Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA3.1x Photophilic communities without canopy-forming algae in Mediterranean infralittoral and upper circalittoral rock

Photophilic communities without canopy-forming algae in Mediterranean infralittoral and upper circalittoral rock

Quick facts

Red List habitat type code MEDA3.1x
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 is present from the upper infralittoral zone to the upper circalittoral zone. Assemblages are always algal-dominated, although some invertebrates can be common in the understory and growing as epiphytes. It consists of rocky bottoms covered by erect macroalgae that do not form canopies. The structure includes bush-forming or turf forming algae, encrusting fauna and epiphytes. The coverage of the 'bush' and turf strata is usually higher than in an assemblage dominated by canopy algae. Assemblages are also highly miniaturized (less than 20 cm high) and very rich in species (up to 110 species in a 400 cm2 area).

Species composition differs greatly depending on environmental conditions. Factors accounting for the variability on the assemblages include light availability, hydrodynamism, nutrient concentration in the seawater, substrate type, sedimentation, temperature, salinity, grazing intensity, predation, and frequency of disturbances. High densities of sea urchins (Paracentrotus lividus) can graze the algae, producing structurally less complex assemblages and even barren areas. Grazing by other fish species (Sarpa salpa or the exotic Siganus rivulatus, S. luridus) can modify the species composition. The habitat can be present both in good environmental conditions, and in rather degraded situations. 

Several associated biotopes have been described, distinguished according to the dominant species. They include; Padina pavonica and similar species growing on well-lit shallow sheltered areas subjected to a moderate grazing by sea urchins; Pterothamnion crispum and Compsothamnion thuyoides growing on shallow, shaded sheltered to moderately exposed rocks; Corallina elongata growing on shallow exposed shores; Halopteris scoparia growing on well-lit sheltered areas down to 25 meters depth, mainly on northern areas, sometimes associated to the brown algae Cladostephus spongiosus; and Codium bursa on moderately lit infralittoral rock.

Indicators of quality:

This habitat is very variable according to the degree of anthropogenic disturbance. Indicators of quality can be measured by examining trends. The first signs of decline imply substitution of species, a decrease on diversity, an increase on invasive exotic species, and an increase in opportunistic, fast-growing species like some Ulva spp., Cladophora spp., Acinetospora spp., or stress resistant like Corallina elongata or Lithophyllum incrustans. Mussels can also replace the dominant algae in shallow waters when the charge of particulate organic matter is very high.

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

Threat status

Synthesis of Red List assessment

This is a widespread habitat in the Mediterranean Sea, however there is very little information available on its Area of Occupancy (AOO), impacts and trends in quantity and quality. Expert opinion is that the trends in quality are either stable or gradually decreasing but this cannot be quantified. Both quality and quantity decreases are expected to continue into the future.
The habitat has a large Extent of Occurrence (EOO) and AOO, and therefore it could potentially qualify as Least Concern under Criterion B but there is no information on any trends. However it has been assessed as Data Deficient for both the EU 28 and EU 28+ because of the 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

  • Urbanisation, residential and commercial development
    • Urbanised areas, human habitation
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Marine water pollution
  • Invasive, other problematic species and genes
    • Invasive non-native species
  • Natural biotic and abiotic processes (without catastrophes)
    • Species composition change (succession)
    • Accumulation of organic material
    • Eutrophication (natural)
  • Climate change
    • Temperature changes (e.g. rise of temperature & extremes)

Habitat restoration potential

Unknown. Examples of successful recovery of this habitat are rare for the Mediterranean and are linked to the presence of marine protected areas (MPAs). There is also large variation in the structure of these habitats. Therefore, the time lapse for recovery will be determined according to the different stressors, communities and conditions.

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. Its broad distribution suggests that it occurs in protected areas, however detailed information is missing. A wide survey to assess the habitat is needed in order to better evaluate its conservation status. Thereafter, the definition of sites for monitoring the habitat quality and quantity will help to conduct an assessment and identify appropriate management measures. These are likely to include improving water quality, Marine Protected Areas (MPAs) and regulation of fisheries.

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
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in marine and brackish systems
  • 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)
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 1,779,665 704 1,219 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+ >704 >1,219 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 Acinetospora crinita
Algae Alsidium corallinum
Algae Amphiroa rigida
Algae Arthrocladia villosa
Algae Asparagopsis armata
Algae Asparagopsis taxiformis
Algae Botryocladia botryoides
Algae Carpomitra costata
Algae Caulerpa prolifera
Algae Chondracanthus acicularis
Algae Chrysymenia ventricosa
Algae Chylocladia verticillata
Algae Cladophora prolifera
Algae Cladophoropsis membranacea
Algae Cladostephus spongiosus
Algae Codium bursa
Algae Colpomenia sinuosa
Algae Corallina elongata
Algae Dasycladus vermicularis
Algae Dictyopteris polypodioides
Algae Dictyota dichotoma
Algae Dictyota fasciola
Algae Dictyota mediterranea
Algae Dictyota spiralis
Algae Flabellia petiolata
Algae Gelidium spinosum
Algae Haliptilon virgatum
Algae Halopithys incurva
Algae Halopteris filicina
Algae Jania rubens
Algae Laurencia majuscula
Algae Laurencia obtusa
Algae Liagora distenta
Algae Liagora viscida
Algae Lithophyllum incrustans
Algae Lobophora variegata
Algae Lophocladia lallemandii
Algae Mesophyllum alternans
Algae Neogoniolithon brassica-florida
Algae Padina pavonica
Algae Peyssonnelia squamaria
Algae Plocamium cartilagineum
Algae Predaea ollivieri
Algae Pterocladiella capillacea
Algae Pterothamnion crispum
Algae Sphacelaria cirrosa
Algae Sphaerococcus coronopifolius
Algae Sporochnus pedunculatus
Algae Stypopodium schimperi
Algae Taonia atomaria
Algae Tricleocarpa fragilis
Algae Ulva rigida
Algae Wrangelia penicillata
Algae Zonaria tournefortii
Fishes Chromis chromis
Fishes Coris julis
Fishes Dentex dentex
Fishes Diplodus cervinus
Fishes Diplodus puntazzo
Fishes Diplodus sargus
Fishes Diplodus vulgaris
Fishes Epinephelus costae
Fishes Epinephelus marginatus
Fishes Labrus merula
Fishes Mullus surmuletus
Fishes Parablennius pilicornis
Fishes Sarpa salpa
Fishes Sciaena umbra
Fishes Scorpaena porcus
Fishes Serranus cabrilla
Fishes Serranus scriba
Fishes Siganus luridus
Fishes Siganus rivulatus
Fishes Sparisoma cretense
Fishes Symphodus mediterraneus
Fishes Symphodus ocellatus
Fishes Symphodus roissali
Fishes Symphodus tinca
Invertebrates Arbacia lixula
Invertebrates Bittium reticulatum
Invertebrates Columbella rustica
Invertebrates Crambe crambe
Invertebrates Digenea simplex
Invertebrates Hemimycale columella
Invertebrates Macropodia longirostris
Invertebrates Maja crispata
Invertebrates Marthasterias glacialis
Invertebrates Ophidiaster ophidianus
Invertebrates Ophiothrix fragilis
Invertebrates Paracentrotus lividus
Invertebrates Rissoa guerinii
Invertebrates Sarcotragus spinosulus
Species scientific name English common name Species group
Acetabularia acetabulum Algae
Acinetospora crinita Algae
Alsidium corallinum Algae
Amphiroa rigida Algae
Arthrocladia villosa Algae
Asparagopsis armata Algae
Asparagopsis taxiformis Algae
Botryocladia botryoides Algae
Carpomitra costata Algae
Caulerpa prolifera Algae
Chondracanthus acicularis Algae
Chrysymenia ventricosa Algae
Chylocladia verticillata Algae
Cladophora prolifera Algae
Cladophoropsis membranacea Algae
Cladostephus spongiosus Algae
Codium bursa Algae
Colpomenia sinuosa Algae
Corallina elongata Algae
Dasycladus vermicularis Algae
Dictyopteris polypodioides Algae
Dictyota dichotoma Algae
Dictyota fasciola Algae
Dictyota mediterranea Algae
Dictyota spiralis Algae
Flabellia petiolata Algae
Gelidium spinosum Algae
Haliptilon virgatum Algae
Halopithys incurva Algae
Halopteris filicina Algae
Jania rubens Algae
Laurencia majuscula Algae
Laurencia obtusa Algae
Liagora distenta Algae
Liagora viscida Algae
Lithophyllum incrustans Algae
Lobophora variegata Algae
Lophocladia lallemandii Algae
Mesophyllum alternans Algae
Neogoniolithon brassica-florida Algae
Padina pavonica Algae
Peyssonnelia squamaria Algae
Plocamium cartilagineum Algae
Predaea ollivieri Algae
Pterocladiella capillacea Algae
Pterothamnion crispum Algae
Sphacelaria cirrosa Algae
Sphaerococcus coronopifolius Algae
Sporochnus pedunculatus Algae
Stypopodium schimperi Algae
Taonia atomaria Algae
Tricleocarpa fragilis Algae
Ulva rigida Algae
Wrangelia penicillata Algae
Zonaria tournefortii Algae
Chromis chromis Damselfish Fishes
Coris julis African rainbow wrasse Fishes
Dentex dentex Common dentex Fishes
Diplodus cervinus Zebra seabream Fishes
Diplodus puntazzo Sharpsnout sea bream Fishes
Diplodus sargus Fishes
Diplodus vulgaris Common two-banded seabream Fishes
Epinephelus costae Goldblotch grouper Fishes
Epinephelus marginatus Dusky grouper Fishes
Labrus merula Brown wrasse Fishes
Mullus surmuletus Red mullet Fishes
Parablennius pilicornis Fishes
Sarpa salpa Gold line Fishes
Sciaena umbra Brown meagre Fishes
Scorpaena porcus Black scorpionfish Fishes
Serranus cabrilla Comber Fishes
Serranus scriba Painted comber Fishes
Siganus luridus Dusky spinefoot Fishes
Siganus rivulatus Marbled spinefoot Fishes
Sparisoma cretense Fishes
Symphodus mediterraneus Axillary wrasse Fishes
Symphodus ocellatus Fishes
Symphodus roissali Five-spotted wrasse Fishes
Symphodus tinca East Atlantic peacock wrasse Fishes
Arbacia lixula Invertebrates
Bittium reticulatum Invertebrates
Columbella rustica Invertebrates
Crambe crambe Invertebrates
Digenea simplex Invertebrates
Hemimycale columella Invertebrates
Macropodia longirostris Invertebrates
Maja crispata Invertebrates
Marthasterias glacialis Invertebrates
Ophidiaster ophidianus Invertebrates
Ophiothrix fragilis Invertebrates
Paracentrotus lividus Invertebrates
Rissoa guerinii Invertebrates
Sarcotragus spinosulus Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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