where it forms an extremely dense herbaceous stratum together with other species such as Chondracanthus teedei, Gelidium spinosum, Pterosiphonia complanata, Plocamium cartilagineum and Corallina elongata.These help prevent desiccation during the emersion periods. The fronds of the algae also provide habitat for several polychaetes, amphipods and molluscs.

Indicators of quality:

Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.

There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis.  Indicators which have been developed for the assessment of ecological quality of coastal water bodies for the Water Framework Directive (WFD) that are relevant to this habitat include a consideration of macroalgae species richness, proportions of different taxa of algae present, and the abundance and coverage of the rocky surfaces by typical species. 

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

There is a lack of information on the extent of this habitat and on any trends in quantity or quality over the last 50 years. For the purposes of Red List assessment it is therefore considered to be Data Deficient for both the EU 28 and EU 28+.
Red List Category Red List Criteria
Data Deficient -
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Human intrusions and disturbances
    • Other human intrusions and disturbances
    • Trampling, overuse

Habitat restoration potential


Trends in extent

Average current trend in quantity

Unknown Unknown
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

No specific management measures have been identified for this habitat due to a lack of information on potential pressures and threats.

List of conservation and management needs

  • No measures
    • No measure known / impossible to carry out specific measures


For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

Seas Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Bay of Biscay and the Iberian Coast Present Unknown Unknown Unknown

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 unknown unknown unknown Insufficient records for reliable estimate.
EU28+ unknown unknown Insufficient records for reliable estimate.
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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1050 Copenhagen K
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