Merlewood computer 1971
A visit to Merlewood by Martin Holdgate (then Director of ITE) in May 1975 proved of pivotal importance in using the experience of the Cumbrian Survey (1974) to embark upon an Ecological Survey of Great Britain. After spending time in the field learning about the purpose and methods of the Cumbria Survey, Holdgate gave strong encouragement to the preparation of a national survey.
Working with the NERC Experimental Cartography Unit, automated data capture was used to abstract in digital form as many of the features as possible from the 1km2 squares of OS maps. Neither the air photographs nor satellite imagery then available provided sufficient detail or stability for classifying land cover or monitoring change. A 10 x 10km unit was rejected in favour of the 1km square, as a compromise between what it was practical to survey and what would allow complete coverage. Any analysis based on all the 234,000 1km squares covering the UK was beyond the computing power of the mid-1970s. A workable population of 1228 squares was produced.
Thirty-two land classes resulted from the analysis of the physiographic (eg. geology, soils, landform) and other mapped data. Strata from this classification were then used in the Ecological Survey of Great Britain to select 1km squares for field survey. A total of 256 1km square samples were selected at random from each of the original 32 land classes.
A field survey of land use, landscape and linear features, and cover type of each of the sample 1km squares was completed in 1978. Vegetation and soil data were also recorded from five random plots in each square, and a further six placed along linear features. The strata enabled the samples to be coordinated throughout the 32 land classes to produce estimates for the whole of the UK.
There was close agreement with the published estimates of the Forestry Commission for woodlands, and with the annual Agricultural Census of the Ministry of Agriculture, Fisheries and Food (MAFF). As well as confirming the value of such a sampling strategy, national estimates were produced for the first time of the area covered by the semi-natural classes of vegetation of the 79 land-cover categories adopted (Bunce & Heal 1984).
In the wake of this success, the resulting ITE Land Classification was further applied in developing a ‘rural land-use information system’ for the Scottish Highland Regional Council. The project was of seminal importance in developing a means of delivering environmental information and became the forerunner of the Countryside Information System (CIS).
Reference: J. Sheail & R.G.H. Bunce (2003) The development and scientific principles of an environmental classification for strategic ecological survey in the United Kingdom. Centre for Ecology and Hydrology.