@article {Smith1979, title = {Mollusca of rocky shores: Lewis and Harris, Outer Hebrides}, journal = {Proc. R. Soc. Edinburgh. Sect. B. Biol. Sci.}, volume = {77}, year = {1979}, pages = {173{\textendash}187}, abstract = {

The history of previous molluscan work in the Outer Hebrides shows that most work has been done offshore, and that the littoral zone of Lewis and Harris has been neglected. Mollusc populations of different macro- and micro-habitats were examined empirically, and compared and contrasted with each other. Habitats have been chosen to exhibit as wide a variety of environment as possible, from the wave-lashed exposed rocks facing the Atlantic to the very sheltered sea lochs opening into the Minch. The richness and diversity of the fauna is noted.

}, keywords = {Harris, Invertebrates, Lewis, littoral, Loch Roag, Marine, Marine Molluscs, molluscs, Outer Hebrides}, author = {Smith, S M} } @article {Waterston2011a, title = {The inland waters of the Outer Hebrides}, journal = {Proc. R. Soc. Edinburgh. Sect. B. Biol. Sci.}, volume = {77}, year = {1979}, pages = {329-351}, publisher = {Cambridge University Press}, abstract = {

The Outer Hebrides comprise approximately 1\·3\% of the land area but 15\·8\% of the area of standing waters of Great Britain. Streams there are generally small and only three are as large as fifth order. The majority of the lochs occur below 200 m altitude and are less than 25 ha in area. A total of 1375 stream systems enter the sea, and drain the land mass through 9240 stream segments. There are just over 6000 lochs, of which less than half are connected to these networks. Most of the water systems are on geologically base-poor rock or soil, and less than 3\%, situated on machair, are base-rich and eutrophic. The islands, due to their situation, receive precipitation in the form of very dilute sea water (with some non-marine sulphate probably derived from fossil fuel combustion) and this leads to unusual concentrations of chloride in the inland waters. Metamorphic rocks are resistant to weathering, so there is usually little variation in the composition of fresh waters except in the machair areas, where calcareous sands affect calcium concentrations and alkalinities.

The flora and fauna reflect the aqueous conditions and there are some unique successions of species from high to low salinities even in the same water body. The lochs provide a wide range of habitats for aquatic vegetation, ranging from the rich machair lochs to the oligotrophic peaty lochs (which show marked similarities with their counterparts on the mainland). Three broad categories can be delineated on the basis of their water quality and vegetation: brackish lochs with varying degrees of marine influence, calcareous machair lochs which may also be affected by sea connections, and the peaty lochans of low alkalinity. A few brackish water animals are sufficiently euryhaline to exist in the machair lochs, which are otherwise dominated by freshwater species. The occurrence of chloride in inland waters enables some crustaceans, e.g. Neomysis integer, Gammarus duebeni and Diaptomus wierzejskii to extend into what are poor freshwater habitats. The main constituents of the freshwater fauna are molluscs and arthropods, and a few species of euryhaline fishes, i.e. salmon, sea and brown trout, three-spined and ten-spined sticklebacks and eels. There are some populations of non-migratory charr. No amphibians are present.

}, keywords = {Invertebrates, Outer Hebrides}, issn = {0269-7270}, doi = {10.1017/S0269727000012781 }, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8378833\&fulltextType=RA\&fileId=S0269727000012781}, author = {Waterston, A.R and Holden, A.V. and Campbell, R.N and Maitland, P.S.} } @article {Waterston2011, title = {The macrofauna of brackish and fresh waters of the Loch Druidibeg National Nature Reserve and its neighbourhood, South Uist}, journal = {Proc. R. Soc. Edinburgh. Sect. B. Biol. Sci.}, volume = {77}, year = {2011}, month = {dec}, pages = {353{\textendash}376}, publisher = {Cambridge University Press}, abstract = {

The macrofauna of brackish and fresh waters of the Loch Druidibeg National Nature Reserve and its neighbourhood, South UistThree main types of Hebridean freshwater lochs occur in the Loch Druidibeg National Nature Reserve; eutrophic calcareous machair lochs near the Atlantic coast, mesotrophic lochs on the edge of the moor and oligotrophic lochs on the peatlands. Chloride/calcium concentrations, highest in lochs near the sea, fall away rapidly inland and are lowest in the moor lochs. The fauna of eutrophic and mesotrophic lochs includes a few euryhaline brackish-water species Potamopyrgus jenkinsi, Diaptomus wierzejskii, Neomysis integer and Gammarus duebeni. G. duebeni alone penetrates the oligotrophic lochs. Freshwater sponges are widespread but are absent from the machair lochs and there are no triclad planarians. The fauna of fast and slow stream segments is described. Loch Bee, a man-made lagoon, unlike the open brackish lochs of North Uist, is an unstable habitat and its fauna has changed considerably since it was investigated in 1933. The fauna consists mainly of brackish-water species and a few stenohaline marine species which are confined to its seaward ends. The sequence of faunistic change in the Howmore estuary, Lochs Roag and Fada, a Site of Special Scientific Interest (SSSI), is described; the brackish-water fauna is reduced by the volume of fresh water passing through the system. A brief account is given of the unusual dominance of Hyalinella punctata and Potamopyrgus jenkinsi in Loch Ardvule (SSSI), South Uist.

}, keywords = {Invertebrates, Loch Druidibeg, Uist}, issn = {0269-7270}, doi = {10.1017/S0269727000012793}, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8378836\&fulltextType=RA\&fileId=S0269727000012793}, author = {Waterston, AR and Lyster, IHJ} } @article {Welch2011, title = {Survey of the invertebrate fauna of sand dune and machair sites in the Outer Hebrides during 1976}, journal = {Proc. R. Soc. Edinburgh. Sect. B. Biol. Sci.}, volume = {77}, year = {2011}, month = {dec}, pages = {395{\textendash}404}, publisher = {Cambridge University Press}, abstract = {

During June and July 1976 the Institute of Terrestrial Ecology carried out a limited invertebrate survey on 18 sites in the Outer Hebrides.

Portable battery-operated UV light traps were installed at each site and left to operate for eight nights. Bad weather in June greatly reduced the numbers of Lepidoptera caught. During July moths were trapped at 16 of the sites. Details of the combined catches are given. Pitfall traps were also installed at all sites and all beetles, spiders, harvestmen, snails, millipedes, centipedes and woodlice have been identified. In addition a list of species of littoral Coleoptera recorded from 24 Hebridean localities is given.

This survey was part of a much wider project around the coasts of Scotland, commissioned by the Nature Conservancy Council, to whom a full report will be submitted when identification and analysis of the results has been completed.

}, keywords = {Arachnids, Coleoptera, Dunes, Invertebrates, Lepidoptera, Machair, molluscs, Outer Hebrides}, issn = {0269-7270}, doi = {10.1017/S0269727000012811}, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8378842\&fulltextType=RA\&fileId=S0269727000012811}, author = {Welch, R. C.} }