Polychaete/ oligochaete-dominated upper estuarine Atlantic littoral mud
.jpg "European Red List of Habitats 2016")
.jpg "European Red List of Habitats 2016")
Quick facts
| Red List habitat type | code NEAA2.32 |
|---|---|
| Threat status | |
| Europe | Endangered |
| EU | Endangered |
| Relation to |
|
| Source | European Red List habitat factsheet |
| European Red List of habitats reports | |
| European Red List of habitats (Excel table) |
Summary
Upper estuarine sandy mud and muddy shore communities, in areas with significant freshwater influence. The littoral mud typically forms 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.
The upper estuarine mud communities support few infaunal species and are principally characterised by a restricted range of polychaetes and oligochaetes. There are three oligochaete dominated upper estuarine mud biotopes associated with this habitat. Of these three, the biotope characterised by Nephtys hombergii and Streblospio shrubsolii occurs the furthest towards the mid estuary, and possibly lower on the shore than the other two. The biotope characterised by Tubificoides benedii and other is the most extreme upper estuarine biotope, occurring at the head of estuaries where there is no strong river flow and hence conditions are very sheltered, and there is a very strong freshwater influence. Further towards the mid estuary, this biotope may occur at the top of the shore.
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 under criterion A3 for both the EU 28 andEU 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
- Bait digging / Collection
- Pollution
- Marine water pollution
- Natural System modifications
- Human induced changes in hydraulic conditions
- Landfill, land reclamation and drying out, general
- Removal of sediments (mud...)
- Modification of hydrographic functioning, general
- Siltation rate changes, dumping, depositing of dredged deposits
- Dykes, embankments, artificial beaches, general
- Climate change
- Changes in abiotic conditions
- Flooding and rising precipitations
- Water flow changes (limnic, tidal and oceanic)
- Wave exposure changes
- Sea-level changes
- Changes in biotic conditions
- Habitat shifting and alteration
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
The water quality on mudflats has been regulated by a number of EC Directives including the the Urban Waste Water Treatment Directive, the Nitrates Directive and the Water Framework Directive. These commitments provide for the regulation of discharges to the sea and have set targets and quality standards covering many metals and pesticides, and other toxic persistent and bioaccumulative substances. National schemes, such as the Aquatic National Monitoring Programme in Denmark, provide data to indicate progress with implementation of such Directives.
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 marine habitats
- Other marine-related measures
- 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 | ||||
| Kattegat | ||||
| 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 | 271,876 | 106 | 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+ | >106 | 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
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 |
