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Manitoba's Tall Grass Prairie Preserve

THE MIXED-GRASS PRAIRIE

A vast expanse of grassland once stretched across the Canadian prairie provinces. Short-grass prairie, the most drought tolerant, was found in the rain shadow of the Rockies. In the moisture rich Red River Valley of Manitoba, a lush carpet of grasses and wildflowers grew in the tall-grass prairie. Mixed-grass prairie lay between the two prairie types, blending elements of both short-grass and tall-grass prairie. Here, the wildflowers and grasses grew to knee height and huge herds of bison roamed the plains.


Range of the mixed-grass prairie.

The beauty and resilience of the mixed-grass prairie lies in its incredible diversity of species. There are over 150 species of plants, each adapted in its own way to the extremes of temperature, variation in precipitation and the effects of fire and grazing animals. Local topography, the nature of the soil, and year-to-year changes in moisture and temperature help determine the mix of plants found in a particular prairie. In areas with well drained soils, drought tolerant grasses such as western wheatgrass and blue grama may grow, but within metres, little bluestem, a grass requiring more moisture, will dominate.

All animals, from voles and ground squirrels to large grazers like bison play a role in the development and composition of a prairie. Any disturbed ground - along an animal trail, beside a burrow or in a bison wallow - can encourage plants that complete their life cycles in one season, to sprout, holding the soil until the longer living grasses and wildflowers establish themselves.

Numerous combinations of moisture, topography, soil and disturbance exist making every prairie unique and dynamic in its species and appearance. In Manitoba, mixed-grass prairie occurs in areas receiving between 25 cm and 50 cm (10"-20") of precipitation annually. Its occurrence is also determined by the presence of soils that are sandy or well-drained. Remnants of mixed-grass prairies are often found inter-mingled with aspen stands and other grassland communities.

Mixed-grass prairie and many of its plants and animals have been and continue to be lost. As early as the 1860's, settlers were having dramatic long term effects on the prairies. By the 1880's plains bison, plains wolves and passenger pigeons had been eliminated and many other plants and animals were diminishing rapidly. The prairie itself was being lost as homesteaders broke the sod to grow crops. The introduction of exotic or weed species, such as leafy spurge and Canada thistle, and the invasion of native shrubs and trees, led to the degradation of thousands of hectares more. It is estimated that there were originally 24 million hectares of mixed-grass prairie in Canada. Today it covers less than one quarter of that area.

PLANTS OF THE MIXED-GRASS PRAIRIE

Prairie plants are perfectly adapted to their environment. Many have extensive roots systems that are ideal for absorbing moisture and nutrients from the soil during periods of low moisture. These root reserves are important for regrowth after grazing or burning. Some plants, cool-season plants, begin their growth early in the season to take advantage of the early spring moisture and stop growth in the heat of the summer. Other plants called warm-season plants have adapted to the hot summers and low moisture levels by changing the way they produce food in their leaves and stems. Their unique metabolism allows them to grow during hot, dry weather without losing precious moisture.

At first glance, mixed-grass prairie may simply look like a field of unmown grass, but a closer look reveals the complexities and subtle enchantment of this prairie world. Some of the typical wildflowers and grasses you may find when you visit mixed-grass prairie are illustrated here.

 

Spear grass
(Stipa comata)

The slender pointed fruits of spear grass have long twisted "beards" or awns projecting from their tips. After the seed is shed, the first moisture causes the awn to straighten. Then, in drying out, it twists again and screws the seed into the soil, where it can germinate. These "spears" are often found embedded in the pant legs and shoe laces of visitors.

Indian breadroot
(Psoralea esculenta)

Indian breadroot has a thick tuberous root, once valued as a food source by Aboriginals and early settlers. This plant is very sensitive to disturbance; the presence of Indian breadroot usually indicates a healthy prairie.

Purple prairie clover
(Petalostemon purpureus)

Both purple prairie clover and a close relative, white prairie clover, are important in prairie communities. These plants are members of the pea family which fix nitrogen and make it available to other plants. The small flowers begin as a circle around the head and work upward as the season advances.

Prairie crocus
(Anemone patens)

A sign of spring in North American prairies and Manitoba's floral emblem, the crocus often blooms shortly after the snow disappears. Its many-divided, silky leaves arise after flowering is completed.

 

Dotted blazing star
(Liatris punctata)

Blazing star and its close relatives were once used by Native Americans to treat kidney diseases and have long been cultivated in European gardens as bedding plants and for cut flowers.

 

 

June grass
(Koeleria gracilis)

Common throughout mixed-grass prairies, this grass begins its growth in early spring. By July, growth of this cool season plant is completed and the grass goes dormant until fall or the following spring. It is commonly found along trails in mixed-grass prairie.

Blue grama
(Bouteloua gracilis)

Blue grama is easily recognized by its seed head that resembles a toothbrush. This warm season grass is very drought hardy and will out compete taller grasses in times of low moisture.

Little bluestem
(Schizachyrium scoparium)

This vigorous, long-lived warm season species is found throughout mixed-grass prairies in Canada and the United States. It is highly palatable and nutritious for livestock and wildlife. In autumn, little bluestem turns the prairies a beautiful reddish purple.

Purple coneflower
(Echinacea angustifolia)

The prickly centre of the purple coneflower gives this plant its scientific name - Echinacea - from the Greek word meaning hedgehog or sea-urchin. The root was used by Aboriginals as a painkiller for toothaches and sore throats.

THREATENED AND ENDANGERED SPECIES IN MIXED-GRASS PRAIRIE

Manitoba's Endangered Species Act (1990) protects plant and animal species that are considered endangered or threatened within Manitoba. Under the Act, native species threatened with extinction are classified as "endangered". Native species likely to become endangered or found in low numbers are classified as "threatened". A species is considered "vulnerable" if it is found in low numbers or restricted areas but is not yet threatened. Vulnerable species are not protected under the Act. The following mixed-grass prairie species are recognized and protected as endangered or threatened in Manitoba.

Small white lady's slipper (Cypripedium candidum)

The small white lady's slipper is an endangered orchid found in wet meadows in fewer than 10 locations in southern Manitoba. It grows in clumps, blooming briefly in late May or early June. Like many orchids, the small white lady's slipper cannot reproduce without the presence of a companion fungus, nor can the mature plants live without a symbiotic fungus found within its root system. It is unlawful to pick, dig or disturb the surroundings of this plant.

Burrowing Owl
(Athene cunicularia)

The Burrowing Owl prefers grazed pastures or mixed grass prairie. Unlike any other North American owl, it nests below ground, occupying abandoned ground-squirrel burrows. Once common to the grasslands of western Canada, the Burrowing Owl can no longer be found in large portions of its historic range. In Manitoba, the known nesting population had dwindled to four pairs by 1995. The loss of nesting habitat and the poisoning of owls by insecticides intended to control grasshoppers have contributed to their decline.

Ferruginous Hawk
(Buteo regalis)

The largest North American hawk, the Ferruginous Hawk is often seen soaring above the open grasslands searching for ground-squirrels. Ferruginous hawks usually nest in isolated trees, building large flat nests. A breeding pair of Ferruginous Hawks and their young will eat almost 500 ground-squirrels during a nesting season. After a suspected absence of some 50 years, Ferruginous Hawks were found nesting in southwestern Manitoba in 1982. Since then, the nesting population has grown to about 50 pairs.

Loggerhead Shrike
(Lanius ludovicanus)

The Loggerhead Shrike lives primarily in open shrubby country and dry upland prairie. The shrike is known for its practice of impaling its food (grasshoppers, insects or rodents) on thorns and barbed wire. Loss of grasslands and shrub lands, combined with the accumulation of pesticides in the food chain are the main reasons for their decline.

Baird's Sparrow
(Ammodramus bairdii)

The Baird's Sparrow is well camouflaged to blend into its prairie environment. It can be difficult to find, but its call, two to three zips followed by a musical trill, is distinctive. It nests on the ground in idle or lightly grazed native mixed-grass prairie. Formerly common throughout southern Manitoba, they are now restricted to the southwest corner of the province.
Baird's Sparrow

MANAGEMENT

The natural forces of fire and grazing helped shape and form mixed-grass prairie. The extensive root reserves of native plants allow them to regrow quickly after grazing or burning occurs. In order to maintain good quality native mixed-grass prairie, rotational grazing and occasional controlled burning must continue to be used. Excessive grazing can eliminate or suppress many species. However, the absence of grazing can increase woody growth and lead to a build up of plant litter, choking out some native species. Haying or mowing can also decrease woody species when burning or grazing are not possible.

 

How often a prairie should be burned depends on the purpose of the burn and local moisture conditions. Properly timed burns can help decrease woody growth and the presence of weedy species. Annual burns on mixed-grass prairie can be destructive over the long term, lowering moisture levels and destroying organic matter in the soil. Each prairie should be treated individually, according to the plant species present and the surrounding land use.

WHY SAVE IT?

The reasons to save native mixed-grass prairies are many and varied. It is home to wide variety of plants and animals, some that are commonplace and others that are rare. Species like sharp-tailed grouse and deer are frequently observed but some, such as the small white lady's slipper and burrowing owl, are seen only by a lucky few. Native prairies and the species in them are often useful, economically and scientifically. No one knows what value prairie species may hold for future crops, medicines and other products. Native mixed-grass prairie is a living museum brimming with beauty and untapped information, a rich natural heritage for all Manitobans.

NatureNorth.com would like to thank the Critical Wildlife Habitat Program and the Wildlife Branch, Manitoba Natural Resources for permission to reproduce this "Manitoba's Mixed Grass Prairie" brochure.

For more information please contact:

Critical Wildlife Habitat Program
Box 24 200 Saulteaux Cres.
Winnipeg, Manitoba
CANADA
R3J 3W3
(204) 945-7775

Thanks for learning about Manitoba's Mixed-grass Prairie! Bye for now!
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