1. Grassland Biomes
Chapter 8

2. The land between the desert and the forest.
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.

4. 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

6. Grassland Video

7. 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

8. 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

9. 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

11. 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

12. Types of Grasslands
Steppe (Chaparral)
Prairie
Savanna

13. 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.

17. 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

18. Steppe and Prairie Climates
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

20. Steppe and Prairie Organisms
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

21. 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.

23. Steppe and Prairie Organisms
Animal adaptations
Migration
Hibernation
Burrowing
Plant adaptations
Seeds and pollen carried by wind
Spreads over a wide area

25. Buffalo

27. 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 30’s.
Today new techniques help reduce the impact

28. 8.3 Savannas Define savannas, and state where they are located.
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.

29. Savanna Video

30. 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.

31. 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

33. 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

38. The
End

39. 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 4 1 2 3
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