Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA1.45 Ephemeral green or red seaweeds (freshwater or sand-influenced) on Atlantic littoral non-mobile substrata

Ephemeral green or red seaweeds (freshwater or sand-influenced) on Atlantic littoral non-mobile substrata

Quick facts

Red List habitat type code NEAA1.45
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)

Summary

This habitat type occurs across the intertidal zone and sometimes in the splash zone, including on cliff faces in such locations. It may also be present on upper shore hard substrata that is relatively unstable (e.g. soft rock), or which is subject to considerable freshwater runoff. A dense mat of green filamentous algae, often together with some red algae, is a characteristic feature.

On moderately exposed shores, the biotopes 'Enteromorpha spp. on freshwater-influenced or unstable upper shore rock ' or 'P. purpurea and/or Enteromorpha spp. on sand-scoured mid- to lower-eulittoral rock'  may be present, both of which tend to support a low species diversity.

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.

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

Threat status

Synthesis of Red List assessment

This habitat has a large EOO and AOO, and therefore qualifies as Least Concern under criterion B. However the habitat is assessed as Data Deficient, both at the EU 28 and EU 28+ levels because of a lack of information on any trends in quantity and quality.
EU
Red List Category Red List Criteria
Data Deficient
Europe
Red List Category Red List Criteria
Data Deficient

Confidence in the assessment

low
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Pollution
    • Marine water pollution
    • Oil spills in the sea
    • Toxic chemical discharge from material dumped at sea
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Modification of hydrographic functioning, general
    • Dykes, embankments, artificial beaches, general
    • Sea defense or coast protection works, tidal barrages

Habitat restoration potential

Unknown, although the ephemeral nature and salinity tolerance of the characterising algal species suggests an ability to recover rapidly after damage if a suitable substrate is retained.

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

Beneficial management measures for this habitat include the regulation, zoning and limits on coastal development and on the construction of hard coastal defence structures where there is a risk of damage to the intertidal habitat. Water quality improvement programmes to reduce the risk of toxic contamination or of nutrient inputs leading to eutrophication would also benefit this habitat.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to spatial planning
    • Other marine-related measures
    • Establish protected areas/sites

Distribution

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)
Celtic Seas Present Unknown Unknown Unknown
Greater North Sea
Bay of Biscay and the Iberian Coast
Kattegat

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 319,776 205 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
EU28+ 205 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
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

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Algae Enteromorpha intestinalis
Algae Porphyra purpurea
Algae Rhodothamniella floridula
Algae Ulva lactuca
Invertebrates Carcinus maenas
Invertebrates Elminius modestus
Invertebrates Littorina littorea
Invertebrates Littorina saxatilis
Invertebrates Patella vulgata
Invertebrates Semibalanus balanoides
Species scientific name English common name Species group
Enteromorpha intestinalis Algae
Porphyra purpurea Algae
Rhodothamniella floridula Algae
Ulva lactuca Algae
Carcinus maenas Invertebrates
Elminius modestus Invertebrates
Littorina littorea Invertebrates
Littorina saxatilis Invertebrates
Patella vulgata Invertebrates
Semibalanus balanoides Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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