Biodiversity & Conservation

Fucus ceranoides on reduced salinity eulittoral rock



Image Rohan Holt - Fucus ceranoides near freshwater stream. Image width ca 40 cm.
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Distribution map

LR.SLR.FX.FcerX recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

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

  • Fucus ceranoides
Community Importance Species name Common Name
Key structural Fucus ceranoides Horned wrack
Key functional Littorina littorea Common periwinkle
Important characterizing Ulva intestinalis Gut weed
Important other Semibalanus balanoides An acorn barnacle


The fucoid, Fucus ceranoides is dominant in the biotope and is considered to be the 'key structuring' species owing to the distinct habitat and shelter that its fronds provide to mobile and sessile epifauna and epiphytic algae that are tolerant of reduced salinity. It also represents other fucoid algae. Littorina littorea is a 'key functional' species as its grazing activity can affect seaweed diversity. Ulva is an 'important characterizing' species that is opportunistic and can also tolerate reduced salinity conditions. For instance, in the SLR.FcerX biotope also represented by this review, Ulva colonizes areas with a freshwater influence. Semibalanus balanoides is an 'important other' epilithic species whose presence may affect the sensitivity of the biotope. It also represents other barnacle species that might occur in the biotope, such as Elminius modestus and Balanus improvisusalthough account is taken of the lower salinity tolerance of theses species.

Additional information

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This review can be cited as follows:

Budd, G.C. 2007. Fucus ceranoides on reduced salinity eulittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>