Habitat 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.

本报告系根据NCC合同所进行的调查报告，详细描述了路易斯岛自西海岸的梅利斯达至北端的路易斯角，向南至斯图恩韦伊以东的艾伊半岛东海岸的沿岸地区。对所访问的33个站点进行了全面描述，并收录了Powell等人（1979年）的研究摘录，其中也描述了相同地点。报告覆盖区域广阔，约150公里海岸线，不包括罗格湖复合体。除罗格湖外，沿岸地区大多开阔，暴露于极端环境中，除了细节上显示出的多样性外，整体上变化不大。相比之下，罗格湖大部分地区受到保护，拥有丰富的生境多样性，包括岩石海岸、各种沉积物、急流、潟湖和咸水区域。岩石主要为路易斯片麻岩，这限制了裂缝和软岩生物群的生长。记录了所有可识别的沿岸物种，但列表倾向于贝类。特别指出那些处于或接近其分布极限的物种。值得注意的是，秋季贝类的种群多样性更高，动物数量也多于春季。暴露程度高和受保护程度低的沿岸地区生物多样性最低，通常动物数量也最少，而受保护的地点通常是繁殖最旺盛的地方。作者认为，路易斯岛的调查结果表明，其与更南部的岛屿一样丰富和有趣，并继Powell（1979年）的研究之后指出，某些地区值得最高的保护关注。作者对路易斯岛沿岸的生物兴趣和重要性进行了评估，将海岸划分为不同的区域。在这些区域中，罗格湖在潮间带被证明是极为丰富和有趣的，这在路易斯岛的其它地区中，除了可能包括艾里斯波特湖（Smith，1982年）之外，更为突出。作为西部苏格兰最有趣和重要的地区之一，拥有丰富的生境和贝类的多样性，其被评为一级加。罗格湖西南部的海岸是外赫布里底群岛中最暴露的地区之一，孤立，海岸线不规则，悬崖顶部有有趣的悬挂盐沼。该区域被评为1-2级，以暴露和荒野著称。路易斯岛的西北海岸是一片统一的海岸区域，被评为2级。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。斯基格斯塔港被评为3级，梅尔博斯特角被评为1级。目前认为敏感的记录已被从本数据集中移除。