Tridens muticus, slim tridens
Sullivan, Janet. 1992. Tridens muticus, slim tridens. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/trimut
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| Plants | ||||
| TRIMUT | slim tridens | Tridens muticus | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Tridens | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
Taxonomy
The accepted scientific name for slim tridens is Tridens muticus (Torr.) Nash. Recognized varieties are [9,11]:
- Tridens muticus (Torr.) Nash var. elongatus (Buckl.) Shinners
- Tridens muticus (Torr.) Nash var. muticus [9,11]
Synonyms
- Triodia mutica (Torr.)Scribn.
- Tricuspis mutica Torr.
- Tridentopsis mutica (Torr.) P.M. Peterson
- Sieglingia mutica (Torr.) Kuntze
Other Common Names
None
General Distribution
Slim tridens occurs through much of the southwestern United States, from California to the southern Great Plains, eastern Kansas, Oklahoma, and Texas south to central Mexico. It is widely distributed in the Chihuahuan and Sonoran deserts [9,24,31].
States and Provinces
- United States: AR AZ CA CO KS NV NM OK TX UT
- Mexico
Site Characteristics
Slim tridens occurs on dry plains, gravelly slopes, canyons and rocky hills up to 6,000 feet (1,829 m) [15,24]. It is adapted to well-drained, calcareous and rocky, sandy or clayey soils [9,20,24,32]. It tends to reach higher densities on the slightly wetter sites, such as elevations between 4,220 and 5,200 feet (1,286 and 1,585 m) [6].
Plant Communities
See the Appendix for a list of plant associations and cover types in which slim tridens occurs.
Common shrub associates not listed as cover types include: creosotebush (Larrea tridentata), wavyleaf oak (Quercus undulata), gray oak (Q. grisea), one-seed juniper (Juniperus monosperma), lechuguilla agave (Agave lechuguilla), smooth sotol (Dasylirion leiophyllum), Opuntia spp., and catclaw mimosa (Mimosa biuncifera) [3,17,25,28,32].
Other common associates (forbs and grasses) include skeleton goldeneye (Viguiera stenoloba), hairy grama (Bouteloua hirsuta), sideoats grama (B. curtipendula), threeawn (Aristida spp.), hairy tridens (Tridens pilosum), and curly leaf muhly (Muhlenbergia setifolia) [3,17,25,28,32].
Slim tridens plants with brushpea (Genistidium dumosum) in Texas.
Botanical Description
Slim tridens is a caespitose, stoloniferous, perennial grass, 8 to 30 inches (20-80 cm) tall. The bunches are usually narrow, not more than 3 or 4 inches (7 or 10 cm) in diameter [12,15,20]. It is considered a warm-season grass and exhibits C4 photosynthesis, which is adaptive for high temperatures and drought conditions [16,22].
Slim tridens plant.
Raunkiaer Life Form (Raunkiaer 1934)
- Geophyte
Seasonal Development
Slim tridens is a warm-season grass, beginning growth early in spring (late March in New Mexico) and actively growing through the summer, but with most growth in late spring. Two periods of flowering occur: from April to May and then again September to October. Seed heads are formed 3 to 5 weeks later [1,15,16,24].
Regeneration Processes
Slim tridens perennates from a shallow rhizome. Vegetative reproduction occurs through production of stolons [15]. Slim tridens also reproduces by seed. Seed collected for restoration project seed mixes resulted in a germination rate (without any attempt at stratification, etc.) of 19.8 percent after 14 days [30].
Slim tridens in fruit.
Successional Status
Facultative Seral Species
In a study of secondary succession on plots denuded by mechanical disturbance, Gehlbach [7] listed slim tridens as dominant in undisturbed plots. It occurred on disturbed plots only after three growing seasons, and it increased when cattle grazing was excluded from the site. Conversely, other authors have listed it as an increaser on cattle-grazed sites [3,20,23].
Immediate Fire Effects
A moderately hot fire will kill the aboveground portions of slim tridens, but survival of the rhizomes is usually good. Extremely hot fires will cause much more damage, especially among thin grasses not well protected by the buildup of vegetative material [17].
Postfire Regeneration Strategy (Stickney 1989)
- Rhizomatous herb, rhizome in soil
- Ground residual colonizer (on-site, initial community)
Fire Adaptations
Slim tridens perennates from rhizomes that are deep enough in the soil to resist damage by all but the most extreme fires. The types of habitats in which it occurs are not usually subject to such extreme fires because the fuel loading is usually low, and sparse grasses are often the main carriers of fire [17].
Plant Response to Fire
Perennial grasses in general undergo rapid postfire recovery and are usually improved as forage. Three years after a wildfire, slim tridens occurred in abundance with other grasses [17]. In a study to reduce shrub cover on a site invaded by redberry juniper, slim tridens showed no significant difference in cover value in the first two growing seasons after the shrub layer was chained then burned [28]. In other words, slim tridens was neither damaged nor improved by the fire.
Fire Regimes
For fire regime information, search FEIS for this species by entering the species name or acronym on the home page and selecting “Fire Regime” as the publication type.
Fire Management Considerations
No entry.
Federal Status
None
Other Status
No entry.
Importance to Wildlife and Livestock
Slim tridens is palatable and moderately nutritious. It is eaten by all classes of livestock, mule deer and other herbivores, and collared peccary but is too scattered and low in abundance to be an important forage species [2,12,15,18,31]. Seeds are a source of food for rodents and birds [20].
Palatability and Nutritional Value
Huston and others [13] reported the nutritional value of slim tridens as follows:
| Nutrient | Content (%) |
|---|---|
| Ash | 7–12 |
| Phosphorus | 0.09–0.30 |
| Protein | 6–13 |
| Digestible organic matter | 36–57 |
Fudge and Fraps reported similar levels for slim tridens (slender triodia) [5].
Cover Value
No entry.
Value for Rehabilitation or Restoration of Disturbed Sites
No entry.
Other Uses
No entry.
Other Management Considerations
In general, dryland range sites are easily degraded by overgrazing, which decreases incidence of fire and allows woody species to invade [1]. Steuter [28] reported that perennial grass production on sites invaded by redberry juniper (Juniperus pinchotii) is less than half that of sites that are controlled for shrub invasion. McPherson and Wright [23] reported an inverse relationship between pinyon (Pinus spp.) or juniper (Juniperus spp.) and herb production (as pinyon or juniper cover increases, herb production decreases), and that in closed canopy stands, junipers can exclude all herbaceous vegetation. In a related study of vegetative zonation around redberry juniper, slim tridens occurred at least 3.4 feet (1 m) from the edge of the canopy [22].
Slim tridens is not usually a major component of grasslands but may contribute up to 10 to 15 percent of the total production on some sites [20]. Gehlbach [6,7] and Blydenstein [2] reported that slim tridens increased in importance on study sites where grazing was excluded, which is in contrast to reports that slim tridens increases in response to grazing [3,20,23]. According to Leithead [20], abundance of slim tridens indicates fair to poor range condition.
As a "warm-season", C4 grass, slim tridens has its highest rate of carbohydrate storage during autumn; therefore, defoliation in the fall can contribute to winter-kill and cause loss of vigor during spring regrowth. It is recommended that pastures or ranges with an abundance of such grasses be grazed during the winter and spring [16,22].
Slim tridens is not considered a management species due to its scattered distribution and low importance value [6,7,12,18,20].
Table A1— Forest and range ecosystems, Bureau of Land Management (BLM) physiographic regions, Kuchler plant associations, Society for American Foresters (SAF) forest cover types, and Society for Rangeland Management (SRM) rangeland cover types in which this species occurs.
Forest and Range Ecosystems (Garrison et al. 1977)
- FRES29 Sagebrush
- FRES30 Desert shrub
- FRES31 Shinnery
- FRES32 Texas savanna
- FRES33 Southwestern shrubsteppe
- FRES35 Pinyon - juniper
- FRES40 Desert grasslands
BLM Physiographic Regions (Bernard and Brown 1977)
- 6 Upper Basin and Range
- 7 Lower Basin and Range
- 11 Southern Rocky Mountains
- 12 Colorado Plateau
- 13 Rocky Mountain Piedmont
- 14 Great Plains
Kuchler Plant Associations (Kuchler 1964)
- K023 Juniper - pinyon woodland
- K027 Mesquite bosque
- K038 Great Basin sagebrush
- K041 Creosotebush
- K042 Creosotebush - bursage
- K043 Paloverde - cactus shrub
- K044 Creosotebush - tarbush
- K053 Grama - galleta steppe
- K054 Grama - tobosa prairie
- K057 Galleta - three-awn shrubsteppe
- K058 Grama - tobosa shrubsteppe
- K059 Trans-Pecos shrub savanna
- K060 Mesquite savanna
- K061 Mesquite - acacia savanna
- K071 Shinnery
- K084 Cross Timbers
- K085 Mesquite - buffalograss
- K086 Juniper - oak savanna
- K087 Mesquite - oak savanna
SAF Cover Types (Eyre 1980)
- 66 Ashe juniper - redberry (Pinchot) juniper
- 67 Mohrs ("shin") oak
- 68 Mesquite
- 220 Rocky Mountain juniper
- 238 Western juniper
- 239 Pinyon - juniper
- 240 Arizona cypress
- 241 Western live oak
- 242 Mesquite
SRM Rangeland Cover Types (Shiflet 1994)
- No entry
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