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Lycurus spp.

• INTRODUCTORY
• DISTRIBUTION AND OCCURRENCE
• BOTANICAL AND ECOLOGICAL CHARACTERISTICS
• FIRE ECOLOGY
• FIRE EFFECTS
• MANAGEMENT CONSIDERATIONS
• REFERENCES

INTRODUCTORY

AUTHORSHIP AND CITATION FEIS ABBREVIATION NRCS PLANT CODE COMMON NAMES TAXONOMY SYNONYMS LIFE FORM FEDERAL LEGAL STATUS OTHER STATUS
	R. E. Rosiere, Tarleton State University

Lycurus phleoides Kunth [4,35], common wolfstail
Lycurus setosus (Nutt.) CG Reeder [4,35,70], bristly wolfstail

Infrataxa:
Taxonomic recognition of wolfstail species is inconsistent. Recognition of L. setosus is relatively new and not entirely accepted. Welsh and others [71] suggest that the variable and somewhat inconsistent morphological differences between the Lycurus species do not warrant discrimination at the species level [71]. Florae from California [28], Arizona [36], New Mexico [43], and Utah [71] do not list L. setosus as part of their state flora, but the North American Flora [4] indicates that L. setosus occurs in each of those states. Harrington [27] describes L. phleoides in Colorado, but a later Colorado flora by Weber and Wittman [70] suggests that L. setosus was misidentified as L. phleoides in the earlier Colorado flora. Distribution maps presented in the Flora of North America [4] indicate that both L. phleoides and L. setosus occur in Colorado.

Given this confusion, wolfstail species are not distinguished throughout the majority of this review. The common name "wolfstail" is used when referring to species identified in the literature as either L. phleoides or L. setosus. The vast majority of literature cited in this review names L. phleoides as the species studied; however, the true identity of species identified as L. phleoides is suspect given the taxonomic treatment and species distributions presented by Reeder in these sources: [4,58]. According to Reeder, L. setosus is the more widely distributed of the wolfstail species [4,58], but only 3 studies cited in this review [16,47,55] name L. setosus as the plant investigated. In 1 of the 3 articles, Burgess [16] cited work by Canfield [18] and changed the L. phleoides name used by Canfield to L. setosus.

DISTRIBUTION AND OCCURRENCE

• GENERAL DISTRIBUTION
• HABITAT TYPES AND PLANT COMMUNITIES

Wolfstail is dominant or important in the following vegetation classifications:

• Arizona interior chaparral vegetation in central Arizona, Society for Range Management type 503 [61]

• blue grama-wolfstail grasslands on the Sevilleta National Wildlife Refuge of central New Mexico [50]

• Colorado pinyon-alligator juniper/gray oak (P. edulis-J. deppeana/Q. grisea)/wolfstail habitat types on the Gila National Forest

• Colorado pinyon-alligator juniper/Apache plume (Fallugia paradoxa)/wolfstail-bottlebrush squirreltail (Elymus elymoides) habitat types on the Gila National Forest [29]

BOTANICAL AND ECOLOGICAL CHARACTERISTICS

• GENERAL BOTANICAL CHARACTERISTICS
• RAUNKIAER LIFE FORM
• REGENERATION PROCESSES
• SITE CHARACTERISTICS
• SUCCESSIONAL STATUS
• SEASONAL DEVELOPMENT

Wolfstail is a tufted perennial grass. Plants can be compressed, erect, or widely spreading at the base [4,19,25,71]. Stems are fine and grow 8 to 24 inches (20-60 cm) tall [17,30,75]. Wolfstail is short lived. On the Santa Rita Experimental Range in southern Arizona, the oldest wolfstail plants were 9 years old [18].

Wolfstail has fine, stiff, mostly basal leaves. Leaf blades are flat to folded and typically measure 1.6 to 5 inches (4-13 cm) long and 1 to 3 mm wide [4,23,43]. Leaves sometimes have sharp, bristle-like tips [71]. The spike-like panicle is bristly, cylindrical, and resembles a wolf's tail. Panicles are typically 1.2 to 5.1 inches (3-13 cm) long, 3 to 8 mm long, and densely flowered [19,43,71]. Spikelets are paired and single flowered [19,75]. Glumes and lemmas are awned. Awns can measure up to 7 mm long [19,36]. Often the lower of the paired spikelets is staminate or sterile and the upper is bisexual; however, any spikelet may be fertile, staminate, or sterile. Paired spikelets are shed together [4,58]. Seed grains are spindle-shaped [4]. Wolfstail seeds collected from an ungrazed area in southeastern Arizona averaged 0.21 mg [56]. Wolfstail produces coarse, fibrous roots [67]. Rhizomes are lacking [27,67]. Descriptions of rooting depth and spread were not found in the reviewed literature.

Information on the reproductive biology of wolfstail is lacking. Both staminate and perfect flowers are produced, and flowers are primarily wind pollinated. Genetic studies of L. setosus revealed high levels of genetic variation similar to outcrossing plants [55].

Awns on the lemmas and glumes suggest that seed dispersal by animals is possible. Seed germination requirements are unknown.

Seed production: The number of seeds typically produced by wolfstail was not reported. Gay and Dwyer [23] report that seed production can be reduced by heavy grazing and that heavy grazing may eliminate local wolfstail populations.

Seed banking: Field reports of wolfstail seed longevity in the soil are lacking. On the Appleton-Whittell Research Ranch in southeastern Arizona, wolfstail emerged from a soil sample taken from a burned grama grassland. The density of seed was not reported, and soil samples were collected 1 month to 1 year after fire. Wolfstail did not emerge from soil samples collected from burned, nonnative, lovegrass (Eragrostis spp.)-dominated grasslands or unburned grama grasslands [47].

Wolfstail seeds stored indoors for 20 years failed to germinate after "standard germination tests". Seeds were collected on or near Arizona's Sierra Ancha Experimental Forest and were not protected from humidity or temperature extremes. No germination tests were conducted on newly collected seed [65].

Seedling establishment/growth: On the Santa Rita Experimental Range, wolfstail produced more seedlings on grazed than ungrazed sites, but seedlings survived better on ungrazed than grazed sites. Wolfstail produced an average of 6.2 and 3.1 seedlings/m²/year on grazed and ungrazed sites, respectively. First year survival was 30.7% on grazed and 50% on ungrazed sites. Seedling mortality was greatest in the first 2 years [18].

Vegetative regeneration: Because wolfstail is a bunchgrass, spread by tillers is likely. As of this writing (2008), however, vegetative regeneration was not documented.

Aspect: Wolfstail grows on a variety of exposures [67]. On the Gila National Forest, the Colorado pinyon-alligator juniper/gray oak/wolfstail habitat type is most common on southeastern and southwestern exposures, and the Colorado pinyon-alligator juniper/Apache plume/wolfstail-bottlebrush squirreltail habitat type is most common on northeastern exposures [29]. On New Mexico's Fort Stanton Experimental Ranch, wolfstail cover was greatest on the south side and lowest on the north side of oneseed junipers (J. monosperma) and Colorado pinyons [2].

Climate: The climate is semiarid to arid in wolfstail habitats. References consulted throughout this review showed that climates in wolfstail habitats varied somewhat by site and site condition class. Minimum and maximum temperatures and precipitation levels reported are specific to the location identified and based on a finite time period.

In southern Arizona, wolfstail occurs in Santa Cruz County where January minimum temperatures average 35 °F (1.7 °C), and June maximums average 90.3 °F (32.4 °C) [8]. In Sasabe, Arizona, annual precipitation ranged from 8 to 19.4 inches (200-490 mm) for a 13-year period. Droughts were common in May and June before the substantial summer rains [73]. Wolfstail habitats in central New Mexico's Sevilleta National Wildlife Refuge, average 9.6 inches (245 mm) of annual precipitation. Winter temperatures average 36 °F (2 °C), and summer temperatures average 88 °F (31 °C) [50].

In Marfa, Texas, August soil surface temperatures were highest on rolling grassland sites in "poor" rangeland condition. Soil surface temperatures reached 120 °F (49 °C) on the "poor" sites with sparse litter and vegetation cover. Sites in "good" condition had soil surface temperatures of 110 °F (43 °C), and rangeland sites in "excellent" condition had soil surface temperatures of 104 °F (40 °C)[40].

Elevation: Wolfstail is common at midelevation sites [25]. Wolfstail occurs from 1,900 to 11,000 feet (570-3,400 m) throughout the southwestern United States, which is a wider range than reported in the table below. Lycurus setosus occupies a broader range of elevations than L. phleoides [4].

Soils: Wolfstail grows on a variety of soils but typically grows best on sandy gravelly loams [67]. Wolfstail occurred on both granite and limestone soils in the Mule Mountains of Arizona, but cover and frequency were about twice as great on granite as on limestone [72]. On the Appleton-Whittell Research Ranch, wolfstail was common on upland mesa sites with fine-textured, rich, reddish-yellow soils but did not occur on limestone outcrops [9]. In Santa Cruz County, Arizona, wolfstail occurred on soils that had low pH and were low in available nitrates and/or potassium [52].

Shade: In New Mexico, wolfstail grew best in interspaces or at the edge of oneseed juniper and Colorado pinyon canopies [2,62], but on Arizona's Appleton-Whittell Research Ranch, wolfstail often grew within shrub canopies, especially yerba de pasmo (Baccharis pteronioides) canopies [9]. Tree and shrub canopy closure was likely different in the 2 studies and may have affected wolfstail distribution. On the Fort Stanton Experimental Ranch, wolfstail had much greater basal cover in interspaces than under the canopy of oneseed juniper and Colorado pinyon. Researchers suggested severe shading, decreased soil moisture, high litter concentrations, and/or allelopathic effects beneath the canopy likely restricted wolfstail growth [2]. In New Mexico wolfstail basal cover increased with increasing distance from oneseed juniper trunks. Canopy closure was at least 89% and litter depths were up to 1.7 inches (4.3 cm) adjacent to the trunk. At the edge, canopy cover was reduced by more than half, and litter depth was negligible. Wolfstail basal cover was significantly (P<0.0242) lower at the trunk than at the canopy edge. No wolfstail plants grew adjacent to the trunk, and at the canopy edge basal cover was at least 2.2% [62].

Grazing: The majority of studies show that wolfstail cover is greatest on ungrazed sites. Wolfstail abundance typically decreases as grazing duration and intensity increase. Judd [34] reported that heavy livestock grazing can eliminate wolfstail. Canfield [18] found that wolfstail was predominant on sites with light or no grazing on Arizona's Santa Rita Experimental Range. In Texas, wolfstail was described as increasing temporarily but later decreasing with heavy grazing. In Marfa, Texas, range condition was considered "excellent" and "good" when 5% and 10% of the composition was wolfstail, respectively. Grasslands that lacked wolfstail were in "poor" condition [40].

In Santa Cruz County, Arizona, wolfstail cover was significantly (P<0.05) greater on ungrazed than grazed grama grasslands. Grazed and ungrazed sites were compared 13 years after the construction of livestock exclosures [8]. Wolfstail cover was also greater on protected than grazed sites on the Appleton-Whittell Research Ranch. On Bald Hill, wolfstail cover was 1.9% one year after livestock removal and 2.6% sixteen years after livestock removal. Along the fence line of the Ranch, wolfstail cover was 1.1% on the grazed side and 1.8% on the protected side. Cover of plains lovegrass (E. intermedia) was 10 times greater on the protected side than on the grazed side of the fence line. Plains lovegrass may have interfered with wolfstail on the protected side [13].

On 6 of 8 rolling grassland sites on the Sonoita Plain of northern Santa Cruz County, wolfstail cover was greater on ungrazed than grazed sites. On the remaining 2 sites, wolfstail cover was greater on grazed than ungrazed plots [6]. On blue grama grasslands in south-central New Mexico, wolfstail cover decreased with increased cattle grazing duration regardless of continuous or short-duration grazing patterns [74].

Fire: Based on the few available fire studies in wolfstail habitats, an initial reduction in wolfstail abundance is typical after fire. However, recovery to prefire or unburned levels is common by the 2nd or 3rd postfire growing season regardless of the fire season, fire severity, or community type. For additional information on this topic, see Fire Effects.

SEASONAL DEVELOPMENT:
Most wolfstail growth occurs after summer rains [23,31]. Wolfstail flowers from July to October [4,36,43,75]. Seeds are likely dispersed in September or October [67].

FIRE ECOLOGY

• FIRE ECOLOGY OR ADAPTATIONS
• POSTFIRE REGENERATION STRATEGY

Fire regimes: Lightning, dry conditions, and fires are common in late spring or early summer in wolfstail habitats. In oak woodlands and savannas of the southwestern United States and northern Mexico, late spring and early summer lightning fires are common. In the Peloncillo Mountains of southern Arizona and New Mexico, fires are typical in June or early July before summer rains [24]. Before European settlement of the Great Plains, large fires probably occurred in drought years that followed 1 to 3 years of above-average precipitation, which resulted in an accumulation of fine fuel. When relative humidity was low and air temperatures and wind speeds were high, fires could easily spread many miles [69,76].

Fire frequency in wolfstail habitats was likely higher before European settlement of the Southwest. Based on the fire frequency in western and southeastern pine/grassland communities, personal experience, and the establishment and growth patterns of woody plants, researchers suggested that the presettlement fire frequency in level to rolling Great Plains grasslands was 5 to 10 years. In the Rolling Plains and Edwards Plateau of Texas, where topography is rough and dissected by breaks and rivers, fires probably burned less frequently at intervals of 15 to 30 years [69,76]. In a review of western pinyon-juniper communities, Wright and others [77] suggest that desert grassland fires every 10 to 30 years were likely before settlement. Fires at this frequency would have restricted the expansion of pinyon and juniper trees into grasslands.

The fire regime for wolfstail in the understory of pinyon-juniper communities is likely much more variable than that of grassland communities. Colorado pinyon-Utah juniper (J. osteosperma) woodlands in southern Colorado burned in stand-replacing fires at approximately 400-year or longer rotations. Low-severity surface fires were rare [22]. Fire frequency in Colorado pinyon-juniper communities is likely dictated by fuel loading and composition. When understory and overstory vegetation is sparse, fire spread is unlikely without extreme fire weather, and fire-free intervals are likely much longer than those in woodlands with a well-developed understory and/or high tree density. See Colorado pinyon for a more complete discussion on the fire regimes in Colorado pinyon-juniper habitats.

Heavy grazing and other early European land use activities likely decreased the fire frequency in southwestern wolfstail habitats. The cultivation of large land sections reduced fuel, and large herds of livestock, primarily cattle, reduced the abundance and continuity of fine fuels. In the Great Plains grasslands, cultivation has reduced fuel continuity and the potential for widespread fire [69,76]. In the southern Arizona counties of Pima, Santa Cruz, and Cochise, livestock numbered over 200,000 in the late 1800s and early 1900s. Livestock were likely concentrated on desert grasslands (Bahre 1991, cited in [45]). In oak woodlands and savannas in the southwestern United States and northern Mexico, decreased abundance of fine fuels through heavy livestock grazing reduced fire frequencies and increased woody species abundance [24]. Similar species composition changes are noted in a review of pinyon-juniper habitats. Researchers suggest that decreased fine fuel abundance through livestock grazing allowed pinyon and juniper trees to establish in grasslands that used to burn frequently enough to kill pinyon and juniper seedlings and other juveniles [77]. On the Fort Stanton Experimental Range, an April surface fire in a predominantly blue grama grassland killed all oneseed junipers that were less than 4 feet (1.2 m) tall. Colorado pinyons survived better, since tress less than 6 feet (1.8 m) tall were rare within the area before the fire [20].

A pattern of reduced fire frequency after European settlement is not evident in all southwestern wolfstail habitat types. Fire scars from Arizona cypress (Cupressus arizonica), Mexican pinyon (Pinus cembroides), and juniper in Big Bend National Park, Texas, indicated that fire frequencies did not differ before or after 1880. On average, woodland fires burned every 70 years. The range of fire-return intervals was 9 to 60 or more years for the 1780 to 1940 time period [48,49].

While decreased fire frequency with fuel reductions by heavy grazing is noted for many southwestern areas, the introduction, establishment, and recent spread of many annual and perennial nonnative grasses have increased the fire frequency in other areas. Nonnative grasses such as cheatgrass (Bromus tectorum), red brome (B. madritensis), Mediterranean grasses (Schismus spp.), and lovegrasses are possible in wolfstail habitats and have the potential to alter fuel loads and fire frequencies. Information on the effects of these and other nonnative species on fire regimes in the interior West is available in Chapter 8 of [59]. See Plant Response to Fire for a discussion of fire's potentially different effects on lovegrasses and wolfstail.

The following table provides fire regime information that may be relevant to wolfstail. Find further fire regime information for the plant communities in which these species may occur by entering the species' names in the FEIS home page under "Find Fire Regimes".

FIRE EFFECTS

• IMMEDIATE FIRE EFFECT ON PLANT
• DISCUSSION AND QUALIFICATION OF FIRE EFFECT
• PLANT RESPONSE TO FIRE
• DISCUSSION AND QUALIFICATION OF PLANT RESPONSE
• FIRE MANAGEMENT CONSIDERATIONS

A greenhouse study suggests that the loss of mycorrhizae from burned sites may decrease postfire wolfstail growth and increase postfire growth of neighboring lovegrasses. Researchers compared May-burned and unburned soils collected in southern Arizona. Mycorrhizal infection percentages were much lower on burned than unburned soils. Wolfstail seed in soils without mycorrhizae produced plants with lower shoot-to-root ratios and root biomass than those in soils with mycorrhizae. Within the 90-day study period, wolfstail plants in soils without mycorrhizae did not flower. The absence of mycorrhizae produced opposite effects on native and nonnative lovegrasses. Lovegrass growing without mycorrhizae produced greater shoot-to-root ratios and biomass and produced seed earlier than plants with mycorrhizae [53].

Increased presence of lovegrasses can affect wolfstail abundance. On the Appleton-Whittell Research Ranch, wolfstail cover was significantly greater (P<0.001) on semidesert grasslands dominated by native blue grama (5.9% wolfstail cover) than on those dominated by nonnative lovegrass (1.6% wolfstail cover) [7].

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
An initial reduction in wolfstail abundance is typical after fire. Very low wolfstail abundance is possible in the early postfire months [20]. However, in the limited number of fire studies in wolfstail habitats, recovery to prefire or unburned abundance was typical by the 2nd or 3rd postfire growing season [1,10,11,73]. Fire season or severity differences possibly important to the postfire wolfstail response were not evident from these few studies. Cover of wolfstail on burned sites was lowest 2.5 years after an early April, "low heat intensity" fire in a New Mexico blue grama grassland [20]. In the only study to compare fire severities, wolfstail recovered best and quickest on sites that burned with the lowest severity [73]. Given the desert and semidesert climate of wolfstail habitats, postfire moisture is likely important to postfire growth and reproduction. Fire effects on wolfstail are reported for desert grasslands, shrublands, and woodlands, but their geographic range includes only Arizona, New Mexico, and a small part of Texas, which represent only a portion of wolfstail's range.

Desert grassland fires: Wolfstail density had returned to prefire levels 2 years after a 12 June 1984 prescribed fire on a southeastern Arizona semidesert grassland [10,11].

During the postfire sampling period, the density of wolfstail decreased by nearly the same amount on unburned and burned sites. It was difficult to determine if the slight reduction in wolfstail density was caused by fire [10,11].

This study was part of an extensive of body of research on fire effects in semidesert grassland, oak savanna, and Madrean oak woodlands of southeastern Arizona. See the Research Project Summary of this work for more information on burning conditions, fires, and fire effects on more than 100 species of plants, birds, small mammals, and grasshoppers.

After a late-June wildfire near Sasabe, Arizona, wolfstail density exceed prefire density by the second postfire year on all burned sites. Fire "uniformity and intensity" were greatest on northern and lowest on eastern aspects [73].

Shrubland and woodland fires: Wolfstail frequency was similar on 3-year-old burned and similar unburned shrub communities in the Guadalupe Mountains of southern New Mexico and western Texas. Wolfstail frequency was greater on 6- to 7-year-old burned sites than on similar unburned sites. Lechuguilla (Agave lechuguilla), smooth-leaf sotol (Dasylirion leiophyllum), and Pinchot juniper (J. pinchotii) are characteristic of the shrublands. Of the sites sampled, 4 burned in June; the remainder burned in April, March, or August. Precipitation was near normal for all postfire years, except in the year before sampling, when drought conditions occurred [1].

Wolfstail cover was much lower on burned than unburned sites up to about 2.5 years after a "low heat intensity", mid-April fire in south-central New Mexico. The study area was dominated by blue grama with some Colorado pinyon and oneseed juniper. The fire burned when relative humidity was low, winds were warm, and soil, litter, and grass were dry. The fire spread 1,250 feet (381 m)/hour, and flames did not reach into tree crowns. The fuel load, estimated on similar unburned sites, was 738 lb/acre. Postfire precipitation was below normal in the first postfire year and above normal in the second, with most rainfall occurring throughout the growing season [20].

Wolfstail was listed as one of many species that occurred on burned sites after a mid-March wildfire in pinyon-oak-juniper woodlands and oak shrublands in Big Bend National Park. The fire burned after a 7-month drought when rainfall was about 3.9 inches (100 mm) less than average. Burned sites were visited one month and 18 months after fire [41]. Whether or not wolfstail was observed on one or both visits is unclear. Wolfstail abundance was not reported.

FIRE MANAGEMENT CONSIDERATIONS:
Wolfstail probably recovers quickly after most fires. However, the recovery of wolfstail following multiple fires is unknown. Additional information specific to fire season, fire severity, and repeated fire would improve the future management of wolfstail populations.

A 1993 review addresses potential hazards and provides guidelines for burning southern Great Plains grasslands. Head fires typically burn successfully, and control is straightforward when relative humidity is 25% to 40%, air temperatures are 70 to 75 °F (21-24 °C), and wind speeds exceed 8 miles (13 km)/hour. However, burning conditions may need adjusting for fuel volatility, topography, and desired fire severity [69].

MANAGEMENT CONSIDERATIONS

• IMPORTANCE TO WILDLIFE AND LIVESTOCK
• VALUE FOR REHABILITATION OF DISTURBED SITES
• OTHER USES
• OTHER MANAGEMENT CONSIDERATIONS

Deer/elk: On the Gila National Forest, the Colorado pinyon-alligator juniper/Apache plume/wolfstail-bottlebrush squirreltail habitat type receives moderate deer and low elk use [29].

Small mammals: Nearly all (97.1%) night survey sightings of white-sided jackrabbits occurred in mixed-grassland habitats from May to August in the Animas and Playas valleys of New Mexico. Grama, ring muhly (Muhlenbergia torreyi), buffalo grass (Buchloe dactyloides), and wolfstail dominated the grasslands [5].

Birds: It is likely that many bird species feed on wolfstail seeds. However, as of this writing (2008), information was only available for sparrows and wild turkeys. In captive feeding studies on wild-caught chipping sparrows and white-crowned sparrows, 8 chipping sparrows consumed 150 wolfstail seeds, and 1 white-crowned sparrow consumed 17 seeds [56]. Of 24 wild turkeys killed in October or November on southeastern Arizona's San Carlos Indian Reservation, 2 crops contained wolfstail seed heads [51].

Livestock: Cattle and domestic sheep consume wolfstail, but consumption is typically greater by cattle. On the Fort Stanton Experimental Ranch, the dry weight percentage of wolfstail in cattle diets ranged from a high of 19.2% in August to a low of 2.3% in April. For domestic sheep, the high was 8.2% in July and the low was 0.7% in January. There were 34.5 acres/AU in the year-round grazed area, which transitioned from of grama-galleta (Pleuraphis jamesii) grassland to oneseed juniper-Colorado pinyon woodland [64]. In another study on the Fort Stanton Experimental Ranch, wolfstail comprised a major portion of cattle diets during growing and dormant seasons in Colorado pinyon-juniper woodlands [37].

Palatability/nutritional value: Wolfstail is described as important, good to very good forage with moderate to high livestock palatability in the Southwest [23,32,34,36]. Humphrey [31] reported that wolfstail is most palatable during and just after summer rains.

Wolfstail is often most abundant on sites with minimal shrub cover and minimal grazing. In desert grasslands in the southern Chihuahuan Desert of Mexico, wolfstail cover was greatest on ungrazed sites where creosote bush (Larrea tridentata), the dominant shrub, and other shrubs had been controlled [44].

Lycurus spp.: REFERENCES

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