Scotland’s Land Cover

Contents

• introduction
• Origins of Land Cover Mapping
• Scottish Biogeography
• Climate
• Geology and Soils
• Time
• Land Cover Mapping
• The Land Cover Map of Scotland
• Future Landscapes of Scotland
• Support Materials
• About

1. Origins of Land Cover Mapping

An appealing characteristic of the Scottish scene is that it varies so greatly over short distances – influenced by the juxtaposition of land and sea, and the environmental influences on land of topography and climate, geology and soils. Scotland’s land cover has evolved through time, essentially since the last deglaciation over 10,000 years ago – to create a varied pattern of land cover which is subject to continuing natural change and modification by human activities.

Definitions

Elements of

• land form (e.g. topography and coast),
• land cover (e.g. grassland and woodland), and
• land use (e.g. crofting, cultural artefacts and settlements)

inform our perception and appreciation of a varied and varying Scottish landscape.

Land use denotes the human employment of the land, so that a change in land use at any location may involve a shift to a different type of use, say from farming to residential, or a change in the intensity of use, for instance livestock stocking rates. Such changes in land use affect land cover.

Land cover is the focus of interest in Advances 4. It denotes the physical state of the land, such as the quantity and type of surface vegetation, water and earth materials. The abundance and diversity of Scotland’s fresh waters is a distinctive feature. A change in land use can impinge upon water quality (physical, chemical and biological properties) and flow (including sub-surface hydrology and impediments).

Land cover change may involve conversion from one class of land cover to another, such as from heather moorland to woodland, or modification involving a change of condition or composition within a land cover category.

Despite our sense of familiarity with it, and its importance to many aspects of economic and social life, it may seem surprising that the land cover of Scotland has only comparatively recently been comprehensively mapped.

The Land Utilisation Surveys

When regarding the detailed geography of the British Isles in the 1920s, the pioneering geographer Dudley Stamp encountered “serious gaps in knowledge”. He found that the locally-based studies of the day covered only small parts of the country and that methodological differences meant that they were scarcely comparable. In consequence he set about organising a “field-to-field survey of the whole country, covering every acre, and recording its use”². He required a scheme “simple enough to be understood and applied by voluntary workers with varied or with little training”, and concluded that it would “best be done through the educational organisation” of schools and universities.

His enthusiasm is inspirational: “The work of recording land use is a magnificent educational exercise involving accurate observation and map reading, and … inculcated an early appreciation of the unit in a democracy and induced a local pride in achievement”.

The ‘Land Utilisation Survey of Great Britain’ was carried out in the years before the outbreak of the Second World War, mainly in 1931-1933 (base year 1932). When later viewing the generalised map he observed that “even with the most casual glance at the map one cannot fail to notice the extraordinary contrasts between one part of the country and another … it would be difficult to find any area of comparable size anywhere in the world which offers such amazing variety”.

“The first national land use survey coincided with the nadir of the great inter-war depression”. In 1960 Alice Coleman thus inaugurated a second land use survey for England and Wales, to “provide a record of the more prosperous face of this country” and an indication of land utilisation changes which had taken place. Voluntary surveyors again included schools. Before the advent of geographical information systems (GIS), which nowadays provide an electronic means of integrating such datasets, “County Land Use Memoirs” were used to “adduce full geographical correlations with the help of geological and soil maps, meteorological data, agricultural and census figures, and all available cognate material”³.

Following in the footsteps of Stamp and Coleman, ‘The 1996 Land Use - UK Survey’ was developed by the Geographical Association “to stimulate interest in Britain’s contemporary land-use, to discover the views and visions of young people about the environment at the present time and to provide an enjoyable and educational vehicle for purposeful fieldwork in schools”⁴ . The sample-based land cover mapping exercise of the rural and urban environment involved 1400 schools (half of them primary) throughout the United Kingdom.

Contemporary Land Cover Maps

A range of methods have been employed to classify and describe the land cover of the United Kingdom, from detailed botanical survey to remote sensing^5,6, . All mapping relies on generalisation to simplify complexity, for instance in plant-species associations. It is necessary to be able to detect and describe features of interest consistently. The rules employed for discriminating between different land cover types (generally referred to as features) is termed classification. Classification rules need to be defined before data collection commences, and they determine the view of land cover which is portrayed in the resultant map. A GIS enables an electronic map to be reclassified, and thus to provide different views (e.g. by aggregating different features in the classification) or themes (e.g. all woodland).

Only direct observation in the field is currently capable of differentiating vegetation communities (the species composition of plants growing in characteristic associations). More general vegetation features can be detected from air photography or satellite imagery for the mapping of habitats or, to be more precise, biotopes (e.g. into different types of grassland, woodland, moorland, etc.). Habitat mapping is faster and cheaper than field survey and requires less ecological expertise.

Air photography and satellite imagery are examples of remote sensing. Discriminating between features on the ground is inferred through the manual interpretation of visual images or the computerised classification of electronic images.

The Land Cover of Scotland

Scotland-wide studies which contribute to our knowledge of land cover are:

• The Land Cover of Scotland 1988 (LCS88), interpreted from air photography produced by the Macaulay Land Use Research Institute⁸ (this is the subject of interest in Advances 4),
• the National Countryside Monitoring Scheme (NCMS), interpreted from air photography produced by Scottish Natural Heritage⁹ (this is the subject of interest in Advances 5), and
• the Countryside Survey 1990 (CS1990), undertaken by the Institute of Terrestrial Ecology¹⁰ with a GB-wide field survey with a land cover map derived from the classification of satellite imagery (reference is made to the Countryside Survey in Chapter 2).

All were interpreted from remotely sensed imagery and captured digitally for manipulation and analysis on geographical information systems.