Biodiversity & Conservation

Ascophyllum nodosum on very sheltered mid eulittoral rock.


<i>%Ascophyllum nodosum%</i> on very sheltered mid eulittoral rock.
Distribution map

LR.LLR.F.Asc recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

For a list of 2004 characterising species please see the JNCC website.

Species indicative of sensitivity

To assess the sensitivity of the biotope, the sensitivity of component species is reviewed. Those species that are considered to be particularly indicative of the sensitivity of the biotope, and for which research has been undertaken in detail are shown below (see selection criteria). The biology of other component species of the biotope is also taken into account wherever information is known to the researcher.

Species found especially in this biotope

  • Ascophyllum nodosum
Community Importance Species name Common Name
Key structural Ascophyllum nodosum Egg wrack
Key functional Patella vulgata Common limpet
Important functional Hyale prevostii An amphipod
Important functional Semibalanus balanoides An acorn barnacle


The seaweed Ascophyllum nodosum is the key structural species for the biotope. Barnacles, represented here by Semibalanus balanoides, are important space occupiers in rocky shore biotopes. There are several grazers in the biotope. Patella vulgata is an important grazer of microalgae on the surface of rocks and can contribute to the regulation of algal patches. The amphipod Hyale prevostii has been included because it is a characteristic species of fucoid dominated rocky shores, an important mesograzer and because amphipods are generally regarded as sensitive species.

Additional information

This review can be cited as follows:

Hill, J.M. 2001. Ascophyllum nodosum on very sheltered mid eulittoral rock.. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 01/12/2015]. Available from: <>