The thesis demonstrates the application of historical cartographic and written sources to reconstruct land cover and climate conditions of the recent past for part of southern Manitoba, Canada, at a time just before the onset of intensive human land development for agriculture. Original Government of Canada Department of Interior Dominion Land Survey township maps and survey field notebooks from 1871 to 1877 are analyzed to reconstruct land cover. Historic land cover information is compiled in a Geographic Information System (GIS), quantified and mapped. Details on the historic distribution and extent of prairie grasslands, wetlands, forested areas and water bodies are captured in the GIS.

Tree ring data, instrumental measurements and newspaper accounts provide climate and other environmental information. Climate conditions just before and during the surveys are analyzed to identify relationships between land cover characteristics and temperature or precipitation patterns. Annual and seasonal land cover and climate variability are very apparent. Over the study period, precipitation variability and extreme events (severe storms and drought) produced the greatest impacts on land cover appearance, including influencing wetland distribution and extent, and the occurrence of grass and forest fires.

Comparisons are next made between the 19th century reconstructed pre-settlement land cover and 20th century land cover information from satellite-classifed imagery. The comparisons clearly show the extent of environmental change of the recent past. With settlement of the Canadian Prairies, dramatic, human-initiated changes to the landscape occurred with forest clearing and wetland drainage to accommodate agriculture. In the study area, in the 19th century, about 55% of the land cover is classified as grasslands; wetlands comprise at least 10%; and wooded areas about 35% of the landscape. In the 20th century, nearly all of the original grasslands have disappeared; wetland areas make up less than 1% of the area and about 9% of the land is treed. Although the Prairie landscape underwent dynamic and continuous changes caused by climate variability and change, and by impacts of large herds of grazing animals and fire, the human influences, especially over the last two centuries have contributed to rapid changes of land cover over a short period. These human-induced land cover changes are playing a role in influencing present-day and future regional climate patterns.