Species point records from 1990 UMBSM North & South Uist and Benbecula sealochs survey

The Uist island chain in the Outer Hebrides is formed of Lewisian gneiss and is generaly low-lying with extensive and complex fresh and brackish water systems and a heavily indented eastern coastline. Five sealochs on the east coast, Lochs Boisdale, Skipport, Uiskevagh, Eport and Maddy, were surveyed during 1990 as part of the survey of Scottish sealochs. These were selected as being representative of the lochs present in the islands and share three major features. Facing east, they all have a limited exposure gradient. None is deep although Lochs Skipport and Maddy reach 40m in their entrances. Finally, as fiardic systems of varying degrees of complexity, they possess numerous islands and wide shallow basins in their upper reaches, connected to each other and to the main loch by narrow, often intertidal, channels with strong tidal streams. Several of these basins are brackish, Loch Obisary being a classic example; most are extremely sheltered. This combination of features means that the lochs possess a wide variety of habitats. Shellfish and salmon farms are established in all of the lochs surveyed and Ascophyllum nodosum is harvested from the shores for the alginate industry. Loch Maddy is an MCA and a part of the loch is included in the Loch an Duin SSSI. Loch Obisary, which is connected to Loch Eport by a sill 4 m above chart datum, is an SSSI and there are several others in the area. A considerable amount of survey work has been carried out in the Uists since McIntosh (1866) visited the islands, with notable littoral studies by Lewis (1957) and Powell et al. (1979) and several NCC-commissioned sublittoral surveys. Seventy sites were surveyed in total of which 62 were sublittoral and 8 littoral; 34 habitat/community typse were described. The distribution of these within each loch was broadly the same. The lochs were characterized by a variety of shallow sheltered habitats and communities, many of which were subject to tidal streams. There is a full transition from fresh and brackish to marine communities in these systems; only the marine component was investigated during this survey. Infralittoral bedrock communities ranged from rich Laminaria hyperborea forest at the entrances to cape-form L. saccharina forest in the most sheltered regions; the latter was unusually diverse. Deep bedrock, with Swiftia pallida and Diazona violacea, was restricted to the loch entrances. Sheltered circalittoral boulders were rare and were dominated by ascidians. The tide-swept Loch Eport entrance channel held a rich hydroid community not found elsewhere in the area. Sublittoral sediments varied from sandy mud with Virgularia mirabilis in the more seaward sections of the lochs to very soft, flocculent mud with dense populations of the rare holothurian Labidoplax media in the more sheltered basins. Tidal streasms of varying strengths flowed through shallow channels which had a corresponding range of communities from coarse sediments and maerl with Neopentadactyla mixta and Sabella pavonina to scoured bedrock. Particularly unusual were channels in upper Loch Maddy which supported extremely large laminarians and Halidrys siliquosa with a very rich sponge epiphyte community. Little littoral sediment was found, with most shores being bedrock or boulder and dominated by dense blankets of Ascophyllum nodosum. In the areas of strong tidal flow, rich under-boulder shore communities were found, characterised by ascidians and sponges. More exposed shores in the entrances supported barnacle and red algal communities with scattered fucoids. Eleven habitat/community types and 13 species have been provisionally assessed to be of Local, Regional, National or International importance. Records currently considered sensitive have been removed from this dataset.

乌斯特岛链位于外赫布里底群岛，由路易斯片麻岩构成，整体地势低平，拥有广阔而复杂的淡水及咸淡水系统，以及深度切割的东部海岸线。在1990年对苏格兰塞尔洛克的调查中，东部海岸的五处塞尔洛克——博伊塞尔、斯基波特、尤斯基维格、伊波特和马迪——被选为样本进行考察。这些塞尔洛克因其代表性而被选中，它们共具有三大特征：面向东方，均具有有限的暴露梯度；尽管深度有限，斯基波特和马迪在入口处深达40米。最后，作为不同复杂程度的菲尔德系统，它们在上游拥有众多岛屿和宽阔的浅水盆地，通过狭窄、常为潮间带的渠道与彼此及主湖相连，并拥有强劲的潮流。其中一些盆地为咸淡水，奥比萨里湖便是典型的例子；大多数则极为隐蔽。这些特征的组合意味着这些湖泊拥有丰富的栖息地。被调查的所有湖泊中均建立了贝类和水产养殖场，而从岸边采集的Ascophyllum nodosum用于藻酸盐工业。马迪湖是MCA的一部分，其一部分区域被纳入洛奇安杜因特别保护区。奥比萨里湖，通过4米高于海图基准面的门槛与伊波特湖相连，是特别保护区，该区域还有其他几个保护区。自麦金托什（1866年）访问岛屿以来，在乌伊斯特岛进行了大量的调查工作，其中以刘易斯（1957年）和鲍威尔等人（1979年）的显著海岸研究以及数个由NCC委托的亚潮带调查为著。总共调查了70个地点，其中62个为亚潮带，8个为海岸带；描述了34种栖息地/群落类型。这些类型在每个湖泊内的分布大致相同。这些湖泊以多种浅水隐蔽的栖息地和群落为特征，其中许多都受到潮流的影响。在这些系统中，从淡水和咸淡水群落到海洋群落存在着完整的过渡；本次调查仅研究了海洋组成部分。亚潮带基岩群落从入口处的丰富层状海带森林到最隐蔽区域的海湾形糖海带森林不等；后者的多样性尤为突出。深水基岩，生长着Swiftia pallida和Diazona violacea，仅限于湖泊入口处。隐蔽的环潮带巨砾极为罕见，主要由海鞘类动物占据。被潮水冲刷的伊波特湖入口渠道拥有丰富的水螅类动物群落，该群落在该区域其他地方未曾发现。亚潮带沉积物从湖泊更外侧的沙质淤泥和拥有Virgularia mirabilis的海藻到更隐蔽的盆地中非常柔软、絮状的淤泥，其中密集分布着稀有海参Labidoplax media。不同强度的潮流流经浅水渠道，这些渠道对应着从粗颗粒沉积物和珊瑚藻类到磨蚀基岩的多种群落。马迪湖上游的渠道尤其异常，这些渠道支撑着极大的层状海带和Halidrys siliquosa，以及丰富的附生海绵类动物群落。 littoral 沉积物很少，大多数海岸为基岩或巨砾，由密集的Ascophyllum nodosum覆盖。在强潮流区域，发现了丰富的底石岸群落，其特征为海鞘和海绵。在入口处的较暴露海岸，支持着贻贝和红藻类动物群落，其中散布着苔藓。初步评估认为，11种栖息地/群落类型和13个物种具有地方、区域、国家或国际重要意义。目前被认为敏感的记录已被从该数据集中移除。