Red List habitat classification > RL - Marine habitats > RLBAL - Baltic > BAL59 Sparse epibenthic community of Baltic upper circalittoral muddy sediment

Sparse epibenthic community of Baltic upper circalittoral muddy sediment

Quick facts

Red List habitat type code BAL59
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 Baltic Sea benthic habitat occurs in the aphotic zone where there is at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic fauna is present but covers less than 10% of the seabed. One associated biotope has been identified: ‘Baltic aphotic muddy sediment dominated by seapens’ (AB.H2T1). This is characterized by conspicuous populations of seapens that usually live scattered over the sea floor but usually cover less than 10% of the muddy surface. It occurs typically from 15 to 200 meters depth in low to moderate energy exposure classes in the highest salinity regions of the Baltic (up to 23 psu in The Sound). These deep water communities are crucially important to the function of the ecosystem. They provide food and shelter for many other species, including commercially important fish.

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 suggested quality parameters including the presence of seapens which are both characterstic of this habitat and vulnerable to the most significant pressures. 

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

Threat status

Synthesis of Red List assessment

This habitat occurs in a spatially limited area of the southern Baltic Sea. It has been heavily disturbed by intensive trawling with more than half the area it occupies considered to have been destroyed in the last 50 years. A contining decline in spatial extent, abiotic and biotic quality is considered likely. Furthermore, because the places where it occurs are not widely separated (all in a small area of The Sound) it can also be considered to be present in very few locations. This means that a single threat (e.g. eutrophication or intensive trawling) may affect all the places where it occurs. For this reason it is also capable of becoming critically endangered or collapsed within a very short time period.
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 this habitat as Endangered on the basis of a decline in quantity over the last 50 years. Its restricted distribution, clustered location, and likely continuing decline in quantity and quality means that for the current assessment expert opinion is that this habitat should be considered to be Endangered for the EU 28. It is not present and has therefore not been assessed for EU 28+.
EU
Red List Category Red List Criteria
Endangered A1,B1,B2,B3
Europe
Red List Category Red List Criteria
Endangered A1,B1,B2,B3

Confidence in the assessment

medium
Red List of habitat categories and criteria descriptions

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)
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Siltation rate changes, dumping, depositing of dredged deposits
    • Dumping, depositing of dredged deposits
    • Other siltation rate changes

Habitat restoration potential

Time between damaging activity, the type of damage activity and the predominant species influences recovery. Recovery times following dredging of similar habitats in the North Sea were significantly shorter for short-lived species (<1–3 years), free-living and tube-dwelling species and for scavenging or opportunistic species, than for medium live species (3–10 years), burrow-dwelling species and suspension feeders. In trawled areas, recovery times were significantly shorter for free-living species, species covered by an exoskeleton or a hard tunic and species that produce pelagic or benthic eggs than for epiphytic/zoic species, species that grow attached to the substratum and have an erect or stalked body form and species that reproduce asexually. Differences in the recoverability of different species groups following fishing may result in changes in community composition and ecosystem functioning over the long term. Recovery times following oxygen depletion and pollution has been investigated in several studies of the Gullmarsfjord, Sweden showing recovery times of between 2-8 years.

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

Restrictions on bottom trawling in areas where this habitat occurs (The Sound trenches) is the most significant action that would benefit this habitat. This may be introduced both within and outside the boundaries of Marine Protected Areas and would prevent the loss of this habitat from the Baltic. Improvements in water quality (N, P and organic matter levels) reducing the risk of anoxic events in the bottom waters of the Sound, and preventing dreding and disposal of dredge spoils in areas where this habitat occurs are further valuable conservation management measures.

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
  • Measures related to special resouce use
    • Other resource use measures

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)
Belt Sea Present max Decreasing Decreasing
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 2,800 19 max 1900 Based on presence in 100 x 100km grid squares therefore maximum potential EOO and AOO
EU28+ 19 max 1900 Based on presence in 100 x 100km grid squares therefore maximum potential 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 Pennatula phosphorea
Invertebrates Virgularia mirabilis
Species scientific name English common name Species group
Pennatula phosphorea Invertebrates
Virgularia mirabilis Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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