Temperate Grassland Ecosystems

pampas grasslands Argentina Temperate grasslands are also known as prairie, puszta, pampas, plains or steppes with warm, moist summers (average 18ºC) and cool, dry winters (average 10ºC). It can snow during the winter. The most prominent temperate grasslands are found in the Great Plains of Canada and the United States, Argentina, South Africa, Central Eurasia and Australia.

There are two distinctive types of temperate grasslands – tall-grass (more than 2 meters) and short-grass less than 60 cm). Trees are generally not found in these regions due to the lack of moisture and their need for a relatively longer life cycle. Grasses such as purple needlegrass, blue grama, buffalo grass and galleta grow in the temperate grasslands.

Much of the temperate grasslands in North America have been converted into farmland and the once teeming herds of bison and pronghorn antelope have dwindled almost to extinction, except in regions where the prairie grasses have been retained. For example in Southern Saskatchewan province it is still possible to see wild pronghorn, and buffalo have been reintroduced into Grasslands National Park, the newest Canadian park located near Val Marie.

Steppes can be found in both Europe and North America where there are hot summers and cold winters, with an average rainfall of 25 – 50 cm. All too frequently the local peoples grow crops such as wheat and allow their livestock to graze, thus destroying the natural grasses.

Animal Adaptations

Physical Adaptations

The most predominant species found in the temperate grasslands are large grass-eating (herbivorous) ungulates (hoofed mammals), who are able to take full advantage of the various grasses found there and who have a specially adaptive digestive system to process the grasses. Because of the relatively short height of plants, they are able to see a predator from a distance and have adapted to be able to run swiftly away from danger.

Examples of animals that can be found in temperate grasslands of North America include bison, pronghorn antelope, rodents, badgers, coyotes, blackbirds, grouses, quails, hawks, owls, snakes, grasshoppers, leafhoppers and spiders. The Russian steppes are home to tarpan (wild horse), saiga antelope, polecats and mole rats, amongst others. The latter animal lives underground in burrows and is adapted to this lifestyle by virtue of their short limbs, small eyes, tiny external ears and large incisors used for digging.

Many grassland mammals have front legs and paws adapted to dig burrows where they can be safe from predators.

Camouflage

Many prairie animals have coats that blend in with the surrounding vegetation, so that they are camouflaged from predators. In the colder climates of Eurasia, the snow leopard has a coat of creamy white behind dark rosettes which helps to camouflage them in the snow and rocks.

Specialized Diets

Aardvarks eat only insects, utilizing their large claws to dig into anthills and termite mounds, and then utilizing their long, sticky tongues to lap up the insects.

Prairie dogs mostly eat grasses, seeds, leaves, flowers and fruit (herbivorous), but also eggs and insects.

Animals such as red-tailed hawks, owls, skunks, coyotes and opossums are carnivores (meat-eaters) and feast on small mammals.

Badgers are an example of an animal that eats both animals and plants (omnivores), choosing from a variety of rodents, frogs, snakes, insects, fruits and roots.

Nocturnal

The Australian dingo (wild dog) is an example of an animal that is active at night (nocturnal)

Interdependency

Despite many efforts to eradicate the black-tailed prairie dog because they were considered a nuisance to farmers, they still manage to survive in certain areas, living in burrows adjacent to one another in great numbers. These are known as “towns”. The highly endangered black-footed ferret depends upon the prairie dog as its sole source of food and, thanks to the efforts of several conservation groups, are now making a comeback in Wyoming and will soon be re-introduced into Grasslands National Park in Saskatchewan, Canada as the population of black tailed prairie dogs becomes stable.

Another example of interdependence is the monarch butterfly and the milkweed plant. The butterfly larvae eat the milkweed leaves (toxic to most other insects). This toxin accumulates in the butterfly’s body, making it inedible to most birds, and who consequently avoid the monarch.

Hibernation

As the weather turns cold, animals such as the thirteen-lined ground squirrel digs a deep nest below the frost line, plug the entrance with soil to keep themselves warm. In addition, these squirrels also build two other kinds of burrows – one for hiding for short periods of time and another to nest in during the warmer weather.

Plant Adaptations

The soil of the grasslands is generally deep and fertile, with roots penetrating way below ground where moisture is retained during droughts.

Perennial grasses bud below ground or just at the surface, making them resistant to drought, fire and cold. The stem is narrow and upright, reducing the affects of heat in the summer.

As with the tropical grasslands, the temperate grasslands also rely on seasonal drought, fire and grazing to prevent shrubs and trees from becoming established. Many beautiful wildflowers such as asters, coneflowers, goldenrods, sunflowers, clover, etc. thrive in these regions, as well as certain trees such as willow, oak and cottonwood near the rivers. Insects are attracted to the colourful blossoms of the wildflowers; as the insect feeds, the pollen brushes off on the insect who then carries it to another plant and in the process fertilizes that plant.

The stinging nettle plant has a beautiful plant but contains a painful sting to protect itself from humans and grazing animals.

Overgrazing and plowing over of grasslands lead to erosion of the soil during droughts. The loose soil left behind is picked up by strong winds, causing dust storms for miles and the loss of fertility in the earth.

Effects of Global Warming on Grasslands

One of the more dramatic effects of climate change on grasslands is an increase in the amount and frequency of rainfall which would encourage the growth of trees and other rainforest plants, thus destroying the balance of life in the tropical grasslands of the world. Along with the destruction of plants, many animals would not be able to compete or adapt to the new food supply and would become extinct.

A lowering in the quality of the grasses is also predicted because of a decline in soil carbon and nitrogen as a result of temperature and rising atmospheric carbon dioxide concentration.

Scientists also predict that the types of vegetation found in grasslands will change as a result of global warming. The most current dominant plant species in this ecosystem will die off and be replaced by foreign species, making the regions more susceptible to drought and grazing. This change could be catastrophic to the local animals who could possibly not be able to adapt to the new types of vegetation.

See also Tropical Grasslands

REFERENCES

Grassland Biome, Earth Observatory

http://earthobservatory.nasa.gov/experiments/nasa

The Grassland Biome, University of California Museum of Paleontology

http://www.ucmp.berkeley.edu/exhibits/biomes/grasslands.php

Grasslands, Missouri Botanical Gardens

http://www.mbgnet.net/sets/grasslnd/index/htm

Woodward, Susan L., Biomes of Earth, Terrestrial, Aquatic and Human-Dominated, Tropical Grasslands, Greenwood Press, 2003

Exploring the Environment

http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/savanna/savanna.html

Woodward, Susan L., Biomes of Earth, Terrestrial, Aquatic and Human-Dominated, Temperate Grassland’s Greenwood Press, 2003