Stable aggregations of unattached perennial vegetation on Baltic infralittoral muddy sediment
Quick facts
Red List habitat type | code BAL34 |
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Threat status | |
Europe | Least Concern |
EU | Least Concern |
Relation to |
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Source | European Red List habitat factsheet |
European Red List of habitats reports | |
European Red List of habitats (Excel table) |
Summary
This benthic Baltic Sea habitat occurs in the photic zone with at least 90% coverage of muddy sediment according to the HELCOM HUB classification. Stable aggregations of unattached perennial vegetation cover at least 10%, while perennial attached erect groups or Mytilus cover less than 10% of the bottom. The habitat is encountered in areas with salinity below 10 or 5 psu (depending on the area) and can be found in most of the Baltic Sea area, where the seabed is level over wide areas within the photic zone. The algae provide shelter and surface for attachment of invertebrates, however, if abundances of the unattached form are very high the sediment below may become deoxygenated and the associated infauna may die. The unattached forms of associated algae can coexist with attached forms and the characteristic rooted vegetation of bays, estuaries and lagoons.
Five associated biotopes have been described some of which have a more restricted distribution. These are variously dominated by unattached Fucus spp., Furcellaria lumbricalis, or by the dwarf form of Fucus species which coexists with attached F. vesiculosus, unattached Furcellaria lumbricalis, higher plants like Ruppia spp., Zannichellia palustris, Stuckenia pectinatus (formerly known as Potamogeton pectinatus), Zostera spp. and several charophytes. There are also biotopes dominated by stable aggregations of unattached rigid hornwort (Ceratophyllun demersum) and the unattached lake ball (Aegagropila linnaei).
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. For this habitat the density of unattached Fucus spp. (typical and dwarf forms), lower limit of Furcellaria belt, amount of epiphytic algae, and density of Furcellaria are potential indicators of quality.
Threat status
Synthesis of Red List assessment
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 the the unattached dwarf form of Fucus (AA.H1Q2) as Endangered (A1). The other biotopes (AA.H1Q1, AA.JHQ3, AA.H1Q4 and AA.H1Q5) were assessed as Least Concern (A1). The dwarf form is believed to constitute perhaps 1% of this habitat, consequently the overall assessment for this habitat type is Least Concern for both the EU 28 and EU 28+ because although there have been declines, taken together these are not believed to have exceeded 25% over the last 50 years.
EU | |
Red List Category | Red List Criteria |
Least Concern | - |
Europe | |
Red List Category | Red List Criteria |
Least Concern | - |
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)
- Input of contaminants (synthetic substances, non-synthetic substances, radionuclides) - diffuse sources, point sources, acute events
- Climate change
- Changes in abiotic conditions
- Temperature changes (e.g. rise of temperature & extremes)
- Wave exposure changes
- Sea-level changes
- Habitat shifting and alteration
Habitat restoration potential
Trends in extent |
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Average current trend in quantity |
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Decreasing ![]() |
Decreasing ![]() |
EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
Unknown ![]() |
Unknown ![]() |
EU28 | EU28+ |
Conservation and management needs
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
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) |
---|---|---|---|---|
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 | >50000 | 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 |
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
Characteristic species
Species scientific name | English common name | Species group |
---|---|---|
Fucus vesiculosus | Algae | |
Furcellaria lumbricalis | Algae | |
Ceratophyllum demersum | Flowering Plants | |
Potamogeton pectinatus | Flowering Plants | |
Zannichellia palustris | Flowering Plants |