SPECIES: Sporobolus flexuosus


SPECIES: Sporobolus flexuosus

Taylor, Jennifer L. 1999. Sporobolus flexuosus. 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/ [].




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mesa dropseed


The currently accepted name of mesa dropseed is Sporobolus flexuosus (Thurb.) Rydb. (Poaceae) [20,26,27,45,46].




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SPECIES: Sporobolus flexuosus

Mesa dropseed occurs from western Texas and southeastern Colorado to southern Utah, southern Nevada, eastern California, Arizona, and New Mexico. It also occurs in northern Mexico [20,23,27,45,46].

FRES30  Desert shrub
FRES33  Southwestern shrubsteppe
FRES35  Pinyon-juniper
FRES40  Desert grasslands



 4  Sierra Mountains
 5  Columbia Plateau
 6  Upper Basin and Range
 7  Lower Basin and Range
12  Colorado Plateau
13  Rocky Mountain Piedmont
14  Great Plains
K023  Juniper-pinyon woodland
K027  Mesquite bosque
K039  Blackbrush
K040  Saltbush-greasewood
K041  Creosotebush
K044  Creosotebush-tarbush
K057  Galleta-threeawn shrubsteppe
K058  Grama-tobosa shrubsteppe
 68  Mesquite
242  Mesquite
239  Pinyon-juniper
211  Creosotebush scrub
408  Other sagebrush types
412  Juniper-pinyon woodland
501  Saltbush-greasewood
504  Juniper-pinyon pine woodland
505  Grama-tobosa shrub
508  Creosotebush-tarbush
701  Alkali sacaton-tobosagrass
702  Black grama-alkali sacaton

Mesa dropseed is a component of desert scrub, shrub, grassland, sagebrush (Artemisia spp.) and pinyon-juniper (Pinus-Juniperus spp.) communities [3,46]. Wolters and others [47] placed it in the transition zone between desert scrub and desert grassland. Mesa dropseed is also a component of the mesquite-dropseed-broom snakeweed (Prosopis spp.-Sporobolus spp.-Gutierrezia sarothrae) and broom snakeweed-dropseed communities [4,9]. It has become a dominant grass species in fragmented black grama (Bouteloua eriopoda) stands [15] and is associated with soaptree yucca (Yucca elata) [6,32].


SPECIES: Sporobolus flexuosus

Cattle eat mesa dropseed all year long [32]. Use is heaviest during the summer when the plant is actively growing [16]. Black-tailed jackrabbits [9,44] and pronghorns also consume mesa dropseed [38].


Mesa dropseed becomes unpalatable and low in nutrition at maturity [16,21,35].


Mesa dropseed is lowest in protein during November to April (5%) and averages 7% during May to October. Calcium is highest from March to December (0.25%), with a peak May through August (0.35-0.45%), and lowest in January and February (< 0.2%) [32]. Mesa dropseed does not provide much forage in the early spring, because the first leaves are short and protected by the culms of previous years [15].

The nutritional content (%) of fresh mesa dropseed in mid-bloom is as follows [31]:

Ash   2.20
Crude fiber 13.50
Ether extract   0.60
N-free extract 15.60
Protein   3.10
Calcium   0.12
Phosphorus   0.06
Total Digestible Nutrients
     Cattle 22.40
     Domestic sheep 22.20


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Mesa dropseed is important in depleted stands of black grama. It stabilizes the loose, sandy soils giving the slower-growing black grama time to revegetate [30,33,35,46].


Native Americans used mesa dropseed seeds as food [27].


The response of mesa dropseed, measured by total nonstructural carbohydrates (TNC), to the season of defoliation was studied in southern New Mexico. After 3 years, 65% defoliation decreased TNC levels and crown diameter. Productivity during the following year was reduced when plants were clipped during flowering. Mesa dropseed can withstand heavier defoliation prior to flowering than during the rest of the growing season. If it is being continuously grazed, intensity should be < 65% during the growing season [30]. Holechek and others [22] found that removal of 1/3rd of current year annual growth was practical.

Mesa dropseed usually increases with the control of honey mesquite (Prosopis glandulosa var. glandulosa) [11,17]. Herbel and Gould [18] found removing at least 40% removal of honey mesquite produced greatest increases in mesa dropseed.

Mesa dropseed survives long droughts with grazing [7] and can reduce grazing stress on black grama during the growing season [2]. Adjusting grazing regimes to the amount and timing of rainfall can prevent overgrazing of mesa dropseed [15].


SPECIES: Sporobolus flexuosus

Mesa dropseed is a warm-season, native, perennial bunchgrass. It is short-lived (4-5 years) and sometimes grows as an annual [2,5,7,14,21,36,41,46,49]. Mesa dropseed has long culms (11.8-39.0 inches (30-100 cm)) with many leafy blades and coarse roots [5,7,14]. Dwyer and DeGarmo [10] found that roots decrease in biomass from top to bottom at 1/3rd field capacity and were better distributed as soil moisture decreased. Sporobolus spp. have small seeds (0.04-0.12 inch (0.1-0.3 mm)) [20].




Mesa dropseed reproduces from seed [5,15,33,46] that fall from the parent plant and can be wind blown [8,20,34]. The seeds have a hard seed coat that must be punctured before good germination occurs [23]. New culms or tillers originate from basal buds below the ground level and occasionally from a bud at an elevated node [15]. Development is quick during periods of adequate moisture and high night temperatures [7]. There is an almost immediate response to water, especially when soil water is supplied below 3.9 inches (10 cm) [15]. Mesa dropseed usually does not achieve maturity in an unbroken period. During periods of drought, it goes into a dormant stage [7]. New seedlings establish in open areas and under shrubs [30,34].


Mesa dropseed occurs mainly in dry areas with mean annual precipitation of 12 inches (300 mm) or less; it can survive in areas with as little as 6 to 7 inches (150-180 mm) mean annual precipitation [41,46]. It occurs on well-drained sand, sandy loams, loamy sands and gravelly soils [3,7,15,29].


Daniel and others [9] classified mesa dropseed as a mid- and late-seral species. Bridges [2] placed it just below the climax stage of black grama and Valentine [43] included it in the climax vegetation of the sandy soils on the New Mexico State University College Ranch, along with black grama and spike dropseed (Sporobolus contractus).


Mesa dropseed greens up during the spring and again in late fall if moisture is adequate [19]. New culms appear in March and flowering starts 4 to 5 days after inflorescence elongation begins [15]. Mesa dropseed blooms from September to November [8,21,46].


SPECIES: Sporobolus flexuosus

Desert grasslands with mesa dropseed were probably characterized by frequent fire. Kaib and others [25] studied the fire scar data of Apache pine (Pinus engelmannii) and Arizona pine (P. ponderosa var. arizonica) to determine the historic fire frequency of the Madrean Province in southern Arizona and New Mexico and northern Sonora and Chihuahua. Reconstructing intercanyon fire occurrences provided an estimate of the fire return interval of the adjacent semidesert grasslands. They gave a conservative estimate of every 4 to 8 years, and estimated that the actual fire return interval in semidesert grassland was closer to every 4 years.

Mesa dropseed is found in plant communities characterized by both long and short fire-return intervals. The dominants in plant communities in which mesa dropseed occurs are listed below. Refer to the FEIS species report for information on fire ecology in the following communities:

Fourwing saltbush (Atriplex canescens)
Black grama (Bouteloua eriopoda)
Creosotebush (Larrea tridentata)
Colorado Pinyon (Pinus edulis)
Honey mesquite (Prosopis glandulosa var. glandulosa)
Soaptree yucca (Yucca elata)

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".


Tussock graminoid


SPECIES: Sporobolus flexuosus

Mesa dropseed is damaged by fire [48], but its susceptiblity relative to other grasses, and its period of recovery, are poorly understood. Research is badly needed on fire's effects on mesa dropseed.


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Prescribed fire can be used to control the invasion of broom snakeweed, creosotebush, and young mesquite. Since shrub density in these communities is often low, abundance of mesa dropseed and other grasses must be adequate to carry a fire [48].

Sporobolus flexuosus: References

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2. Bridges, J. O. 1941. Reseeding trials on arid range land. Bulletin 278. Las Cruces, NM: New Mexico State University, Agricultural Experiment Station. 48 p. [5186]

3. Buffington, Lee C.; Herbel, Carlton H. 1965. Vegetational changes on a semidesert grassland range from 1858 to 1963. Ecological Monographs. 35: 139-164. [3383]

4. Campbell, R. S. 1929. Vegetative succession in the Prosopis sand dunes of southern New Mexico. Ecology. 10(4): 392-398. [4466]

5. Campbell, R. S.; Bomberger, E. H. 1934. The occurrence of Gutierrezia sarothrae on Bouteloua eriopoda ranges in southern New Mexico. Ecology. 15(1): 49-61. [596]

6. Campbell, R. S.; Keller, J. G. 1932. Growth and reproduction of Yucca elata. Ecology. 13(4): 364-374. [5932]

7. Canfield, R. H. 1934. Stem structure of grasses on the Jornada Experimental Range. Botanical Gazette. 95: 636-648. [7175]

8. Correll, Donovan S.; Johnston, Marshall C. 1970. Manual of the vascular plants of Texas. Renner, TX: Texas Research Foundation. 1881 p. [4003]

9. Daniel, Alipayou; Holechek, Jerry; Valdez, Raul; [and others]. 1993. Jackrabbit densities on fair and good condition Chihuahuan Desert range. Journal of Range Management. 46(6): 524-528. [25013]

10. Dwyer, Don D.; DeGarmo, Harlan C. 1970. Greenhouse productivity and water-use efficiency of selected desert shrubs and grasses under four soil-moisture levels. Bulletin 570. Las Cruces, NM: New Mexico State University, Agricultural Experiment Station. 15 p. [4443]

11. Eve, Marlen D.; Peters, Albert J. 1996. Using high temporal resolution satellite data to access shrub control effectiveness. In: Barrow, Jerry R.; McArthur, E. Durant; Sosebee, Ronald E.; Tausch, Robin J., compilers. Proceedings: shrubland ecosystem dynamics in a changing environment; 1995 May 23-25; Las Cruces, NM. Gen. Tech. Rep. INT-GTR-338. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 88-94. [27034]

12. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]

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14. Gay, Charles W., Jr.; Dwyer, Don D. 1965. New Mexico range plants. Circular 374. Las Cruces, NM: New Mexico State University, Cooperative Extension Service. 85 p. [4039]

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19. Herbel, Carlton H.; Nelson, Arnold B. 1966. Species preference of Hereford and Santa Gertrudis cattle on a southern New Mexico range. Journal of Range Management. 19: 177-181. [5313]

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25. Kaib, Mark; Baison, Christopher H.; Grissino-Mayer, Henri D.; Swetnam, Thomas W. 1996. Fire history in the gallery pine-oak forests and adjacent grasslands of the Chiricahua Mountains of Arizona. In: Ffolliott, Peter F.; DeBano, Leonard F.; Baker, Malchus, B., Jr.; [and others], tech. coords. Effects of fire on Madrean Province ecosystems: a symposium proceedings; 1996 March 11-15; Tucson, AZ. Gen. Tech. Rep. RM-GTR-289. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 253-264. [28109]

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30. Miller, Richard F.; Donart, Gary B. 1979. Response of Bouteloua eriopoda (Torr.) Torr. and Sporobolus flexuosus (Thurb.) Rhbd. to season of defoliation. Journal of Range Management. 32(1): 63-67. [3974]

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47. Wolters, Gale L.; Loftin, Samuel R.; Aguilar, Richard. 1996. Changes in species composition along a Chihuahuan Desert scrub/desert grassland transition zone in central New Mexico. In: West, N. E., ed. Proceedings, 5th international rangeland congress symposium; 1995 July 23-28; Salt Lake City, UT. Denver, CO: Society for Range Management: 323-324. [27906]

48. Wright, Henry A. 1980. The role and use of fire in the semidesert grass-shrub type. Gen. Tech. Rep. INT-85. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 24 p. [2616]

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