Natural environment of the Inner Hebrides—an introduction

Abstract

SynopsisThe Inner Hebrides have a natural history which, in geological time, dates from the Archaean and, in human history, from the Mesolithic 7000–6500 BC. The archipelago was a great attraction to scientists and historians in the 19th and 20th centuries which has resulted in an extensive literature. It started with Martin in 1703 and following a steady interest for about two centuries has blossomed in many spheres of scientific and other interests over the past 50 years. The islands are geologically outstanding and much pioneering work has been done on their Lewisian and Torridonian basement, Mesozoic fossiliferous sediments and Tertiary ring structures which has been of value in the understanding of the geology of the European and the North Atlantic provinces. The geomorphological features include glaciated landscapes, raised beaches and those caused by marine erosion and accretion.The character of the islands is in great part determined by a mild, wet and windy climate. The soils are mainly ‘mor’ in character with localities of ‘mull’ soils overlying limestone or calcareous sand. Similarly, the vegetation and freshwaters are mainly oligotrophic except when overlying limestone or shell-sand which support meso- and eutrophic communities of plants and animals. There are important assemblies of breeding seabirds in Rhum and Treshnish Isles and wintering flocks of geese and other wildfowl in Islay. The large islands have populations of red deer, grey seals, common seals and otters breed throughout the islands. The Inner Hebrides hold stocks of plants and animals which are genetically distinct from those of the mainland and some have Lusitanian and American affinities.The islands are mainly used for the grazing of sheep and cattle with local small-scale arable cropping in crofting and farming. Forestry is possible only in the sheltered parts of the larger islands or in small sheltered islands; the main crops are sitka spruce and lodgepole pine but there are broadleafed woodlands around large houses in many islands and gardens with exotic, sub-tropical plants, shrubs and trees. There are pelagic and demersal marine fisheries, shell fisheries and fish farms mainly growing salmon, rainbow trout and mussels. The mineral resources on a commercial scale, are minor. The nature conservation interest is high with two National Nature Reserves (including Rhum) and 62 Sites of Special Scientific Interest.