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Please quote as: Lancaster, J. (Ed.), McCallum, S., Lowe A.C., Taylor, E., Chapman A. & Pomfret, J. (2014). Development of detailed ecological guidance to support the application of the Scottish MPA selection guidelines in Scotland’s seas. Scottish Natural Heritage Commissioned Report No.491. Shallow Tide-Swept Coarse Sands with Burrowing Bivalves – supplementary document. Shallow Tide-Swept Coarse Sands with Burrowing Bivalves Biotope: SS.SCS.ICS.MoeVen Moerella1 spp. with venerid bivalves in infralittoral gravelly sand Offshore/Territorial waters: Territorial The ‘shallow tide-swept coarse sands with burrowing bivalves’ search feature is characterised by infaunal burrowing bivalves and polychaetes. The burrows and tubes of the infaunal species stabilise the sediment and provide structural complexity, which in turn provides habitats for other species. Burrowing infauna also greatly increase bioturbation which has been shown to have a beneficial effect on the maintenance of biodiversity (Widdicombe et al., 2004). Burrowing fauna such as polychaetes significantly influence nutrient fluxes of nitrogen and phosphorus at the sediment-water interface, as their burrowing activity promotes oxygenation of the substrata (Widdicombe & Austen, 1999). Long-lived venerid bivalves, a major constituent of this feature, provide a food source for many species of fish, invertebrates and birds (Malthus et al., 2006; Durkin, 2008; Howson et al., 2009), and represent an example of a bentho-pelagic link. This feature is very sparsely distributed around the UK and Ireland and therefore Scottish records are likely to be of national importance (Connor et al., 2004). Functional Links Functional links and associations with other Priority Marine Features Eelgrass beds: Shallow tide-swept coarse sands with burrowing bivalves may provide a habitat for the formation of Zostera marina/angustifolia beds on lower shore or infralittoral clean or muddy-sand (SS.SMp.SSgr.Zmar). Maerl beds: Scottish maerl beds can occur in association with shallow tideswept coarse sands with burrowing bivalves and, where this occurs, may have an epifauna typified by crustaceans and echinoderms (Malthus et al., 2006). Functional links with the wider Scottish marine ecosystem Long-lived venerid bivalves provide a food source for many species of fish (such as gurnards, dragonets and whiting), crustaceans and echinoderms, representing an example of a bentho-pelagic link (Durkin, 2008). They are important in supporting commercial fisheries e.g. for bivalve and flatfish species, the juveniles of which have been observed to use this habitat (Malthus et al., 2006). Long-lived venerid bivalves can be an important food source for birds (Howson et al., 2009). 1 This name of this group has now been changed to Tellina, although the biotope name remains Moerella 1 The infaunal species within this habitat stabilise sediments and provide structural complexity, in otherwise habitat-poor areas, through the creation of burrows and tubes which increase biodiversity (Widdicombe et al., 2004). Additionally, infralittoral rock with Laminaria hyperborea and Saccharina latissima have been found alongside this habitat (Malthus et al., 2006). Biological Diversity Habitat/Biotope description for Scottish waters The following habitat description is taken directly from JNCC’s Marine Habitat Classification Hierarchy (Connor et al., 2004). Below the box this has been supplemented with additional information specific to Scotland from the scientific literature. Moerella spp. with (SS.SCS.ICS.MoeVen). venerid bivalves in infralittoral gravelly sand “Infralittoral medium to coarse sand and gravelly sand which is subject to moderately strong water movement from tidal streams may be characterised by Moerella spp. with the polychaete Glycera lapidum (agg.) and venerid bivalves. Typical species include Moerella pygmaea or M. donacina2 with other robust bivalves such as Dosinia lupinus, Timoclea ovata, Goodallia triangularis and Chamelea gallina. Other infauna include nephtyd and spionid polychaetes and amphipod crustacea. Another important component of this biotope in some areas is the bivalve Spisula solida (see Khne & Rachnor 1996) which may be common or abundant. In conjunction with .FfabMag3 this biotope may form part of the 'Shallow Venus Community', the 'Boreal Off-shore Sand Association' and the 'Goniadella-Spisula association' of previous workers (see Petersen 1918; Jones 1951; Thorson 1957; Salzwedel, Rachor & Gerdes 1985). Epifaunal communities may be reduced in this biotope when compared to .FfabMag; both types may have surface sand waves which may be indicative of the presence of venerid bivalves (Warwick & Davies 1977). This hypothesis, however, requires testing. Remote grab sampling is likely to under-estimate venerid bivalves and other deepburrowing and more dispersed species such as Paphia, Ensis and Spatangus. In southern areas of the UK and the North Sea, in slightly siltier sand and shelly sand, SCS.MoeVen4 may give way to the other Spisula biotope SSA.SsubNhom5. Together these two biotopes replace the old biotope IGS.Sell6.” (Connor et al., 2004) 2 Tellina pygmaea and T. donacina 3 Fabulina fabula and Magelona mirabilis with venerid bivalves and amphipods in infralittoral compacted fine muddy sand (SS.SSa.IMuSa.FfabMag) 4 Moerella spp. with venerid bivalves in infralittoral gravelly sand 5 SS.SSa.IMuSa.SsubNhom - Spisula subtruncata and Nephtys hombergii in shallow muddy sand 6 SS.IGS.FaG.Sell - Spisula elliptica and venerid bivalves in infralittoral clean sand or shell gravel 2 Studies from the Outer Hebrides provide further information on the diversity of this habitat in Scotland. In the Sound of Barra this habitat has been recorded containing both T. pygmaea and T. donacina, however T. donacina was recorded in very few locations, and T. pygmaea was the dominant tellin, found during both infaunal and epifaunal surveys (Harris et al., 2007). The polychaete Nephtys cirrosa and amphipod Bathyporeia were also recorded in abundance in this habitat (Harris et al., 2007). In the Sound of Harris only T. pygmaea was found, although a wide range of associated habitats and species were described occurring alongside this habitat (Malthus et al., 2006). Habitats such as those dominated by Laminaria hyperborea and Saccharina latissima were found adjacent to this habitat, as were eelgrass beds and maerl beds (Phymatolithon calcareum) (Malthus et al., 2006). Additional infaunal organisms present included Arenicola marina, Amphiura sp., Lanice conchilega and the burrowing anemone Cerianthus lloydii. Epifauna recorded in the Sound of Harris included Echinus sp., Asterias sp., Carcinus sp., hydroids and ascidians (e.g. Ascidia mentula) and a diatom film was also found on top of the sediment. Species diversity Records from the Outer Hebrides (Sounds of Barra and Harris) indicate the typical levels of biodiversity present in this habitat in Scotland. The number of species per grab (0.1m2) varied, with generally more species being found in the Sound of Harris (853 species; Malthus et al., 2006) compared to the Sound of Barra (10-29 species; Harris et al., 2007). Species richness indices values per grab (Shannon Index) also varied from 1.866-3.325 in the Sound of Harris (Malthus et al., 2006) to 1.10-2.93 in the Sound of Barra (Harris et al., 2007). Key and characterising Species These have been taken from JNCC’s biotope description (Connor et al., 2004). Biotope type SS.SCS.ICS.MoeVen Key species for identification The tellins T. pygmaea and T. donacina. 3 Additional characterising species Glycera lapidum, S. solida, A. latreillii, Anemonia viridis, Nemertea, Nematoda, Pisione remota, Glycera lapidum, Streptosyllis websteri, Nephtys cirrosa, Aonides paucibranchiata, Spio filicornis, Spiophanes bombyx, Lanice conchilega, Bathyporeia pelagica, Apseudes latreillii, Pagurus bernhardus, Liocarcinus depurator, Carcinus maenas, G. triangularis, Spisula solida, Chamelea gallina, T. ovata; Dosinia lupinus; Echinocyamus pusillus; Callionymus lyra, Pomatoschistus minutes, Chondrus crispus, Polyides rotundus, Gracilaria gracilis, Saccharina latissima and Ulva spp. Coherence Typicalness This habitat is found on coarse, gravelly infralittoral sand (0-20m) on exposed open coasts and in estuaries, subject to moderately strong tidal water movement (Connor et al., 2004). It is characterised by Tellina spp. with the polychaete Glycera lapidum and venerid bivalves. Other infaunal species include other polychaete, tanaids (shrimp-like crustaceans) and sand hoppers (Connor et al., 2004). Many of the faunal components of this habitat are moderately robust as the environment is relatively dynamic and sand ripples may be seen on the surface of the sediment (Connor et al., 2004). This habitat has been found in association with eelgrass beds and maerl beds in Scotland, and where this occurs, may have an epifauna characterised by crustaceans and echinoderms (Malthus et al., 2006). Ecological variations across Scottish waters The species composition of this habitat is thought to be largely determined by substratum characteristics and hydrodynamics (Durkin, 2008). Around the islands of Yell, Fetlar and Unst (Shetland) associated species vary according to location and include Moerella pygmaea (now Tellina) in the majority of samples, as well as maerl P. calcareum at a few locations, together with the bivalve Spisula elliptica, the razor shell Ensis arcuatus, and the polychaetes L. conchilega, Glycera spp., Spio spp., Spiophanes spp. and Aonides paucibranchiata (Howson,1988; Hirst et al., 2013). The habitat was found often situated adjacent to records of the related but deeper SS.SCS.CCS.MedLumVen7 biotope. In Lamlash Bay (Arran) this habitat can be found in, muddy, gravelly sand with some shell fragments and supported clumps of red algal turf (Aglaothamnion sp. and other species) and bootlace weed C. filum. Mobile species included Frequent edible crabs C. pagurus and hermit crabs Pagurus bernhardus, the gobies P. pictus and P. minutus, and juvenile common starfish A. rubens. Some samples contained relatively high densities of other venerid bivalves including the striped venus Chamelea gallina and smooth Artemis Dosinia lupinus, and low densities of the polychaetes Mediomastus fragilis and Lumbrineris gracilis (Munro et al., 2012). These samples share characteristics with the related SS.SCS.CCS.MedLumVen biotope and areas of sea bed within Lamlash Bay were considered to comprise a mosaic of SS.SCS.ICS.MoeVen and SS.SCS.CCS.MedLumVen biotopes in 2010 (Munro et al., 2012) 7 Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel 4 Viability Very little information exists for the bivalves present in this community, with no information available regarding population densities or Minimum Viable Populations. There are also only a few locations where this search feature is known within Scotland. In most known instances (e.g. Malthus et al., 2006) the area covered by this feature is much smaller than would be needed to protect the entire life cycle of the bivalves. Therefore, regardless of the size of the feature, it would be recommended that examples of its entire extent are protected. Where the feature occurs in discrete patches, amongst other habitats such as maerl beds, seagrass beds, kelp or reefs, it is recommended that all of the patches of this search feature within specific examples of these habitat mosaics are protected. Fragmentation No detailed information was available on the level of fragmentation typical for this habitat. However, it is known to occur in small discrete patches amongst other habitats. Indicators of Least Damaged/More Natural Up to date information on the sensitivity of this search feature to pressures associated with human activities are included in the Feature Activity Sensitivity Tool (FeAST; Marine Scotland, 2013). Below, information on indicators of damage and naturalness are taken from MarLIN sensitivity data (Durkin, 2008). Table 1: Indicators of damage and naturalness Indicators of Naturalness Indicators of Damage Potential Sources of Damage Continued presence of this biotope and its characteristic species, including S. solida and other populations of infauna and sessile epifauna present. Loss of habitat feature and/or associated species diversity particularly loss or reduction of S. solida. Physical disturbance, substrate removal, changes to hydrography. No reduction in species diversity and/or abundance. Notable reductions in species abundance and/or diversity. Pollution/Eutrophication Risk Assessment The details of the assessment of risk for each MPA search feature is addressed in a separate report (Chaniotis et al., 2014). Recovery Potential Physical damage/substrate removal hydrographic change MarLIN lists the .MoeVen biotope’s ability to recover from substratum loss and physical damage as high, however, this will depend on whether or not sufficient numbers of individuals remain to supply recruits to the area (Durkin, 2008). A loss of key characterising species will take up to 5 years to recover, due to the time required for the majority of key bivalves to reach maturity (Durkin, 2008). However, the rarity of some characterising species in British waters means that there may be a lack of recruit sources to seed a particular area, causing recovery to be hindered or not possible. 5 Changes to hydrography Permanent changes in the hydrography caused by development or coastal defence may cause changes in the benthic conditions rendering the habitat unsuitable for recolonisation. MarLIN lists the .MoeVen biotope as being intermediate in its tolerance to increases in water flow rate and its sensitivity is moderate since its ability to recover is high if the activity is only temporary (Durkin, 2008). Contamination by pollutants MarLIN lists this .MoeVen biotope as being highly intolerant to contamination with pollutants and its sensitivity as moderate since its ability to recover from pollution is high after the cessation of the impacting activity (Durkin, 2008). Eutrophication MarLIN lists the .MoeVen biotope as being intermediate in its tolerance to eutrophication and its sensitivity as moderate since its ability to recover from eutrophication is high after the cessation of the impacting activity (Durkin, 2008). Geographical Variation This search feature is uncommon in the British Isles, and in Scotland has only been recorded in the West and North territorial MPA regions in territorial waters. The majority of these records are from Shetland and Orkney with some instances on the west coast of Scotland (e.g. Loch Slapin, Loch Kishorn and Arran) and Outer Hebrides (e.g. Sounds of Barra and Harris) (Connor et al., 2004 ). Geographical context Beyond Scotland this habitat is very scarcely distributed within the UK and Ireland, with a few records reported from south Devon and Cornwall, the Scilly Isles and north-west Wales (Connor et al., 2004). Scottish records of this habitat are therefore likely to be of national importance. 6 References Connor, D. W., James A. 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. JNCC, Peterborough Chaniotis, P.D., Cunningham, S., Gillham, K. & Epstein, G. 2014. Assessing risk to Scottish MPA search features at the MPA regional scale. Final report produced by the Joint Nature Conservation Committee, Scottish Natural Heritage and Marine Scotland for the Scottish Marine Protected Areas Project. Durkin, O.C. 2008. Moerella spp. with venerid bivalves in infralittoral gravelly sand. Marine Life Information Network: Biology and Sensitivity Key Information Subprogramme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 12/04/2010]. Available from: http://www.marlin.ac.uk/habitatecology.php? habitatid=388&code=1997 Harris, D.B., Malthus, T.J., Karpouzli, E., Moore, C.G., Lyndon, A.R., Mair, J.M., Service, M. & Mitchell, A. 2007. Biotope mapping of the Sound of Barra, Scotland. Scottish Natural Heritage, Commissioned Report No.258 (ROAME No. F06PA04). Hill J., Pearce, B., Georgiou, L., Pinnion, J., & Gallyot, J. 2010. Meeting the MPA Network Principle of Viability: Feature specific recommendations for species and habitats of conservation importance. Natural England Commissioned Reports, Number 043. Hirst, N.E., Kamphausen, L.M., Cook, R.L., Porter, J.S. & Sanderson, W.G. 2013. The distribution and status of proposed protected features within the Fetlar and Haroldswick MPA proposal. Scottish Natural Heritage Commissioned Report 599 Howson, C.M. 1988. Marine Nature Conservation Review: Survey of Shetland, Foula and Fair Isle 1987. Vol. 1: Report. Report to Nature Conservancy Council from Field Studies Council Oil Pollution Research Unit. Howson, C. M., Steel. L., & Gillham, K. 2009. Identification of priority marine features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388. Malthus, T.J., Harries, D.B., Karpouzli, E., Moore, C.G., Lyndon, A.R., Mair, J.M., Foster-Smith, B., Sotheran, I. & Foster-Smith, D. 2006. Biotope mapping of the Sound of Harris, Scotland. Scottish Natural Heritage, Commissioned Report No. 212 (ROAME No. F01AC401/2). Marine Scotland. 2013. Features, Activities, Sensitivities Tool (FeAST) online resource. Available from: http://www.scotland.gov.uk/Topics/marine/marine-environment/FEAST-Intro Munro, C.D., Baldock, L., Brown, K. & Lindsley-Leake, S. 2012. Monitoring of marine habitats and species in Lamlash Bay, Arran: methodological developments and 2010 baseline data. Scottish Natural Heritage, Commissioned Report. Widdicombe, S. & Austen, M.C., 1999. Mesocosm investigation into the effects of bioturbation on the diversity and structure of a subtidal macrobenthic community. Marine Ecology Progress Series, 189, 181-193. Widdicombe, S. & Austen, M.C. 1998 . Experimental evidence for the role of Brissopsis lyrifera (Forbes, 1841) as a critical species in the maintenance of benthic diversity and the modification of sediment chemistry Journal of Experimental Marine Biology and Ecology, 228, 241–255 7 Widdicombe, S., Austen, M.C., Kendall, M.A., Olsgard, F., Schaanning M.T, Dashfield, S.L, & Needham. H.R. 2004. Importance of bioturbators for biodiversity maintenance: indirect effects of fishing disturbance. Marine Ecology Progress Series, 275, 1-10. 8