Cerianthus lloydii and other burrowing anemones in circalittoral muddy mixed sediment

Summary

UK and Ireland classification

Description

Circalittoral plains of sandy muddy gravel may be characterized by burrowing anemones such as Cerianthus lloydii. Other burrowing anemones such as Cereus pedunculatusMesacmaea mitchellii and Aureliania heterocera may be locally abundant. Relatively few conspicuous species are found in any great number in this biotope but typically they include ubiquitous epifauna such as Asterias rubensPagurus bernhardus and Liocarcinus depurator with occasional terebellid polychaetes such as Lanice conchilega and also the clam Pecten maximusOphiura albida may be frequent in some areas, and where surface shell or stones are present ascidians such as Ascidiella aspersa may occur in low numbers. (Information from Connor et al., 2004; JNCC, 2015).

Depth range

5-10 m, 10-20 m, 20-30 m

Additional information

-

Listed By

Sensitivity reviewHow is sensitivity assessed?

Sensitivity characteristics of the habitat and relevant characteristic species

The plains of sandy muddy gravel within SS.SMx.CMx.ClloMx are relatively sparse in species.  This biotope is characterized by burrowing anemones of which Cerianthus lloydii, is the most abundant species.  Other conspicuous species found in this biotope are mobile scavengers and predators including Callionymus lyra, Pagurus bernhardus and Asterias rubens.  Within the sub-biotope SS.SMx.CMx.ClloMx.Nem, the substratum includes more cobbles and pebbles, and the hydroids Nemertesia spp. have a high abundance and are characterizing species for this sub-biotope, in addition to Cerianthus lloydiiNemertesia spp. as well as some of the other hydroids can only attach themselves to a solid substratum, which is why they are missing from SS.SMx.CMx.ClloMx.  SS.SMx.CMx.ClloMx.Nem has greater species diversity than SS.SMx.CMx.ClloMx.  Therefore, the sensitivity of this biotope is based on the important characterizing species Cerianthus lloydii.  The mobile scavengers probably forage over a greater range than this biotope and are not assessed specifically.  The sensitivity of hydroids is mentioned where relevant to SS.SMx.CMx.ClloMx.Nem. 

Resilience and recovery rates of habitat

Little evidence was found to support this resilience assessment for Cerianthus lloydii.  MES (2010) suggested that the genus Cerianthus would be likely to have a low recovery rate following physical disturbance based on long-lifespan and slow growth rate.  No specific evidence was cited to support this conclusion.  The MES (2010) review also highlighted that there were gaps in information for this species and that age at sexual maturity and fecundity is unknown although the larvae are pelagic (MES 2010).  No empirical evidence was found for recovery rates following perturbations for Cerianthus lloydii.  This species has limited horizontal mobility and re-colonization via adults is unlikely (Tillin & Tyler-Walters, 2014).

Hydroids exhibit rapid rates of recovery from disturbance through repair, asexual reproduction, and larval colonization.  Sparks (1972) reviewed the regeneration abilities and rapid repair of injuries.  Fragmentation of the hydroid provides a route for short distance dispersal, for example, each fragmented part of Sertularia cupressina can regenerate itself following damage (Berghahn & Offermann, 1999). New colonies of the same genotype may, therefore, arise from damage to existing colonies (Gili & Hughes, 1995).  Many hydroid species also produce dormant, resting stages that are very resistant of environmental perturbation (Gili & Hughes 1995).  Colonies can be removed or destroyed; however, the resting stages may survive attached to the substratum and provide a mechanism for rapid recovery (Kosevich & Marfenin, 1986; Cornelius, 1995a).  The lifecycle of hydroids typically alternates between an attached solitary or colonial polyp generation and a free-swimming medusa generation.  Planulae larvae produced by hydroids typically metamorphose within 24 hours and crawl only a short distance away from the parent plant (Sommer, 1992).  Gametes liberated from the medusae (or vestigial sessile medusae) produce gametes that fuse to form zygotes and develop into free-swimming planula larvae (Hayward & Ryland, 1994) and are present in the water column between 2-20 days (Sommer, 1992).  Rafting on floating debris as dormant stages or reproductive adults (or on ships hulls or in ship ballast water), together with their potentially long lifespan, may have allowed hydroids to disperse over a wide area in the long-term and explain the near cosmopolitan distributions of many hydroid species (Cornelius, 1992; Boero & Bouillon 1993).  Hydroids are potential fouling organisms; rapidly colonizing a range of substrata placed in marine environments and are often the first organisms to colonize available space in settlement experiments (Gili & Hughes, 1995).  For example, hydroids were reported to colonize an experimental artificial reef within less than 6 months, becoming abundant in the following year (Jensen et al., 1994).  In similar studies, Obelia spp. recruited to the bases of reef slabs within three months and the slab surfaces within six months of the slabs being placed in the marine environment (Hatcher, 1998).  Cornelius (1992) stated that Obelia spp. could form large colonies within a matter of weeks. In a study of the long-term effects of scallop dredging in the Irish Sea, Bradshaw et al. (2002) noted that hydroids increased in abundance, presumably because of their regeneration potential, good local recruitment and ability to colonize newly exposed substratum quickly.  Cantero et al. (2002) describe fertility of Obelia dichotoma, Kirchenpaureria pinnata, Nemertesia ramosa in the Mediterranean as being year-round, whilst it should be noted that higher temperatures may play a factor in this year round fecundity.  Bradshaw et al. (2002) observed that reproduction in Nemertesia antennina occurred regularly, with three generations per year.  In addition, the presence of adults stimulated larval settlement, so that where adults remained, reproduction was likely to result in local recruitment.  Hayward & Ryland (1994) stated that medusae release in Obelia dichotoma occurred in summer.

The hydroids that are present within SS.SMx.CMx.ClloMx.Nem include Halecium halecinum, Nemertesia antennina, and Nemertesia ramosa.  Halecium halecinum is an erect hydroid growing up to 25 cm and is found on stones and shells in coastal areas.  It is widely distributed in the Atlantic and is present from Svalbard to the Mediterranean (Hayward & Ryland, 1994; Palerud et al., 2004; Medel et al., 1998).  Nemertesia anteninna grows up to 25 cm is found attached to shells and stones on sandy bottoms from the shallow sublittoral into deeper waters offshore, and is recorded in the northeast Atlantic, from at least the Faroes, the Barents Sea and Iceland south through Mauritania to southern Africa, including the Mediterranean, Azores and Madeira.  Nemertesia ramosa grows up to 15 cm, is found inshore to deeper water and is common throughout the British Isles, and is distributed from Iceland to north-west Africa (Hayward & Ryland, 1994).

Resilience assessment.  The characterizing species of interest are the burrowing anemone Cerianthus lloydii and the hydroid, Nemertesia antennina.  However, their presence strongly affects the designation of the biotope.  Hydroids, including Nemertesia antennina, are likely to recover from damage very quickly. Based on the available evidence, resilience for the hydroid species assessed is ‘High’ (recovery within two years) for any level of perturbation (where resistance is ‘None’, ‘Low’, ‘Medium’ or ‘High’). Therefore, the ability of both SS.SMx.CMx.ClloMx and SS.SMx.CMx.ClloMx.Nem to recover will depend on the ability of Cerianthus lloydii to recover.  However, there is very little information regarding the resilience of Cerianthus lloydii.  A resilience of ‘Medium’ (2 – 10 years) is suggested for all resistance levels (where resistance is ‘None’, ‘Low’, ‘Medium’) based on expert judgement.  Confidence in this assessment is 'Low', due to the lack of direct evidence for the characterizing species.

Note. 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.

Climate Change Pressures

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ResistanceResilienceSensitivity
Global warming (extreme) [Show more]

Global warming (extreme)

Extreme emission scenario (by the end of this century 2081-2100) benchmark of:

  • A 5°C rise in SST and NBT (coastal to the shelf seas),

  • A 6°C rise in surface air temperature (in eulittoral and supralittoral habitats).

  • A 1°C rise in Deep-sea habitats (>200 m) off the continental shelf, and

  • A 5°C rise in surface air temperature in intertidal habitats exclusive to Scotland. Further detail.

Evidence

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore. This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to the Bay of Biscay. Larvae, but not adults, have been recorded from the Mediterranean (De Kluijver et al., 2024). OBIS (2024) lists records of Cerianthus lloydii from sea surface temperatures of -5 to 20°C, although the majority of records were from 10 to15°C. Similarly, the majority of records for other burrowing anemones (Mesacmaea mitchellii and Cereus pedunclatus) are also between 10 to 15°C. Cerianthus lloydii is predominantly distributed in northern regions, and is likely to move further northward as the climate changes and temperature shifts out of its preferred range. There is no further information available on the temperature tolerance of Cerianthus lloydii.

Cerianthids can occur across wide temperature range (8.36 to 11.51°C) and depth ranges from shallow waters to deep-sea environments (238 to 1,070 m). Hydrozoans have been recorded in depths ranging to 8,400 m, indicating adaptations to varied thermal niches throughout the water column (Davies et al., 2014; Stepanjants & Chernyshev, 2015). However, there is limited evidence for thermal thresholds and thermal ranges were available for the characterizing species recorded in this biotope and large knowledge gaps limit current understanding of the ecological feedback that may occur to cerianthids as a result of climate change driven temperature increase.

Sensitivity assessment. Under the middle and high emission and extreme scenarios seawater temperatures are expected to temperatures rise by 3 to 5°C to potential southern summer temperatures of 23 to 24°C and northern summer temperatures of 17 to 19°C. The distribution of the important characterizing species Cerianthus lloydii suggest that they are probably resistant of chronic change in temperature for a year, but exposure to a short-term acute increase in temperature may cause Cerianthus lloydii to withdraw into their burrows temporarily. But most records of Cerianthus lloydii occur north of the Bay of Biscay so there is the possibility that it may be driven north or the greater depth to avoid ongoing climate mediated temperature increases. Therefore, for all three scenarios (middle and high emission and extreme scenarios) resistance is assessed as ‘Medium’ as a precaution. Resilience is assessed as ‘Very Low’ due to the long-term nature of ocean warming. This biotope is assessed as ‘Medium’ sensitivity to ocean warming under all three scenarios. However, there is limited evidence on thermal tolerances of the characterizing species recorded in this biotope and confidence in the assessment is ‘Low’.

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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Global warming (high) [Show more]

Global warming (high)

High emission scenario (by the end of this century 2081-2100) benchmark of:

  • A 4°C rise in SST, NBT (coastal to the shelf seas) and surface air temperature (in eulittoral and supralittoral habitats).

  • A 1°C rise in Deep-sea habitats (>200 m) off the continental shelf, and

  • A 3°C rise in surface air temperature in intertidal habitats exclusive to Scotland. Further detail.

Evidence

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore. This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to the Bay of Biscay. Larvae, but not adults, have been recorded from the Mediterranean (De Kluijver et al., 2024). OBIS (2024) lists records of Cerianthus lloydii from sea surface temperatures of -5 to 20°C, although the majority of records were from 10 to15°C. Similarly, the majority of records for other burrowing anemones (Mesacmaea mitchellii and Cereus pedunclatus) are also between 10 to 15°C. Cerianthus lloydii is predominantly distributed in northern regions, and is likely to move further northward as the climate changes and temperature shifts out of its preferred range. There is no further information available on the temperature tolerance of Cerianthus lloydii.

Cerianthids can occur across wide temperature range (8.36 to 11.51°C) and depth ranges from shallow waters to deep-sea environments (238 to 1,070 m). Hydrozoans have been recorded in depths ranging to 8,400 m, indicating adaptations to varied thermal niches throughout the water column (Davies et al., 2014; Stepanjants & Chernyshev, 2015). However, there is limited evidence for thermal thresholds and thermal ranges were available for the characterizing species recorded in this biotope and large knowledge gaps limit current understanding of the ecological feedback that may occur to cerianthids as a result of climate change driven temperature increase.

Sensitivity assessment. Under the middle and high emission and extreme scenarios seawater temperatures are expected to temperatures rise by 3 to 5°C to potential southern summer temperatures of 23 to 24°C and northern summer temperatures of 17 to 19°C. The distribution of the important characterizing species Cerianthus lloydii suggest that they are probably resistant of chronic change in temperature for a year, but exposure to a short-term acute increase in temperature may cause Cerianthus lloydii to withdraw into their burrows temporarily. But most records of Cerianthus lloydii occur north of the Bay of Biscay so there is the possibility that it may be driven north or the greater depth to avoid ongoing climate mediated temperature increases. Therefore, for all three scenarios (middle and high emission and extreme scenarios) resistance is assessed as ‘Medium’ as a precaution. Resilience is assessed as ‘Very Low’ due to the long-term nature of ocean warming. This biotope is assessed as ‘Medium’ sensitivity to ocean warming under all three scenarios. However, there is limited evidence on thermal tolerances of the characterizing species recorded in this biotope and confidence in the assessment is ‘Low’.

Medium
Low
NR
NR
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Very Low
High
High
High
Help
Medium
Low
NR
NR
Help
Global warming (middle) [Show more]

Global warming (middle)

Middle emission scenario (by the end of this century 2081-2100) benchmark of:

  • A 3°C rise in SST, NBT (coastal to the shelf seas) and surface air temperature (in eulittoral and supralittoral habitats).

  • A 1°C rise in Deep-sea habitats (>200 m) off the continental shelf.

  • A 2°C rise in surface air temperature in intertidal habitats exclusive to Scotland. Further detail.

Evidence

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore. This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to the Bay of Biscay. Larvae, but not adults, have been recorded from the Mediterranean (De Kluijver et al., 2024). OBIS (2024) lists records of Cerianthus lloydii from sea surface temperatures of -5 to 20°C, although the majority of records were from 10 to15°C. Similarly, the majority of records for other burrowing anemones (Mesacmaea mitchellii and Cereus pedunclatus) are also between 10 to 15°C. Cerianthus lloydii is predominantly distributed in northern regions, and is likely to move further northward as the climate changes and temperature shifts out of its preferred range. There is no further information available on the temperature tolerance of Cerianthus lloydii.

Cerianthids can occur across wide temperature range (8.36 to 11.51°C) and depth ranges from shallow waters to deep-sea environments (238 to 1,070 m). Hydrozoans have been recorded in depths ranging to 8,400 m, indicating adaptations to varied thermal niches throughout the water column (Davies et al., 2014; Stepanjants & Chernyshev, 2015). However, there is limited evidence for thermal thresholds and thermal ranges were available for the characterizing species recorded in this biotope and large knowledge gaps limit current understanding of the ecological feedback that may occur to cerianthids as a result of climate change driven temperature increase.

Sensitivity assessment. Under the middle and high emission and extreme scenarios seawater temperatures are expected to temperatures rise by 3 to 5°C to potential southern summer temperatures of 23 to 24°C and northern summer temperatures of 17 to 19°C. The distribution of the important characterizing species Cerianthus lloydii suggest that they are probably resistant of chronic change in temperature for a year, but exposure to a short-term acute increase in temperature may cause Cerianthus lloydii to withdraw into their burrows temporarily. But most records of Cerianthus lloydii occur north of the Bay of Biscay so there is the possibility that it may be driven north or the greater depth to avoid ongoing climate mediated temperature increases. Therefore, for all three scenarios (middle and high emission and extreme scenarios) resistance is assessed as ‘Medium’ as a precaution. Resilience is assessed as ‘Very Low’ due to the long-term nature of ocean warming. This biotope is assessed as ‘Medium’ sensitivity to ocean warming under all three scenarios. However, there is limited evidence on thermal tolerances of the characterizing species recorded in this biotope and confidence in the assessment is ‘Low’.

Medium
Low
NR
NR
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Very Low
High
High
High
Help
Medium
Low
NR
NR
Help
Marine heatwaves (high) [Show more]

Marine heatwaves (high)

High emission scenario benchmark: A marine heatwave occurring every two years, with a mean duration of 120 days, and a maximum intensity of 3.5°C. Further detail.

Evidence

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore. This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to the Bay of Biscay. Larvae, but not adults, have been recorded from the Mediterranean (De Kluijver et al., 2024). OBIS (2024) lists records of Cerianthus lloydii from sea surface temperatures of -5 to 20°C, although the majority of records were from 10 to 15°C. Similarly, the majority of records for other burrowing anemones (Mesacmaea mitchellii and Cereus pedunclatus) are also between 10 to 15°C. There is no further evidence available on the upper thermal limit of Cerianthus lloydii.

Sensitivity Assessment. Under the middle emission scenario, if heatwaves occurred every three years, with a maximum intensity of 2°C for 80 days by the end of this century, this could lead to summer sea temperatures reaching up to 24°C in southern England. Under the high emission scenario, if heatwaves occur every two years by the end of this century, reaching a maximum intensity of 3.5°C for 120 days, this could lead to the heatwave lasting the entire summer with temperatures reaching up to 26.5°C. As a precaution, this biotope has been assessed as having ‘Medium’ sensitivity to marine heatwaves. The recovery of Cerianthus lloydii populations is likely to be ‘Low’, hence, recovery may be interrupted by the occurrence of a further heatwave before the habitat can recover.  Therefore, resilience has been assessed as ‘Very Low’, leading to a sensitivity assessment of ‘Medium’ for this biotope, but with ‘Low’ confidence.

Medium
Low
NR
NR
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Very Low
High
High
High
Help
Medium
Low
NR
NR
Help
Marine heatwaves (middle) [Show more]

Marine heatwaves (middle)

Middle emission scenario benchmark:  A marine heatwave occurring every three years, with a mean duration of 80 days, with a maximum intensity of 2°C. Further detail.

Evidence

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore. This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to the Bay of Biscay. Larvae, but not adults, have been recorded from the Mediterranean (De Kluijver et al., 2024). OBIS (2024) lists records of Cerianthus lloydii from sea surface temperatures of -5 to 20°C, although the majority of records were from 10 to 15°C. Similarly, the majority of records for other burrowing anemones (Mesacmaea mitchellii and Cereus pedunclatus) are also between 10 to 15°C. There is no further evidence available on the upper thermal limit of Cerianthus lloydii.

Sensitivity Assessment. Under the middle emission scenario, if heatwaves occurred every three years, with a maximum intensity of 2°C for 80 days by the end of this century, this could lead to summer sea temperatures reaching up to 24°C in southern England. Under the high emission scenario, if heatwaves occur every two years by the end of this century, reaching a maximum intensity of 3.5°C for 120 days, this could lead to the heatwave lasting the entire summer with temperatures reaching up to 26.5°C. As a precaution, this biotope has been assessed as having ‘Medium’ sensitivity to marine heatwaves. The recovery of Cerianthus lloydii populations is likely to be ‘Low’, hence, recovery may be interrupted by the occurrence of a further heatwave before the habitat can recover.  Therefore, resilience has been assessed as ‘Very Low’, leading to a sensitivity assessment of ‘Medium’ for this biotope, but with ‘Low’ confidence.

Medium
Low
NR
NR
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Very Low
High
High
High
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Medium
Low
NR
NR
Help
Ocean acidification (high) [Show more]

Ocean acidification (high)

High emission scenario benchmark: a further decrease in pH of 0.35 (annual mean) and corresponding 120% increase in H+ ions , seasonal aragonite saturation of 20% of UK coastal waters and North Sea bottom waters, and the aragonite saturation horizon in the NE Atlantic, off the continental shelf, occurring at a depth of 400 m by the end of this century 2081-2100. Further detail 

Evidence

Increasing levels of CO2 in the atmosphere have led to the average pH of sea surface waters dropping from 8.25 in the 1700s to 8.14 in the 1990s (Jacobson, 2005). Decreased pH, and therefore shoaling of the calcium carbonate saturation horizon, may adversely impact UK sessile benthic communities (Danovaro et al., 2017). However, cerianthid anemones are not calcifying organisms, and therefore, may not be impacted by inhibited calcification due to pH decline. Furthermore, analyses that focused on taxa present in the North Atlantic indicated that deep-sea communities containing cerianthids may not be adversely impacted by ocean acidification (Johnson et al., 2018). Knowledge gaps and data paucity were highlighted as key limitations in the study, therefore, conclusive assessments of pH decline impacts to such communities could not be made (Johnson et al., 2018). There is no direct evidence regarding the effects of ocean acidification on Cerinthus lloydii or other burrowing anemones.

Ocean acidification has been documented to reduce calcification rates in some hydrocorals (de Barros Marangoni et al., 2017). In addition, hydrozoan metabolites required for cell protection from osmotic and thermal stress (betaine) have been found to be inhibited under extreme acidification (pH 7.7 to 7.75) as a result of climate change (Boco et al., 2019). In contrast, studies utilising over 40 years of Continuous Plankton Recorder (CPR) data from the North Sea have indicated a significant correlative relationship between increased hydrozoan abundance and a temporal pH decline of 0.2 (Attrill et al., 2007; Fabry et al., 2008). Furthermore, some hydrozoans have been indicated to have high tolerances to wide pH variability, exhibiting complete mortality at pH 4 and 10, and with high survival rates (>50%) within the pH range of 5 to 8.5 (Gutierre, 2012). However, tolerance ranges are likely to be species specific, therefore, it is possible that these findings cannot be inferred beyond the study.

Sensitivity Assessment. Cerianthids are not calcifying organisms, therefore, they are not considered to be impacted by the shoaling of the calcium carbonate saturation horizon due to ocean acidification (Danovaro et al., 2017). Ocean acidification may limit calcification in some hydrocorals and has also been attributed to inhibiting metabolic function in hydrozoan metabolites required for cell protection against osmotic and thermal stress. (Boco et al., 2019; de Barros Marangoni et al., 2017). However, these impacts may be species-specific. Conversely, some hydrozoans have been found to be highly tolerant to wide pH ranges and CPR data have indicated a significant correlative relationship between increased hydrozoan abundance and increased acidification in the North Sea (Attrill et al., 2007; Fabry et al., 2008; Gutierre, 2012).

Therefore, based on the evidence available, under both the middle and high emission scenarios resistance is assessed as ‘Medium’ to represent the possible impact on hydroids. Resilience is assessed as ‘Very Low’ as it is an ongoing long-term pressure, and sensitivity as ‘Medium’ at the benchmark level but with ‘Low’ confidence.

Medium
Low
NR
NR
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Very Low
High
High
High
Help
Medium
Low
NR
NR
Help
Ocean acidification (middle) [Show more]

Ocean acidification (middle)

Middle emission scenario benchmark: a further decrease in pH of 0.15 (annual mean) and corresponding 35% increase in H+ ions with no coastal aragonite undersaturation and the aragonite saturation horizon in the NE Atlantic, off the continental shelf, at a depth of 800 m by the end of this century 2081-2100. Further detail.

Evidence

Increasing levels of CO2 in the atmosphere have led to the average pH of sea surface waters dropping from 8.25 in the 1700s to 8.14 in the 1990s (Jacobson, 2005). Decreased pH, and therefore shoaling of the calcium carbonate saturation horizon, may adversely impact UK sessile benthic communities (Danovaro et al., 2017). However, cerianthid anemones are not calcifying organisms, and therefore, may not be impacted by inhibited calcification due to pH decline. Furthermore, analyses that focused on taxa present in the North Atlantic indicated that deep-sea communities containing cerianthids may not be adversely impacted by ocean acidification (Johnson et al., 2018). Knowledge gaps and data paucity were highlighted as key limitations in the study, therefore, conclusive assessments of pH decline impacts to such communities could not be made (Johnson et al., 2018). There is no direct evidence regarding the effects of ocean acidification on Cerinthus lloydii or other burrowing anemones.

Ocean acidification has been documented to reduce calcification rates in some hydrocorals (de Barros Marangoni et al., 2017). In addition, hydrozoan metabolites required for cell protection from osmotic and thermal stress (betaine) have been found to be inhibited under extreme acidification (pH 7.7 to 7.75) as a result of climate change (Boco et al., 2019). In contrast, studies utilising over 40 years of Continuous Plankton Recorder (CPR) data from the North Sea have indicated a significant correlative relationship between increased hydrozoan abundance and a temporal pH decline of 0.2 (Attrill et al., 2007; Fabry et al., 2008). Furthermore, some hydrozoans have been indicated to have high tolerances to wide pH variability, exhibiting complete mortality at pH 4 and 10, and with high survival rates (>50%) within the pH range of 5 to 8.5 (Gutierre, 2012). However, tolerance ranges are likely to be species specific, therefore, it is possible that these findings cannot be inferred beyond the study.

Sensitivity Assessment. Cerianthids are not calcifying organisms, therefore, they are not considered to be impacted by the shoaling of the calcium carbonate saturation horizon due to ocean acidification (Danovaro et al., 2017). Ocean acidification may limit calcification in some hydrocorals and has also been attributed to inhibiting metabolic function in hydrozoan metabolites required for cell protection against osmotic and thermal stress. (Boco et al., 2019; de Barros Marangoni et al., 2017). However, these impacts may be species-specific. Conversely, some hydrozoans have been found to be highly tolerant to wide pH ranges and CPR data have indicated a significant correlative relationship between increased hydrozoan abundance and increased acidification in the North Sea (Attrill et al., 2007; Fabry et al., 2008; Gutierre, 2012).

Therefore, based on the evidence available, under both the middle and high emission scenarios resistance is assessed as ‘Medium’ to represent the possible impact on hydroids. Resilience is assessed as ‘Very Low’ as it is an ongoing long-term pressure, and sensitivity as ‘Medium’ at the benchmark level but with ‘Low’ confidence.

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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Sea level rise (extreme) [Show more]

Sea level rise (extreme)

Extreme scenario benchmark: a 107 cm rise in average UK by the end of this century (2018-2100). Further detail.

Evidence

Sea-level rise is occurring through a combination of thermal expansion and ice melt. Sea levels have risen 1-3 mm yr-1 in the last century (Cazenave & Nerem, 2004, Church et al., 2004, Church & White, 2006). The most recent projections on sea-level rise suggest a rise of 50 cm under the middle emission scenario, 70 cm under the high emission scenario, and 107 cm under the extreme scenario.

This biotope occurs in areas sheltered from wave action and subject to weak or negligible tidal streams (Hughes, 1998a). Understanding of how sea-level rise will affect tidal energy, and the tide-swept nature of a habitat, is fraught with uncertainty, although evidence appears to suggest that any alterations will be non-linear (Pickering et al., 2012, Li et al., 2016). Modelling potential outcomes of sea-level rise on the tidal and residual currents in the Bohai Sea, China showed effects were site dependent, with energy either increasing or decreasing (Li et al., 2016). Similarly, Pickering et al. (2012) found a similar pattern around the UK for tidal amplitude. The effects of sea-level rise and increased wave action may be increased further due to storms and storms surges. IPCC (2019) note that the frequency of extreme sea-level events (e.g. due to storms) are predicted to increase as sea-level rises, however there is no consensus on the future storm and, hence, wave climate around UK coasts (Mossman et al., 2015; Lowe et al., 2018; Palmer et al., 2018).

Sensitivity assessment. This habitat occurs from 5 to 30 m, although Cerianthus lloydii has been recorded at depths ranging from 0 to 900 m (OBIS, 2024). Therefore, an increase in sea-level rise is unlikely to have a significant impact on this biotope. Therefore, resistance to sea-level rise has been assessed as ‘High’ for the middle (50 cm), and high (70 cm) emission scenario, and for the extreme scenario (107 cm). As no recovery is deemed necessary, resilience has been assessed as ‘High’, and therefore this species has been classified as ‘Not sensitive’ to sea-level rise at each of the benchmarks.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
NR
NR
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Sea level rise (high) [Show more]

Sea level rise (high)

High emission scenario benchmark: a 70 cm rise in average UK by the end of this century (2018-2100). Further detail.

Evidence

Sea-level rise is occurring through a combination of thermal expansion and ice melt. Sea levels have risen 1-3 mm yr-1 in the last century (Cazenave & Nerem, 2004, Church et al., 2004, Church & White, 2006). The most recent projections on sea-level rise suggest a rise of 50 cm under the middle emission scenario, 70 cm under the high emission scenario, and 107 cm under the extreme scenario.

This biotope occurs in areas sheltered from wave action and subject to weak or negligible tidal streams (Hughes, 1998a). Understanding of how sea-level rise will affect tidal energy, and the tide-swept nature of a habitat, is fraught with uncertainty, although evidence appears to suggest that any alterations will be non-linear (Pickering et al., 2012, Li et al., 2016). Modelling potential outcomes of sea-level rise on the tidal and residual currents in the Bohai Sea, China showed effects were site dependent, with energy either increasing or decreasing (Li et al., 2016). Similarly, Pickering et al. (2012) found a similar pattern around the UK for tidal amplitude. The effects of sea-level rise and increased wave action may be increased further due to storms and storms surges. IPCC (2019) note that the frequency of extreme sea-level events (e.g. due to storms) are predicted to increase as sea-level rises, however there is no consensus on the future storm and, hence, wave climate around UK coasts (Mossman et al., 2015; Lowe et al., 2018; Palmer et al., 2018).

Sensitivity assessment. This habitat occurs from 5 to 30 m, although Cerianthus lloydii has been recorded at depths ranging from 0 to 900 m (OBIS, 2024). Therefore, an increase in sea-level rise is unlikely to have a significant impact on this biotope. Therefore, resistance to sea-level rise has been assessed as ‘High’ for the middle (50 cm), and high (70 cm) emission scenario, and for the extreme scenario (107 cm). As no recovery is deemed necessary, resilience has been assessed as ‘High’, and therefore this species has been classified as ‘Not sensitive’ to sea-level rise at each of the benchmarks.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
NR
NR
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Sea level rise (middle) [Show more]

Sea level rise (middle)

Middle emission scenario benchmark: a 50 cm rise in average UK sea-level rise by the end of this century (2081-2100). Further detail.

Evidence

Sea-level rise is occurring through a combination of thermal expansion and ice melt. Sea levels have risen 1-3 mm yr-1 in the last century (Cazenave & Nerem, 2004, Church et al., 2004, Church & White, 2006). The most recent projections on sea-level rise suggest a rise of 50 cm under the middle emission scenario, 70 cm under the high emission scenario, and 107 cm under the extreme scenario.

This biotope occurs in areas sheltered from wave action and subject to weak or negligible tidal streams (Hughes, 1998a). Understanding of how sea-level rise will affect tidal energy, and the tide-swept nature of a habitat, is fraught with uncertainty, although evidence appears to suggest that any alterations will be non-linear (Pickering et al., 2012, Li et al., 2016). Modelling potential outcomes of sea-level rise on the tidal and residual currents in the Bohai Sea, China showed effects were site dependent, with energy either increasing or decreasing (Li et al., 2016). Similarly, Pickering et al. (2012) found a similar pattern around the UK for tidal amplitude. The effects of sea-level rise and increased wave action may be increased further due to storms and storms surges. IPCC (2019) note that the frequency of extreme sea-level events (e.g. due to storms) are predicted to increase as sea-level rises, however there is no consensus on the future storm and, hence, wave climate around UK coasts (Mossman et al., 2015; Lowe et al., 2018; Palmer et al., 2018).

Sensitivity assessment. This habitat occurs from 5 to 30 m, although Cerianthus lloydii has been recorded at depths ranging from 0 to 900 m (OBIS, 2024). Therefore, an increase in sea-level rise is unlikely to have a significant impact on this biotope. Therefore, resistance to sea-level rise has been assessed as ‘High’ for the middle (50 cm), and high (70 cm) emission scenario, and for the extreme scenario (107 cm). As no recovery is deemed necessary, resilience has been assessed as ‘High’, and therefore this species has been classified as ‘Not sensitive’ to sea-level rise at each of the benchmarks.

High
Low
NR
NR
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High
High
High
High
Help
Not sensitive
Low
NR
NR
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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

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore.  This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to Biscay.  Larvae, but not adults, have been recorded from the Mediterranean.  There is no further information available on the temperature tolerance of Cerianthus lloydii.

In a review of the ecology of hydroids, Gili & Hughes (1995) report that temperature is a critical factor stimulating or preventing reproduction and that most species have an optimal temperature for reproduction.  However, limited evidence for thermal thresholds and thermal ranges were available for the characterizing species recorded in this biotope.  Berrill (1949) reported that growth in Obelia commissularis (syn. dichotoma) was temperature dependent but ceased at 27°C.  Hydranths did not start to develop unless the temperature was less than 20°C and any hydranths under development would complete their development and rapidly regress at ca 25°C. Berrill (1948) reported that Obelia species were absent from a buoy in July and August during excessively high summer temperatures in Booth Bay Harbour, Maine, USA.  Berrill (1948) reported that the abundance of Obelia species and other hydroids fluctuated greatly, disappearing and reappearing as temperatures rose and fell markedly above and below 20°C during this period.  The upwelling of cold water (8-10°C colder than surface water) allowed colonies of Obelia sp. to form in large numbers.  Cantero et al. (2002) describe the presence and year-round fertility of Obelia dichotoma, Kirchenpaureria pinnata, Nemertesia ramosa and Halecium spp.in the Mediterranean, indicating probable tolerance to temperature increases at the benchmark level.

Sensitivity assessment.  At the level of the benchmark, a change in temperature is unlikely to have a negative impact on the biotope. Therefore, both the resistance and resilience are assessed as ‘High’, and sensitivity is assessed as ‘Not sensitive’ at the benchmark level.

High
Low
Medium
Medium
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High
High
High
High
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Not sensitive
Low
Medium
Medium
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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

Cerianthus lloydii adults are locally abundant in many localities on all coasts of the British Isles and in some areas are common on the shore.  This species occurs on all western coasts of Europe from Greenland and Spitzbergen south to Biscay.  No further information is available on the temperature tolerance of Cerianthus lloydii.

Orejas et al. (2012) describe the feeding ecology of Obelia dichotoma in an Arctic environment (Kongsfjorden, Svalbard) which experiences temperatures of 1-5°C (Beszczynska-Möller & Dye, 2013).  Palerud et al. (2004) also describe the presence of Obelia dichotoma, Halecium Halecinum and Nemertesia sp. in Svalbard.  This suggests that the characterizing hydroids are probably tolerant of the lowest temperatures they are likely to encounter in Britain and Ireland of ca 4°C (Beszczynska-Möller & Dye, 2013).  It should be noted that growth rates are reduced at low temperatures.  Berrill (1949) reported that for Obelia, stolons grew, under optimal nutritive conditions, at less than 1 mm in 24 hrs at 10-12°C, 10 mm in 24 hrs at 16-17°C, and as much as 15-20 mm in 24 hrs at 20°C.

Sensitivity assessment. All species assessed are present in northern/boreal habitats and are unlikely to be affected at the benchmark level.  Resistance has been assessed as ‘High’, and resilience as ‘High’.  Therefore, sensitivity has been assessed as ‘Not sensitive’ at the benchmark level.

High
Low
Medium
Medium
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High
High
High
High
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Not sensitive
Low
Medium
Medium
Help
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 evidence was found for osmoregulation by Cerianthus lloydiiCerianthus lloydii is recorded in biotopes with variable salinity regimes (18-40 psu) such as SS.SMx.CMx.ClloModHo but most records occur in full salinity. Studies on hydroids, in general, have found that prey capture rates may be affected by salinity and temperature (Gili & Hughes, 1995) although no evidence was found for Nemertesia antennina. However, due to the lack of evidence for the characterizing species within this biotope an assessment of ‘No evidence’ has been given. 

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
NR
NR
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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

No evidence was found for osmoregulation by Cerianthus lloydiiCerianthus lloydii is recorded in biotopes with variable salinity regimes (18-40 psu) such as SS.SMx.CMx.ClloModHo but most records occur in full salinity. Due to the lack of evidence for the characterizing species within this biotope an assessment of ‘No evidence’ has been given.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
NR
NR
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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

Evidence for the effect of changes in water flow on Cerianthus lloydii is unavailable.  This species is recorded from biotopes with a wide range of water flow regimes, from very weak to strong flow (Connor et al., 1997b).  Therefore, it is likely to have a high tolerance to changes in water flow regimes.

The characteristic hydroids are typically found in places of low to moderate water movement, although Hayward & Ryland (1995a) note that the abundant communities occur in narrow straits and headlands that may experience high levels of water flow. Hydroids can bend passively with water flow to reduce drag forces to prevent detachment and enhance feeding (Gili & Hughes, 1995). Hydroid growth form also varies to adapt to prevailing conditions, allowing species to occur in a variety of habitats (Gili & Hughes, 1995).  Flow rates are an important factor for feeding in hydroids, and prey capture rates are higher in areas of greater turbulence (Gili & Hughes, 1995).  The capture rate of zooplankton by hydroids is correlated with prey abundance (Gili & Hughes, 1995), thus prey availability can compensate for sub-optimal flow rates. Water movements are also important to hydroids to prevent siltation, which can cause death (Round et al., 1961). Tillin & Tyler-Walters (2014) suggest that the range of flow speeds experienced by biotopes in which hydroids are found indicate that a change (increase or decrease) in the maximum water flow experienced by mid-range populations for the short periods of peak spring tide flow would not have negative effects on this ecological group.

Sensitivity assessment. This biotope is recorded from moderately strong to very weak flow and wave exposed to very wave sheltered conditions from 5 m to 30 m depth.  The biotope probably experiences wave mediated flow in its more shallow examples while tidal flow is more important in its deeper examples.  The biotope probably would not occur in areas subject to both strong flow and wave action, nor in areas subject to very weak flow and shelter from wave action. Therefore, the biotope probably experiences a range of water flow and/or wave mediated flow between the extremes cited above.  Therefore, a change in the flow of 01.-0.2 m/s is probably not significant and a resistance and resilience are assessed as ‘High’ so that sensitivity is assessed as ‘Not sensitive’.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
Low
Low
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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

This biotope does not occur in the intertidal, and consequently an increase in emergence is considered 'Not relevant' to this biotope.

Not relevant (NR)
NR
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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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

No evidence for the effect of changes in wave exposure on Cerianthus lloydii was available.  However, it is recorded from extremely wave sheltered to wave exposed sites (Connor et al., 1997b). Jackson (2004) reported that Nemertesia ramosa was intolerant of high wave exposure and only found in sheltered areas.  Faucci & Boero (2000) recorded hydroid communities at two sites of different wave exposure and recorded the presence of Obelia dichotoma and Halecium spp. in both the exposed and sheltered sites, but only found Kirchenpaueria sp. in the sheltered site.

Sensitivity assessment.  This biotope is recorded from moderately strong to very weak flow and wave exposed to very wave sheltered conditions from 5 m to 30 m depth.  The biotope probably experiences wave mediated flow in its more shallow examples while tidal flow is more important in its deeper examples.  The biotope probably would not occur in areas suggest to both strong flow and wave action, nor in areas subject to very weak flow and shelter from wave action. Therefore, the biotope probably experiences a range of water flow and/or wave mediated flow between the extremes cited above. Storms may mobilise the surface of the substratum and may explain the sparse fauna.  Nevertheless, 3-5% change in significant wave height is unlikely to be significant within this biotope.  Therefore, resistance has been assessed as ‘High’, resilience as ‘High’ and the biotope is probably ‘Not sensitive’ at the benchmark level.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
Low
Low
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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.

Not Assessed (NA)
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NR
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Not assessed (NA)
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NR
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Not assessed (NA)
NR
NR
NR
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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.

Not Assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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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.

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

Radionuclide contamination

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

Evidence

No evidence.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
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NR
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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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NR
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Not assessed (NA)
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Not assessed (NA)
NR
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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

In general, respiration in most marine invertebrates does not appear to be significantly affected until extremely low concentrations are reached. For many benthic invertebrates, this concentration is about 2 ml/l (Herreid, 1980; Rosenberg et al., 1991; Diaz & Rosenberg, 1995).  Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l.

Hydroids mainly inhabit environments in which the oxygen concentration exceeds 5 ml/l (Gili & Hughes, 1995).  Diaz & Rosenberg (1995) noted that anemones include species that were reported to be particularly tolerant of hypoxia (e.g. Cerianthus sp and Epizoanthus erinaceus). A major hypoxic event due a pycnocline in the Gulf of Trieste resulted in a mass mortality of benthos between 12 and 26th September 1983 (Stachowitsch, 1992), during which the oxygen levels fell below 4.2 mg/l, became anoxic, and hydrogen sulphide and ammonia were released (Faganeli et al., 1985). Amongst the epifauna, the even hypoxia resistant polychaetes and bivalves died after 4-5 days and the only organism to survive after one week were the anemones Cerianthus sp and Epizoanthus erinaceus, the gastropods Aporrhais pespelecani and Trunculariopsis trunculus and the sphinuculid Sipunculus nudis (Stachowitsch, 1992).

Sensitivity assessment.  The above evidence suggests that Cerianthus lloydii would probably survive for a week at or below 2 mg O2/l while the hydroids would probably be reduced to just resting stages. Therefore, a resistance of 'Low' is recorded to represent the probable significant mortality of hydroids in the community. However, the hydroids would recover rapidly, so that resilience is likely to be 'High' and sensitivity 'Low'.

Low
High
High
Medium
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High
High
High
High
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Low
High
High
Medium
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Nutrient enrichment [Show more]

Nutrient enrichment

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

Evidence

No information was available on the effect of nutrient enrichment on Cerianthus lloydii. Witt et al. (2004) found that the hydroid Obelia sp. was more abundant in a sewage disposal area in the Weser estuary (Germany), which experienced sedimentation of 1 cm for more than 25 days.  It should be noted that another hydroid (Sertularia cupressina) was reduced in abundance when compared with unimpacted reference areas.  As suspension feeders, an increase in organic content at the benchmark is likely to be of benefit to the characterizing hydroids.  However, there is no direct evidence for the characterizing hydroid species Nemertesia anteninna.

Sensitivity assessment.  Little evidence was found on which to base an assessment.  However, the biotope is assessed as ‘Not sensitive' at the pressure benchmark of compliance with good status as defined by the WFD. 

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

Organic enrichment

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

Evidence

Borja et al. (2000) and Gittenberger & van Loon (2011) in the development of the AZTI Marine Biotic Index (AMBI) index to assess disturbance (including organic enrichment) both assigned Cerianthus lloydii to their Ecological Group I, ‘species very sensitive to organic enrichment and present under unpolluted conditions (initial state)’.  The basis for their assessment and relation to the pressure benchmark is not clear (Tillin & Tyler-Walters, 2014).

Witt et al. (2004) found that the hydroid Obelia spp. was more abundant in a sewage disposal area in the Weser estuary (Germany) which experienced sedimentation of 1 cm for more than 25 days.  It should be noted that another hydroid (Sertularia cupressina) was reduced in abundance when compared with unimpacted reference areas.  As suspension feeders, an increase in organic content at the benchmark is likely to be of benefit to the characterizing hydroids.

Sensitivity assessment.  At the pressure benchmark, which refers to enrichment rather than gross organic pollution, this biotope is considered to have a 'Low' resistance and hence, 'Medium' resilience. Therefore, sensitivity is assessed as 'Medium'.

Low
High
Medium
Medium
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Medium
Low
Medium
Medium
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Medium
Low
Medium
Medium
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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
High
High
High
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Very Low
High
High
High
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High
High
High
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

If rock was replaced with sediment, this would represent a fundamental change to the physical character of the biotope and the species would be unlikely to recover. The biotope would be lost.

Sensitivity assessment.  The resistance to this change is ‘None’, and the resilience is assessed as ‘Very low’ due to the permanent nature of a change in the substratum.  The biotope is assessed to have a ‘High’ sensitivity to this pressure at the benchmark.

None
High
High
High
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Very Low
High
High
High
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High
High
High
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

Cerianthus lloydii is found in a very wide range of substrata (Tillin & Tyler-Walters, 2014), but only dominates the fauna in the mixed substrata biotope described in this biotope  A change in Folk class from mixed to coarse or sandy mud substrata would result in loss of the biotope, even though population of Cerianthus lloydii could remain. Nemertesia antennina and other hydroids are only found attached to large pebbles and cobbles within SS.SMx.CMx.ClloMx.Nem. A reduction in the presence of cobbles and pebbles due to a change in sediment type would also reduce the abundance of the characteristic hydroids.

Sensitivity assessment.  A change in the substratum by one Folk class would result in the loss of the biotope. Therefore, a resistance of ‘None’ is recorded.  As resilience is 'Very low' (the pressure is a permanent change), sensitivity is, therefore, 'High'

None
Low
NR
NR
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Very Low
High
High
High
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High
Low
Low
Low
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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

Resistance is assessed as ‘None’ based on expert judgment but supported by the literature relating to the position of these species on or within the seabed.  At the pressure benchmark, the exposed sediments are considered suitable for recolonization almost immediately following extraction.  Recovery will be mediated by the scale of the disturbance and the suitability of the sedimentary habitat.  Recovery is most likely to occur via larval recolonization.  Resilience is probably ‘Low’, so that sensitivity is assessed as ‘High’.

None
Low
NR
NR
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Low
Medium
Low
Low
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High
Low
Low
Low
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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

No direct evidence was found to assess the sensitivity Cerianthus lloydii to surface abrasion.  The burrowing life habit of the species specifically assessed would confer some protection from surface disturbance although individuals would be more exposed when close to the surface feeding. Cerianthus lloydii inhabits a soft tube, which can be up to 40 cm long and is permanently buried. The anemone can move freely within the tube and can retract swiftly if required (Tillin & Tyler-Walters, 2014).

The available evidence indicates that hydroids can be entangled and removed by abrasion.  Drop down video surveys of Scottish reefs exposed to trawling showed that visual evidence of damage to bryozoans and hydroids on rock surfaces was generally limited and restricted to scrape scars on boulders (Boulcott & Howell, 2011).  The study showed that damage is incremental with damage increasing with the frequency of trawls rather than a blanket effect occurring on the pass of the first trawls.

Re-sampling of grounds that were historically studied (from the 1930s) indicates that some species have increased in areas subject to scallop fishing (Bradshaw et al., 2002).  This study also found (unquantified) increase in abundance of tough stemmed hydroids including Nemertesia spp.; its morphology may have prevented excessive damage. Bradshaw et al. (2002) suggested that as well as having high resistance to abrasion pressures, Nemertesia spp. have benthic larvae that could rapidly colonize disturbed areas with newly exposed substrata close to the adult.  Hydroids may also recover rapidly as the surface covering of hydrorhizae may remain largely intact, from which new uprights are likely to grow. In addition, the resultant fragments of colonies may be able to develop into new colonies.

Hydroid colonies were still present in the heavily fished area, albeit at lower densities than in the closed area. This may largely be because the Isle of Man scallop fishery is closed from 1st June to 31st October (Andrews et al., 2011), so at the time the samples were taken for the study in question, the seabed had been undredged for at least 3.5 months. The summer period is also the peak growing/breeding season for many marine species. (Bradshaw et al., 2003)

Sensitivity assessment.  Abrasion at the surface only is considered likely to damage and remove epiphytic species.  Cerianthus lloydii has the ability to retract into its tube.  However, there is the possibility of the tube being damaged, which could affect the health of the organism.  The resistance of the biotope is assessed as ‘Medium’, although the significance of the impact for the bed will depend on the spatial scale of the pressure footprint.  Resilience is assessed as ‘Medium’ (2-10 years), and sensitivity is assessed as ‘Medium’.

Medium
Low
Medium
Medium
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Medium
Low
Medium
Medium
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Medium
Low
Medium
Medium
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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

Penetration and or disturbance of the substratum would result in similar results as abrasion or removal of this biotope.  Damage to Cerianthus lloydii would be greater within this pressure, as their ability to retract within their tubes would be limited.

Sensitivity assessment.  The resistance of the biotope is assessed as ‘Low’, although the significance of the impact for the bed will depend on the spatial scale of the pressure footprint.  Resilience is assessed as ‘Medium’, and sensitivity is assessed as ‘Medium’.

Low
Low
Medium
Medium
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Medium
Low
Medium
Medium
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Medium
Low
Medium
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

An increase in suspended sediment may have a deleterious effect on the suspension feeding community.  It is likely to clog their feeding apparatus to some degree, resulting in a reduced ingestion over the benchmark period and, subsequently, a decrease in growth rate (Jackson, 2004).  As the hydroids capture small prey in suspension (Gili & Hughes, 1995), a reduction in feeding efficiency could potentially lead to a reduction in overall biomass.

No evidence on the effect of a change in turbidity on Cerianthus lloydii could be found. Nemertesia ramosa is a passive suspension feeder, extracting seston from the water column. Increased siltation may clog up the feeding apparatus, requiring energetic expenditure to clear.  Recovery is likely to take only a few days. (Jackson, 2004).  A decrease in suspended sediment is likely to benefit the community associated with this biotope. The suspension feeders may be able to feed more efficiently due to a reduction in time and energy spent cleaning feeding apparatus. Over the course of the benchmark, the hydroids may increase in abundance.

Sensitivity assessment.  No directly relevant evidence was found to assess the effect of pressure.  Resistance to this pressure is assessed as 'High' as an increase in turbidity may influence feeding and growth rates but not result in mortality of adults.  Resilience is assessed as 'High' (by default) and the biotope is assessed as 'Not sensitive' to changes in turbidity at the benchmark level.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
Low
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

In normal accretion, Cerianthus lloydii keeps pace with the accretion and, as a result, develops burrows much larger than the animal itself (Schäfer, 1972; Bromley, 2012). Schäfer (1972) reported that an increase in depositional rate led to an avoidance behaviour in Cerianthus lloydii.  The organism ceases tube building activity and instead the animal bunches its tentacles and intrudes its way up to the new surface, where it establishes a new burrow. However, no information on the depth of material through which it can burrow was given.

In general, it appears that hydroids are sensitive to silting (Boero, 1984; Gili & Hughes, 1995) and the decline of beds in the Wadden Sea have been linked to environmental changes including siltation.  Round et al., 1961 reported that the hydroid Sertularia (now Amphisbetia) operculata died when covered with a layer of silt after being transplanted to sheltered conditions.  Boero (1984) suggested that deepwater hydroid species develop upright, thin colonies that accumulate little sediment, while species in turbulent water movement were adequately cleaned of silt by water movement.  Hughes (1977) found that maturing hydroids that had been smothered with detritus and silt lost most of the hydrocladia and hydranths. After one month, the hydroids were seen to have recovered but although neither the growth rate nor the reproductive potential appeared to have been affected, the viability of the planulae may have been affected.  Nemertesia ramosa is an upright hydroid with a height of up to 15 cm. The colony structure is fairly tough and flexible. Smothering with 5 cm of sediment may cover over some individuals; others may just have the lower section of the main stem covered (Hayward & Ryland, 1994).

Sensitivity assessment. Cerianthus lloydii will actively burrow up through sediment that has smothered the entrance to its burrow.  The thickness of sediment through which Cerianthus lloydii is able to burrow is not known.  Smothering by 5 cm of sediment is likely to cause some mortality of Cerianthus lloydii.  It may be possible for fully grown adults to burrow through the sediment, however, the confidence in this assessment is low.  This pressure will also influence the hydroid species within SS.SMx.CMx.ClloMx.Nem.  Given the information available, the resistance to this pressure is considered to be ‘Medium’, as is the resilience, and sensitivity is assessed as ‘Medium’ at the benchmark.

Medium
Medium
Low
Low
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Medium
Low
Medium
Medium
Help
Medium
Low
Low
Low
Help
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

In normal accretion, Cerianthus lloydii keeps pace with the accretion and, as a result, develops burrows much larger than the animal itself (Schäfer, 1972; Bromley, 2012). Schäfer (1972) reported that an increase in depositional rate led to an avoidance behaviour in Cerianthus lloydii.  The organism ceases tube building activity and instead the animal bunches its tentacles and intrudes its way up to the new surface, where it establishes a new burrow. However, no information on the depth of material through which it can burrow was given.

In general, it appears that hydroids are sensitive to silting (Boero, 1984; Gili & Hughes, 1995) and the decline of beds in the Wadden Sea have been linked to environmental changes including siltation.  Round et al. (1961) reported that the hydroid Sertularia (now Amphisbetia) operculata died when covered with a layer of silt after being transplanted to sheltered conditions.  Boero (1984) suggested that deepwater hydroid species develop upright, thin colonies that accumulate little sediment, while species in turbulent water movement were adequately cleaned of silt by water movement.  Hughes (1977) found that maturing hydroids that had been smothered with detritus and silt lost most of the hydrocladia and hydranths. After one month, the hydroids were seen to have recovered but although neither the growth rate nor the reproductive potential appeared to have been affected, the viability of the planulae may have been affected.  Nemertesia ramosa is an upright hydroid with a height of up to 15 cm and Nemertesia antennina grows up to 25 cm (Hayward & Ryland, 1994). The colony structure is fairly tough and flexible. Smothering with 30 cm of sediment will completely cover all individuals.

Sensitivity assessment. Cerianthus lloydii will actively burrow up through sediment that has smothered the entrance to its burrow.  The thickness of sediment through which Cerianthus lloydii is able to burrow is not known.  However, at a maximum body length of 15 cm, a deposit of 30 cm is a considerable amount of sediment to burrow through.  The level of energy expenditure needed to burrow through this amount of sediment may be too much for some individuals, and there will be a higher change of asphyxia due to the amount of time the organisms are buried. For these reasons smothering by 30 cm of sediment is likely to cause mortality of a large proportion of Cerianthus lloydii.  At this pressure benchmark, the hydroid species within SS.SMx.CMx.ClloMx.Nem will all be totally smothered, which will result in their death.  Given the information available, the resistance to this pressure is considered to be ‘Low’, the resilience is probably 'Medium', and sensitivity is assessed as ‘Medium’ at the benchmark.

Low
Low
NR
NR
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Medium
Low
Medium
Medium
Help
Medium
Low
Low
Low
Help
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)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
Help
Not assessed (NA)
NR
NR
NR
Help
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)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
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

Species characterizing this habitat do not have hearing perception but vibrations may cause a response. However, noise, as defined by the pressure, is probably 'Not relevant'.

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

Introduction of light or shading

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

Evidence

No evidence.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
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

Not relevant – this pressure is considered applicable to mobile species, e.g. fish and marine mammals rather than seabed habitats. Physical and hydrographic barriers may limit propagule dispersal.  But propagule dispersal is not considered under the pressure definition and benchmark.

Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
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)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
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)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help

Biological Pressures

Use [show more] / [show less] to open/close text displayed

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

Habitat restoration projects may translocate stock to re-populate areas of suitable habitat (Elsäßer et al., 2013).  No evidence was found for detrimental effects arising from this practice in the habitat, although there is potential for the movement of pathogens and non-indigenous, invasive species.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
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 (Stiger-Pouvreau & Thouzeau, 2015, Blanchard, 2009). 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. 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). 

King scallop (Pecten maximus) and Queen scallop (Aequipecten opercularis) in the Bay of Brest, have been reported to decrease in the presence of Crepidula, largely due to silting and biodeposition that changes the habitat (Stiger Pouvreau & Thouzeau, 2015; Thouzeau et al., 2000). The scallop post larvae are unable to settle and survive on muddy Crepidula substrata. Crepidula could potentially be the main competitor for Pecten maximus, especially creating competition for space (Menesguen & Gregoris, 2018; Ragueneau et al., 2018). However, no direct competition for food was observed between Crepidula and the scallops (Thouzeau et al., 2000, Chauvaud et al. 2000) and scallop shell growth rates did not decrease with increasing Crepidula populations. Therefore, although Crepidula populations will likely impact scallop post-larvae settlement, it does not affect shell growth rates or adult survivorship (Thouzeau et al., 2000). Models show that competition for space between the species does not impact the abundance of Crepidula, but does lower the abundance of Pecten sp. (Menesguen & Gregoris, 2018). 

Sensitivity assessment. The sediments characterizing this biotope are likely to be too mobile and unsuitable for most of the invasive non-indigenous species currently recorded in the UK. However, the above evidence suggests that Crepidula could colonize mixed sediment habitats in the subtidal, typical of this biotope, due to the presence of gravel or any other hard substrata that can be used for larvae settlement (Tillin et al., 2020). 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 is an exposed to very sheltered habitat, so storms may mobilise the sediment (JNCC, 2022), which may also mitigate or prevent colonization by Crepidula at high densities, although it has been recorded from areas of strong tidal streams (Hinz et al., 2011). Therefore, the habitat may be more suitable for Crepidula in wave sheltered areas of the biotope and where water movement is mediated by tidal flow rather than wave action, e.g., the deeper examples of the biotope. 

Therefore, resistance is assessed as 'Medium' in examples where wave action is high and subject to storms but 'Low' in wave sheltered areas dominated by tidal flow. Resilience is assessed as 'Very low' as it would require the removal of Crepidula, probably by artificial means. Hence, sensitivity is assessed as 'High' 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.

Low
Low
NR
NR
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Very Low
High
High
High
Help
High
Low
NR
NR
Help
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 available on the effect of microbial pathogens on Cerianthus lloydii.  Hydroids exhibit astonishing regeneration and rapid recovery from injury (Sparks, 1972) and the only inflammatory response is active phagocytosis (Tokin & Yaricheva, 1959; 1961, as cited in Sparks, 1972).  No record of diseases in the characterizing hydroids could be found.

Sensitivity assessment.  There was insufficient information to assess the effect of this pressure on the biotope.  Therefore, an assessment of ‘No evidence’ has been given. 

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
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

Sensitivity assessment.  None of the characterizing species within this biotope are currently directly targeted in the UK and hence this pressure is considered to be ‘Not relevant’.

Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
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

Direct, physical impacts from harvesting are assessed through the abrasion and penetration of the seabed pressures.  The characterizing species within this biotope could easily be incidentally removed from this biotope as by-catch when other species are being targeted.  The loss of these species and other associated species would decrease species richness and negatively impact on the ecosystem function.

Sensitivity assessment. Removal of a large percentage of the characterizing species would alter the character of the biotope.  The resistance to removal is ‘Low’ due to the easy accessibility of the biotopes location and the inability of these species to evade collection. The resilience is ‘Medium’ with recovery only being able to begin when the harvesting pressure is removed altogether. This gives an overall sensitivity score of ‘Medium’.

Medium
Low
Medium
Medium
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Medium
Low
Medium
Medium
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Medium
Low
Medium
Medium
Help

Bibliography

  1. Andrews, J.W., Brand, A.R. & Holt, T.J., 2011. Isle of Man Queen Scallop Trawl and Dredge Fishery. MSC assessment report. pp. 203.

  2. Attrill, M.J., Wright, J. & Edwards, M., 2007. Climate-related increases in jellyfish frequency suggest a more gelatinous future for the North Sea. Limnology and Oceanography, 52 (1), 480-485. DOI https://doi.org/10.4319/lo.2007.52.1.0480

  3. Berghahn, R. & Offermann, U. 1999. Laboratory investigations on larval development, motility and settlement of white weed (Sertularia cupressina L.) - in view of its assumed decrease in the Wadden Sea. Hydrobiogia, 392(2), 233–239.

  4. Berrill, N.J., 1948. A new method of reproduction in Obelia. Biological Bulletin, 95, 94-99.

  5. Berrill, N.J., 1949. The polymorphic transformation of Obelia. Quarterly Journal of Microscopical Science, 90, 235-264.

  6. Beszczynska-Möller, A., & Dye, S.R., 2013. ICES Report on Ocean Climate 2012. In ICES Cooperative Research Report, vol. 321 pp. 73.

  7. 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

  8. 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/

  9. Boco, S.R., Pitt, K.A. & Melvin, S.D., 2019. Extreme, but not moderate climate scenarios, impart sublethal effects on polyps of the Irukandji jellyfish, Carukia barnesi. Science of The Total Environment, 685, 471-479. DOI https://doi.org/10.1016/j.scitotenv.2019.05.451

  10. Boero, F., 1984. The ecology of marine hydroids and effects of environmental factors: a review. Marine Ecology, 5, 93-118.

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. Boulcott, P. & Howell, T.R.W., 2011. The impact of scallop dredging on rocky-reef substrata. Fisheries Research (Amsterdam), 110 (3), 415-420.

  17. Bradshaw, C., Collins, P. & Brand, A., 2003. To what extent does upright sessile epifauna affect benthic biodiversity and community composition? Marine Biology, 143 (4), 783-791.

  18. Bradshaw, C., Veale, L.O., Hill, A.S. & Brand, A.R., 2002. The role of scallop-dredge disturbance in long-term changes in Irish Sea benthic communities: a re-analysis of an historical dataset. Journal of Sea Research, 47, 161-184. DOI https://doi.org/10.1016/S1385-1101(02)00096-5

  19. Bromley, R.G., 2012. Trace Fossils: Biology, Taxonomy and Applications: Routledge.

  20. Cantero, Á.L.P., Carrascosa, A.M.G. & Vervoort, W., 2002. The benthic hydroid fauna of the Chafarinas Islands (Alborán Sea, western Mediterranean): Nationaal Natuurhistorisch Museum.

  21. Cazenave, A. & Nerem, R.S., 2004. Present-day sea-level change: Observations and causes. Reviews of Geophysics, 42 (3). DOI https://doi.org/10.1029/2003rg000139

  22. Chauvaud, L., Jean, F., Ragueneau, O. & Thouzeau, G., 2000. Long-term variation of the Bay of Brest ecosystem: benthic-pelagic coupling revisited. Marine Ecology Progress Series, 200, 35-48. DOI https://doi.org/10.3354/meps200035

  23. Church, J.A. & White, N.J., 2006. A 20th century acceleration in global sea-level rise. Geophysical Research Letters, 33 (1). DOI https://doi.org/10.1029/2005gl024826

  24. Church, J.A., White, N.J., Coleman, R., Lambeck, K. & Mitrovica, J.X., 2004. Estimates of the Regional Distribution of Sea Level Rise over the 1950–2000 Period. Journal of Climate, 17 (13), 2609-2625.

  25. Cole, S., Codling, I.D., Parr, W. & Zabel, T., 1999. Guidelines for managing water quality impacts within UK European Marine sites. Natura 2000 report prepared for the UK Marine SACs Project. 441 pp., Swindon: Water Research Council on behalf of EN, SNH, CCW, JNCC, SAMS and EHS. [UK Marine SACs Project.]. Available from: http://ukmpa.marinebiodiversity.org/uk_sacs/pdfs/water_quality.pdf

  26. 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/

  27. Connor, D.W., Brazier, D.P., Hill, T.O., & Northen, K.O., 1997b. Marine biotope classification for Britain and Ireland. Vol. 1. Littoral biotopes. Joint Nature Conservation Committee, Peterborough, JNCC Report no. 229, Version 97.06., Joint Nature Conservation Committee, Peterborough, JNCC Report No. 230, Version 97.06.

  28. Cornelius, P.F.S., 1992. Medusa loss in leptolid Hydrozoa (Cnidaria), hydroid rafting, and abbreviated life-cycles among their remote island faunae: an interim review.

  29. Cornelius, P.F.S., 1995a. North-west European thecate hydroids and their medusae. Part 1. Introduction, Laodiceidae to Haleciidae. Shrewsbury: Field Studies Council. [Synopses of the British Fauna no. 50]

  30. Danovaro, R., Corinaldesi, C., Dell'Anno, A. & Snelgrove, P.V.R., 2017. The deep-sea under global change. Current biology: CB, 27 (11), R461-R465. DOI https://doi.org/10.1016/j.cub.2017.02.046

  31. Davies, J.S., Howell, K.L., Stewart, H.A., Guinan, J. & Golding, N., 2014. Defining biological assemblages (biotopes) of conservation interest in the submarine canyons of the South West Approaches (offshore United Kingdom) for use in marine habitat mapping. Deep Sea Research Part II: Topical Studies in Oceanography, 104, 208-229
  32. De Barros Marangoni, L.F., Calderon, E.N., Marques, J.A., Duarte, G.A.S., Pereira, C.M., e Castro, C.B. & Bianchini, A.J.C.R., 2017. Effects of CO2-driven acidification of seawater on the calcification process in the calcareous hydrozoan Millepora alcicornis (Linnaeus, 1758). 36 (4), 1133-1141. DOI https://doi.org/10.1007/s00338-017-1605-6

  33. De Kluijver, M., Ingalsuo, S., Van Nieuwenhuijzen, A. and van Zanten, H.V., 2024. Macrobenthos of the North Sea. Vol. II – Anthozoa. [Online] Available from https://ns-anthozoa.linnaeus.naturalis.nl/linnaeus_ng/app/views/introduction/topic.php?id=3402

  34. 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

  35. 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.

  36. 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

  37. Diaz, R.J. & Rosenberg, R., 1995. Marine benthic hypoxia: a review of its ecological effects and the behavioural responses of benthic macrofauna. Oceanography and Marine Biology: an Annual Review, 33, 245-303.

  38. Elsäßer, B., Fariñas-Franco, J.M., Wilson, C.D., Kregting, L. & Roberts, D., 2013. Identifying optimal sites for natural recovery and restoration of impacted biogenic habitats in a special area of conservation using hydrodynamic and habitat suitability modelling. Journal of Sea Research, 77, 11-21.

  39. Fabry, V.J., Seibel, B.A., Feely, R.A. & Orr, J.C., 2008. Impacts of ocean acidification on marine fauna and ecosystem processes. ICES Journal of Marine Science, 65 (3), 414-432. DOI https://doi.org/10.1093/icesjms/fsn048

  40. Faganeli, J., Avčin, A., Fanuko, N., Malej, A., Turk, V., Tušnik, P., Vrišer, B. & Vukovič, A., 1985. Bottom layer anoxia in the central part of the Gulf of Trieste in the late summer of 1983. Marine Pollution Bulletin, 16(2), 75-78.

  41. 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

  42. Gili, J-M. & Hughes, R.G., 1995. The ecology of marine benthic hydroids. Oceanography and Marine Biology: an Annual Review, 33, 351-426.

  43. 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

  44. 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

  45. Gutierre, S.M.M., 2012. pH tolerance of the biofouling invasive hydrozoan Cordylophora caspia. Hydrobiologia, 679 (1), 91-95. DOI https://doi.org/10.1007/s10750-011-0855-5

  46. Hatcher, A.M., 1998. Epibenthic colonization patterns on slabs of stabilised coal-waste in Poole Bay, UK. Hydrobiologia, 367, 153-162.

  47. Hayward, P.J. & Ryland, J.S. 1994. The marine fauna of the British Isles and north-west Europe. Volume 1. Introduction and Protozoans to Arthropods. Oxford: Clarendon Press.

  48. Hayward, P.J. & Ryland, J.S. (ed.), 1995. The marine fauna of the British Isles and north-west Europe. Volume 2. Molluscs to Chordates. Oxford Science Publications. Oxford: Clarendon Press.

  49. Helmer, L., Farrell, P., Hendy, I., Harding, S., Robertson, M. & Preston, J., 2019. Active management is required to turn the tide for depleted Ostrea edulis stocks from the effects of overfishing, disease and invasive species. Peerj, 7 (2). DOI https://doi.org/10.7717/peerj.6431

  50. Herreid, C.F., 1980. Hypoxia in invertebrates. Comparative Biochemistry and Physiology Part A: Physiology, 67 (3), 311-320. DOI https://doi.org/10.1016/S0300-9629(80)80002-8

  51. 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

  52. Hughes, D.J., 1998a. Sea pens & burrowing megafauna (volume III). An overview of dynamics and sensitivity characteristics for conservation management of marine SACs. Natura 2000 report prepared for Scottish Association of Marine Science (SAMS) for the UK Marine SACs Project., Scottish Association for Marine Science. (UK Marine SACs Project). Available from: http://ukmpa.marinebiodiversity.org/uk_sacs/pdfs/seapens.pdf

  53. Hughes, R.G., 1977. Aspects of the biology and life-history of Nemertesia antennina (L.) (Hydrozoa: Plumulariidae). Journal of the Marine Biological Association of the United Kingdom, 57, 641-657.

  54. IPCC (Intergovernmental Panel on Climate Change), 2019. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. Intergovernmental Panel on Climate Change, Geneva, Switzerland, 1170 pp. Available from https://www.ipcc.ch/srocc/home/

  55. Jackson, A. 2004. Nemertesia ramosa, A hydroid. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 02/03/16] Available from: http://www.marlin.ac.uk/species/detail/1318

  56. Jacobson, M.Z., 2005. Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry. Journal of Geophysical Research: Atmospheres, 110 (D7). DOI https://doi.org/10.1029/2004JD005220

  57. Jensen, A.C., Collins, K.J., Lockwood, A.P.M., Mallinson, J.J. & Turnpenny, W.H., 1994. Colonization and fishery potential of a coal-ash artificial reef, Poole Bay, United Kingdom. Bulletin of Marine Science, 55, 1263-1276.

  58. 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/

  59. 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/

  60. Johnson, D., Adelaide Ferreira, M. & Kenchington, E., 2018. Climate change is likely to severely limit the effectiveness of deep-sea ABMTs in the North Atlantic. Marine Policy, 87, 111-122. DOI https://doi.org/10.1016/j.marpol.2017.09.034

  61. Kosevich, I.A. & Marfenin, N.N., 1986. Colonial morphology of the hydroid Obelia longissima (Pallas, 1766) (Campanulariidae). Vestnik Moskovskogo Universiteta Seriya Biologiya, 3, 44-52.

  62. Li, Y., Zhang, H., Tang, C., Zou, T. & Jiang, D., 2016. Influence of Rising Sea Level on Tidal Dynamics in the Bohai Sea. 74 (SI), 22-31. DOI https://doi.org/10.2112/si74-003.1

  63. Lowe, J., Bernie, D., Bett, P., Bricheno, L., Brown, S., Calvert, D., Clark, R.T., Eagle, K.E., Edwards, T., Fosser, G., Fung, F., Gohar, L., Good, P., Gregory, J., Harris, G.R., Howard, T., Kaye, N., Kendon, E.J., Krijnen, J., Maisey, P., McDonald, R.E., McInnes, R.N., McSweeney, C.F., Mitchell, J.F.B., Murphy, J.M., Palmer, M., Roberts, C., Rostron, J.W., Sexton, D.M.H., Thornton, H.E., Tinker, J., Tucker, S., Yamazaki, K. & Belcher, S., 2018. UKCP18 Science Overview Report. Meterological Office, Hadley Centre, Exeter, UK, 73 pp. Available from https://www.metoffice.gov.uk/research/approach/collaboration/ukcp/index

  64. 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

  65. Medel, M., García, F. & Vervoort, W., 1998. The family Haleciidae (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas. Zoologische Mededeelingen, 72, 29-50.

  66. Menesguen, A. & Gregoris, T., 2018. Modelling benthic invasion by the colonial gastropod Crepidula fornicata and its competition with the bivalve Pecten maximus. 1. A new 0D model for population dynamics of colony-forming species. Ecological Modelling, 368, 277-287. DOI https://doi.org/10.1016/j.ecolmodel.2017.12.005

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

  68. Mossman, H.L., Grant, A., Lawrence, P.J. & Davy, A.J., 2015. Biodiversity climate change impacts report card technical paper 10. Implications of climate change for coastal and inter-tidal habitats of the UK. Biodiversity climate change impacts, Living With Environmental Change, NERC, UKRI,  26 pp. Available from https://nerc.ukri.org/research/partnerships/ride/lwec/report-cards/biodiversity-source10/

  69. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-07-21

  70. Orejas, C., Rossi, S., Peralba, À., García, E., Gili, J.M. & Lippert, H., 2012. Feeding ecology and trophic impact of the hydroid Obelia dichotoma in the Kongsfjorden (Spitsbergen, Arctic). Polar biology, 36 (1), 61-72.

  71. Palerud, R., Gulliksen, B., Brattegard, T., Sneli, J.-A. & Vader, W., 2004. The marine macro-organisms in Svalbard waters. A catalogue of the terrestrial and marine animals of Svalbard. Norsk Polarinstitutt Skrifter, 201, 5-56.

  72. Palmer, M., Howard, T., Tinker, J., Lowe, J., Bricheno, L., Calvert, D., Edwards, T., Gregory, J., Harris, G., Krijnen, J., Pickering, M., Roberts, C. & Wolf, J., 2018. UKCP18 Marine Report. Met Office, The Hadley Centre, Exeter, UK, 133 pp. Available from https://www.metoffice.gov.uk/pub/data/weather/uk/ukcp18/science-reports/UKCP18-Marine-report.pdf

  73. Pickering, M.D., Wells, N.C., Horsburgh, K.J. & Green, J.A.M., 2012. The impact of future sea-level rise on the European Shelf tides. Continental Shelf Research, 35, 1-15. DOI https://doi.org/10.1016/j.csr.2011.11.011

  74. 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

  75. 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

  76. Ragueneau, O., Raimonet, M., Maze, C., Coston-Guarini, J., Chauvaud, L., Danto, A., Grall, J., Jean, F., Paulet, Y. M. & Thouzeau, G., 2018. The Impossible Sustainability of the Bay of Brest? Fifty Years of Ecosystem Changes, Interdisciplinary Knowledge Construction and Key Questions at the Science-Policy-Community Interface. Frontiers in Marine Science, 5. DOI https://doi.org/10.3389/fmars.2018.00124

  77. Rosenberg, R., Hellman, B. & Johansson, B., 1991. Hypoxic tolerance of marine benthic fauna. Marine Ecology Progress Series, 79, 127-131. DOI https://dx.doi.org/10.3354/meps079127

  78. Round, F.E., Sloane, J.F., Ebling, F.J. & Kitching, J.A., 1961. The ecology of Lough Ine. X. The hydroid Sertularia operculata (L.) and its associated flora and fauna: effects of transference to sheltered water. Journal of Ecology, 49, 617-629.

  79. Schäfer, W., 1972. Ecology and palaeoecology of marine environments, 568 pp. Edinburgh: Oliver & Boyd.

  80. Sommer, C., 1992. Larval biology and dispersal of Eudendrium racemosum (Hydrozoa, Eudendriidae). Scientia Marina, 56, 205-211. [Proceedings of 2nd International Workshop of the Hydrozoan Society, Spain, September 1991. Aspects of hydrozoan biology (ed. J. Bouillon, F. Cicognia, J.M. Gili & R.G. Hughes).]

  81. Sparks, A., 1972. Invertebrate Pathology Noncommunicable diseases: Elsevier.

  82. Stachowitsch, M., 1992b. Benthic communities: eutrophication's memory mode. In The Response of marine transitional systems to human impact: problems and perspectives for restoration  Proceedings of an International Conferencee, Bologna, Italy, 21-24 March, 1990, (ed. R.A. Vollenweider, R. Marchetti, & R. Viviani), pp.1017-1028. Amsterdam: Elsevier.

  83. Stepanjants, S.D. & Chernyshev, A.V., 2015. Deep-sea epibiotic hydroids from the abyssal plain adjacent to the Kuril–Kamchatka Trench with description of Garveia belyaevi sp. nov. (Hydrozoa, Bougainvilliidae). Deep Sea Research Part II: Topical Studies in Oceanography, 111, 44-48. DOI https://doi.org/10.1016/j.dsr2.2014.07.015

  84. 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

  85. Thouzeau, Gérard, Chauvaud, Laurent, Grall, Jacques & Guérin, Laurent, 2000. Rôle des interactions biotiques sur le devenir du pré-recrutement et la croissance de Pecten maximus (L.) en rade de Brest. Comptes Rendus de l#&39;Académie des Sciences - Series III - Sciences de la Vie, 323 (9), 815-825. DOI https://doi.org/10.1016/S0764-4469(00)01232-4

  86. Thouzeau, G., Chavaud, L., Grall, J. & Guerin, L., 2000. Do biotic interactions control pre-recruitment and growth of Pecten maximus (L.) in the Bay of Brest ? Comptes rendus - acadamies des sciences, Paris, 323, 815-825.

  87. Tillin, H. & Tyler-Walters, H., 2014b. Assessing the sensitivity of subtidal sedimentary habitats to pressures associated with marine activities. Phase 2 Report – Literature review and sensitivity assessments for ecological groups for circalittoral and offshore Level 5 biotopes. JNCC Report No. 512B,  260 pp. Available from: www.marlin.ac.uk/publications

  88. 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

  89. Witt, J., Schroeder, A., Knust, R. & Arntz, W.E., 2004. The impact of harbour sludge disposal on benthic macrofauna communities in the Weser estuary. Helgoland Marine Research, 58 (2), 117-128.

Citation

This review can be cited as:

Perry, F., & Watson, A., 2024. Cerianthus lloydii and other burrowing anemones in circalittoral muddy mixed sediment. 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 21-07-2024]. Available from: https://marlin.ac.uk/habitat/detail/1091

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