Polychaete/ bivalve-dominated mid-estuarine Atlantic littoral mud
Quick facts
Red List habitat type | code NEAA2.31 |
---|---|
Threat status | |
Europe | Endangered |
EU | Endangered |
Relation to |
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Source | European Red List habitat factsheet |
European Red List of habitats reports | |
European Red List of habitats (Excel table) |
Summary
Mid-estuarine shores of fine sediment, mostly in the silt and clay fraction though sandy mud (mostly very fine and fine sand) can also be a component of the substrate. Littoral mud typically forms extensive mudflats, though dry compacted mud can form steep and even vertical structures, particularly at the top of the shore adjacent to saltmarshes. Little oxygen penetrates these cohesive sediments, and an anoxic layer is often present within millimetres of the sediment surface. Most mid-estuarine muddy shores are subject to some freshwater influence, though at some locations more or less fully marine conditions may prevail. This habitat is mainly found along mid-estuarine shores and supports rich communities characterised by polychaetes, bivalves and oligochaetes. The mid-estuarine communities may also be present in sheltered inlets, straits and embayments which are not part of major estuarine systems, though there is usually some freshwater influence.
Indicators of quality:
Many indicators of quality have been used for this habitat with particular parameters 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. Indicators of quality of this habitat are frequently linked to those for the whole estuarine environment and therefore include morphological and physical characteristics, carrying capacity and water quality parameters. For the mudflat itself benthic indices, contaminant levels and productivity are some of the frequently used measures of quality.
Indices developed to assess the ecological status of coastal waters, including estuaries, according to the Water Framework Directive, include physical indicators, water quality indicators and measures of benthic diversity, species richness and abundance. The latter group, which is particularly relevant to benthic habitats, includes a Benthic Quality Index, an Infaunal Trophic Index, a Marine Biotic index based on ecological groups, and the Benthic Opportunistic Polychaetes/Amphipods index.
Threat status
Synthesis of Red List assessment
Because of the very substantial historical loss in quantity of this habitat, expert opinion is that this habitat should be assessed as Endangered for both the EU 28 and EU 28+.
EU | |
Red List Category | Red List Criteria |
Endangered | A3 |
Europe | |
Red List Category | Red List Criteria |
Endangered | A3 |
Confidence in the assessment
Pressures and threats
- Urbanisation, residential and commercial development
- Discharges
- Disposal of industrial waste
- Biological resource use other than agriculture & forestry
- Fishing and harvesting aquatic resources
- Professional active fishing
- Leisure fishing
- Bait digging / Collection
- Natural System modifications
- Human induced changes in hydraulic conditions
- Modification of hydrographic functioning, general
- Other ecosystem modifications
- Reduction or loss of specific habitat features
- Anthropogenic reduction of habitat connectivity
- Climate change
- Changes in abiotic conditions
- Changes in biotic conditions
Habitat restoration potential
Trends in extent |
|
Average current trend in quantity |
|
Stable ![]() |
Stable ![]() |
EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
Stable ![]() |
Stable ![]() |
EU28 | EU28+ |
Conservation and management needs
Spatial management including zoning of activities as part of Integrated Coastal Zone Management Schemes and Marine Protected Areas and controls of discharges throughout the watershed, are also beneficial as they facilitate management of the entire estuary complex.
List of conservation and management needs
- Measures related to wetland, freshwater and coastal habitats
- Restoring/Improving water quality
- Restoring/Improving the hydrological regime
- 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
- 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 | Stable | Stable |
Celtic Seas | ||||
Greater North Sea | ||||
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 | 630,325 | 201 | 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+ | >201 | 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).
Characteristic species
Species scientific name | English common name | Species group |
---|---|---|
Ulva lactuca | Algae | |
Arenicola marina | Invertebrates | |
Capitella capitata | Invertebrates | |
Cerastoderma edule | Invertebrates | |
Corophium volutator | Invertebrates | |
Crangon crangon | Invertebrates | |
Eteone longa | Invertebrates | |
Hydrobia ulvae | Invertebrates | |
Macoma balthica | Invertebrates | |
Mya arenaria | Invertebrates | |
Mytilus edulis | Invertebrates | |
Polydora cornuta | Invertebrates | |
Pygospio elegans | Invertebrates | |
Tubificoides benedii | Invertebrates |
Legal status
Relation to other habitat types mentioned in legal instruments
Legal text | Annex | Name in legal text | Code in legal text |
Habitat type relationship |
More information |
---|---|---|---|---|---|
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 | Estuaries | 1130 | Narrower | http://ec.europa.eu/environm...rective/index_en.htm |