Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

30-11-2001
Researched byDr Keith Hiscock Refereed byThis information is not refereed.
EUNIS CodeA5.132 EUNIS NameHalcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

Summary

UK and Ireland classification

EUNIS 2008A5.132Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel
EUNIS 2006A5.132Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel
JNCC 2004SS.SCS.ICS.HchrEdwHalcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel
1997 BiotopeSS.IGS.FaG.HalEdwHalcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

Description

Periodically (seasonally?) disturbed sublittoral stone gravel with small pebbles characterized by the presence of the anemones Halcampa chrysanthellum and Edwardsia timida. This biotope may also be contain opportunistic red seaweeds such as Palmaria palmata. Associated species are often typical of a hydroid/bryozoan turf but with infauna such as Sabella pavonina and Megalomma vesiculosum. It should be noted that this habitat may show considerable variation in community composition. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Recorded distribution in Britain and Ireland

Recorded from a very small number of locations in western Scotland.

Depth range

5-10 m, 10-20 m

Additional information

-

Listed By

Further information sources

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JNCC

Habitat review

Ecology

Ecological and functional relationships

Most species in this biotope are not interacting with each other except in competition for space although the characteristic species are so widely separated, there is unlikely to be significant competition. It is expected that there will be grazers present - small prosobranchs and chitons especially although the biotopes classification gives no indication. There is no information available on the infauna of the biotope.

Seasonal and longer term change

The biotope character (Connor et al., 1997a) suggests that there might be periodic (seasonal?) disturbance of the gravel and pebbles. Such disturbance might occur during spring tides when currents will increase or during storms when wave action may be important. It also seems likely that there will be seasonal occurrence of algae attached to pebbles.

Habitat structure and complexity

The habitat will attract both infauna and epibiota although epibiota will be restricted to encrusting and foliose species.

Productivity

Productivity will be mainly secondary although there could be quite high rates of primary production on pebbles most likely grazed rapidly.

Recruitment processes

Recruitment will predominantly be from the plankton including for the mobile species such as prosobranchs and chitons likely to be present. It is likely that some echinoderms such as starfish will migrate from other areas.

Time for community to reach maturity

The community probably includes several slow-growing and long-lived species that do not recruit regularly. This is thought to be the case especially for burrowing sea anemones.

Additional information

No other information.

Preferences & Distribution

Recorded distribution in Britain and IrelandRecorded from a very small number of locations in western Scotland.

Habitat preferences

Depth Range 5-10 m, 10-20 m
Water clarity preferences
Limiting Nutrients No information found
Salinity Full (30-40 psu)
Physiographic Open coast
Biological Zone Infralittoral
Substratum Gravel / shingle, Pebbles
Tidal Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Weak < 1 knot (<0.5 m/sec.)
Wave Moderately exposed, Sheltered
Other preferences

Additional Information

Species composition

Species found especially in this biotope

Rare or scarce species associated with this biotope

Additional information

Sensitivity reviewHow is sensitivity assessed?

Explanation

There is very little information available to indicate likely sensitivity of characteristic or other species of community importance in the biotope. Assessment of sensitivity and recoverability relies on a general knowledge of biology of biotopes where the surface layer of biota is likely to be disturbed occasionally but infauna species are likely to be long-lived and have stable populations.

Species indicative of sensitivity

Community ImportanceSpecies nameCommon Name
Important characterizingEdwardsia timidaA sea anemone
Important characterizingHalcampa chrysanthellumA sea anemone

Physical Pressures

 IntoleranceRecoverabilitySensitivitySpecies RichnessEvidence/Confidence
High Low High Major decline Very low
Removal of the substratum would result in loss of the biotope, therefore intolerance is recorded as high. The biotope is rarely recorded suggesting that prospects for recovery from nearby populations of characteristic species might be low.
Intermediate High Low Decline Low
The species most likely to be affected by smothering are the epibiota of sessile animal and algal species that recruit from the plankton and would probably recolonize rapidly. The burrowing species in the sediment (which are the species most likely to be long-lived and slow to recover) are most likely capable of remaining retracted for considerable periods or could burrow upwards through smothering sediment. The fan worm Sabella pavonina would protrude above smothering sediment. If smothering caused deoxygenation, a higher intolerance and lower recoverability would be recorded.
Tolerant Not relevant Not relevant No change Low
Increase in suspended sediment may bring additional food for suspension feeders but may have adverse effects in clogging feeding structures and reducing light penetration. On balance, not sensitive at the benchmark level is suggested.
Tolerant High Not sensitive* Decline Moderate
Decrease in suspended sediment may reduce the food supply for suspension feeders but may allow increased light penetration and therefore improve prospects for algal growth. On balance, not sensitive is suggested.
Not relevant Not relevant Not relevant Not relevant Not relevant
The biotope is subtidal and therefore desiccation is not relevant.
Not relevant Not relevant Not relevant Not relevant Not relevant
The biotope is subtidal and therefore emergence regime is not relevant.
Not sensitive*
The biotope is subtidal and therefore emergence regime is not relevant.
High Very low / none Very High Decline Low
Increased tidal stream velocity may benefit some passive suspension feeders by increasing the supply of food but may also erode the substratum including removal of species attached to the substratum. The long-lived members of the community, the burrowing anemones, are firmly anchored into the sediment and therefore are unlikely to be lost. Removal of the fine grain components of the sediment is likely to be permanent and the biotope is likely to be changed to a different one. As change in biotope will be permanent, intolerance is considered to be high and recoverability very low.
Tolerant* Not sensitive Rise Low
Decreased water flow rate is likely to reduce food supply for passive suspension feeders and allow deposition of fine sediment. Some smothering might occur leading to loss of individuals of species. The long-lived burrowing anemones are unlikely to be affected except perhaps by less food being brought to them. Therefore an intolerance and recoverability of high have been recorded. On resumption of a normal flow regime the minority of species that may have been lost will recolonize from the plankton.
Tolerant Not relevant Not relevant No change Low
The species living attached to the substratum have a wide distribution in the NE Atlantic and the burrowing anemones appear to be southern in their distribution. Therefore, it is not expected that acute or moderately long-term increase in temperature will have an adverse effect.
Intermediate High Low Decline Low
Some of the species in the biotope are known to be adversely affected by an acute decrease in temperature. Sabella pavonina and Megalomma vesiculosum (as Branchiomma vesiculosum) were both severely affected by the cold winter of 1962-63 (Crisp, 1964). The burrowing sea anemones characteristic of the biotope occur from Scotland southwards and may be considered warm water species. However, adults are likely to survive long-term decrease in temperature and it is reproduction and recruitment that is likely to be adversely affected. The species most likely to be affected by cold recruit from the plankton and would recolonize within a few years. Therefore an intolerance of intermediate has been recorded.
Intermediate High Low Minor decline Low
The main effect of increase in turbidity is likely to be a decrease in the abundance of algae in the biotope. For ephemeral species, increased turbidity at the time spores are settling and developing may lead to less algae in that year. In the case of a longer-term increase in turbidity, some perennial species may demise and grazing species may be adversely affected. However, algae settle from the plankton and recovery is likely to be rapid.
Low Very high Moderate No change Low
Decreased turbidity and therefore increased light penetration is likely to lead to an increase in the abundance of algae in the biotope. Whilst providing food for grazing species, algae may smother some species or reduce their ability to suspension feed. Once established, algae will remain in the biotope but will be lost as a part of the seasonal cycle so that recoverability is very high.
High Very low / none Very High Decline Low
The biotope occurs in moderately exposed or sheltered locations most likely where tidal flow is more important than wave action as a structuring factor. Increase in wave exposure may result in displacement of the substratum with consequent scouring. Over one year, sufficient of the substratum might be lost so that the biotope changes to a different one. However, the long-lived members of the community, the burrowing anemones, are firmly anchored into the sediment and therefore are unlikely to be lost. As change to a different biotope will be permanent, intolerance is considered to be high and recoverability very low.
Tolerant* Not sensitive Rise Low
The biotope occurs in moderately exposed or sheltered locations most likely where tidal flow is more important than wave action as a structuring factor. Reduction in wave action is therefore unlikely to have an effect unless cessation of periodic disturbance caused by storms allows one or few species to become dominant to the exclusion of other species. It is more likely that increased stability will allow development of a richer community typical of areas exposed to tidal flow.
Tolerant Not relevant Not relevant Not relevant Not relevant
Whilst species such as Sabella pavonina and Megalomma vesiculosum may be intolerant of vibration and withdraw, no species in the biotope are known to be able to detect noise.
Tolerant Not relevant Not relevant Not relevant Not relevant
Species such as Sabella pavonina and Megalomma vesiculosum may be intolerant of shadowing and withdraw. However, they re-expand rapidly.
High High Moderate Decline Moderate
The biotope would be intolerant of physical disturbance that scraped pebbles or turned them over so that attached species became smothered. However, it is likely that the burrowing anemones would withdraw into the sediment to avoid the factor and therefore have a low intolerance. Species living on the pebbles have planktonic larvae and would probably recolonize rapidly.
Low Immediate Not sensitive No change Moderate
The important characterizing species are sedentary but capable of re-burrowing. Therefore adverse effects would be short-term and recovery would be likely to be rapid.

Chemical Pressures

 IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
No information Not relevant No information Insufficient
information
Not relevant
Insufficient
information.
Heavy metal contamination
No information Not relevant No information Insufficient
information
Not relevant
Insufficient
information.
Hydrocarbon contamination
No information Not relevant No information Insufficient
information
Not relevant
Information has been found on only one of the species mentioned in the biotope description, Urticina felina. Smith (1968) mentions that Urticina felina seemed unaffected during the Torrey Canyon oil spill. However, information on more species is required before an assessment can be made.
Radionuclide contamination
No information Not relevant No information Insufficient
information
Not relevant
No information found.
Changes in nutrient levels
No information Not relevant No information Insufficient
information
Not relevant
No information found.
Not relevant Not relevant Not relevant Not relevant Not relevant
The biotope is recorded from full salinity subtidal situations. Increase in salinity is not likely.
Intermediate High Low Decline Moderate
The biotope is recorded from full salinity situations. It occurs in sea lochs where some dilution of water would be expected during heavy rain and where mixing occurs. However, component algal species are likely to be adversely affected by decreased salinity. Others, such as Sabella pavonina and Megalomma vesiculosum occur in estuarine situations. No information has been found on the likely intolerance of the burrowing anemones. Species that are known to be likely to be affected have planktonic propagules and so are likely to recover fairly rapidly. Therefore an intolerance of intermediate and recoverability of high have been recorded.
Intermediate High Low Decline Low
The biotope occurs in areas where tidal flow is generally moderate and, therefore, oxygenation is good. Decrease in oxygenation due to stagnation or smothering is likely to have an adverse effect on a community attuned to well-oxygenated conditions. However, as the burrowing anemones most likely spend significant periods of time in stagnant burrows, they may be expected to be tolerant of low oxygen conditions at the benchmark level of 2mg per litre for one week. Therefore, although some species may perish, those unlikely to recover rapidly are thought likely to survive.

Biological Pressures

 IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
No information Not relevant No information Insufficient
information
Not relevant
No information found.
Not relevant Not relevant Not relevant Not relevant Not relevant
No alien species are known to occur in this biotope and therefore an assessment of not sensitive is given. However, future spread of species currently in Britain or new arrivals may change this assessment.
Not relevant Not relevant Not relevant Not relevant Not relevant
It is extremely unlikely that any of the species indicative of sensitivity would be targeted for extraction and we have no evidence for the indirect effects of extraction of other species on this biotope.
Not relevant Not relevant Not relevant Not relevant Not relevant

Additional information

No additional information entered.

Importance review

Policy/Legislation

Habitats of Principal ImportanceSubtidal sands and gravels
Habitats of Conservation ImportanceSubtidal sands and gravels
Habitats Directive Annex 1Sandbanks which are slightly covered by sea water all the time
UK Biodiversity Action Plan PrioritySubtidal sands and gravels

Exploitation

No exploitation of this biotope is known to occur.

Additional information

Expect some degree of natural variability in this biotope brought about by seasonality of algal and possibly other species such as hydroids and due to disturbance of the substratum.

Bibliography

  1. Connor, D.W., Dalkin, M.J., Hill, T.O., Holt, R.H.F. & Sanderson, W.G., 1997a. Marine biotope classification for Britain and Ireland. Vol. 2. Sublittoral biotopes. Joint Nature Conservation Committee, Peterborough, JNCC Report no. 230, Version 97.06., Joint Nature Conservation Committee, Peterborough, JNCC Report no. 230, Version 97.06.
  2. Crisp, D.J. (ed.), 1964. The effects of the severe winter of 1962-63 on marine life in Britain. Journal of Animal Ecology, 33, 165-210.
  3. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line] http://www.jncc.gov.uk/mermaid,
  4. Manuel, R.L., 1988. British Anthozoa. London: Academic Press.[Synopses of the British Fauna, no. 18.]
  5. Smith, J.E. (ed.), 1968. 'Torrey Canyon'. Pollution and marine life. Cambridge: Cambridge University Press.

Citation

This review can be cited as:

Hiscock, K. 2001. Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel. 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. Available from: http://www.marlin.ac.uk/habitat/detail/80

Last Updated: 30/11/2001