Macaronesian submerged fucoids, green or red seaweeds on full salinity infralittoral rock

This habitat is found throughout the Macaronesian islands in rocky infralittoral areas and is characterised by the presence of many photophilic algae.

In shallow waters 2-3m around the Azores the habitat is dominated by Codium fragile although in places the invasive species C. fragile spp. tomentosoides has also become established.  In the southern Macaronesian archipelagos of Madeira, Selvagen and the Canaries other Codium  spp. are characteristic elements of this habitat either as conspicuous narrow belt of crustose species (C. intertextum, C. adhaerens) in the infralittoral fringe, globlose to subglobose, somewhat flattened specimens of C. elisabethiae / C. bursa, or frondose and large specimens in crevices and overhangs (C. taylorii) or attached to pebbles (C. decorticatum).

In shallow sublittoral rocks, it is also possible to find the biotope of the green macroalgae Dasycladus vermicularis - Halimeda discoidea -Acetabularia acetabulum  with the gasteropod Elysia timida.  Where there is some organic matter sedimentation the red algae Halopithys incurva, Digenea simplex, Rytiphlaea tinctoria and Alsidium corallinum are more common.

The fucoids Cystoseira mauritanica, C. tamariscifolia  and sometimes, C. abies-marina and c. foeniculacea, Sargassum vulgare - S. desfontainesii - S. furcatum are the main elements of other biotopes, with many marine invertebrates associated (copepods, amphipods, hydrozoans, etc.). A seasonal biotope during spring – summer months is characterized by Sporochnus spp.

In deeper waters with low light intensity the associated biotopes include those characterised by the red macroalgae Botryocladia, Halymenia, Sebdenia and less frequently Kallymenia.  In some detritic sediments, the introduced tropical green seaweed Caulerpa racemosa  var. cylindracea  could be observed between 10 - 50 m. depth. Associated species are the polychaete Ditrupa arietina, decapods such as Paromola cuvieri and Cancer bellianus, bryozoans of the genus Cupuladria and the sea urchins Cidaris cidaris and Genocidaris maculata.

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:

In the Canary Islands, common associated species are the anthozoan Palythoa canariensis and the bivalve Spondylus senegalensis as well as the red macroalgae Nemastoma canariensis and the esponges Aplysina aerophoba e Ircinia spp. The Azores archipelago is the southwestern limit of distribution of Codium fragile ssp. atlanticum but the invasive species C. fragile ssp. tomentosoides has also established successful populations in the archipelago.  

The biodiversity of these biotopes is high, with the dominant macroalgal species associated with other macroalgae, such as the perennial species Halopteris scoparia  Cladostephus spongiosus and Padina pavonica or the annual  green macroalgae Acetabularia acetabulum. Among these species it is possible to observe turf species, such as Ellisondia elongata  Jania rubens, Jania corniculata or Haliptilon virgatum, Amphiroa rigida, erect species such as Liagora distenta, Hypnea musciformis, H. cervicornis, or epiphytes as Falkenbergia rufolanosa. Among gastropod molluscs, Haliotis tuberculata, Gibbula  spp., Rissoa  spp., Aplysia  spp., Elysia timida, Ocenebra erinacea, Ocinebrina edwardsi, Stramonita haemastoma and Nassarius incrassatus are observed. The most common echinoderms are Sphaerechinus granularis, Paracentrotus lividus and Arbacia lixula (sometimes also the long spined sea urchin Diadema africanum) and the seastar Echinaster sepositus. The icthyofauna is diverse and common species are Sparus aurata, Sciaena umbra, Ephinephelus marginatus and Hippocampus hipppocampus.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats