Colorado Wildrye

Colorado wildrye

Colorado wildrye is rare in Nevada [24].
Special consideration status for Colorado wildrye was considered and rejected in Idaho [35].

More info for the term: caespitose

The following description of Colorado wildrye provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g. [10,13,41,42]).

Colorado wildrye is a native, loosely caespitose perennial [10,13,21,23] that forms culms 12 to 43 inches (30-110 cm) tall [10,13].

Colorado wildrye leaves are mostly basal [10,13,21] and may be flat [10,41,42] or involute [13,15]. Leaves are 0.04 to 0.24 inch (1-6 mm) wide [13,15] and glabrous to sparsely pubescent [10]. Compared with the morphologically similar Salina wildrye (L. salinus), Colorado wildrye tends to be more lush in appearance due to its abundant vegetative growth and leafy culms [10].

Colorado wildrye spikes are erect and reach 3 to 7 inches (8-17 cm) long and 0.08 to 0.24 inch (2-6 mm) wide [10,13]. Spikelets may be paired or solitary at each node [10,13,41,42] and are 0.4 to 0.9 inch (10-23 mm) long [13]. Spikelets bear 2 to 10 flowers [10,13].

Colorado wildrye occasionally produces short rhizomes [10,21].

Colorado wildrye grows primarily along the east slope of the Rocky Mountains, from Montana south through Wyoming, Colorado, and New Mexico [7,10,23]. It has also been reported in Idaho [35], Utah [23], and Nevada [24].

Plants database provides a distributional map of Colorado wildrye.

More info for the terms: fire regime, woodland

Fire adaptations: Review of the available literature yielded no information pertaining specifically to the fire ecology or adaptations of Colorado wildrye. Further study is needed to clarify the relationship between fire and Colorado wildrye. Basin wildrye (L. cinereus) is a morphologically similar species, though it occurs on somewhat different sites and has a wider distribution. Information on fire ecology and adaptations of basin wildrye can be found in the FEIS species summary; it is unknown to what extent this information can be applied to Colorado wildrye.

FIRE REGIMES: Fire return intervals for plant communities and ecosystems in which Colorado wildrye occurs are summarized below. Find further 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".

Community or Ecosystem Dominant Species Fire Return Interval Range (years) sagebrush steppe Artemisia tridentata/Pseudoroegneria spicata 20-70 [29] Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (40**) [39,45] plains grasslands Bouteloua spp. 29,44] curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1,000 [6,33] mountain-mahogany-Gambel oak scrub Cercocarpus ledifolius-Quercus gambelii < 35 to < 100 Rocky Mountain juniper Juniperus scopulorum 29] wheatgrass plains grasslands Pascopyrum smithii 29,31,44] Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to > 200 [3] pinyon-juniper Pinus-Juniperus spp. 29] Colorado pinyon Pinus edulis 10-400+ [17,19,25,29] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [3,8,27] mountain grasslands Pseudoroegneria spicata 3-40 (10**) [2,3] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [3,4,5] oak-juniper woodland (Southwest) Quercus-Juniperus spp. 29] *fire return interval varies widely; trends in variation are noted in the species review
**mean

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More info for the term: hemicryptophyte

RAUNKIAER [32] LIFE FORM:
Hemicryptophyte

Colorado wildrye is found on steep, rocky mountainsides [10,20,41,42] and other dry slopes [13,15,20]. It is often more common near the base of slopes than at the crest or middle of slopes [12,13]. Colorado wildrye occurs on all aspects but grows best on south-facing slopes [20]. In Colorado where it is most prevalent, Colorado wildrye grows from 5,200 to 8,500 feet (1,585-2,590 m) [14]. Soils are usually shallow and coarse-textured [20], though Colorado wildrye can grow in light sand to heavy clay soil [21].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover

SAF COVER TYPES [16]:





206 Engelmann spruce-subalpine fir

210 Interior Douglas-fir

220 Rocky Mountain juniper

237 Interior ponderosa pine

239 Pinyon-juniper

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

ECOSYSTEMS [18]:





FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES23 Fir-spruce

FRES29 Sagebrush

FRES34 Chaparral-mountain shrub

FRES35 Pinyon-juniper

FRES36 Mountain grasslands

FRES38 Plains grasslands

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, woodland

KUCHLER [26] PLANT ASSOCIATIONS:





K011 Western ponderosa forest

K012 Douglas-fir forest

K015 Western spruce-fir forest

K018 Pine-Douglas-fir forest

K021 Southwestern spruce-fir forest

K023 Juniper-pinyon woodland

K032 Transition between K031 and K037

K037 Mountain-mahogany-oak scrub

K038 Great Basin sagebrush

K055 Sagebrush steppe

K056 Wheatgrass-needlegrass shrubsteppe

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: cover, forb, woodland

SRM (RANGELAND) COVER TYPES [34]:




301 Bluebunch wheatgrass-blue grama

302 Bluebunch wheatgrass-Sandberg bluegrass

303 Bluebunch wheatgrass-western wheatgrass

304 Idaho fescue-bluebunch wheatgrass

309 Idaho fescue-western wheatgrass

314 Big sagebrush-bluebunch wheatgrass

315 Big sagebrush-Idaho fescue

320 Black sagebrush-bluebunch wheatgrass

321 Black sagebrush-Idaho fescue

322 Curlleaf mountain-mahogany-bluebunch wheatgrass

401 Basin big sagebrush

403 Wyoming big sagebrush

405 Black sagebrush

406 Low sagebrush

409 Tall forb

412 Juniper-pinyon woodland

413 Gambel oak

415 Curlleaf mountain-mahogany

416 True mountain-mahogany

417 Littleleaf mountain-mahogany

419 Bittercherry

420 Snowbrush

504 Juniper-pinyon pine woodland

509 Transition between oak-juniper woodland and mahogany-oak association

More info for the term: caespitose

Little information is available regarding the effect of fire on Colorado wildrye, though it is presumably top-killed by fire. Colorado wildrye typically forms small, loosely caespitose bunches that grow in close aggregation [7,21]. This growth form suggests that Colorado wildrye may burn quickly, with little heat transferred downward into the crown. Typically, other bunchgrasses that are morphologically similar have basal buds at or just below the surface that are not subjected to prolonged heating and survive to resprout [44]. The occasionally rhizomatous nature of Colorado wildrye [10,21] also suggests some resistance to fire mortality.

More info for the term: cover

Colorado wildrye has a low tolerance to grazing and generally rates low in palatability, except perhaps in early spring [30].

Palatability/nutritional value: McCarty [28] found that the starch and sugar content of Colorado wildrye roots and stem bases reaches a maximum immediately following current seasonal growth, declines slightly during the dormant period, and reaches minimum levels during the formative stages of shoot development. For initial growth of both roots and shoots, Colorado wildrye depends completely on stored carbohydrates for energy and building material. The manufacture of carbohydrates begins relatively quickly, but this carbohydrate is used as fast as it is manufactured. Carbohydrate storage only begins when growth rates decrease [28]. Carbohydrate reserves are therefore directly related to growth rates, decreasing during rapid growth and increasing during slow growth [28,43]; however, temperature and the availability of water and nutrients also affect the seasonal variation of carbohydrate reserves [43].

Cover value: No information is available on this topic.

More info for the terms: grassland, shrub

In Colorado, Colorado wildrye may dominate montane grassland communities or
codominate shrub communities with Wyoming big sagebrush (Artemisia tridentata
ssp. wyomingensis) [9]. Common associates in Rocky Mountain juniper
(Juniperus scopulorum)-big sagebrush (A. tridentata) communities include
wax currant (Ribes cereum), sulphur-flower buckwheat (Eriogonum umbellatum),
varileaf phacelia (Phacelia heterophylla), and Indian ricegrass (Achnatherum
hymenoides) [1,20].

The following classifications identify Colorado wildrye as a plant community
dominant:

Colorado [9,22]

More info for the term: graminoid

Graminoid

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Colorado wildrye growth ends in mid-September. Seeds are disseminated in early to mid-September [28].

More info for the term: xeric

Available literature does not address Colorado wildrye's response to fire. More research is needed regarding both fire effects and Colorado wildrye response. More is known about basin wildrye, a morphologically similar bunchgrass; however, the degree to which this information can be applied to Colorado wildrye is unknown. Basin wildrye is adapted to well-drained lowland and upland sites in the Great Basin, while Colorado wildrye is generally found on steep, xeric sites. For more information regarding fire effects on basin wildrye, see the FEIS species summary.

More info for the terms: graminoid, ground residual colonizer, herb, initial off-site colonizer, rhizome, tussock

POSTFIRE REGENERATION STRATEGY [37]:
Rhizomatous herb, rhizome in soil
Tussock graminoid
Ground residual colonizer (on-site, initial community)
Initial off-site colonizer (off-site, initial community)

More info for the terms: adventitious, fruit, meristem, phase, seed, xeric

Colorado wildrye reproduces both by seed [28,36] and vegetative growth [10,21,28].

Breeding system: No information is available on this topic.

Pollination: No information is available on this topic.

Seed production: Limited data indicate Colorado wildrye exhibits "strong seed habits" [30], producing approximately 390 seeds per plant. There are approximately 6,875 seeds per pound (243 seeds/gram) [36].

Seed dispersal: No information is available on this topic.

Seed banking: No information is available on this topic.

Germination: No information is available on this topic.

Seedling establishment/growth: Initial seedling establishment of Colorado wildrye is generally high due to high germination rates and rapid seedling growth. Final establishment, however, is reportedly low, perhaps due to the xeric nature of most sites [30].

The growth of perennial range grasses can be described in 2 phases. The 1st phase is defined by the growth of vegetative shoots which is accelerated until the maximum growth rate is reached, after which the rate of growth declines. During this interval the inflorescence is differentiated from the apical meristem, thus initiating the 2nd growth period. The growth of the flower stalks is also accelerated, though the growth rate declines as the fruit ripens and the plant reaches maturity [28]. McCarty [28] found that growth of Colorado wildrye flower stalks progresses very slowly at first, with heads appearing in mid- to late June. As growth of the flower stalks accelerates, the dry weight of the plant is also greatly increased. Increases in dry weight slow in conjunction with flowering and the production of fruit. In general, increases in dry weight lag behind height growth. Adventitious root growth occurs in late July and lasts approximately 2 weeks, followed by secondary shoot growth [28].

Asexual regeneration: Colorado wildrye occasionally reproduces vegetatively from rhizomes [10,21,28].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [11]:





6 Upper Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

(key to state/province abbreviations)
UNITED STATES CO ID MT NV NM UT WY

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More info for the terms: climax, grassland, xeric

Self-perpetuating stands of Colorado wildrye are indicative of climax conditions on rocky, xeric grassland sites along the Colorado Front Range [22].

Elymus ambiguus Vasey & Scribn. [13,15,24]

The currently accepted scientific name of Colorado wildrye is Leymus ambiguus
(Vasey & Scribn.) D.R. Dewey (Poaceae) [10,23,41,42].

Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome short and compact, stems close, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems mat or turf forming, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blade auriculate, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades glaucous, blue-green, or grey, or with white glands, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence simple spikes, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence single raceme, fascicle or spike, Inflorescence spikelets arranged in a terminal bilateral spike, Rachis dilated, flat, central axis to which spikelets are attached, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelets with 3-7 florets, Spikelets p aired at rachis nodes, Spikelets distichously arranged, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes shorter than adjacent lemma, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes awn-like, elongated or subulate, Glumes keeled or winged, Glumes 1 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma mucronate, very shortly beaked or awned, less than 1-2 mm, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-f id, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis hairy at apex.

Leymus ambiguus is a species of grass known by the common names Colorado wildrye and Rocky Mountain wildrye. It is native to the Rocky Mountains of the United States, growing mainly on rocky hillsides on the eastern slopes of the mountains in Colorado and New Mexico; it has also been reported from Utah. It is a climax species on the dry grasslands of the Colorado Front Range.

This perennial grass produces loose clumps of stems of about 60 centimetres (24 in) to 110 centimetres (43 in) high, each of which is about 1 millimetre (0.039 in) thick. It is sometimes rhizomatous. Most of the leaves are located around the bases of the stems. The inflorescence is up to about 17 centimeters long and has solitary or paired spikelets, each containing up to 7 to 10 flowers. The grass has been noted to produce about 390 seeds per plant. The seeds germinate well and the seedlings grow fast.