Red List habitat classification > RL - Marine habitats > RLBLS - Black Sea > BLSA5.53 Seagrass and rhizomatous algal meadows in Pontic freshwater-influenced sheltered infralittoral muddy sands and sandy muds

Seagrass and rhizomatous algal meadows in Pontic freshwater-influenced sheltered infralittoral muddy sands and sandy muds

Quick facts

Red List habitat type code BLSA5.53
Threat status
Europe Near Threatened
EU Least Concern
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This habitat occurs in sheltered shallow (0.5-2 m) coastal waters (embayments, inlets, bights, harbours, estuaries), more or less influenced by freshwater (salinity 0.5-10 psu), where sedimentary stability leads to mudding of the sand. Mixed or monospecific meadows are formed by Zostera noltei, Ruppia maritima, R. cirrhosa, Chara spp., Stuckenia pectinata (formerly known as Potamogeton pectinatus), Najas minor and Ranunculus baudotii. Algae commonly found include species of Cladophora and Ulva which are tolerant of very low salinities.

Indicators of quality: 

Both biotic and abiotic indicators have been used to describe marine habitat quality. These include the presence of particular species, water quality parameters, levels of exposure to a particular exposure as well as more integrated indices which describe habitat function and structure, such as trophic index, or successful stages of development in habitats that have a natural cycle of change over time. There are no known commonly agreed indicators of quality for this habitat, although particular parameters may be set in certain situations, e.g. protected features with Natura 2000 sites, where reference values may have been determined and applied on a location-specific basis. Some potential indicators of quality for this specific habitat are thepresence of species (i.e. Zanichellia and Ruppia); species density; species composition; the ratio of higher plants to seagrasses; and biomass. There is insufficient information to set indicator thresholds required for monitoring purposes. 

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

Threat status

Synthesis of Red List assessment

There has been a slight decline in extent in the last 50 years in the EU 28, based on expert opinion. Therefore the habitat is assessed as Least Concern under Criterion A1.
In the EU 28+ the habitat type is assessed as Near Threatened under Criterion A1 as there has been a decline in extent of 25-30% in the last 50 years. This based on a combination of quantitative and qualitative data and expert opinion. Data is from sites in Crimea and Ukraine only and has been extrapolated for the rest of the Black Sea.
Red List Category Red List Criteria
Least Concern -
Red List Category Red List Criteria
Near Threatened A1

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Nutrient enrichment (N, P, organic matter)
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Removal of sediments (mud...)
    • Extraction of sea-floor and subsoil minerals (e.g. sand, gravel, rock, oil, gas)
    • Modification of hydrographic functioning, general
    • Siltation rate changes, dumping, depositing of dredged deposits

Habitat restoration potential

The habitat can recover naturally if the water quality is improved and the hydrological regime is stable. Recovery through intervention is not appropriate for this habitat type.

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

The habitat is a characteristic feature of several habitat types listed in Annex 1 of the Habitats Directive like 1130 Estuaries. As a result it is included in Special Areas of Conservation (SACs). These areas are also included within Specially Protected Areas (SPAs) under the Birds Directive.
In EU states water quality and management are managed by the Water Framework Directive (WFD). Future management should include the designation of additional protected areas in non EU member states and improvement of water quality management and extraction regulations outside EU member states

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
    • Restoring/Improving the hydrological regime
    • Managing water abstraction
  • Measures related to spatial planning
    • Establish protected areas/sites
    • Legal protection of habitats and species


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)
Black Sea Present Unknown Decreasing Decreasing

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 21,555 18 Unknown Current total area of the habitat is unknown. Localities are known but not studied in detail. Total area estimates cannot be calculated.
EU28+ 65 Unknown Current total area of the habitat is unknown. Localities are known but not studied in detail. Total area estimates cannot be calculated.
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

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Phone: +45 3336 7100