Biodiversity & Conservation

Explanation of sensitivity and recoverability


Physical Factors

Substratum Loss
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Sabellaria spinulosa forms dense aggregations on the substratum and loss of substratum would, therefore, lead to loss of the biotope. An Environmental Statement by Civil & Marine (1994, cited in Anon, 1999r) reported that some dredged samples contained up to 60 % of Sabellaria spinulosa by volume. Where full reviews of the species indicative of sensitivity were available, the species had also been assessed as highly intolerant to substratum loss (see reviews) and it is likely that the baked bean ascidian would also be highly intolerant even though no review was available. Accordingly, intolerance has been assessed as high.

The recovery of this biotope is intrinsically linked to the nature of the substratum. Dredging for aggregates will remove the more gravely sediment from the biotope. The result substrata will be finer and, because Sabellaria spinulosa is associated with sandy and gravely deposits (Seiderer & Newell, 1999), the substratum may be unsuitable for the worms. Also, because aggregate extraction usually occurs in deeper water (>30 m), the substratum rarely gets replaced (Seiderer & Newell, 1999). Recovery has been assessed as high because the biotope is normally found in turbid environments where the worm should be able to build tubes. However, a finer sediment substratum might be less stable meaning that only ephemeral aggregations of the worms, as opposed to established 'reefs' with a diverse associated fauna, may be found.

Smothering
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SS.SBR.PoR.SspiMx occurs on areas with strong to moderately strong tidal streams and it is unlikely that smothering would affect the biotope for long. Feeding in suspension feeders may be interrupted temporarily but the water flow will soon 'clean' the excess sediment from the biotope. Some sediment may become trapped in the nooks and crevices of the reef and this is likely to be of benefit to deposit feeders and infauna. Depending on timing this may interfere with reproduction (in terms, for example, of larval settlement) although only temporarily.

Collins (2003a; 2003b; 2005) reported that Sabellaria spinulosa reefs in Poole Bay were periodically inundated with large sand waves. Such sand waves may be tens of centimetres deep and may smother the reefs for many months (K. Collins, pers. comm.). Although the reef structure may remain, it is most likely that many of the polychaetes themselves, being deprived of oxygen and feeding opportunity, will perish. Accordingly, intolerance has been assessed intermediate. Collins (pers. comm.) has also reported that no Sabellaria spinulosa juveniles have been observed on the reef which will affect the ability of the reef to recover. However, providing the reef structure remains, recovery should occur within 5 years and has therefore been assessed as high (see additional information).

Increase in suspended sediment
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SS.SBR.PoR.SspiMx is only found in very turbid areas due to the fact that Sabellaria spinulosa require sand grains with which to construct their tubes. For the Sabellaria, an increase in suspended sediment could facilitate tube construction and may result in increased populations. However, an increase in suspended inorganic sediment may also clog feeding apparatus although associated fauna are likely to be tolerant of this to a certain degree because of the turbid conditions within which they live anyway. Hill et al. (1997) demonstrated that Alcyonium digitatum sloughed off settled particles with a large amount of mucous. The baked bean sea squirt may experience some damage as a result of scour although this will not affect the viability of the biotope as a whole. Overall, tolerant has been suggested.
Decrease in suspended sediment
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Tube growth in Sabellaria spinulosa is dependent on the presence of suspended particles and a reduction in suspended sediment may hinder tube construction and/or may favour other species to compete successfully with Sabellaria spinulosa. Furthermore, the wealth of suspension feeding polychaetes, bivalves and echinodermata etc may experience a reduction in food availability (organic suspended sediment). Overall, a decline in population density of Sabellaria spinulosa seems likely and other species may experience a reduced scope for growth. Intolerance has been assessed as intermediate since although adults are unlikely to be killed, young recruits may have problems building their tubes and may subsequently perish. Although recovery would be high, it may not happen within one year (as it might for other factors) since a winter storm combined with a reduction in suspended sediment means that the worms may not be able to rebuild their tubes. Overall, sensitivity has been assessed as low.
Desiccation
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Exposure of SS.SBR.PoR.SspiMx to the air and sunshine for one hour will dry the biotope out to a certain degree but the complex nature of the tube matrix (polychaete tubes, amphipod tubes, erect bryozoans etc) mean that water is likely to be trapped in the system therefore keeping it moist. Sabellaria spinulosa, Dendrodoa grossularia, Balanus crenatus and Pomatoceros triqueter are all found in the intertidal and will therefore be tolerant. However, exposure to air will mean that suspension feeders will not be able to feed for the duration of the benchmark and therefore, intolerance has been assessed as low. Recovery will be immediate upon resubmersion.
Increase in emergence regime
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An increase in emergence is not relevant to this circalittoral biotope.
Decrease in emergence regime
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An decrease in emergence is not relevant to this circalittoral biotope.
Increase in water flow rate
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SS.SBR.PoR.SspiMx has been recorded from areas with strong to moderately strong tidal streams (Connor et al., 2004). An increase in flow rate to very strong is likely to be detrimental to the biotope. The aggregation of Sabellaria spinulosa tubes would probably be broken up and redistributed along with much of the infauna. As a result many of the species would be at increased risk of predation from mobile epibenthic predators such as hermit crabs and pycnogonids. Species that use the reef as a 'hard substratum' such as the bryozoa Flustra foliacea and Alcyonidium diaphanum, the baked bean ascidian Dendrodoa grossularia and dead man's fingers Alcyonium digitatummay be lost. Finer particles may be washed away leaving a clean gravel. An impoverished community is likely to be left and biotopes such as SS.SCS.CCS.Pkef may be develop. If cobbles and pebbles became mobile they would result in scour and the mortality of individuals. An intolerance of high has been suggested to reflect the possibility that the entire structure on which the biotope is based could be broken up and washed away.
Decrease in water flow rate
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A decrease in water flow rate could result in the biotope being subjected to negligible flow rates and, particularly in view of the turbid water conditions the biotope often occurs in, siltation and smothering. This is likely to be sufficient to reduce availability of suspended particles, therefore hindering growth and repair of the Sabellaria spinulosa tubes and tube-building species. A reduction in suspended sediment will also affect food availability for both suspension feeders and, after the sediment has settled, deposit feeders. SS.SBR.PoR.SspiMx has been assessed as being of high intolerance to a decrease in water flow rate since juvenile worms would be unable to build their tubes. The remaining worms would slowly perish through lack of food as would other suspension feeders, and mobile fauna including pycnogonids, crabs and amphipods would move away. Overall the recognizable biotope would be lost and there would be a major decline in species diversity. Recoverability is likely to be high (see additional information).
Increase in temperature
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SS.SBR.PoR.SspiMx is a circalittoral biotope and, therefore, it is not accustomed to acute or rapid changes in temperature. However, many of the associated fauna, including Sabellaria spinulosa, Dendrodoa grossularia, Pomatoceros triqueter and Balanus crenatus can be found intertidally and may be tolerant of acute increases in temperature. Furthermore, Sabellaria spinulosa occurs in the Mediterranean and is likely to be tolerant of a chronic increase in temperature although it is generally found in colder waters around in Atlantic and Arctic. However, some of the epifauna may be intolerant to chronic increases in temperature. Balanus crenatus for example has been assessed as highly intolerant to a chronic increase in temperature. In Queens Dock, Swansea where the water was on average 10 °C higher than average due to the effects of a condenser effluent, Balanus crenatus was replaced by the subtropical barnacle Balanus amphitrite. After the water temperature cooled Balanus crenatus returned (Naylor, 1965). Although the loss of this species would not affect the recognizable biotope, intolerance has been assessed as intermediate to reflect the likely loss of some species. Recovery is expected to be high.
Decrease in temperature
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SS.SBR.PoR.SspiMx is a circalittoral biotope and, therefore, it is not accustomed to acute or rapid changes in temperature. However, many of the associated fauna, including Sabellaria spinulosa, Dendrodoa grossularia, Pomatoceros triqueter and Balanus crenatus can be found intertidally and may be tolerant of acute increases in temperature. Sabellaria spinulosa did not appear to suffer mortality during the 1963-64 winter (Crisp, 1964a). The species occurs north to the arctic, as does Balanus crenatus, and is therefore considered tolerant of decrease in temperature. Alcyonidium digitatum can be found as far north as Iceland. However, Pomatoceros triqueter can not build tubes below 7 °C (Thomas, 1940) which, although will not cause the death of the existing population, will mean that subsequent recruitment may fail. However, this will not affect the recognizable biotope and an intolerance of low has been suggested with a very high recovery (see additional information).
Increase in turbidity
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Sabellaria spinulosa thrives in areas of turbid water and the high levels of suspended sediment are a requirement for tube building (see Suspended sediment). SS.SBR.PoR.SspiMx has only been recorded from turbid areas and the biotope has therefore been assessed as tolerant.
Decrease in turbidity
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A decrease in the availability of suspended particles is dealt with in 'Suspended sediment'. In terms of a decrease in light attenuation associated with a decrease in turbidity, SS.SBR.PoR.SspiMx is thought to be tolerant*. Phytoplankton growth is likely to be enhance, therefore providing more food for the suspension feeders.
Increase in wave exposure
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SS.SBR.PoR.SspiMx has been recorded from sheltered to moderately exposed locations. The Sabellaria spinulosa reefs are found between ca 10-30 m and this depth may mitigate any adverse effects associated with increased wave action. A small increase in wave action is likely to resuspended some sediment and if fine organic particles are lost from the biotope this will mean a decrease in food availability for both suspension and deposit feeders. Coarser material may also be resuspended and this may scour erect bryozoans and possible the more fragile tubes of various epifauna. However, strong increases in wave exposure associated with storms will compromise the stability of the matrix of tubes and may break up the reef. In this case there would be a major decline in species richness and intolerance has been assessed as high. Recovery is likely to be high (see additional information).
Decrease in wave exposure
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A decrease in wave exposure at the benchmark level means that SS.SBR.PoR.SspiMx could experience extremely sheltered conditions and, particularly in view of the turbid water conditions the biotope often occurs in, siltation and smothering. Wave action may be required, in the absence of strong tidal flow, to suspend the coarse sand particles needed to build tubes. Reduced wave action may mean the population exists outside of its preferred conditions with insufficient water action to provide sand particles or food. Over the benchmark period the reduction in feeding opportunity for all suspension feeders may prove fatal and species richness is expected to decline greatly. Intolerance has been assessed as high. High levels of recruitment means that recovery could be quite high (see additional information).
Noise
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Some of the species associated with SS.SBR.PoR.SspiMx may respond to noise vibrations though, for example, retreating into their tubes, hiding in crevices or closing their shells (in the case of bivalves) although this is unlikely to adversely affect them and tolerant has been suggested.
Visual Presence
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SS.SBR.PoR.SspiMx is found in very turbid environments and visual presence at the benchmark level is unlikely to affect the associated community. Tolerant has been suggested.
Abrasion & physical disturbance
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Riesen & Reise (1982) revisited a sampling site in the Wadden Sea after more than 50 years and found that Sabellaria spinulosa reefs and the associated fauna had been destroyed by shrimp trawlers. The worm was previously the second most abundant species in the site but in 1980 none were found. Mussel beds or amphipod assemblages (including Bathyporeia sp., Scoloplos sp. and Balanus sp.) had replaced the reefs (Riesen & Reise, 1982; Reise & Schubert, 1987).
Vorberg (2000) observed that Sabellaria spinulosa appeared to be relatively robust and that shrimp trawling could occur without causing visible damage (this study involved the reef being trawled 6 times). However, fragile epifauna including erect bryozoa, dead man's fingers and tube worms may absorb some of the force of the trawl to their detriment.
Abrasion resulting from substratum (cobbles and pebbles) becoming mobile is likely to cause significant damage, especially to erect epifauna and soft bodied organisms such as the baked bean ascidian. Overall, intolerance has been assessed as intermediate. Recovery of the biotope from the benchmark level of disturbance is likely to be high (see additional information). Vorberg (2000) reported that regrowth on damaged sections of Sabellaria spinulosa reefs was significantly higher than on an undisturbed reef. However, Holt et al. (1998) stated that recovery of Sabellaria spinulosa reefs from loss due to bottom fishing was impossible whilst the disturbance continued. In the case of continued disturbance, the Sabellaria spinulosa would be unlikely to form significant aggregations and, as a result, would no longer be defined as a reef because the tubes would lose their ability to stabilize the sediment. This would also affect the associated fauna since the 'hard substratum' element provided by the reef would be lost. Species requiring hard substratum such as Flustra foliacea, Alcyonidium diaphanum, Alcyonium digitatum, Balanus crenatus, Pomatoceros triqueter and some tube-building species would be lost.
Displacement
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Sabellaria spinulosa are not able to rebuild tubes if removed from them (Wilson, 1929). Aside form their own demise, displacement of the worms would lead to the loss of the reef habitat. Although mobile species including hermit crabs, non-tubicolous polychaetes and Pycnogonida would probably escape unharmed, species such as Flustra foliacea, Alcyonidium diaphanum, Alcyonium digitatum, Dendrodoa grossularia, barnacles and calcareous tube worms, if actually removed from the substratum, will not survive. Overall intolerance has been assessed as high with a high recovery (see additional information).

Chemical Factors

Synthetic compound contamination
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Although the larvae of Sabellaria spinulosa are known to be highly intolerant of some oil dispersants (e.g. Smith, 1968), Sabellaria spinulosa has been found to thrive in polluted areas. It was the only epifaunal species found on rock adjacent to an acidified halogenated effluent. It was found at higher densities near the effluent than elsewhere through the exclusion of other species (Hoare & Hiscock, 1974). It may well be that Sabellaria spinulosa has different sensitivities to other synthetic chemicals but this information is not available. Many other polychaetes are known to be highly intolerant to synthetic chemicals although no information was readily available concerning the polychaete species most commonly found in this biotope.

Bryozoans are common members of the fouling community, and amongst those organisms most resistant to antifouling measures, such as copper containing anti-fouling paints (Soule & Soule, 1979; Holt et al., 1995). However, Hoare & Hiscock (1974) suggested that Polyzoa (Bryozoa) were amongst the most intolerant species to the acidified halogenated effluents and reported that Flustra foliacea did not occur less than 165 m from the effluent source.

Barnacles have a low resilience to chemicals such as dispersants, dependant on the concentration and type of chemical involved (Holt et al., 1995). Balanus crenatus was the dominant species on pier pilings at a site subject to urban sewage pollution (Jakola & Gulliksen, 1987). Hoare & Hiscock (1974) found that Balanus crenatus survived near to an acidified halogenated effluent discharge where many other species were killed, suggesting a high tolerance to chemical contamination. However, Holt et al. (1995) concluded that barnacles are fairly sensitive to chemical pollution.

Smith (1968) reported dead colonies of Alcyonium digitatum at a depth of 16 m in the locality of Sennen Cove (Pedu-men-du, Cornwall) resulting from the offshore spread and toxic effect of detergents (a mixture of a surfactant and an organic solvent) e.g. BP 1002 sprayed along the shoreline to disperse oil from the Torrey Canyon tanker spill. Possible sub-lethal effects of exposure to synthetic chemicals, may result in a change in morphology, growth rate or disruption of reproductive cycle.

However, despite the fact that some species are likely to die, the Sabellaria spinulosa will most likely survive and may even increase the extent of their distribution by out-competing more intolerant species. An intermediate intolerance has been suggested to reflect some loss from the rich associated fauna although the biotope per se is likely to remain. Recovery is expected to be high) (see additional information).
Heavy metal contamination
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Experimental studies with various species suggests that polychaete worms are quite tolerant to heavy metals (Bryan, 1984), although no specific information was available concerning the effects on Sabellaria spinulosa.

Bryozoans are common members of the fouling community, and amongst those organisms most resistant to antifouling measures, such as copper containing anti-fouling paints (Soule & Soule, 1979; Holt et al., 1995). Bryozoans were shown to bioaccumulate heavy metals to a certain extent (Holt et al., 1995).

Abra alba can live in polluted sediments (Dauvin, pers. comm.), for example, near Calais where high densities of Abra alba were found in sediment containing 8 mg/g iron and 4 mg/g titanium (Dewarumez et al., 1976). The capacity of bivalves to accumulate heavy metals in their tissues, far in excess of environmental levels, is well known. Bryan (1984) states that Hg is the most toxic metal to bivalve molluscs while Cu, Cd and Zn seem to be most problematic in the field. Hg was reported to have the highest toxicity in bivalves, mortalities occurring above 0.1-1 g/l after 4-14 days exposure (Crompton, 1997).

Pyefinch & Mott (1948) recorded a median lethal concentration of 0.19 mg/l copper and 1.35 mg/l mercury, for Balanus crenatus over 24 hours. Barnacles may tolerate fairly high level of heavy metals in nature, for example they are found in Dulas Bay, Anglesey, where copper reaches concentrations of 24.5 µg/l, due to acid mine waste (Foster et al., 1978).

However, despite the information suggesting an intermediate tolerance of Abra alba and Balanus crenatus to heavy metal contamination, insufficient information was available to assess its effects on SS.SBR.PoR.SspiMx as a whole, specifically Sabellaria spinulosa, and no sensitivity assessment has been made.
Hydrocarbon contamination
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The fact that SS.SBR.PoR.SspiMx is a circalittoral biotope may mitigate the effects of oil pollution on the biotope, since it avoids a direct oiling.

Jacobs (1980) investigated the effects of the Amoco Cadiz oil spill in 1978. The numbers of spionidae polychaetes decreased after the spill. Capitellid polychaetes recovered very quickly, spionids took slightly longer but did recover quickly.

Suchanek (1993) reviewed the effects of oil on bivalves. Sublethal concentrations may produce substantially reduced feeding rates and/or food detection ability, probably due to ciliary inhibition. Respiration rates may increase at low concentrations and decrease at high concentrations. Generally, contact with oil causes an increase in energy expenditure and a decrease in feeding rate, resulting in less energy available for growth and reproduction. However, the Abra alba population affected by the Amoco Cadiz spill benefited from the nutrient enrichment caused by the oil pollution (see Nutrient Enrichment) and Abra alba remained a dominant species over the 20 year duration over which recovery of the community was monitored (Dauvin, 1998).

Amphipods, in general, are highly sensitive to oil pollution (Suchanek, 1993). After the Amoco Cadiz oil spill, for example, there was a reduction in both the number of amphipod species and the number of individuals (Cabioch et al., 1978) and recovery in contaminated sediment was still not complete after eight years.

Smith (1968) reported dead colonies of Alcyonium digitatum at a depth of 16 m in the locality of Sennen Cove (Pedu-men-du, Cornwall) resulting from the offshore spread and toxic effect of detergents sprayed along the shoreline to disperse oil from the Torrey Cannon tanker spill (see synthetic chemicals).

However, despite the information suggesting intolerance of some species to hydrocarbon contamination, insufficient information was available to assess its effects on SS.SBR.PoR.SspiMx as a whole, specifically Sabellaria spinulosa, and no sensitivity assessment has been made.

Radionuclide contamination
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Insufficient information was available with which to assess the sensitivity of SS.SBR.PoR.SspiMx to radionuclide contamination.
Changes in nutrient levels
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An increase in nutrients may be of benefit to the biotope since it may result in enhanced phytoplankton productivity and, therefore, increased food availability. The adverse affects often associated with nutrient enrichment, such as eutrophication and anoxia, are likely to be mitigated by the strong water flows associated with the biotope and tolerant* has been suggested although no increase in species diversity is expected.
Increase in salinity
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SS.SBR.PoR.SspiMx is a circalittoral biotope found in full salinity habitats. An increase in salinity at the benchmark level is, therefore, highly unlikely and not relevant has been suggested.
Decrease in salinity
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SS.SBR.PoR.SspiMx occurs in fully marine environments. The fact that it is circalittoral means that a decrease in salinity is only likely as a result of a reduced salinity outflow pipe or sewage outfall. The fact that Sabellaria spinulosa and much of the associated epifauna occur in the intertidal means that the biotope is likely to be able to tolerate some reduced salinity. Alcyonium digitatum does inhabit situations such as the entrances to sea lochs where low salinity may occasionally occur. However, its distribution and the depth at which it occurs suggest that Alcyonium digitatum is unlikely to survive significant dilution. Balanus crenatus can tolerate salinities down to 14 psu if given time to acclimate (Foster, 1970). At salinities below 6 psu motor activity ceases, respiration falls and the animal falls in to a "salt sleep". In this state the animals may survive in fresh water for 3 weeks, enabling them to withstand changes in salinity over moderately long periods (Barnes, 1953). Spiophanes bombyx is a euryhaline species (Bailey-Brook, 1976; Maurer & Lethem, 1980) and some of the other polychaete species are also likely to be able to tolerate reduced salinity. Pomatoceros triqueter occurs in fully saline coastal waters and has not been recorded from brackish or estuarine waters. Therefore, it is likely that the species will be very intolerant of a decrease in salinity. However, Dixon (1985) views the species as able to withstand significant reductions in salinity.
Ryland (1970) stated that, with a few exceptions, the Gymnolaemata were fairly stenohaline and restricted to full salinity (ca 35 psu) and noted that reduced salinities result in an impoverished bryozoan fauna. Similarly, Dyrynda (1994) noted that Flustra foliacea and Alcyonidium diaphanum were probably restricted to the vicinity of the Poole Harbour entrance by their intolerance to reduced salinity.
Mobile epifauna such as pycnogonids, amphipods and hermit crabs will most likely move away from the area if the reduced salinity is outside their habitat preferences. Despite the likelihood that some species may experience a decline in abundance, the Sabellaria spinulosa are likely to be tolerant of the decrease and therefore, the recognizable biotope will remain. Tolerant has been suggested with low confidence.
Changes in oxygenation
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Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2 mg/l. Balanus crenatus and Alcyonium digitatum have been assessed as highly intolerant to a reduction in oxygen concentration. No information was found on the intolerance of Sabellaria spinulosa to changes in oxygenation although the fact that the biotope occurs in areas with strong water flow means that the effects are likely to be mitigated. Insufficient information was available and no sensitivity assessment has been made.

Biological Factors

Introduction of microbial pathogens/parasites
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Insufficient information was available with which to assess the sensitivity of SS.SBR.PoR.SspiMx to microbial pathogens.
Introduction of non-native species
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It is unlikely that the integrity of the SS.SBR.PoR.SspiMx will be threatened by the introduction of invasive or alien species and tolerant has been suggested.
Extraction
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Sabellaria spinulosa is unlikely to be the target of extraction (for instance, for bait). Extraction of the species is unlikely although dredging may remove populations in some habitats. Fisheries for the pink shrimp Pandalus montagui and brown shrimps (Crangon crangon) (often associated with areas of Sabellaria spinulosa reefs) have been implicated in the loss or damage of reefs. However, Vorberg (2000) undertook experimental and observational studies that indicated only minor damage to tubes and rapid recovery as a result of shrimp fisheries. Nevertheless, populations, especially if as loose aggregations, may be displaced by mobile fishing gear and a precautionary intolerance of intermediate is suggested. Vorberg (2000) suggested that declines might be more associated with changing patterns of currents perhaps associated with construction, dredging and dumping (see Physical Disturbance). However, Sabellaria spinulosa reef areas are known to have suffered widespread and long lasting damage as a result of bottom fishing for (see Physical Disturbance) and intolerance has been recorded as intermediate. Recovery is likely to be high (see additional information).

Additional information icon Additional information

Recoverability
Sabellaria spinulosa is most frequently found in disturbed and polluted conditions and is an r-strategist' (a life strategy which allows a species to deal with the vicissitudes of climate and food supply by responding to suitable conditions with a high rate of reproduction. R-strategists are continually colonizing habitats of a temporary nature (from Baretta-Bekker et al., 1992)). Sabellaria spinulosa occurs in high densities on subtidal gravels that would be expected to be disturbed every year or perhaps once every few years due to storms and in polluted conditions. Areas where Sabellaria spinulosa had been lost due to winter storms appeared to recolonize up to a maximum thickness of 2-3 cm during a single growing season (R. Holt, pers. comm. in Holt et al., 1998).

Although Sabellaria spinulosa is the only key characterizing species within SS.SBR.PoR.SspiMx, the high biodiversity often associated with the reefs will take slightly longer to develop.
However, it is likely that Alcyonium digitatum has a high recovery potential. Its reproductive strategy is to 'broadcast' gametes into the water for fertilization indicates that fecundity is high. The combination of spawning in winter and that the larvae may have a long pelagic life allows a considerable length of time for the planulae to disperse (recruits from other populations can replace impacted populations), settle and metamorphose ahead of the spring plankton bloom.
Balanus crenatus is an important early colonizer of sublittoral rock surfaces (Kitching, 1937) and it heavily colonized a site that was dredged for gravel within 7 months (Kenny & Rees, 1994). Therefore its recovery is also predicted to be high.
Pomatoceros triqueter is fairly widespread and reaches sexual maturity within 4 months (Hayward & Ryland, 1995; Dons, 1927). Larvae are pelagic for about 2-3 weeks in the summer and about 2 months in the winter (Hayward & Ryland, 1995), enabling them to disperse widely. Recovery is therefore likely to be high.
The basked bean ascidian reproduces more than once each year and reaches sexual maturity within a year and its recovery is expected to be high although no further information was available on its recovery potential. Flustra foliacea, Pagurus bernhardus, Scoloplos armiger, Spiophanes bombyx, Lanice conchilega, Ampelisca spp., Abra alba and calcareous tubeworms are all likely to recover within five years. Furthermore, other mobile epifauna will be able to migrate from surrounding areas.


This review can be cited as follows:

Marshall, C.E. 2006. Sabellaria spinulosa on stable circalittoral mixed sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 02/10/2014]. Available from: <http://www.marlin.ac.uk/habitatbenchmarks.php?habitatid=377&code=1997>