Polychaete worm reefs on Atlantic sublittoral sediment
|Red List habitat type||code NEAA5.61|
|Source||European Red List habitat factsheet|
|European Red List of habitats reports|
|European Red List of habitats (Excel table)|
Sublittoral reefs of polychaete worms in mixed sediments are found in a variety of hydrographic conditions. Such habitats may range from extensive structures of tightly packed tubes to loose agglomerations of tubes. Patchiness can be a feature of this habitat with the reef structures interspersed with areas of sediment.They often play an important role in the structural composition or stability of the seabed and provide a wide range of niches for other species to inhabit. Consequently polychaete worm reefs often support a diverse flora and fauna. Three biotopes associated with this habitat have been described with different species of polychaete dominating: Sabellaria spinulosa on stable circalittoral mixed sediment, Sabellaria alveolata on variable salinity sublittoral mixed sediment and Serpula vermicularis reefs on very sheltered circalittoral muddy sand.
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.
The overall quality and continued occurrence of this habitat is, largely dependent on the presence of tubeworms which creates the biogenic structural complexity on which the characteristic associated communities depend. The density and the maintenance of a viable population of this species is a key indicator of habitat quality, together with the visual evidence of presence or absence of physical damage.
Synthesis of Red List assessment
While detailed, repeat assessments of S. spinulosa reef structures are rare S.spinulosa reefs are known to have been seriously degraded and reduced in the German Waddensea (by around 85%) over the last century. Over the last decade a further decline of around 33% is considered to have occurred. In the UK there are some localities where reefs are no longer present. Records indicate increases from the 1980's to the 2000's in the western North Sea with new reefs located off the southern North Sea in 2009. Trends in quality of subittoral S.alveolata reefs are also largely unknown whilst those of S.vermicularis appear to have shown substantial degradation. As the most abundant and extensive examples of this habitat are the reefs of S.spinulosa, the overall current trend in quantity and quality of this habitat is unknown.
Historical losses are known to have been substantial however it is not possible to determine whether these losses exceeded the threshold for Red Listing (loss of more than 40% of the extent of this habitat since 1750).
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 given the lack of information on its trends in quantity and quality and the fact that its overall distribution is unknown.
|Red List Category||Red List Criteria|
|Red List Category||Red List Criteria|
Confidence in the assessment
Pressures and threats
- Mining, extraction of materials and energy production
- Mining and quarrying
- Sand and gravel extraction
- Exploration and extraction of oil or gas
- Renewable abiotic energy use
- Transportation and service corridors
- Utility and service lines
- Biological resource use other than agriculture & forestry
- Fishing and harvesting aquatic resources
- Professional active fishing
- Benthic or demersal trawling
- Natural System modifications
- Human induced changes in hydraulic conditions
- Removal of sediments (mud...)
- Extraction of sea-floor and subsoil minerals (e.g. sand, gravel, rock, oil, gas)
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
- Restoring marine habitats
- 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
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|
|Greater North 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||174,236||52||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+||>52||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.|
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
|Species scientific name||English common name||Species group|
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||Reefs||1170||Narrower||http://ec.europa.eu/environm...rective/index_en.htm|