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Temperate Grasslands

Craig Christensen March 5, 2009 Development Studies. Temperate Grasslands. An ecotone A transitional zone between two different ecosystems Areas where precipitation is high enough to sustain grass, but (sometimes) only a few trees. Occur between forested and desert areas.

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Temperate Grasslands

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  1. Craig Christensen March 5, 2009 Development Studies Temperate Grasslands

  2. An ecotone • A transitional zone between two different ecosystems • Areas where precipitation is high enough to sustain grass, but (sometimes) only a few trees. • Occur between forested and desert areas. What are they?

  3. Where? * All occur in temperate regions (beyond 23.5 degrees North or South of the Equator.)

  4. 1.-Central/North America - Plains and Prairies • 2.- Argentina - Pampas • 3.- Hungary - Puszta • 4.- Russia - Steppes • 5.- Australia - Downs • 6.- New Zealand - Downs • 7.- South Africa - Veldts What are theycalled?

  5. Continental climate due to location • Hot summers, up to 30°C, below freezing for up to six months continuous. • Low ppt. (250-750mm annual) convectional rain in summer, snow in winter • High evaporation rates in summer • Periods of drought, and torrential rain can occur Climate

  6. Chernozem soils • Thick humus layer • Calcium carbonate deposits • Leaching during spring (snowmelt), and capillary rise in summer • Deeps roots and flat relief minimize erosion Soil

  7. Mainly grasses, with sparse bushes and trees • Height of grass relates to amount of precipitation • Vegetation is xerophytic and pyrophytic • NPP = 600g/m2/yr • Biomass = 1.6kg/m (low due to lack of trees) Vegetation

  8. Considering harsher climate, and lower availability of energy from primary producers, zoo-diversity quite low. • Species include: • Hoofed mammals (pronghorn, bison) • Ground rodents (prairie dogs) • Small carnivores (coyote, badgers, weasels) • Decomposers crucial in mixing soil. Fauna

  9. Largest reserve of nutrients is in Soil Very little lost to run-off and leaching Fire is important in returning nutrients to the soil. NutrientMovements

  10. Case Study:Canadian Prairies

  11. Grass species include: • Spear grass, wheat, barley, thread grass • Many small bushes: • Saskatoon, choke cherry, aster • Being on the edge of the ecotone, isolated forest communities exist, especially in Northern and Eastern limits. • Dedicious species : birch, willow, elder, aspen, poplar • Coniferous species : Spruce Flora and fauna

  12. Local topography can affect ecosystem • River valleys often have forest • Occasional deserts in valleys (Badlands) SpecialCharacteristics

  13. Climactic Hazards • Convectional summer rainfall can cause damaging hail and occasional tornadoes • Ex. Black Friday, summer ‘04 in Edmonton • Extreme winter cold (down to -40°C) troublesome for keeping livestock SpecialCharacteristics

  14. 95% of original, natural prairie has been converted to agricultural land. Little natural prairie remains. • Hunting of bison left only 250 wood bison at the end of the 19th century • Extinction and extirpation of many native species. • Swift fox • Introduction of pests • Dandelion • Colony Collapse disorder and bees • 30-70% losses reported in Winter ’06-’07 • Bees add $15 billion to US economy; similar impact could be felt Humanimpact

  15. http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/tempgrass/tempgras.htmlhttp://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/tempgrass/tempgras.html http://www.eldoradocountyweather.com/canada/climate/medicinehatclimate.html http://canadianbiodiversity.mcgill.ca/english/ecozones/prairies/prairies.htm# http://www.srd.gov.ab.ca/fishwildlife/status/bison/index.html http://www2.canada.com/edmonton/edmontonjournal/news/story.html?id=b9fa4403-a7f9-40b8-bcb9-f8a8f6966968 http://www.ars.usda.gov/News/docs.htm?docid=15572 Sources

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