Patterns in archaelogical monument loss in East Central Scotland since 1850

Abstract

The Monuments at Risk Survey 1995 (MARS) outlined rates and causes of identified monument loss in England, showing that 16% of recorded monuments had been completely destroyed by 1995, and that 95% of surviving monuments in England had suffered partial destruction. Hitherto, no equivalent research has been undertaken in Scotland. Using a 17% random stratified sample of 779 field monuments surviving in 1850 within a study area encompassing much of the local authority areas of Perth and Kinross, Fife and Angus, the present research has analysed the distribution and quantified loss of archaeological monuments since 1850 in relation to a number of variables including land use, Land Capability for Agriculture, elevation, local authority area, monument period and material construction. Results show that monument distribution within the study area varies most noticeably according to land use and elevation. The highest densities of extant monuments are found in semi-natural woodland (17.2 extant sample monuments per 100km2) and non-intensive land uses such as unimproved grazing and moorland (13.8 extant sample monuments per 100km2). The lowest density of extant monuments is found in arable and improved pasture (4.5 extant sample monuments per 100km2), although this is offset by a recorded density of 11.5 cropmark sample monuments per 100km2. By elevation, monument densities are highest below 100m OD (24.4 monuments per 100km2) and between 250m OD and 400m OD (21 monuments per 100 km2)with a pronounced paucity of recorded monuments between 100m OD and 200m OD, particularly on improved and arable land. For each sample monument, a condition history has been constructed through a desk-based study using data from the National Monuments Record of Scotland. This desk-based study has recorded the greatest causes of monument loss since 1850 as unknown causes (28% of loss), archaeological excavation (24% of loss), farming (15% of loss) and development (11% of loss). The monument condition histories created through the desk-based study have then been augmented and calibrated for a subsample of 258 monuments by means of an accuracy assessment, using information from vertical and oblique aerial photographs, survey reports from Historic Scotland Monument Wardens and a programme of field survey. Using these additional data sources, the accuracy assessment has identified the largest causes of monument loss within the study area since 1850 as forestry (31% of loss), farming (28% of loss) and development (12% of loss). Analysis shows that among monuments extant in 1850, a minimum of 38% have been reduced in extent, with at least 5% destroyed. Loss has been greatest among monuments found in arable and improved land (39% reduced, 27% destroyed), forestry (79% reduced, 9% destroyed) and developed land (63% reduced, 27% destroyed), and lowest among monuments found in permanent pasture (91% undamaged), semi-natural woodland (75% undamaged) and rough grazing and moorland (85% undamaged). Although the use of a desk-based study and accuracy assessment has proved successful in identifying trends in the loss of visible monuments, it has been necessary to employ alternative methods by which to assess damage at buried monuments represented by cropmarks. To this end, a programme of excavation, topographic survey and soil depth recording has been undertaken at five locations in Perth and Kinross. Analysis of the results from this programme of excavation and survey has identified statistically significant relationships between land surface curvature and topsoil depth at three of the five sites examined, enabling the mapping at site scale of areas which are likely to have been subject to greatest agricultural damage. Extrapolating from these site-specific maps, it has been possible to map probable damage and risk to cropmark monuments at a regional scale. Although the validity of this regional scale mapping has been limited by the 25m cell size of the digital terrain model on which it has been based, the potential of such a technique in enabling a rapid preliminary assessment of damage and risk to cropmark monuments has been demonstrated.