|Basic Information||Biotope classification||Ecology||Habitat preferences and distribution||Species composition||Sensitivity||Importance|
Image Sue Scott - Gaping file shell nest on mixed muddy substratum, with nest opened and Limaria hians exposed. Image with ca 15 cm.
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SS.IMX.FaMx.Lim recorded () and expected () distribution in Britain and Ireland (see below)
The information below is based on survey data and the few detailed studies available: Gilmour (1967), Minchin (1995), Connor et al. (1997), JNCC (1999), and Hall-Spencer & Moore (2000b). Limaria hians is an active suspension feeder on phytoplankton, bacteria, and detritus.
The carpet of byssus threads, coarse sediment, and shell produced by Limaria hians provides refugia, and substratum for attachment for a wide variety of sessile and sedentary species.
Other suspension feeders include sponges, hydroids (e.g. Kirchenpaueria pinnata, Nemertesia spp., and Tubularia spp.), bryozoans (e.g. Bugula spp.) , soft corals (e.g. Alcyonium digitatum), epifaunal and infaunal bivalves (e.g. Modiolus modiolus and Mya truncata respectively), tube worms (e.g. Pomatoceros triqueter), ascidians and small crustaceans. If present, the brittlestars, e.g. Ophiura spp. or Ophiopholis aculeata, may also suspension feed.
Kelp (e.g. Laminaria hyperborea) and foliose red algae (e.g. Delesseria sanguinea or Phycodrys rubens) probably provide primary production in the form of detritus and dissolved organic matter, and via grazing by amphipods, isopods, chitons, gastropods (e.g. Gibbula cineria, Tectura virginea or Calliostoma zizyphinum) or sea urchins (e.g. Psammechinus miliaris). Suspension feeders, including Limaria hians obtain primary productivity from phytoplankton and benthic and epiphytic microalgae.
The faunal turf of hydroids and bryozoans is probably grazed by echinoderms (e.g. Henricia oculata and Echinus esculentus) or gastropods (e.g. Calliostoma zizyphinum) or preyed on by polychaetes (e.g. the sea mouse Aphrodite aculeata), nudibranchs (e.g. Onchidoris sp.) and pycnogonids (e.g. Achelia echinata) (Gordon, 1972; Salvini-Plawen, 1972: Ryland, 1976).
Mobile predators include crabs such as Cancer pagurus and Necora puber, which probably eat a variety of epifauna including gastropods, small crustacea and bivalves. The nests of Limaria hians provide a defence against most predators (Merrill & Turner, 1963: Gilmour, 1967). In addition, Limaria hians can also discard its tentacles leaving a predator with a sticky, unpalatable meal while the rest of the animal makes its escape by swimming. The tentacles of Limaria hians (especially the longer tentacles) secrete an adhesive and irritant mucus, that has been shown to deter a variety of predators from crabs to fish; e.g. the flounder was reported to spit out Limaria hians (Gilchrist, 1896; Merrill & Turner, 1963; Gilmour, 1967). However, the starfish Asterias rubens and Marthasterias glacialis prey on a wide range of epifauna and molluscs including Limaria hians (Minchin, 1995).
Fish such as juvenile cod Gadus morhua, small-spotted catshark (dogfish) Scyliorhinus canicula, and dragonets Callionymus lyra and gobies probably prey on mobile and sessile epifauna on the reef and may take damaged specimens of Limaria hians (JNCC, 1999; Hall-Spencer & Moore, 2000b).
Starfish, brittlestars, hermit crabs (e.g. Pagurus bernhardus), crabs and the common whelk Buccinum undatum probably act as epifaunal scavengers within this biotope (JNCC, 1999; Hall-Spencer & Moore, 2000b).
The nest galleries support a number of detrivores, deposit feeders, scavengers and predators. For example, polychaetes (e.g. Polynoe spp. and Flabelligera affinis), flatworms and small crustaceans are probably scavengers within the nests, preyed on by polychaetes such as Glycera lapidum and Nephtys hombergi and ribbon worms) (Hall-Spencer & Moore, 2000b).
The macroalgae in the biotope may be expected to show seasonal changes in growth and development; for examples see Delesseria sanguinea and Laminaria hyperborea reviews. In temperate waters most bryozoan species tend to grow rapidly in spring and reproduce maximally in late summer, depending on temperature, day length and the availability of phytoplankton (Ryland, 1970). Several species of bryozoans and hydroids demonstrate seasonal cycles of growth in spring/summer and regression (die back) in late autumn/winter, over-wintering as dormant stages or juvenile stages (see Ryland, 1976; Gili & Hughes, 1995; Hayward & Ryland, 1998). For example, the fronds of Bugula species are ephemeral, surviving about 3-4 months but producing two frond generations in summer before dying back in winter, although the holdfasts are probably perennial (Eggleston, 1972a; Dyrynda & Ryland, 1982). The hydroid Tubularia indivisa is annual, dying back in winter (Fish & Fish, 1996), while the uprights of Nemertesia antennina die back after 4-5 months and exhibit three generations per year (spring, summer and winter) (see reviews; Hughes, 1977; Hayward & Ryland, 1998; Hartnoll, 1998). Many of the bryozoans and hydroid species are opportunists (e.g. Bugula flabellata) adapted to rapid growth and reproduction (r-selected), taking advantage of the spring/summer phytoplankton bloom and more favourable (less stormy) conditions (Dyrynda & Ryland, 1982; Gili & Hughes, 1995). Some species such as the ascidians Ciona intestinalis and Clavellina lepadiformis are effectively annual (Hartnoll, 1998). Therefore, the biotope is likely to demonstrate seasonal changes in the abundance or cover of the epifauna and macroalgae.
Hall-Spencer & Moore (2000b) studied a Limaria hians bed over a 5 year period, while Minchin (1995) reported the that Limaria hians was abundant in the Moross Channel, Mulroy Bay from 1978-1982 and had been recorded from Mulroy Bay a hundred years previously. This suggests that Limaria hians beds, once established, are probably relatively stable unless affected by human impacts or storms (see sensitivity).
This biotope is characterized by dense populations of Limaria hians where the nests coalesce into a carpet or reef over the sedimentary substratum, and in which individual Limaria hians are not visible (Connor et al., 1997; JNCC, 1999). For example, in the Creag Gobhainn area of Loch Fyne, Limaria hians formed a reef 10-20cm high, composed of >700 individuals/m² and covering several hectares (Hall-Spencer & Moore, 2000b) and 216-584 /m² were reported in the Moross Channel, Mulroy Bay in 1980 (Hobson, 1980 cited in Minchin, 1995). The carpet of nests covers and hence stabilizes the substratum. In addition, the carpet of nests provides substratum for the attachment for a diverse array of sessile and sedentary invertebrates, niches and refugia for mobile epifauna, and the nests themselves support a burrowing infauna and scavengers. The exact composition of the associated community probably varies with location depending on the species present in the surrounding area.
The associated macroalgae, epifauna and interstitial fauna probably depend on locality and recruit from the surrounding area. Many hydroids and most bryozoans, ascidians and probably sponges have short lived plankton or demersal larvae with relatively poor dispersal capabilities. Exceptions include Nemertesia antennina and Alcyonium digitatum and hydroids that produce medusoid life stages, which probably exhibit relatively good dispersal potential. Hydroids and bryozoans are opportunistic, rapid growing species, with relatively widespread distributions, which colonize rapidly and are often the first groups of species to occur on settlement panels. Sponges and anemones may take longer to recruit to the habitat but are good competitors for space. Recruitment in epifauna communities is discussed in detail in the faunal turf biotopes MCR.Flu, CR.Bug and in Modiolus modiolus beds (MCR.ModT).
Mobile epifaunal species, such as echinoderms, crustaceans, and amphipods are fairly vagile and capable of colonizing the community by migration from the surrounding areas, probably attracted by the refugia and niches supplied by the Limaria hians carpet. In addition, most echinoderms and crustaceans have long-lived planktonic larvae with high dispersal potential, although, recruitment may be sporadic, especially in echinoderms.
This review can be cited as follows:
Tyler-Walters, H. 2003. Limaria hians beds in tide-swept sublittoral muddy mixed sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 01/04/2015]. Available from: <http://www.marlin.ac.uk/habitatecology.php?habitatid=112&code=1997>