Red List habitat classification > RL - Marine habitats > RLBLS - Black Sea > BLSA1.44 Pontic mediolittoral caves and overhangs

Pontic mediolittoral caves and overhangs

Quick facts

Red List habitat type code BLSA1.44
Threat status
Europe Least Concen
EU Endangered
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


Where caves and overhangs occur on rocky shores, the shaded nature of the habitat diminishes the amount of desiccation suffered by biota during Aeolian periods of low water which allows certain species to proliferate. In addition, the amount of scour, wave surge, sea spray and penetrating light determines the unique community assemblages found in upper, mid- and lower shore caves and overhangs on the lower shore. All around the Black Sea this habitat type occurs in the Sarmatian limestone cliffs in Russia, Ukraine, Romania, Bulgaria and Turkey. It may also occur in volcanic and metamorphic rocks, such as Maslen Nos Cape in Bulgaria. The height of the entrance varies from 50 cm up to 25 m depending on the strength of the waves. The length of the water gallery is between 3 and 50 m and is sometimes followed by dry or semi-dry galleries with sand, gravel and larger stones. Natural light does not reach the inner reaches of the longest caves. The temperature strongly depends on the situation outside the cave, although fluctuations are smaller and no extremely high or low values have been recorded.

Indicators of quality:

Biotic indicators of good quality include the presence of sponge assemblages and the abundance and extent of sponge crusts. Abiotic indictors of good quality include water quality (i.e. low nutrients: N, P) and absence  of rubbish. 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

In the EU 28 the habitat type is assessed as Endangered under Criterion B1 and B2. The EOO is 6,248 km2. The AOO is km2. There is a continuous decline in quality due to rubbish dumping and unsupervised tourism, solely based on expert opinion.
In the EU 28+ the habitat type is assessed as Least Concern under Criterion A1 and B. There has been a decline in extent of <25% in the last 50 years, based on expert opinion. The threatened categories for AOO and EOO are not met for Criterion B
Current total area of the habitat is unknown.
In the historic period (pre-1965) the habitat extent is believed to have remained stable in Turkey and Bulgaria as caves are typically located in steep cliffs in remote areas, which are unsuitable for development. In the recent past (1965 to present day) the habitat extent has remained stable and expert opinion is that this is predicted to remain the case in the future.
In the historic period (pre-1965) the quality of caves and overhangs are believed to have been stable. The Monk Seal (Monachus monachus) regularly used caves for breeding (based on expert opinion).
In the recent past (1965 to present day) the quality is believed to have remained stable in Turkey. Quality declines are believed to have occurred in Bulgaria associated with eutrophication, rubbish dumping and disturbance by tourists (based on expert opinion of the habitat and its likely response to known pressures). For instance, during the period up to the 1990s widespread and severe eutrophication occurred in the Black Sea. This was most notable in the western Black Sea and is likely to have caused a decline in biotic quality of the habitat as some quality indicators (e.g. sponges) are highly sensitive to these conditions.
In the future the habitat quality is expected to remain stable in Turkey because of the remote localities and low development pressure. In Bulgaria and Crimea peninsula the quality will depend on levels of protection, providing pollution control and regulations on rubbish dumping and unsupervised tourism are enforced.
Red List Category Red List Criteria
Endangered B1a,b,c and B2a,b,c.
Red List Category Red List Criteria
Least Concen

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Urbanisation, residential and commercial development
    • Other urbanisation, industrial and similar activities
  • Human intrusions and disturbances
    • Outdoor sports and leisure activities, recreational activities
  • Pollution
    • Nutrient enrichment (N, P, organic matter)
    • Input of contaminants (synthetic substances, non-synthetic substances, radionuclides) - diffuse sources, point sources, acute events
    • Oil spills in the sea
    • Input of litter (solid waste matter)
  • Natural biotic and abiotic processes (without catastrophes)
    • Erosion

Habitat restoration potential

New caves and overhangs, can form over time but only through natural processes. Intervention is unlikely to increase the extent of this habtiat. The habitat will recover naturally from quality degradation. Intervention can also be used to improve the quality of the controlling rubbish dumping and pollution.

Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Decreasing Stable
EU28 EU28+

Conservation and management needs

Some caves and overhangs are found within protected areas which provide protection from development. However, marine littering and unsupervised tourism remain pressures in these areas.
In the future, regulations on rubbish dumping and unsupervised tourism need to be enforced to improve the conservation status of the habitat.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to marine habitats
    • Other marine-related measures
  • Measures related to spatial planning
    • Establish protected areas/sites
  • Measures related to urban areas, industry, energy and transport
    • Urban and industrial waste management


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 Stable

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 6,248 7 Unknown Current total area of the habitat is unknown.
EU28+ 73 Unknown Current total area of the habitat is unknown.
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.
Algae Phyllophora crispa
Mammals Miniopterus schreibersii
Mammals Monachus monachus
Mammals Myotis blythii
Species scientific name English common name Species group
Phyllophora crispa Algae
Miniopterus schreibersii Schreiber's Bat Mammals
Monachus monachus Mediterranean monk seal Mammals
Myotis blythii Lesser mouse-eared bat Mammals

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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