Atlantic lower circalittoral sand
Quick facts
| Red List habitat type | code NEAA5.27 |
|---|---|
| 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
This habitat occurs in offshore circalittoral habitats with fine sands or non-cohesive muddy sands. They include areas in the Celtic Sea and areas of the Irish Sea, north of the Isle of Man, in Liverpool Bay and Cardigan Bay and also in St. George’s Channel. The sediments are likely to be more stable than similar shallower counterparts and the associated communities are characterised by a diverse range of polychaetes, crustaceans, bivalves and echinoderms. In deep offshore sand or non-cohesive muddy sand dense populations of maldanid polychaetes such as Maldane sarsi as well as the cumacean Eudorellopsis deformis may be found. Accompanying these species are abundant ophiuroids, the amphipod Harpinia antennaria and the bivalves Nuculoma tenuis and Parvicardium minimum. Areas of slightly muddy sand may be characterised by high numbers of the tube building polychaete Owenia fusiformis often with the brittlestar Amphiura filiformis.
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.
Examples of indicators of "naturalness" that are potential indicators of quality for offshore sand habitats such as this are; typical populations of bivalves and epifaunal brittlestars; maintained presence of substratum; lack of smothering; typically diverse communities with no increase in hardy or opportunistic species; and maintenance of sediment characteristics with typical levels of diversity.
Threat status
Synthesis of Red List assessment
Most sedimentary benthic systems on the continental shelf of Europe have been modified by fishing activities in the last 100 years, particularly by mobile demersal gears, and this habitat remains under fishing pressure. Disturbance of the substratum due to intensive fishing activities using bottom trawls or dredges can damage or modify infaunal communities, with burrowing echinoderms and bivalves being particularly vulnerable. Loss of substrate is also likely to be detrimental particularly where the majority of the characterising species are interstitial polychaetes. Recent data for a single year (2013/2014) has revealed that over 80% of the estimated area of lower circalittoral sand habitat in the North Sea and Celtic Sea was subject to to fishing pressure by bottom otter, beam and mid-water trawls. Much the same footprint of activity is likely each year and as this type of fishing pressure has been ongoing for many decades, there has most likely been a cumulative impact on habitat quality.
Expert opinion is that there has been a very substantial reduction in quality of this habitat, most likely an intermediate decline affecting more than 80% of its extent although it is clear that in some locations there has also been a severe decline. The severity will depend on factors such as the intensity and frequency of disturbance. This habitat has therefore been assessed as Endangered for both the EU 28 and EU 28+ because of both past and likely continuing declines in quality.
| EU | |
| Red List Category | Red List Criteria |
| Endangered | C/D1 |
| Europe | |
| Red List Category | Red List Criteria |
| Endangered | C/D1 |
Confidence in the assessment
Pressures and threats
- Biological resource use other than agriculture & forestry
- Fishing and harvesting aquatic resources
- Professional active fishing
- Benthic or demersal trawling
- Benthic dredging
- Pollution
- Pollution to surface waters (limnic, terrestrial, marine & brackish)
- Nutrient enrichment (N, P, organic matter)
- Marine water pollution
- Toxic chemical discharge from material dumped at sea
- Synthetic compound contamination
- Climate change
- Changes in abiotic conditions
- Water flow changes (limnic, tidal and oceanic)
- Wave exposure changes
Habitat restoration potential
Thyasirids, small burrowing bivalves which live in fine sediments, are thought to be fairly slow growing and recovery of a damaged population is likely to take up to 5 years and depends on direct recruitment from the same population due to the low dispersal potential of these species. Where they occur in isolated poulations they are therefore unlikely to recover if lost. In comparison, the high fecundity and larval dispersal potential of many of the polychaetes associated with this habitat is likely to result in a population recovering quite quickly - in less than a year for O. fusiformis and in approximately 5-6 years for A. filiformis due to the later age at which it reaches sexual maturity
Trends in extent |
|
Average current trend in quantity |
|
Unknown  |
Unknown |
| EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
Decreasing  |
Decreasing |
| EU28 | EU28+ |
Conservation and management needs
List of conservation and management needs
- Measures related to marine habitats
- Other marine-related measures
- Restoring marine habitats
- 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 | 255,226 | Decreasing | Unknown |
| Celtic Seas | ||||
| Kattegat | ||||
| Greater North Sea | ||||
| 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 | 5,012,574 | 6,236 | >255,226 | The area estimate for this habitat has been derived from a synthesis of EUNIS seabed habitat geospatial information for the European Seas but is recognised as being an underestimate. |
| EU28+ | >6,236 | >255,226 | 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).
