|Pinkflower hedgehog cactus. Photo courtesy of Wayne Scott Ray.|
Echinocereus fendleri var. bonkerae (Thornb. & Bonker) L. Benson, Bonker's hedgehog cactus
Echinocereus fendleri var. boyce-thompsonii (Orcutt) L. Benson, Boyce-Thompson hedgehog cactus
Echinocereus fendleri var. fasciculatus (Engelmann ex B.D. Jackson) N.P. Taylor [19,43], strawberry hedgehog cactus
Echinocereus fendleri var. fendleri (Engelmann) F. Seitz [1,2,12,18,19,20,30,53], Fendler's hedgehog cactus
Echinocereus fendleri var. kuenzleri (Castetter, Pierce & Schwerin) L. Benson [2,12,19,43], Kuenzler's hedgehog cactus
Echinocereus fendleri var. ledingii (Peebles) N.P. Taylor [19,43], Leding's hedgehog cactus
Echinocereus fendleri var. rectispinus (Peebles) L. Benson [1,2,3,12,18,19,20,30,43,53], right-angled spine hedgehog cactus
In this review, varieties are referred to by their common names, and "pinkflower hedgehog cactus" refers to the species as a whole. Of the varieties listed above, only Fendler's hedgehog cactus and right-angled spine hedgehog cactus are recognized as valid by all Echinocereus systematists (review by ).
There is disagreement over the taxonomic treatment of Kuenzler's hedgehog cactus . While some consider E. f. var. kuenzleri a synonym of E. f. var. fendleri, others suggest it is best treated as a distinct taxon, either E. f. subsp. kuenzleri  or E. f. var. kuenzleri [47,51]. Kuenzler's hedgehog cactus is treated as a distinct variety in this review.
Hybridization occurs in Echinocereus. Scarlet hedgehog cactus (E. coccineus) × pinkflower hedgehog cactus and kingcup cactus (E. triglochidiatus) × pinkflower hedgehog cactus hybrids are likely sterile . A varietal cross of pinkflower hedgehog cactus, Kuenzler's hedgehog cactus × Fendler's hedgehog cactus, may occur at the northwestern edge of Kuenzler's hedgehog cactus's range. Varietal hybrids of pinkflower hedgehog cactus are fertile (, Knight 2002, personal communication cited in ).SYNONYMS:
Bonker's hedgehog cactus is endemic to Arizona. It is most common in Gila County but also occurs in Pinal, Cochise, Graham, and Santa Cruz counties .
Boyce-Thompson hedgehog cactus is also endemic to Arizona, occurring in Coconino, Yavapai, Gila, Graham, and Pinal counties .
Strawberry hedgehog cactus occurs in Yavapi, Graham, Cochise, and Pima counties, Arizona, and in adjacent Sonora, Mexico [20,34]
Fendler's hedgehog cactus occurs in Arizona, New Mexico, southwestern Texas near the upper Pecos River, and northern Chihuahua. It has also been collected in Garfield County, Utah. It is most common in northern and central Arizona, in Yavapai, Coconino, Navajo, and Apache counties (review by ).
Kuenzler's hedgehog cactus occurs in the Guadalupe, Sacramento, and Capitan mountains of New Mexico [32,33,48]. A population has also been found in the Santa Clara Valley, Chihuahua .
Leding's hedgehog cactus is endemic to Arizona, occurring in the mountains of Pima, Graham, and Cochise counties [20,34].
Right-angled spine hedgehog cactus is distributed in Graham, Cochise, Pinal, Pima, Greenlee, and Santa Cruz counties, Arizona [20,34], southwestern New Mexico from Grant County to Hildago and Sierra counties, and in extreme southwestern Texas from El Paso County to Culbertson County. It is most common in Cochise and Santa Cruz counties, Arizona .
HABITAT TYPES AND PLANT COMMUNITIES:
Throughout its range, pinkflower hedgehog cactus occurs in desert grasslands, honey mesquite (Prosopis glandulosa) and other desert shrubland communities, pinyon-juniper (Pinus-Juniperus spp.) woodlands [12,46] dominated mostly by Colorado pinyon (P. edulis) and oneseed juniper (J. monosperma) , and pine-oak (Quercus spp.) woodlands [12,46]. At the Desert Laboratory in Arizona, pinkflower hedgehog cactus grows in a creosotebush/triangle bursage (Larrea tridentata/Ambrosia deltoidea) community . In a 1941 survey, pinkflower hedgehog cactus was rare in the Colorado River canyon, where it was usually found in association with Engelmann's hedgehog cactus (E. engelmannii) .
As of 2008, plant community descriptions of pinkflower hedgehog cactus varieties were sparse to lacking, with the exception of Kuenzler's hedgehog cactus.
In the Guadalupe, Sacramento, and Capitan mountains of New Mexico, Kuenzler's hedgehog cactus occurs in pinyon-juniper woodlands [22,32,33,40,51], mixed juniper-yucca (Yucca spp.) savannas , and desert grasslands. Blue grama (Bouteloua gracilis), sideoats grama (B. curtipendula), and curlyleaf muhly (Muhlenbergia setifolia) are commonly found in all these community types [22,32,33,40,51]. In a preliminary survey on the Lincoln National Forest, New Mexico, Kuenzler's hedgehog cactus occurred in Colorado pinyon/blue grama and oneseed juniper/blue grama woodlands . On the Bureau of Land Management's Carlsbad Unit in the Guadalupe Mountains, Kuenzler's hedgehog cactus occurred most often in oneseed juniper/blue grama communities but also occurred in yucca/curlyleaf muhly desert shrublands and curlyleaf muhly-blue grama desert grasslands. Sites dominated by green sotol (D. leiophyllum) tended to lack Kuenzler's hedgehog cacti .
Native bunchgrass cover is apparently important to Kuenzler's hedgehog cactus survival on many sites. The preliminary Lincoln National Forest survey found that mean grass cover on sites with Kuenzler's hedgehog cactus (53%) was significantly greater thatn on sites without Kuenzler's hedgehog cactus (29%) (P=0.002). Nonnative intermediate lovegrass (Eragrostis intermedia) was found most often on sites where Kuenzler's hedgehog cactus was absent . In another study on the Lincoln National Forest, mean of 24% ground cover surrounded healthy Kuenzler's hedgehog cacti, with the amount of plant biomass surrounding individual cacti positively correlated to the cactus's condition (DeBruin 1996, unpublished report cited in ). See Site Characteristics for further discussion of habitat requirements of Kuenzler's hedgehog cactus.
Right-angled hedgehog cactus occurs in pinyon-juniper woodlands in New Mexico .
GENERAL BOTANICAL CHARACTERISTICS: This description provides characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identifying pinkflower hedgehog cactus are available in these sources: [12,17,20,30].
|Kuenzler's hedgehog cactus. Photo courtesy of Robert Sivinski, New Mexico Rare Plants website.|
Descriptions of pinkflower cactus roots were unavailable as of 2008. Relatively small cacti such as pinkflower hedgehog cactus generally have shallow, widespreading, fibrous roots. Fallen stem fragments or uprooted stems tend to root rapidly .
Varieties: Pinkflower hedgehog cactus varieties are distinguished primarily by stem length; number of stems, stem ribs, central spines and/or radial spines; and spine morphology. Brief descriptions of the varieties follow. See Mellen  for detailed discussions of morphological differences among the varieties and Taylor  for a key to identifying the varieties.
Bonker's hedgehog cactus has 5.1 to 8.1-inch-long (12.7-20.3 cm) stems. Single plants usually have 5 to 15 stems with 11 to 16 ribs. Bonker's hedgehog cactus bears the shortest radial spines of the species. Spines range from 6.4 to 8 mm long and extend at right angles from the stem [34,43].
Boyce-Thompson hedgehog cactus stems range from 4.0 to 10.2 inches (10.1-25.4 cm) long, with 4 to 12 stems/plant and 12 to 18 or more ribs/plant. Spines are dense, straight, flexible, and noted for their bright, light-brown color [34,43].
Strawberry hedgehog cactus stems are 7 to 30 inches (18-76 cm) long. There are 5 to 20 stems/plant; each stem has 8 to 10 ribs. Areoles bear 12 to 13 right-angled or backward-curving spines.
Fendler's hedgehog cactus is typically <5.9 inches (15 cm) long  but may reach to 10 inches (25 cm) long and 1.5 to 3.7 inches (3.8-9.4 cm) in diameter . It usually grows as solitary plants or plants with ≤3 stems . Stems have 8 to 10 cyclindrical ribs . Each areole bears a single, curved central spine 
Kuenzler's hedgehog cactus stems range from 3.0 to 12.0 inches (7.5-30.0 cm) long [5,34]. Kuenzler's hedgehog cactus generally produces a solitary or few stems [6,33,48], with 7 to 12 ribs/stem [5,48]. Kuenzler's hedgehog cactus is distinguished by its larger flowers—which are magenta and may reach 4.3 inches (11 cm) in length [34,44,48]—, softer flower spines , and fewer spines/areole (2-7) compared with other pinkflower hedgehog cactus varieties . Chalky-white spines also characterize this variety . Kuenzler's hedgehog cactus produces 3 to 6 fruits/plant, with each fruit containing about 1,050 seeds .
Leding's hedgehog cactus stems ranging from 9.8 to 20 inches (25-51 cm) long, with 4 to 10 stems/plant. Stems are 12- to 16-ribbed. Leding's hedgehog cactus is distinguished mostly by its bright yellow spines [34,43]. Areoles bear 9 to 11 spines each, with a central spine and 0 to 3 shorter radial spines . It may occur at higher altitudes than other varieties of pinkflower hedgehog cactus .
Right-angled spine hedgehog cactus is generally smaller than other pinkflower hedgehog varieties ; stems may grow to up to 9.8 inches (25 cm) tall , with 1 to 10 stems/plant [1,20]. It has fewer ribs than other varieties  and either lacks central spines or bears a single central spine  that extends at right angles from the stem. Radial spines are straight and spreading, ranging from 6 to 8 in number and 0.2 to 0.5 inch (0.6-1.2 cm) in length .
Stand structure: Kuenzler's hedgehog cactus tends to occur on sheltered microsites [22,33]. In a survey in Lincoln, Otero, and Chaves counties, New Mexico, Kuenzler's hedgehog cacti generally grew as a solitary plants 300 feet (100 m) or more apart in juniper (Juniperus spp.)-mixed shrub savannas. Kuenzler's hedgehog cacti were mostly found growing against rocks, within grass tufts, or under a shrub canopy .
Descriptions of microsite stand structure in habitats of other pinkflower hedgehog cacti varieties were not available in the literature as of 2008.RAUNKIAER  LIFE FORM:
Pollination and breeding system: Studies on pinkflower hedgehog cactus breeding systems were lacking as of 2008. Pinkflower hedgehog cactus flowers are likely cross-pollinated by nectar-seeking insects and hummingbirds . Some report that self-pollination is unlikely for Kuenzler's hedgehog cactus (unpublished BLM data cited in , DeBruin 1996, unpublished report cited in ).
Field observations of Boyce-Thompson hedgehog cacti near Superior, Arizona, suggest that bees and possibly beetles pollinate flowers. Medium- to large-sized bees, including Apis mellifera, Megachile casadae, and M. gentilis, regularly transferred pollen to the stigmata. Pollen transfer by small bees (Ceratina nanula, Evylaeus amicus, and Perdita spp.) occurred less often. Beetles (Acmaeodera spp., Carpophilus pallipennis, Ptelon brevicornis, and Trichochrous spp.) carried pollen but were never observed on the stigma .
Seed production: As of 2008, information on pinkflower hedgehog cactus seed production was limited to Kuenzler's hedgehog cactus. On the Lincoln National Forest, Kuenzler's hedgehog cacti were 4 to 5 years old before they first flowered and produced fruit [40,51]. Surveys in Lincoln, Otero, and Chaves counties found most Kuenzler's hedgehog cacti incurred insect damage, apparently from beetles, but the damage "did not seem detrimental to fruit set" . However, larval infestations may reduce Kuenzler's hedgehog cactus seed production in some years. DeBruin (1998, as cited in ) hypothesized that Kuenzler's hedgehog cactus population size fluctuates in cycles of >10 years. Peaks in Kuenzler's hedgehog cactus populations may be followed by corresponding peaks in populations of fruit-feeding beetles. Spikes in beetle populations are may be followed by Kuenzler's hedgehog cactus population crashes (DeBruin 1998, unpublished report cited in ).
Seed dispersal: Seeds of all varieties of pinkflower hedgehog cactus are likely transported by animals, wind, and/or water. Kuenzler's hedgehog cactus seeds are apparently dispersed by frugivorous rodents, wind, and water (, unpublished BLM data cited in ). Ants have been observed harvesting Kuenzler's hedgehog cactus seeds and may aid in dispersal .
Seed banking: Kuenzler's hedgehog cactus maintains a seed bank . Seed bank studies are lacking for other varieties. Sivinski  suggests that for Kuenzler's hedgehog cactus the seed bank may be depleted by postfire germination, and replenishment of the seed bank may take 2 or more generations following wildfires that kill adult plants over a large area.
Germination: No information is available on this topic.
Growth: Growth of Kuenzler's hedgehog cactus is "erratic", with growth spurts probably dependent on favorable precipitation. In the Guadalupe Mountains, plants averaged 0.1, 0.4, and 0.6 inch (0.3, 0.9, and 1.5 cm) in diameter at 1, 2, and 3 years of age, respectively. Most 4-year-old plants exceeded 1.6 inches (4.0 cm) in diameter. Surveys conducted in 1987 and 1988 suggested a 10% annual mortality rate, with greatest losses to winter frosts (Knight and Cully 1998, unpublished reported cited in ).
Vegetative reproduction in pinkflower hedgehog cactus occurs by stem offsets [40,45,46] and fallen stem fragments . Stem offsets grow from the apical meristem of pinkflower and many other succulents, so fire or other damage to the apical meristem may hinder the ability of such succulents to produce offsets .SITE CHARACTERISTICS:
Pinkflower hedgehog cactus occupies sites from 3,000 to 7,900 feet (900-2,400 m) elevation across its range .
Pinkflower hedgehog cactus occurs in semiarid to arid climates. The mean annual precipitation reported for habitats on Tumamoc Hill, Arizona, is 9.8 inches (250 mm)/year. Nearly half of the precipitation falls from July through September .
Varieties: In New Mexico, Fendler's hedgehog cactus and right-angled spine hedgehog cactus occur on plains and slopes with sandy, gravelly, and/or rocky soils .
Kuenzler's hedgehog cactus apparently prefers warm aspects, gentle slopes, and rocky soils. In the Guadalupe Mountains, Kuenzler's hedgehog cacti grew most often on gentle, southwest-facing slopes or ridgetops [7,48] of 0% to 5% slope . A preliminary survey on the Lincoln National Forest found Kuenzler's hedgehog cactus was most common on limestone parent materials with a "fair amount" of exposed bedrock and shallow, rocky soil. Some sites had igneous parent materials. Most exposures with Kuenzler's hedgehog cactus were west- or east-facing, at elevations from 6,140 to 6,990 feet (1,870-2,130 m) . In Lincoln, Otero, and Chaves counties, New Mexico, Kuenzler's hedgehog cactus tended to favor southeast-facing slopes but grew on all aspects. It occurred on ridgetops and gentle slopes (1-3%) in soils derived mostly from limestone, with high occurrence on desert pavements of 5% to 60% cobble, rock, and/or gravel content . In a Lincoln County study, Kuenzler's hedgehog cacti were most common on east- and south-facing slopes and were rare on north-facing slopes. The majority of plants grew on the upper half of hills . Some plants were found in the open, growing out of limestone fissures with no other herbaceous vegetation within 6 feet (2 m), while other plants were growing at the bases of perennial grasses, "virtually hidden" by grass leaves .
Elevational ranges at which pinkflower hedgehog cactus infrataxa have been surveyed or collected are given below.
|Elevational ranges for pinkflower hedgehog cactus varieties|
|Variety||Elevation range (feet)|
|Bonker's hedgehog cactus||2,970-6,000 [20,43]|
|Boyce-Thompson hedgehog cactus||1,000-5,000 overall [20,34,43]; 2,000-5,000 in Arizona |
|Strawberry hedgehog cactus||100-3,740 [34,43,54]|
|Fendler's hedgehog cactus||330-7,500 in Arizona [20,43]; 6,000-8,000 in New Mexico |
|Kuenzler's hedgehog cactus||450-6,600 overall [6,32,33,43,48]; 6,000-6,990 in Otero County, New Mexico ; lowest elevations of the range are preferred |
|Leding's hedgehog cactus||330-6,000 feet in Arizona [20,34,43]|
|Right-angled spine hedgehog||5,090-7,680 [34,43] overall; 3,000-5,000 in Arizona [3,20]; 4,000-7,000 in New Mexico |
Kuenzler's hedgehog cactus is apparently moderately shade tolerant. Given their similarly (see Taxonomy), this is probably true for other pinkflower hedgehog cactus varieties. Kuenzler's hedgehog cactus has not been detected in dense pinyon-juniper woodlands. A survey in the Guadalupe Mountains found shade on sites with Kuenzler's hedgehog cactus was rarely more than 30% of total sunlight . In a preliminary survey on the Lincoln National Forest, Kuenzler's hedgehog cactus was present in very open to moderately open Colorado pinyon and oneseed juniper woodlands but not in closed-canopy woodlands. Kuenzler's hedgehog cactus density was positively correlated with forb (P=0.0000) and grass (P=0.0015) cover , suggesting that Kuenzler's hedgehog cactus shows best growth on sites with some shade and/or thermal protection (Knight and Cully 1998, published report cited in ). Mean percent grass cover on sites with Kuenzler's hedgehog cactus was 53% compared with 29% on sites without Kuenzler's hedgehog cactus. Within Kuenzler's hedgehog cactus populations, poorest plant appearance occurred on sites with lowest herbaceous cover, while plants with best appearance occurred on sites with highest herbaceous cover. Characteristics of poor appearance were damage from sun, frost, insects, and/or microbial pathogens. Litter cover (P=0.005) was significantly higher, and rock (P=0.005) and gravel (P=0.04) cover significantly lower, on sites with Kuenzler's hedgehog cactus . A survey in the Guadalupe Mountains had similar findings, with most Kuenzler's hedgehog cacti shaded by blue grama .
In the US Department of the Interior, Fish and Wildlife Service's  listing of Kuenzler's hedgehog cactus as an endangered taxon in 1979, there were no reports of Kuenzler's hedgehog cactus on sites with disturbed soils. Further information on the effects of soil disturbance on Kuenzler's hedgehog cactus was unavailable as of 2008.SEASONAL DEVELOPMENT:
|Phenology of pinkflower hedgehog cactus and its varieties|
|Pinkflower hedgehog cactus||flowers from April-June [12,34]; produces fruit from June-August |
|Boyce-Thompson hedgehog cactus||flowers in April and May in Arizona ; first flowers appeared in early April near Superior, Arizona; flowers typically lived 3-4 days |
|Strawberry hedgehog cactus||flowers in April in Arizona |
|Fendler's hedgehog cactus||flowers from May-June in Arizona ; from March-December in New Mexico ; first flowering occurred in May in the Guadalupe Mountains |
|Kuenzler's hedgehog cactus||flowers in May-early June in the Guadalupe Mountains of New Mexico [6,40,48]|
|Leding's hedgehog cactus||flowers in May in Arizona |
|Right-angled spine hedgehog||flowers in April in Arizona ; from June-July in New Mexico |
Rowe  described cacti in general as early successional fire "resisters...whose adult stages can survive low severity fires". A review  states that cacti rarely burn completely, but their spines may ignite and heat the plant's apex. Survival of pinkflower hedgehog cactus and other relatively small cacti likely depends on the amount of heat that penetrates to the apical meristem; if the apical meristem is not damaged, the cacti usually resume growth after fire. Cacti with dense spines are most susceptible to burning . Among pinkflower hedgehog cacti, varieties with relativity few spines, such as Fendler's hedgehog cactus, may be less susceptible to fire damage than varieties with many spines, such as Leding's hedgehog cactus (see General Botanical Characteristics).
Kuenzler's hedgehog cactus's habit of growing in bunchgrass clumps makes it susceptible to death when flashy fine fuels burn. Following a wildfire on the Lincoln National Forest, Kuenzler's hedgehog cactus growing within bunchgrass clumps usually died . However, low-severity fire may cause only localized tissue damage [33,40]. In 2 fire studies of Kuenzler's hedgehog cactus, a widespread wildfire caused high mortality , while a low-severity prescribed fire caused very little mortality  (see Plant response to fire).
Pinkflower hedgehog cactus seeds stored in soil probably survive all types of fire. Kuenzler's hedgehog cactus seeds in the soil seed bank survived the severe wildfire on the Lincoln National Forest .
Postfire regeneration strategy :
Ground residual colonizer (on site, initial community)
Crown residual colonizer (on site, initial community)
Secondary colonizer (on- or off-site seed sources)
Fire adaptations and plant response to fire:
Fire adaptations: As of 2008, there was very little information on adaptations of pinkflower hedgehog cactus to fire. Limited studies show pinkflower hedgehog cactus may produce from apical meristem offsets and/or establish from soil-stored seed  after fire. Gill  states that growth from the apical meristems of desert cacti is not necessarily a fire-adaptive trait, but rather an adaptation to the drought and high temperatures typical of desert habitats. However, the adaptation does help protect pinkflower hedgehog cactus from decline after fire.
Plant response to fire:
Pinkflower hedgehog cactus: Based on a single study, pinkflower hedgehog cactus recovers from fire by producing apical offsets and/or establishing from the soil seed bank . See Recovery after wildfire for further information on this study.
Except for Kuenzler's hedgehog cactus, there was no other information on postfire growth responses of pinkflower hedgehog cactus varieties as of 2008. Likewise, there was no information on how differing fire intensities or repeated fires affect pinkflower hedgehog cactus. Research is needed on all aspects of pinkflower hedgehog cactus's fire ecology .
Some postfire growth responses of cactus species in general may apply to pinkflower hedgehog cactus. Fire-damaged cacti are more resilient than many other desert plants. Singed cacti may flower and produce seed from undamaged tissue, even after uprooting . If the spines are burned off, however, pinkflower hedgehog cactus is more susceptible to herbivory than before fire [33,48]. Since cactus spines function as thermoregulators, cacti with singed spines may show delayed damage or death due to changes air flow, heat conduction and convection, and/or short-wave absorption around the plant epidermis .
Hedgehog cacti (Echinocereus) may show 1- to 3-year delayed mortality after fire (review by ), so it may take several surveys to assess total postfire mortality. Some cacti can be completely scorched with no visible green tissue, yet resume growth, while other burned cacti that initially survive a fire succumb months or years later [40,44].
In a laboratory experiment, hedgehog cactus (Echinocereus sp.) showed increasing mortality with increasing fuel loads. hedgehog cacti were burned in grass litter fuel loads ranging from 100 to 1,600 g/m², then grown in the greenhouse for 8 months. All plants burned with fuel loads of ≤400 g/m² survived the fires. Plants burned with fuel loads of 800 g/m² showed 76% mortality, and all plants burned with fuel loads of 1,600 g/m² died. Burning was done under the following conditions: fuel moisture, 20%; relative humidity, 47% to 57%; temperature, 64 to 70 ºF (19-32 ºC); wind speed <3 m/sec.
Recovery after wildfire: In a southern Arizona study, pinkflower hedgehog cactus survival was high following wildfires on 4 desert grassland sites. On burned sites, survival of pinkflower hedgehog cactus was 73%; 19 living pinkflower hedgehog cactus plants were found after fire. Fires had occurred from 0.5 to 14 months before the study, and estimated fuel loads (SE) ranged from 179 (11) to 435 (70) g/m². Approximately 74% of damaged plants recovered through apical growth, 5% by offsets, and 11% by apical growth and offsets. There were no seedlings [45,46].
Kuenzler's hedgehog cactus: Postfire establishment of Kuenzler's hedgehog cactus is from apical offsets  and soil-stored seed . As of 2008, there were 2 studies on response of Kuenzler's hedgehog cactus to fire, both conducted in the Guadalupe Mountains. Fire effects and postfire response of Kuenzler's hedgehog cactus varied with fire severity. A severe wildfire greatly reduced population size and reproductive ability , while spring prescribed fires had little effect on plant mortality, frequency of flowering, or number of flowers and fruits . Because it typically grows within bunchgrass clumps or on other sites with cover, Kuenzler's hedgehog cactus is "extremely difficult" to detect except when in flower . In the study described below, the number of Kuenzler's hedgehog cacti actually present on study sites may be greater than what was detected.
Wildfire study: A wildfire in the summer of 1992 apparently killed nearly all Kuenzler's hedgehog cactus plants in burned areas on the Lincoln National Forest. The burned site was a mosaic of mixed desert shrub-grassland and oneseed juniper-alligator juniper (J. deppeana)-bluegrama-curlyleaf muhly savanna. Elevation ranged from 5,280 to 5,410 feet (1,610-1,650 m) . The fire was severe enough to kill oneseed junipers and top-kill most desert shrub species. Since a survey was not conducted prior to the wildfire, it was impossible to precisely determine prefire densities of Kuenzler's hedgehog cactus , but Sevinski  surmised that most Kuenzler's hedgehog cacti detected after the fire established mostly from soil-stored seed in postfire year 1 or 2. Close proximity of most of the Kuenzler's hedgehog cacti on the burn to the largest concentration of unburned, adult Kuenzler's hedgehog cacti—which was near the east perimeter of the burn —raises the possibility that some seeding-in from adjacent parent plants occurred.
Mortality in burned areas was high; only 2 Kuenzler's hedgehog cactus plants seemed to have survived the fire. One of the surviving plants was found 10 feet (3 m) within the burned perimeter, where fire severity was probably low; that plant produced 3 offsets in postfire year 7. The 2nd surviving plant was in a sheltered area of barren rock. In May 1999 (postfire year 7), 110 Kuenzler's hedgehog cactus plants were found in an adjacent unburned area compared to 43 in the burned area. Many Kuenzler's hedgehog cacti that apparently established after the fire had recently reached reproductive maturity (4-5 years of age) and were in their 1st or 2nd year of flowering .
|Kuenzler's hedgehog cactus numbers in equivalent areas on Rawhide Ridge, Guadalupe Mountains, New Mexico. Data were collected in postfire year 7 .|
|Unburned area, east side||70|
|Unburned area, west side||34|
|Unburned inclusions in fire area||6|
Seedling establishment apparently stopped after the first flush of establishment in postfire years 1 and 2. The author suggests the seed bank was probably depleted after the establishment flush, and at least 2 more pulses of seedling establishment—which would require a minimum of 8 years—were needed to bring the Kuenzler's hedgehog cactus population back to prefire size .
Prescribed fire study: In a short-term study in Eddy and Lincoln counties, southeastern New Mexico, 4 low-severity prescribed fires had little impact on Kuenzler's hedgehog cactus. In a oneseed juniper-Parry's agave (Agave neomexicana)-blue grama savanna site in Eddy County, prescribed burning was conducted on 19 April and 15 June 2004. At 3 sites on the Fort Stanton Special Area of Environmental Critical Concern in Lincoln County, prescribed burning was conducted on 3 March, 12 March, and 6 April 2005 in oneseed juniper-Colorado pinyon/blue grama-sideoats grama communities. Burn sizes were small (12 m² plots), and the fire on each plot was extinguished before the next plot was ignited. Burn sites ranged from 5,200 to 6,900 feet (1,600-2,100 m) elevation, and fine fuel on the 4 sites ranged from 583 to 1,155 kg/ha. Precipitation 6 months prior to burning was above average; precipitation was near average during the 6-month period after burning. The area was surveyed for Kuenzler's hedgehog cacti before burning, with fuel loads and percent soil moisture measured sampled for each microsite with a Kuenzler's hedgehog cactus. Epidermal temperature of each cactus was monitored just prior to and after burning. During the fires, individual Kuenzler's hedgehog cacti experienced peak epidermal temperatures ranging from 78.01 to 714.99 °F (25.56-379.44 °C). Peak epidermal temperatures of Kuenzler's hedgehog cacti were related to the percent foliar cover of other plants within 11 inches (27 cm) of a cactus; soil moisture; fuel load in the entire study plot; and air temperature. Postfire surveys of the 4 burns were conducted in October 2005, and data were pooled across sites. In October 2005, there was no significant difference in Kuenzler's hedgehog cactus mortality between burned and unburned plots. Mortality of burned Kuenzler's hedgehog cacti averaged 8.31%, while mortality of unburned Kuenzler's hedgehog cacti averaged 14.32%. Fire did not affect Kuenzler's hedgehog cactus's flowering response. When comparing 111 surviving Kuenzler's hedgehog cactus on the 4 burned sites with 133 unburned control cactus in October 2005, there was no significant difference in the number of flowers or fruits on burned and unburned plants. The author concluded that the prescribed fires had no negative impact on Kuenzler's hedgehog cactus under the conditions of this study, but that more severe fires could be harmful to Kuenzler's hedgehog cactus populations .FUELS AND FIRE REGIMES:
Kuenzler's hedgehog cactus grows in the bases of bunchgrasses (blue grama, sideoats grama, and curlyleaf muhly), where fine fuels are plentiful [32,33,40], and in rocky habitats with little or no fine fuel . In the prescribed fire study in Lincoln County, New Mexico, herbaceous fuels immediately surrounding Kuenzler's hedgehog cacti ranged from 583 to 1,115 kg/ha . The author noted that this fuel load was relatively light compared to the 8,000 kg/ha that Thomas and Goodson  reported as "harmful" to Kuenzler's hedgehog cactus, but encroaching junipers and desert shrubs could increase fuel loads and risk to Kuenzler's hedgehog cactus mortality from fire .
Fire regimes: Pinkflower hedgehog cactus occurs in desert grasslands, desert shrublands, interior chaparral, pinyon-juniper, and pine-oak woodlands [12,46], which have widely ranging fire regimes. Desert grasslands may have had historic fire-return intervals that ranged from approximately 10 to 70 years , while fire-return intervals in pinyon-juniper woodlands may have historically ranged from 200 to 1,000 or more years [24,25], largely dependent on how climate and plant community composition affected fuel loads .
In pinyon-juniper woodlands, fire exclusion and livestock grazing have probably increased density of junipers over presettlement levels. Wright and Bailey  considered fire "a necessary tool" to reduce juniper in desert grasslands, shrublands, and savannas. Fires at 10- to 30-year intervals may help control woody-plant encroachment into desert grasslands and savannas [28,55,56].
Limited data on fire regimes suggest that in mixed juniper-shrub savannas of the Guadalupe Mountains, where Kuenzler's hedgehog cactus occurs, low-severity surface fires occurred about every 8 to 15 years prior to European settlement. Postsettlement livestock grazing reduced fine fuels, lengthening the mean fire-return interval. Intervals between fires continued to lengthen in the 20th century due to fire exclusion (, Cox 1999, unpublished review cited in ). Natural ignitions in the Guadalupe Mountains occur mainly in the dry season (April-June) or early in the growing season (Ahlstrand 1981, unpublished report cited in ). Historically, fire severity and size were probably variable. Within large burns, there was likely a mosaic of burned and unburned areas (Paul 2002, personal communication cited in ). As of 2003, few wildland fires had occurred in the Guadalupe Mountains since 1966 .
The Fire Regime Table summarizes characteristics of fire regimes for vegetation communities in which pinkflower hedgehog cactus may occur. 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".FIRE MANAGEMENT CONSIDERATIONS:
Prescribed fire: Because it is an endangered variety, the effects of prescribed burning on Kuenzler's hedgehog cactus have been of special concern. Fire might help increase Kuenzler's hedgehog cactus numbers by increasing germination and establishment opportunities [40,48]. Based on his survey after wildfire in the Guadalupe Mountains, Sevinski  concluded that for Kuenzler's hedgehog cactus, the "impact of fire over the long term is not so bleak". Although fire can cause high mortality in Kuenzler's hedgehog cactus, he surmised that prescribed fire need not be excluded from Kuenzler's hedgehog cactus habitats. He made these recommendations to "significantly reduce" the impact of prescribed fire on Kuenzler's hedgehog cacti :
1) Do not burn an entire Kuenzler's hedgehog cactus population in any single prescribed fire. Since local distribution of Kuenzler's hedgehog cactus is spotty and patch densities are usually very low (<5 plants), low-density patches may not have a sufficient soil seed bank to recover after fire, and rely fully or in part on seed dispersal from plants in adjacent unburned sites. Off-site colonization will likely be slow.
2) Allow sufficient time between prescribed fires to allow the burned population to recover from the first fire and establish a soil seed bank to colonize a subsequent prescribed fire. This requires several generations.
3) Survey burned areas every 10 to 15 years to assess the Kuenzler's hedgehog cactus population and refine fire prescriptions and timing as needed.A US Department of the Interior, Bureau of Land Management report concluded that "to err on the side of the species is appropriate" when using prescribed fire in Kuenzler's hedgehog cactus habitats .
Palatability/nutritional value: No information is available on this topic.
Cover value: No information is available on this topic.VALUE FOR REHABILITATION OF DISTURBED SITES:
Kuenzler's hedgehog cactus is used as an ornamental. Cultivating the cactus is legal, and Kuenzler's hedgehog cacti are commercially available , but harvesting wild plants is illegal . Harvest of wild Kuenzler's hedgehog cactus by private collectors and commercial suppliers led to a decline of the taxon in the 1970s [41,50].OTHER MANAGEMENT CONSIDERATIONS:
The Recovery Plan for downlisting Kuenzler's hedgehog cactus calls for "an increase in the numbers of the cactus to approximately 5,000 individuals and maintenance of that population for...5 consecutive years". Kuenzler's hedgehog cactus distribution and population sizes may be wider than originally thought when it was first designated a federally endangered taxon in 1979 [50,51]. At that time, <250 plants were known to exist in the wild, and the taxon was considered near extinction [11,50]. However, several field surveys conducted from 1978 and 2004 determined that at least 3,276 Kuenzler's hedgehog cactus plants existed in the wild [6,22,40,51]. Because it typically grows within bunchgrass clumps or other sites with cover, Kuenzler's hedgehog cactus is "extremely difficult" to detect except when in flower , so actual plant numbers may be 2 to 10 times greater than survey estimates (Knight and Cully 1998, unpublished report cited in . Some botanists suggest at least 6,600 Kuenzler's hedgehog cactus plants exist in the wild, but only about half of the suitable habitat has been surveyed .
Threats to Kuenzler's hedgehog cactus include private and commercial collection, habitat development, and livestock grazing, with collection the most imminent threat ([44,51], unpublished report cited in ).
Based on a preliminary survey, Chauvin and others  suggested that large reductions in herbaceous cover would be detrimental to Kuenzler's hedgehog cactus populations. See Successional Status for details.Grazing: Cattle grazing is likely detrimental to Kuenzler's hedgehog cactus [35,41,51]. Some plants are trampled by cattle , and it has not been found on sites where the soil surface is disrupted . Unpublished data from The Nature Conservancy show that during a year of cattle grazing at 65% forage utilization, Kuenzler's hedgehog cactus mortality outside an exclosure was 12.4% compared to 0% inside an exclosure . In a survey on the Bureau of Land Management's Carlsbad Unit, Kuenzler's hedgehog cactus was detected most often on moderately grazed sites, although 10 plants were found on moderately to heavily grazed sites . Chauvin and others  call for "research designed to elucidate the relationship between Kuenzler's cactus and herbaceous cover" to help assess impacts of different grazing regimes and schedules on Kuenzler's hedgehog cactus. The authors suggest that such knowledge would help managers evaluate historic grazing practices on current Kuenzler's hedgehog cactus population numbers, range, and distribution .
The following table provides fire regime information that may be relevant to pinkflower hedgehog habitats. 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".
|Fire regime information on vegetation communities in which pinkflower hedgehog cactus may occur. This information is taken from the LANDFIRE Rapid Assessment Vegetation Models , which were developed by local experts using available literature, local data, and/or expert opinion. This table summarizes fire regime characteristics for each plant community listed. The PDF file linked from each plant community name describes the model and synthesizes the knowledge available on vegetation composition, structure, and dynamics in that community. Cells are blank where information is not available in the Rapid Assessment Vegetation Model.|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Surface or low||15%||67|
|Desert grassland with shrubs and trees||Replacement||85%||12|
|Plains mesa grassland||Replacement||81%||20||3||30|
|Plains mesa grassland with shrubs or trees||Replacement||76%||20|
|Montane and subalpine grasslands||Replacement||55%||18||10||100|
|Surface or low||45%||22|
|Montane and subalpine grasslands with shrubs or trees||Replacement||30%||70||10||100|
|Surface or low||70%||30|
|Desert shrubland without grass||Replacement||52%||150|
|Interior Arizona chaparral||Replacement||100%||125||60||150|
|Pinyon-juniper (mixed fire regime)||Replacement||29%||430|
|Surface or low||6%||>1,000|
|Pinyon-juniper (rare replacement fire regime)||Replacement||76%||526|
|Surface or low||4%||>1,000|
|Ponderosa pine-Gambel oak (southern Rockies and Southwest)||Replacement||8%||300|
|Surface or low||92%||25||10||30|
|Vegetation Community (Potential Natural Vegetation Group)||Fire severity*||Fire regime characteristics|
|Percent of fires||Mean interval
|Great Basin Grassland|
|Great Basin grassland||Replacement||33%||75||40||110|
|Great Basin Shrubland|
|Creosotebush shrublands with grasses||Replacement||57%||588||300||>1,000|
|Interior Arizona chaparral||Replacement||88%||46||25||100|
|Great Basin Woodland|
|Juniper and pinyon-juniper steppe woodland||Replacement||20%||333||100||>1,000|
|Surface or low||49%||135||100|
Replacement: Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants.
Mixed: Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects.
Surface or low: Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area [16,26]
1. Anderson, Edward F. 2001. The cactus family. Portland, OR: Timber Press. 776 p. 
2. Benson, Lyman. 1982. The cacti of the United States and Canada. Stanford, CA: Stanford University Press. 1044 p. 
3. Bowers, Janice E.; McLaughlin, Steven P. 1987. Flora and vegetation of the Rincon Mountains, Pima County, Arizona. Desert Plants. 8(2): 50-94. 
4. Castetter, Edward F. 1935. Ethnobiological studies in the American Southwest. Biological Series No. 4: Volume 1. Albuquerque, NM: University of New Mexico. 62 p. 
5. Castetter, Edward F.; Pierce, Prince; Schwerin, Karl H. 1976. A new cactus species and two new varieties from New Mexico. Cactus and Succulent Journal (U.S.). 48(2): 77-78. 
6. Chauvin, Yvonne; Kennedy, Amanda; Wild, Kyleb. 2001. Survey for Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri). Albuquerque, NM: New Mexico Natural Heritage Program; University of New Mexico, Department of Biology. 29 p. + appendices. [Prepared for: Bureau of Land Management, Carlsbad Field Office]. 
7. Chauvin, Yvonne; Swineheart, Anneke; Ladyman, Juanita A. R. 1998. Kuenzler's cactus (Echinocereus fendleri var. kuenzleri) surveys. Contract No. 123--Draft: July 31, 1998; Final: October 24, 1998. Albuquerque, NM: University of New Mexico, New Mexico Natural Heritage Program. 8 p. [Report prepared for: U.S. Department of Agriculture, Forest Service, Lincoln National Forest]. 
8. Clover, Elzada U.; Jotter, Lois. 1941. Cacti of the Canyon of the Colorado River and tributaries. Bulletin of the Torrey Botanical Club. 68(6): 409-419. 
9. Dahms, Cathy W.; Geils, Brian W., tech. eds. 1997. An assessment of forest ecosystem health in the Southwest. Gen. Tech. Rep. RM-GTR-295. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 97 p. 
10. Ferguson, David J. 1989. Revision of the U.S. members of the Echinocereus triglochidiatus group. Cactus & Succulent Journal. 61: 217-224. 
11. Fletcher, Reggie A. 1985. Recovery plan for the Kuenzler's hedgehog cactus--Echinocereus fendleri Engelmann var. kuenzleri (Castetter, Pierce et Schwerin) L. Benson. Albuquerque, NM: U.S. Fish and Wildlife Service, Region 2. 44 p. [Prepared by U.S. Department of Agriculture, Forest Service, Region 3]. 
12. Flora of North America Association. 2009. Flora of North America: The flora, [Online]. Flora of North America Association (Producer). Available: http://www.fna.org/FNA. 
13. Gill, A. Malcolm. 1981. Fire adaptive traits of vascular plants. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; Lotan, J. E.; Reiners, W. A., 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: 208-230. 
14. Goldberg, Deborah E.; Turner, Raymond M. 1986. Vegetation change and plant demography in permanent plots in the Sonoran Desert. Ecology. 67(3): 695-712. 
15. Grant, Verne; Grant, Karen A. 1979. Pollination of Echinocereus fasciculatus and Ferocactus wislizenii. Plant Systematics and Evolution. 132: 85-90. 
16. Hann, Wendel; Havlina, Doug; Shlisky, Ayn; [and others]. 2008. Interagency fire regime condition class guidebook. Version 1.3, [Online]. In: Interagency fire regime condition class website. U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; The Nature Conservancy; Systems for Environmental Management (Producer). 119 p. Available: http://frames.nbii.gov/frcc/documents/FRCC_Guidebook_2008.07.10.pdf [2008, September 03]. 
17. Harrington, H. D. 1964. Manual of the plants of Colorado. 2nd ed. Chicago, IL: The Swallow Press, Inc. 666 p. 
18. Jones, Stanley D.; Wipff, Joseph K.; Montgomery, Paul M. 1997. Vascular plants of Texas. Austin, TX: University of Texas Press. 404 p. 
19. Kartesz, John T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. 1st ed. In: Kartesz, John T.; Meacham, Christopher A. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Chapel Hill, NC: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy; U.S. Department of Agriculture, Natural Resources Conservation Service; U.S. Department of the Interior, Fish and Wildlife Service. 
20. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2nd ed. Berkeley, CA: University of California Press. 1085 p. 
21. Knipe, Theodore. 1957. The javelina in Arizona: A research and management study. Wildlife Bulletin No. 2. Phoenix, AZ: State of Arizona, Game and Fish Department. 98 p. 
22. Ladyman, Juanita A. R.; Monteith, Nancy; Gegick, Patricia. 1998. Survey for Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri). Albuquerque, NM: New Mexico Natural Heritage Program; University of New Mexico. 20 p. [Report prepared for: Bureau of Land Management, Carlsbad Field Office]. 
23. LANDFIRE Rapid Assessment. 2005. Potential Natural Vegetation Group R3DGRA--Desert grasslands, [Online]. In: Rapid assessment reference condition models. In: LANDFIRE. Washington, DC: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/zip/SW/R3DGRA.pdf [2009, January 12]. 
24. LANDFIRE Rapid Assessment. 2005. Potential Natural Vegetation Group R3PIJUff--Pinyon-juniper - mixed fire regime, [Online]. In: Rapid assessment reference condition models. In: LANDFIRE. Washington, DC: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/zip/SW/R3PIJUff.pdf [2009, January 12]. 
25. LANDFIRE Rapid Assessment. 2005. Potential Natural Vegetation Group R3PIJUrf--Pinyon-juniper - rare replacement fire regime, [Online]. In: Rapid assessment reference condition models. In: LANDFIRE. Washington, DC: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/zip/SW/R3PIJUrf.pdf [2009, January 12]. 
26. LANDFIRE Rapid Assessment. 2005. Reference condition modeling manual (Version 2.1), [Online]. In: LANDFIRE. Cooperative Agreement 04-CA-11132543-189. Boulder, CO: The Nature Conservancy; U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior (Producers). 72 p. Available: http://www.landfire.gov/downloadfile.php?file=RA_Modeling_Manual_v2_1.pdf [2007, May 24]. 
27. LANDFIRE Rapid Assessment. 2007. Rapid assessment reference condition models, [Online]. In: LANDFIRE. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/models_EW.php [2008, April 18] 
28. Leopold, Aldo. 1924. Grass, brush, timber, and fire in southern Arizona. Journal of Forestry. 22(6): 1-10. 
29. Lewis, Donald A.; Nobel, Park S. 1997. Thermal energy exchange model and water loss of a barrel cactus, Ferocactus acanthodes. Plant Physiology. 60: 609-612. 
30. Martin, William C.; Hutchins, Charles R. 1981. A flora of New Mexico. Volume 2. Germany: J. Cramer. 2589 p. 
31. May, Ben; Wester, David B.; Britton, Carlton M. 2003. Effects of prescribed burning on a threatened cactus in New Mexico. In: Ballard, Warren B.; Wallace, Mark C., eds. Research highlights--2003: Range, wildlife and fisheries management. Volume 34. Lubbock, TX: Texas Tech University, College of Agricultural Sciences and Natural Resources: 15. 
32. May, Ben; Wester, David B.; Britton, Carlton M. 2004. Microhabitat characteristics of Kuenzler's cactus. In: Wallace, Mark C.; Britton, Carlton, eds. Research Highlights - 2004: Range, wildlife, and fisheries management. Volume 35. Lubbock, TX: Texas Tech University: 28. 
33. May, Benjamin C. 2006. The effects of fire on Kuenzler's hedgehog cactus. Lubbock, TX: Texas Tech University. 81 p. Thesis. 
34. Mellen, Georganne. 1991. The Echinocereus fendleri controversy. Cactus and Succulent Journal (U.S.). 63(4): 208-212. 
35. Merola-Zwartjes, Michele. 2004. Biodiversity, functional processes, and the ecological consequences of fragmentation in southwestern grasslands. In: Finch, Deborah M., ed. Assessment of grassland ecosystem conditions in the southwestern United States. Gen. Tech. Rep. RMRS-GTR-135-vol. 1. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 49-85. 
36. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
37. Rowe, J. S. 1983. Concepts of fire effects on plant individuals and species. In: Wein, Ross W.; MacLean, David A., eds. The role of fire in northern circumpolar ecosystems. SCOPE 18. New York: John Wiley & Sons: 135-154. 
38. Rydberg, Per Axel. 1906. Flora of Colorado. Bulletin 100. Fort Collins, CO: Colorado Agricultural College, Agricultural Experiment Station. 448 p. 
39. Shreve, Forrest; Hinckley, Arthur L. 1937. Thirty years of change in desert vegetation. Ecology. 18(4): 463-478. 
40. Sivinski, Robert C. 2007. Effects of a natural fire on a Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri) and nylon hedgehog cactus (Echinocereus viridiflorus) population in southeastern New Mexico. In: Barlow-Irick, P.; Anderson, J.; McDonald, C., tech. eds. Southwestern rare and endangered plants: Proceedings, 4th conference; 2004, March 22-26; Las Cruces, NM. RMRS-P-48CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 93-97. 
41. Spellenberg, Richard. 1993. Species of special concern. In: Dick-Peddie, William A., ed. New Mexico vegetation: Past, present, and future. Albuquerque, NM: University of New Mexico Press: 179-224. 
42. Stickney, Peter F. 1989. Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. FEIS workshop: Postfire regeneration. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 10 p. 
43. Taylor, Nigel P. 1985. The genus Echinocereus. Kew Magazine Monograph. Middlesex, England: Collingridge Books. 160 p. In association with The Royal Botanical Gardens, Kew. 
44. Thomas, P. A. 1991. Response of succulents to fire: a review. International Journal of Wildland Fire. 1(1): 11-22. 
45. Thomas, P. A. 1997. Fire and the conservation of succulents in grasslands. In: Greenlee, Jason M., ed. Proceedings, 1st conference on fire effects on rare and endangered species and habitats; 1995 November 13-16; Coeur d'Alene, ID. Fairfield, WA: International Association of Wildland Fire: 173-178. 
46. Thomas, P. A.; Goodson, P. 1992. Conservation of succulents in desert grasslands managed by fire. Biological Conservation. 60(2): 91-100. 
47. U.S. Department of Agriculture, Natural Resources Conservation Service. 2009. PLANTS Database, [Online]. Available: http://plants.usda.gov/. 
48. U.S. Department of the Interior, Bureau of Land Management. 2003. Biological evaluation: Effects of fire on Kuenzler's hedgehog cactus (Echinocereus fendleri var. Kuenzleri), an endangered species in the northern Chihuahuan Desert. Carlsbad, NM: U.S. Department of the Interior, Bureau of Land Management. 19 p. 
49. U.S. Department of the Interior, Fish and Wildlife Service. 2016. Endangered Species Program, [Online]. Available: http://www.fws.gov/endangered/. 
50. U.S. Department of the Interior, Fish and Wildlife Service. 1979. Federal Register 50 CFR: Rules and regulations. Final rule: Determination that Echinocereus kuenzleri is an endangered species. Federal Register: 1979, October 26. 44(209): 61924-61927. 
51. U.S. Department of the Interior, Fish and Wildlife Service. 2005. Five-year review determination: Kuenzler's hedgehog cactus. Albuquerque, NM: U.S. Fish and Wildlife Service, Region 2; Ecological Services Field Office. 18 p. 
52. Weber, William A. 1987. Colorado flora: western slope. Boulder, CO: Colorado Associated University Press. 530 p. 
53. Weniger, Del. 1970. Cacti of the Southwest: Texas, New Mexico, Oklahoma, Arkansas, and Louisiana. The Elma Dill Russell Spencer Foundation Series No. 4. Austin, TX: University of Texas Press. 247 p. 
54. Wiens, John F. 2000. Vegetation and flora of Ragged Top, Pima County, Arizona. Desert Plants. 16(2): 3-31. 
55. Wilkinson, Margot Carolina. 1997. Reconstruction of historical fire regimes along an elevation and vegetation gradient in the Sacramento Mountains, New Mexico. Tucson, AZ: The University of Arizona. 128 p. Thesis. 
56. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p.