2. Scottish Biogeography

The distributions of plants and animals are influenced by environmental factors and human activity. Environmental factors include topography (elevation, aspect, slope, landform, relief), climate (particularly temperature, rainfall, exposure, and continental and maritime influences), geology, soils, and time. Geographically, the interaction of these underlying factors has created mosaics of habitats and micro-habitats to which plant species and vegetation communities have evolved.

Within a relatively small land area, a range of climates can be experienced in Scotland – such as the mild, wet, maritime conditions associated with the prevailing Atlantic winds and relatively warm waters of the North Atlantic Drift along the west coast; the arctic-alpine conditions of the higher mountains inland; the exposed northern coasts and islands; and the more continental conditions to the east.

Variations in environmental conditions in space and through time, together with human influences, govern the current distribution of plants. Where the distribution of plants is constrained by environmental factors, ‘natural zones’ might be envisaged. Different taxonomic groups of plants, such as mosses or higher plants (flowering plants and ferns) and their associated animal species, can reveal distributions which show the ways in which they are adapted to, and exploit, ecological niches that the environmental conditions provide.

Distinctive aspects of Scotland’s biogeography

The Institute of Terrestrial Ecology has combined environmental and landscape variables into 32 ‘Land Classes’ for Great Britain¹¹. These can be used to illustrate some of the distinctive aspects of Scotland’s biogeography [Figures 2.1, 2.2 & 2.3].

An inherent difficulty with mapping land cover is that “the concept of land does not show single, uniform distinct boundaries between different types, rather it is composed of a series of more or less continually varying trends - trends in climate, geology, physiography or landform, soil, vegetation, land use, rural and urban development”¹².

Biogeography is the study of the patterns of distribution of plants and animals in space and time, and the identification of factors that determine or limit these distributions.

Land cover is a continuum, influenced by environmental variables and human activities. Land cover mapping requires lines of differentiation to be drawn. Boundaries may be distinct (e.g. a woodland edge) or more gradual (e.g. grassland transition).

Which land cover features might you wish to map in your area? What level of detail would be appropriate, in terms of classification (i.e. ability to discriminate between different features), resolution (i.e. the minimum mappable area in terms of the smallest length or area at which features will be differentiated) and scale (i.e. the ground area to be projected on the resulting map)?

Figure: 2.1a

West and Northern Fringe (description)
Environmental Characteristics Described by ITE Land Classes

Among the 32 Land Classes, Classes 29, 30 and 32 have the following characteristics:

Feature	Class	Description
Description	29	Sheltered coasts with varied land use, often crofting.
	30	Exposed coasts dominated by bogs.
	32	Windswept low hills covered with bogs.
Geography	29	West Scotland
	30	Extreme West Scotland
	32	N.W. Scotland and Isles.
Land Form	29	Indented coastlines with cut platforms and raised beaches.
	30	Mainly peneplains with meandering streams, sometimes with low hills.
	32	Peneplain surfaces or low ridges, sometimes coastal.
Topography	29	Uneven topography, usually with easy slopes but some steeper areas at low or medium-low altitudes.
	30	Variable from complex to almost flat, at medium-low extending to medium-high altitudes.
	32	Variable from complex to even rounded slopes, mainly at medium-low altitudes.
Landscape	29	Complex scenery containing many contrasting elements.
	30	Open moorlands near to the sea, with rocky outcrops and lochs.
	32	Bleak moorlands, often with scattered lochs and eroding peat hags.
Land Use	29	Mainly open range grazing, but also some crofting.
	30	Open range grazing and crofting.
	32	Mainly open range grazing, but some pasture.
Soils	29	Mainly peats, but also rankers and brown earths.
	30	Mainly peats, with some peaty podzols.
	32	Mainly peats but some rankers.
Vegetation	29	Mainly peatland and moorland types, but also some bracken.
	30	Mainly peatland, with some moorland trees.
	32	Predominantly peatland types, but also some moorland.

Produced from the Countryside Information System, which is the joint Copyright of the Department of the Environment Transport and the Regions, and the Institute of Terrestrial Ecology. It may be reproduced for educational purposes only. For further information see http://mwnta.nmw.ac.uk/ite/cisflier.html

Figure: 2.2a

Uplands (description)
Environmental Characteristics Described by ITE Land Classes

Among the 32 Land Classes, Classes 21, 23 and 24 have the following characteristics:

Feature	Class	Description
Description	21	Upper valley, rocky outcrops and bogs
	23	High mountain summits, with well drained moorlands
	24	Upper steep mountain slopes, usually bog covered
Geography	21	Central and N. Scotland
	23	Central and N. Scotland
	24	Central and W. Scotland
Land Form	21	Peneplain surfaces with complex drainage, or broad ridges with indistinct summits
	23	Ridges, scarps and corries leading to mountain summits or rarely glaciated valleys
	24	Glaciated valley sides, often reaching from base to rocky summits sometimes peaks emergent from peneplains
Topography	21	Predominately quite steep hillsides, but also some more moderate slopes
	23	Extremely steep hillsides, sometimes less so, with the land at high altitudes
	24	Precipitous and extremely steep slopes with land at high altitude
Landscape	21	Bleak upland landscapes, sometimes enclosed by walls or fences and afforested
	23	Open mountainous landscapes with wide vistas
	24	Rugged mountain scenery, often rocky with fast slowing streams
Land Use	21	Open range grazing or forest
	23	Limited open range grazing
	24	Limited open range grazing
Soils	21	Peats, peaty gleys or podzols
	23	Peats, peaty podzols, podzols and brown rankers
	24	Brown rankers, peats or peaty podzols, some peaty gleys
Vegetation	21	Moorland or peatland types, with some rough grassland
	23	Mainly moorland types, but also mountain grassland and peatland types
	24	Mainly peatland types, but also montane grassland and moorland

Figure: 2.3a

Mixed and Arable Farmland (description)
Environmental Characteristics Described by ITE Land Classes

Among the 32 Land Classes, Classes 25, 26 and 27 have the following characteristics:

Feature	Class	Description
Description	25	Lowlands with variable land use, mainly arable
	26	Fertile lowlands with intensive agriculture
	27	Fertile lowland margins with mixed agriculture
Geography	25	N.E. Scotland
	26	Central and E. Scotland
	27	Central, E. and N.E. Scotland
Land Form	25	Alluvial, flood plains and morraines of glacial origin
	26	Valley floors, and coastal plains of glacial origin, sometimes with emergent outcrops
	27	Varied, but mainly valley floors and bluffs occasionally with ridges and scarps
Topography	25	Virtually flat, or gently rolling land mainly at low altitudes
	26	Undulating or smooth slopes mainly at low altitudes
	27	Variable, from mixtures of gentle and steep slopes to uniform moderate gradients; mainly at medium low or low altitudes
Landscape	25	Intensively farmed lowlands with fences and scattered farmhouses
	26	Rather mixed lowland landscapes, often affected by urban development
	27	Mainly well fenced lowlands, often mixed with woodland
Land Use	25	Mainly barley, but with much good grassland
	26	Mainly good grassland, but also much barley and pasture
	27	Arable, particularly barley, but also much pasture and good grassland
Soils	25	Brown earths, gleys and gleyed brown earths
	26	Brown earths and gleys
	27	Brown earths and gleys
Vegetation	25	Restricted to a few grassland types
	26	Limited, but mainly moorland types where present
	27	Restricted, but some grassland and moorland types

CURRICULUM CONNECTIONS

The simpler relationships engendered by altitude, aspect, slope, landform and relief are usually introduced at Standard Grade under key idea 4. The physical environment offers a range of possibilities for, and limitations on, human activities.

In Higher Still Intermediate 1 & 2 courses the focus is sharpened and the topics of either a) physical landscapes and land use, or b) landscapes and tourism are studied in the context of Scottish/ British glaciated uplands and upland limestone scenery.

In the Higher Geography Lithosphere Core, further progression requires an understanding of the development of regional landscapes (SNH material on the Cairngorms is helpful here), and the processes of slope formation. Two key skills required of students are

the identification, explanation and labelling of main landscape features on maps, aerial photographs and sketches, and
the construction and interpretation of cross-sections or transects.

Bunce, R.G.H., Barr, C.J. & Whittaker, H. (1981). A Stratification System for Ecological Sampling. In: Fuller, R.M. (Ed). Ecological Mapping from Ground, Air and Space. Institute of Terrestrial Ecology Symposium No. 10. ITE, Cambridge.
Benefield, C.B. & Bunce, R.G.H. (1982). A Preliminary Visual Presentation of Land Classes in Britain. Merlewood Research and Development Paper No. 91. Institute of Terrestrial Ecology, Cumbria.