Protecting archaeological sites has become especially important in southern Ontario, where landscape change has been occurring at an ever increasing rate since 1950, resulting in substantial losses to the non-renewable archaeological record.
The scale of the threats facing the archaeological record of southern Ontario were considered in a study in which rates of demographic and agricultural change were examined over the last century, and estimates generated of the number of archaeological sites that have been destroyed. While the period of initial disturbance to sites was from 1826 to 1921, when large tracts of land were deforested and cultivated for the first time, that disturbance typically resulted in only partial destruction of archaeological data as most subsurface deposits remained intact. However, extraordinary population growth in the post-World War I period, resulted in a more disturbing trend as large amounts of cultivated land were consumed by urban growth.
Unprecedented population growth in the post-World War I period resulted in a dramatic decrease in the amount of cultivated land in Southwestern Ontario - the beginning of the cementing of the Ontario landscape.
In the process of this growth, it has been estimated that between 1951 and 1991, approximately 8,000 sites were destroyed in the Greater Toronto area alone.
Between 1951 and 1971, almost 2000 sites were destroyed in York Region.
Archaeological sites also face a less direct, but equally serious form of threat, in which human-made changes to the landscape inadvertently alter or intensify destructive natural processes in adjoining regions. Increased run-off of surface water in the wake of forest clearance, for example, or hydrological fluctuations associated with industrial and transportation developments, may result in intensified rates of erosion on certain sites due to processes such as inundation. The amount of land (and hence the potential number of archaeological sites) which has been subjected to these destructive forces is impossible to quantify, but is likely to be considerable.
While there has recently been a marked reduction in the rate of archaeological site destruction throughout much of the province, since certain municipalities adopted progressive planning policies concerning archaeological site conservation, the potential for the loss of archaeological resources in the future remains great, due to continuing growth and development.
Coleman and Williamson, 1994. Landscapes Past to Landscapes Future: Planning for Archaeological Resources, Great Lakes Archaeology and Paleoecology: Exploring Interdisciplinary Initiatives for the Nineties. Editor: Robert I. MacDonald. Quaternary Sciences Institute: University of Waterloo.