Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the pampas of Argentina, Brazil and Uruguay as well as the steppes of Eurasia. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the area referred to as the Interior Lowlands of Canada, the United States, and Mexico, which includes all of the Great Plains as well as the wetter, somewhat hillier land to the east. In the U.S., the area is constituted by most or all of the states of North Dakota, South Dakota, Nebraska, Kansas, and Oklahoma, and sizable parts of the states of Montana, Wyoming, Colorado, New Mexico, Texas, Missouri, Iowa, Illinois, Ohio, Indiana, Wisconsin, and western and southern Minnesota. The Central Valley of California is also a prairie. The Canadian Prairies occupy vast areas of Manitoba, Saskatchewan, and Alberta.
The Prairies Ecozone is a Canadian terrestrial ecozone which spans the southern areas of the Prairie provinces of Alberta, Saskatchewan, and Manitoba. It is a productive agricultural area, and is commonly referred to as "Canada's breadbasket". Farmland covers about 94% of the land, and is the dominant domestic economic activity of the zone, as well as an important factor in Canadian foreign trade.Natural gas and oil are abundant in the area. The corresponding Level II ecoregion of the US Environmental Protection Agency is the Great Plains Ecoregion.
Despite the predominance of farming, less than 10% of the population is involved in agriculture. It is a highly urbanized area, with all major population centres of these provinces located in this ecozone. These include Edmonton, Calgary, Regina, Saskatoon and Winnipeg, as well as Brandon, Moose Jaw, Red Deer and Lethbridge. Nearly 80% of the region's four million inhabitants live in these and other urban areas.
Following Alberta's border with British Columbia, this ecozone is adjacent to the Montane Cordillera on the west. The two zones are bifurcated by the Boreal Plains about 70 kilometres southwest of Calgary, which also wraps around the remaining extent of the zone north of the United States border toward the Red River Valley. It is part of the Interior Plains, the Canadian extension of the Great Plains, and covers approximately 520,000 square kilometres of land and water.