The Research Project Summary
Vegetation response to restoration treatments in ponderosa pine-Douglas-fir forests of western Montana
also
provides information on prescribed fire and postfire response of plant species, including
onespike oatgrass, that was not available when this species review was written.
The degree to which onespike oatgrass provides cover for wildlife species is
as follows [8]:
UT WY
Pronghorn Poor Poor
Elk Poor Poor
Mule deer Poor Poor
White-tailed deer ---- Poor
Small mammals Fair Fair
Small nongame birds Poor Fair
Upland game birds Poor Fair
Waterfowl Poor Poor
Onespike oatgrass is a native, densely tufted perennial bunchgrass [5,17,44]. The centers of the spreading tufts ultimately die out and old sheaths persist at the base of the plants [5]. Culms typically grow 4 to 12 inches (10-30 cm) in height [5,16,26,44]. The inflorescence is a panicle mostly reduced to a single spikelet, but 2 or 3 spikelets may occasionally be present [5,17,18,26]. The root system of onespike oatgrass is shallow and fibrous [20,31,33].
Onespike oatgrass occurs from British Columbia south to California and east to Alberta, Montana, Wyoming, South Dakota, Utah, and Colorado [5,9,17,44].
Little information is available in the literature that addresses onespike oatgrass adaptations to fire.
Historically, Sandberg bluegrass-onespike oatgrass plant associations in the Columbia River Basin had such low biomass that they typically did not carry fire, and have probably rarely burned [1].
Johnson and Simon [22] state that onespike oatgrass is 'probably' resistant to fire based on its high moisture content throughout summer, and may in fact respond favorably to burning. However, burning of frost-heaved onespike oatgrass may cause damage due to exposure of the root crown to heat.
They also state that fire does not spread well in Sandberg bluegrass-onespike oatgrass plant associations of the Wallowa-Whitman National Forest due to insufficient fuel availability and high rock cover.
In the Pacific Northwest, other oatgrass species have been described as moderately resistant to fire [41].
FIRE REGIMES:
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES". For further information regarding FIRE REGIMES and fire ecology of areas where onespike oatgrass is found, see the 'Fire Ecology and Adaptations' section of the FEIS Species Review for the dominant plant species listed below.
Onespike oatgrass occurs on dry to moist sites from prairies and foothills to open parks and ridges at higher elevations [5,16,18,26,44]. Sites are often rocky with shallow, poorly drained soils [7,14,16,26,33]. Stands of onespike oatgrass are limited to intermediate elevations in the Sierra Nevada and in northeastern California, where they occur in high desert or lava areas [31]. Onespike oatgrass grows at elevations of 2,970 to 10,560 feet (900-3200 m) in California [16], and 7,000 to 10,000 feet (2130-3050 m) in Utah [44].
Onespike oatgrass frequently codominates plant communities with Sandberg bluegrass on bluegrass scablands characterized by thin, rocky soils. These scablands are typically located on intermountain plateaus and ridges derived from Columbia River basaltic flows east of the Cascade Mountains and west of the Rocky Mountains in the Pacific Northwest [32]. Similar scablands are described on central Oregon pumice-derived substrates [32,40].
210 Interior Douglas-fir
217 Aspen
218 Lodgepole pine
219 Limber pine
220 Rocky Mountain juniper
237 Interior ponderosa pine
238 Western juniper
239 Pinyon-juniper
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir-spruce
FRES26 Lodgepole pine
FRES29 Sagebrush
FRES34 Chaparral-mountain shrub
FRES35 Pinyon-juniper
FRES36 Mountain grasslands
FRES44 Alpine
K008 Lodgepole pine-subalpine forest
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K017 Black Hills pine forest
K018 Pine-Douglas-fir forest
K022 Great Basin pine forest
K023 Juniper-pinyon woodland
K024 Juniper steppe woodland
K037 Mountain-mahogany-oak scrub
K038 Great Basin sagebrush
K050 Fescue-wheatgrass
K051 Wheatgrass-bluegrass
K052 Alpine meadows and barren
K055 Sagebrush steppe
K056 Wheatgrass-needlegrass shrubsteppe
K063 Foothills prairie
101 Bluebunch wheatgrass
102 Idaho fescue
106 Bluegrass scabland
107 Western juniper/big sagebrush/bluebunch wheatgrass
109 Ponderosa pine shrubland
110 Ponderosa pine-grassland
302 Bluebunch wheatgrass-Sandberg bluegrass
304 Idaho fescue-bluebunch wheatgrass
314 Big sagebrush-bluebunch wheatgrass
315 Big sagebrush-Idaho fescue
316 Big sagebrush-rough fescue
401 Basin big sagebrush
402 Mountain big sagebrush
403 Wyoming big sagebrush
406 Low sagebrush
407 Stiff sagebrush
412 Juniper-pinyon woodland
415 Curlleaf mountain-mahogany
420 Snowbrush
Onespike oatgrass is probably top-killed by fire.
Onespike oatgrass is not referred to as an important forage grass in available literature. Livestock graze the succulent basal herbage of onespike oatgrass in California, but the plant is not abundant enough to be considered outstanding forage [31]. The succulent bases are also very attractive to rodents, especially pocket gophers [33]. In the Blue Mountains of Oregon, onespike oatgrass is considered a secondary species, but produces valuable forage on harsh scabland sites not suitable to bluebunch wheatgrass [33].
Onespike oatgrass is present in numerous grassland, sagebrush (Artemisia spp.), mountain brush, quaking aspen (Populus tremuloides)-Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa), and lodgepole pine (P. contorta) habitat types and plant communities [27,37,40,44].
Plants commonly growing in association with onespike oatgrass include the following: big sagebrush (A. tridentata), stiff sagebrush (A. rigida), low sagebrush (A. arbuscula), shrubby cinquefoil (Dasiphora floribunda), antelope bitterbrush (Purshia tridentata), common snowberry (Symphoricarpos albus), sticky geranium (Geranium viscosissimum), arrowleaf balsamroot (Balsamorhiza sagittata), western yarrow (Achillea millefolium), lupine (Lupinus spp.), pussytoes (Antennaria spp.), biscuitroot (Lomatium spp.), rough fescue (Festuca altaica), Idaho fescue (F. idahoensis), bluebunch wheatgrass (Pseudoroegneria spicata), needle-and-thread grass (Hesperostipa comata), prairie
Junegrass (Koeleria macrantha), bottlebrush squirreltail (Elymus elymoides), and Sandberg bluegrass (Poa secunda) [6,22,30,36,45].
Classifications describing plant communities in which onespike oatgrass is a dominant or codominant species are as follows:
Habitat characteristics of the Silver Lake mule deer range [7]
Natural vegetation of Oregon and Washington [11]
Plant associations of the Fremont National Forest [19]
Plant associations of the Wallowa-Snake Province: Wallowa-Whitman National Forest [22]
In western Montana, onespike oatgrass did not increase in biomass but appeared larger and more vigorous on sites where spotted knapweed (Centaurea maculosa) had been controlled with herbicides [4].
Onespike oatgrass shows productive regrowth after fall rains, making it dependable fall forage on bluebunch wheatgrass sites in the Blue Mountains of northeastern Oregon. However, it is susceptible to damage from frost heaving, and is often winter-killed on exposed sites [33].
Onespike oatgrass response to grazing varies with location. It dominates ridgetop communities in the Blue Mountains, where severe overgrazing has basically eliminated deep-soil bunchgrasses because of reduced moisture retention [20]. Onespike oatgrass has responded as a 'decreaser' to grazing in Sandberg bluegrass scablands of the Blue Mountains of eastern Oregon and southeastern Washington and in sagebrush/bunchgrass types within the central Oregon pumice zone [13,40]. Conversely, it is described as an 'increaser' on foothill and mountain grassland sites in Montana and the Shoshone National Forest in Wyoming [30,37]. Volland [40] also refers to onespike oatgrass as a 'palatable increaser' on ponderosa pine/shrub/Idaho fescue sites within the central Oregon pumice zone.
Compared to other grasses, onespike oatgrass is rated "fair" in energy value and 'poor' in protein value [8].
The palatability of onespike oatgrass to livestock and wildlife species
has been rated as follows [8]:
MT UT WY
Cattle Fair Good Fair
Domestic sheep Fair Fair Fair
Horses Good Good Fair
Pronghorn ---- Poor Poor
Elk Poor Good Good
Mule deer Poor Fair Poor
White-tailed deer ---- ---- Poor
Small mammals ---- Fair ----
Small nongame birds ---- Poor ----
Upland game birds ---- Fair ----
Waterfowl ---- Poor ----
In the Gallatin National Forest of southwestern Montana, onespike oatgrass was a dominant species on a big sagebrush-grassland site prior to a spring prescribed fire. It increased in basal cover in the following summer [3,28].
Within a Sandberg bluegrass-onespike oatgrass plant association on the Wallowa Whitman National Forest, onespike oatgrass declined in coverage in postfire year 1 on 'very lightly burned' ridgetop sites. It was not determined by the author whether this loss in cover was directly related to fire or if the decline should be attributed to soil moisture loss or grazing by elk [23].
Onespike oatgrass was present in postfire years 1 and 2 on ponderosa pine plots following the 1988 Red Bench Fire in Glacier National Park, Montana [42,43].
On ponderosa pine and Douglas-fir communities in the Blue Mountains
of northeastern Oregon, onespike oatgrass cover and frequency in postfire year
4 were higher on prescribed burned sites than on thinned, thinned-and-burned,
or unburned control sites. Onespike oatgrass was determined to be an indicator
species for burned sites (P≤0.05). For further information
on the effects of thinning and burning treatments on onespike oatgrass and
48 other species, see the Research Project Summary of Youngblood and
others' [46] study.
Little information on the regenerative processes of onespike oatgrass is available in the literature.
Danthonia species reproduce by seed and tillering from the base [8,15,35,39,41]. Spikelets located in the axils of the lower leaves of onespike oatgrass are self-fertilizing [31,44].
2 Cascade Mountains
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
Onespike oatgrass is referred to as a climax species on thin soil scablands of the Intermountain Pacific Northwest, where shallow soil depths and bedrock limit the establishment of deeper-rooted plants. In the same region, onespike oatgrass is an invader on deep-soil sites dominated by fescues (Festuca spp.) where moisture retention has been diminished by overgrazing [21]. Onespike oatgrass has also been found on disturbed sites such as trail edges in ponderosa pine forests of eastern Washington and northern Idaho [6].
Johnson and Simon [22] report that onespike oatgrass is a principal indicator species of scabland communities of the Wallowa-Whitman National Forest. It is present in mid- to late-seral stages on moist microsites in bluebunch wheatgrass-Sandberg bluegrass plant associations, as well as early to late seres of stiff sagebrush/Sandberg bluegrass associations. Within this study area, onespike oatgrass often colonizes areas downslope from water sources, where soil moisture is retained for longer periods in the summer. It has been observed to decline with disturbance that increases bare ground. The authors distinguish Sandberg bluegrass-onespike oatgrass plant associations in this region, but are speculative as to whether these sites are climax or a result of severe site degradation of Idaho fescue-prairie
Junegrass communities.
The currently accepted scientific name of onespike oatgrass is Danthonia unispicata (Thurb.) Munro ex Macoun (Poaceae) [5,14,24,44].
Onespike oatgrass has low to moderate potential for erosion control and short-term to long-term revegetation projects [8]. In particular, low sagebrush/Sandberg bluegrass-onespike oatgrass plant associations in the Fremont National Forest of Oregon are usually found on very rocky soils typically saturated during winter and spring, making revegetation on these sites impractical [19]. The same information is reported for Sandberg bluegrass/onespike oatgrass associations in the Wallowa-Whitman National Forest [22].
Danthonia unispicata is a species of grass known by the common name onespike oatgrass, or onespike danthonia.
It is sometimes treated as a variety of Danthonia californica, to which it is similar. It is native to western North America, where it grows in several types of habitat, including grassland and open areas in mountain forests.
It is a perennial bunchgrass growing in clumps 10 to 30 centimeters tall, with very hairy, rolled leaves. The inflorescence bears a single spikelet, or sometimes up to four spikelets.
Danthonia unispicata is a species of grass known by the common name onespike oatgrass, or onespike danthonia.
It is sometimes treated as a variety of Danthonia californica, to which it is similar. It is native to western North America, where it grows in several types of habitat, including grassland and open areas in mountain forests.
It is a perennial bunchgrass growing in clumps 10 to 30 centimeters tall, with very hairy, rolled leaves. The inflorescence bears a single spikelet, or sometimes up to four spikelets.
