Biodiversity & Conservation

Seaweeds in sediment (sand or gravel)-floored eulittoral rockpools

LR.FLR.Rkp.SwSed


LR.SwSed

Image Tom Mercer - Seaweeds in sediment (sand or gravel)-floored eulittoral rockpools. Image width ca 1 m.
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Distribution map

LR.FLR.Rkp.SwSed recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)



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.

Community Importance Species name Common Name
Important characterizing Furcellaria lumbricalis A red seaweed
Important characterizing Ahnfeltia plicata A red seaweed
Important characterizing Polyides rotundus A red seaweed
Important characterizing Rhodothamniella floridula A red seaweed
Important functional Littorina littorea Common periwinkle
Important functional Amphipoda Amphipods

Explanation

This biotope describes a spectrum of rockpools from deep, macroalgal dominated pools to shallow sediment filled pools with sparse sediment tolerant red algae. Therefore, while fucoids, kelps, and green algae may be characterizing species, their abundance and/or presence is likely to vary between pools, and their loss would not herald a loss of an identifiable biotope, although species diversity would be greatly reduced. The most characteristic feature of this rockpool biotope is the presence of sediment, and hence sediment tolerant red algae. Therefore, the red algae Furcellaria lumbricalis, Polyides rotundus, Ahnfeltia plicata and Rhodothamniella floridula have been suggested as important characterizing, as examples of sediment tolerant species. However, it should be noted that not all of the above species occur in all records of the biotope, and hence for sensitivity assessment, sediment tolerant algae will be treated as a functional group rather than individually. Littorina littorea and amphipods are included as important functional species as grazing pressure affects the macroalgal community.

Additional information

The MNCR database lists 449 species in 58 records of this biotope (JNCC, 1999), although not all species occur in all records of the biotope. The seagrass Zostera sp. was recorded from this biotope (see description) and, although no species was given, both Zostera species are nationally scarce.


This review can be cited as follows:

Tyler-Walters, H. 2005. Seaweeds in sediment (sand or gravel)-floored eulittoral rockpools. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 19/12/2014]. Available from: <http://www.marlin.ac.uk/habitatreproduction.php?habitatid=326&code=2004>