Saskatchewan’s ecoregions

I’m in the middle of a tour of 60-some schools with Prairie Opera, and aside from the enjoyment of performing, the best thing about the tour is the opportunity to see so much of Saskatchewan. One thing quickly impresses itself: there’s a lot more to this province than a flat, treeless plain, even if that’s how most of us who live in the south tend to think of it.

Saskatchewan is actually divided into six distinct “ecoregions,” determined by the interactions among the climate, the landscape, and the plants and animals that live there.

The landscape, obviously, came first. Saskatchewan’s current landscape ranges from rolling hills to table-flat prairie to the rocks and lakes of the north. It got this way over approximately 4.6 billion years (the estimated age of the Earth), although we only have a geological record of the last 3.1 billion or so. During those eons, what would eventually be Saskatchewan passed through five major stages.

At first it was mostly underwater, until a series of volcanic islands formed. These eventually became mountains, which eroded away to shallow, tropical seas: seas which covered the province for much of the time from 1.7 billion to 65 million years ago. (At the time, Saskatchewan was down around the equator; by the age of the dinosaurs, continental drift had brought it to just about its present location–more’s the pity.)

Toward the end of that period, the seas retreated, leaving forested land. From about 50 million years ago until the beginnings of the Ice Age about two million years ago, Saskatchewan’s climate changed, and forests gave way to grassland.

Then came the glaciers. At least five huge sheets of ice have scoured the province and then melted away, and these, more than anything else, shaped today’s landscape–especially the last, which scraped across Saskatchewan between 17,000 and 10,000 years ago.

In the north, where the Canadian Shield (which contains rocks billions of years old and valuable mineral deposits) lies close to the surface, the last glaciation produced myriad lakes, as boulders trapped beneath the glaciers gouged out areas of softer rock. When the glaciers retreated, the resulting depressions filled with water.

In the south, the retreating glacier produced a huge lake of meltwater, Lake Agassiz, that at one time stretched from Prince Albert to Lake Superior. Sediment from that lake gave us the vast, flat plains of the southeast.

Meltwater also carved valleys, such as the Frenchman River Valley and the Qu’appelle Valley. Glaciers also left behind gravelly hills as they melted, and created the knobby “prairie pothole” terrain, which formed when blocks of ice calved off the retreating glacier and were buried in the other debris the melting glacier left behind. When the buried blocks finally melted, the rocks and soil piled on top of them collapsed, leaving behind potholes. Today these potholes, which fill with water each spring when the snow melts, are the major breeding habitat for waterfowl.

Black spruce forest quickly spread across the landscape vacated by the ice, but drying conditions soon converted the southern portion of the forest to prairie. (Between 7,500 and 6,000 the prairie actually extended much further north than it does now; the forest pushed its way southward again about 3,000 years ago.)

Today, the prairie’s ecoregions are defined as sub-arctic boreal (the extreme northeast), northern boreal (from the extreme northwest roughly down to LaRonge), southern boreal (LaRonge south to Prince Albert in the central part of the province, further south in the east), parkland (Prince Albert to just north of Saskatoon in the centre and clear down to the Qu’Appelle River in the east), Cypress Hills, and grassland (everything else).

Climate is the most important element of an ecoregion. All of Saskatchewan shares two of the characteristics of temperate central continental climates: long, cold winters (in case you haven’t noticed) and short, warm summers. But there’s considerable difference between the climates of northern and southern Saskatchewan, just the same.

In the subarctic boreal region, north of Wollaston Lake, the mean daily January temperature is only -27.4 degrees Celsius, the coldest in the province, while the mean July daily temperature is only 15 degrees. However, it’s quite moist. These factors, combined with poor, shallow soils, combine to produce a rather sparse forest made up primarily of black spruce.

The northern boreal region, though still cold, is a couple of degrees warmer than the subarctic region. It’s even moister than the subarctic region, but it still has the problem of poor, shallow soils. The forest consists primarily of jack pine in upland areas and black spruce in boggy areas.

The southern boreal region (which is as far as I’ve penetrated in my touring) is dryer and warmer, though still wetter and colder than the south. This, combined with somewhat better soils, allows a wider variety of trees to grow: not just black spruce and jack pine, but also white spruce, aspen and balsam poplar.

The parkland region gets its name from the fact that it looks like a park, with broad open spaces, originally covered mostly with bluegrass, interspersed with groves of trees, mostly aspen and bur oak. This is due to its relatively dry, warm climate and richer soils.

Even dryer and warmer, the grasslands don’t support trees at all, except in special circumstances (along river beds, for example). Nowadays, the grasslands are mostly covered with farms, but originally, speargrass was the predominant species, growing lushly in the rich sediments left behind by Lake Agassiz.

Cypress Hills is an ecoregion all to itself because it’s completely different from anything else in the province. The ecoregion’s altitude has had two effects: it protected the local ecosystem from glaciation (the Cypress Hills plateau was the only part of Saskatchewan not covered with ice) and it produces a moist, cool climate more like that of the southern boreal forest than that of the surrounding prairie, the driest, warmest part of Saskatchewan. Cypress Hills is the only place in the province where you find the lodgepole pine forests typical of the Rockies.

So as you can see, there’s a lot more to Saskatchewan than whatever landscape you can see out your living room window. At the risk of sounding like a tourism brochure, this summer, why not visit Saskatchewan?

You don’t have to be on an opera tour to have a good excuse.

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