Historical Land Use and Ecosystem Health of the Canadian Semiarid Prairie Ecosystem

The Palliser Triangle is an area of about 500,000 km² in southwestern Saskatchewan and southeastern Alberta coinciding with the Mixe Grassland Ecoregion of the Prairie Ecozone and the Brown Soil Zone (Acton et al., 1998). The southern boundary of the Palliser Triangle corresponds with the international boundary at 49^°N latitude; however, ecological conditions of the land to the south in Montana and western North Dakota are similar. The Palliser Triangle was the focus of a major interdisciplinary study that examined the sustainability of the semiarid prairie ecosystem from the perspective of the health of the land and the well-being of the people, the Prairie Ecosystem Study (PECOS). The subject of this chapter is the history of land use and agriculture in the PECOS area, and the larger Palliser Triangle from the late 1800s until the present. It emphasizes the history of agricultural development, explores the difficulties that have periodically resulted in unhealthy ecosystems, and, finally, discusses today’s ecosystem health in relation to the past.