Seagrass beds on Atlantic infralittoral sand (Macaronesian)
Quick facts
Red List habitat type | code NEAA5.53A |
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Threat status | |
Europe | Vulnerable |
EU | Vulnerable |
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 habitat consists of beds of submerged marine angiosperms in the genera Cymodocea, Halophila, Ruppia, Thalassia and Zostera in the southern islands of Macaronesia (it does not occur in the Azores). Seagrass beds are present mainly off the sheltered eastern coasts of the Canary Islands (Spain), on the wide subtidal platforms with sandy substrata and gently sloping coastlines which are sheltered from the Trade Winds. They may occur in patches or form extensive meadows reaching depths of over 30m where light levels are sufficient to support growth. C. nodosa has also been reported in scattered locations along the southern coast of Madeira Island (Portugal). In the Canary Islands, C.nodosa can be found forming unispecific meadows, but also mixed with Halophila decipiens on muddy bottoms or with the green macroalga Caulerpa prolifera on sandy bottoms.
Marine seagrass meadows are very important in providing several ecological services, such as primary production, habitats, nurseries and coastal protection. Primary productivity may vary, depending on many factors such as the density of the meadow, geographic area or hydrologic factors. These ecosystems are one of the most important habitats for several marine organisms, which depend on them in different phases of their life cycle, not only to feed but also to take shelter from predators.
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. Total area covered, density of the intertidal beds and species composition is, for example, used as a Water Framework Directive parameter for assessing ecological status.
The overall quality and continued occurrence of this habitat is dependent on the presence of seagrass species which create the biogenic structural complexity on which the characteristic associated species depend. The density and the maintenance of a viable population of seagrass is therefore a key indicator of habitat quality, together with the visual evidence of presence or absence of physical damage. Shoot density and leaf length have both been examined as potential indicators of quality of this habitat.
Threat status
Synthesis of Red List assessment
Expert opinion is that over the last 50 years the decline in quantity is estimated to have been over 30% and that the decline in quality has been substantial with a severe decline affecting more than 30% of the extent of this habitat. The Red List assessment is therefore that this is a Vulnerable habitat for both the EU 28 and EU 28+.
EU | |
Red List Category | Red List Criteria |
Vulnerable | A1, C/D1 |
Europe | |
Red List Category | Red List Criteria |
Vulnerable | A1, C/D1 |
Confidence in the assessment
Pressures and threats
- Transportation and service corridors
- Shipping lanes, ports, marine constructions
- Biological resource use other than agriculture & forestry
- Marine and Freshwater Aquaculture
- 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...)
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 |
|
Decreasing ![]() |
Decreasing ![]() |
EU28 | EU28+ |
Conservation and management needs
List of conservation and management needs
- Measures related to wetland, freshwater and coastal habitats
- Restoring/Improving water quality
- Restoring/Improving the hydrological regime
- Measures related to marine habitats
- Restoring marine habitats
- Measures related to spatial planning
- Establish protected areas/sites
- Legal protection of habitats and species
- Measures related to hunting, taking and fishing and species management
- Regulation/Management of fishery in marine and brackish systems
- Measures related to urban areas, industry, energy and transport
- Urban and industrial waste management
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) |
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Macaronesia | 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 | 153,446 | 59 | unknown | EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status. |
EU28+ | 59 | unknown | EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status. |
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).