Kelp and seaweed communities in tide-swept sheltered Atlantic infralittoral rock
Quick facts
| Red List habitat type | code NEAA3.22 |
|---|---|
| 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 is a species-rich, structurally complex habitat that develops in areas of infralittoral rock sheltered from wave action but exposed to strong tidal streams such as the sheltered narrows and sills of Scottish sea lochs or in Norwegian fjords. In the sublittoral fringe dense Laminaria digitata is found together with erect seaweeds, sponges, ascidians and bryozoans. Below this, on bedrock and stable boulders a canopy of mixed kelp (primarily Laminaria hyperborea and Saccharina latissima) occurs with foliose red seaweeds, sponges and ascidians. In some situations, for examples on mixed substrata of boulders, cobbles, pebbles and gravel, there may be a reduced kelp canopy of L. hyperborea and S. latissima, but with a rich red seaweed component and maerl at some sites. Where the tide-swept rock occurs in estuarine conditions, the reduced and variable salinity as well as increased turbidity of the water has a significant effect on the biota, limiting the infralittoral zone to very shallow depths. The rock in these situations is characterised by a relatively low abundance of S. latissima with foliose red seaweeds, sponges and ascidians. L. hyperborea is rarely present.
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.
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 its area and 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
Pressures and threats
- Urbanisation, residential and commercial development
- Urbanised areas, human habitation
- Biological resource use other than agriculture & forestry
- Fishing and harvesting aquatic resources
- Natural System modifications
- Human induced changes in hydraulic conditions
- Modification of hydrographic functioning, general
- Modification of water flow (tidal & marine currents)
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 marine habitats
- Other marine-related measures
- Measures related to spatial planning
- Establish protected areas/sites
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 | ||||
| Macaronesia | ||||
| Kattegat |
Extent of Occurrence, Area of Occupancy and habitat area
| Extent of Occurrence (EOO) (Km2) | Area of Occupancy (AOO) | Current estimated Total Area | Comment | |
|---|---|---|---|---|
| EU28 | 1,161,730 | 57 | 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+ | >57 | 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).
