The paper reviews the recent history and present state of knowledge of the flora and its geographical relationships. Key environmental factors are identified and the range of habitats is discussed, with some comment on plant communities. Recent accounts of island flora and plant communities are available for Skye, Rhum and Mull in contrast to the Outer Hebrides where none are available for the main islands. There is no checklist for the flora of the Inner Hebrides, since the islands are best described individually, not as a group.

The geography of the flora and plant communities is discussed and related to that of the Outer Hebrides and the Scottish mainland. Inter-island relationships are described and related to habitat differences. Compared with the Outer Hebrides, machair and extensive wetland habitats are lacking through much of the Inner Hebrides, but there is a much greater extent of upland and mountain environment. There is much more woodland in the Inner Hebrides but the woodland development does not attain the levels of the adjacent mainland.

Despite the greater extent of upland and mountain environments in the Inner than in the Outer Hebrides, many of the plant communities of central Scotland are absent while those of western character are well represented.

Woodland is native throughout the Inner Hebrides at low elevations wherever exposure and soil conditions permit. Although mostly destroyed in the distant past, sufficient remnants remain to characterise Hebridean woods and provide a basis for their study and conservation. Surveys have revealed that the types represented are those dominated by wych-elm, ash, oak, birch, hazel, alder and sallows. All but the smallest and most exposed islands have remnant woodlands but the widest variety of types and the most demanding species occur on the larger islands of Mull and Skye. The woodland flora is rich in oceanic species and poor in continental, boreal plants characteristic of the mainland pine–birch woodlands, although Scots pine probably once occurred sparsely in the primaeval woodland.

The most powerful factor influencing between-site variation in the woodland flora is geology, with wychelm, ash and hazel associated with soils on Durness limestone, Mezozoic rocks and basalts, and oak and birch characteristic of the Torridonian sandstones, acid Moine rocks, Lewisian gneiss and granites. There is little active conservation; the most pressing need is protection from grazing and fire to ensure long-term survival.

The vegetation and surface structure of two ombrogenous mires from the Inner Hebrides are described. Two-way indicator species analysis and hand sorting of these data are used to identify vegetation communities. The surface patterning of both sites is examined using levelling data which are related to the water table. From this, four significant surface features are recognised: hummock, ridge, hollow and pool. The relationship between the vegetation communities and these features is examined, and the two study sites subsequently compared in terms of these small-scale features. The ombrogenous mires of the Inner Hebrides are then related in the same way to other mire systems described by previous authors.

Of just under 1000 species of bryophyte known in the British Isles, 597 are recorded in the Inner Hebrides. This diversity of species is due to several factors: the suitability of the climate for bryophyte growth, the rich variety of bryophyte habitats and the presence of several phytogeographical elements in the islands.

Bryophyte species occur in varying numbers in almost all habitats from the spray zone at high water mark to the tops of mountains. Compared with the Outer Hebrides and the adjacent mainland, certain bryophytes are absent from the islands. This is largely due to the scarcity of dune slacks in the Inner Hebrides, and the poorer development of high mountain habitats.

Examples are given of a number of typical Inner Hebridean habitats together with their characteristic bryophyte species.

Naturally the Inner Hebrides are rich in species with an oceanic distribution in the British Isles. These are analysed into groups based on their world distributions. A number of species with strongly disjunctive distributions are thought to be Tertiary relicts in the British flora.

A list of the bryophytes recorded in the Inner Hebrides is appended giving presence or absence in each island or group of islands.

The results of eight days' recording and collecting of lichens on the island of Colonsay are presented. A wide range of habitats were studied but particular attention was paid to the two relict oak-woodlands and some areas of calcareous machair. An impressive total of 342 lichen taxa was recorded, and two species were added to the British flora.

When one speaks of the Inner Hebridean fungi one is referring to the floras of Mull (1,744 spp.) and Rhum (905 spp.) for these are the only islands where the fungi have been seriously studied; only a few collections have been made in Eigg, Coll and Tiree, Raasay and Colonsay while Islay and Jura have been almost entirely neglected by mycologists. Recently attention has been paid to the fungal flora of Skye where over 75 stations have been examined. However, only 6% of the species recorded for VCs 102–104 are not recorded from Mull.

Fifty years ago James Ritchie declared that “in recent times we are looking in Scotland upon Evolution in its course”. The basis for Ritchie's remark was the large number of distinct taxa which have been described on Scottish islands, mainly on the Outer Hebrides. The most effective ingredient in producing taxonomic distinctiveness is isolation, particularly when the isolated form is founded by a small group of organisms which will almost inevitably differ genetically from its ancestral population. Subsequent adaptation may produce divergence between two related but isolated groups, but the process of differentiation will be fairly slow, since natural selection must depend upon the inherited variation present, never mind consideration of evolutionary ‘cost’, etc.

The Inner Hebrides are ecologically very diverse, but the gene-flow between animals and plants living on them and on the mainland of Scotland must be much greater than is the case for Outer Hebridean populations. Notwithstanding, subspecifically distinct races of field mice, voles, shrews, and stoats have been described, and clinal variation shows that adaptive changes have taken place in several bird and lepidopteran species.

The Inner Hebrides offer excellent experimental opportunities to measure gene-flow between different islands, and between islands and mainland. It should be possible to estimate some of the evolutionary forces involved in producing species differentiation, as well as in local extinctions.

The breeding and wintering birds of the Inner Hebrides are dealt with in this paper; seabirds and waterfowl have been described by Bourne and Harris (1979) and by Ogilvie and Atkinson-Willes (1983*). The bird populations of the Inner Hebrides are generally poorly documented, though Islay and the Small Isles are exceptions.

Taking the Hebrides as a whole, stepwise regression analysis indicates that the number of landbird species to have bred on islands is significantly related to the following factors: the number of island habitats, island area, distance from the mainland and distance from the nearest large island. Islands near the mainland and large islands will contain more species than isolated islands of similar ecology and size. Agricultural change and island depopulation have resulted in the decrease of many bird populations. Plantations have increased the number of breeding bird species. Birds are treated either by species or by group. Appendices include work on corncrakes, Canna seabirds and sea eagles.

The island of Islay posssesses by far the largest population of wintering wildflowl in the Inner Hebrides; there are 18,000-20,000 barnacle geese Branta leucopsis and 4,000 Greenland white-fronted geese Anser albifrons jiavirostris. There is also a small flock of greylag geese A. anser. Most of the commoner dabbling and diving ducks spend the winter in small numbers, with a flock of 1,000 scaup Aythya marila the most important. A few hundred pairs of eider Somateria mollissima breed, and up to 3,000 wintering or moulting birds have occurred offshore. Other breeding duck are few in number, including up to five pairs of common scoter Melanitta nigra. Whooper swans Cygnus cygnus spent the winter in the past but are now common on passage only. Barnacle geese have trebled in numbers in the last twenty years, leading to complaints of agricultural damage, and a subsequent increase in shooting and disturbance followed by a recent decline in numbers. Annual data on populations, productivity and losses are presented. Greenland white-fronted geese have varied less in numbers, but shooting has increased and the situation is reviewed. All other wildfowl occurring on the island are dealt with briefly.

Wildfowl habitat in the Inner Hebrides. Excluding Islay, consists mainly of sheltered bays and sealoches, while fertile freshwater lochs are uncommon, the best being on Tiree. The known breeding distribution and winter concentrations of species are described and an indication is given of overall status and histroical background. There are very few records from many of the smaller islands, and even those from Skye, Tiree and Mull are restricted to between one and four winters.

Eider and red-breasted merganser are probably the two commonest wintering speices, but there are no good estimates of total numbers. Flocks of 500–600 eider occur round Skye, and summer moulting concentrations of 1.400–1.700 merganser in the Sound of Gigha indicate a high pouplation. Between 2.400–2.600 barnacle geese Branta leucopsis spend the winter on many small. Uninhabited islands throughtout the region. Wigcon. Teal, mallard and tufted duck occur in flocks in several places, with maxima between 150 abd 350.

Whooper swan Cygnus cygnus, Greenland white-fronted goose Anser albifrons flavirostris, shelduck, shoveler, pochard, goldeneye Bucephala clangula, long-tailed duck Clangula hymelis and goosander all winter regularly, though rarely in flocks of more than 100.

Published studies on the Coleoptera of the Inner Hebrides from 1853–1981 are briefly reviewed and a full bibliography is provided. This is supplemented with data obtained from museum and private collections, unpublished manuscripts, etc., and the results of extensive surveys undertaken on eight of the islands during 1980 and 1981. Doubtful published records are discussed and records of 716 species are accepted. To these, 221 species have been added as new to the Inner Hebrides, together with numerous new island records. A comprehensive table lists the 937 species of Coleoptera and shows on which of the 15 largest, or best documented islands, they occur. Details of the limited known fauna for three of the remaining islands are also given. Our knowledge of the fauna of the Inner Hebrides remains very incomplete. Only 54% of the species recorded are known from the Outer Hebrides, whilst their faunal relationships with the Scottish mainland cannot be assessed until surveys of similar detail have been done on the west coast.

A checklist of 576 species of lepidoptera has been produced for the islands of Rhum, Canna, Coll and Colonsay. Within these islands the status and habitat requirements of selected species, including some Scottish rarities, are discussed. Brief mention is made of some species which occur in other islands but which have not been recorded in the four sample islands. The status of Zygaenidae is discussed. This family is of outstanding interest in that five of the seven species recorded in Scotland occur in the Inner Hebrides. One is restricted to Skye, whilst another now appears to be confined in Britain to the Isles of Mull and Ulva.

The earliest evidence of prehistoric activity in Scotland comes from Jura. Most of Jura has been rather inimical to settlement, in comparison with other islands of the southern Inner Hebrides—Colonsay and Oronsay, Gigha and Cara, and Islay—all endowed with deposits more useful to man than Jura. Land use and settlement in these islands spread from the coasts into and up the river valleys until the first half of the19th century, after which they retreated. There have, however, been several waves of retreat and readvance.

This paper assesses the present stage of research in the chronicle of these changes in the southern islands, pointing to some of the unanswered questions. The archaeological, onomastic and historical evidence is briefly examined against a slowly changing environment that has been relatively favourable, in a Hebridean context. Areal expansion, upward extension and intensified use of the land increased in momentum, with interruptions, after the late medieval period. The time of greatest change began just after the middle of the 18th century and lasted for another century.

Elements of this change and its effects on settlement are discussed, using records and maps from private and official archives, topographic and other writings, and population and agrarian censuses. The important role of landlords, their agents and subsequent planners in instituting, and even containing, change is briefly assessed. In the southern Inner Hebrides an unusual, non-crofting landscape resulted: an estate, farming and sporting landscape, with, in the case of Islay, over a dozen industrial and service villages.

The characteristic ‘Highland Problem’ of landscape and land use, increasingly ill-suited to the needs of later 19th and 20th century economy and society, has been less evident in these islands than in others in the Hebrides, although they now show disturbing trends. Present land use and settlement are briefly examined.

The Inner Hebrides consist of a long chain of islands varying greatly in topography and extending from Skye in the North to Islay off the southern coast of Argyll. The group includes the islands of Raasay, South Rona, Soay. Scalpay, Pabay, Canna, Rhum, Eigg, Muck, Coll, Tiree, Colonsay, Oronsay, Jura, Gigha, Luing, Scarba, Mull, Ulva, Gometra, Lismore, Kererra, Shuna and Iona.

There are in addition numerous small islands which, although no longer cultivated or inhabited are utilised for grazing stock by farmers and crofters from adjacent islands and from the mainland.

Agricultural land use and livestock production on the islands is governed largely by soil type, elevation, exposure and grazing quality. An aspect of increasing importance is the proportion of arable land relative to hill and mountain grazing. Cattle stocks in particular tend to be limited to the quantity of winter fodder which can be home-conserved since the prohibitive costs of importing fodder by road and sea are a serious constraint on the profitability of cattle raising.

Until recent times cropping on the arable land of many of the islands followed a traditional seven year rotation of oats, roots and potatoes, sow-out to grass under a cereal nurse crop followed by three years of hay conservation or grazing. During the past ten years there has been an increasing swing from mixed cropping towards grasslands production. On many farms and crofts the emphasis on conservation lies in hay-making but silage has become increasingly popular particularly on larger farm units in Islay, Gigha, Luing and Mull.

Current statistics indicate that the livestock population of the islands consists of 166,250 breeding ewes, 13,850 beef type breeding cows and 1,770 dairy cows together with their followers.

Sheep are mainly of Blackface breed but on Skye are found some 12,000 Cheviots with further Cheviot flocks located on Eigg, Canna, Rhum, Scalpay and Soay.

On the fertile machairs of Tiree and Iona sheep stocks are composed of Leicester/Down X ewes which are mated usually with Suffolk and X Suffolk rams.

Dairy farming is centred mainly on Islay and Gigha. There is a creamery on each of those islands, the Islay Creamery processing some 3,043 million litres of milk annually while the creamery unit on Gigha has a throughput of 1·431 million litres.

Transport costs, ageing population in the crofting sector and the vast number of small units all contribute to the many problems which face islands agriculture at the present time.

Forestry development in the Inner Hebrides is largely confined to Islay, Jura, Mull, Skye, Raasay and Scalpay. Tue value of the forest industry is highlighted in producing a raw material for industry, providing employment and supporting the island infrastructure. Factors such as exposure, degraded soils and problems of marketing which force the forester to limit the choice of species to a few hardy saleable species are also described. Established consultation procedures are preserving the essential interests of competing land users by the rational apportionment of land to various uses and by good forest design. Creation of diversity in commercial plantations which is essential for habitat improvement by both natural means and modern management practices is described.

A checklist of vertebrate fauna which frequent these new forests is provided together with an assessment of their status.

Shellfish fishing, traditionally associated with crofting areas, has expanded greatly in Scotland generally, and particularly in the Inner Hebrides, during the past 30 years. Landings from Inner Hebrides waters in 1979 were valued at about £11 millions. Processing factories and storage installations have facilitated marketing.

The seas around the Inner Hebrides provide a wide variety of habitats, from the fine mud necessary for Norway lobsters, through the sandy gravel on which scallops live, to the rocky sea bed inhabited by lobsters.

The most valuable fisheries, those for Norway lobsters and scallops, are post-war developments. In both, the stocks appear to be in a healthy state. Landings in the traditional lobster fishery have declined recently and the stocks are giving some cause for concern. Periwinkles and queens make useful contributions to the economy. Pink shrimps and squat lobsters, though not sufficiently abundant to support a directed fishery, form a useful, occasional by-catch. Squids are caught sporadically, but their availability is very variable. The crab stocks could stand much greater exploitation.

The review examines the commercial potential of deposits of iron ores, lead, chromite, silica-rich rocks and diatomite that the Inner Hebrides possesses. Working quarries are described and their reserves estimated. Careful assessment of all the available data suggests that only the Raasay Ironstone, two diatomite deposits in Skye and an operating sand and gravel deposit at Allt Anavig in Skye merit further, detailed investigation.

The methods of nature conservation applied within the Inner Hebrides are those which are now standard throughout Britain and are governed by legislation. The procedures for habitat or site protection and species protection are illustrated in the descriptions of the reserves, the Sites of Special Scientific Interest and the protected species within the archipelago. The reserves and sites cover interests in the geology, geomorphology, zoology, botany and ecology of the islands and the surrounding seabed. National Scenic Areas are also mentioned. Relationships between nature conservation and the uses of land and sea are discussed. With the exceptions of the commercial exploitation of the island pastures in sheep husbandry, with much uncontrolled burning, and the exploitation of fin fish and shell fish and consequent widespread depletion of stocks, the Inner Hebrides are comparatively undisturbed by modern industrial development.