Environmental ScienceChapter 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

https://www.youtube.com/watch?v=guTek7ipD4U

https://www.youtube.com/watch?v=o7Uwg8BT6qQ

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

https://www.youtube.com/watch?v=bW7PlTaawfQ