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Tropical Grassland -Savanna-. Climate. Temperature 20 o -30 o 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 Sandy, dusty, high iron content (reddish color) Not very rich
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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 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 Soil Fertility
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
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
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- Diospyrosmespiliformis
Savanna has shrunk Some has been replanted by humans Introduction of exotic plants Changes in Last Century
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 Dry Season Wet Season Animal adaptations