Historic Distribution and Ecology of Tall-Grass Prairie in Western Canada

Rapid settlement and agricultural development of western Canada in the late 1800s and early 1900s nearly eliminated the tall-grass prairie, and pre-empted a detailed description by ecologists. A combination of literature review and historical ecological analysis of soils, climate, and composition data are applied to estimate the historic distribution, and area occupied by tall-grass prairie in southern Manitoba and southeastern Saskatchewan, Canada. The resulting area estimate of 20,830 km2 is more than three times any previously reported value. Some confusion of terms from the first half of the 1900s, and the impact of invasive species on vegetation patterns observed in the past 50 years, likely disguised the original distribution of tall-grass prairie. Protection and conservation efforts should now cast their nets wider to seek remnant prairies beyond the Red River valley, particularly westward along the Assiniboine, Qu’Appelle, and Souris rivers. Prospects are limited for managing these small fragments in a way that emulates the former natural disturbance regime of floods, fires, and bison grazing, but conservation and restoration efforts should continue.