Charina umbratica - Klauber, 1943
Southern Rubber Boa
Synonym(s): Charina bottae umbratica Klauber, 1943
Taxonomic Status: Accepted
Related ITIS Name(s): Charina umbratica Klauber, 1943 (TSN 683027)
Unique Identifier: ELEMENT_GLOBAL.2.101155
Element Code: ARADA01011
Informal Taxonomy: Animals, Vertebrates - Reptiles - Snakes
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Reptilia Squamata Boidae Charina
Genus Size: B - Very small genus (2-5 species)
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Concept Reference
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Concept Reference: U.S. Fish and Wildlife Service (USFWS). 1994. Endangered and Threatened Wildlife and Plants; Animal Candidate Review for Listing as Endangered or Threatened Species. Federal Register 59(219):58982-59028.
Concept Reference Code: N94FWS02EHUS
Name Used in Concept Reference: Charina bottae umbratica
Taxonomic Comments: Nussbaum and Hoyer (1974) showed that subspecies utahensis is indistiguishable from subspecies bottae, and they regarded the concept "umbratica" as meaningless. In contrast, Erwin (1974) proposed that subspecies umbratica warrants species status; at that time, this suggestion did not gain the support of other herpetologists. Stewart (1977) recognized two subspecies (bottae and umbratica) and, pending further study, regarded populations from Mt. Pinos and the Tehachapi Mountains, California, as intergrades between these two subspecies. Stebbins (1985) continued to recognize three subspecies (bottae, utahensis, and umbratica). Rodriguez-Robles et al. (2001) used mtDNA data to examine phylogeography of C. bottae and concluded that "C. b. umbratica is a genetically cohesive, allopatric taxon that is morphologically diagnosable" [using a suite of traits] and that "it is an independent evolutionary unit that should be recognized as a distinct species, Charina umbratica." The authors acknowledged that a mixture of bottae and umbratica traits exists in populations in the Tehachapi Mountains and Mount Pinos, but they interpreted this as persistent ancestral polymorphisms. They also found no support for recognizing utahensis as a valid taxon. Crother (2008) listed C. umbratica as a species whereas Stebbins (2003) mentioned the proposal but did not adopt the split.
Conservation Status
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NatureServe Status

Global Status: G2G3
Global Status Last Reviewed: 04Apr2016
Global Status Last Changed: 16Jun2009
Ranking Methodology Used: Ranked by calculator
Rounded Global Status: G2 - Imperiled
Reasons: Small range in mountains of southern California; known from several dozen localities; population size unknown but locally common; trend uncertain but probably declining; habitat loss and degradation associated with human population expansion (private land development) and fire and fuels management are the primary problems.
Nation: United States
National Status: N2N3 (16Jun2009)

U.S. & Canada State/Province Status
United States California (S2S3)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent: 1000-5000 square km (about 400-2000 square miles)
Range Extent Comments: Range encompasses the San Bernardino Mountains and San Jacinto Mountains of southern California and perhaps additional areas to the north. Charina populations in the southern Sierra Nevada, Tehachapi Mountains, and on Mt. Pinos, Mt. Abel, Mt. Alamo, and Frazier Mountain are of uncertain taxonomic status; they have some umbratica characterisitcs but based on mtDNA data were included in the C. bottae (northern rubber boa) clade by Rodriguez-Robles et al. (2001), whereas Stebbins and McGinnis (2012) assigned these populations to C. umbratica. Elevational range is 1,540-2,460 meters (Stewart 1988). Twenty-six of the 40+ localities in the San Bernardino Mountains are in a 16-kilometer strip between Twin Peaks on the west and Green Valley on the east (Stewart 1988).

Extent of occurrence for the populations in the San Bernardino Mountains and San Jacinto Mountains appears to be between 2,000 and 3,000 square kilometers, based on one minimum convex polygon. Overall population does not appear to be severely fragmented.

Area of Occupancy: 26-500 4-km2 grid cells
Area of Occupancy Comments: Area of occupancy is unknown but presumably is at least a few hundred square kilometers.

Number of Occurrences: 1 - 5
Number of Occurrences Comments: The number of distinct occurrences has not been determined using standardized criteria, but it could be as few as two or perhaps several, depending on the selected criteria. The species is represented by at least several distinct locations (as defined by IUCN). The species is known from at least 48 localities (8 in the San Jacinto Mountains and more than 40 in the San Bernardino Mountains) (Stewart 1988, 1991). No doubt this secretive species will be found in many additional less readily accessible sites when those areas are adequately searched.

Population Size: 2500 - 10,000 individuals
Population Size Comments: Population size is unknown but is presumed to include at least a few thousand adults. This species is secretive, sometimes hard to find (particularly when weather is cold in winter or hot and dry in summer), and may appear to be rare, but it can be locally common in favorable habitat.

Number of Occurrences with Good Viability/Integrity: Unknown

Overall Threat Impact: Medium
Overall Threat Impact Comments: Primary threats are habitat loss and degradation resulting from resort/residential development, logging, and wood gathering; habitat degradation resulting from the effects of airborne pollutants on upland ecosystems is a potential threat (California Dept. of Fish & Game 1990). Private lands that may support rubber boa populations are being developed or otherwise modified at a rapid pace. The area between Crestline and the Snow Valley Ski Area long has been considered the best rubber boa habitat in the San Bernardino Mountains; in the early 1990s, 44 percent of this area was private land subject to development (Stewart 1991); most of the recorded rubber boa localities were in this area, and most of these were on private property (Los Padres Forestwatch).

Off-highway-vehicle (OHV) use (causing direct mortality and degrading habitat) may be a threat in some areas. Unauthorized fuelwood gathering and OHV use have been better regulated on forest service lands in recent years (Los Padres Forestwatch).

Illegal collection for the pet trade could be a problem in some readily accessible recreation areas.

Recent drought and associated tree mortality and ground disturbance associated with ongoing fuels reduction efforts may have negative affects on rubber boa populations, but the effects and degree of these potential threats are unknown.

Short-term Trend: Decline of <30% to relatively stable
Short-term Trend Comments: Trend over the past 10 years or three generations is uncertain, but distribution and abundance probably have continued to decline (estimated at less than 30 percent).

Long-term Trend: Decline of 10-30%
Long-term Trend Comments: Over the long term (200 years), distribution and abundance undoubtedly have declined, but the magnitude of the decline is uncertain.

Other NatureServe Conservation Status Information

Inventory Needs: Better information on current distribution and abundance is needed, particularly in locations with good habitat away from easily accessible areas.

Protection Needs: Protection of habitat on forest service lands will increase in importance as most rubber boa habitat on private lands is developed over the next few decades.

Distribution
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Global Range: (1000-5000 square km (about 400-2000 square miles)) Range encompasses the San Bernardino Mountains and San Jacinto Mountains of southern California and perhaps additional areas to the north. Charina populations in the southern Sierra Nevada, Tehachapi Mountains, and on Mt. Pinos, Mt. Abel, Mt. Alamo, and Frazier Mountain are of uncertain taxonomic status; they have some umbratica characterisitcs but based on mtDNA data were included in the C. bottae (northern rubber boa) clade by Rodriguez-Robles et al. (2001), whereas Stebbins and McGinnis (2012) assigned these populations to C. umbratica. Elevational range is 1,540-2,460 meters (Stewart 1988). Twenty-six of the 40+ localities in the San Bernardino Mountains are in a 16-kilometer strip between Twin Peaks on the west and Green Valley on the east (Stewart 1988).

Extent of occurrence for the populations in the San Bernardino Mountains and San Jacinto Mountains appears to be between 2,000 and 3,000 square kilometers, based on one minimum convex polygon. Overall population does not appear to be severely fragmented.

U.S. States and Canadian Provinces
Color legend for Distribution Map
Endemism: endemic to a single state or province

U.S. & Canada State/Province Distribution
United States CA

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
CA Kern (06029)*, Riverside (06065), San Bernardino (06071), Ventura (06111)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
18 Middle Kern-Upper Tehachapi- (18030003)+*, Cuyama (18060007)+*, Santa Clara (18070102)+*, San Jacinto (18070202)+, Santa Ana (18070203)+, Mojave (18090208)+, Whitewater River (18100201)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A stout-bodied, rubbery-looking snake.
Reproduction Comments: This live-bearing snake copulates in spring and gives birth to usually 2-5 (sometimes up to 8-9) young in late summer (August-September) (Hoyer and Stewart 2000). Maximum life span extends to several decades (R. Hoyer)..
Habitat Type: Terrestrial
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: N
Mobility and Migration Comments: Movements have not been studied using adequate methodology, but individuals are commonly found close to previous capture sites (Hoyer and Stewart 2000). In some areas, individuals make small migrations between winter hibernaula on ridges and summer habitat in canyon bottoms. Loe (1985) recorded movement of up to 274 meters within a single season.
Palustrine Habitat(s): Riparian
Terrestrial Habitat(s): Bare rock/talus/scree, Forest - Conifer, Forest - Hardwood, Forest - Mixed, Forest Edge, Forest/Woodland, Savanna, Woodland - Mixed
Special Habitat Factors: Burrowing in or using soil, Fallen log/debris
Habitat Comments: Habitat includes coniferous and deciduous semi-open forests and woodlands (Jeffrey pine, yellow pine, sugar pine, white fir, black oak), forest clearings, patchy chaparral/shrubland, meadows, and grassy savannas, commonly in riparian zones or around rock outcrops (Stebbins 2003). In summer, this snake is most readily found in damp draws and near seeps and springs where conditions are relatively moist (Loe 1985). Generally it is found in or under rotting logs or stumps, under rocks or in crevices, or under the bark of dead fallen trees; these serve as important cover and help maintain suitably moist conditions. In the San Bernardino Mountains, apparent hibernacula were in rock outcrops (Hoyer and Stewart 2000).
Adult Food Habits: Carnivore
Immature Food Habits: Carnivore
Food Comments: Diet includes mice, shrews, lizards, lizard eggs, snakes, and small birds (Hoyer and Stewart 2000, Stebbins 2003). This snake generally kills its prey by constriction prior to ingestion.
Adult Phenology: Crepuscular, Diurnal, Hibernates/aestivates, Nocturnal
Immature Phenology: Crepuscular, Diurnal, Hibernates/aestivates, Nocturnal
Phenology Comments: Activity occurs mostly at night or dusk but also commonly occurs in daytime during mild cloudy weather. Most activity occurs from late March through October (Loe 1985), with some activity beyond this range during suitable weather.
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Appropriate management consists primarily of protection and maintenance of suitable habitat conditions, particularly along riparian corridors and around rocky outcrops. Coarse woody debris on the ground is an important habitat component. In addition to appropriate management of forest service lands, protection of known and potential habitat on private lands would be beneficial.
Population/Occurrence Delineation Not yet assessed
Help
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 04Apr2016
NatureServe Conservation Status Factors Author: Hammerson, G.
Element Ecology & Life History Edition Date: 04Apr2016
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.

  • Collins, J. T., and T. W. Taggart. 2009. Standard common and current scientific names for North American amphibians, turtles, reptiles, and crocodilians. Sixth edition. The Center for North American Herpetology, Lawrance, Kansas. iv + 44 pp.

  • Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84. Online with updates at: http://www.ssarherps.org/pages/comm_names/Index.php

  • Crother, B. I. (editor). 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 7th edition. SSAR Herpetological Circular 39:1-92.

  • Erwin, D. B. 1974. Taxonomic status of the southern rubber boa, Charina bottae umbratica. Copeia 1974:996-997.

  • Feldman, C. R., and G. S. Spicer. 2006. Comparative phylogeography of woodland reptiles in California: repeated patterns of cladogenesis and population expansion. Molecular Ecology 15:2201-2222.

  • Hoyer, R. F., and G. R. Stewart. 2000a. Biology of the rubber boa (Charina bottae), with emphasis on C. b. umbratica. Part I: capture, size, sexual dimorphism, and reproduction. Journal of Herpetology 34:348-354.

  • Hoyer, R. F., and G. R. Stewart. 2000b. Biology of the rubber boa (Charina bottae), with emphasis on C. b. umbratica. Part II: diet, antagonists, and predators. Journal of Herpetology 34:354-360.

  • Loe, S. 1985. Habitat management guide for southern rubber boa (Charina bottae umbratica) on the San Bernardino National Forest. Prepared for the U.S. Department of Agriculture San Bernardino National Forest.

  • Nussbaum, R. A., and R. F. Hoyer. 1974. Geographic variation and the validity of subspecies in the rubber boa, Charina bottae (Blainville). Northwest Sci. 48:219-229.

  • Rodriguez-Robles, J. A., G. R. Stewart, and T. J. Pappenfuss. 2001. Mitochondrial DNA-based phylogeography of North American rubber boas, Charina bottae (Serpentes: Boidae). Molecular Phylogenetics and Evolution 18:227-237.

  • Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.

  • Stebbins, R. C., and S. M. McGinnis. 2012. Field guide to amphibians and reptiles of California. Revised edition. University of California Press, Berkeley.

  • Stewart, G. R. 1988. The rubber boa (Charina bottae) in California, with particular reference to the subspecies, C. b. umbratica. In: Proceedings of the conference on California herpetology. Van Nuys, CA: Southwestern Herpetologists' Society Special Publication No. 4.

  • Stewart, G. R. 1991. Status of the southern rubber boa (Charina bottae umbratica) in the San Bernardino Mountains of southern California. Report Submitted to U.S. Fish and Wildlife Service, Laguna Niguel Field Office. Contract number 10120-87-00342. October 1, 1990. Revised March 1, 1991.

  • Stewart, G.R. 1977. Charina, C. bottae. Cat. Am. Amph. Rep. 205.1-205.2.

  • U.S. Fish and Wildlife Service (USFWS). 1994. Endangered and Threatened Wildlife and Plants; Animal Candidate Review for Listing as Endangered or Threatened Species. Federal Register 59(219):58982-59028.

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