Red List habitat classification > RL - Marine habitats > RLBAL - Baltic > BAL49 Epibenthic communities in Baltic upper circalittoral mixed sediment

Epibenthic communities in Baltic upper circalittoral mixed sediment

Quick facts

Red List habitat type code BAL49
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 is a Baltic Sea benthic habitat in the aphotic zone. The substrate is a mix of  soft or crystalline rock, boulders or stones mixed with mobile substrates such as sand or coarse substrate as well as muddy sands as defined in the HELCOM HUB classification. It typically occurs in depths from 20-150m and seven associated biotopes have been described, some of which are more common in particular depth zones. The biotopes are variously characterised by epibenthic bivalves, chordates, cnidarians (soft corals and sea anemones), bryozoans, crustaceans, sponges and a mixed epibenthic macrocommunity. Some occur in all the sub-basins of the Baltic Sea whereas as others, such as aphotic mixed substrates characterised by epibenthic sponges, are only reported from the Belt Sea and the Gulf of Bothnia. Depending on the dominant species the biotope may either be encrusting or form a layer of living material extending 20cm about the substrate. 

 

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. Diversity, abundance and biomass of fauna are potential indicators of quality.

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

This habitat is known to occur in all the Baltic Sea sub-basins but quantiative data on the area covered is not available. There are considered to have been significant declines (up to 30%) in the extent of many of the associated biotopes and predicted future declines. Some decline in quality (up to an estimated 10%) has also been reported for some of the associated biotopes but the overall trend is uncertain.
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 four of the associated biotopes as NT(A1), and four as LC(A1). One further biotope was not evaluated. On the basis of these assessments and expert opinion, this habitat is assessed as Near Threatened, since there has been an estimated 10-30% decline in quantity over the last 50 years.
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

The associated biotopes dominated by bryozoans have the potential to fairly quickly recolonise destroyed areas after the pressure/threat has been removed and the environmental conditions are restored. The recovery potential is unknown for the other associated biotopes. The overall capacity for recovery is therefore unknown.

Trends in extent

Average current trend in quantity

Decreasing Decreasing
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

All actions which aim to reduce physical disturbance of aphotic habitats on mixed hard and soft substrates in the Baltic Sea would benefit this habitat. In addition, appointing protected areas where the habitat is known to occur and restricting bottom trawling, offshore construction work and exploitation of sand and gravel in these areas would constitute an effective conservation measure. Further mapping activities should be carried out to better delineate the area of occurrence.

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
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in marine and brackish systems

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 Unknown 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 however there is insufficient information for accurate calculation of EOO and AOO.
EU28+ Unknown Unknown This habitat is present in all the Baltic sub-basins however there is insufficient information for accurate calculation of EOO and AOO.
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).

Characteristic species

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Invertebrates Ascidia mentula
Invertebrates Ascidia obliqua
Invertebrates Ascidia virginea
Invertebrates Balanus crenatus
Invertebrates Ciona intestinalis
Invertebrates Dendrodoa grossularia
Invertebrates Electra crustulenta
Invertebrates Eucratea loricata
Invertebrates Flustra foliacea
Invertebrates Gonactinia prolifera
Invertebrates Haliclona oculata
Invertebrates Metridium senile
Invertebrates Modiolus modiolus
Invertebrates Sagartia elegans
Invertebrates Semibalanus balanoides
Invertebrates Stomphia coccinea
Invertebrates Urticina felina
Species scientific name English common name Species group
Ascidia mentula Invertebrates
Ascidia obliqua Invertebrates
Ascidia virginea Invertebrates
Balanus crenatus Invertebrates
Ciona intestinalis Invertebrates
Dendrodoa grossularia Invertebrates
Electra crustulenta Invertebrates
Eucratea loricata Invertebrates
Flustra foliacea Invertebrates
Gonactinia prolifera Invertebrates
Haliclona oculata Invertebrates
Metridium senile Invertebrates
Modiolus modiolus Invertebrates
Sagartia elegans Invertebrates
Semibalanus balanoides Invertebrates
Stomphia coccinea Invertebrates
Urticina felina Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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