Environmental Science Chapter 8 Sections 1, 2, & 3

 A GRASSLAND is an ecosystem in which there is more water than a desert but not enough for a forest  GRASSLANDS begin at the edges of desert and stretch to the edges of forests  Grasslands exist in Africa, Central Asia, North America, South America, and Australia  In the U.S., grasslands stretch from the Rocky Mountains to forests of the east and from Canada to Mexico GRASSLANDS

Grasslands of the US

 DESERT GRASSLAND BOUNDARY, is the area between deserts and grasslands where increased rainfall allows grasses to grow  If rainfall goes up the desert can become a grassland  If rainfall goes down a grassland will become a desert  Have hot and dry summers  Have cold winters GRASSLAND CLIMATES

 Grasslands are the most common and different in different parts of the world  How do natural fires help grasslands?  Keep the number of trees and shrubs low  Burn away dead grasses to make nutrients  Animals of North American Grasslands:  Bison, Prairie dogs, Coyotes, Foxes, Snakes, birds of prey. GRASSLAND ORGANISMS

 Can have heavy rain followed by drought  Plants have become drought-resistant by storing and retaining water  Three main types: PRAIRIE, STEPPE, and SAVANNA GRASSLANDS

 STEPPES are grasslands of short bunchgrasses that get less than 50cm of rain/yr.  Considered to be semiarid deserts  Some in SW U.S. STEPPES AND PRAIRIES

 PRAIRIES are grasslands characterized by rolling hills, plains, and sod-forming grasses  In the U.S., prairies are called the Great Plains  In Russian, Prairies are called Steppes  Veldt in South America  Pampas in Argentina  Known as the “Breadbaskets” STEPPES AND PRAIRIES

 Steppes – Receive 25cm to 50cm of rain/yr  Steppes – Temperatures -5ºC to 30ºC/yr  Prairies – Receive 50cm to 75cm rain/yr STEPPES AND PRAIRIES

 PRAIRIES have sod-forming grasses because the amount of rain that falls  An example is a Lawns  When roots of the grass die, they form a rich organic material called HUMUS  STEPPES have bunchgrasses, which are short, fine bladed grasses that grow in a clump STEPPES AND PRAIRIES

 Animals adapt by migrating, hibernating, or burrowing underground  Plants use the wind to disperse seeds  Over grazing helps create Dust Bowl STEPPES AND PRAIRIES

 

 SAVANNAS are tropical or subtropical grasslands ranging from dry scrubland to wet, open woodland.  Savannas occur in Africa, from India to SE Asia, and in Africa from the Sahara to Kalahari deserts to the Southern tip SAVANNAS

 Rainfall can be as much as 150cm/yr, but usually falls in short raining season  Usually hot and dry  Plants grow runners, long horizontal stems above or below ground.  Grasses grow in tufts, which are large clumps of tall, coarse grass. SAVANNAS

 Animals eat food by the Vertical Feeding Pattern – eating vegetation at different heights  Fig 8.10  Animals include gazelle, giraffe, rhinoceroses, elephants, and zebra SAVANNAS

