SPECIES: Leymus ambiguus
Plants database provides a distributional map of
FRES21 Ponderosa pine
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES38 Plains grasslands
STATES/PROVINCES: (key to state/province abbreviations)
The following classifications identify Colorado wildrye as a plant community dominant:
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 . 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 .
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 . Spikelets bear 2 to 10 flowers [10,13].
Colorado wildrye occasionally produces short rhizomes [10,21].
RAUNKIAER  LIFE FORM:
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" , producing approximately 390 seeds per plant. There are approximately 6,875 seeds per pound (243 seeds/gram) .
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 .
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 . McCarty  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 .
Colorado wildrye occasionally reproduces vegetatively from rhizomes [10,21,28].
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 . In Colorado where it is most prevalent, Colorado wildrye grows from 5,200 to 8,500 feet (1,585-2,590 m) . Soils are usually shallow and coarse-textured , though Colorado wildrye can grow in light sand to heavy clay soil .
Self-perpetuating stands of Colorado wildrye are indicative of climax conditions on rocky, xeric grassland sites along the Colorado Front Range .
Colorado wildrye growth ends in mid-September. Seeds are disseminated in early to mid-September .
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 |
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (40**) [39,45]|
|plains grasslands||Bouteloua spp.||< 35 [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||< 35 |
|wheatgrass plains grasslands||Pascopyrum smithii||< 5-47+ [29,31,44]|
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to > 200 |
|pinyon-juniper||Pinus-Juniperus spp.||< 35 |
|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.||< 35 to < 200 |
Palatability/nutritional value: McCarty  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 . 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 .
No information is available on this topic.
VALUE FOR REHABILITATION OF DISTURBED SITES:
No information is available on this topic.
No information is available on this topic.
OTHER MANAGEMENT CONSIDERATIONS:
Field trials have demonstrated that Colorado wildrye has high survivability and forage production potential in the eastern Central Great Plains, perhaps indicating its usefulness in livestock production .
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