Biodiversity & Conservation

Zostera noltii beds in upper to mid shore muddy sand



Image Mark Davies - A bed of Zostera noltii with Hydrobia ulvae visible on the mud surface. Image width ca 40 cm.
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Distribution map

LS.LMp.LSgr.Znol recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland This biotope is sparsely distributed around the UK, with particularly extensive stands in Cromarty Firth, and along the Essex and north Kent coasts.
National importance Scarce

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Mid and upper shore wave-sheltered muddy fine sand or sandy mud with narrow-leafed eelgrass Zostera noltii at an abundance of frequent or above. This is similar to polychaetes and Cerastoderma edule (LMS.Pcer) since it is most frequently found on lower estuary and sheltered coastal muddy sands with a similar infauna. Exactly what determines the distribution of the Zostera noltii is, however, not entirely clear. Zostera noltii is often found in small lagoons and pools, remaining permanently submerged, and on sediment shores where the muddiness of the sediment retains water and stops the roots from drying out. A black layer is usually present below 5 cm sediment depth. The infaunal community is characterized by polychaetes Pygospio elegans and Arenicola marina, mud amphipods Corophium volutator and bivalves Cerastoderma edule, Macoma balthica and Scrobicularia plana. Typically an epifaunal community is found that includes the mud snail Hydrobia ulvae, shore crabs Carcinus maenas and the green alga Ulva sp. This biotope should not be confused with IMS.Zmar which is a Zostera marina bed on the lower shore or shallow sublittoral clean or muddy sand. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

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This review can be cited as follows:

Tyler-Walters, H. & Wilding, C.M. 2008. Zostera noltii beds in upper to mid shore 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: <>