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Echinocereus fendleri


Table of Contents


INTRODUCTORY


Figure 1—Pinkflower hedgehog cactus. Photo courtesy of Wayne Scott Ray.

AUTHORSHIP AND CITATION:
Hauser, A. Scott; Fryer, Janet L. 2008. [Revised 2018]. Echinocereus fendleri, pinkflower hedgehog cactus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/cactus/echfen/all.html [].

Revisions:
On 4 December 2018, new information was added to the Fire Effects and Management section, and the Taxonomy section was updated. New images were also added.

FEIS ABBREVIATION:
ECHFEN
ECHFENF
ECHFENR

NRCS PLANT CODE [60]:
ECFE
ECFEF3
ECFER4

COMMON NAMES:
pinkflower hedgehog cactus
Fendler's hedgehog cactus
right-angled spine hedgehog cactus
Kuenzler's hedgehog cactus

TAXONOMY:
The scientific name of pinkflower hedgehog cactus is Echinocereus fendleri (Engelm.) Sencke ex J.N. Haage (Cactaceae) [15,22]. Systematists disagree on the number of valid subspecies within Echinocereus fendleri [1,2,38]. Mellen [38] discusses the controversies surrounding systematic classification of pinkflower hedgehog cactus infrataxa. Two subspecies are widely recognized:

Echinocereus fendleri (Engelm.) Sencke ex J.N. Haage subsp. fenderi [1,22,60], Fendler's hedgehog cactus
Echinocereus fendleri (Engelm.) Sencke ex J.N. Haage subsp. rectispinus (Peebles) N.P. Taylor [22,60], right-angled spine hedgehog cactus

Some systematists recognize a third entity, Kuenzler's hedgehog cactus, which is listed as a Federally Endangered Species [56]. However, there is disagreement over the taxonomic treatment of Kuenzler's hedgehog cactus [1]. While some authorities consider it a synonym of Echinocereus fendleri subsp. fendleri [60], others suggest Kuenzler's hedgehog cactus is best treated as a distinct taxon, either Echinocereus fendleri subsp. kuenzleri [1] or Echinocereus fendleri var. kuenzleri [59,60]. In recognition of its Federal Legal Status, Kuenzler's hedgehog cactus is treated as a distinct subspecies in this Species Review; however, FEIS recognizes that further resolution is needed on the taxonomic classification of Kuenzler's hedgehog cactus.

In this Species Review, "pinkflower hedgehog cactus" refers to the species as a whole, and subspecies are referred to by the common names listed above.

Hybridization occurs among Echinocereus taxa. Scarlet hedgehog cactus (E. coccineus) × pinkflower hedgehog cactus and kingcup cactus (E. triglochidiatus) × pinkflower hedgehog cactus hybrids are likely sterile [13]. Subspecies of pinkflower hedgehog cactus also hybridize and are fertile. A Kuenzler's hedgehog cactus × Fendler's hedgehog cactus hybrid occur at the northwestern edge of Kuenzler's hedgehog cactus's range ([59], Knight 2002, personal communication cited in [57]).

SYNONYMS:
for Echinocereus fendleri (Engelm.) Sencke ex J.N. Haage:
Echinocereus fendleri (Engelm.) Engelm. ex Rumpler [2,23,44,51,61]
Cereus fendleri Engelmann [15,44]

for Echinocereus fendleri subsp. fenderi:
Echinocereus fendleri var. fendleri (Engelm.) F. Seitz [1,2,15,21,22,23,33,62]
Echinocereus fendleri subsp. hempelii F. Fobe (documented in [60])

for: Echinocereus fendleri (Engelm.) Sencke ex J.N. Haage subsp. rectispinus (Peebles) N.P. Taylor:
Echinocereus fendleri var. rectispinus (Peebles) L. Benson [1,2,3,15,21,22,23,33,51,62]
Echinocereus hempelii F. Fobe subsp. rectispinus (Peebles) N.P. Taylor
Echinocereus rectispinus Peebles (documented in [60])

for Echinocereus fendleri subsp. kuenzleri Castetter, Pierce & Schwerin:
Echinocereus fendleri var. kuenzleri (Castetter, Pierce & Schwerin) L. Benson [2,15,22,51]
Echinocereus kuenzleri Castetter [7]

LIFE FORM:
Cactus

FEDERAL LEGAL STATUS:
Kuenzler's hedgehog cactus is Endangered [56].

OTHER STATUS:
NatureServe ranks Kuenzler's hedgehog cactus as T2Q: Questionable taxonomy. Taxonomic distinctiveness of this entity at the current level is questionable; resolution of this uncertainty may result in inclusion of this taxon in another taxon, with the resulting taxon having a lower-priority conservation status [40].

DISTRIBUTION AND OCCURRENCE

SPECIES: Echinocereus fendleri

GENERAL DISTRIBUTION:
Pinkflower hedgehog cactus is native to Arizona, Colorado, New Mexico, Texas, and Chihuahua and Sonora, Mexico. It is most common in New Mexico, and occupies only small areas of southwestern Colorado, and western Texas ([15], review by [38]).

Figure 2—Overall distribution of pinkflower hedgehog cactus.

 
Figure 3—Distributions of Fendler's hedgehog cactus (right) and right-angled spine hedgehog cactus (left). Maps courtesy of USDA, NRCS. 2018. The PLANTS Database. National Plant Data Team, Greensboro, NC. (2018, October 5). Lightly shaded areas indicate no information is provided at the county level [60].

Fendler's hedgehog cactus occurs in Arizona and New Mexico. It is reported in southwestern Texas near the upper Pecos River, and in northern Chihuahua, Mexico. It is most common in northern and central Arizona, in Yavapai, Coconino, Navajo, and Apache counties (review by [33]).

Right-angled spine hedgehog cactus occurs in Graham, Cochise, Pinal, Pima, Greenlee, and Santa Cruz counties, Arizona [23,38] and in southwestern New Mexico from Grant County to Hildago and Sierra counties. It is reported in extreme southwestern Texas from El Paso County to Culbertson County. It is most common in Cochise and Santa Cruz counties, Arizona [38].

Kuenzler's hedgehog cactus occurs in the Guadalupe, Sacramento, and Capitan mountains of New Mexico [35,36,57]. A population also occurs in the Santa Clara Valley, Chihuahua [38].

STATES:
United States: AZ, NM, TX
Mexico

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 [15,55] dominated mostly by Colorado pinyon (P. edulis) and oneseed juniper (J. monosperma) [9], and pine-oak (Quercus spp.) woodlands [15,55]. At the Desert Laboratory in Arizona, pinkflower hedgehog cactus grows in a creosotebush/triangle bursage (Larrea tridentata/Ambrosia deltoidea) community [45]. 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) [10].

Right-angled hedgehog cactus occurs in pinyon-juniper woodlands in New Mexico [33].

As of 2008, plant community descriptions of pinkflower hedgehog cactus infrataxa 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 [25,35,36,47,59], mixed juniper-yucca (Yucca spp.) savannas [25], and desert grasslands. Blue grama (Bouteloua gracilis), sideoats grama (B. curtipendula), and curlyleaf muhly (Muhlenbergia setifolia) are commonly found in all these community types [25,35,36,47,59]. 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 [9]. 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 [8].

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 than 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 [9]. 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 [36]). See Site Characteristics for further discussion of habitat requirements of Kuenzler's hedgehog cactus.

BOTANICAL AND ECOLOGICAL CHARACTERISTICS

SPECIES: Echinocereus fendleri
 


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: [15,20,23,33].
 
Figure 4—Fendler's hedgehog cactus in Sedona, AZ. Photo courtesy of Wikimedia Commons, https://commons.wikimedia.org/w/index.php?curid=19905473.
Species description: Pinkflower hedgehog cactus is a small perennial succulent [47]. It grows as single-stemmed individuals or in small, loose clone clusters of 10 or more stems [1,20,38,61]. Stems are erect to slightly decumbent [1,15,38] and are generally 3 to 6.7 inches (7.5-17 cm) tall and 1.5 to 3 inches (3.8-7.5 cm) wide [15], reaching a maximum height of 10 inches (30 cm) and width of 4 inches (10 cm) [1,15,20]. Each stem has 8 to 18 ribs. There are 3 to 5 central spines, varying from 0.4- to 2.4-inch (6.2-10 cm) long. There are 2 to 12 straight or curved 0.4- to 0.8-inch-long (1-2 cm) radial spines/areola [15,38]. Flowers are borne on the upper part of the plant [20]. They are 2 to 4.3 inches × 2 to 4.3 inches (5-11 cm) across, with a long flower tube (0.4 to 0.59 (1-1.5 cm) × 0.4 to 1.0 inches (1-3 cm)) [15]. Fruits are ovoid or globose, spiny [20], and 0.8 to 2 inches (2-5 cm) long [15]. The name "hedgehog cactus" derives from the fanciful resemblance of the fruit to the round, spiny body of a hedgehog [38]. Seeds are 1 to 2 mm long [20,38]. Pinkflower hedgehog cactus is described as long-lived [47]. At Tumamoc Hill, Arizona, the longest an individual pinkflower hedgehog cactus was observed to live was 9 years [17].

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 [2].

Subspecies: Pinkflower hedgehog cactus subspecies are distinguished primarily by stem length; number of stems, stem ribs, central spines and/or radial spines; and spine morphology. Brief descriptions of the subspecies follow. See Mellen [38] for detailed discussions of morphological differences among the subspecies and Taylor [51] for a key to identifying the subspecies.

Fendler's hedgehog cactus is typically <5.9 inches (15 cm) long [23] but may reach to 10 inches (25 cm) long and 1.5 to 3.7 inches (3.8-9.4 cm) in diameter [38]. It usually grows as solitary plants or plants with ≤3 stems [1]. Stems have 8 to 10 cyclindrical ribs [38]. Each areole bears a single, curved central spine [1]

Right-angled spine hedgehog cactus is generally smaller than other pinkflower hedgehog subspecies [51]; stems may grow to up to 9.8 inches (25 cm) tall [33], with 1 to 10 stems/plant [1,23]. It has fewer ribs than other subspecies [51] and either lacks central spines or bears a single central spine [1] 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 [38].

Kuenzler's hedgehog cactus stems range from 3.0 to 12.0 inches (7.5-30.0 cm) long [7,38]. Kuenzler's hedgehog cactus generally produces a solitary or few stems [8,36,57], with 7 to 12 ribs/stem [7,57]. Kuenzler's hedgehog cactus is distinguished by its larger flowers—which are magenta and may reach 4.3 inches (11 cm) in length [38,52,57]—, softer flower spines [7], and fewer spines/areole (2-7) compared with other pinkflower hedgehog cactus subspecies [38]. Chalky-white spines also characterize this variety [52]. Kuenzler's hedgehog cactus produces 3 to 6 fruits/plant, with each fruit containing about 1,050 seeds [14].

Stand structure: Kuenzler's hedgehog cactus tends to occur on sheltered microsites [25,36]. 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 [25].

Descriptions of microsite stand structure in habitats of other pinkflower hedgehog cacti subspecies were not available in the literature as of 2008.

RAUNKIAER [41] LIFE FORM:
Stem succulent

REGENERATION PROCESSES:
Pinkflower hedgehog cactus reproduces sexually and vegetatively [47,53,55,59].

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 [13]. Some report that self-pollination is unlikely for Kuenzler's hedgehog cactus (unpublished BLM data cited in [59], DeBruin 1996, unpublished report cited in [36]).

Field observations of a closely related species, Boyce-Thompson hedgehog cactus (Echinocereus boyce-thompsonii) near Superior, Arizona, suggest that bees and possibly beetles pollinate flowers of Echinocereus species. Medium- to large-sized bees, including Apis mellifera, Megachile casadae, and M. gentilis, regularly transferred pollen to the stigmata of Boyce-Thompson hedgehog cactus. 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 [18].

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 [47,59]. 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" [25]. However, larval infestations may reduce Kuenzler's hedgehog cactus seed production in some years. DeBruin (1998, as cited in [36]) 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 [36]).

Seed dispersal: Seeds of all subspecies 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 ([57], unpublished BLM data cited in [59]). Ants have been observed harvesting Kuenzler's hedgehog cactus seeds and may aid in dispersal [58].

Seed banking: Kuenzler's hedgehog cactus maintains a seed bank [47]. Seed bank studies are lacking for other subspecies. Sivinski [47] 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 was available on this topic as of 2008.

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 [36]).

Vegetative reproduction in pinkflower hedgehog cactus occurs by stem offshoots [47,53,55] and fallen stem fragments [2]. Stem offshoots 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 offshoots [36].

SITE CHARACTERISTICS:
Species: Throughout its range pinkflower hedgehog cactus occurs on dry plains and hills, rocky, open, south-facing slopes, and in canyon bottoms [15,20,20,34,44,61]. It occupies sandy, rocky, or gravelly soils derived from limestone or igneous parent materials [3,15,33,36,38]. At the Desert Laboratory in Arizona, pinkflower hedgehog cactus habitats occur on deep rhyolitic outwashes and loam soils [45].

Pinkflower hedgehog cactus occupies sites from 3,000 to 7,900 feet (900-2,400 m) elevation across its range [15].

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 [17].

Subspecies: 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 [33].

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 [9,57] of 0% to 5% slope [57]. 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) [9]. 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 [25]. 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 [36]. 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 [35].

Elevational ranges at which pinkflower hedgehog cactus infrataxa have been surveyed or collected are given below.

Table 1—Elevational ranges for pinkflower hedgehog cactus subspecies.
Variety Elevation range (feet)
Fendler's hedgehog cactus 330-7,500 in Arizona [23,51]; 6,000-8,000 in New Mexico [33]
Right-angled spine hedgehog 5,090-7,680 [38,51] overall; 3,000-5,000 in Arizona [3,23]; 4,000-7,000 in New Mexico [33]
Kuenzler's hedgehog cactus 450-6,600 overall [8,35,36,51,57]; 6,000-6,990 in Otero County, New Mexico [7]; lowest elevations of the range are preferred [52]

SUCCESSIONAL STATUS:
Information regarding the successional status of pinkflower hedgehog cactus is generally lacking. More information is needed on the successional patterns of all pinkflower hedgehog cactus subspecies.

Kuenzler's hedgehog cactus is apparently moderately shade tolerant. Given their similarly (see Taxonomy), this is probably true for other pinkflower hedgehog cactus infrataxa. 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 [8]. 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 [9], 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 [36]). 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 [9]. A survey in the Guadalupe Mountains had similar findings, with most Kuenzler's hedgehog cacti shaded by blue grama [8].

SEASONAL DEVELOPMENT:
Pinkflower hedgehog cactus generally begins flowering in midspring. In 1999the warmest spring of the last century in the Guadalupe Mountains Kuenzler's hedgehog cactus first flowered on 11 May. Latest flowering date recorded for Kuenzler's hedgehog cactus was 7 June (Knight 2000, personal communication cited in [57]). Ranges of the flowering period of pinkflower hedgehog cactus are given below.

Table 2—Phenology of pinkflower hedgehog cactus and its subspecies.
Taxon Event
Pinkflower hedgehog cactus flowers from April-June [15,38]; produces fruit from June-August [15]
Fendler's hedgehog cactus flowers from May-June in Arizona [23]; from March-December in New Mexico [33]; first flowering occurred in May in the Guadalupe Mountains [47]
Right-angled spine hedgehog flowers in April in Arizona [23]; from June-July in New Mexico [33]
Kuenzler's hedgehog cactus flowers in May-early June in the Guadalupe Mountains of New Mexico [8,47,57]

FIRE EFFECTS AND MANAGEMENT

SPECIES: Echinocereus fendleri
FIRE EFFECTS: Immediate fire effect on plant: Low-severity fire likely has little long-term impact on pinkflower hedgehog cactus plants, whereas severe fire probably kills pinkflower hedgehog plants. However, documentation of the effects of fire on most pinkflower hedgehog cactus subspecies was lacking as of 2008.

Rowe [43] described cacti in general as early successional fire "resisters...whose adult stages can survive low severity fires". In general, succulent cacti such as pinkflower hedgehog cactus rarely burn. Stems scorch and blister without pyrolysis, which may leave undamaged parts of the plant alive. However, when cacti with dense spines—such as pinkflower hedgehog cactus (see fig. 4)—are singed, the spines may ignite and singe growing-tip tissues (apical meristems). If the apical meristem is undamaged, the cactus may survive fire and resume growth. Apex survival is critical for small cacti because postfire growth from other meristems (above or below ground) is rare [36,52]. Survival of pinkflower hedgehog cactus and other small cacti 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. Single-stemmed individuals are probably killed due to their small size and lack of insulation from surrounding stems. When pinkflower hedgehog cactus forms clusters, interior stems may be protected by outer stems and survive fire. Pinkflower hedgehog cactus growing in rocky refugia or other areas with sparse fuels likely escape most fires. Densely spined plants are most susceptible to burning [52]. Among pinkflower hedgehog cacti, subspecies with relativity few spines, such as Fendler's hedgehog cactus, may be less susceptible to fire damage than subspecies with many spines.

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 [47]. However, low-severity fire may cause only localized tissue damage [36,47]. In 2 fire studies of Kuenzler's hedgehog cactus, a widespread wildfire caused high mortality [47], while a low-severity prescribed fire caused very little mortality [36] (see Plant response to fire).

Pinkflower hedgehog cactus and other hedgehog cacti (Echinocereus) may show 1- to 3-year delayed mortality after fire (review by [52]), 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 [47,52]. Secondary postfire morality of Echinocereus species can result when fire burns off the spines. Postfire freezing may occur because spines affect airflow, heat conduction and convection, and short-wave light absorbance in cacti [32]. Removal of the spines by fire may increase subsequent herbivory from browsing mammals [11,49] and insects [5], resulting in slow recovery time or plant death [52]. In New Mexico, a survey at postfire year 7 showed only 2 of 20 Fendler's hedgehog cacti were still alive after a wildfire in a twoneedle pinyon-Utah juniper/Pinchot's juniper (Pinus edulis-Juniperus osteosperma-J.pinchotii) woodland [46].

Pinkflower hedgehog cactus seeds stored in soil probably survive all but ground fires. Kuenzler's hedgehog cactus apparently established from soil-stored seeds after a 1992 stand-replacing wildfire on the Lincoln National Forest [47].

Postfire regeneration strategy [50]:
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 2018, there was very little information on adaptations of pinkflower hedgehog cactus to fire. Limited studies show pinkflower hedgehog cactus may produce from apical meristem offshoots and/or establish from soil-stored seed [47] after fire. Gill [16] 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. Fallen stem fragments [2] of small cacti may sprout after fire.

Plant response to fire:
Information of response of pinkflower hedgehog cactus to fire was sparse as of 2018. A study in the Guadalupe Mountains found it produced apical offshoots and established from the soil seed bank after a wildfire [47]. See Recovery after wildfire for further information on this study.

Light fuel loads likely improve chances of pinkflower cactus survival. Simulated grassland fires in potted cacti found mortality of pinkflower hedgehog cactus and bundle hedgehog cactus (E. fasciculatus) varied with fuel load and fuel depth (i.e., amount of grass litter). Potted cacti were burned at 5 fuel loads ranging from 100 to 1,600 g/m² with three replicates for each species. No fire mortality occurred with a fuel load of <800 g/m², but two of three plants of each species died with a fuel load of 800 g/m². All three hedgehog cactus plants of each species died with a fuel load of 1,600 g/m² [55].

Except for Kuenzler's hedgehog cactus (see Recovery after wildfire), there was no information on postfire growth responses of pinkflower hedgehog cactus infrataxa as of 2018. 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 [53].

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 [52]. If the spines are burned off, however, pinkflower hedgehog cactus is more susceptible to herbivory than before fire [36,57]. 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 [32]. Responses of other cacti in the Echinocereus genus may give insight to postfire response of pinkflower hedgehog cactus.

Limited studies show a pattern of high mortality of Echinocereus species from fire [4,42,46,55]. In the Mojave Desert near Palm Springs, California, scattered Engelmann's hedgehog cactus (E. engelmannii) individuals sprouted after a wildfire, but sprouting individuals were "surrounded by numerous skeletons of dead" Engelmann's hedgehog cacti [4]. Surveys of multiple burns in southern Arizona found mortality of Engelmann's hedgehog cactus averaged 82% on burned sites and 46% on adjacent unburned sites [55]. One year after an October wildfire in a Texas shortgrass prairie, mortality of nylon hedgehog cactus (E. viridiflorus) was higher on burned than on unburned plots (91% vs. 19%, respectively), and surviving plants on burned plots were shorter and smaller in diameter (P < 0.001) [42].

Limited information suggests delayed mortality in burned Echinocereus plants. In the Sonoran Desert of Arizona, very few bundle hedgehog cactus survived a wildfire in a burrobush-blue paloverde (Ambrosia dumosa-Parkinsonia florida) grassland. Mean density of bundle hedgehog cactus was 14 plants/acre (35/ha) in postfire year 1 and 8 plants/acre (20/ha) in postfire year 2. Mean density in an adjacent unburned site was much higher, at 84 plants/acre (205/ha) (P < 0.05). Overall mortality of burned bundle hedgehog cactus averaged 88% in postfire year 2. Three percent of the burned plants were only top-killed and sprouted by postfire year 2. Nine percent of the plants escaped the fire [37]. In mixed-grass little bluestem-buffalograss (Schizachyrium scoparium-Bouteloua dactyloides) prairie in Callahan County, Texas, spring prescribed fire "severely damaged" lace hedgehog cactus (E. reichenbachii). Mortality averaged 17% in postfire year 1 and 94% by postfire year 3. Most surviving plants were in areas with low prefire fuel loads (<890 lb/acre (1,000 kg/ha)) [5]. This study did not use control plots, so comparison with mortality on unburned sites is impossible. However in an Arizona desert grassland, Thomas [54] found mortality of rainbow cactus (E. pectinatus) increased from the time of an initial postfire survey and a survey in postfire year 1 (P < 0.001). By postfire year 2, mean mortality was 10.2 times greater on burned plots compared to unburned plots [54].

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 offshoots, and 11% by apical growth and offshoots. There were no seedlings [53,55].

Kuenzler's hedgehog cactus: Postfire establishment of Kuenzler's hedgehog cactus is from apical offshoots [47] and soil-stored seed [47]. As of 2018, 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 [47], while spring prescribed fires had little effect on plant mortality, frequency of flowering, or number of flowers and fruits [36]. 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 [47]. 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)-blue grama-curlyleaf muhly savanna. Elevation ranged from 5,280 to 5,410 feet (1,610-1,650 m) [47]. 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 [36], but Sevinski [47] 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 [47]—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 offshoots 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 [47].

Table 3—Kuenzler's hedgehog cactus numbers in equivalent areas on Rawhide Ridge, Guadalupe Mountains, New Mexico. Data were collected in postfire year 7 [47].
Burned area 43
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 [47].

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 [36].

FUELS AND FIRE REGIMES: Fuels: Except for Kuenzler's hedgehog cactus, there was almost no research to date (2008) on fuel loads on microsites where pinkflower hedgehog cacti grow. On some sites, pinkflower hedgehog cactus grows in rocky areas with little fuel and low probability of fire [55].

Kuenzler's hedgehog cactus grows in the bases of bunchgrasses (blue grama, sideoats grama, and curlyleaf muhly), where fine fuels are plentiful [35,36,47], and in rocky habitats with little or no fine fuel [35]. 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 [36]. The author noted that this fuel load was relatively light compared to the 8,000 kg/ha that Thomas and Goodson [55] 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 [36].

Fire regimes: Pinkflower hedgehog cactus occurs in desert grasslands, desert shrublands, interior chaparral, pinyon-juniper, and pine-oak woodlands [15,55], which have widely ranging fire regimes. Desert grasslands may have had historic fire-return intervals that ranged from approximately 10 to 70 years [26], while fire-return intervals in pinyon-juniper woodlands may have historically ranged from 200 to 1,000 or more years [27,28], largely dependent on how climate and plant community composition affected fuel loads [65].

In pinyon-juniper woodlands, fire exclusion and livestock grazing have probably increased density of junipers over presettlement levels. Wright and Bailey [65] 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 [31,64,65].

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 ([12], Cox 1999, unpublished review cited in [57]). 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 [57]). 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 [57]). As of 2003, few wildland fires had occurred in the Guadalupe Mountains since 1966 [57].

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 "Echinocereus fendleri" in the FEIS home page under "Find Fire Regimes".

FIRE MANAGEMENT CONSIDERATIONS:
Except for Kuenzler's hedgehog cactus, there is no research upon which to base management recommendations for subspecies of pinkflower hedgehog cactus. Preliminary guidelines for using prescribed fire in plant communities with Kuenzler's hedgehog cactus would probably also apply to other subspecies of pinkflower hedgehog cactus.

Prescribed fire: Because of its federal protection status, 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 [47,57]. Based on his survey after wildfire in the Guadalupe Mountains, Sevinski [47] 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 [47]:

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 USDA, 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 [57].

MANAGEMENT CONSIDERATIONS

SPECIES: Echinocereus fendleri
IMPORTANCE TO WILDLIFE AND LIVESTOCK:
There is very little information on the importance of pinkflower hedgehog cactus to wildlife and livestock. In a study during the 1940s and 1950s in the Santa Catalina, Black, Tortolita, Tucson, and Santa Rita mountains of Arizona, hedgehog cacti (Echinocereus spp.) were a relatively important food source for collared peccary [24]. Grazing animals eat the fruits ([57], unpublished USDA, BLM data cited in [59]) and stems, especially if the spines are burned off or otherwise removed [36,57].

Palatability/nutritional value: No information was available on this topic.

Cover value: No information was available on this topic.

VALUE FOR REHABILITATION OF DISTURBED SITES:
No information was available on this topic.

OTHER USES:
The fruit of pinkflower hedgehog cactus is edible [20]. The Cochiti ate the stems [6], and the Hopi ate the fruits fresh and dried [1].

Kuenzler's hedgehog cactus is used as an ornamental. Cultivating the cactus is legal, and Kuenzler's hedgehog cacti are commercially available [58], but harvesting wild plants is illegal [56]. Harvest of wild Kuenzler's hedgehog cactus by private collectors and commercial suppliers contributed to a decline of the taxon by the 1970s [48,58].

OTHER MANAGEMENT CONSIDERATIONS:
Except for Kuenzler's hedgehog cactus, information on managing subspecies of pinkflower hedgehog cactus was lacking as of 2008.

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 [58,59]. At that time, <250 plants were known to exist in the wild, and the taxon was considered near extinction [14,58]. However, several field surveys conducted from 1978 and 2004 determined that at least 3,276 Kuenzler's hedgehog cactus plants existed in the wild [8,25,47,59]. 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 [47], so actual plant numbers may be 2 to 10 times greater than survey estimates (Knight and Cully 1998, unpublished report cited in [36]. 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 [59].

Threats to Kuenzler's hedgehog cactus include private and commercial collection, habitat development, and livestock grazing, with collection the most imminent threat ([52,59], unpublished report cited in [57]).

Based on a preliminary survey, Chauvin and others [9] 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 [39,48,59]. Some plants are trampled by cattle [52], and it has not been found on sites where the soil surface is disrupted [58]. 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 [59]. 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 [8]. Chauvin and others [9] 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 [9].

APPENDIX: FIRE REGIME TABLE

SPECIES: Echinocereus fendleri

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 "Echinocereus fendleri" 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 [29], 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.
Southwest Great Basin
Southwest
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Southwest Grassland
Desert grassland Replacement 85% 12    
Surface or low 15% 67    
Desert grassland with shrubs and trees Replacement 85% 12    
Mixed 15% 70    
Plains mesa grassland Replacement 81% 20 3 30
Mixed 19% 85 3 150
Plains mesa grassland with shrubs or trees Replacement 76% 20    
Mixed 24% 65    
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    
Southwest Shrubland
Desert shrubland without grass Replacement 52% 150    
Mixed 48% 165    
Interior Arizona chaparral Replacement 100% 125 60 150
Southwest Woodland
Mesquite bosques Replacement 32% 135    
Mixed 67% 65    
Pinyon-juniper (mixed fire regime) Replacement 29% 430    
Mixed 65% 192    
Surface or low 6% >1,000    
Pinyon-juniper (rare replacement fire regime) Replacement 76% 526    
Mixed 20% >1,000    
Surface or low 4% >1,000    
Southwest Forested
Ponderosa pine-Gambel oak (southern Rockies and Southwest) Replacement 8% 300    
Surface or low 92% 25 10 30
Great Basin
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
(years)
Minimum interval
(years)
Maximum interval
(years)
Great Basin Grassland
Great Basin grassland Replacement 33% 75 40 110
Mixed 67% 37 20 54
Great Basin Shrubland
Creosotebush shrublands with grasses Replacement 57% 588 300 >1,000
Mixed 43% 769 300 >1,000
Interior Arizona chaparral Replacement 88% 46 25 100
Mixed 12% 350    
Great Basin Woodland
Juniper and pinyon-juniper steppe woodland Replacement 20% 333 100 >1,000
Mixed 31% 217 100 >1,000
Surface or low 49% 135 100  
*Fire Severities—
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 [19].

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