SPECIES: Leymus ambiguus
Choose from the following categories of information.
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 regimes for plant communities and ecosystems in which Colorado wildrye occurs are summarized below. For further information, see the FEIS summary of the dominant plant species.
|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 .
1. Alexander, Robert R. 1987. Classification of the forest vegetation of Colorado by habitat type and community type. Res. Note RM-478. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 14 p. 
2. Arno, Stephen F. 1980. Forest fire history in the Northern Rockies. Journal of Forestry. 78(8): 460-465. 
3. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. 
4. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. 
5. Arno, Stephen F.; Scott, Joe H.; Hartwell, Michael G. 1995. Age-class structure of old growth ponderosa pine/Douglas-fir stands and its relationship to fire history. Res. Pap. INT-RP-481. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 25 p. 
6. Arno, Stephen F.; Wilson, Andrew E. 1986. Dating past fires in curlleaf mountain-mahogany communities. Journal of Range Management. 39(3): 241-243. 
7. Atkins, Riley J.; Barkworth, Mary E.; Dewey, Douglas R. 1984. A taxonomic study of Leymus ambiguus and L. salinus (Poaceae: Triticeae). Systematic Botany. 9(3): 279-294. 
8. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. 
9. Baker, William L. 1984. A preliminary classification of the natural vegetation of Colorado. The Great Basin Naturalist. 44(4): 647-676. 
10. Barkworth, Mary E.; Atkins, Riley J. 1984. Leymus Hochst. (Gramineae: Triticeae) in North America: taxonomy and distribution. American Journal of Botany. 71(5): 609-625. 
11. 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. 
12. Brotherson, Jack D. 1999. Measured and inferred moisture gradient relationships across ecotone boundaries in shrub-dominated foothill communities. In: McArthur, E. Durant; Ostler, W. Kent; Wambolt, Carl L., compilers. Proceedings: shrubland ecotones; 1998 August 12-14; Ephraim, UT. Proceedings RMRS-P-11. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 40-48. 
13. Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, Noel H.; [and others]. 1977. Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 6. The Monocotyledons. New York: Columbia University Press. 584 p. 
14. 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. 
15. Dorn, Robert D. 1984. Vascular plants of Montana. Cheyenne, WY: Mountain West Publishing. 276 p. 
16. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
17. Floyd, M. Lisa; Romme, William H.; Hanna, David D. 2000. Fire history and vegetation pattern in Mesa Verde National Park, Colorado, USA. Ecological Applications. 10(6): 1666-1680. 
18. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
19. Gottfried, Gerald J.; Swetnam, Thomas W.; Allen, Craig D.; [and others]. 1995. Pinyon-juniper woodlands. In: Finch, Deborah M.; Tainter, Joseph A., eds. Ecology, diversity, and sustainability of the Middle Rio Grande Basin. Gen. Tech. Rep. RM-GTR-268. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 95-132. 
20. Hess, Karl; Alexander, Robert R. 1986. Forest vegetation of the Arapaho and Roosevelt National Forests in central Colorado: a habitat type classification. Res. Pap. RM-266. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 48 p. 
21. Hitchcock, C. Leo; Cronquist, Arthur; Ownbey, Marion. 1969. Vascular plants of the Pacific Northwest. Part 1: Vascular cryptogams, gymnosperms, and monocotyledons. Seattle, WA: University of Washington Press. 914 p. 
22. Johnston, Barry C. 1987. Plant associations of Region Two: Potential plant communities of Wyoming, South Dakota, Nebraska, Colorado, and Kansas. 4th ed. R2-ECOL-87-2. Lakewood, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Region. 429 p. 
23. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Available: North Carolina Botanical Garden. In cooperation with the Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service [2001, January 16]. 
24. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 3 volumes]. Dissertation. 
25. Keeley, Jon E. 1981. Reproductive cycles and fire regimes. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; [and others], technical coordinators. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 231-277. 
26. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. 
27. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. 
28. McCarty, Edward C. 1935. Seasonal march of carbohydrates in Elymus ambiguus and Muhlenbergia gracilis, and their reaction under moderate grazing use. Plant Physiology. 10: 727-738. 
29. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; [and others]. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-volume 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
30. Plummer, A. Perry; Christensen, Donald R.; Monsen, Stephen B. 1968. Restoring big-game range in Utah. Publ. No. 68-3. Ephraim, UT: Utah Division of Fish and Game. 183 p. 
31. Quinnild, Clayton L.; Cosby, Hugh E. 1958. Relicts of climax vegetation on two mesas in western North Dakota. Ecology. 39(1): 29-32. 
32. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
33. Schultz, Brad W. 1987. Ecology of curlleaf mountain mahogany (Cercocarpus ledifolius) in western and central Nevada: population structure and dynamics. Reno, NV: University of Nevada. 111 p. Thesis. 
34. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
35. Steele, Robert; Brunsfeld, Steven J.; Henderson, Douglass M.; [and others]. 1981. Vascular plant species of concern in Idaho. Bulletin No. 34. Moscow, ID: University of Idaho, College of Forestry, Wildlife and Range Sciences, Forest, Wildlife and Range Experiment Station. 161 p. 
36. Stevens, O. A. 1957. Weights of seeds and numbers per plant. Weeds. 5: 46-55. 
37. 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. 10 p. 
38. U.S. Department of Agriculture, National Resource Conservation Service. 2004. PLANTS database (2004), [Online]. Available: http://plants.usda.gov/. 
39. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. 
40. Vogel, Kenneth P.; Jensen, Kevin J. 2001. Adaptation of perennial Triticeae to the eastern central Great Plains. Journal of Range Management. 54(6): 674-679. 
41. Weber, William A. 1987. Colorado flora: western slope. Boulder, CO: Colorado Associated University Press. 530 p. 
42. Weber, William A.; Wittmann, Ronald C. 1996. Colorado flora: eastern slope. 2nd ed. Niwot, CO: University Press of Colorado. 524 p. 
43. White, Larry M. 1973. Carbohydrate reserves of grasses: a review. Journal of Range Management. 26(1): 13-18. 
44. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p. 
45. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505.