Glycera lapidum in impoverished infralittoral mobile gravel and sand

Summary

UK and Ireland classification

Description

In infralittoral mixed slightly gravelly sands on exposed open coasts impoverished communities characterized by the polychaete Glycera lapidum (agg.) may be found. Glycera lapidum is a species complex and as such some variability in identification may be found in the literature. It is also quite widespread, may occur in a variety of coarser sediments and is often present in other SCS biotopes. However, it is rarely considered a characteristic species and where this is the case it is normally due to the exclusion of other species. Consequently, it is considered that habitats containing this biotope may be subject to continual or periodic sediment disturbance from wave action, which prevents the establishment of a more stable community. Other taxa include spionid polychaetes such as Spio martinensis and Spiophanes bombyx, Nephtys spp. and in some areas the bivalve Spisula elliptica. It is possible that SS.SCS.ICS.Glap is not a true biotope, rather an impoverished, transitional community, which in more settled conditions develops into other more stable communities (Information taken from Connor et al., 2004).

Depth range

5-10 m, 10-20 m

Additional information

-

Listed By

Sensitivity reviewHow is sensitivity assessed?

Sensitivity characteristics of the habitat and relevant characteristic species

The biotope description and characterizing species are taken from JNCC (2015). SS.SCS.ICS.Glap is an infralittoral biotope occurring on mixed slightly gravelly sands on exposed open coasts (JNCC, 2015). The impoverished communities that characterize the biotope are dominated by the polychaete Glycera lapidum (agg.), which rarely is considered a characteristic species (Connor et al., 2004). This is likely to be the case in this biotope, where exclusion of other species occurs as a result of continued or periodic sediment disturbance from wave action, preventing the establishment of a more stable community. Other taxa include spionid polychaetes such as Spio martinensis and Spiophanes bombyx, Nephtys spp. and in some areas the bivalve Spisula elliptica. These species, together with Glycera lapidum are considered as important characterizing species and are therefore the focus of this sensitivity assesment.

Resilience and recovery rates of habitat

Glycera spp. are long-lived. Glycera are monotelic having a single breeding period towards the end of their life but may recover through migration and may persist in disturbed sediments due to their ability to burrow (Klawe & Dickie, 1957). Glycera spp. have a high potential rate of recolonization of sediments, but the relatively slow growth-rate and long lifespan suggest that recovery of biomass following initial recolonization by post-larvae is likely to take several years (MES, 2010). Following dredging of subtidal sands in summer and autumn to provide material for beach nourishment in the Bay of Blanes, (north west Mediterranean Sea, Spain) recovery was tracked by Sardá et al. (2000). Glycera spp. had not recovered within two years (Sardá et al., 2000).

A number of studies have tracked recovery of sand and coarse sand communities following disturbance from fisheries (Gilkinson et al., 2005) and aggregate extraction (Boyd et al., 2005). The studies confirm the general trend that, following severe disturbance, habitats are recolonized rapidly by opportunistic species (Pearson & Rosenberg, 1978). Experimental deployment of hydraulic clam dredges on a sandy seabed on Banquereau, on the Scotian Shelf, eastern Canada, showed that within 2 years of the impact, polychaetes and amphipods had increased in abundance after 1 year (Gilklinson et al., 2005). Two years after dredging, abundances of opportunistic species were generally elevated relative to pre-dredging levels while communities had become numerically dominated (50-70%) by Spiophanes bombyx (Gilkinson et al., 2005). Van Dalfsen et al. (2000) found that polychaetes recolonized a dredged area within 5-10 months (reference from Boyd et al., 2005), with biomass recovery predicted within 2-4 years. The polychaete and amphipods are therefore likely to recover more rapidly than the characterizing bivalves and the biotope classification may revert, during recovery, to a polychaete dominated biotope.

Sardá et al. (1999) tracked annual cycles within a Spisula community in Bay of Blanes (north-west Mediterranean Sea, Spain) for 4 years. Macroinfaunal abundance peaked in spring, decreased sharply throughout the summer, with low density in autumn and winter.  The observed trends were related to a number of species, including species that characterize this biotope such as Glycera spp.. The Spisula subtruncata populations were dominated by juveniles, with high abundances in spring followed by declines in summer, with very few survivors 3 months after recruitment. 

Nephtys cirrosa is a relatively long-lived polychaete with a lifespan of six to possibly as much as nine years. It matures at one year and the females release over 10,000 (and up to 80,000 depending on species) eggs of 0.11-0.12mm from April through to March. These are fertilized externally & develop into an early lecithotrophic larva and a later planktotrophic larva which spends as much as 12 months in the water column before settling from July-September. The genus has a relatively high reproductive capacity and widespread dispersion during the lengthy larval phase. It is likely to have a high recoverability following disturbance (MES, 2010).

Where impacts also alter the sedimentary habitat, recovery of the biotope will also depend on recovery of the habitat to the former condition to support the characteristic biological assemblage. Recovery of sediments will be site-specific and will be influenced by currents, wave action and sediment availability (Desprez, 2000). Except in areas of mobile sands, the process tends to be slow (Kenny & Rees, 1996; Desprez, 2000 and references therein). Boyd et al. (2005) found that in a site subject to long-term extraction (25 years), extraction scars were still visible after six years and sediment characteristics were still altered in comparison with reference areas, with ongoing effects on the biota.

Resilience assessment. The species that are present in the biotope can be broadly characterized as either opportunist species that rapidly colonize disturbed habitats and increase in abundance, or species that are larger and longer-lived and that may be more abundant in an established, mature assemblage. The opportunistic species are likely to recolonize disturbed areas first, although the actual pattern will depend on recovery of the habitat, season of occurrence and other factors. The recovery of bivalves that recruit episodically and the establishment of a representative age-structured population for larger, longer-lived organisms may require longer than two years. In an area that had been subjected to intensive aggregate extraction for 30 years, abundances of juvenile and adults Nephtys cirrosa had greatly increased three years after extraction had stopped (Mouleaert & Hostens, 2007). An area of sand and gravel subject to chronic working for 25 years had not recovered after 6 years when compared to nearby reference sites unimpacted by operations (Boyd et al., 2005). Where resistance is ‘None’ and an element of habitat recovery is required, resilience is assessed as ‘Medium’ (2-10 years), based on evidence from aggregate recovery studies in similar habitats including Boyd et al. (2005). Where resistance of the characterizing species is ‘Low’ or ‘Medium’ and the habitat has not been altered, resilience is assessed as ‘High’ as, due to the number of characterizing species and variability in recruitment patterns, it is likely that the biotope would be considered representative and hence recovered after two years although some parameters such as species richness, abundance and biotopes may be altered. Recovery of the seabed from severe physical disturbances that alter sediment character may also take up to 10 years or longer (Le Bot et al., 2010), although extraction of gravel may result in more permanent changes and this will delay recovery.

NB: The resilience and the ability to recover from human induced pressures is a combination of the environmental conditions of the site, the frequency (repeated disturbances versus a one-off event) and the intensity of the disturbance. Recovery of impacted populations will always be mediated by stochastic events and processes acting over different scales including, but not limited to, local habitat conditions, further impacts and processes such as larval-supply and recruitment between populations. Full recovery is defined as the return to the state of the habitat that existed prior to impact. This does not necessarily mean that every component species has returned to its prior condition, abundance or extent but that the relevant functional components are present and the habitat is structurally and functionally recognizable as the initial habitat of interest. It should be noted that the recovery rates are only indicative of the recovery potential. 

Hydrological Pressures

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ResistanceResilienceSensitivity
Temperature increase (local) [Show more]

Temperature increase (local)

Benchmark. A 5°C increase in temperature for one month, or 2°C for one year. Further detail

Evidence

No direct evidence was found to support assessment of this pressure. Very few laboratory studies have been carried out and the sensitivity assessment is based on studies monitoring settlement and recruitment and records of species distribution. 

Kröncke et al. (1998) examined long-term changes in the macrofauna in the subtidal zone off Norderney, one of the East Frisian barrier islands. The analysis suggested that macrofauna were severely affected by cold winters whereas storms and hot summers have no impact on the benthos. A long-term increase in temperature might cause a shift in species composition. Long?term analysis of the North Sea pelagic system has identified yearly variations in larval abundance of Echinodermata, Arthropoda, and Mollusca larvae that correlate with sea surface temperatures. Larvae of benthic echinoderms and decapod crustaceans increased after the mid?1980s, coincident with a rise in North Sea sea surface temperature, whereas bivalve larvae underwent a reduction (Kirby et al., 2008). An increase in temperature may alter larval supply and in the long-term, and over large spatial scales, may result in changes in community composition.

Temperature cues may also influence the timing of gametogenesis and spawning in several species present in the biotope. Many polychaete species recruit in spring/early summer (Sardá et al., 1999).

Infaunal species are likely to be protected to some extent from direct effects of acute increases in temperature by sediment buffering, although increased temperatures may affect infauna indirectly by stimulating increased bacterial activity and increased oxygen consumption. Emery et al. (1957) reported that Nephtys spp. could withstand summer temperatures of 30-35 °C so is likely to withstand the benchmark acute temperature increase. An acute increase in temperature at the benchmark level may result in physiological stress endured by the infaunal species but is unlikely to lead to mortality. Nephtys cirrosa is an active worm which can swim short distances with an undulatory movement and therefore seek preferred conditions. Furthermore, other polychaetes species associated with the biotope may have wide global distributions. Glycera lapidum is found in the north-eastern Atlantic, Mediterranean, North Sea, Skagerrak and Kattegat (Marine Species Identification Portal).

Sensitivity assessment. Little evidence was available to assess this pressure. Assemblages in sands that contain many of the characterizing species may experience temperatures that are higher than experienced in the UK. It is considered likely, therefore, that chronic and acute changes in temperature at the pressure benchmark would be tolerated by species with a wide distribution or that some species or groups of species would be resistant. Biotope resistance and resilience are therefore assessed as 'High'. Biotope sensitivity is therefore assessed as ‘Not Sensitive’. 

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Not sensitive
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Temperature decrease (local) [Show more]

Temperature decrease (local)

Benchmark. A 5°C decrease in temperature for one month, or 2°C for one year. Further detail

Evidence

Polychaetes and other species associated with the biotope may have wide global distributions. Glycera lapidum is found in the north-eastern Atlantic, Mediterranean, North Sea, Skagerrak and Kattegat (Marine Species Identification Portal). Nephtys cirrosa reaches its northern limit in Scotland, and German Bight of the North Sea. A decrease in temperature is likely to result in loss of the species from the biotope in these areas.

Long‐term analysis of the North Sea pelagic system has identified yearly variations in larval abundance of Echinodermata, Arthropoda, and Mollusca larvae that correlate with sea surface temperatures. Larvae of benthic echinoderms and decapod crustaceans increased after the mid‐1980s, coincident with a rise in North Sea sea surface temperature, whereas bivalve larvae underwent a reduction (Kirby et al., 2008). A decrease in temperature may alter larval supply and in the long-term, and over large spatial scales, may result in changes in community composition.

Sensitivity assessment. Many of the characterizing species are found in more northern waters than the UK and may be adapted to colder temperatures. Plankton studies suggest that colder waters may favour bivalve larvae. An acute change may exceed thermal tolerances or lead to spawning or other biological effects. These effects may be sub-lethal or remove only a proportion of less tolerant species. Biotope resistance is therefore assessed as ‘Medium’ and resilience is assessed as ‘High’. Biotope sensitivity is therefore assessed as ‘Low’. 

Medium
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Low
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Salinity increase (local) [Show more]

Salinity increase (local)

Benchmark. A increase in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

No directly relevant evidence was found to assess this pressure. The biotope occurs in full salinity but is also found in the outer reaches of estuaries where some salinity fluctuations may be experienced so that the characterizing species may tolerate some changes in salinity. A study from the Canary Islands indicates that exposure to high salinity effluents (47- 50 psu) from desalination plants altered the structure of biological assemblages, reducing species richness and abundance (Riera et al., 2012). Bivalves and amphipods appeared to be less tolerant of increased salinity than polychaetes and were largely absent at the point of discharge. Polychaetes, including species or genera that occur in this biotope, such as Spio filicornis and Glycera spp. were present at the discharge point (Riera et al., 2012).

Nephtys cirrosa was most abundant in salinities >30 psu in the German Bight (south eastern North Sea) (Meißner et al., 2008), suggesting the species might be adversely affected by changes in salinity.

Sensitivity assessment. High saline effluents alter the structure of biological assemblages. Polychaete species may be more tolerant than bivalves but an increase in salinity is likely to result in declines in species richness and abundance based on Riera et al. (2012). Biotope resistance is assessed as ‘Low’ and resilience as ‘Medium’, as bivalve recovery may depend on episodic recruitment. Biotope sensitivity is assessed as ‘Medium’.

Low
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Medium
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Medium
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Salinity decrease (local) [Show more]

Salinity decrease (local)

Benchmark. A decrease in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

This biotope occurs in full salinity so it is unlikely that the species present experience salinity fluctuations so that the characterizing species may tolerate some changes in salinity. Nephtys species are tolerant of brackish waters and penetrate into the mouths of estuaries and estuarine lagoons where salinity may fall below 20 psu (Barnes, 1994), so are unlikely to be especially affected by a reduction in salinity.  

Sensitivity assessment. A reduction in salinity may result in changes in biotope composition as some sensitive species are lost and replaced by typical estuarine species more tolerant of the changed conditions. Biotope resistance is therefore assessed as ‘Low’ and resilience as ‘Medium’, as bivalve recovery may depend on episodic recruitment. Biotope sensitivity is assessed as ‘Medium’.

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Medium
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Medium
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Water flow (tidal current) changes (local) [Show more]

Water flow (tidal current) changes (local)

Benchmark. A change in peak mean spring bed flow velocity of between 0.1 m/s to 0.2 m/s for more than one year. Further detail

Evidence

This biotope is recorded in areas where tidal flow varies between strong (1.5-3.0 m/s) and moderately strong (0.5-1.5 m/s)  (JNCC, 2015). Sands and gravel are less cohesive than mud sediments and a change in water flow at the pressure benchmark may alter sediment transport patterns within the biotope. Hjulström (1939) concluded that fine sand (particle diameter of 0.3-0.6 mm) was easiest to erode and required a mean velocity of 0.2 m/s. Erosion and deposition of particles greater than 0.5 mm require a velocity >0.2 m/s to alter the habitat. The topography of this habitat is shaped by currents and wave action that influence the formation of ripples in the sediment. Specific fauna may be associated with troughs and crests of these bedforms and may form following an increase in water flow, or disappear following a reduction in flow.

Many of the species occur in a range of sediment types, which, given the link between hydrodynamics and sediment type, suggests that these species are not sensitive to changes in water flow at the pressure benchmark. Glycera spp. are found in areas with strong tidal streams where sediments are mobile (Roche et al., 2007) and in extremely sheltered areas (Connor et al., 2004).

Sensitivity assessment. This biotope occurs in areas subject to moderately strong water flows and these are a key factor maintaining the the physical structure of the habitat. Changes in water flow may alter the topography of the habitat and may cause some shifts in abundance. However, a change at the pressure benchmark (increase or decrease)  is unlikely to affect biotopes that occur in mid-range flows and biotope sensitivity is therefore assessed as ‘High’ and resilience is assessed as ‘High’, so the biotope is considered to be ‘Not sensitive’.

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Not sensitive
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Emergence regime changes [Show more]

Emergence regime changes

Benchmark.  1) A change in the time covered or not covered by the sea for a period of ≥1 year or 2) an increase in relative sea level or decrease in high water level for ≥1 year. Further detail

Evidence

Changes in emergence are 'Not relevant' to this biotope which is restricted to fully subtidal habitats. 

Not relevant (NR)
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Not relevant (NR)
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Not relevant (NR)
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Wave exposure changes (local) [Show more]

Wave exposure changes (local)

Benchmark. A change in near shore significant wave height of >3% but <5% for more than one year. Further detail

Evidence

Polychaete species that burrow are protected within the sediment from wave action disturbance. Species in the biotope may be indirectly affected by changes in water movement where these impact the supply of food or larvae or other processes. The biotope occurs in the shallow infralittoral, in habitats that are very exposed, exposed and moderately exposed to wave action (JNCC, 2015). In the description of the biotope, Connor et al. (2004) suggest that continual or periodic sediment disturbance from wave action prevent the establishment of a more stable community. Wave action is therefore likely to be the main factor determining the physical character and species composition in the biotope. Consequently, a decrease in wave exposure is likely to allow for the development of a more stable community, leading to loss and/or reclassification of the biotope. An increase in wave exposure is unlikely to be relevant.

Sensitivity assessment. SS.SCS.ICS.Glap is defined by an energetic hydrographic regime. A decrease in wave exposure could potentially allow for the develpment of a more stable community leading to reclassification of the biotope to SS.SCS.ICS.MoeVen, for example, which is thought to be a more diverse version of SS.SCS.ICS.Glap (Connor et al., 2004). However, the biotope occurs in a range of wave exposures, and a change at the pressure benchmark level (3-5% in significant wave height) is considered to fall within the natural range experienced by the biotope, so that resistance and resilience are assessed as 'High', and the biotope is therefore classed as ‘Not Sensitive’.

High
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High
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Not sensitive
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Chemical Pressures

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ResistanceResilienceSensitivity
Transition elements & organo-metal contamination [Show more]

Transition elements & organo-metal contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

The capacity of bivalves to accumulate heavy metals in their tissues, far in excess of environmental levels, is well known. Reactions to sub-lethal levels of heavy metal stressors include siphon retraction, valve closure, inhibition of byssal thread production, disruption of burrowing behaviour, inhibition of respiration, inhibition of filtration rate, inhibition of protein synthesis and suppressed growth (see review by Aberkali & Trueman, 1985). It is therefore likely that characterizing species Spisula elliptica may also bioaccumulate heavy metals.

Polychaetes are regarded as relatively tolerant of heavy metals (Bryan, 1984). Bryan & Gibbs (1983) suggested that in populations of polychaetes exposed to heavy metal contamination for a long period, metal resistance could be acquired. For example, Nephtys hombergii from Restronguet Creek seemed able to regulate copper. The head end of the worm became blackened and x-ray microanalysis by Bryan & Gibbs (1983) indicated that this was caused by the deposition of copper sulphide in the body wall. In the same study, Bryan & Gibbs (1983) presented evidence that Nephtys hombergii from Restronguet Creek possessed increased tolerance to copper contamination. Specimens from the Tamar Estuary had a 96 h LC50 of 250 µg/l, whilst those from Restronguet Creek had a 96 h LC50 of 700 µg/l (35 psu; 13°C).

Not Assessed (NA)
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Not assessed (NA)
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Not assessed (NA)
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Hydrocarbon & PAH contamination [Show more]

Hydrocarbon & PAH contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Suchanek (1993) reviewed the effects of oil on bivalves. Generally, contact with oil causes an increase in energy expenditure and a decrease in feeding rate, resulting in less energy available for growth and reproduction. Sublethal concentrations of hydrocarbons also reduce byssal thread production (thus weakening attachment) and infaunal burrowing rates. Conan (1982) investigated the long-term effects of the Amoco Cadiz oil spill at St Efflam beach in France. The author commented that, in the long-term, the biotas most severely affected by oil spills are low energy sandy and muddy shores, bays and estuaries. In such places, populations of species with long and short-term life expectancies (e.g. Ampelisca sp.) either vanished or displayed long-term decline following the Amoco Cadiz oil spill. Polychaetes, however, including Nephtys hombergii, cirratulids and capitellids were largely unaffected. Other studies support the conclusion that polychaetes are generally a tolerant taxa. Hiscock et al. (2004; 2005, from Levell et al., 1989) described Glycera spp. as a very tolerant taxa, found in enhanced abundances in the transitional zone along hydrocarbon contamination gradients surrounding oil platforms. Nephtys species were amongst the fauna that was eradicated from sediments following the 1969 West Falmouth spill of Grade 2 diesel fuel documented by Sanders (1978).

Not Assessed (NA)
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Not assessed (NA)
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Not assessed (NA)
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Synthetic compound contamination [Show more]

Synthetic compound contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

The anti-parasite compound ivermectin is highly toxic to benthic polychaetes (Black et al., 1997; Collier & Pinn, 1998; Grant & Briggs, 1998, cited in Wilding & Hughes, 2010). OSPAR (2000) stated that, at that time, ivermectin was not licensed for use in mariculture but was incorporated into the feed as a treatment against sea lice at some farms. Ivermectin has the potential to persist in sediments, particularly fine-grained sediments at sheltered sites. Data from a farm in Galway, Ireland indicated that ivermectin was detectable in sediments adjacent to the farm at concentrations up to 6.8 μm/kg and to a depth of 9 cm (reported in OSPAR, 2000). Infaunal polychaetes have been affected by deposition rates of 78-780 mg ivermectin/m2. Boon et al. (1985) reported that Nephtys species in the North Sea accumulated organochlorines but, based on total sediment analyses, organochlorine concentrations in Nephtys species were not correlated with the concentrations in the (type of) sediment which they inhabited.

Not Assessed (NA)
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Not assessed (NA)
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Not assessed (NA)
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Radionuclide contamination [Show more]

Radionuclide contamination

Benchmark. An increase in 10µGy/h above background levels. Further detail

Evidence

No evidence was found to support an assessment at the pressure benchmark. Following the Fukushima Dai-ichi nuclear power plant accident in August 2013, radioactive cesium concentrations in invertebrates collected from the seabed were assessed. Concentrations in bivalves and gastropods were lower than in polychaetes (Sohtome et al., 2014). The data does not indicate that there were mortalities.

No evidence (NEv)
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No evidence (NEv)
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No evidence (NEv)
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Introduction of other substances [Show more]

Introduction of other substances

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

Not Assessed (NA)
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Not assessed (NA)
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Not assessed (NA)
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De-oxygenation [Show more]

De-oxygenation

Benchmark. Exposure to dissolved oxygen concentration of less than or equal to 2 mg/l for one week (a change from WFD poor status to bad status). Further detail

Evidence

Riedel et al. (2012) assessed the response of benthic macrofauna to hypoxia advancing to anoxia in the Mediterranean. The hypoxic and anoxic conditions were created for 3-4 days in a box that enclosed in-situ sediments. In general, molluscs were more resistant than polychaetes, with 90% surviving hypoxia and anoxia, whereas only 10% of polychaetes survived. Exposed individual Timoclea ovata and Tellina serrata survived the experiment but the exposed Glycera spp. died. In general epifauna were more sensitive than infauna, mobile species more sensitive than sedentary species and predatory species more sensitive than suspension and deposit feeders. The test conditions did not lead to the production of hydrogen sulphide which may have reduced mortalities compared to some observations.

Further evidence of sensitivity was available for some of the polychaete species associated with this biotope. Glycera alba was found to be able to tolerate periods of anoxia resulting from inputs of organic rich material from a wood pulp and paper mill in Loch Eil (Scotland) (Blackstock & Barnes, 1982). Nierman et al. (1990) reported changes in a fine sand community for the German Bight in an area with regular seasonal hypoxia. In 1983, oxygen levels were exceptionally low (<3 mg O2/l) in large areas and <1 mg O2/l in some areas. Species richness decreased by 30-50% and overall biomass fell. Spiophanes bombyx was found in small numbers at some, but not all areas, during the period of hypoxia. Once oxygen levels returned to normal Spiophanes bombyx increased in abundance; the evidence suggests that at least some individuals would survive hypoxic conditions.

Sensitivity assessment. Riedel et al. (2012) provide evidence on general sensitivity trends. The characterizing bivalves are likely to survive hypoxia at the pressure benchmark although the polychaetes present, particularly the mobile predatory species such as Glycera and Nephtys may be less tolerant. As the biotope is characterized by polychaetes, resistance is assessed as ‘Low’ and resilience as ‘High’ based on migration, water transport of adults and recolonization by pelagic larvae. Biotope sensitivity is assessed as ‘Medium’.

Low
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Medium
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Medium
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Nutrient enrichment [Show more]

Nutrient enrichment

Benchmark. Compliance with WFD criteria for good status. Further detail

Evidence

This pressure relates to increased levels of nitrogen, phosphorus and silicon in the marine environment compared to background concentrations. The pressure benchmark is set at compliance with Water Framework Directive (WFD) criteria for good status, based on nitrogen concentration (UKTAG, 2014).  

Not relevant (NR)
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Not relevant (NR)
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High
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Not sensitive
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Organic enrichment [Show more]

Organic enrichment

Benchmark. A deposit of 100 gC/m2/yr. Further detail

Evidence

The biotope occurs in areas experiencing frequent sediment disturbance, which leads to particle sorting, so in-situ primary production is likely to be restricted to microphytobenthos and some macroalgae. An input of organic matter would provide a food subsidy to the deposit feeding polychaetes.

Borja et al. (2000) and Gittenberger & Van Loon (2011) assigned Glycera alba, Glycera lapidum and Spiophanes bombyx to their AMBI Group III, defined as: ‘Species tolerant to excess organic matter enrichment. These species may occur under normal conditions, but their populations are stimulated by organic enrichment (slight unbalance situations)’.

Sensitivity assessment.  At the pressure benchmark, organic inputs are likely to represent a food subsidy for the associated deposit feeding species and are unlikely to significantly affect the structure of the biological assemblage or impact the physical habitat. Biotope sensitivity is therefore assessed as ‘High’ and resilience as ‘High’ (by default), and the biotope is therefore considered to be ‘Not Sensitive’.

High
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High
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Not sensitive
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Physical Pressures

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ResistanceResilienceSensitivity
Physical loss (to land or freshwater habitat) [Show more]

Physical loss (to land or freshwater habitat)

Benchmark. A permanent loss of existing saline habitat within the site. Further detail

Evidence

All marine habitats and benthic species are considered to have a resistance of ‘None’ to this pressure and to be unable to recover from a permanent loss of habitat (resilience is ‘Very Low’). Sensitivity within the direct spatial footprint of this pressure is therefore ‘High’. Although no specific evidence is described, confidence in this assessment is ‘High’ due to the incontrovertible nature of this pressure.

None
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High
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Very Low
High
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High
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High
High
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High
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Physical change (to another seabed type) [Show more]

Physical change (to another seabed type)

Benchmark. Permanent change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. Further detail

Evidence

The biotope is characterized by the sedimentary habitat (JNCC, 2015), so a change to an artificial or rock substratum would alter the character of the biotope leading to reclassification and the loss of the sedimentary community including the characterizing bivalves and polychaetes that live buried within the sediment.

Sensitivity assessment. Based on the loss of the biotope, resistance is assessed as ‘None’, recovery is assessed as ‘Very Low’ (as the change at the pressure benchmark is permanent), and sensitivity is assessed as ‘High’.

None
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Very Low
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High
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Physical change (to another sediment type) [Show more]

Physical change (to another sediment type)

Benchmark. Permanent change in one Folk class (based on UK SeaMap simplified classification). Further detail

Evidence

This biotope is found in medium to coarse sand with some gravel (JNCC, 2015). The change referred to at the pressure benchmark is a change in sediment classification (based on Long, 2006) rather than a change in the finer-scale original Folk categories (Folk, 1954). For coarse sediments, resistance is assessed based on a change to either mixed sediments or mud and sandy muds. 

Sediment type is a key factor structuring the biological assemblage present in the biotope. Surveys over sediment gradients and before-and-after impact studies from aggregate extraction sites where sediments have been altered indicate patterns in change. The biotope classification (JNCC, 2015) provides information on the sediment types where biotopes are found and indicate likely patterns in change if the sediment were to alter. Long-term alteration of sediment type to finer more unstable sediments was observed six years after aggregate dredging at moderate energy sites (Boyd et al., 2005). The on-going sediment instability was reflected in a biological assemblage composed largely of juveniles (Boyd et al., 2005).

Differences in biotope assemblages in areas of different sediment type are likely to be driven by pre and post recruitment processes. Sediment selectivity by larvae will influence levels of settlement and distribution patterns. Snelgrove et al. (1999) demonstrated that Spisula solidissima, selected coarse sand over muddy sand. The larvae selected sediments typical of adult habitats, however, some species were nonselective (Snelgrove et al., 1999) and presumably in unfavourable habitats post recruitment, mortality will result for species that occur in a restricted range of habitats. Some species may, however, be present in a range of sediments. Post-settlement migration and selectivity also occurred on small scales (Snelgrove et al., 1999). Nepthys cirrosa occurs in fine to coarser sands, with greatest abundance in the Belgium part of the North Sea recorded in medium grain sizes (Degraer et al., 2006). Abundance of Nephtys may therefore increase if sediments were to become finer.

Cooper et al. (2011) found that characterizing species from sand dominated sediments were equally likely to be found in gravel dominated sediments. A reduction in sediment coarseness may not result in loss of characterizing species and reclassification of the biotope.

Desprez (2000) found that a change of habitat to fine sands, from coarse sands and gravels (from deposition of screened sand following aggregate extraction), changed the biological communities present. Nephtys cirrosa dominated the fine sand community.

Sensitivity assessment. A change to finer, muddy and mixed sediments is likely to reduce the abundance of the characterizing species and allow colonization by other species. Changes in the sediment type may lead to biotope reclassification. Based on the loss of the biotope, resistance is assessed as ‘None’, recovery is assessed as ‘Very Low’ (as the change at the pressure benchmark is permanent) and sensitivity is assessed as ‘High’.

None
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Very Low
High
High
High
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High
High
High
High
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Habitat structure changes - removal of substratum (extraction) [Show more]

Habitat structure changes - removal of substratum (extraction)

Benchmark. The extraction of substratum to 30 cm (where substratum includes sediments and soft rock but excludes hard bedrock). Further detail

Evidence

A number of studies assess the impacts of aggregate extraction on sand and gravel habitats. Most of the animals that occur in this biotope are shallowly buried, for example, Glycymerids occur at the surface with the mantle margins exposed at the surface (Thomas, 1975).

Recovery of sediments will be site-specific and will be influenced by currents, wave action and sediment availability (Desprez, 2000). Except in areas of mobile sands, the process tends to be slow (Kenny & Rees, 1996; Desprez, 2000 and references therein). Boyd et al. (2005) found that in a site subject to long-term extraction (25 years), extraction scars were still visible after six years and sediment characteristics were still altered in comparison with reference areas with ongoing effects on the biota. The strongest currents are unable to transport gravel. A further implication of the formation of these depressions is a local drop in current strength associated with the increased water depth, resulting in deposition of finer sediments than those of the surrounding substrate (Desprez et al., 2010 and references therein). See the physical change pressure for assessment

Sensitivity assessment. Resistance is assessed as ‘None’ as extraction of the sediment will remove the characterizing and associated species present. Resilience is assessed as ‘Medium’ as some species may require longer than two years to re-establish (see resilience section) and sediments may need to recover (where exposed layers are different). Biotope sensitivity is therefore assessed as ‘Medium’.

None
High
High
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Medium
High
High
Medium
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Medium
High
High
Medium
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Abrasion / disturbance of the surface of the substratum or seabed [Show more]

Abrasion / disturbance of the surface of the substratum or seabed

Benchmark. Damage to surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Comparative studies between disturbed and undisturbed areas indicate that abrasion and disturbance from bottom trawling on coarse gravels and sands reduce abundance of organisms, biomass and species diversity (Collie et al., 1997). Undisturbed sites contain more calcareous tube worms, bryozoans and hydroids and small fragile polychaetes and brittlestars. Burrowing species such as Glycera lapidum may be unaffected by surface abrasion.

Mean response of infauna and epifauna communities to fishing activities is shown to be much more negative in mud and sand communities than other habitats (Collie et al., 2000). Nephtys cirrosa was found to be sensitive to experimental trawling disturbance over 18 months (Tuck et al., 1998). Nephtys cirrosa is also likely to be vulnerable to dredging but can probably accommodate limited sediment deposition from the dredging process (MES, 2010). However, the polychaete Nephtys cirrosa is adapted to life in unstable sediments and survives through rapid burrowing (McDermott, 1983, cited from Elliott et al., 1998). This characteristic is likely to protect this species from surface abrasion.

Sensitivity assessment. Abrasion is likely to damage epifauna and may damage a proportion of the characterizing infauna species. Biotope resistance is therefore assessed as ‘Medium’. Resilience is assessed as ‘High’ as opportunistic species are likely to recruit rapidly and some damaged characterizing species may recover or recolonize. Biotope sensitivity is assessed as ‘Low’.

Medium
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High
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High
High
Medium
High
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Low
High
Medium
Low
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Penetration or disturbance of the substratum subsurface [Show more]

Penetration or disturbance of the substratum subsurface

Benchmark. Damage to sub-surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Comparative studies between disturbed and undisturbed areas indicate that abrasion and disturbance from bottom trawling on coarse gravels and sands, reduce abundance of organisms, biomass and species diversity (Collie et al., 1997). Undisturbed sites contain more calcareous tube worms, bryozoans and hydroids and small fragile polychaetes and brittlestars.

Capasso et al. (2010) compared benthic survey datasets from 1895 and 2007 for an area in the English Channel. Small, mobile species such as amphipods and small errant and predatory polychaetes (NephtysGlycera) appeared to have increased (Capasso et al., 2010). The area is subject to beam trawling and scallop dredging and the observed species changes would correspond with predicted changes following physical disturbance.

Experiments in shallow, wave disturbed areas, using a toothed, clam dredge, found that deposit feeding polychaetes were more impacted than carnivorous species. Dredging resulted in reductions of >90% of Spiophanes bombyx  immediately post dredging compared with before impact samples and the population reduction persisting for 90 days (although results may be confounded by storm events within the monitoring period which caused sediment mobility).

Bergman & Hup (1992) carried out a pre and post-experimental investigation using a 12 m beam trawl. The area was trawled three times over 2 days and samples taken up to 2 weeks after trawling. Some benthic species showed a 10-65% reduction in density after trawling the area three times. There was a significant lowering of densities (40-60%) of polychaete worms, including Spiophanes bombyx.

Gilkinson et al. (1998) simulated the physical interaction of otter trawl doors with the seabed in a laboratory test tank using a full-scale otter trawl door model. Between 58% and 70% of the bivalves in the scour path that were originally buried were completely or partially exposed at the test bed surface. However, only two out of a total of 42 specimens showed major damage. The pressure wave associated with the otter door pushes small bivalves out of the way without damaging them. Where species can rapidly burrow and reposition (typically within species occurring in unstable habitats) before predation mortality rates will be relatively low.

Sensitivity assessment. The trawling studies and the comparative study by Capasso et al. (2010) suggest that the biological assemblage present in this biotope is characterized by species that are relatively tolerant of penetration and disturbance of the sediments. Either species are robust or buried within sediments or are adapted to habitats with frequent disturbance (natural or anthropogenic) and recover quickly. Biotope resistance is assessed as ‘Medium’ as some species will be displaced and may be predated or injured and killed. Biotope resilience is assessed as ‘High’. Biotope sensitivity is therefore assessed as ‘Low’.

Medium
High
High
Medium
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High
High
High
High
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Low
High
High
Medium
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Changes in suspended solids (water clarity) [Show more]

Changes in suspended solids (water clarity)

Benchmark. A change in one rank on the WFD (Water Framework Directive) scale e.g. from clear to intermediate for one year. Further detail

Evidence

A change in turbidity at the pressure benchmark is assessed as an increase from intermediate 10-100 mg/l to medium (100-300 mg/l) and a change to clear (<10 mg/l). An increase or decrease in turbidity may affect primary production in the water column and indirectly alter the availability of phytoplankton food available to species in filter feeding mode. However, phytoplankton will also be transported from distant areas and so the effect of increased turbidity may be mitigated to some extent. According to Widdows et al. (1979), growth of filter-feeding bivalves may be impaired at suspended particulate matter (SPM) concentrations >250 mg/l. Where Spisula elliptica, the abundance of this species may be affected.

Changes in turbidity and seston are not predicted to directly affect Glycera and Nephtys spp. which live within sediments.

Sensitivity assessment. No direct evidence was found to assess impacts on the characterizing and associated species. The characterizing, suspension feeding bivalves are not predicted to be sensitive to decreases in turbidity and may be exposed to, and tolerant of, short-term increases in turbidity following sediment mobilization by storms and other events. An increase in suspended solids, at the pressure benchmark may have negative impacts on growth and fecundity by reducing filter feeding efficiency and imposing costs on clearing. However, the key characterizing and denominated species Glycera is a scavanger/predator and is unlikely to be adversely affected by changes in suspended solids. Biotope resistance and resilience are therefore assessed as ‘High’ and and the biotope considered 'Not Sensitive'.

High
High
Medium
Low
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High
High
High
High
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Not sensitive
High
Medium
Low
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Smothering and siltation rate changes (light) [Show more]

Smothering and siltation rate changes (light)

Benchmark. ‘Light’ deposition of up to 5 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Addition of fine material will alter the character of this habitat by covering it with a layer of dissimilar sediment and will reduce suitability for the species associated with this feature. Recovery will depend on the rate of sediment mixing or removal of the overburden, either naturally or through human activities. Recovery to a recognisable form of the original biotope will not take place until this has happened, but it is likely to occur rapidily in this wave disturbed biotope, moderating the impact of this pressure. The rate of habitat restoration would be site-specific and would be influenced by the type of siltation and rate. Long-term or permanent addition of fine particles would lead to reclassification of this biotope type (see physical change pressures). The additions of silts to a Spisula solida bed in Waterford Harbour (Republic of Ireland) from earthworks further upstream, for example, reduced the extent of the bed (Fahy et al., 2003). No information was provided on the depth of any deposits.

Bijkerk (1988, results cited from Essink, 1999) indicated that the maximal overburden through which small bivalves could migrate was 20 cm in sand for Donax and approximately 40 cm in mud for Tellina sp. and approximately 50 cm in sand. Similarly, the author indicated that the maximal overburden through which Nephtys could migrate was 60 cm through mud and 90 cm through sand. No further information was available on the rates of survivorship or the time taken to reach the surface. Furthermore, Powilleit et al. (2009) studied the response of the polychaete Nephtys hombergii to smothering. This species successfully migrated to the surface of 32-41 cm deposited sediment layer of till or sand/till mixture and restored contact with the overlying water. The high escape potential could partly be explained by the heterogeneous texture of the till and sand/till mixture with ‘voids’. While crawling upward to the new sediment surfaces burrowing velocities of up to 20 cm/day were recorded for Nephtys hombergii.

The characterizing polychaetes Spio filicornis and Spiophanes bombyx were characterized by Gittenberger & Van Loon (2011) in their index of sedimentation tolerance as Group IV species: ‘Although they are sensitive to strong fluctuations in sedimentation, their populations recover relatively quickly and even benefit. This causes their population sizes to increase significantly in areas after a strong fluctuation in sedimentation’ (Gittenberger & Van Loon, 2011). Glycera alba and Glycera lapidum were categorized as AMBI sedimentation Group II: 'Species sensitive to high sedimentation. They prefer to live in areas with some sedimentation, but don’t easily recover from strong fluctuations in sedimentation' (Gittenberger & Van Loon, 2011).

Sensitivity assessment. This biotope is exposed to tidal streams which may remove some sediments, but the bivalves and polychaetes are likely to be able to survive short periods under sediments and to reposition. However, as the pressure benchmark refers to fine material, this may be cohesive and species characteristic of sandy habitats may be less adapted to move through this than sands. Biotope resistance is assessed as 'Medium' as some mortality of characterizing and associated species may occur. Biotope resilience is assessed as 'High' and biotope sensitivity is assessed as 'Low'. 

Medium
High
High
Medium
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High
High
Low
Medium
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Low
High
Low
Medium
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Smothering and siltation rate changes (heavy) [Show more]

Smothering and siltation rate changes (heavy)

Benchmark. ‘Heavy’ deposition of up to 30 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Bijkerk (1988, results cited from Essink, 1999) indicated that the maximal overburden through which small bivalves could migrate was 20 cm in sand for Donax and approximately 40 cm in mud for Tellina sp. and approximately 50 cm in sand. Similarly, the author indicated that the maximal overburden through which Nephtys could migrate was 60 cm through mud and 90 cm through sand. No further information was available on the rates of survivorship or the time taken to reach the surface. Furthermore, Powilleit et al. (2009) studied the response of the polychaete Nephtys hombergii to smothering. This species successfully migrated to the surface of 32-41 cm deposited sediment layer of till or sand/till mixture and restored contact with the overlying water. The high escape potential could partly be explained by the heterogeneous texture of the till and sand/till mixture with ‘voids’. While crawling upward to the new sediment surfaces burrowing velocities of up to 20 cm/day were recorded for Nephtys hombergii.

Sensitivity assessment. Beyond re-establishing burrow openings or moving up through the sediment, there is evidence of synergistic effects on burrowing activity of marine benthos and mortality with changes in time of burial, sediment depth, sediment type and temperature (Maurer et al., 1986). Bivalve and polychaete species have been reported to migrate through depositions of sediment greater that the benchmark (30 cm of fine material added to the seabed in a single discrete event) (Bijkerk, 1988; Powilleit et al., 2009; Maurer et al., 1982). However, the character of the overburden is an important factor determining the degree of vertical migration of buried bivalves and polychaetes, and it is not clear whether the characterizing species are likely to be able to migrate through a maximum thickness of fine sediment because muds tend to be more cohesive and compacted than sand. Some mortality of the characterizing species is likely to occur. Resistance is assessed as ‘Low’ as few individuals are likely to reposition. Resilience is assessed as ‘Medium’ and sensitivity is assessed as ‘Medium’.

Low
High
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Medium
High
Low
Medium
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Medium
High
Low
Low
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Litter [Show more]

Litter

Benchmark. The introduction of man-made objects able to cause physical harm (surface, water column, seafloor or strandline). Further detail

Evidence

Not assessed.

Not Assessed (NA)
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Not assessed (NA)
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Not assessed (NA)
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NR
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Electromagnetic changes [Show more]

Electromagnetic changes

Benchmark. A local electric field of 1 V/m or a local magnetic field of 10 µT. Further detail

Evidence

No evidence.

No evidence (NEv)
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No evidence (NEv)
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No evidence (NEv)
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Underwater noise changes [Show more]

Underwater noise changes

Benchmark. MSFD indicator levels (SEL or peak SPL) exceeded for 20% of days in a calendar year. Further detail

Evidence

Not relevant.

Not relevant (NR)
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Not relevant (NR)
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Not relevant (NR)
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Introduction of light or shading [Show more]

Introduction of light or shading

Benchmark. A change in incident light via anthropogenic means. Further detail

Evidence

Invertebrate species such as the bivalves and polychaetes may possess rudimentary eyes and be able to perceive light and dark. Changes in light levels are not considered likely to affect adult stages, although little evidence is available to support this conclusion. This pressures is therefore assessed as ‘Not relevant’. 

Not relevant (NR)
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NR
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Not relevant (NR)
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Not relevant (NR)
NR
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NR
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Barrier to species movement [Show more]

Barrier to species movement

Benchmark. A permanent or temporary barrier to species movement over ≥50% of water body width or a 10% change in tidal excursion. Further detail

Evidence

The key characterizing bivalve species produce pelagic larvae as do many of the polychaete species. Barriers that reduce the degree of tidal excursion may alter larval supply to suitable habitats from source populations. Conversely, the presence of barriers may enhance local population supply by preventing the loss of larvae from enclosed habitats. As the bivalve species characterizing the biotope are widely distributed and produce large numbers of larvae capable of long distance transport and survival, resistance to this pressure is assessed as 'High' and resilience as 'High' by default. This biotope is therefore considered to be 'Not sensitive'. Some species such as Spio filicornis that occur within the biotope have benthic dispersal strategies (via egg masses laid on the surface) and water transport is not a key method of dispersal over wide distances.

High
Low
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NR
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High
High
High
High
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Not sensitive
Low
Low
Low
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Death or injury by collision [Show more]

Death or injury by collision

Benchmark. Injury or mortality from collisions of biota with both static or moving structures due to 0.1% of tidal volume on an average tide, passing through an artificial structure. Further detail

Evidence

'Not relevant’ to seabed habitats. NB. Collision by grounding vessels is addressed under ‘surface abrasion'.

Not relevant (NR)
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Not relevant (NR)
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Not relevant (NR)
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Visual disturbance [Show more]

Visual disturbance

Benchmark. The daily duration of transient visual cues exceeds 10% of the period of site occupancy by the feature. Further detail

Evidence

'Not relevant'.

Not relevant (NR)
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Not relevant (NR)
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Not relevant (NR)
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NR
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Biological Pressures

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ResistanceResilienceSensitivity
Genetic modification & translocation of indigenous species [Show more]

Genetic modification & translocation of indigenous species

Benchmark. Translocation of indigenous species or the introduction of genetically modified or genetically different populations of indigenous species that may result in changes in the genetic structure of local populations, hybridization, or change in community structure. Further detail

Evidence

Key characterizing species within this biotope are not cultivated or translocated. This pressure is therefore considered ‘Not relevant’ to this biotope group.

Not relevant (NR)
NR
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Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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Introduction or spread of invasive non-indigenous species [Show more]

Introduction or spread of invasive non-indigenous species

Benchmark. The introduction of one or more invasive non-indigenous species (INIS). Further detail

Evidence

The American slipper limpet Crepidula fornicata was introduced to the UK and Europe in the 1870s from the Atlantic coasts of North America with imports of the eastern oyster Crassostrea virginica. It was recorded in Liverpool in 1870 and the Essex coast in 1887-1890. It has spread through expansion and introductions along the full extent of the English Channel and into the European mainland (Blanchard, 1997, 2009; Bohn et al., 2012, 2013a, 2013b, 2015; De Montaudouin et al., 2018; Helmer et al., 2019; Hinz et al., 2011; McNeill et al., 2010; Powell-Jennings & Calloway, 2018; Preston et al., 2020; Stiger-Pouvreau & Thouzeau, 2015).

Crepidula fornicata is recorded from shallow, sheltered bays, lagoons and estuaries or the sheltered sides of islands, in variable salinity (18 to 40) although it prefers ca 30 (Tillin et al., 2020). Larvae require hard substrata for settlement. It prefers muddy gravelly, shell-rich, substrata that include gravel, or shells of other Crepidula, or other species e.g., oysters, and mussels. It is highly gregarious and seeks out adult shells for settlement, forming characteristic ‘stacks’ of adults. But it also recorded in a wide variety of habitats including clean sands, artificial substrata, Sabellaria alveolata reefs and areas subject to moderately strong tidal streams (Blanchard, 1997, 2009; Bohn et al., 2012, 2013a, 2013b, 2015; De Montaudouin et al., 2018; Hinz et al., 2011; Powell-Jennings & Calloway, 2018; Preston et al., 2020; Stiger-Pouvreau & Thouzeau, 2015; Tillin et al., 2020). 

High densities of Crepidula fornicata cause ecological impacts on sedimentary habitats. The species can form dense carpets that can smother the seabed in shallow bays, changing and modifying the habitat structure. At high densities, the species physically smothers the sediment, and the resultant build-up of silt, pseudofaeces, and faeces is deposited and trapped within the bed (Tillin et al., 2020, Fitzgerald, 2007, Blanchard, 2009, Stiger-Pouvreau & Thouzeau, 2015). The biodeposition rates of Crepidula are extremely high and once deposited, form an anoxic mud, making the environment suitable for other species, including most infauna (Blanchard, 2009; Stiger-Pouvreau & Thouzeau, 2015). For example, in fine sands, the community is replaced by a reef of slipper limpets, that provide hard substrata for sessile suspension-feeders (e.g., sea squirts, tube worms and fixed shellfish), while mobile carnivorous microfauna occupy species between or within shells, resulting in a homogeneous Crepidula dominated habitat (Blanchard, 2009). Blanchard (2009) suggested the transition occurred and became irreversible at 50% cover of the limpet. De Montaudouin et al. (2018) suggested that homogenization occurred above a threshold of 20-50 Crepidula /m2

Impacts on the structure of benthic communities will depend on the type of habitat that Crepidula colonizes. Few invasive non-indigenous species may be able to colonize mobile sands, due to the high levels of sediment disturbance. De Montaudouin & Sauriau (1999) reported that in muddy sediment dominated by deposit-feeders, species richness, abundance and biomass increased in the presence of high densities of Crepidula (ca 562 to 4772 ind./m2), in the Bay of Marennes-Oléron, presumably because the Crepidula bed provided hard substrata in an otherwise sedimentary habitat. In medium sands, Crepidula density was moderate (330-1300 ind./m2) but there was no significant difference between communities in the presence of Crepidula. Intertidal coarse sediment was less suitable for Crepidula with only moderate or low abundances (11 ind./m2) and its presence did not affect the abundance or diversity of macrofauna. However, there was a higher abundance of suspension–feeders and mobile Crustacea in the absence of Crepidula (De Montaudouin & Sauriau, 1999). The presence of Crepidula as an ecosystem engineer has created a range of new niche habitats, reducing biodiversity as it modifies habitats (Fitzgerald, 2007). De Montaudouin et al. (1999) concluded that Crepidula did not influence macroinvertebrate diversity or density significantly under experimental conditions, on fine sands in Arcachon Bay, France. De Montaudouin et al. (2018) noted that the limpet reef increased the species diversity in the bed, but homogenised diversity compared to areas where the limpets were absent. In the Milford Haven Waterway (MHW), the highest densities of Crepidula were found in areas of sediment with hard substrata, e.g., mixed fine sediment with shell or gravel or both (grain sizes 16-256 mm) but, while Crepidula density increased as gravel cover increased in the subtidal, the reverse was found in the intertidal (Bohn et al., 2015). Bohn et al. (2015) suggested that high densities of Crepidula in high-energy environments were possible in the subtidal but not the intertidal, suggesting the availability of this substratum type is beneficial for its establishment. Hinz et al. (2011) reported a substantial increase in the occurrence of Crepidula off the Isle of Wight, between 1958 and 2006, at a depth of ca 60 m, on hard substrata (gravel, cobbles, and boulders), swept by strong tidal streams. Presumably, Crepidula is more tolerant of tidal flow than the oscillatory flow caused by wave action which may be less suitable (Tillin et al., 2020). 

The colonial ascidian Didemnum vexillum is present in the UK but appears to be restricted to artificial surfaces such as pontoons, this species may, however, have the potential to colonize and smother offshore gravel habitats. Valentine et al. (2007) describe how Didemnum sp. have rapidly colonized gravel areas on the Georges Bank (US/Canada boundary). Colonies can coalesce to form large mats that may cover more than 50% of the seabed in parts. Areas of mobile sand, bordered communities of Didemnum sp. and these, therefore, do not appear to be suitable habitats (Valentine et al., 2007).

Although not currently established in UK waters, the whelk Rapana venosa may spread to UK habitats from Europe. Both Rapana venosa and the introduced oyster drill Urosalpinx cinerea predate on bivalves and could therefore negatively affect bivalve species.

Sensitivity assessment. The sediments characterizing this biotope are likely to be too mobile or otherwise unsuitable for most of the invasive non-indigenous species currently recorded in the UK. The above evidence suggests that Crepidula fornicata could colonize coarse sediment habitats in the subtidal, typical of this biotope. Bohn et al. (2015) demonstrated that Crepidula had a preference for gravelly habitats, while De Montaudouin & Sauriau (1999) and Bohn et al. (2015) noted that Crepidula densities were low in intertidal coarse sediments. Therefore, Crepidula has the potential to colonize, and modify the habitat and its associated community due to the introduction of Crepidula shell biomass, silt, pseudofaeces and faeces (Blanchard, 2009; Tillin et al., 2020), as occurs in maerl gravels (Grall & Hall-Spencer, 2003) resulting in the loss of the biotope. This habitat is very wave exposed to moderately exposed, in which wave action and storms may mobilise the sediment (JNCC, 2022), which may mitigate or prevent colonization by Crepidula at high densities, although Crepidula has been recorded from areas of strong tidal streams (Hinz et al., 2011). Therefore, the habitat may be more suitable for Crepidula where water movement is meditated by tidal flow rather than wave action, e.g., the deeper examples of the biotope, but Crepidula might not reach high densities. However, Crepidula reduced the density of suspension feeders and mobile Crustacea in coarse sediment even at low densities (De Montaudouin & Sauriau, 1999). 

Therefore, resistance is assessed as 'Medium', due to high wave action, subject to storms. Resilience is assessed as 'Very low' as it would require the removal of Crepidula, probably by artificial means. Hence, sensitivity is assessed as 'Medium' based on the worst-case scenario. Crepidula has not yet been reported to occur in this biotope so the confidence in the assessment is 'Low' and further evidence is required. Didemnum sp. and non-native predatory gastropods may also emerge as a threat to this biotope, although more mobile sands may exclude Didemnum

Medium
Low
NR
NR
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Very Low
High
High
High
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Medium
Low
NR
NR
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Introduction of microbial pathogens [Show more]

Introduction of microbial pathogens

Benchmark. The introduction of relevant microbial pathogens or metazoan disease vectors to an area where they are currently not present (e.g. Martelia refringens and Bonamia, Avian influenza virus, viral Haemorrhagic Septicaemia virus). Further detail

Evidence

No evidence was found for the characterizing polychaete species. Populations of bivalve species may be subject to a variety of diseases and parasites but evidence for the characterizing bivalves is limited. Berilli et al. (2000) conducted a parasitological survey of the bivalve Chamelea gallina in natural beds of the Adriatic Sea, where anomalous mortalities had been observed in 1997-1999. The occurrence of protozoans belonging to the families Porosporidae, Hemispeiridae and Trichodinidae was recorded. Porosporidae of the genus Nematopsis, present with 4 species, showed a prevalence of 100%. The results suggested that severe infections of protozoans of the genus Nematopsis could cause a not negligible respiratory sufferance, with a possible role in the decline of the natural banks of Chamelea gallina (Berilli et al., 2000).

Bacterial diseases are frequently found in molluscs during their larval stages, but seem to be relatively insignificant in populations of adult animals (Lόpez-Flores et al., 2004). This may be due to the primary defence mechanisms of molluscs, phagocytosis and encapsulation, which fight against small-sized pathogens, and whose resistance may be age related (Sindermann, 1990; Lόpez-Flores et al., 2004).

Sensitivity assessments. Pathogens may cause mortality and there may be a minor decline in species richness or abundance in the biotope. As there is no evidence for mass mortalities of characterizing species that would alter biotope classification biotope resistance is assessed as ‘Medium’. Biotope resilience is assessed as ‘High’ as changes may fall within natural population variability and a recognizable biotope is likely to be present after two years. Biotope sensitivity is therefore assessed as ‘Low’.

Medium
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High
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Low
High
High
Medium
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Removal of target species [Show more]

Removal of target species

Benchmark. Removal of species targeted by fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Nephtys cirrosa is targeted by bait digging. There is limited information on effect of digging directly on Nephtys cirrosa populations, however there is evidence on effects on another Nephtys species: Nephtys hombergii. Nephtys hombergii is directly removed through commercial bait digging and by recreational anglers and abundance significantly decreased in areas of the Solent, UK, where bait digging (primarily for Nereis virens) had occurred (Watson et al., 2007).

Recovery of Nephtys hombergii has been assessed to be very high as repopulation would occur initially relatively rapidly via adult migration and later by larval recruitment. Dittman et al. (1999) observed that Nephtys hombergii was amongst the macrofauna that colonized experimentally disturbed tidal flats within two weeks of the disturbance that caused defaunation of the sediment. However, if sediment is damaged recovery is likely to be slower, for instance Nephtys hombergii abundance was reduced by 50% in areas where tractor towed cockle harvesting was undertaken on experimental plots in Burry inlet, south Wales, and had not recovered after 86 days (Ferns et al., 2000).

Sensitivity assessment. Confidence in this assessment in relation to the removal of Nephtys cirrosa is low as it is based on evidence of removal of Nephtys hombergii. Resistance is ‘Low’ due to direct removal of a characterizing species, that on commercial scales can remove a large proportion of the population (for instance, Neves de Carvalho et al. (2013) calculated that bait digging activities in the Douro Estuary, Portugal may remove up to 9.9 tonnes of Hediste diversicolor). Resilience is assessed as ‘Medium’ as regions that are not regularly harvested may recover rapidly but continued harvesting will impact the population. Sensitivity is assessed as ‘Medium’. It is important to consider that the spatial extent and duration of harvesting is important to consider when assessing this pressure as smaller scale extraction may not impact the entire extent of the biotope but greater scale extraction over a long period would cause longer term impacts.

Low
Low
NR
NR
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Medium
High
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High
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Medium
Low
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NR
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Removal of non-target species [Show more]

Removal of non-target species

Benchmark. Removal of features or incidental non-targeted catch (by-catch) through targeted fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Species within the biotope are not functionally dependent on each other, although biological interactions will play a role in structuring the biological assemblage through predation and competition. Removal of adults may support recruitment of juvenile bivalves by reducing competition for space and consumption of larvae. 

Removal of species would also reduce the ecological services provided by these species such as secondary production and nutrient cycling.

Sensitivity assessment. Species within the biotope are relatively sedentary or slow moving, although the infaunal position may protect some burrowing species from removal. Biotope resistance is therefore assessed as ‘Low’ and resilience as ‘High’, as the habitat is likely to be directly affected by removal and some species will recolonize rapidly. Some variability in species recruitment, abundance and composition is natural and therefore a return to a recognizable biotope should occur within 2 years. Repeated chronic removal would, however, impact recovery. The biotope sensitivity is therefore considered 'Low'.

Low
High
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High
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Low
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Bibliography

  1. Aberkali, H.B. & Trueman, E.R., 1985. Effects of environmental stress on marine bivalve molluscs. Advances in Marine Biology, 22, 101-198.

  2. Allen, P.L. & Moore, J.J. 1987. Invertebrate macrofauna as potential indicators of sandy beach instability. Estuarine, Coastal and Shelf Science, 24, 109-125.

  3. Ballarin, L., Pampanin, D.M. & Marin, M.G., 2003. Mechanical disturbance affects haemocyte functionality in the Venus clam Chamelea gallina. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 136 (3), 631-640.

  4. Barnes, R.S.K., 1994. The brackish-water fauna of northwestern Europe. Cambridge: Cambridge University Press.

  5. Bergman, M.J.N. & Hup, M., 1992. Direct effects of beam trawling on macrofauna in a sandy sediment in the southern North Sea. ICES Journal of Marine Science, 49, 5-11. DOI https://doi.org/10.1093/icesjms/49.1.5

  6. Berrilli, F., Ceschia, G., De Liberato, C., Di Cave, D. & Orecchia, P., 2000. Parasitic infections of Chamelea gallina (Mollusca, Bivalvia) from commercially exploited banks of the Adriatic Sea. Bulletin of European Association of Fish Pathologists, 20 (5), 199-205.

  7. Bijkerk, R., 1988. Ontsnappen of begraven blijven: de effecten op bodemdieren van een verhoogde sedimentatie als gevolg van baggerwerkzaamheden: literatuuronderzoek: RDD, Aquatic ecosystems.

  8. Black, K.D., Fleming, S. Nickell, T.D. & Pereira, P.M.F. 1997. The effects of ivermectin, used to control sea lice on caged farmed salmonids, on infaunal polychaetes. ICES Journal of Marine Science, 54, 276-279.

  9. Blackstock, J. & Barnes, M., 1982. The Loch Eil project: biochemical composition of the polychaete, Glycera alba (Müller), from Loch Eil. Journal of Experimental Marine Biology and Ecology, 57 (1), 85-92.

  10. Blanchard, M., 2009. Recent expansion of the slipper limpet population (Crepidula fornicata) in the Bay of Mont-Saint-Michel (Western Channel, France). Aquatic Living Resources, 22 (1), 11-19. DOI https://doi.org/10.1051/alr/2009004

  11. Blanchard, M., 1997. Spread of the slipper limpet Crepidula fornicata (L.1758) in Europe. Current state and consequences. Scientia Marina, 61, Supplement 9, 109-118. Available from: http://scimar.icm.csic.es/scimar/index.php/secId/6/IdArt/290/

  12. Bohn, K., Richardson, C. & Jenkins, S., 2012. The invasive gastropod Crepidula fornicata: reproduction and recruitment in the intertidal at its northernmost range in Wales, UK, and implications for its secondary spread. Marine Biology, 159 (9), 2091-2103. DOI https://doi.org/10.1007/s00227-012-1997-3

  13. Bohn, K., Richardson, C.A. & Jenkins, S.R., 2015. The distribution of the invasive non-native gastropod Crepidula fornicata in the Milford Haven Waterway, its northernmost population along the west coast of Britain. Helgoland Marine Research, 69 (4), 313.

  14. Bohn, K., Richardson, C.A. & Jenkins, S.R., 2013a. Larval microhabitat associations of the non-native gastropod Crepidula fornicata and effects on recruitment success in the intertidal zone. Journal of Experimental Marine Biology and Ecology, 448, 289-297. DOI https://doi.org/10.1016/j.jembe.2013.07.020

  15. Bohn, K., Richardson, C.A. & Jenkins, S.R., 2013b. The importance of larval supply, larval habitat selection and post-settlement mortality in determining intertidal adult abundance of the invasive gastropod Crepidula fornicata. Journal of Experimental Marine Biology and Ecology, 440, 132-140. DOI https://doi.org/10.1016/j.jembe.2012.12.008

  16. Boon, J.P., Zantvoort, M.B., Govaert, M.J.M.A. & Duinker, J.C ., 1985. Organochlorines in benthic polychaetes (Nephtys spp.) and sediments from the southern North Sea. Identification of individual PCB components. Netherlands Journal of Sea Research, 19, 93-109.

  17. Borja, A., Franco, J. & Perez, V., 2000. A marine biotic index to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. Marine Pollution Bulletin, 40 (12), 1100-1114.

  18. Boyd, S., Limpenny, D., Rees, H. & Cooper, K., 2005. The effects of marine sand and gravel extraction on the macrobenthos at a commercial dredging site (results 6 years post-dredging). ICES Journal of Marine Science: Journal du Conseil, 62 (2), 145-162.

  19. Bryan, G.W. & Gibbs, P.E., 1983. Heavy metals from the Fal estuary, Cornwall: a study of long-term contamination by mining waste and its effects on estuarine organisms. Plymouth: Marine Biological Association of the United Kingdom. [Occasional Publication, no. 2.]

  20. Bryan, G.W., 1984. Pollution due to heavy metals and their compounds. In Marine Ecology: A Comprehensive, Integrated Treatise on Life in the Oceans and Coastal Waters, vol. 5. Ocean Management, part 3, (ed. O. Kinne), pp.1289-1431. New York: John Wiley & Sons.

  21. Cabioch, L., Dauvin, J.C. & Gentil, F., 1978. Preliminary observations on pollution of the sea bed and disturbance of sub-littoral communities in northern Brittany by oil from the Amoco Cadiz. Marine Pollution Bulletin, 9, 303-307.

  22. Capasso, E., Jenkins, S., Frost, M. & Hinz, H., 2010. Investigation of benthic community change over a century-wide scale in the western English Channel. Journal of the Marine Biological Association of the United Kingdom, 90 (06), 1161-1172.

  23. Chícharo, L., Chícharo, M., Gaspar, M., Regala, J. & Alves, F., 2002. Reburial time and indirect mortality of Spisula solida clams caused by dredging. Fisheries Research, 59, 247-257.

  24. Collie, J.S., Escanero, G.A. & Valentine, P.C., 1997. Effects of bottom fishing on the benthic megafauna of Georges Bank. Marine Ecology Progress Series, 155, 159-172. DOI https://doi.org/10.3354/meps155159

  25. Collie, J.S., Hall, S.J., Kaiser, M.J. & Poiner, I.R., 2000. A quantitative analysis of fishing impacts on shelf-sea benthos. Journal of Animal Ecology, 69 (5), 785–798.

  26. Collier, L.M. & Pinn, E.H., 1998. An assessment of the acute impact of the sea lice treatment Ivermectin on a benthic community. Journal of Experimental Marine Biology and Ecology, 230 (1), 131-147. DOI https://doi.org/10.1016/s0022-0981(98)00081-1

  27. Conan, G., 1982. The long-term effects of the Amoco Cadiz oil spill. Philosophical Transactions of the Royal Society of London B, 297, 323-333.

  28. Connor, D.W., Allen, J.H., Golding, N., Howell, K.L., Lieberknecht, L.M., Northen, K.O. & Reker, J.B., 2004. The Marine Habitat Classification for Britain and Ireland. Version 04.05. ISBN 1 861 07561 8. In JNCC (2015), The Marine Habitat Classification for Britain and Ireland Version 15.03. [2019-07-24]. Joint Nature Conservation Committee, Peterborough. Available from https://mhc.jncc.gov.uk/

  29. Cooper, K., Ware, S., Vanstaen, K. & Barry, J., 2011. Gravel seeding - A suitable technique for restoring the seabed following marine aggregate dredging? Estuarine, Coastal and Shelf Science, 91 (1), 121-132.

  30. Dauvin, J.C. & Gillet, P., 1991. Spatio-temporal variability in population structure of Owenia fusiformis Delle Chiaje (Annelida: Polychaeta) from the Bay of Seine (eastern English Channel). Journal of Experimental Marine Biology and Ecology, 152, 105-122.

  31. Dauvin, J.C., 1985. Dynamics and production of a population of Venus ovata (Pennant) (Mollusca-Bivalvia) of Morlaix Bay (western English Channel). Journal of Experimental Marine Biology and Ecology, 91, 109-123.

  32. Dauvin, J.C., 1988a. Structure and trophic organization of the Amphioxus lanceolatus - Venus fasciata community from the Bay of Morlaix (Brittany). Cahiers de Biologie Marine. Paris, 29, 163-185.

  33. Dauvin, J.C., 2000. The muddy fine sand Abra alba - Melinna palmata community of the Bay of Morlaix twenty years after the Amoco Cadiz oil spill. Marine Pollution Bulletin, 40, 528-536.

  34. Davenport, J. & Davenport, J.L., 2005. Effects of shore height, wave exposure and geographical distance on thermal niche width of intertidal fauna. Marine Ecology Progress Series, 292, 41-50.

  35. Davies, C.E. & Moss, D., 1998. European Union Nature Information System (EUNIS) Habitat Classification. Report to European Topic Centre on Nature Conservation from the Institute of Terrestrial Ecology, Monks Wood, Cambridgeshire. [Final draft with further revisions to marine habitats.], Brussels: European Environment Agency.

  36. De Montaudouin, X. & Sauriau, P.G., 1999. The proliferating Gastropoda Crepidula fornicata may stimulate macrozoobenthic diversity. Journal of the Marine Biological Association of the United Kingdom, 79, 1069-1077. DOI https://doi.org/10.1017/S0025315499001319

  37. De Montaudouin, X., Andemard, C. & Labourg, P-J., 1999. Does the slipper limpet (Crepidula fornicata L.) impair oyster growth and zoobenthos diversity ? A revisited hypothesis. Journal of Experimental Marine Biology and Ecology, 235, 105-124.

  38. De Montaudouin, X., Blanchet, H. & Hippert, B., 2018. Relationship between the invasive slipper limpet Crepidula fornicata and benthic megafauna structure and diversity, in Arcachon Bay. Journal of the Marine Biological Association of the United Kingdom, 98 (8), 2017-2028. DOI https://doi.org/10.1017/s0025315417001655

  39. Degraer, S., Wittoeck, J., Appeltans, W., Cooreman, K., Deprez, T., Hillewaert, H., Hostens, K., Mees, J., Vanden Berghe, E. & Vincx, M., 2006. The macrobenthos atlas of the Belgian part of the North Sea. Belgian Science Policy, Brussels.

  40. Desprez, M., 2000. Physical and biological impact of marine aggregate extraction along the French coast of the Eastern English Channel: short- and long-term post-dredging restoration. ICES Journal of Marine Science, 57 (5), 1428-1438.

  41. Desprez, M., 2000. Physical and biological impact of marine aggregate extraction along the French coast of the Eastern English Channel: short- and long-term post-dredging restoration. ICES Journal of Marine Science, 57 (5), 1428-1438.

  42. Desprez, M., Pearce, B. & Le Bot, S., 2010. The biological impact of overflowing sands around a marine aggregate extraction site: Dieppe (eastern English Channel). ICES Journal of Marine Science, 67, 270-277. DOI https://doi.org/10.1093/icesjms/fsp245

  43. Diaz-Castaneda, V., Richard, A. & Frontier, S., 1989. Preliminary results on colonization, recovery and succession in a polluted areas of the southern North Sea (Dunkerque's Harbour, France). Scientia Marina, 53, 705-716.

  44. Dittmann, S., 1999. Biotic interactions in a Lanice conchilega dominated tidal flat. In The Wadden Sea ecosystem, (ed. S. Dittmann), pp.153-162. Germany: Springer-Verlag.

  45. Elliot, M., Nedwell, S., Jones, N.V., Read, S.J., Cutts, N.D. & Hemingway, K.L., 1998. Intertidal sand and mudflats & subtidal mobile sandbanks (Vol. II). An overview of dynamic and sensitivity for conservation management of marine SACs. Prepared by the Scottish Association for Marine Science for the UK Marine SACs Project. Available from: http://ukmpa.marinebiodiversity.org/uk_sacs/pdfs/sandmud.pdf

  46. Emery, K.O., Stevenson, R.E., Hedgepeth, J.W., 1957. Estuaries and lagoons. In Treatise on marine ecology and paleoecology. vol. 1. Ecology, (ed. J.W. Hedgpeth), Geological Society of America, Memoir 67, pp. 673-750. Waverley Press, Baltimore, Mayland.

  47. Emson, R.H., Jones, M. & Whitfield, P., 1989. Habitat and latitude differences in reproductive pattern and life-history in the cosmopolitan brittle-star Amphipholis squamata (Echinodermata). In: Ryland, J.S., Tyler, P.A. (Eds.), Reproduction, Genetics and Distributions of Marine Organisms, pp. 75-81. Olsen & Olsen, Fredensborg.

  48. Essink, K., 1999. Ecological effects of dumping of dredged sediments; options for management. Journal of Coastal Conservation, 5, 69-80.

  49. Fahy, E., Carroll, J. & O'Toole, M., 2003. A preliminary account of fisheries for the surf clam Spisula solida (L) (Mactracea) in Ireland [On-line] http://www.marine.ie, 2004-03-16

  50. Ferns, P.N., Rostron, D.M. & Siman, H.Y., 2000. Effects of mechanical cockle harvesting on intertidal communities. Journal of Applied Ecology, 37, 464-474.

  51. FitzGerald, A., 2007. Slipper Limpet Utilisation and Management. Final Report. Port of Truro Oyster Management Group., Truro, 101 pp. Available from https://www.shellfish.org.uk/files/Literature/Projects-Reports/0701-Slipper_Limpet_Report_Final_Small.pdf

  52. Folk, R.L., 1954. The distinction between grain size and mineral composition in sedimentary-rock nomenclature. 62The Journal of Geology, 344-359.

  53. Ford, E., 1923. Animal communities of the level sea-bottom in the water adjacent to Plymouth. Journal of the Marine Biological Association of the United Kingdom, 13, 164-224.

  54. Fretter, V. & Graham, A., 1981. The Prosobranch Molluscs of Britain and Denmark. Part 6. Molluscs of Britain and Denmark. Part 6. Journal of Molluscan Studies, Supplement 9, 309-313.

  55. Frid, C.L., Harwood, K.G., Hall, S.J. & Hall, J.A., 2000. Long-term changes in the benthic communities on North Sea fishing grounds. ICES Journal of Marine Science, 57 (5), 1303.

  56. Gaspar, M.B. & Monteiro, C.C., 1999. Gametogenesis and spawning in the subtidal white clam Spisula solida, in relation to temperature. Journal of the Marine Biological Association of the United Kingdom, 79, 753-755.

  57. Gaspar, M.B., Leitão, F., Santos, M.N., Sobral, M., Chícharo, L., Chícharo, A. & Monteiro, C., 2002. Influence of mesh size and tooth spacing on the proportion of damaged organisms in the catches of the portuguese clam dredge fishery. ICES Journal of Marine Science, 59,1228-1236.

  58. Gaspar, M.B., Pereira, A.M., Vasconcelos, P. & Monteiro, C.C., 2004. Age and growth of Chamelea gallina from the Algarve coast (southern Portugal): influence of seawater temperature and gametogenic cycle on growth rate. Journal of Molluscan Studies, 70 (4), 371-377.

  59. Gentil, F., Dauvin, J.C. & Menard, F., 1990. Reproductive biology of the polychaete Owenia fusiformis Delle Chiaje in the Bay of Seine (eastern English Channel). Journal of Experimental Marine Biology and Ecology, 142, 13-23.

  60. Gibbs, P.E., Burt, G.R., Pascoe, P.L., Llewellyn, C.A. & Ryan K.P., 2000. Zinc, copper and chlorophyll-derivates in the polychaete Owenia fusiformis. Journal of the Marine Biological Association of the United Kingdom, 80, 235-248.

  61. Gilkinson, K., Paulin, M., Hurley, S. & Schwinghamer, P., 1998. Impacts of trawl door scouring on infaunal bivalves: results of a physical trawl door model/dense sand interaction. Journal of Experimental Marine Biology and Ecology, 224 (2), 291-312.

  62. Gilkinson, K.D., Gordon, D.C., MacIsaac, K.G., McKeown, D.L., Kenchington, E.L., Bourbonnais, C. & Vass, W.P., 2005. Immediate impacts and recovery trajectories of macrofaunal communities following hydraulic clam dredging on Banquereau, eastern Canada. ICES Journal of Marine Science: Journal du Conseil, 62 (5), 925-947.

  63. Giribet, G. & Peñas, A., 1999. Revision of the genus Goodallia (Bivalvia: Astartidae) with the description of two new species. Journal of Molluscan Studies, 65 (2), 251-265. DOI https://doi.org/10.1093/mollus/65.2.251

  64. Gittenberger, A. & Van Loon, W.M.G.M., 2011. Common marine macrozoobenthos species in the Netherlands, their characteristics and sensitivities to environmental pressures. GiMaRIS Report no 2011.08. DOI: https://doi.org/10.13140/RG.2.1.3135.7521

  65. Glémarec, M., 1973. The benthic communities of the European North Atlantic continental shelf. Oceanography and Marine Biology: an Annual Review, 11, 263-289.

  66. Grall J. & Hall-Spencer J.M. 2003. Problems facing maerl conservation in Brittany. Aquatic Conservation: Marine and Freshwater Ecosystems, 13, S55-S64. DOI https://doi.org/10.1002/aqc.568

  67. Grant, A. & Briggs, A.D., 1998. Toxicity of Ivermectin to estuarine and marine invertebrates. Marine Pollution Bulletin, 36 (7), 540-541. DOI https://doi.org/10.1016/S0025-326X(98)00012-5

  68. Guillou, J. & Sauriau, F.G., 1985. Some observations on the biology and ecology of a Venus striatula population in the Bay of Douarnenez, Brittany. Journal of the Marine Biological Association of the United Kingdom, 65, 889-900.

  69. Hauton, C., Hall-Spencer, J.M. & Moore, P.G., 2003. An experimental study of the ecological impacts of hydraulic bivalve dredging on maerl. ICES Journal of Marine Science, 60, 381-392.

  70. Hinz, H., Capasso, E., Lilley, M., Frost, M. & Jenkins, S.R., 2011. Temporal differences across a bio-geographical boundary reveal slow response of sub-littoral benthos to climate change. Marine Ecology Progress Series, 423, 69-82. DOI https://doi.org/10.3354/meps08963

  71. Hiscock, K., Langmead, O. & Warwick, R., 2004. Identification of seabed indicator species from time-series and other studies to support implementation of the EU Habitats and Water Framework Directives. Report to the Joint Nature Conservation Committee and the Environment Agency from the Marine Biological Association. Marine Biological Association of the UK, Plymouth. JNCC Contract F90-01-705. 109 pp.

  72. Hiscock, K., Langmead, O., Warwick, R. & Smith, A., 2005. Identification of seabed indicator species to support implementation of the EU Habitats and Water Framework Directives. Report to the Joint Nature Conservation Committee and the Environment Agency The Marine Biological Association, Plymouth, 77 pp.

  73. Hjulström, F., 1939. Transportation of detritus by moving water: Part 1. Transportation. Recent Marine Sediments, a Symposium (ed. P.D. Trask), pp. 5-31. Dover Publications, Inc.

  74. Holme, N.A., 1966. The bottom fauna of the English Channel. Part II. Journal of the Marine Biological Association of the United Kingdom, 46, 401-493.

  75. JNCC (Joint Nature Conservation Committee), 2022.  The Marine Habitat Classification for Britain and Ireland Version 22.04. [Date accessed]. Available from: https://mhc.jncc.gov.uk/

  76. JNCC (Joint Nature Conservation Committee), 2022.  The Marine Habitat Classification for Britain and Ireland Version 22.04. [Date accessed]. Available from: https://mhc.jncc.gov.uk/

  77. Joaquim, S., Gaspar, M.B., Matias, D., Ben-Hamadou, R. & Arnold, W.S., 2008. Rebuilding viable spawner patches of the overfished Spisula solida (Mollusca: Bivalvia): a preliminary contribution to fishery sustainability. ICES Journal of Marine Science: Journal du Conseil, 65 (1), 60-64.

  78. Jones, N.S., 1950. Marine bottom communities. Biological Reviews, 25, 283-313.

  79. Jones, N.S., 1951. The bottom fauna of the south of the Isle of Man. Journal of Animal Ecology, 20, 132-144.

  80. Kühne, S. & Rachor, E., 1996. The macrofauna of a stony sand area in the German Bight (North Sea). Helgoländer Meeresuntersuchungen, 50 (4), 433.

  81. Kaiser, M.J., & Spencer, B.E., 1994a. A preliminary assessment of the immediate effects of beam trawling on a benthic community in the Irish Sea. In Environmental impact of bottom gears on benthic fauna in relation to natural resources management and protection of the North Sea. (ed. S.J. de Groot & H.J. Lindeboom). NIOZ-Rapport, 11, 87-94.

  82. Kaschl, A. & Carballeira, A., 1999. Behavioural responses of Venerupis decussata (Linnaeus, 1758) and Venerupis pullastra (Montagu, 1803) to copper spiked marine sediments. Boletin. Instituto Espanol de Oceanografia, 15, 383-394.

  83. Kenny, A.J. & Rees, H.L., 1996. The effects of marine gravel extraction on the macrobenthos: results 2 years post-dredging. Marine Pollution Bulletin, 32 (8-9), 615-622.

  84. Kenny, A.J. & Rees, H.L., 1994. The effects of marine gravel extraction on the macrobenthos: early post dredging recolonisation. Marine Pollution Bulletin, 28, 442-447.

  85. Kinne, O. (ed.), 1984. Marine Ecology: A Comprehensive, Integrated Treatise on Life in Oceans and Coastal Waters.Vol. V. Ocean Management Part 3: Pollution and Protection of the Seas - Radioactive Materials, Heavy Metals and Oil. Chichester: John Wiley & Sons.

  86. Kirby, R.R., Beaugrand, G. & Lindley, J.A., 2008. Climate-induced effects on the meroplankton and the benthic-pelagic ecology of the North Sea. Limnology and Oceanography, 53 (5), 1805.

  87. Klawe, W.L. & Dickie, L.M., 1957. Biology of the bloodworm, Glycera dibranchiata Ehlers, and its relation to the bloodworm fishery of the Maritime Provinces. Bulletin of Fisheries Research Board of Canada, 115, 1-37.

  88. Kröncke, I., Dippner, J., Heyen, H. & Zeiss, B., 1998. Long-term changes in macrofaunal communities off Norderney (East Frisia, Germany) in relation to climate variability. Marine Ecology Progress Series, 167, 25-36.

  89. Kranz, P.M., 1974. The anastrophic burial of bivalves and its paleoecological significance. The Journal of Geology, 82 (2), 237-265.

  90. Le Bot, S., Lafite, R., Fournier, M., Baltzer, A. & Desprez, M., 2010. Morphological and sedimentary impacts and recovery on a mixed sandy to pebbly seabed exposed to marine aggregate extraction (Eastern English Channel, France). Estuarine, Coastal and Shelf Science89221-233.

  91. Leitão, F., Gaspar, M.B., Santos, M.N. & Monteiro, C.C., 2009. A comparison of bycatch and discard mortality in three types of dredge used in the Portuguese Spisula solida (solid surf clam) fishery. Aquatic Living Resources, 22 (1), 1-10.

  92. Levell, D., Rostron, D. & Dixon, I.M.T., 1989. Sediment macrobenthic communities from oil ports to offshore oilfields. In Ecological Impacts of the Oil Industry, Ed. B. Dicks. Chicester: John Wiley & Sons Ltd.

  93. Long, D., 2006. BGS detailed explanation of seabed sediment modified Folk classification. Available from: http://www.emodnet-seabedhabitats.eu/PDF/GMHM3_Detailed_explanation_of_seabed_sediment_classification.pdf

  94. Lopez-Flores I., De la Herran, R., Garrido-Ramos, M.A., Navas, J.I., Ruiz-Rejon, C. & Ruiz-Rejon, M., 2004. The molecular diagnosis of Marteilia refringens and differentiation between Marteilia strains infecting oysters and mussels based on the rDNA IGS sequence. Parasitology19 (4), 411-419.

  95. Mackie, A.S.Y., James, J.W.C., Rees, E.I.S., Darbyshire, T., Philpott, S.L., Mortimer, K., Jenkins, G.O. & Morando, A., 2006. BIOMÔR 4. The Outer Bristol Channel Marine Habitat Study. Studies in marine biodiversity and systematics from the National Museum of Wales, Cardiff. BIOMÔR Reports 4: 1–249 and A1–A227, + DVD-ROM (2007).

  96. Mackie, A.S.Y., Oliver, P.G. & Rees, E.I.S., 1995. Benthic biodiversity in the southern Irish Sea. Studies in Marine Biodiversity and Systematics from the National Museum of Wales. BIOMOR Reports, no. 1.

  97. Martínez, B., Arenas, F., Rubal, M., Burgués, S., Esteban, R., García-Plazaola, I., Figueroa, F., Pereira, R., Saldaña, L. & Sousa-Pinto, I., 2012. Physical factors driving intertidal macroalgae distribution: physiological stress of a dominant fucoid at its southern limit. Oecologia, 170 (2), 341-353.

  98. Maurer, D., Keck, R.T., Tinsman, J.C. & Leathem, W.A., 1982. Vertical migration and mortality of benthos in dredged material: Part III—Polychaeta. Marine Environmental Research, 6 (1), 49-68. DOI https://doi.org/10.1016/0141-1136(82)90007-1

  99. Maurer, D., Keck, R.T., Tinsman, J.C., Leatham, W.A., Wethe, C., Lord, C. & Church, T.M., 1986. Vertical migration and mortality of marine benthos in dredged material: a synthesis. Internationale Revue der Gesamten Hydrobiologie, 71, 49-63. DOI https://doi.org/10.1002/iroh.19860710106

  100. McCall, P.L., 1977. Community patterns and adaptive strategies of the infaunal benthos of Long Island Sound. Journal of Marine Research, 35, 221-266.

  101. McNeill, G., Nunn, J. & Minchin, D., 2010. The slipper limpet Crepidula fornicata Linnaeus, 1758 becomes established in Ireland. Aquatic Invasions, 5 (Suppl. 1), S21-S25. DOI https://doi.org/10.3391/ai.2010.5.S1.006

  102. Meißner, K., Darr, A. & Rachor, E., 2008. Development of habitat models for Nephtys species (Polychaeta: Nephtyidae) in the German Bight (North Sea). Journal of Sea Research, 60 (4), 276-291.

  103. Marine Ecological Surveys Limited (MES), 2008. Marine Macrofauna Genus Trait Handbook. Marine Ecological Surveys Limited: Bath. 

  104. MES, 2010. Marine Macrofauna Genus Trait Handbook. Marine Ecological Surveys Limited. http://www.genustraithandbook.org.uk/

  105. Morton, B., 2009. Aspects of the biology and functional morphology of Timoclea ovata (Bivalvia: Veneroidea: Venerinae) in the Azores, Portugal, and a comparison with Chione elevata (Chioninae). Açoreana, 6, 105-119.

  106. Moulaert, I. & Hostens, K., 2007. Post-extraction evolution of a macrobenthic community on the intensively extracted Kwintebank site in the Belgian part of the North Sea. CM Documents-ICES, (A:12).

  107. NBN, 2015. National Biodiversity Network 2015(20/05/2015). https://data.nbn.org.uk/

  108. Neves de Carvalho, A., Vaz, A.S.L., Sérgio, T.I.B. & Santos, P.J.T.d., 2013. Sustainability of bait fishing harvesting in estuarine ecosystems: Case study in the Local Natural Reserve of Douro Estuary, Portugal estuarinos: Caso de estudo na Reserva Natural Local do Estuário do Douro, Portugal. Revista de Gestão Costeira Integrada, 13 (2), 157-168.

  109. Nichols, F.H. & Thompson, J.K., 1985. Persistence of an introduced mudflat community in South San Francisco Bay, California. Marine Ecology Progress Series24, 83-97.

  110. Niermann, U., Bauerfeind, E., Hickel, W. & Westernhagen, H.V., 1990. The recovery of benthos following the impact of low oxygen content in the German Bight. Netherlands Journal of Sea Research, 25 (1), 215-226. DOI https://doi.org/10.1016/0077-7579(90)90023-A

  111. Olafsson, E.B. & Persson, L.E., 1986. The interaction between Nereis diversicolor (Muller) and Corophium volutator (Pallas) as a structuring force in a shallow brackish sediment. Journal of Experimental Marine Biology and Ecology, 103, 103-117.

  112. Olafsson, E.B., Peterson, C.H. & Ambrose, W.G. Jr., 1994. Does recruitment limitation structure populations and communities of macro-invertebrates in marine soft sediments: the relative significance of pre- and post-settlement processes. Oceanography and Marine Biology: an Annual Review, 32, 65-109

  113. OSPAR, 2000. OSPAR decision 2000/3 on the use of organic-phase drilling fluids (OPF) and the discharge of OPF-contaminated cuttings. Summary Record OSPAR 2000. OSPAR 00/20/1-E, Annex 18. Copenhagen, 26–30 June.

  114. Pearson, T.H. & Rosenberg, R., 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanography and Marine Biology: an Annual Review, 16, 229-311.

  115. Pedersen, M.F., Borum, J. & Fotel, L. F., 2009. Phosphorus dynamics and limitation of fast and slow-growing temperate seaweeds in Oslofjord, Norway. Marine Ecology Progress Series, 399, 103-115

  116. Petersen, C.G.J., 1918. The sea bottom and its production of fish food. A survey of the work done in connection with valuation of the Denmark waters from 1883-1917. Report of the Danish Biological Station, 25, 1-62.

  117. Poggiale, J.C. & Dauvin, J.C., 2001. Long term dynamics of three benthic Ampelisca (Crustacea - Amphipoda) populations from the Bay of Morlaix (western English Channel) related to their disappearance after the Amoco Cadiz oil spill. Marine Ecology Progress Series, 214, 201-209.

  118. Powell-Jennings, C. & Callaway, R., 2018. The invasive, non-native slipper limpet Crepidula fornicata is poorly adapted to sediment burial. Marine Pollution Bulletin, 130, 95-104. DOI https://doi.org/10.1016/j.marpolbul.2018.03.006

  119. Powilleit, M., Graf, G., Kleine, J., Riethmuller, R., Stockmann, K., Wetzel, M.A. & Koop, J.H.E., 2009. Experiments on the survival of six brackish macro-invertebrates from the Baltic Sea after dredged spoil coverage and its implications for the field. Journal of Marine Systems, 75 (3-4), 441-451.

  120. Preston, J., Fabra, M., Helmer, L., Johnson, E., Harris-Scott, E. & Hendy, I.W., 2020. Interactions of larval dynamics and substrate preference have ecological significance for benthic biodiversity and Ostrea edulis Linnaeus, 1758 in the presence of Crepidula fornicata. Aquatic Conservation: Marine and Freshwater Ecosystems, 30 (11), 2133-2149. DOI https://doi.org/10.1002/aqc.3446

  121. Price, H., 1982. An analysis of factors determining seasonal variation in the byssal attachment strength of Mytilus edulis. Journal of the Marine Biological Association of the United Kingdom, 62 (01), 147-155

  122. Rabalais, N.N., Harper, D.E. & Turner, R.E., 2001. Responses of nekton and demersal and benthic fauna to decreasing oxygen concentrations. In: Coastal Hypoxia Consequences for Living Resources and Ecosystems, (Edited by: Rabalais, N. N. and Turner, R. E.), Coastal and Estuarine Studies 58, American Geophysical Union, pp. 115–128. Washington D.C.

  123. Rhoads, D.C. & Young, D.K., 1970. The influence of deposit-feeding organisms on sediment stability and community trophic structure. Journal of Marine Research, 28, 150-178.

  124. Riedel, B., Zuschin, M. & Stachowitsch, M., 2012. Tolerance of benthic macrofauna to hypoxia and anoxia in shallow coastal seas: a realistic scenario. Marine Ecology Progress Series, 458, 39-52.

  125. Riera, R., Tuya, F., Ramos, E., Rodríguez, M. & Monterroso, Ó., 2012. Variability of macrofaunal assemblages on the surroundings of a brine disposal. Desalination, 291, 94-100.

  126. Roche, C., Lyons, D.O.,O'Connor, B. 2007. Benthic surveys of sandbanks in the Irish Sea. Irish Wildlife Manuals, No. 29. National Parks and Wildlife Service, Department of Environment, Heritage and Local Government, Dublin, Ireland.

  127. Rygg, B., 1985. Effect of sediment copper on benthic fauna. Marine Ecology Progress Series, 25, 83-89.

  128. Salzwedel, H., Rachor, E. & Gerdes, D., 1985. Benthic macrofauna communities in the German Bight. Verifflithungen des Institut fur Meeresforschung in Bremerhaven, 20, 199-267.

  129. Sanders, H.L., 1978. Florida oil spill impact on the Buzzards Bay benthic fauna: West Falmouth. Journal of the Fisheries Board of Canada, 35 (5), 717-730.

  130. Sardá, R., Pinedo, S. & Martin, D., 1999. Seasonal dynamics of macroinfaunal key species inhabiting shallow soft-bottoms in the Bay of Blanes (NW Mediterranean). Publications Elsevier: Paris.

  131. Sardá, R., Pinedo, S., Gremare, A. & Taboada, S., 2000. Changes in the dynamics of shallow sandy-bottom assemblages due to sand extraction in the Catalan Western Mediterranean Sea. ICES Journal of Marine Science, 57 (5), 1446-1453.

  132. Savina, M. & Pouvreau, S., 2004. A comparative ecophysiological study of two infaunal filter-feeding bivalves: Paphia rhomboıdes and Glycymeris glycymeris. Aquaculture, 239 (1), 289-306.

  133. Serrano, L., Cardell, M., Lozoya, J. & Sardá, R., 2011. A polychaete-dominated community in the NW Mediterranean Sea, 20 years after cessation of sewage discharges. Italian Journal of Zoology, 78 (sup1), 333-346.

  134. Simboura, N. & Zenetos, A., 2002. Benthic indicators to use in ecological quality classification of Mediterranean soft bottom marine ecosystems, including a new biotic index. Mediterranean Marine Science, 3 (2), 77-111.

  135. Sinderman, C.J., 1990. Principle diseases of marine fish and shellfish, 2nd edition, Volume 2. Diseases of marine shellfish. Academic Press, 521 pp.

  136. Snelgrove, P.V., Grassle, J.P., Grassle, J.F., Petrecca, R.F. & Ma, H., 1999. In situ habitat selection by settling larvae of marine soft‐sediment invertebrates. Limnology and Oceanography, 44 (5), 1341-1347.

  137. Sohtome, T., Wada, T., Mizuno, T., Nemoto, Y., Igarashi, S., Nishimune, A., Aono, T., Ito, Y., Kanda, J. & Ishimaru, T., 2014. Radiological impact of TEPCO's Fukushima Dai-ichi Nuclear Power Plant accident on invertebrates in the coastal benthic food web. Journal of Environmental Radioactivity, 138, 106-115.

  138. Somaschini, A., 1993. A Mediterranean fine-sand polychaete community and the effect of the tube-dwelling Owenia fusiformis Delle Chiaje on community structure. Internationale Revue de Gesamten Hydrobiologie, 78, 219-233.

  139. Stiger-Pouvreau, V. & Thouzeau, G., 2015. Marine Species Introduced on the French Channel-Atlantic Coasts: A Review of Main Biological Invasions and Impacts. Open Journal of Ecology, 5, 227-257. DOI https://doi.org/10.4236/oje.2015.55019

  140. Stirling, E.A., 1975. Some effects of pollutants on the behaviour of the bivalve Tellina tenuis. Marine Pollution Bulletin, 6, 122-124.

  141. Suchanek, T.H., 1993. Oil impacts on marine invertebrate populations and communities. American Zoologist, 33, 510-523. DOI https://doi.org/10.1093/icb/33.6.510

  142. Thomas, R., 1975. Functional morphology, ecology, and evolutionary conservatism in the Glycymerididae (Bivalvia). Palaeontology, 18 (2), 217-254.

  143. Thorson, G., 1957. Bottom communities (sublittoral or shallow shelf). Memoirs of the Geological Society of America, 67, 461-534.

  144. Tillin, H.M., Hiddink, J.G., Jennings, S. & Kaiser, M.J., 2006. Chronic bottom trawling alters the functional composition of benthic invertebrate communities on a sea-basin scale. Marine Ecology Progress Series, 318, 31-45.

  145. Tillin, H.M., Kessel, C., Sewell, J., Wood, C.A. & Bishop, J.D.D., 2020. Assessing the impact of key Marine Invasive Non-Native Species on Welsh MPA habitat features, fisheries and aquaculture. NRW Evidence Report. Report No: 454. Natural Resources Wales, Bangor, 260 pp. Available from https://naturalresourceswales.gov.uk/media/696519/assessing-the-impact-of-key-marine-invasive-non-native-species-on-welsh-mpa-habitat-features-fisheries-and-aquaculture.pdf

  146. Tuck, I.D., Hall, S.J., Robertson, M.R., Armstrong, E. & Basford, D.J., 1998. Effects of physical trawling disturbance in a previously unfished sheltered Scottish sea loch. Marine Ecology Progress Series, 162, 227-242.

  147. UKTAG, 2014. UK Technical Advisory Group on the Water Framework Directive [online]. Available from: http://www.wfduk.org

  148. Vader, W.J.M., 1964. A preliminary investigation in to the reactions of the infauna of the tidal flats to tidal fluctuations in water level. Netherlands Journal of Sea Research, 2, 189-222.

  149. Valentine, P.C., Carman, M.R., Blackwood, D.S. & Heffron, E.J., 2007. Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat. Journal of Experimental Marine Biology and Ecology, 342 (1), 109-121.

  150. Van Dalfsen, J.A., Essink, K., Toxvig Madsen, H., Birklund, J., Romero, J. & Manzanera, M., 2000. Differential response of macrozoobenthos to marine sand extraction in the North Sea and the Western Mediterranean. ICES Journal of Marine Science, 57 (5), 1439-1445.

  151. Vaudrey, J.M.P., Kremer, J.N., Branco, B.F. & Short, F.T., 2010. Eelgrass recovery after nutrient enrichment reversal. Aquatic Botany, 93 (4), 237-243.

  152. Veale, L.O., Hill, A.S., Hawkins, S.J. & Brand, A.R., 2000. Effects of long term physical disturbance by scallop fishing on subtidal epifaunal assemblages and habitats. Marine Biology, 137, 325-337.

  153. Warwick, R.M. & Davis, J.R., 1977. The distribution of sublittoral macrofauna communities in the Bristol Channel in relation to the substrate. Estuarine and Coastal Marine Science, 5, 267-288.

  154. Watson, G.J., Farrell, P., Stanton, S. & Skidmore, L.C., 2007. Effects of bait collection on Nereis virens populations and macrofaunal communities in the Solent, UK. Journal of the Marine Biological Association of the United Kingdom, 87 (3), 703-716.

  155. Widdows, J., Bayne, B.L., Livingstone, D.R., Newell, R.I.E. & Donkin, P., 1979. Physiological and biochemical responses of bivalve molluscs to exposure to air. Comparative Biochemistry and Physiology, 62A, 301-308.

  156. Wilding T. & Hughes D., 2010. A review and assessment of the effects of marine fish farm discharges on Biodiversity Action Plan habitats. Scottish Association for Marine Science, Scottish Aquaculture Research Forum (SARF).

  157. Woodin, S.A., 1978. Refuges, disturbance and community structure: a marine soft bottom example. Ecology, 59, 274-284.

  158. Zühlke, R., 2001. Polychaete tubes create ephemeral community patterns: Lanice conchilega (Pallas, 1766) associations studied over six years. Journal of Sea Research, 46, 261-272.

  159. Zühlke, R., Blome, D., van Bernem, K.H. & Dittmann, S., 1998. Effects of the tube-building polychaete Lanice conchilega (Pallas) on benthic macrofauna and nematodes in an intertidal sandflat. Senckenbergiana Maritima, 29, 131-138.

Citation

This review can be cited as:

Tillin, H.M. & Watson, A., 2023. Glycera lapidum in impoverished infralittoral mobile gravel and sand. In Tyler-Walters H. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29-03-2024]. Available from: https://www.marlin.ac.uk/habitat/detail/1137

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Last Updated: 06/09/2023