Infaunal communities of Baltic upper circalittoral sand dominated by bivalves
Quick facts
| Red List habitat type | code BAL53 |
|---|---|
| Threat status | |
| Europe | Near Threatened |
| EU | Near Threatened |
| Relation to |
|
| Source | European Red List habitat factsheet |
| European Red List of habitats reports | |
| European Red List of habitats (Excel table) |
Summary
This Baltic Sea benthic habitat occurs in the aphotic zone in high energy exposure areas with at least 90% coverage of sand according to the HELCOM HUB classification. Typically no macrovegetation or epibenthic macrofauna are present and infaunal bivalves make up at least 10% of the biomass.
Seven associated biotopes with different dominant species (at least 50% of the biomass) of macrofauna have been identified. These include the Baltic tellin (Macoma balthica) the ocean quahog (Arctica islandica) and the sand gaper (Mya arenaria).The dominance structure might vary considerably between stations and the substrate contains different proportions coarse or medium sand, but may also contain finer or coarser sediment fractions. The associated biotopes may also have some differences in distribution. For example ‘Baltic aphotic sand dominated by multiple infaunal polychaete species including Ophelia spp.’ (AB.J3L11) is restricted to the Belt Sea (sandbanks) and parts of the ‘submerged belt’ of the Arkona Basin in the western Baltic Sea; the biotope ‘Baltic aphotic sand dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.’ (AB.J3L10) is encountered in the western Baltic Sea, from the Kiel Bight to Isle of Fehmarn, and might occasionally occur from Mecklenburg Bight to the Darss Sill.
Characteristic species
For full habitat description, please download the habitat factsheet.
Threat status
Synthesis of Red List assessment
The presence of this habitat type in the Baltic is well know.n It occurs in all the sub basins but quantitative data on the area covered are not available. There have been declines in both quantity and quality of this habitat particularly for those areas dominated by Arctica islandica.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AB.J3L4 as Least Concern (A1), AB.J3L10 and AB.J3L11 as Near Threatened (A1) and AB.J3L3 as Vulnerable (A1). Biotopes AB.J3L1 and AB.J3L9 were not evaluated. Expert opinion is that there have been significant declines in the extent of some of the associated biotopes and an overall reduction of more than 25%. This habitat has therefore been assessed as Near Threatened for both the EU 28 and EU 28+.
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed AB.J3L4 as Least Concern (A1), AB.J3L10 and AB.J3L11 as Near Threatened (A1) and AB.J3L3 as Vulnerable (A1). Biotopes AB.J3L1 and AB.J3L9 were not evaluated. Expert opinion is that there have been significant declines in the extent of some of the associated biotopes and an overall reduction of more than 25%. This habitat has therefore been assessed as Near Threatened for both the EU 28 and EU 28+.
| EU | |
| Red List Category | Red List Criteria |
| Near Threatened | A1 |
| Europe | |
| Red List Category | Red List Criteria |
| Near Threatened | A1 |
Confidence in the assessment
low
Red List of habitat categories and criteria descriptions
Pressures and threats
- Mining, extraction of materials and energy production
- Mining and quarrying
- Sand and gravel extraction
- Exploration and extraction of oil or gas
- 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)
- Input of contaminants (synthetic substances, non-synthetic substances, radionuclides) - diffuse sources, point sources, acute events
Habitat restoration potential
For the biotope with the highest threat category (VU, A1), AB.J3L3 ‘Baltic aphotic sand dominated by ocean quahog (Arctica islandica)', the habitat forming species is the most long-lived species in the world and has a long generation time. It is likely to be difficult to undertake a re-establishment programme for this species as this would require a commitment of more than 50 years. No information exist on the capacity for recovery of the other associated biotopes.
Trends in extent |
|
Average current trend in quantity |
|
Decreasing  |
Decreasing |
| EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
| Decreasing |
Decreasing |
| EU28 | EU28+ |
Conservation and management needs
All actions that reduce the level of eutrophication in the Baltic Sea will benefit this habitat. These include measures to reduce the diffuse run off of nutrients from agriculture and tackling point source pollution by installation of waste water treatment plants. The aphotic sandy substrates may increasingly be used for mineral extraction. Restricting or prohibiting sand extraction from some areas will support the persistence of this habitat.
List of conservation and management needs
- Measures related to wetland, freshwater and coastal habitats
- Restoring/Improving water quality
- Measures related to spatial planning
- Establish protected areas/sites
- Legal protection of habitats and species
- Measures related to hunting, taking and fishing and species management
- Regulation/Management of fishery in marine and brackish systems
- Measures related to special resouce use
- Regulating/Managing exploitation of natural resources on sea
Distribution
For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively
reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.
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) |
|---|---|---|---|---|
| Baltic Proper | Present | Unknown | Decreasing | Decreasing |
| Belt Sea | ||||
| Gulf of Bothnia | ||||
| Gulf of Finland | ||||
| Gulf of Riga | ||||
| The Sound |
Extent of Occurrence, Area of Occupancy and habitat area
| Extent of Occurrence (EOO) (Km2) | Area of Occupancy (AOO) | Current estimated Total Area | Comment | |
|---|---|---|---|---|
| EU28 | >50,000 | Unknown | Unknown | This habitat is present in all the Baltic sub-basins. |
| EU28+ | Unknown | Unknown | This habitat is present in all the Baltic sub-basins |
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
Characteristic species
Not available
Legal status
Relation to other habitat types mentioned in legal instruments
Vegetation types
Relation to vegetation types (syntaxa)
Not availableOther classifications
Not available
