Species point records from 1982 Smith Lewis littoral survey

This report of a survey carried out under contract to the NCC, describes the shores of Lewis from Mealista on the west coast, north to the Butt of Lewis and south down the east coast as far as the Eye Peninsula, east of Stornaway. Full descriptions of the 33 stations visited are given and excerpts from Powell et al. (1979) included where these also describe the same sites. The area covered in the report is very large, some 150 km of coast excluding the Loch Roag complex. Apart from Loch Roag, the shores are mostly open, exposed to extremely exposed and except in their detail show little variety. Loch Roag, by contrast, is largely sheltered and has a great variety of habitats, rocky shores, various sediments, rapids, lagoons and brackish areas. The rocks are predominantly Lewisian Gneiss which restricts crevice and soft rock fauna. All littoral species which could be identified were recorded, but the list is weighted towards Mollusca. Attention is drawn towards species of particular significance for being at or near the limit of their range. It is noted that autumn populations of mollusca were more diverse and contained higher populations of animals than spring populations. The very exposed and most sheltered shores had the lowest diversity and, normally, lowest numbers of animals, and normally the sheltered sites were the most prolific. The author considers that Lewis is shown by the survey to be as rich and interesting as the more southern isles, and following upon Powell (1979), indicates that some areas are worthy of the highest conservation interest. An appraisal of the biological interest and importance of the shores of the Lewis area is made by the author, the coast being divided into regions. Of these, Loch Roag was found to be extremely rich and interesting in the intertidal, more so than other parts of Lewis with the possible exception of Loch Erisort (Smith, 1982). Judged as one of the most interesting and important areas in western Scotland with its great variety of habitat and high diversity of mollusca, it was assessed as Grade 1+. The coast south-west of Loch Roag is one of the most exposed in the Outer Hebrides, isolated, with an irregular coastline and interesting hanging saltmarsh at the tops of the cliffs. This region is assessed as Grade 1-2 for exposure and wildnerness. The north-west coast of Lewis is a uniform area of coastline which was assessed with reservations as Grade 2. The east coast of Lewis comprised several contrasting zones, much not of any especial importance. Port Skigersta is assessed as Grade 3 and Melbost Point as Grade 1. Records currently considered sensitive have been removed from this dataset.

本报告系受NCC委托执行的一项调查报告，详细描述了路易斯岛的沿岸地带，自西海岸的梅利斯塔向北至路易斯角，向南沿东海岸直至斯图恩韦伊以东的艾伊半岛。报告中对访问的33个站点进行了全面描述，并收录了Powell等人（1979年）的研究节选，其中亦涉及相同地点的描述。报告所涵盖区域辽阔，约150公里海岸线，不包括洛赫罗格地区。除洛赫罗格外，沿岸地带大多开阔，暴露于极端环境中，除细节外，变化甚微。相比之下，洛赫罗格地区则相对隐蔽，拥有丰富的生境多样性，包括岩石海岸、各种沉积物、急流、潟湖和咸淡水区域。岩石主要为路易斯片麻岩，限制了裂缝和软岩生物的生长。所有可识别的沿岸物种均被记录，但名录中软体动物的比例较高。特别指出的是，处于其分布极限或附近的物种。值得注意的是，秋季软体动物的种群更为多样，且动物数量高于春季。暴露程度极高的沿岸地带和相对隐蔽的地带，其物种多样性最低，动物数量通常也最少，而隐蔽地带通常繁殖力最强。作者认为，路易斯岛通过此次调查展现出的丰富性和趣味性堪比更为南部的岛屿，继Powell（1979年）的研究之后，指出某些区域值得最高级别的保护关注。作者对路易斯岛沿岸地带的生物兴趣和重要性进行了评估，并将海岸划分为若干区域。在这些区域中，洛赫罗格地区在潮间带表现出极高的丰富性和趣味性，在路易斯岛其他地区中，可能仅略逊于埃里斯ort湖（Smith，1982年）。作为西部苏格兰最具趣味性和重要性的区域之一，其生境多样性和软体动物的高多样性被评为一级甲等。洛赫罗格西南部的海岸线是赫布里底群岛中最暴露的地区之一，孤立无援，海岸线不规则，悬崖顶部有有趣的悬挂盐沼。该区域被评为一级甲等至一级乙等。路易斯岛的西北海岸线是一个统一的海岸地带，被评为二级，但评估时存在保留意见。路易斯岛的东海岸由几个对比鲜明的区域组成，其中大部分并不具有特别的重要性。斯凯格斯塔港被评为三级，梅尔博斯特角被评为一级。目前认为敏感的记录已从本数据集中移除。