Biodiversity & Conservation

Faunal and algal crusts, Echinus esculentus, sparse Alcyonium digitatum and grazing-tolerant fauna on moderately exposed circalittoral rock

CR.MCR.EcCr.FaAlCr.Pom

MCR.FaAlC

Image David Connor - Faunal and algal crusts, Echinus esculentus, sparse Alcyonium digitatum, Abietinaria abietina and other grazing-tolerant fauna on moderately exposed circalittoral rock. Image width ca 1m.
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Distribution map

CR.MCR.EcCr.FaAlCr.Pom recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Marine natural heritage importance

Listed under EC Habitats Directive
National importance Not available
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Epifaunal habitats are dominated by suspension feeding invertebrates and probably have an important role in marine food webs by transferring primary productivity from the photic zone and the plankton or shallow coastal water macroalgae to the benthos, so called termed 'benthic-pelagic' coupling (Gili & Hughes, 1995). For example, the hydroid species of Obelia were shown to regulate the production of local copepod populations, whereas the hydroid Campanularia everta was shown to transfer 1528 mg C /m²/yr of energy to its own biomass (Gili & Hughes, 1995). But the epifaunal population in this biotope is sparse in comparison to other epifaunal communities so its importance may be limited.

Exploitation

Collecting of Echinus esculentus for the curio trade was studied by Nichols (1984). He concluded that the majority of divers collected only large specimens that are seen quickly and often missed individuals covered by seaweed or under rocks, especially if small. As a result, a significant proportion of the population remains. He suggested that exploited populations should not be allowed to fall below 0.2 individuals per square metre.

Additional information icon Additional information

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This review can be cited as follows:

Tyler-Walters, H. 2002. Faunal and algal crusts, Echinus esculentus, sparse Alcyonium digitatum and grazing-tolerant fauna on moderately exposed circalittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 19/06/2013]. Available from: <http://www.marlin.ac.uk/habitatimportance.php?habitatid=337&code=2004>