Polychaete/bivalve-dominated Atlantic littoral muddy sand
Quick facts
| Red List habitat type | code NEAA2.24 |
|---|---|
| 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 muddy or fine sand habitat often occurs as extensive intertidal flats on open coasts and in marine inlets. It is predominantly a habitat of the mid and lower shore though can span the entire intertidal. Where it occurs in marine inlets, the habitat may be subject to variable salinity conditions. Fine sand or mobile sand communities may be present on the upper shore with muddy sand communities present lower down. The sediment generally remains water-saturated during low water and has a high organic content resulting from settlement of organic detritus and growth of heterotrophic autotrophic micro-organisms. There is also typically a high microbial population and high sediment stability due to cohesion. An anoxic layer may be present below 5 cm of the sediment surface, sometimes seen in the worm casts on the surface.
Muddy sand habitats tend to support a relatively poor diversity of species, which are usually found in high abundances. These are predominately sessile tube-dwelling polychaetes with bivalves also well represented, amphipods and gastropods. Some species characteristic of subtidal areas may also occur. This habitat is also important for wintering and passage birds for feeding and roosting.
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 a lack of information on the area covered and on 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
- Discharges
- Biological resource use other than agriculture & forestry
- Fishing and harvesting aquatic resources
- Professional active fishing
- Benthic dredging
- Leisure fishing
- Bait digging / Collection
- Natural System modifications
- Human induced changes in hydraulic conditions
- Modification of hydrographic functioning, general
- Climate change
- Changes in abiotic conditions
- Wave exposure changes
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 wetland, freshwater and coastal habitats
- Restoring/Improving water quality
- Measures related to spatial planning
- Other marine-related measures
- Establish protected areas/sites
- Measures related to hunting, taking and fishing and species management
- Regulation/Management of fishery in marine and brackish systems
- Measures related to urban areas, industry, energy and transport
- Urban and industrial waste management
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 | 928,083 | 457 | 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+ | >457 | 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).
