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Wildlife, Animals, and Plants
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Introductory
SPECIES: Bromus tectorum | Cheatgrass
ABBREVIATION :
BROTEC
SYNONYMS :
NO-ENTRY
SCS PLANT CODE :
NO-ENTRY
COMMON NAMES :
cheatgrass
downy chess
downy brome
broncograss
TAXONOMY :
The fully documented scientific name of cheatgrass is Bromus tectorum L.
LIFE FORM :
Graminoid
FEDERAL LEGAL STATUS :
NO-ENTRY
OTHER STATUS :
NO-ENTRY
COMPILED BY AND DATE :
Anne Bradley August 1986
LAST REVISED BY AND DATE :
NO-ENTRY
AUTHORSHIP AND CITATION :
Bradley, Anne F. 1986. Bromus tectorum. In: Remainder of Citation
DISTRIBUTION AND OCCURRENCE
SPECIES: Bromus tectorum | Cheatgrass
GENERAL DISTRIBUTION :
Cheatgrass is common in waste or disturbed areas in much of the western
United States. It is less prevalent west of the Cascades but more or
less ubiquitous to the east. It occurs from Alaska to Baja California,
east to Texas, South Carolina, and Maine. It is a native of southern
Europe and southwestern Asia and also may be found in north Africa [11].
ECOSYSTEMS :
FRES11 Spruce - fir
FRES17 Elm - ash - cottonwood
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES29 Sagebrush
FRES30 Desert shrub
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
FRES36 Mountain grasslands
FRES38 Plains grasslands
FRES39 Prairie
FRES40 Desert grasslands
STATES :
AL AK AZ AR CA CO CT DE GA HI
ID IL IN IA KS KY LA ME MD MA
MI MN MS MO MT NE NV NH NJ NM
NY NC ND OH OK OR PA RI SC SD
TN TX UT VT VA WA WV WI WY AB
BC MN NB NF NS ON PE PQ SK YT
ADMINISTRATIVE UNITS :
ACAD AGFO ARCH BADL BIHO BICA
BLCA BRCA BUFF CACH CANY CARE
CACA CEBR CHCU COLO COLM CODA
CRMO DEVA DEWA DETO DINO FIIS
FLFO FOBO FODO FOBU GATE GWCA
GLAC GLCA GRCA GRTE GRKO GRBA
GRSA GRSM GUMO INDU JODA LAME
LAVO LABE MEVE MOCA MORA NABR
NERI NOCA OBRI OLYM OZAR PEFO
PIPE PORE ROMO SAGU SAJH SAMO
SCBL SHEN SLBE SUCR THRO TICA
WACA WHIS WICA YELL ZION
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
3 Southern Pacific Border
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K011 Western ponderosa pine forest
K016 Eastern ponderosa pine forest
K017 Black Hills pine forest
K019 Arizona pine forest
K023 Juniper - pinyon woodland
K037 Mountain mahogany - oak scrub
K038 Great Basin sagebrush
K039 Blackbrush
K041 Creosotebush
K046 Desert
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K057 Galleta - three-awn shrubsteppe
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K067 Wheatgrass - bluestem - needlegrass
K070 Sandsage - bluestem prairie
K098 Northern floodplain forest
SAF COVER TYPES :
220 Rocky Mountain juniper
237 Interior ponderosa pine
238 Western juniper
239 Pinyon - juniper
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Cheatgrass is not a climax dominant or indicator species in any habitat
type classification because of its role as a seral invader after
disturbance. However, it can maintain its dominance for many years on
sites where the native vegetation has been eliminated or severely
reduced by overgrazing, cultivation, or frequent fire. In these
situations, cheatgrass remains the de facto climax dominant regardless
of the site potential.
VALUE AND USE
SPECIES: Bromus tectorum | Cheatgrass
WOOD PRODUCTS VALUE :
NO-ENTRY
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Cheatgrass provides valuable spring forage for all classes of livestock.
It is the major spring forage on lambing range in much of the
Intermountain West. Cheatgrass is an annual species and its production
varies greatly depending on moisture conditions. It can provide good
spring grazing, but its value during other seasons is limited when
compared with perennial species. It can be grazed all year, but the
proportion of nutrients to fiber is reduced when the herbage dries
[14,18]. The seed can provide food for upland game birds, such as the
chukar [26].
PALATABILITY :
The relish and degree of use shown by livestock and wildlife species for
cheatgrass in several western states is rated as follows [6].
CO MT ND UT WY
Cattle fair fair fair good fair
Sheep fair fair fair fair fair
Horses fair fair fair good fair
Pronghorn ---- good poor ---- ----
Elk fair poor ---- good ----
Mule deer poor poor poor good ----
Small mammals good poor ---- good ----
Small nongame birds ---- poor poor good ----
Upland game birds good poor poor good ----
Waterfowl ---- ---- ---- fair ----
NUTRITIONAL VALUE :
Cheatgrass can provide good nutrition for livestock in the spring, but
as it matures its nutritive value drops rapidly. The diet of cattle
grazing on cheatgrass range should be supplemented by a source of
energy, crude protein, and possibly some minerals (especially phosphorus
or zinc) from mid-June to mid-August or longer if animals are to continue
making good gains [18].
COVER VALUE :
Wildlife cover value in several western states is reported as follows
[6]:
UT CO MT
Elk poor ---- ----
Mule deer poor ---- ----
Pronghorn poor ---- ----
Upland game birds fair ---- poor
Waterfowl fair ---- good
Small nongame birds good ---- poor
Small mammals good good poor
VALUE FOR REHABILITATION OF DISTURBED SITES :
NO-ENTRY
OTHER USES AND VALUES :
Cheatgrass has been used with some success to eliminate more noxious
plants such as halogeton (Halogeton glomeratus). Halogeton begins its
lifecycle in the late spring when cheatgrass is drying. By this time,
most of the available soil moisture has been depleted by the maturing
cheatgrass. This reduction in moisture and the shade provided by a
dense stand of cheatgrass prevent halogeton from establishing [5].
Cheatgrass has fibrous roots and produces relatively large amounts of
litter. This makes a fairly efficient soil binder. If erosion is a
concern on grazing range, no more than 50 percent of the available
forage should be utilized [23].
MANAGEMENT CONSIDERATIONS :
Cheatgrass production is highly variable. Because of its year to year
fluctuations, recommending an optimal stocking rate is impractical. In
good years cheatgrass range can be utilized to reduce pressure on
perennial ranges. In poor production years, noncheatgrass range should
be made available for grazing [18].
In burned sagebrush communities, prompt rehabilitation before cheatgrass
can dominate is important. Along with grass seeding or other
improvement measures, livestock use must be closely controlled until
perennial plants are well established [27].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Bromus tectorum | Cheatgrass
GENERAL BOTANICAL CHARACTERISTICS :
Cheatgrass is an exotic, annual, or occasionally biennial grass
dominating millions of acres in the western United States. It is
particularly prevalent in the the palouse prairie and sagebrush
grassland of the Intermountain region and the Pacific Northwest. It is
an invasive species, favored by disturbances such as overgrazing,
cultivation, or frequent fire. Cheatgrass effectively outcompetes
native vegetation when cover of these species has been reduced. Its
rapid growth and its ability to utilize most of the available upper soil
moisture enables it to exclude seedlings of other species [10,24].
RAUNKIAER LIFE FORM :
Therophyte
REGENERATION PROCESSES :
Cheatgrass seed may germinate from fall through spring, depending on
moisture conditions. Seeds are inhibited by high light intensities and
high temperatures. This is particularly true for recently shed seed.
After 3 months of afterripening the impact of these factors lessens.
This inhibition prevents germination during the hot, dry summer months.
If the summer is unusually cool and wet, germination can take place.
Root elongation is rapid after germination and continues throughout the
winter in spite of low temperatures. By spring, roots are well
developed and and able to use available soil moisture more efficiently
than native species, which develop at a slower pace.
Stature and seed production is strongly influenced by site conditions.
On good sites without strong competition, robust plants with many
flowering culms develop. In unusually moist years (early summer rains),
a second seed crop may be produced [10].
Litter and rough microtopography aid the establishment of cheatgrass by
providing moderated temperatures and humidities for seeds [28]. Due to
germination, predation, and decomposition, fewer than 13 percent of seed
may survive until the following winter [17]. However, seeds stored
under dry conditions have germinated after more than 11 years [12].
SITE CHARACTERISTICS :
Cheatgrass is able to establish on a variety of soils and is
particularly favored by conditions of disturbance, such as those
produced by fire, overgrazing, or cultivation. It generally grows in
the 6 to 22 inch (15-56 cm) precipitation zone [13] but may also be
found in somewhat moister or drier conditions [12,14]. Although not
exacting in its requirements, cheatgrass appears to avoid areas of
extremely low precipitation or those with saline soils. It is a
shade-intolerant plant and obtains its best growth in foothill or
grassland conditions in the Intermountain region [14].
Elevational ranges for cheatgrass in several western states are as
follows [6]:
from 4,100 to 8,000 feet (1,250-2,450 m) in Utah
4,000 to 9,500 feet (1,220-2,900 m) in Colorado
3,700 to 8,500 feet (1,130-2,600 m) in Wyoming
3,200 to 6,300 feet ( 980-1,920 m) in Montan
SUCCESSIONAL STATUS :
Facultative Seral Species
Cheatgrass acts as both an early seral invader and a climax dominant on
many sites that historically supported a perennial grass and forb
understory. Cheatgrass invades sites soon after disturbance. It can
dominate by the 2nd year after fire and has been observed to retain its
position for at least 4 or 5 decades [3,4]. Site potential does not
seem to influence the success of cheatgrass. With an adequate seed
source it is able to overtake native vegetation throughout the range of
sagebrush communities. The overriding consideration in gauging its
potential success is the presence of rough microtopography and litter.
[25,28].
SEASONAL DEVELOPMENT :
Cheatgrass generally germinates in the fall and grows rapidly until cold
temperatures set in. When fall moisture is inadequate, it acts as a
spring annual. After germination in the fall, vegetative growth may be
as much as 2 to 4 inches (5-10 cm). For this degree of development, 2
inches (5 cm) or more of precipitation must accumulate. These
conditions occur about 1 in 5 years in southeastern Idaho and 1 in 8
years in southwestern Idaho.
Spring production may be substantial, but plants are generally dry by
early June. The stage of plant maturity is indicated by a change in
color. Plants change from green to purple to tan as they cure. The
purple stage may be induced by a sudden drop in temperature or droughty
conditions.
Seeds become viable while plants are still mostly green and before they
are disseminated. They ripen from late spring to early summer [10].
Cheatgrass phenology in Idaho has been documented as follows [14]:
Place Year Boot Full Anthesis Soft Purple Brown Ovary Seed
head dough dry falls
Lewiston 1950 ---- 3/6 5/6 5/27 6/3 6/10 6/10 ----
Boise 1957 4/23 4/29 5/6 ---- 5/6 6/14 ---- 6/14
Boise 1958 4/30 5/6 ---- 5/17 5/17 6/10 6/10 7/18
Boise 1960 4/21 5/6 5/13 5/20 5/20 ---- 5/26 6/2
FIRE ECOLOGY
SPECIES: Bromus tectorum | Cheatgrass
FIRE ECOLOGY OR ADAPTATIONS :
Cheatgrass is an annual grass and is able to complete its lifecycle in
the spring before the summer dry weather begins. Its complete drying
and fine structure make it extremely flammable. Frequent fires actually
favor cheatgrass by eliminating competing perennial vegetation. Its
seeds survive in the unburned organic material on a site. Rapid growth
and vigorous reproduction assure cheatgrass dominance in the postburn
stand.
POSTFIRE REGENERATION STRATEGY :
Initial-offsite colonizer (off-site, initial community)
FIRE EFFECTS
SPECIES: Bromus tectorum | Cheatgrass
IMMEDIATE FIRE EFFECT ON PLANT :
Cheatgrass is a highly flammable species due to its complete summer
drying, its fine structure, and its tendency to accumulate litter
[14,24]. Fire reduces cured plants to ash, but fire intensity may not
be great enough to consume the litter layer, even if associated shrubs
burn [28]. Seed on or in the mineral soil will probably survive even if
some of the litter is consumed.
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
Because of its flammability, cheatgrass greatly increases the fire
hazard on a site. The rate of spread, size, and frequency of fire all
increase. In Oregon, cheatgrass ranges were found to be 500 times more
likely to burn than noncheatgrass ranges. A forest stand with a
cheatgrass understory may suffer loss of regeneration because of
frequent burning. Cheatgrass fires spread very rapidly and may extend
into nearby stands of native vegetation and reduce the cover of valuable
perennial species.
Besides increasing fire frequency, the length of time cheatgrass remains
a hazard is longer than that for perennial grasses. Cheatgrass dries 4
to 6 weeks earlier than perennials and is susceptible to fire 1 to 2
months longer in the fall [23]. Several growth and habitat
characteristics of cheatgrass make it a fire hazard:
(1) it produces large quantities of seed that usually develop
into dense stands
(2) it can provide a continuous fuel between grassland and
forest stands
(3) it grows in the 6 to 22 inch precipitation zone, an area
with severe fire weather
(4) it cures early in the fire season
(5) its finely divided stems and flowering stem ignite readily
when dry
(6) it responds easily to any change in moisture conditions
because of its structure
There is a correlation between plant color and moisture status during
the curing process. Cheatgrass passes from green to a purple hue to a
straw color as it dries. The relationship is as follows:
Plant Color Moisture Content (%)
----------- --------------------
green > 100
purple 30-100
straw < 30
The onset of purple coloring should be taken as a warning that hazardous
fire conditions will develop within about 2 weeks. Observation of
coloration should be done close-up. A stand may appear to be purple
when most plant parts are still fairly green. In Montana, the average
time required to change from purple to straw color (100 to 30 percent
moisture) was 14 days [19].
PLANT RESPONSE TO FIRE :
Burning cheatgrass may reduce the next spring's production. On the
Snake River Plain near Dubois, Idaho fall-burned areas produced from 1/7
to 1/50 as much as unburned sites. The rate of spring growth was also
retarded. Early in the season, plants were half as large as those from
unburned areas. The difference became less evident as plants matured
[20].
Early summer fires produce similar results. Plant number may be
reduced, but those that do develop are often larger and produce great
quantities of seed. The earlier the fire, the greater the degree of
reduction [23]. Fires in pure cheatgrass stands tend to be less common
in the spring or early summer [24]. Fires generally occur in the summer
after seed is shed and is less vulnerable to burning. Reduction of
cheatgrass under these conditions is not great [24]. After a midsummer
fire in northern Nevada, cheatgrass density was reduced, but individual
plants were tremendously productive. Tiller and seed production both
were enhanced by burning. On an unburned control plot, the maximum
number of seeds on a plant was 250. On the burned plot, the minimum was
960 [27].
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
The amount of litter or ash left on a site is a good indicator of the
amount of cheatgrass seed still surviving. Seed is concentrated in the
litter, especially around shrubs. Since cheatgrass produces prolific
quantities of seed, even a large reduction in the seed pool will not
prevent it from regaining dominance on a site. In a northern Nevada
study, cheatgrass seed was reduced approximately 96 to 99 percent, from
5,000 to 8,000 seeds per square meter to 20 to 300 seeds per square
meter [28]. However, as few as 43 seeds per square meter are required
to reduce establishment of crested wheatgrass (Agropyron cristatum) and
633 seeds per square meter may prevent the establishment of perennials
[7].
FIRE MANAGEMENT CONSIDERATIONS :
NO-ENTRY
REFERENCES
SPECIES: Bromus tectorum | Cheatgrass
REFERENCES :
1. Bentley, J. R.; Fenner, R. L. 1958. Soil temperatures during burning
related to postfire seedbeds on woodland range. Journal of Forestry. 56:
737-740. [3285]
2. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals,
reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's
associations for the eleven western states. Tech. Note 301. Denver, CO:
U.S. Department of the Interior, Bureau of Land Management. 169 p.
[434]
3. Cline, J. F.; Uresk, D. W.; Rickard, W. H. 1977. Plants and soil of a
sagebrush community on the Hanford Reservation. Northwest Science.
51(1): 60-70. [653]
4. Daubenmire, Rexford F. 1975. Plant succession on abandoned fields, and
fire influences, in a steppe area in southeastern Washington. Northwest
Science. 49(1): 36-48. [745]
5. DeFlon, James G. 1986. The case for cheat grass. Rangelands. 8(1):
14-17. [775]
6. Dittberner, Phillip L.; Olson, Michael R. 1983. The plant information
network (PIN) data base: Colorado, Montana, North Dakota, Utah, and
Wyoming. FWS/OBS-83/86. Washington, DC: U.S. Department of the Interior,
Fish and Wildlife Service. 786 p. [806]
7. Evans, Raymond A. 1961. Eff. of diff. densities of downy brome (Bromus
tectorum) on grwth & surv. of crested wheatgrass (Agropryon desertorum)
in the greenhouse. Weeds. 9: 216-223. [875]
8. Evans, Raymond A.; Young, James A. 1978. Effectiveness of rehabilitation
practices following wildfire in a degraded big sagebrush-downy brome
community. Journal of Range Management. 31(3): 185-188. [880]
9. Eyre, F. H., ed. 1980. Forest cover types of the United States and
Canada. Washington, DC: Society of American Foresters. 148 p. [905]
10. Harris, Grant A. 1967. Some competitive relationships between Agropyron
spicatum and Bromus tectorum. Ecological Monographs. 37(2): 89-111.
[1093]
11. Hitchcock, C. Leo; Cronquist, Arthur; Ownbey, Marion. 1969. Vascular
plants of the Pacific Northwest. Part 1: Vascular cryptograms,
gymnosperms, and monocotyledons. Seattle, WA: University of Washington
Press. 914 p. [1169]
12. Hulbert, Lloyd C. 1955. Ecological studies of Bromus tectorum and other
annual bromegrasses. Ecological Monographs. 25(2): 181-213. [1205]
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range research. Journal of Forestry. 45(8): 555-564. [9930]
14. Klemmedson, James O.; Smith, Justin G. 1964. Cheatgrass (Bromus
tectorum). Botanical Review. 30: 226-262. [1353]
15. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation
of the conterminous United States. Special Publication No. 36. New York:
American Geographical Society. 77 p. [1384]
16. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession
following large northern Rocky Mountain wildfires. In: Proceedings, Tall
Timbers fire ecology conference and Intermountain Fire Research Council
fire and land management symposium; 1974 October 8-10; Missoula, MT. No.
14. Tallahassee, FL: Tall Timbers Research Station: 355-373. [1496]
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tectorum: variation in time and space. Journal of Ecology. 71: 69-93.
[1504]
18. Murray, R. B.; Mayland, H. F.; Van Soest, P. J. 1978. Growth and
nutritional value to cattle of grasses on cheatgrass range in southern
Idaho. Research Paper INT-199. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Forest and Range Experiment
Station. 57 p. [1723]
19. Mutch, Robert W. 1967. Cheatgrass coloration--a key to flammability?.
Journal of Range Management. 20(4): 259-260. [1725]
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cheatgrass fires. National Wool Grower. 35(4): 13. [1857]
21. Raunkiaer, C. 1934. The life forms of plants and statistical plant
geography. Oxford: Clarendon Press. 632 p. [2843]
22. Sampson, Arthur W. 1944. Plant succession on burned chaparral lands in
northern California. Bull. 65. Berkeley, CA: University of California,
College of Agriculture, Agricultural Experiment Station. 144 p. [2050]
23. Stewart, George; Hull, A.C. 1949. Cheatgrass (Bromus tectorum L.)--an
ecologic intruder in southern Idaho. Ecology. 30(1): 58-74. [2252]
24. Tisdale, E. W.; Hironaka, M. 1981. The sagebrush-grass region: a review
of the ecological literature. Bull. 33. Moscow, ID: University of Idaho,
Forest, Wildlife and Range Experiment Station. 31 p. [2344]
25. Young, James A.; Evans, Raymond A. 1973. Downy brome--intruder in the
plant succession of big sagebrush communities in the Great Basin.
Journal of Range Management. 26(6): 410-415. [2651]
26. Young, James A.; Evans, Raymond A. 1978. Germination requirements as
determinants of species composition of Artemisia rangeland communities.
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rangeland congress; 1978 August 14-18; Denver, CO. Denver, CO: Society
for Range Management: 366-369. [2656]
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wildfires in sagebrush grasslands. Journal of Range Management. 31(4):
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potential downy brome competition after wildfires. Journal of Range
Management. 29(4): 322-325. [2677]
29. Stickney, Peter F. 1989. Seral origin of species originating in northern
Rocky Mountain forests. Unpublished draft on file at: U.S. Department of
Agriculture, Forest Service, Intermountain Research Station, Fire
Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090]
30. U.S. Department of Agriculture, Soil Conservation Service. 1982.
National list of scientific plant names. Vol. 1. List of plant names.
SCS-TP-159. Washington, DC. 416 p. [11573]
Index
Related categories for Species: Bromus tectorum
| Cheatgrass
|
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