Biodiversity & Conservation

Rhodothamniella floridula on sand-scoured lower eulittoral rock



Image Kate Northen - Sand tolerant red algae on lower shore. Image width ca 60 cm (foreground).
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Distribution map

LR.MLR.BF.Rho 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 Uncommon
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Fish and crustaceans, migrating into the intertidal zone to feed as the tide rises, are important predators of rocky shore species. Shore birds also feed on the rocky shores because the invertebrates attracted to seaweed on the strandline are a particularly important food source. Algal patches may provide nursery grounds for various species.


  • Fucus serratus is one of several algal species that might be harvested. Removal of some of the adult canopy will allow the understorey and algal turf to grow faster.
  • Chondrus crispus, a small purplish-red seaweed, is harvested commercially as carragheen to be used in the pharmaceutical and food industries.
  • The harvesting of these species could affect the species distribution and diversity as a whole.

Additional information icon Additional information

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This review can be cited as follows:

Riley, K. 2002. Rhodothamniella floridula on sand-scoured lower eulittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 27/11/2015]. Available from: <>