Communities on Atlantic soft circalittoral rock
.jpg "European Red List of Habitats 2016")
.jpg "European Red List of Habitats 2016")
Quick facts
| Red List habitat type | code NEAA4.23 |
|---|---|
| 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 occurs on moderately wave-exposed, circalittoral soft rock such as soft chalk, clay or peat exposures, in areas subject to moderately strong tidal streams. As it is found in highly turbid water conditions it can be present in shallow water and sometimes even around the low water mark. The associated biotopes may therefore sometimes be present in the infralittoral and even the littoral zone. Soft chalk and firm clay are often too soft for sessile filter-feeding animals to attach and thrive in large numbers, so there is generally an extremely impoverished epifauna, particularly on upward-facing surfaces. The vertical rock faces may be somewhat richer. The rock is sufficiently soft to be bored by bivalves such as Pholas dactylus, and by polychaete worms Polydora sp. which may form a complete cover in highly turbid conditions. Carbonate cemented structures formed by methane seeps ('bubbling reefs') are also examples of this habitat. These have been reported from the northern Kattegat and the Skagerrak where they are present as slabs or pillars up to 4m high and are colonised by anthozoans Metridium senile, Alcyonium digitatum and Tealia felina as well as species which bore into the surfaces such as the
sponge Cliona celata, the polychaete Dodocaceria concharum and the bivalve Hiatella sp. The three dimensional structures also provides shelter for mobile species such as crabs and lobster, cod and pollack.
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 beendetermined and applied on a location-specific basis.
Threat status
Synthesis of Red List assessment
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 because of the lack of information on any trends in quantity and quality and the fact that its overall distribution is unknown.
| EU | |
| Red List Category | Red List Criteria |
| Data Deficient | - |
| Europe | |
| Red List Category | Red List Criteria |
| Data Deficient | |
Confidence in the assessment
Pressures and threats
- Transportation and service corridors
- Shipping lanes, ports, marine constructions
- 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...)
- Modification of hydrographic functioning, general
- Dykes, embankments, artificial beaches, general
- Sea defense or coast protection works, tidal barrages
- Climate change
- Changes in abiotic conditions
Habitat restoration potential
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
List of conservation and management needs
- 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
Distribution
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 |
| Celtic Seas | ||||
| Greater North Sea | ||||
| Kattegat | ||||
| Macaronesia |
Extent of Occurrence, Area of Occupancy and habitat area
| Extent of Occurrence (EOO) (Km2) | Area of Occupancy (AOO) | Current estimated Total Area | Comment | |
|---|---|---|---|---|
| EU28 | 597,111 | 63 | Unknown | EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the threshold for threatened status for EOO. |
| EU28+ | 63 | 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).
