Grasslands

1. Grasslands By Mira Mooreville and Dana Gitlin

2. What is a grassland? • Regions with enough average annual precipitation to allow grass to prosper but with precipitation so erratic that drought and fire prevent large stands of trees from growing.

3. Where are Grasslands? Grasslands can be found on all continents except Antarctica.

4. Climatogram

5. Three Main Types of Grasslands • Tropical • Temperate • Polar (tundra)

6. Tropical Grasslands • Found in areas with high average temperatures, low to moderate precipitation, and a prolonged dry season. • They are widely spread on either side of the equator beyond the borders of tropical rain forests. • A type of tropical grassland is a savanna.

7. Savannas • Have warm temperatures year round, two prolonged dry seasons, and abundant rain the rest of the year. • Largest Savannas are found in central and southern Africa, but can also be found in Central South America, Australia, and Southeast Asia.

8. Savanna Species • Common Savanna animal species include wildebeests, gazelles, zebras, giraffes, antelopes, cheetahs, lions, hyenas, eagles, and hawks. • Many large Savanna animal species are killed for their economically valuable coats and parts (tigers), tusks (rhinoceroses), and ivory tusks (elephants). • Some Savanna plant species include Bermuda grass, candelabra tree, elephant grass, gum tree eucalyptus, whistling thorn, and river bush willow.

9. Temperate Grasslands • Cover vast expanses of plains and gently rolling hills in the interiors of North and South America, Europe, and Asia. • Winters are bitterly cold, summers are hot and dry, and annual precipitation is fairly sparse and falls unevenly through the year. • Types of temperate grasslands are the tall-grass prairies and short-grass prairies of the midwestern and western US and Canada, South American pampas, African veldt, and steppes of central Europe and Asia. Prairie

10. Prairie Species • Common prairie animal species include the American Bald Eagle, bobcat, bumble bee, coyote, prairie dog, and swift fox. • Some prairie plant species include big bluestem grass, blue grama grass, buffalo grass, milkweed, and stinging nettle.

11. Food Web (Prairie)

12. Symbiotic Relationship • Certain types of ants and aphids have a relationship known as mutualism, a type of symbiosis, in which species help each other to survive. Aphids, tiny slow-moving insects, live on plants. They feed on nectar, which they suck out of plant stems with their long, pointed mouths. As the aphids digest the nectar, it is formed into a sugary substance called honeydew. The aphids then release honeydew through specialized organs called cornicles. Honeydew is one of the ants favorite food. The ants eat as much honeydew as the aphids can produce. The ants treat the aphids like their own private heard. By keeping the aphids close to them at all times, ants have a natural food supply.

13. Abiotic Factors of Grasslands • Soil • Sunlight • Water • Rocks • Air

14. Soil • Aboveground parts of most of the grasses die and decompose each year, allowing organic matter to accumulate and produce a deep, fertile soil. The soil is held in place by a thick network of intertwined roots of drought-tolerant grasses. • Because of their thick and fertile soils, temperate grasslands are plowed up and widely used to grow crops. • The plowing however breaks up the soil leaving it vulnerable to erosion by wind and water.

15. Major Human Impacts on Grasslands • Conversion of savanna and temperate grassland to cropland. • Release of carbon dioxide to atmosphere from burning and conversion of grassland to cropland. • Overgrazing of tropical and temperate grasslands by livestock.

16. Example of a Human Impact • Indian tribes and wildlife used to settle on the vast grasslands of the Great Plains in the United States. The settlers brought cattle and sheep which grazed the plains. Settlers farmed the land and plowed the topsoil. But in the 1930’s, there was an eight-year drought which brought major wind and dust storms. As a result, the soil became dry and loose and crops could not grow. Because humans allowed the natural grassland ecosystems to be overgrazed and improperly utilized, the land was unable to endure such a long drought. The government set up regulations to help the farmers restore the land. The Dust Bowl.

17. Environmental Damage and Solutions • Grasslands are adapted to high levels of animal impact by herds of animals. Animal impact includes dunging, urinating, trampling, rubbing, wallowing, salivating, etc. Their trampling and dunging is extremely beneficial to the land and has maintained the grasslands for millions of years. The beneficial effects of animal impact exist only on high impact for a short duration. Low impact for a long duration leads to environmental damage because plants and soils do not get a chance to recover and restore itself, therefore becoming overgrazed. • Animal impact maintains grasslands by: • Planting seeds and guaranteeing good seed-to-soil contact • Breaking soil crusts that obstruct the process of seed germination and rainfall absorption • Pruning plants to keep them fertile and active • Eliminating weeds • Mulching the soil surface with trampled vegetation, which protects it from erosion and reduces soil surface evaporation • Composting plant material • Fertilizing the soil

18. Environmental Damage and Solutions (cont’d) • If grasslands do not have any animal impact, they will deteriorate, especially in very dry areas. When grazing animals leave an ecosystem, damage to the land will occur. Example: Nevada used to be a grassland 100 years ago, but today it is mostly an arid desert. • Animal impact is the most effective way known to renew the damaged land and deserts. • Today, animal impact is used worldwide to: • Help vegetation in mine dumps in Nevada and Arizona, U.S.A. • Restore desertified grasslands in South Africa, Zimbabwe, and the western U.S. • Control invasive weeds in South Africa, Oregon and Montana. • Repair erosion damage in Mexico and California. • Prevent soil-surface erosion in Australia • Build new topsoil at rates of up to 1" per year • Increase the ability of soil to absorb water in Australia, Africa, and New Mexico. • Encourage biodiversity in Australia, Africa and the western US.

19. Citations • Textbook • http://images.google.com/imgres?imgurl=http://www.deepcreektimes.com/kids/world_grasslands_map.jpg&imgrefurl=http://www.deepcreektimes.com/kids/september2004.html&h=314&w=580&sz=15&hl=en&start=2&tbnid=dQ_3jb7w_rTBxM:&tbnh=73&tbnw=134&prev=/images%3Fq%3Dmap%2Bworld%2Bgrassland%26svnum%3D10%26hl%3Den%26lr%3D • http://images.google.com/imgres?imgurl=http://www.fws.gov/midwest/EcosystemConservation/savanna.jpg&imgrefurl=http://www.fws.gov/midwest/EcosystemConservation/savanna.html&h=335&w=250&sz=16&hl=en&start=26&tbnid=_4zwVeRyFoz-JM:&tbnh=119&tbnw=89&prev=/images%3Fq%3Dsavanna%2B%26start%3D20%26ndsp%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN • http://www.larry-bolch.com/Alberta-Skies/images/Prairie-01.jpg • http://www.blueplanetbiomes.org/prairie.htm • http://www.blueplanetbiomes.org/savanna.htm • http://images.google.com/imgres?imgurl=http://www.kazakhstanbirdtours.com/images/steppe%2520grassland.jpg&imgrefurl=http://www.kazakhstanbirdtours.com/steppe.htm&h=375&w=500&sz=30&hl=en&start=9&tbnid=kMQ-3xrRlP0jNM:&tbnh=98&tbnw=130&prev=/images%3Fq%3Dgrassland%26svnum%3D10%26hl%3Den%26lr%3D • http://images.google.com/imgres?imgurl=http://www.stripedmouse.com/images/grassland.jpg&imgrefurl=http://www.stripedmouse.com/site1_1.htm&h=206&w=321&sz=11&hl=en&start=30&tbnid=35_T2RG_HEkCsM:&tbnh=76&tbnw=118&prev=/images%3Fq%3Dgrasslands%2Bafrica%26start%3D20%26ndsp%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN • http://www.managingwholes.com/animal-impact.htm • http://www.eco-pros.com/grasslands.htm