Biodiversity & Conservation

Laminaria hyperborea with dense foliose red seaweeds on exposed infralittoral rock.

IR.EIR.KFaR.LhypR


EIR.LhypR

Image Anon. - Laminaria hyperborea forest with dense foliose red seaweeds on exposed upper infralittoral rock (EIR.LhypR.Ft). Image width ca 3 m in foreground.
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Distribution map

IR.EIR.KFaR.LhypR recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)


  • EC_Habitats

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

  • Helcion pellucidum
  • Obelia geniculata
  • Membranipora membranacea
  • Palmaria palmata
  • Membranoptera alata
  • Phycodrys rubens
  • Myrionema corunnae
Community Importance Species name Common Name
Key structural Laminaria hyperborea Tangle or cuvie
Key functional Helcion pellucidum Blue-rayed limpet
Key functional Echinus esculentus Edible sea urchin
Important characterizing Delesseria sanguinea Sea beech

Explanation

Laminaria hyperborea provides substratum for numerous species and is the major source of primary production in this community, either directly or in the form of drift (broken off) algae. The biotope would cease to be EIR.LhypR if Laminaria hyperborea was lost. Helcion pellucidum grazes the blades of kelp directly and the laevis form excavates cavities in the holdfasts. These cavities weaken the holdfast making it more susceptible to removal by wave action and storms, and affects the age structure of the kelp population since older, larger plants are most likely to be lost. Sea-urchins have been responsible for removal of large areas of kelp bed in Nova Scotia, Norway and Southern California, resulting in 'urchin barrens'. The presence of this biotope is partly reliant on low or no populations of sea urchins, such as Echinus esculentus. Sea urchins are omnivores and graze drift algae, algal turfs, epifauna and epiphytes on kelp. Their grazing may prevent dominance by any one species, resulting in a more species rich epifauna/flora. Echinus esculentus has been shown to control the lower limit of Laminaria hyperborea in Isle of Man, affect the patchiness and species composition of the understorey algae and remove Laminaria hyperborea sporelings and juveniles. Sporelings did not survive past 2 years of age in areas grazed by urchins (Jones & Kain 1967; Kain 1979). Echinus esculentus is the common sea urchin in the British Isles. The EIR.LhypR biotope is characterized by dense red algae turf, of which Delesseria sanguinea is an important characterizing species. If the red algal turf was lost the biotope may change to EIR.LhypPar or EIR.LhypFa. Although sea urchins are considered keystone the mechanisms that control their populations are poorly understood. In undertaking this assessment of sensitivity, account is taken of knowledge of the biology of all characterizing species in the biotope. However, 'indicative species' are particularly important in undertaking the assessment because they have been subject to detailed research.

Additional information

Little work on the rarity of species in kelp biotopes has been compiled (Birkett et al., 1998b). Kelp beds are diverse species rich habitats and over 1,800 species have been recorded in the UK kelp biotopes (Birkett et al., 1998b). Birkett et al. (1998b) list species recorded in UK biotope complexes by the MNCR (Appendix 5) together with common understorey algae and epiphytes (Appendices 4 & 3 respectively).
Holdfast fauna is a particularly species rich part of the biotope but no species have been suggested as specifically associated with holdfasts and therefore critical to the identity of the biotope.


This review can be cited as follows:

Tyler-Walters, H. 2005. Laminaria hyperborea with dense foliose red seaweeds on exposed infralittoral rock.. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 01/08/2014]. Available from: <http://www.marlin.ac.uk/habitatreproduction.php?habitatid=171&code=1997>