Visualizing Environmental Science

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Rangelands

LEARNING OBJECTIVES

Rangeland Degradation

and Desertification

Grasses, the predominant vegetation of rangelands,

have fibrous root systems, in which many roots form diffuse

networks in the soil to anchor the plants. Plants with fibrous

roots hold the soil in place quite well, thereby reducing

soil erosion. Grazing animals eat the leafy shoots of the

grass, and the fibrous roots continue to develop, allowing

the plants to recover and regrow to their original size.

Carefully managed grazing is beneficial for grasslands.

Because rangeland vegetation is naturally adapted to graz-

ing, when grazing animals remove mature vegetation, the

activity stimulates rapid regrowth. At the same time, the

hooves of grazing animals disturb the soil surface enough

to allow rainfall to more effectively reach the root systems

of grazing plants. Several studies have reported that mod-

erate levels of grazing encourage greater plant diversity.

The carrying capacity of a rangeland is the maximum

number of animals the natural vegetation can sustain

over an indefinite period without deterioration of the

ecosystem. When the carrying capacity of a rangeland

1. Describe rangelands and their general uses.


2. Define desertification and explain its
   relationship to overgrazing.


3. Describe how conservation easements
   help protect privately owned rangelands.


4. Identify the government agencies
   that administer public rangelands and
   describe current issues of concern.

R

angelands are grasslands, in both temperate
and tropical climates, that serve as important
areas of food production for humans by pro-
viding fodder for livestock such as cattle,
sheep, and goats (Figure 13.8). Rangelands may be
mined for minerals and energy resources, used for recre-
ation, and preserved for biological habitat and for soil
and water resources. The predom-
inant vegetation of rangelands
includes grasses, forbs (small
plants other than grasses), and
shrubs.

rangeland

Grassland area that

is not intensively

managed and is used

for grazing livestock.

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Rangeland is considered a renewable resource when its
carrying capacity—the number of animals it can sustain
without suffering deterioration—is not exceeded.
Photographed along the Salmon River in Idaho.