Canadian Forest Service Publications
Urbanization and the loss of prime farmland: a case study in the Calgary-Edmonton corridor of Alberta. 2014. Martellozzo, F.; Ramankutty, N.; Hall, R.J.; Price, D.T.; Purdy, B.; Friedl, M.A. Regional Environmental Change 15(5):881-893.
Issued by: Northern Forestry Centre
Catalog ID: 35659
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Rapid urban expansion is a major contributor to environmental change in many parts of the world. This study investigated land cover changes that occurred between 1988 and 2010 in the Calgary–Edmonton corridor in Alberta, a region that has undergone considerable recent urban expansion. We used satellite imagery to develop land cover maps for four different snapshots in time between 1988 and 2010 and used these maps to investigate two principal questions related to urban expansion: (1) How did urban expansion affect other land cover types? and (2) How did urban expansion affect the availability of high-quality agricultural land in the region? Our results show that 60% of new urban and peri-urban growth between 1988 and 2010 occurred on agricultural land. Nevertheless, total agricultural land increased in the region because of the greater clearing of natural vegetation for agriculture away from the urban core. Urban expansion predominantly occurred on soils that were highly suitable for farming, while new agricultural expansion occurred on soils of poorer quality. As a result, the average soil quality of land used for agriculture has declined in the Calgary–Edmonton corridor, confirming other studies of the food security implications of urbanization.
Plain Language Summary
Over the past 25 years, economic and population growth due to the expansion of the oil and gas industry in Alberta have caused urban areas to increase in the Edmonton–Calgary region. Four satellite “snapshots from space” taken between 1988 and 2010 were used to map changes in land use. During this period, urban and suburban land use increased from ˜2.5% to ˜6.6% of total area, while agricultural land area increased from ˜31% to ˜34%, mainly at the expense of natural vegetation (woodlands and grasslands). Sixty per cent of urban expansion occurred on agricultural land, two thirds of which were highly suitable for farming. There has been a reduction in the average quality of agricultural land because converting the best land to urban and residential use has resulted in agricultural development on poorer quality soils. The rates of these conversions have generally accelerated during the 23 year study period. Based on projections of population growth in the region, we estimate urban areas could expand by a further 39–75% by 2036 (relative to 2010), causing the loss of 1000 to 2000 km2 of agricultural land, with much of this area occurring on the best soils.