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Habitat Type: Littoral muddy sand
Habitat Type: Littoral muddy sand
O
Written by Oliver Lewis
Updated over 7 months ago

The following is a short summary of the habitat type and how to create/enhance it to a "good" condition. For an informed position, please refer to official up-to-date EUNIS documentation or the UK Government's Condition Assessment Sheet.

Shores comprising clean sands (coarse, medium or fine-grained) and muddy sands with up to 25% silt and clay fraction. Shells and stones may occasionally be present on the surface. The sand may be duned or rippled as a result of wave action or tidal currents. Littoral sands exhibit varying degrees of drying at low tide depending on the steepness of the shore, the sediment grade and the height on the shore. The more mobile sand shores are relatively impoverished (EUNIS A2.22), with more species-rich communities of amphipods, polychaetes and, on the lower shore, bivalves developing with increasing stability in finer sand habitats (EUNIS A2.23). Muddy sands (EUNIS A2.24), the most stable within this habitat complex, contain the highest proportion of bivalves.

A strandline of talitrid amphipods (EUNIS A2.211) typically develops at the top of the shore where decaying seaweed accumulates. Fully marine sandy shores occur along stretches of open coast, whilst muddy sands are often present in more sheltered lower estuarine conditions and may be subject to some freshwater influence.

Littoral sandy shore environments can change markedly over seasonal cycles, with sediment being eroded during winter storms and accreted during calmer summer months. The particle size structure of the sediment may change from finer to coarser during winter months, as finer sediment gets resuspended in seasonal exposed conditions. This may affect the sediment infauna, with some species only present in summer when sediments are more stable. More sheltered muddy sand shores are likely to be more stable throughout the year, but may have a seasonal cover of green seaweeds during the summer period, particularly in nutrient enriched areas or where there is freshwater input.

This aligns with the description provided by EUNIS A2.2

How to Create / Enhance to a "Good" condition

There are a set of criteria that are used to judge the condition of this habitat. These are listed below.

Indicator

Good (3 points)

Moderate (2 points)

Poor (1 point)

A

Coastal processes

Coastal processes are functioning naturally. No evidence of human physical modifications which are clearly impacting the habitat.

Artificial structures present e.g. groynes, that are impeding the natural movement of sediments or water, affecting up to 25% of the habitat.

Artificial structures present e.g. groynes, that are impeding the natural movement of sediments or water, affecting more than 25% of the habitat.

B

Presence and abundance of invasive non-native species

Not more than one invasive non-native species is ‘Occasional’ on the SACFOR scale or is occupying more than 1% of the habitat. No high-risk species indicative of suboptimal condition present, see Footnote 1 for details.

No invasive non-native species are present above ‘Frequent’ on the SACFOR scale or they occupy between 1-10% of the habitat. No high-risk species indicative of suboptimal condition present, see Footnote 1 for details.

One or more invasive non-native species are present at an ‘Abundant’ level on the SACFOR scale; they occupy more than 10% of the habitat; or a high-risk species indicative of suboptimal condition is present – GB Non-native Species Secretariat should be notified, see Footnote 1 for details.

C

Water Quality

No visual evidence of pollution. There are no nuisance algal growths that are likely to be attributable to nutrient enrichment. Consider seasonality of survey timing2.

Visual evidence of low to moderate levels of pollution. Elevated algal growth with increases in cover that may indicate nutrient enrichment. Consider seasonality of survey timing2.

Visual evidence of high algal growth that is indicative of nutrient enrichment. Signs of eutrophication that would impede bird feeding. Consider seasonality of survey timing2.

D

Non-natural structures and direct human impacts

No evidence of impacts from direct human activities, or they occupy <1% of the habitat area (for example, pontoons, moorings, boats, crab tiles, bait digging or anchoring scars).

Evidence of impacts from direct human activities occupies 1-10% of the habitat area (for example, pontoons, moorings, boats, crab tiles, bait digging or anchoring scars).

Evidence of impacts from direct human activities occupies >10% of the habitat area (for example, pontoons, moorings, boats, crab tiles, bait digging or anchoring scars).

E

Litter (when examining a beach strandline, mean high water line or intertidal rocky shore)

Following the Marine Conservation Society (MCS) beach litter survey method, the number of items of litter does not exceed 0.0036 m−1 min−1 person−1, equivalent to up to 20 items per person per 100 m per hour. See Footnote 3 for details.

Following the MCS beach litter survey method, the number of items of litter does not exceed 0.0078 m−1 min−1 person−1, equivalent to between 21 and 47 items of litter per person per 100 m per hour. See Footnote 3 for details.

Following the MCS beach litter survey method, the number of items of litter exceeds 0.0078 m−1 min−1 person−1, equivalent to more than 47 items of litter per person per 100 m per hour. See Footnote 3 for details.

Condition Assessment Result

TOTAL SCORE 12-15 (75-100%) = GOOD CONDITION

TOTAL SCORE 8-11 (50-75%) = MODERATE CONDITION

TOTAL SCORE 5-7 (0-50%) = POOR CONDITION

Footnotes

Footnote 1 - Abundances estimated using SACFOR scales details available here: JNCC (No date) SACFOR abundance scale used for both littoral and sublittoral taxa from 1990 onwards [online]. Available from: sacfor.pdf (jncc.gov.uk)

Use the non-native species list available here: Microsoft Word - UK_Marine_NIS_priority_list_2020 (nonnativespecies.org)

DEFRA (2022) UK Marine Non-Indigenous Species Priority List (updated 2020) [online]. Available on: Marine Pathways Group » NNSS (nonnativespecies.org)

  • Ficopomatus enigmaticus - Trumpet tube worm

  • Styela clava - Asian tunicate; leathery sea squirt, club tunicate

  • Corella eumyota - Orange-tipped sea squirt

  • Grateloupia turuturu - Devil’s tongue weed, gracie, red menace and red tide

Intertidal mixed sediment A2.4

  • Ficopomatus enigmaticus - Trumpet tube worm Always check for updates of high-risk species.

Footnote 2 - Peak bloom time is July – September.

Footnote 3 - Please use the method as set out in Nelms et al (2017) to identify litter m−1 min−1 person−1, which is summarised below:
Collect litter along a linear transect parallel with the strandline, located between the back of the beach and the strandline. The transect should be 100 m long. Assign gathered items of litter to one of 101 item categories, and further classify them into 12 material groups (plastic, polystyrene, rubber, cloth, metal, medical, sanitary, faeces, paper, wood, glass, pottery or ceramic) using MCS classifications. Following this, record and sum all anthropogenic litter items and remove them from the beach. Litter identification guides may be useful, please see Nelms et al (2017) for more details on the method:

NELMS, S.E. ET AL. (2017) Marine anthropogenic litter on British beaches: A 10-year nationwide assessment using citizen science data. Science of The Total Environment [online], 579. Available from:

The indicator thresholds for litter are based on the methods in Van Loon et al (2020), which is guidance developed within the Common Implementation Strategy for the Marine Strategy Framework Directive (MSFD) by the MSFD Technical Group on Marine Litter.
VAN LOON, W. ET AL. (2020). A European Threshold Value and Assessment Method for Macro Litter on Coastlines. EUR 30347 EN, Publications Office of the European Union, Luxembourg. [online] Available from:

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