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Tropical Rainy:
Tropical Wet & Dry:
Savannas
Tropical Savannas
Tropical Savannas or Grasslands are associated with the
tropical wet and dry climate type, but are not generally
considered to be a climax community. Instead, savannas
develop in regions where the climax community should be
some form of seasonal forest or woodland, but continuous
disturbances, such as drought or flooding, prevent the
establishment of those species of trees.
Photo credit: Dwigt Sieggreen
Drought
A long period of dry weather that can cause
crop failure.
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Heavy Rains & Floods
When it rains too much at one time, rivers can flood
their banks and cause soil erosion and other
damage.
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Climate
A tropical wet and dry climate
predominates in areas covered by
savanna growth. Mean monthly
temperatures are at or above 64° F and
annual precipitation averages between
30 and 50 inches. For at least five
months of the year, during the dry
season, less than 4 inches a month are
received. The dry season is associated
with the low sun period.
At times, parts of the savannas have
temperature increases and precipitation
decreases causing drought, where as,
other times there is the opposite and
flooding occurs.
Why is it important to learn about
climate change in East Africa?
• Climate change affects all parts of the globe.
• Our actions in the US affect other countries.
– How?
• Climate change in other parts of the world affects
the US.
– Why?
• What we learn about climate change in East
Africa can help us understand climate change
elsewhere.
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Vegetation
Savannas are characterized by a continuous cover of
perennial grasses, often 3 to 6 feet tall at maturity. They
may or may not also have an open canopy of droughtresistant, fire-resistant, trees, or an open shrub layer.
Climate Change affects
Savanna Vegetation
• Different plants grow
together
• Food for livestock
Farming options
• Growing season: length
and timing
• Type of crops grown
• Productivity of crops
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Grazing
Large mammals such as the elephant
open woodlands by debarking the trees
and by knocking them over. This opens
the woodland to grass invasion and
attracts a variety of grazing animals,
including zebras, wildebeest, and the
diverse antelopes of the Ethiopian
province. Grazers will both eat and
trample tree seedlings, inhibiting the
regrowth of the woodland. Only wellarmed species of shrubs and trees can
establish themselves in the clearings.
Overgrazing: if a grass savanna is
overgrazed, patches of bare ground will
be created. The bare ground will suffer
from increased evaporation and only
drought-resistant species can become
established.
Livelihood Systems
People who live in the
savannas have
different roles in their
community, most
effected by the
characteristics of their
geographic location.
• Raise Livestock
• Farming
• Non-farm income
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Farming
Photo Credit: Jennifer M. Olson
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Farm in Forest
Photo Credit: Jennifer M. Olson
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Climate can have and effect on Crops
Grown
•The growing season will shorten
•Corn will not grow in drier climates
•How much food the crops will yield
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Raise Livestock
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Non-Farm Income
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Land Management
Decisions about how to
manage the land are
made at different
levels:
• Household
• Community
• Regional
Land in the savanna
can be used for:
• Grazing livestock
• Farming
• Wildlife
• Firewood and other
uses
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Farm in Savanna
Farming
Photo Credit: Jennifer M. Olson
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Farms Expanding into Savanna
Photo Credit: Jennifer M. Olson
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Wildlife
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