Information and Advisory Note Number 124 Back to menu
1.1 Semi-natural habitats that are especially distinctive in Scotland are rough
grassland, heather moorland, blanket mire, lowland mire, broadleaved woodland,
mixed woodland, coniferous woodland, lochs, bracken and scrub. Few have been
unaltered by human activities over the course of history. Some, such as rough
grassland and heather moorland, rely on active land management of grazing and
moorland burning to suppress tree regeneration below the natural treeline. The
term 'semi-natural' is therefore used to describe vegetation communities that,
albeit in an altered state, sustain Scotland's native plants and animals.
1.2 The general trend, from the late 1940s to the late 1980s, has been a
contraction of semi-natural habitats. Notable have been the effects of
• urban development;
• agricultural intensification in arable and lowland grassland production
systems; and
• the utilisation of the uplands for water catchment, farming and forestry.
There, the expansion of conifer forest has been particularly distinctive.
2.1 Over 41 years, between c.1947, c.1973 and c.1988, the area of semi-natural
land cover in Scotland is estimated to have declined by 17%; a mean annual rate
of 230 km².
2.2 Four-fifths of the decline (81 %) between the 1940s and the 1980s was due to
afforestation, which affected open habitats as well as semi-natural woodland.
Pasture improvement accounted for most of the remainder (13%).
2.3 Reservoir construction, particularly in the Highlands, flooded former lochs
as well as rough grassland and heather moorland.
2.4 Although built development took place mainly in the more fertile and
intensively farmed lowlands, built-up areas and roads also encroached onto
semi-natural habitats of blanket mire, rough grassland, heather moorland.
2.5 Afforestation, grassland improvement and urban development took place
throughout much of Scotland between the 1940s and the 1980s. The biggest
reductions in semi-natural cover were in the south and parts of the west, where
afforestation was especially intensive.
2.6 In contrast, in the Western Isles, where land capability for forestry and
agriculture is highly restricted, relatively little change took place.
2.7 The extent of semi-natural features contracted from around 56,000 km2 (72%
of Scotland) in the 1940s to 46,500 km2 (60% of Scotland) in the 1980s.
3.1 Statistical estimates are from the 'National Countryside Monitoring Scheme',
a sample survey which interpreted air-photography representing 7.5% of
Scotland's land area (Mackey et a/., 1998). Although sampling is not optimal for
this purpose, change in extent is mapped here according to the 21 Natural
Heritage Zones.
3.2 The geographical distribution of habitats was mapped using the nearest
equivalent features from the Land Cover of Scotland 1988 dataset (MLURI, 1993).
Macaulay Land Use Research Institute (1993). The Land Cover of Scotland 1998:
Final Report. Aberdeen: MLURI.
Mackey, E.C., Shewry, M.C. and Tudor, G.J. (1998). Land Cover Change: Scotland
from the 1940s to the 1980s. Edinburgh: The Stationery Office.
Further information on other topics covered by Natural Heritage Trends: Land Cover 1947-1988 can be found in Information & Advisory Note No. 123.
To obtain further information about any of the issues raised in this l&A Note,
please contact
Mr Ed Mackey and Mr Mike Shewry
Environmental Audit Group
Chief Scientist's Unit
Scottish Natural Heritage
2 Anderson Place
Edinburgh EH6 5NP
Tel: 0131-446 2415
Fax:0131-446 2405
E-mail: ed.mackey@snh.gov.uk