Tropical Grassland -Savanna-

Tropical Grassland-Savanna-

Climate Temperature

20o-30o Celsius

Average Rainfall 100-400 mm per year (80% in wet season)

Sunlight Lots of sun during dry season

Grasses are mostly C4

Soil Fertility

Soil Fertility Sandy, dusty, high iron

content (reddish color) Not very rich

Termites turn the soil to air it

Dead plant matter can’t decompose in dry season

Seasonal Changes Wet

4-5 months Equatorial low pressure belt Heavy convectional storms

80% total annual rainfall

Dry Strong, steady “trade winds”

Dry and warm as they blow towards equator

Characteristics Vegetation

100-200 mm rainfall-only grasses 300 mm rainfall-shrubs < 300 mm rainfall-solitary trees < 400 mm rainfall- trees, canopy, shade

Trees-deciduous-lose leaves in winter Shrubs/Grasses-C4

Geography Location

5o-15o north and south of equator Llanos (Venezuela), Campos (Brazil), Central

Africa, Australia, Mexico

Limiting Factors Rain Fire Soil Fertility

Animal Life and Adaptations Form herds and

colonies for protection Care for young Lookout for predators

Meekrat- Suricata suricatta siricata

Nigriceps Ant- Crematogaster nigriceps

Animal Life and Adaptations Grazing herbivores

adopt migratory lifestyles Long legs, wings

African Elephant- Loxodonta africana

Grant’s Zebra- Equusburchelli bohmi

Animal Life and Adaptations Animals give birth only

during rainy season Food is abundant More offspring than

predators

Dama Gazelle- Gazella dama

Animal Life and Adaptations

Herbivores reduce competition for food Feed at different heights

Giraffe- Giraffa camelopardalis

Darma dik-dik- Madoqua kirkii

Animal Life and Adaptations

Small animals burrow deep underground Water Dormant during dry

season

African Ground Squirrel- Xerus inauris

Plant Life and Adaptations Fire

Thick, fire resistant bark Buds in bark sprout after

fires Seeds that germinate

in ashes

Bottle trees- Adansonia digitata

Plant Life and Adaptations

Fire Lignotubers

Eucalyptus trees- Eucalyptus globulus

Plant Life and Adaptations

Water “drought deciduous”

River Bushwillow- Combretum erythrophyllum

Plant Life and Adaptations

Water Long roots extending far underground (Taproot

system) Corkscrew-shaped awns

Red Oat Grass- Themeda triandra

Plant Life and Adaptations

Defense Thorns and

leathery,sharp leaves for protection

Toxic chemicals

Elephant Grass- Pennistum

purpureum Whistling Thorn tree-

Acacia dreparalobium

Plant Life and Adaptations

Senegal Gum Acacia- Acacia senegal

Jackal Berry Tree- Diospyros mespiliformis

Changes in Last Century Savanna has shrunk

Some has been replanted by humans

Introduction of exotic plants

Human Activities Nomadic cattle grazing

Soil erosion by overgrazing

Man-made fire Used to control grasses and for hunting

Tree clearing Climate change Introduction of exotic plants

Conservation Replanting destroyed grasses Monitoring endangered plants and animals

Preserves and National Parks

The Circle of Life

Wet Season

Dry Season

Animal adaptations