6.2.7. Tropical and subtropical grasslands, savannas, and shrublands

ACACIABaobab_tree_-near_Sand_River_Selous,_Selous_Game_Reserve,_Tanzania-8Tropical and subtropical grasslands, savannas, and shrublands are a grassland terrestrial biome located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes. Grasslands are dominated by grass and other herbaceous plants. Savannas are grasslands with scattered trees. Shrublands are dominated by woody or herbaceous shrubs.

Rainfall in tropical and subtropical grasslands, savannas, and shrublands is between 500 and 1300 millimeters (20 to 50 inches) a year, and can be highly seasonal, with the entire year’s rainfall sometimes occurring within a couple of weeks.

Tropical and subtropical grasslands, savannas, and shrublands occur on all continents but Antarctica. They are widespread in Africa, and are also found all throughout South Asia, the northern parts of South America and Australia, and the southern United States.

African Savannas occur between forest or woodland regions and grassland regions. The climate varies, with an average temperature of 27 °C with peaks of 30 °C in April and October, and between 300 and 1500 millimetres of rain per year. Flora includes:

  • Acacia (Tree)
    • Loses leaves in dry season to conserve moisture
    • Leafy canopy in rainy season (flattened by winds)
  • Baobab (Tree)
    • Stores water in trunk
    • Thick bark to protect it from fires in dry season
    • Long tap roots to reach underground moisture
    • Few leaves to reduce water loss through transpiration
  • Grass
    • Grow quickly to 3 or 4 meters in clumps
    • Shoots die in dry season leaving only roots
  • Low shrubs
    • Drought resistant
    • Small
    • Thorns not leaves

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