Grassland Biomes
Chapter 8
8.1 Grasslands
Objectives
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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.
Grassland Climate
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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
Grassland Video
Grassland Organisms
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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
Grass and Fires
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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
Animals Help Grasses
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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
Rainfall and Grasslands
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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
Types of Grasslands
Steppe
(Chaparral)
Prairie
Savanna
8.2 Steppes and Prairies
Objectives
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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.
Steppes and Prairies
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continued
Steppes have very low rainfall and sparse
plant life – almost a desert
U.S. prairies are
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Called the Great Plains
Large fertile areas where most food is grown
Grains – breads and cereal
Breadbasket
Steppe and Prairie Climates
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Steppe
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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
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50 cm to 75 cm of rain per year
Sometimes much more rain and floods
Rain usually as thunderstorms
Steppe and Prairie Organisms
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Prairie
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soil holds water well
roots of grass (sod-forming grasses) form a
mat called sod
Humus is a layer of organic matter
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Holds water and provides nutrients and food
Steppe and Prairie Organisms
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Steppes
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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.
Steppe and Prairie Organisms
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Animal adaptations
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Migration
Hibernation
Burrowing
Plant adaptations
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Seeds and pollen carried by wind
Spreads over a wide area
Buffalo
Steppe and Prairie Organisms
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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
8.3 Savannas
Objectives
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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.
Savanna Video
Savanna Climate
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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.
Savanna Plants
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Grasses, shrubs and trees must be resistant to
drought, fires and grazing animals
Many grow runners
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Grasses grow in tufts
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large clumps of tall, coarse grasses
Thorns or sharp leaves
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long horizontal stems above or below ground
Protects from grazing animals
They grow rapidly to recover quickly
Savanna Animals
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Reproduce during rainy season when food
is abundant
Migrate to follow the rain
Vertical feeding pattern
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Animals eat vegetation at different heights
Can feed in the same area without competing
Allows more animals to live on limited
resources
The
End
Quick Quiz
1. Grasslands
2. Prairie
8QQ
3. Steppe
4. Savanna
1. 4
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Rhino
Vertical feeding pattern
Fire is important to health of the ecosystem
Large areas with deep,Click
fertileAgain
soils for Answers
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
2. 4
3. 1
4. 2
5. 3
6. 2
7. 2
8. 1
9. 4
10. 1