Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA3.23 Photophilic communities dominated by calcareous, habitat-forming algae

Photophilic communities dominated by calcareous, habitat-forming algae

Quick facts

Red List habitat type code MEDA3.23
Threat status
Europe Vulnerable
EU Vulnerable
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)

Summary

This habitat occurs in shallow rocky bottoms with large coverage of calcareous, habitat-forming corallines that provide a persistent biogenic structure. It develops on vertical cliffs in well exposed and illuminated conditions. Two red algae species dominate this habitat: Titanoderma trochanter and Tenarea tortuosa. Both species can occur together. Erect macroalgae grow interspersed with the corallines. They grow in places with a good water quality, a moderate to low hydrodynamism, and above 1.5 meters depth.

Indicators of quality:                                                                                                                              

There is no information on indicators of quality. Both dominant species seem to be restricted to environments with a good water quality although no quantitative explorations have been performed on this issue to ascertain also what might be indicators for quality assessment.

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

Threat status

Synthesis of Red List assessment

Although this habitat has a wide geographic distribution, it is present in only relatively small areas. Given its vulnerability to climate change and sea level rise, there is a threatening process that is likely to cause a continuing decline in the quantity and/or quality within the next 20 years. This will affect the habitat over its whole distribution in the Mediterranean although it is uncertain if some areas will be more resilient than others. This habitat has therefore been assessed as Vulnerable for both the EU 28 and EU 28+.
EU
Red List Category Red List Criteria
Vulnerable B2b
Europe
Red List Category Red List Criteria
Vulnerable B2b

Confidence in the assessment

low
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Biological resource use other than agriculture & forestry
    • Removal for collection purposes
  • Human intrusions and disturbances
    • Trampling, overuse
  • Climate change
    • pH-changes
    • Sea-level changes

Habitat restoration potential

Unknown. The rims formed by some of these species only adhere to the substrate at a few points and are easily detached or be broken off by hand. Therefore its recovery capacity will depends on the building of the structure.

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

Currently, there are no specific conservation actions in place for this habitat.This habitat would benefit from measures to improve the water quality, prevention of removal as souvenirs and establishment of protected areas.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to spatial planning
    • 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)
Adriatic Sea Present Unknown Unknown Unknown
Aegian-Levantine Sea
Ionian Sea and the Central Mediterranean Sea
Western Mediterranean Sea

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 1,249,443 33 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+ 35 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 Acetabularia acetabulum
Algae Amphiroa rigida
Algae Anadyomene stellata
Algae Cystoseira barbatula
Algae Cystoseira compressa
Algae Cystoseira crinita
Algae Dictyota fasciola
Algae Haliptilon virgatum
Algae Jania rubens
Algae Laurencia obtusa
Algae Lithophyllum incrustans
Algae Neogoniolithon brassica-florida
Algae Padina pavonica
Algae Tenarea tortuosa
Algae Titanoderma trochanter
Fishes Parablennius gattorugine
Fishes Parablennius incognitus
Fishes Sarpa salpa
Fishes Siganus luridus
Invertebrates Dendropoma petraeum
Species scientific name English common name Species group
Acetabularia acetabulum Algae
Amphiroa rigida Algae
Anadyomene stellata Algae
Cystoseira barbatula Algae
Cystoseira compressa Algae
Cystoseira crinita Algae
Dictyota fasciola Algae
Haliptilon virgatum Algae
Jania rubens Algae
Laurencia obtusa Algae
Lithophyllum incrustans Algae
Neogoniolithon brassica-florida Algae
Padina pavonica Algae
Tenarea tortuosa Algae
Titanoderma trochanter Algae
Parablennius gattorugine Tompot blenny Fishes
Parablennius incognitus Fishes
Sarpa salpa Gold line Fishes
Siganus luridus Dusky spinefoot Fishes
Dendropoma petraeum Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100