Red List habitat classification > RL - Marine habitats > RLBAL - Baltic > BAL41 Sparse or no macrofaunal communities on Baltic infralittoral muddy sediment

Sparse or no macrofaunal communities on Baltic infralittoral muddy sediment

Quick facts

Red List habitat type code BAL41
Threat status
Europe Least Concern
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 is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is muddy sediment according to the HELCOM HUB classification. It occurs in areas where there is low to medium exposure to wave action. Macrovegetation, epifauna and infauna are generally sparse or absent however the one associated biotope described has a large representation (more than 50% of biomass) of meiofauna. This is ‘Baltic photic muddy sediment dominated by meiofauna (Oligochaeta, Ostracoda, Nematoda)’ (AA.H4U1).

The benthic meiofauna in the Baltic Sea is a diverse group of small animals including Ostracoda, Nematoda, Oligochaeta, Rotifera, Turbellaria and Copepoda living on and in the sediments. In the north-western Baltic Sea Proper, Nematoda are the most abundant group of benthic meiofauna, making up between 67–91% of the species observed in the sediment. Only nematodes are found to be common below 2 cm depth in the sediment. Meiofauna can be split into surface feeders and subsurface feeders. Sedimentation of organic matter may have an effect on the meiofaunal community, as the increased rate of sedimentation can increase the abundance of surface feeding species.

Indicators of quality:

Quality indicators have not been described for this habitat. Generally the ecology of meiofaunal communities is less well understood than that of benthic macrofauna communities. Fewer studies have been carried out and in many studies meiofauna is only stated to be present in a certain abundance. Studies looking into the environmental requirements and species interactions are rare. It is also quite rare that meiofauna is taxonomically identified to species level which is the rule in macrofauna studies. 


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

Threat status

Synthesis of Red List assessment

This habitat is considered to have expanded its extent over the last 50 years due to nutrient enrichment, however, this has not been quantified. 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 Least Concern (A1) due to the increase in extent in the last 50 years with nutrient enrichment. The current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.
Red List Category Red List Criteria
Least Concern
Red List Category Red List Criteria
Least Concern

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • No threats or pressures
    • No threats or pressures

Habitat restoration potential


Trends in extent

Average current trend in quantity

Increasing Increasing
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

No conservation or management measures have been identified specifically for this habitat.

List of conservation and management needs

  • No measures
    • No measures needed for the conservation of the habitat/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)
Baltic Proper Present unknown Unknown Increasing
Gulf of Bothnia
Gulf of Finland
Gulf of Riga

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 unknown unknown unknown There is insufficient quantitative data to make an accurate estimate of EOO and AOO.
EU28+ unknown unknown There is insufficient quantitative data to make an accurate estimate 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

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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