Download Ecology Chapter 8 Voc. List: Grassland, Desert

Ecology Chapter 8
Voc. List: Grassland, Desert-grassland boundary, Roots, ground layer, herbaceous layer, Steppe, Sodformer grasses, Bunchgrasses, Humus, Prairie, Savanna, runners, tufts, and vertical feeding patterns
Grassland Ecosystem
Key terms:
1. Grassland-an ecosystem with enough water to support grass, shrubs, and trees.
2. Desert-grassland boundary-The area between deserts and grasslands where increase rainfall
supports some grasses to grow.
Characteristics of grasslands:
 Rainfall is usually 25-75 cm/year
 High evaporation rate
 Usually cultivated or used for grazing
 Usually native species have been replaced by invasive non-native species.
 Not forested-due to moisture &/or fires
o Fires are common due to lightning
o Fires are important in the development of grasslands because it keeps the
number of trees and shrubs low
 This allows grasses to grow and spread because most of the grass plant’s
mass is underground
 Ex.: One rye plant may grow only 2 mm but have up to 600 km of
roots beneath the soil. Therefore when a fire strikes the grasses
are relatively unharmed.
 Also, fires are a benefit because it burns a layer of dead grass
away converting it to valuable nutrients-act like a fertilizer.
 Animals graze or burrow
o All grasslands have large grazing animals such as antelope and bison
o Grasshoppers and other insects feed on the seeds and leaves of grasses, as do
small herbivores like mice, gophers, and prairie dogs that burrow in the ground
o In the North American prairies, the top consumers are coyotes, foxes, snakes,
and birds of prey
 Grasses are either sod-formers or bunch grasses
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
Seasonal Categories:
o Cool season-growth in Spring
 Ex. Bluegrass
o Warm season-growth in Summer
 Ex. Switch grass
Two types of Grasslands
1. Successional grasslands
 Often have native grasses and introduced species and assortments of herbs
2. Climax grasslands
 On the prairie legumes and asters are important
Three types of vegetation layers
1. Roots: 0.5 inches or more underground plant biomass
 Roots are deep enough that they absorb very little moisture from surface soil
2. Ground Layer: Dominated by mosses and plants with a rosette-type growth form, like
dandelions.
3. Herbaceous layer: Herbs
Grasslands can be divided up into three different biomes: Steppe, prairie, and savanna
1. Steppes –are grasslands of short bunchgrasses that get less than 50 cm of rain a year.
a. Found in Russia
b. Bunchgrasses are short, fine bladed grasses that form in clumps
c. Some animals hibernate in the colder areas to save energy
2. Prairie-are grasslands characterized by rolling hills, plains, and sod-former grasses.
a. Found in the United States-Great Plains (Breadbasket of the world), parts of South
America such as Argentina where they are known as pampas
b. Soil in prairies can hold water very well because soil organisms create air spaces that
hold the water.
c. Most of the grasses have roots that form a mat in the soil-Sod-former grasses
d. Humus helps hold moisture too-layer of organic material formed as plants and animals
decompose.
3. Savannas-are tropical or subtropical grasslands ranging from dry scrubland to wet, open
woodland
a. Found in parts of Asia, Africa, and South America
b. Vegetation contains lots of grass with some shrubs or trees, often widely spread.
c. Have rainy seasons and long periods of drought
i. Can have up to 150 cm of rain per year but mostly during the short rainy season
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d. Grasses, shrubs, and trees must be resistant to drought, fires, and grazing animals to
survive.
e. Runners are long horizontal stems above the ground. Runners are used by some plants
to reproduce quickly
f. Grasses grow in tufts-large clumps of tall, coarse grasses.
g. Animals have vertical feeding patterns-animals eat vegetation at different heights
allowing for different eating habits.
h. The trees and shrubs have thorns or sharp leaves that keep them from being eaten by
grazing animals, such as gazelles. They also grow and recover quickly when damaged.
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