Algal dominated communities in the Mediterranean circalittoral sediment
|Red List habitat type||code MEDA5.52A|
|Source||European Red List habitat factsheet|
|European Red List of habitats reports|
|European Red List of habitats (Excel table)|
Habitats formed in circalittoral sediments that usually have detritic components that allow erect macroalgae to grow over the seabed. The algal cover can be very variable, not always growing necessarily together with the maërl, and with a number of dominant species. They develop at low irradiances, usually between 5% and 0.5% of subsurface irradiance, at moderate to low hydrodynamism levels.
Several sub-habitats can be distinguished:
- Meadows of Osmundaria volubilis and Phyllophora crispa growing over detritic and gravel bottoms, between 50 and 90 meters depth. They can be very common in the central and North Western Mediterranean
- Kelp forests with Laminaria rodriguezii, below 70 meters depth and down to almost 100 meters depth from all the Mediterranean. This subhabitat can also grow shallower in special environmental conditions
- Kelp forests with Laminaria ochroleuca and Sacccorhiza polyschides, only in the Alboran Sea, northwestern coasts of Africa and the Strait of Messina, in places subjected to very strong currents.
- Beds of Halopteris filicina, between 55 and 100 meters depth.
- Gravel beds with Arthrocladia villosa and Sporochnus pedunculatus, between 30 and 50 meters depth.
- Gravel beds with Cystoseira spp.
Indicators of quality:
Habitat very variable according to several factors (nutrients, sedimentation, temperature, salinity, hydrodynamism) and to the main species dominating the assemblages. Some sub-habitats are rather constant through time (kelp habitats, Osmundaria volubilis) but others, like the subhabitat of Arthrocladia villosa and Sporochnus, are subjected to huge interannual variation in species composition and biomass.
Trends in abundance distribution and local species richness could be used as a proxy to examine quality overtime.The habitat can also change to non-native habitats dominated by two invasive species, Caulerpa cylindracea and C. taxifolia.
Synthesis of Red List assessment
The habitat has a large EOO and AOO. There are some cases of reported declines but overall trends are unknown and cannot be quanitified. This habitat has therefore been assessed as Data Deficient for both the EU 28 and EU 28+ .
|Red List Category||Red List Criteria|
|Red List Category||Red List Criteria|
Confidence in the assessment
Pressures and threats
- Urbanisation, residential and commercial development
- Urbanised areas, human habitation
- Biological resource use other than agriculture & forestry
- Intensive fish farming, intensification
- Suspension culture
- Benthic or demersal trawling
- Benthic dredging
- Invasive, other problematic species and genes
- Invasive non-native species
- Climate change
- Temperature changes (e.g. rise of temperature & extremes)
Habitat restoration potential
Trends in extent
Average current trend in quantity
Trends in quality
Average current trend in quality
Conservation and management needs
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
- Establish protected areas/sites
- Legal protection of habitats and species
- Measures related to hunting, taking and fishing and species management
- Regulation/Management of fishery in marine and brackish systems
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)|
|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||1,658,911||279||49,637||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+||624||61,180||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.|
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
Relation to other habitat types mentioned in legal instruments
|Legal text||Annex||Name in legal text||Code in legal text||
|Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora - consolidated version 01/01/2007||Annex I: natural habitat types of community interest whose conservation requires the designation of special areas of conservation||Large shallow inlets and bays||1160||Overlap||http://ec.europa.eu/environm...rective/index_en.htm|