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Prairies Ecozone+ Evidence for Key Findings Summary

Ecozone+ Basics

The Prairies Ecozone+, shown in Figure 1 and described in Table 1, is characterized by a semi-arid to sub-humid climate supporting vast, temperate grasslands. Most of the Ecozone+ was glaciated and consequently much of the land surface is made up of glacial deposits of varying thicknesses. The predominant land use is agriculture (Figure 2), of which the primary use is cultivation of annual crops, with areas of remaining native and tame grasslands used for livestock grazing and hayland. Small areas of forest remain, mainly in the Aspen Parkland Ecoregion. The Prairies are known for the many wetlands, or potholes, across the landscape. Figure 3 shows the seven ecoregions that comprise the Ecozone+.

Table 1. Prairies Ecozone+overview.
Area465,094 km2 (4.7% of Canada)
TopographyModest relief, from 200 m above sea level in the east to 1,200 m in the west.
Exceptions are the Cypress Hills on the Saskatchewan-Alberta border which rise almost 1,500 m above sea level and the Rocky Mountain foothills reaching 1,700 m above sea level. Part of the Great Plains.
ClimateVariable, with cool to very cold winters (average of -6 to -17oC), and warm, moist summers (average of 15 to 19oC).
Precipitation varies from less than 280 mm/yr in the dry core area to 540 mm/yr in the east, with high number of cloud-free days.
River basinsFalls within 14 sub-drainages of the Nelson River Drainage and a small part of the Mississippi River Drainage.
Major rivers include the North and South Saskatchewan, Bow, Red and Assiniboine.
GeologyDeposition directly from glacial ice creating rolling landscapes of medium-textured glacial till, with meltwater streams depositing sandy plains, and glacial lakes resulting in beds of clay soil.
Underlain by horizontally bedded sandstones and shales of Tertiary and Cretaceous age, with some Paleozoic limestone in the east.
SettlementTraditional territories for over a dozen Aboriginal groups.
European influence began with the fur trade in the 18th century, agricultural settlement beginning in the 19th century.
Major cities include Edmonton, Calgary, Regina, Saskatoon, Winnipeg, Brandon, and many other growing urban centres.
EconomyAgriculture, oil, natural gas, coal, and resource extraction such as potash.
Development83 large dams, primarily for irrigation.
Dense network of roads, both urban and rural; extensive network of drainage works in the east.
Extensive oil and gas development in some areas.
Potash and coal mining in some areas.
National/global significanceTwo national parks: Elk Island and Grasslands.
One biosphere reserve: Redberry Lake (SK).
Five Ramsar sites (wetlands of international significance): Beaverhill Lake, Quill Lakes, Last Mountain Lake, Delta Marsh, and Oak Hammocks Marsh.
Four Western Hemisphere Shorebird Network Reserve sites: Quill Lakes, Chaplin-Old Wives-Reed Lakes, Beaverhill Lake, and Last Mountain Lake.
Two World Heritage sites: Head-Smashed-In Buffalo Jump (Aboriginal hunting) and Dinosaur Provincial Park (dinosaur fossils).
Northernmost extension of Great Plains of North America and largest area of grassland in Canada.
Most altered of all the ecozones+ in Canada as a result of widespread conversion of natural grasslands to agriculture.
Remaining remnant grasslands support a unique assemblage of prairie species, including several species at risk.
Figure 2: Land cover of the Prairies Ecozone+, 2005
Graph
Source: Ahern et al., 2011Footnote7using data from Latifovic and Pouliot, 2005Footnote8
Long description for Figure 2:

This graphic presents a map and a stacked bar graph of the land cover of the Prairies Ecozone+ in 2005. The predominant land cover was agricultural land (88%), evenly distributed throughout the ecozone+. Grassland comprised 10% of the land cover and was located primarily in two large areas in the west-central and south-central parts of the ecozone+ along the Alberta–Saskatchewan border, although there were small patches of grassland scattered throughout. Both forest and shrubland each covered 1% of the ecozone+, scattered throughout but often found clustered together, and with larger areas found mostly in the southeastern part of the ecozone+.

Figure 3: Ecoregions of the Prairies Ecozone+.
Graph
Source: Ecological Stratification Working Group, 1995Footnote5
Long description for Figure 3:

This map shows the eight different ecoregions that make up the Prairies Ecozone+. The Cypress Uplands Ecoregion is the smallest ecoregion in the ecozone+ and encompasses the Cypress Hills area straddling the southern Alberta–Saskatchewan border. The Mixed Grassland Ecoregion surrounds the Cypress Uplands Ecoregion and includes Alberta's southeast corner and Saskatchewan's southwest corner south to the Canada-U.S. border. The Moist Mixed Grassland Ecoregion extends out from and surrounds the Mixed Grassland Ecoregion, forming a border around it. The Aspen Parkland Ecoregion extends out from and surrounds the Moist Mixed Grassland Ecoregion, forming much of the ecozone+'s western and northern boundaries and extending as far east as Manitoba. The Fescue Grassland Ecoregion is a small ecoregion located in southern Alberta, forming part of the ecozone+'s southwestern boundary and extending about halfway up the latitude of the ecozone+. The Lake Manitoba Plain Ecoregion is found entirely in Manitoba and encompasses Lake Manitoba and the Red River.  It forms the eastern boundary of the ecozone+. The Aspen Parkland and Southwest Manitoba Uplands ecoregions are very small ecoregions also located in Manitoba. The Aspen Parkland Ecoregion is located immediately west of Lake Manitoba and makes up a small section of the ecozone+'s northeastern boundary, while the Southwest Manitoba Uplands Ecoregion encompasses two small and roughly equally-sized patches, one of which is located on the Canada–U.S. border in southwestern Manitoba, and the other which is located equidistant between Brandon and Winnipeg.

One of the most striking facts about the Prairies Ecozone+ is the extent of landscape alteration and the speed with which it was altered. Natural vegetation, which covered essentially all of the ecozone+ in the late 19th century, was reduced to about 30% (and much less in some areas) by the late 20th century, largely due to the conversion of natural grassland to agriculture. Conversion appears to have levelled off in the last few decades but threats from growing cities, residential and industrial development, drainage projects, and agriculture continue. Remaining areas are becoming increasingly fragmented by cultivated fields, roads, and energy developments.
Most of the natural biodiversity of the ecozone+ is embedded in and supported by the natural vegetation.

Jurisdictions: The Prairies Ecozone+includes the southeast portion of Alberta (AB), the southern portion of Saskatchewan (SK), and the southwest portion of Manitoba (MB).

Population: The population of the Prairies Ecozone+ has been steadily increasing and reached 4.5 million in 2006 (figure 4). It has shifted from being predominately rural to predominately urban.

Figure 4: Human population in the Prairies Ecozone+, 1971–2006.
Graph
Source: Environment Canada, 2009Footnote9
Long description for Figure 4:

This bar graph shows the following information:

YearPopulation
19712,917,475
19763,122,528
19813,499,494
19863,681,926
19913,850,268
19963,979,522
20014,222,569
20064,514,106

 

Grasslands National Park, Saskatchewan
© istockphoto.com / 4loops
Grasslands National Park
Canola field, Manitoba
© istockphoto.com / graphicjackson
Canola Field
Example of closed-basin lakes
in southern Saskatchewan
© dreamstime.com / A. Nantel
Lakes

Northern Pintail
© istockphoto.com / J. Lugo (lugo)
Pintail

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Footnotes

Footnote 5

Ecological Stratification Working Group. 1995. A national ecological framework for Canada. Agriculture and Agri-Food Canada, Research Branch, Centre for Land and Biological Resources Research and Environment Canada, State of the Environment Directorate, Ecozone Analysis Branch. Ottawa, ON/Hull, QC. vii + 125 p. 

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Footnote 7

Ahern, F., Frisk, J., Latifovic, R. and Pouliot, D. 2011. Monitoring ecosystems remotely: a selection of trends measured from satellite observations of Canada. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 17. Canadian Councils of Resource Ministers. Ottawa, ON.

Return to footnote 7

Footnote 8

Latifovic, R. and Pouliot, D. 2005. Multitemporal land cover mapping for Canada: methodology and products. Canadian Journal of Remote Sensing 31:347-363.

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Footnote 9

Environment Canada. 2009. Unpublished analysis of population data by ecozone+ from: Statistics Canada Human Activity and the Environment Series, 1971-2006. Community profile data was used to make adjustments due to differences in the ecozone/ecozone+ boundary.

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