Suitability of SACs for Addressing Research Needs

Chapter VIII outlined several areas of research that would contribute to the development of management policies relevant to this biotope complex. The present chapter has made clear that details of community composition and species abundance are lacking for almost all the proposed SACs, Loch Duich being the best-known at present. The table at the end of this chapter summarizes the state of knowledge of the various sites, and lists their perceived relative importance in conservation terms.

The proposed study of sea pen population dynamics could be carried out in Loch nam Madadh, Loch Alsh/Duich or Portland Harbour, all of which contain populations of Virgularia mirabilis in water accessible to divers. The Scottish sites also have the other two sea pen species. A Comparison of Portland Harbour with a Scottish locality would be interesting, as the former is a geographically marginal population probably experiencing a greater range of human impacts.

The effects of experimental trawling on sea pens and megafaunal burrowers could be studied in the Sound of Arisaig, or off the Berwickshire coast if the biotope is shown to have the extent inferred by Foster-Smith et al. (1996), although follow-up diving observations of the trawl paths would not be possible. Whether potentially destructive studies of this kind would be allowed within an SAC is doubtful. The distribution of sea pens, megafaunal burrowers and other benthic biota in relation to local inputs of organic matter (aquaculture, sewage outfalls) could be studied in any of the relevant SACs, and should certainly form part of any routine monitoring programme in semi-enclosed sites with restricted water circulation (eg. Strangford Loch, Loch Duich).

Studies of genetic differentiation between populations could clearly involve SACs in which the species of interest were found. In the case of species with highly localized distributions (eg. Funiculina quadrangularis, Pachycerianthus multiplicatus), genetic evidence would probably confirm suspicions that isolated populations are self-seeding, and hence susceptible to local extinction if their environments are disrupted. The genetic population structure of other, more widespread species (eg. Virgularia mirabilis, Callianassa subterranea) should also be investigated, as this might well reveal hitherto unrecognized barriers to larval dispersal created by coastal geography or hydrographic patterns. Data from studies of this kind would therefore help to determine the likelihood of community recovery following a disturbance event.

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