Watershed 

Protection on Sagebrush Steppe: 

Characteristics and

Importance of Litter

Cover

By Bruce P. Van Haveren

Science and Research Advisor

BLM, National Science and 

Technology Center

Ground cover has typically

been defined as the area

of ground covered by vegetation and litter. Litter has been

defined by some authorities as

dead organic matter lying

on the mineral soil; others

have included standing dead

material and dead fallen

organic material. On the basis

of these definitions, litter in

sagebrush steppe ecosystems

includes fallen dead leaves,

stems, bark, flowers, and

seeds of shrubs, forbs, and

grasses; dead cushion plants

and moss; detached lichen;

animal feces and dead insects;

and unidentifiable amorphous

woody organic matter (humic

litter) lying on the mineral

soil surface.

Litter seems to be the most

prevalent ground cover component in sagebrush steppe

ecosystems. Researchers have

collected long-term data on

vegetation and ground cover

characteristics in high-elevation sagebrush steppe in

south-central Wyoming.

According to these data, litter

was consistently the largest

ground cover component,

averaging 46% over a 14-year

measurement period. Data

from sagebrush steppe plant

communities in North Park,

Colorado, also showed litter

to be the largest component

(>30% of ground cover).

Litter provides a source of

organic matter for incorporation into the underlying mineral soil, acts as a source of

carbon for organisms carrying

out decomposing functions,

and insulates the soil from

extreme air temperatures. Litter also plays a critical role in

watershed protection by promoting water infiltration and

protecting the soil from the

erosive energy of raindrops

and surface runoff. 

Although ground cover

requirements have been established for many rangeland

areas in the West, scientific

information about litter characteristics and the role of

litter in watershed protection is not readily available.

The hydrologic and geomorphic properties of litter

have received little attention. I could not find any

published information about

the disposition of litter in

burned, shrub–steppe plant

communities. Others have

concluded that we have no

clear concept of what constitutes aboveground litter in

arid and semiarid ecosystems. 

From the standpoint of

watershed protection, litter

is definitely good—the

more the better. But what

kinds of litter provide the

best watershed protection?

What types of litter occur in

sagebrush steppe? Observations from high-elevation

sagebrush steppe in southern

Wyoming suggest the following litter classification:

• Herbaceous (stems and

leaves of grasses and

sedges)

• Humic litter (amorphous,

small, partly decomposed

organic matter)

• Animal feces and dead

insects

• Woody parts of sagebrush

and other shrubs

• Shrub and forb leaves

• Seeds and flower parts

• Dead parts of cushion

plants (including mosses,

detached lichens, cryptogams)

The preceding classification

is a reflection of the parent

material, or source, of the

litter. Litter might also be

NO. 64 DATE 02/20/03

Range

Range

Resource Note 64

page 1
classified on the basis of age

and decay. One researcher

concluded that soil erosion

was greater on sites with

small, easily detached litter

than on sites having large,

firmly anchored litter. Some

researchers differentiated

between easily decomposed

labile litter, such as leaf and

flower parts, and highly

persistent litter with a high

lignin content, such as wood.

Persistent litter probably has

more watershed protection

value than the easily oxidized,

high-cellulose litter derived

from herbaceous vegetation.

The Table shows the percentage of occurrence and

watershed protection value

of various types of litter in

sagebrush steppe.

Contact

Bruce P. Van Haveren, Senior

Scientist

National Science and 

Technology Center

Denver Federal Center

Building 50

P.O. Box 25047

Denver, CO 80225-0047

Phone: 303-236-0161

Email: 

Bruce_VanHaveren@blm.gov

Range

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Resource Note 64

page 2

Table. Litter types, percentage of occurrence, and the watershed protection value for sagebrush steppe rangeland.

Occurrence Watershed protection

Litter type (%) value

Herbaceous 45 Moderate

Shrub and forb leaves 19 Moderate

Humic material 15 Low

Woody parts of shrubs 11 High

Dead cushion plants 6 High

Seeds and flowers 3 Low

Animal feces 1 Moderate