Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA3.15 Frondose algal communities (other than kelp) on exposed Atlantic infralittoral rock

Frondose algal communities (other than kelp) on exposed Atlantic infralittoral rock

Quick facts

Red List habitat type code NEAA3.15
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 rocky habitat type is found in the infralittoral zone, in locations exposed or extremely exposed to wave action, or strong tidal streams. Associated biotopes are characterised by foliose red seaweeds, turfs of articulated Corallinaceae  and Cystosiera spp. at or below the lower limit of the kelp. Most of the red seaweeds which make up the dense turf of foliose red seaweeds are common to the kelp zone above, while the faunal component of the habitat is made up of species that are found either in the kelp zone or the animal-dominated upper circalittoral. Many of the red seaweeds, which occur in this habitat have annual fronds, which tend to die back in the autumn and regenerate again in the spring. This produces a seasonal change in the density of the seaweed cover, which is greatest between April and September, then substantially reduced over winter months. As well as a varied red seaweed component, this habitat may also contain occasional kelp plants and patches of the brown foliose seaweed Dictyota dichotoma

Dense fields of Cystoseira cf. abies-marina, are an associated biotope but currently only recorded on the Macaronesian archipelagos such as Formigas Bank, Azores and Chinijo Islets, north of Lanzarote, Canary Islands. Encrusting coralline algae frequently cover the substrate under the Cystoseira plants whilst Ulva rigida is an occasional epiphyte on the fronds. Around the various nooks and crevices of the irregular bedrock, the more abundant species are encrusting rhodophytes (calcareous and non-calcareous) as well as cartilagineous rhodophytes. Other species present are Sphaerococcus coronopifolius, Hypoglossum hypoglossoides, Dictyopteris membranacea and Cladophora sp.

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

Survey information confirms that this habitat has a widespread distribution in the North East Atlantic. It has been studied in detail in some localities however there is insufficient information to determine whether there have been any historical, recent and possible future trends in quantity or quality.
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 lack of information on its area and 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
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Nutrient enrichment (N, P, organic matter)
    • Marine water pollution
    • Oil spills in the sea
    • Toxic chemical discharge from material dumped at sea
    • Non-synthetic compound contamination
    • Synthetic compound contamination
  • Natural System modifications
    • Human induced changes in hydraulic conditions

Habitat restoration potential

Unknown

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

The main approach to the conservation and management of this habitat would be through regulation of activities that can alter the hydrological regime or sediment loads in the water column e.g.coastal and offshore construction. Water quality improvement programmes to reduce the risk of toxic contamination or of nutrient inputs leading to eutrophication would also be beneficial measures.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to marine habitats
    • Other marine-related measures
  • Measures related to spatial planning
    • Other marine-related measures
    • Establish protected areas/sites
  • Measures related to special resouce use
    • Regulating/Managing exploitation of natural resources on sea

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)
Bay of Biscay and the Iberian Coast Present Unknown Unknown Unknown
Celtic Seas
Greater North Sea
Macaronesia
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 2,094,000 83 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+ >83 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 Brongniartella byssoides
Algae Cryptopleura ramosa
Algae Delesseria sanguinea
Algae Dictyota dichotoma
Algae Dilsea carnosa
Algae Heterosiphonia plumosa
Algae Hypoglossum hypoglossoides
Algae Plocamium cartilagineum
Algae Sphaerococcus coronopifolius
Algae Ulva rigida
Fishes Centrolabrus trutta
Fishes Conger conger
Fishes Epinephelus marginatus
Fishes Phycis phycis
Fishes Thalassoma pavo
Invertebrates Alcyonium digitatum
Invertebrates Asterias rubens
Invertebrates Calliostoma zizyphinum
Invertebrates Cancer pagurus
Invertebrates Caryophyllia smithii
Invertebrates Clavelina lepadiformis
Invertebrates Cliona celata
Invertebrates Dysidea fragilis
Invertebrates Echinus esculentus
Invertebrates Electra pilosa
Invertebrates Esperiopsis fucorum
Invertebrates Marthasterias glacialis
Invertebrates Nemertesia antennina
Invertebrates Urticina felina
Species scientific name English common name Species group
Brongniartella byssoides Algae
Cryptopleura ramosa Algae
Delesseria sanguinea Algae
Dictyota dichotoma Algae
Dilsea carnosa Algae
Heterosiphonia plumosa Algae
Hypoglossum hypoglossoides Algae
Plocamium cartilagineum Algae
Sphaerococcus coronopifolius Algae
Ulva rigida Algae
Centrolabrus trutta Fishes
Conger conger Conger Fishes
Epinephelus marginatus Dusky grouper Fishes
Phycis phycis Forkbeard Fishes
Thalassoma pavo Ornate wrasse Fishes
Alcyonium digitatum Invertebrates
Asterias rubens Invertebrates
Calliostoma zizyphinum Invertebrates
Cancer pagurus Invertebrates
Caryophyllia smithii Invertebrates
Clavelina lepadiformis Invertebrates
Cliona celata Invertebrates
Dysidea fragilis Invertebrates
Echinus esculentus Invertebrates
Electra pilosa Invertebrates
Esperiopsis fucorum Invertebrates
Marthasterias glacialis Invertebrates
Nemertesia antennina Invertebrates
Urticina felina Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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