Index of Species Information
SPECIES: Wyethia amplexicaulis
Introductory
SPECIES: Wyethia amplexicaulis
AUTHORSHIP AND CITATION :
Matthews, Robin F. 1993. Wyethia amplexicaulis. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: http://www.fs.fed.us/database/feis/ [].
ABBREVIATION :
WYEAMP
SYNONYMS :
NO-ENTRY
SCS PLANT CODE :
WYAM
COMMON NAMES :
mules-ears
mules ears
wyethia
mule ear dock
black sunflower
TAXONOMY :
The currently accepted scientific name of mules-ears is Wyethia
amplexicaulis (Nutt.) Nutt. It is in the family Asteraceae [12,32].
Mules-ears apparently hybridizes with W. arizonica Gray [12] and
with arrowleaf balsamroot (Balsamorhiza sagittata) [35].
LIFE FORM :
Forb
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
NO-ENTRY
DISTRIBUTION AND OCCURRENCE
SPECIES: Wyethia amplexicaulis
GENERAL DISTRIBUTION :
Mules-ears is distributed from Washington to Montana and south to
Colorado and Nevada [12,16,32].
ECOSYSTEMS :
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES28 Western hardwoods
FRES29 Sagebrush
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
FRES36 Mountain grasslands
FRES37 Mountain meadows
STATES :
CO ID MT NV OR UT WA WY
BLM PHYSIOGRAPHIC REGIONS :
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
KUCHLER PLANT ASSOCIATIONS :
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K015 Western spruce - fir forest
K018 Pine - Douglas-fir forest
K020 Spruce - fir - Douglas-fir forest
K021 Southwestern spruce - fir forest
K023 Juniper - pinyon woodland
K024 Juniper steppe woodland
K037 Mountain-mahogany - oak scrub
K038 Great Basin sagebrush
K050 Fescue - wheatgrass
K051 Wheatgrass - bluegrass
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K063 Foothills prairie
SAF COVER TYPES :
206 Engelmann spruce - subalpine fir
210 Interior Douglas-fir
217 Aspen
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 :
Mules-ears has a wide ecological amplitude, occurring in many plant
communities. It is most abundant in mesic sagebrush (Artemisia
spp.)-grassland habitats. It is also common in woodlands and seral
coniferous forests above the elevational limits of sagebrush [28,35].
Trembling aspen (Populus tremuloides)/mules-ears community types in the
Intermountain region are minor and mostly confined to the north [17].
In the Bridger-Teton, Caribou, and Targhee National Forests, these types
usually result from severe overgrazing. These communities generally
have an open canopy of trembling aspen with the herbaceous layer
completely dominated by mules-ears [18,37]. Other species sometimes
cooccurring include mountain snowberry (Symphoricarpos oreophilus),
Saskatoon serviceberry (Amelanchier alnifolia), western stickseed
(Hackelia floribunda), common dandelion (Taraxacum officinale), western
coneflower (Rudbeckia occidentalis), cinquefoil (Potentilla spp.),
lupine (Lupinus spp.), butterweed groundsel (Senecio serra), California
brome (Bromus carinatus), slender wheatgrass (Elymus trachycaulus), blue
wildrye (E. glaucus), and Kentucky bluegrass (Poa pratense) [17,18,37].
Trembling aspen/mules-ears community types in the Intermountain region
are fairly stable [17,18,36]. Mueggler and Campbell [18] suggested that
they should be recognized as distinct habitat types on the Caribou and
Targhee National Forests.
Other species commonly associated with mules-ears include ninebark
(Physocarpus malvaceus), Oregon-grape (Mahonia repens), Gambel oak
(Quercus gambelii), Wood's rose (Rosa woodsii), antelope bitterbrush
(Purshia tridentata), rubber rabbitbrush (Chrysothamnus nauseosus), low
rabbitbrush (C. viscidiflorus), curlleaf mountain-mahogany (Cercocarpus
ledifolius), Rocky Mountain maple (Acer glabrum), arrowleaf balsamroot,
western yarrow (Achillea millefolium), slenderleaf collomia (Collomia
linearis), duncecap larkspur (Delphinium occidentale), buckwheat
(Eriogonum spp.), sticky geranium (Geranium viscosissimum), bluebunch
wheatgrass (Pseudoroegneria spicata), Idaho fescue (Festuca idahoensis),
cheatgrass (Bromus tectorum), prairie junegrass (Koeleria cristata), and
bluegrass (Poa spp.) [2,3,11,14].
Publications listing mules-ears as a dominant herbaceous-layer species
are as follows:
Subalpine forb community types of the Bridger-Teton National Forest,
Wyoming [11]
Aspen community types on the Caribou and Targhee National Forests in
southeastern Idaho [18]
Aspen community types of the Intermountain Region [17]
The vegetation of the Wasatch Mountains, Utah and Idaho [22]
Aspen community type classifications in the Intermountain West [36]
Aspen community types on the Bridger-Teton National Forest in western
Wyoming [37].
MANAGEMENT CONSIDERATIONS
SPECIES: Wyethia amplexicaulis
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Mule deer prefer mules-ears early in the growing season [5,19,24].
Sheep forage new leaves in spring and early summer. Mature foliage is
coarse and harsh, and plants dry out by mid-summer, so it is little used
after early summer. Elk, deer, and all classes of livestock eat the
flower heads [26,28,35].
PALATABILITY :
Mules-ears is generally unpalatable [1,8,19,37]. However, the leaves
may be moderately palatable in the spring, and flower heads are relished
by livestock, deer, and elk [11,28].
NUTRITIONAL VALUE :
Mules-ears is generally poor in energy and protein value [8]. July
estimates for crude protein and in-vitro dry matter digestiblity for
mules-ears collected in a moist meadow were 11.1 percent and 75.7
percent, respectively [27].
COVER VALUE :
Mules-ears often forms dense stands [22,28,30,37] and may provide good
cover for birds and small mammals [8]. Blue grouse nests in Utah are
commonly located in sagebrush-mules-ears vegetation near trees or tall
shrubs [23].
VALUE FOR REHABILITATION OF DISTURBED SITES :
In the Wasatch Mountains of Utah and Idaho, mules-ears forms dense cover
and its well-developed root system aids in preventing erosion [22].
Mules-ears may be useful in revegetating mine spoils [35].
OTHER USES AND VALUES :
Native Americans fermented the roots of mules-ears for 2 days in a pit
heated with hot stones to make a sweet flavored food [26,28].
OTHER MANAGEMENT CONSIDERATIONS :
Mules-ears-dominated understory communities in the Intermountain region
have relatively high production levels, but the production is mainly
from unpalatable mules-ears [11,17]. These stands are poor livestock
range and poor wildlife habitat because of a lack of structural and
species diversity [17].
The understory of many trembling aspen/mules-ears stands has been
altered due to severe grazing pressure, as evidenced by the overwhelming
dominance of mules-ears in environments that could support palatable
grasses and forbs [17]. When grazing pressure is less intense and a
shrub layer is present, such as in trembling aspen/mountain
snowberry-mules-ears community types, ground-level shading may be too
intense to support a dominant cover of mules-ears [17].
Mules-ears dominates some mountain meadows in northeastern Oregon that
are in poor condition due to grazing. It is less abundant in meadows
that have been improved by seeding with desirable forage [27].
Mules-ears has a negative effect on available soil moisture because it
uses large amounts of moisture early in the season [19,37]. If grazing
was restricted, mules-ears would probably still dominate many sites to
the exclusion of other plants because of this factor [37].
Triclopyr or 2,4-D applied early in the blooming period effectively
controls mules-ears [20,30,33].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Wyethia amplexicaulis
GENERAL BOTANICAL CHARACTERISTICS :
Mules-ears is a native, perennial, cool-season forb with stems up to 32
inches (80 cm) tall. The leaves are alternate and are 8 to 16 inches
(20-40 cm) long and 2 to 6 inches (5-15 cm) wide. There are usually
several flower heads but flower heads may occasionally be solitary. The
fruits are achenes [12,16,32]. Mules-ears has a stout taproot up to 9
inches (22 cm) in circumference. The taproot may reach depths of over 6
feet (180 cm). Strong lateral roots run 3 to 4 feet (90-120 cm) from
the main root [31]. Mules-ears is strongly aromatic [1,19].
RAUNKIAER LIFE FORM :
Hemicryptophyte
Geophyte
REGENERATION PROCESSES :
Mules-ears reproduces by seed [19,26,30,35]. Seeds germinate without
stratification, but a cool-moist stratification greatly enhances
germination. Best germination occurs when seeds are stratified for 4
weeks at 35 to 41 degrees Fahrenheit (2-5 deg C) [35].
Mules-ears sprouts from underground rootstalks or from the root crown
following damage to aboveground portions of the plant [20,37].
SITE CHARACTERISTICS :
Mules-ears is found in moist draws, meadows, open woods, and open
grasslands [12,13,19,26]. Elevational limits of mules-ears are from
4,500 to 11,000 feet (1,360-3,300 m) [8]. Mules-ears requires 10 to 18
inches (25.4-45.7 cm) of annual precipitation [19]. It grows well on
sandy loam, loam, and clay-loam textured soils [8], but is apparently
most aggressive in heavy clay soils [11,18]. Mules-ears grows well on
gentle to moderately steep slopes [8].
The trembling aspen/mules-ears community types of the Bridger-Teton,
Caribou, and Targhee National Forests are usually found below 7,000 feet
(2,120 m). They most often occur in heavy clay soils with slopes seldom
exceeding 25 percent [17,18,37].
Mules-ears-dominated subalpine forb communities also occur in heavy clay
soils on the Bridger-Teton National Forest. The forb communities are
characterized by large stands of mules-ears surrounded by trembling
aspen or subalpine fir (Abies lasiocarpa). They are found at the lower
elevations of the subalpine zone (average elevation 7,296 feet [2,210
m]). Average soil pH of these stands is 6.4 [11].
SUCCESSIONAL STATUS :
Facultative Seral Species
Mules-ears is highly competitive and aggressive and often occurs in
large, dense, almost pure stands [26,28,30]. Its aggression on some
sites may be partly attributed to its ability to dominate heavy clay
soils [28] and its tendency to monopolize soil moisture [19,37]. It
excludes other species in some heavily grazed areas [11,17,35]. Even
when grazing pressure is eliminated, mules-ears persists for a long time
[22].
Mules-ears is common in seral coniferous forests within its range [35].
SEASONAL DEVELOPMENT :
Mules-ears begins growth in March or April and flowers from April until
June [26]. Annual growth usually dries up by July [31].
FIRE ECOLOGY
SPECIES: Wyethia amplexicaulis
FIRE ECOLOGY OR ADAPTATIONS :
Mules-ears probably sprouts after fire damage. Postfire sprouting has
not been documented, but sprouting was noted following top-kill by
disking on the Targhee National Forest. Mules-ears apparently sprouted
from damaged roots [37].
Mules-ears is covered with a varnish-like resin [16] that may make it fairly
flammable when cured.
POSTFIRE REGENERATION STRATEGY :
Geophyte, growing points deep in soil
FIRE EFFECTS
SPECIES: Wyethia amplexicaulis
IMMEDIATE FIRE EFFECT ON PLANT :
Information on the effect of fire on mules-ears is not available in the
literature. Moderately severe or severe fires probably at least
top-kill mules-ears.
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
NO-ENTRY
PLANT RESPONSE TO FIRE :
Young and Evans [34] reported that mules-ears density generally
increases after rangeland fires. Postfire frequencies (percent)
for mules-ears in seral big sagebrush (Artemisia tridentata)/Thurber
needlegrass (Stipa thurberiana) communities after three summer wildfires
in Nevada follow:
Postfire Year
Location 1 2 3 4
__________________________________________________________
Red Rock 3 2 2 4
Hallelujah Junction 2 1 T ---
Seven Lakes 2 2 --- ---
At the Red Rock site, mules-ears was present within 1 month following
the fire.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
NO-ENTRY
FIRE MANAGEMENT CONSIDERATIONS :
Predictions of fire behavior and suggested guidelines for management
with prescribed fire have been formulated for trembling aspen/mules-ears
community types in southeastern Idaho and western Wyoming. It has been
suggested that fires in these communities are likely to be of low
intensity and will usually spread slowly. Fuel loadings are marginal
for sustained spread. Fires may occasionally crown but prescribed fires
could be easily controlled in trembling aspen/mules-ears communities [7].
Brown [6] determined that the moisture content of mules-ears in
trembling aspen stands is approximately 300 percent when green, but may
be as low as 25 percent when cured.
REFERENCES
SPECIES: Wyethia amplexicaulis
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