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 the United States, Canada 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, 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.
Grasslands are areas where the vegetation is dominated by grasses (Poaceae), however sedge (Cyperaceae) and rush (Juncaceae) families can also be found. Grasslands occur naturally on all continents except Antarctica. In temperate latitudes, such as northwestern Europe and the Great Plains and California in North America, native grasslands are dominated by perennial bunch grass species, whereas in warmer climates annual species form a greater component of the vegetation.
Grasslands are found in most ecoregions of the Earth. For example there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome ('ecosystem'), which is one of eight terrestrial ecozones of the Earth's surface.