EEB 337H - Families of Vascular Plants 

Grasslands: Ontario's Tallgrass Prairie - past and present

North American Grasslands (after USDA-FS Publ. 1548)

Grasslands of North America

This map is adapted from Ecoregions Map of North America by R. G. Bailey (1997; USDA-FS Miscellaneous Publication 1548), as prepared for display in the Tallgrass Prairie and Savannas alcove of the ROM's Hands-on Biodiversity Gallery (see below).

The region identified as "shortgrass prairie" actually comprises two ecoregions, the dry steppe of the Palouse region of eastern Washington (not shown) and the great plains (shown here; western portion), together with the great plains steppe (eastern portion). These regions lie in the rain shadows of the Cascades and the Rocky Mountains, respectively, and so receive 260-640 mm of precipitation annually (compare this with the precipitation in the deciduous forest, which is 890-1,530 mm).

Further east annual precipitation increases to 510-1,020 mm, and this makes possible grasslands that are richer in forbs and interspersed with islands of forest (tallgrass prairie). Still further east, in the deciduous forest, islands of tallgrass prairie occur wherever local conditions such as vernal flooding and summer drought make the growth of trees difficult. Burning, as a result of either lightning strikes or human activity, further hampers tree growth and promotes prairie vegetation.

Map © 2002 Royal Ontario Museum.

 

 

Ontario's Tallgrass Prairie

Ontario tallgrass prairie prior to European settlement (estimate)

Prior to European settlement, it has been estimated that tallgrass prairies and savannas were distributed as shown in red on the map at the left.

This map, and the map below are based on maps compiled by W. Bakowsky of the Natural Heritage Information Center of the Ontario Ministry of natural Resources. They were prepared for display in the Tallgrass Prairie and Savannas alcove of the ROM's Hands-on Biodiversity Gallery (see below).

Map © 2002 Royal Ontario Museum.

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Ontario tallgrass prairie sites today

Click HERE to read an illustrated student essay on the tallgrass prairies of Ontario.

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Tallgrass Prairie & Savannas alcove, ROM Hands-on Biodiversity Gallery

Today, tallgrass prairie and savanna are Ontario's most threatened habitats. Never very abundant in Ontario, these habitats are now restricted to the sites shown in red on the map at the left. The Tallgrass Prairie and Savannas alcove of the ROM's Hands-on Biodiversity Gallery (above) documents the unique features of these habitats, and the plants and animals that are make use of them. Click HERE for more information about the plants of Ontario's tallgrass prairies and savannas.

Photo: T. A. Dickinson. Map and photo © 2002 Royal Ontario Museum.

 

 

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Please send your comments to tim.dickinson@utoronto.ca; last updated 29-Sep-2008