Grassland Biomes

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Grassland Biomes

• Chapter 8

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8.1 Grasslands

• Objectives
• Describe the characteristics of grasslands
• Identify where grasslands are located
• A grassland is an ecosystem where there is too
  much water to form a desert, but not enough water
  to support a forest.
• The land between the desert and the forest.

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Grassland Climate

• A little wetter than the climate of a desert
• The desert-grassland boundary is the area between
  deserts and grasslands where increased rainfall
  enable some grasses to grow.
• This boundary shifts with long-term changes in
  climate patterns
• Rainfall is the most significant limiting factor
  in grasslands

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Grassland Video
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Grassland Organisms

• Grass is the most common
• Most of the mass of grass is below ground
• Grasses not as limited by factors such as rain
  and fires

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Grass and Fires

• Natural grass fires play an important role
• Fires help prevent forests from overgrowing
  grasslands
• Fires help by burning away dead grass allowing
  more water and air to reach soil
• Fires help release valuable nutrients
• Germination of seeds is aided by fire

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Animals Help Grasses

• Grazing animals help keep other vegetation from
  growing without harming grass
• Burrowing animals help to aerate the soil and by
  helping nutrients and water to reach the roots

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Rainfall and Grasslands

• Types of grasses vary based on the amount of
  rainfall
• Irrigation important to cultivated grass crops
• When it rains is also important
• Some grasslands have rainy and drought seasons
• Some plants have become drought-resistant

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Types of Grasslands

• Steppe (Chaparral)
• Prairie
• Savanna

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8.2 Steppes and Prairies

• Objectives
• Compare and contrast a steppe and a prairie
• Describe the importance of steppes and prairies
  in agriculture
• Steppes are grasslands that get less than 50 cm
  of rain a year
• Prairies are grasslands characterized by rolling
  hills, plains, and sod-forming grasses.

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Steppes and Prairies continued

• Steppes have very low rainfall and sparse plant
  life almost a desert
• U.S. prairies are
• Called the Great Plains
• Large fertile areas where most food is grown
• Grains breads and cereal
• Breadbasket

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Steppe and Prairie Climates

• Steppe
• 25cm to 50 cm rainfall per year
• Rain evaporates quickly only reaching top 25 cm
  of soil
• Temperature range from 5 oC to 30 oC
• Prairie
• 50 cm to 75 cm of rain per year
• Sometimes much more rain and floods
• Rain usually as thunderstorms

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Steppe and Prairie Organisms

• Prairie
• soil holds water well
• roots of grass (sod-forming grasses) form a mat
  called sod
• Humus is a layer of organic matter
• Holds water and provides nutrients and food

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Steppe and Prairie Organisms

• Steppes
• Short grass prairies
• Mostly bunchgrasses fine bladed grasses that
  grow in clumps
• Clumping helps save water by holding water in a
  small root area, under the shade of the grass.

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Steppe and Prairie Organisms

• Animal adaptations
• Migration
• Hibernation
• Burrowing
• Plant adaptations
• Seeds and pollen carried by wind
• Spreads over a wide area

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Buffalo
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Steppe and Prairie Organisms

• Migrating grazers do little damage
• But poor farming and ranching practices cause
  extensive damage
• Overgrazing, poor farming practices combined with
  droughts caused the Dust Bowl n the 30s.
• Today new techniques help reduce the impact

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8.3 Savannas

• Objectives
• Define savannas, and state where they are
  located.
• Explain how savannas can support a wide range of
  organisms.
• Savannas are tropical grasslands ranging from dry
  scrubland to wet open woodland.

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Savanna Video
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Savanna Climate

• Rainy seasons and long periods of drought
• As much as 150 cm rainfall per year
• Most falls heavily during thunderstorms
• Rest of year can be very dry
• Extreme climate demands a wide range of
  adaptations of organisms.

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Savanna Plants

• Grasses, shrubs and trees must be resistant to
  drought, fires and grazing animals
• Many grow runners
• long horizontal stems above or below ground
• Grasses grow in tufts
• large clumps of tall, coarse grasses
• Thorns or sharp leaves
• Protects from grazing animals
• They grow rapidly to recover quickly

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Savanna Animals

• Reproduce during rainy season when food is
  abundant
• Migrate to follow the rain
• Vertical feeding pattern
• Animals eat vegetation at different heights
• Can feed in the same area without competing
• Allows more animals to live on limited resources

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The End
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Quick Quiz 8QQ
1. Grasslands 2. Prairie 3. Steppe 4. Savanna

• Rhino
• Vertical feeding pattern
• Fire is important to health of the ecosystem
• Large areas with deep, fertile soils
• Mostly clumps of grasses with bare soil between
• Bison
• 50 cm to 75 cm of rain per year
• Climate wetter than a desert, but not as wet as a
  forest
• No real winter, but long dry season followed by
  intense wet season
• Grazing and burrowing animals help

1. 4
2. 4
3. 1
4. 2
5. 3
6. 2
7. 2
8. 1
9. 4
10. 1

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