Biodiversity & Conservation

Zostera marina/angustifolia beds in lower shore or infralittoral clean or muddy sand



Image Keith Hiscock - Current swept bed of Zostera marina. Image width ca 2 m in foreground.
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Distribution map

SS.IMS.Sgr.Zmar recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • Berne
  • 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

  • Laomedia angulata
  • Rhodophysema georgii
  • Halothrix lumbricalis
  • Leblondiella densa
  • Myrionema magnusii
  • Cladosiphon zosterae
  • Punctaria crispata
  • Entocladia perforans

Rare of scarce species associated with this biotope

  • Laomedia angulata
  • Halothrix lumbricalis
  • Leblondiella densa
Community Importance Species name Common Name
Key structural Zostera marina Common eelgrass
Important structural Lacuna vincta Banded Chink shell
Important structural Hydrobia ulvae Laver spire shell


Zostera marina/angustifolia stabilizes the sediment and provides a distinct habitat. Zostera marina is the dominant source of organic matter (through grazing and as detritus). Loss of Zostera spp. would result in rapid change in and loss of the associated community. The fungus Labrynthula macrocystis causes wasting disease and may cause long lasting declines in Zostera sp. beds. It does not appear to cause disease in low salinity conditions. However, Zostera marina is often found in fully saline conditions. Epiphytic grazers, such as Hydrobia ulvae, Rissoa spp. and Lacuna vincta remove fouling epiphytic algae that would otherwise smother Zostera spp. Hydrobia ulvae and Lacuna spp. have been shown to reduce the density of epiphytes on Zostera noltii in the Dutch Wadden Sea (Philippart, 1995a) and Zostera marina in Puget Sound (Nelson, 1997) respectively with subsequent enhancement of the productivity of sea grass.

Additional information

Species richness is derived from the number of species recorded in MNCR database for this biotope. Zostera beds, in particular Zostera marina, are species rich habitats. Species diversity is highest in subtidal, fully marine, perennial populations of Zostera marina when compared to intertidal, estuarine or annual beds of Zostera spp. Representative and characteristic species are listed by Davison & Hughes (1998). Species lists for major eelgrass beds are available for the Helford Passage (Sutton & Tompsett, 2000) and Isles of Scilly (Hiscock, S., 1984). Hiscock, S. (1987) listed 67 algae in Zostera marina beds in the Isles of Scilly. Proctor (1999) lists 63 species of fauna in Zostera sp. beds in Torbay. Hiscock, S. (1987) noted that colonial diatoms were the most abundant algae on Zostera marina leaves in the Isles of Scilly. However, it should be noted that species lists are likely to underestimate the total number of species present, especially with respect to microalgae epiphytes, bacteria and meiofauna.

This review can be cited as follows:

Tyler-Walters, H. & Wilding, C.M. 2008. Zostera marina/angustifolia beds in lower shore or infralittoral clean or muddy sand. 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: <>