Transcript Slide 1

Changing Vegetation in the
Savanna:
Supplementary Material to Lesson 4 of the
“East Africa Climate Change Curriculum Unit”
Available at http://www.eaclipse.msu.edu/teaching_materials.html
Lesson 4 by Dwight Sieggreen & Barbara Naess.
PowerPoint based on presentation by Jennifer M. Olson,
2008.
The Eaclipse Project is supported by
National Science Foundation Award No. BCS/CNH 0709671.
http://eaclipse.msu.edu
© 2010 Michigan State University Board of Trustees
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Lesson 4: Changing Vegetation in the Savanna
Supplementary Material
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Rising Temperatures in East Africa
Inland
Coast
Arusha 1961-2005 (+1.1°C)
Zanzibar 1961-2005 (+1.9°C)
Zanzibar annual mean temperature time series (1961 - 2005)
Arusha mean annual temperature time series (1961 -2005)
y = 0.0423x - 57.902
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R = 0.5755
28.0
21.5
y = 0.0248x - 29.127
2
R = 0.5132
27.5
21.0
27.0
26.5
Temperature (C)
Temperature (C)
20.5
20.0
26.0
25.5
25.0
19.5
24.5
24.0
19.0
23.5
18.5
1961
1965
1969
1973
1977
1981
1985
1989
Years
Annual
Linear Trend
Source: Tanzania Meteorological Agency
1993
1997
2001
2005
2009
23.0
1961
1965
1969
1973
1977
1981
1985
1989
1993
1997
2001
2005
2009
Years
Annual mean
Linear Trend
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Variable Rainfall in East Africa
Inland
Coast
Zanzibar 1961-2005
Arusha 1961-2005
Zanzibar annual rainfall time series (1961 -2005)
Arusha annual rainfall time series (1961 -2005)
y = -6.2175x + 13146
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R = 0.0799
y = -0.792x + 3251.6
2
R = 0.0007
3000
1800
1600
2500
1400
2000
Rainfall (mm)
Rainfall (mm)
1200
1000
800
1500
1000
600
400
500
200
0
1961
0
1961
1965
1969
1973
1977
1981
1985
1989
1993
1997
2001
2005
2009
1965
1969
1973
1977
1981
1985
1989
1993
1997
2001
2005
2009
Years
Years
Annual rainfall
Annual rainfall
Source: Tanzania Meteorological Agency
Linear Trend
Linear Trend
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While climate change is affecting all of East Africa,
the savanna is the most vulnerable ecosystem in
East Africa
Savanna vegetation is highly vulnerable to
changes in temperature and moisture availability
These changes affect people’s ability to grow
crops and keep livestock in the savanna
(livelihood)
The EACLIPSE Project focuses on the savanna in
order to have the greatest possible impact
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Changing Vegetation
In this lesson, you will
• look at how changes in temperature
and water availability affect savanna
vegetation and
• make predictions as to how these
changes might affect people’s choices
of livelihoods and land use
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The savanna is a biome defined as a tropical
grassland with scattered shrubs and trees.
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Source: The Wild Classroom. http://www.thewildclassroom.com/biomes/precipitationgraph.html
Temperature vs. Precipitation Biome Graph
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Source: Kenya Ministry of Agriculture 1980: Agro-climatic zone map of Kenya 1980
Ecological Zones in East Africa
• Rainfall and evaporation determine moisture availability
• High temperatures speed up evaporation and evapotranspiration, decreasing
moisture availability
• In East Africa, seven ecological zones have been described based on
moisture availability and temperatures.
• Three of these zones (IV, V, and VI) include the savanna
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Table based on: Kenya Ministry of Agriculture 1980: Agro-climatic zone map of Kenya 1980
Source: Pratt, Greenway and Gwynne, 1966. A Classification of East African Rangeland. Journal of Applied Ecology, 3, 2: 369-382.
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Zone IV:
Dry Woodland
and Bushland
Higher moisture availability
Taller trees
More ground cover
Better growing conditions
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Zone V:
Bushland
Lower moisture availability
Scattered shrubs
Medium ground cover
Poor growing conditions
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Zone VI:
Bushland
and
Scrubland
Low moisture availability
Infrequent shrubs or scrub
Less ground cover
Very poor growing conditions
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Changes in Savanna Vegetation
Moisture availability will impact:
• crops
• livestock
• wildlife habitats
…affecting people’s livelihood options and land
use
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Impact on Crops
•
•
•
•
Timing of planting and harvest
Length of growing season
What crops can be planted, where
Whether some areas will be suitable for
farming
• Lower crop yields (productivity)
• Greater risk of crop failure
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Impact on Livestock
When there are higher temperatures and less moisture
availability:
• vegetation dries out faster
• water becomes scarce
• ground cover decreases (less forage for livestock)
• forage grows less quickly (lower productivity)
• forage species are of lower quality (palatability)
• droughts are more often
and more severe
• livestock diseases
are more frequent
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Impact on Wildlife Habitats
• Many wildlife are sensitive to changes in temperature
and to water availability
• Plants needed by some species may not grow
• Wildlife migration patterns may change
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The EACLIPSE project is collecting data on changes in
climate and ecosystems in East Africa.
The data collected include:
• temperature and rainfall
• plant species, and
• plant density (ground cover)
This information will help researchers predict the effects of
climate change and anticipate what kinds of livelihoods and
land use might be viable under different conditions.
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Discussion Questions
1. How does climate change affect vegetation in the
savanna?
2. What factors affect moisture availability?
3. What happens to savanna vegetation as moisture
availability decreases?
4. What would happen if there were not enough
moisture available for bushland and scrubland
vegetation?
5. How does the changing vegetation affect people’s
livelihood/land use options?
6. How does changing vegetation fit into the humanland-climate system loop?
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