Spea hammondii - (Baird, 1859)
Western Spadefoot
Other English Common Names: western spadefoot
Synonym(s): Scaphiopus hammondii Baird, 1859 "1857" ;Spea (=Scaphiopus) hammondii Baird, 1859 "1857"
Taxonomic Status: Accepted
Related ITIS Name(s): Spea hammondii (Baird, 1859) (TSN 206990)
Unique Identifier: ELEMENT_GLOBAL.2.100387
Element Code: AAABF02020
Informal Taxonomy: Animals, Vertebrates - Amphibians - Frogs and Toads
Kingdom Phylum Class Order Family Genus
Animalia Craniata Amphibia Anura Scaphiopodidae Spea
Genus Size: B - Very small genus (2-5 species)
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Concept Reference
Concept Reference: Wiens, J. J., and T. A. Titus. 1991. A phylogenetic analysis of Spea (Anura: Pelobatidae). Herpetologica 47:21-28.
Concept Reference Code: A91WIE01NAUS
Name Used in Concept Reference: Spea hammondii
Taxonomic Comments: Placed in the genus Scaphiopus by some authors. Hall (1998) argued against the recognition of Spea as a distinct genus, but most authors have accepted the split of Spea from Scaphiopus.

Wiens and Titus (1991) presented a phylogenetic analysis of the genus (or subgenus) Spea based on allozymic and morphological data. Regarded as conspecific with S. multiplicatus until 1976 (Brown 1976); some authors retain multiplicatus within hammondi (Tanner 1989), but various data support the contention that these are distinct species (see Wiens and Titus 1991).

Garcia-Paris et al. (2003) used mtDNA to examine the phylogentic relationships of Pelobatoidea and found that the family Pelobatidae, as previously defined, is not monophyletic (Pelobates is sister to Megophryidae, not to Spea/Scaphiopus). They split the Pelobatidae into two families: Eurasian spadefoot toads (Pelobates), which retain the name Pelobatidae, and North American spadefoot toads (Scaphiopus, Spea), which make up the revived family Scaphiopodidae.
Conservation Status

NatureServe Status

Global Status: G3
Global Status Last Reviewed: 27Apr2005
Global Status Last Changed: 03Dec2001
Rounded Global Status: G3 - Vulnerable
Reasons: Nearly endemic to central and southwestern California, also occurs in northwestern Baja California; extirpated from many sites in the Central Valley and coastal southern California; declining due to impacts of urbanization and agricultural development; some populations may be threatened by habitat fragmentation or exotic species (mosquitofish stocked for mosquito abatement, bullfrogs).
Nation: United States
National Status: N3 (03Dec2001)

U.S. & Canada State/Province Status
United States California (S3)

Other Statuses

IUCN Red List Category: NT - Near threatened

NatureServe Global Conservation Status Factors

Range Extent: 250-20,000 square km (about 100-8000 square miles)
Range Extent Comments: The range includes the Central Valley and bordering foothills of California and the Coast Ranges (south of San Francisco Bay) and extends southward into northwestern Baja California, Mexico. The species has been extirpated throughout much of lowland southern California. Elevational range extends from near sea level to elevations of up to about 1,363 m (Zeiner et al. 1988, cited by Jennings and Hayes 1994; Ervin et al. 2001), but usually below 910 m (Stebbins 1985).

Number of Occurrences: 21 - 80
Number of Occurrences Comments: Jennings and Hayes (1994) mapped several dozen localities with extant populations.

Population Size: 10,000 - 1,000,000 individuals
Population Size Comments: Total adult population size is unknown; likely at least many thousands.

Overall Threat Impact Comments: Main threat is development and conversion of habitat to incompatible uses (urbanization, agricultural development) (Davidson et al. 2002). Recruitment may be unsuccessful in pools with introduced fishes (e.g., mosquitofish used for mosquito abatement).

Short-term Trend: Decline of 10-30%
Short-term Trend Comments: Since the 1950s, drastic declines have been noted in the Central Valley and southern Califoria. In southern California, more than 80% of the previously occupied habitat has been developed or converted to incompatible uses; more than 30% in northern and central California (Jennings and Hayes 1994).

Long-term Trend:  
Long-term Trend Comments: Unknown level of decline in extent of occurrence, population size, area of occurrence, and number/condition of occurrences.

Other NatureServe Conservation Status Information

Protection Needs: Protect assemblages of rainpool habitat throughout the range.

Global Range: (250-20,000 square km (about 100-8000 square miles)) The range includes the Central Valley and bordering foothills of California and the Coast Ranges (south of San Francisco Bay) and extends southward into northwestern Baja California, Mexico. The species has been extirpated throughout much of lowland southern California. Elevational range extends from near sea level to elevations of up to about 1,363 m (Zeiner et al. 1988, cited by Jennings and Hayes 1994; Ervin et al. 2001), but usually below 910 m (Stebbins 1985).

U.S. States and Canadian Provinces
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

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

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: IUCN, Conservation International, NatureServe, and collaborators, 2004

U.S. Distribution by County Help
State County Name (FIPS Code)
CA Alameda (06001), Butte (06007), Calaveras (06009), Colusa (06011), Fresno (06019), Glenn (06021), Kern (06029), Kings (06031), Los Angeles (06037), Madera (06039), Mariposa (06043), Merced (06047), Monterey (06053), Orange (06059), Placer (06061), Riverside (06065), Sacramento (06067), San Benito (06069), San Diego (06073), San Joaquin (06077), San Luis Obispo (06079), Santa Barbara (06083), Siskiyou (06093), Stanislaus (06099), Tehama (06103), Tulare (06107), Ventura (06111), Yolo (06113)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
18 Lower Pit (18020003)+, Sacramento-Stone Corral (18020104)+, Lower American (18020111)+, Upper Stony (18020115)+, Cottonwood Creek (18020152)+, Paynes Creek-Sacramento River (18020155)+, Thomes Creek-Sacramento River (18020156)+, Big Chico Creek-Sacramento River (18020157)+, Honcut Headwaters-Lower Feather (18020159)+*, Upper Coon-Upper Auburn (18020161)+, Lower Sacramento (18020163)+, Middle Kern-Upper Tehachapi- (18030003)+, Upper Deer-Upper White (18030005)+, Upper Kaweah (18030007)+, Upper Dry (18030009)+, Tulare-Buena Vista Lakes (18030012)+, Middle San Joaquin-Lower (18040001)+, Middle San Joaquin-Lower (18040002)+, San Joaquin Delta (18040003)+, Upper San Joaquin (18040006)+*, Upper Chowchilla-Upper Fresno (18040007)+, Upper Merced (18040008)+, Upper Tuolumne (18040009)+, Upper Stanislaus (18040010)+, Upper Calaveras (18040011)+, Upper Mokelumne (18040012)+, Upper Cosumnes (18040013)+, Rock Creek-French Camp Slough (18040051)+, San Francisco Bay (18050004)+, Pajaro (18060002)+, Carrizo Plain (18060003)+, Estrella (18060004)+, Salinas (18060005)+, Central Coastal (18060006)+, Cuyama (18060007)+, Santa Maria (18060008)+, San Antonio (18060009)+, Santa Ynez (18060010)+, Santa Clara (18070102)+, Calleguas (18070103)+, Los Angeles (18070105)+, San Gabriel (18070106)+, San Jacinto (18070202)+, Santa Ana (18070203)+, Newport Bay (18070204)+, Aliso-San Onofre (18070301)+, Santa Margarita (18070302)+, San Luis Rey-Escondido (18070303)+, San Diego (18070304)+, Cottonwood-Tijuana (18070305)+, Whitewater River (18100201)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: A spadefoot toad.
Reproduction Comments: Breeds January-May. Female lays cylindrical mass of eggs.
Ecology Comments: May dig its own burrow or use those of other animals. Skin secretion smells like peanuts and maybe an irritant to handlers.
Non-Migrant: N
Locally Migrant: Y
Long Distance Migrant: N
Mobility and Migration Comments: Migrates up to at least several hundred meters between nonbreeding and breeding habitats.
Riverine Habitat(s): CREEK, Pool
Palustrine Habitat(s): TEMPORARY POOL
Terrestrial Habitat(s): Cropland/hedgerow, Grassland/herbaceous, Playa/salt flat, Savanna, Shrubland/chaparral, Woodland - Hardwood, Woodland - Mixed
Special Habitat Factors: Benthic, Burrowing in or using soil
Habitat Comments: This species lives in a wide range of habitats; lowlands to foothills, grasslands, open chaparral, pine-oak woodlands. It prefers shortgrass plains, sandy or gravelly soil (e.g., alkali flats, washes, alluvial fans). It is fossorial and breeds in temporary rain pools and slow-moving streams (e.g., areas flooded by intermittent streams).
Adult Food Habits: Invertivore
Immature Food Habits: Carnivore, Herbivore, Invertivore, Scavenger
Food Comments: Adults invertivorous; larvae eat algae, organic debris, plant tissue, etc., sometimes small animals (e.g., crustaceans, tadpoles).
Adult Phenology: Hibernates/aestivates, Nocturnal
Immature Phenology: Hibernates/aestivates, Nocturnal
Phenology Comments: Inactive underground throughout much of the year. Most active during rains of winter-spring breeding period. Remains below ground during dry/cold weather.
Colonial Breeder: Y
Length: 6 centimeters
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation
Group Name: Spadefoots

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals (including larvae or eggs) in or near appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Busy major highway, especially at night, such that toads rarely if ever cross successfully; urban development dominated by buildings and pavement; the largest, widest, fast-flowing rivers.
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Spadefoots can cross some fairly wide flowing rivers, so only the biggest rivers with strong current should be treated as barriers.

Detailed information on movements of these toads is not available, but opportunistic field observations of various species indicate that they readily move up to at least several hundred meters from breeding sites (G. Hammerson, pers. obs.). The separation distance for unsuitable habitat reflects the nominal minimum value of 1 km. The separation distance for suitable habitat reflects the good vagility of spadefoots, their ability to utilize ephemeral or newly created breeding sites, and the consequent likely low probability that two occupied locations separated by less than several kilometers of suitable habitat would represent truly independent populations over the long term.

Adults tend to exhibit high fidelity to breeding sites. For example, in Florida, inter-pond exchange of adults was minimal and short-distance (130 m; one was 416 m) (Greenberg and Tanner 2005), but recaptures were rare and some dispersals may have been missed. Additionally metamorphs may disperse large distances and probably sometimes eventually breed in distant non-natal pools. In Florida, Greenberg and Tanner (2005) did not track inter-pond movement by Scaphiopus holbrookii metamorphs, but it appeared likely that metamorphs ''rescue'' local populations by breeding-4 or 5 years later-in non-natal ponds as adults.

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .5 km
Inferred Minimum Extent Justification: Inferred extent distance refers to distance from breeding sites and is likely a conservative value.
Date: 15Apr2005
Author: Hammerson, G.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 27Apr2005
NatureServe Conservation Status Factors Author: Clausen, M. K., and G. Hammerson
Element Ecology & Life History Edition Date: 31Dec2002
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).

  • Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.

  • Blackburn, L., P. Nanjappa, and M. J. Lannoo. 2001. An Atlas of the Distribution of U.S. Amphibians. Copyright, Ball State University, Muncie, Indiana, USA.

  • Bragg, A.N. 1965. Gnomes of the night. the spadefoot toads. 127 pp.

  • Brown, H. A. 1976. The status of California and Arizona populations of the western spadefoot toads (genus Scaphio- pus). Los Angeles Co. Mus. Nat. Hist. Contr. Sci. 286:1-15.

  • Davidson, C., H. B. Shaffer, and M. R. Jennings. 2002. Spatial tests of the pesticide drift, habitat destruction, UV-B, and climate-change hypotheses for California amphibian declines. Conservation Biology 16:1588-1601.

  • Ervin, E. L., A. E. Anderson, T. L. Cass, and R. E. Murcia. 2001. Spea hammondii. Elevation record. Herpetological Review 32:36.

  • Frost, D. R. 1985. Amphibian species of the world. A taxonomic and geographical reference. Allen Press, Inc., and The Association of Systematics Collections, Lawrence, Kansas. v + 732 pp.

  • García-París, M., D.R. Buchholtz, and G. Parra-Olea. 2003. Phylogenetic relationships of Pelobatoidea re-examined using mtDNA. Molecular Phylogenetics and Evolution 28:12-23.

  • Hall, J.A. 1998. Scaphiopus intermontanus. Catalogue of American Amphibians and Reptiles. 650:1-17.

  • Jennings, M. R., and M. P. Hayes. 1994. Amphibian and reptile species of special concern in California. Final Report submitted to the California Department of Fish and Game, Inland Fisheries Division. Contract No. 8023. 255 pp.

  • Morey, S. and Reznick, D. 2004. The relationship between habitat permanence and larval development in California spadefoot toads: field and laboratory comparisons of developmental plasticity. Oikos. 104:172-190.

  • Stebbins, R. C. 1954a. Amphibians and reptiles of western North America. McGraw-Hill Book Company, New York.

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

  • Tanner, W. W. 1989. Status of SPEA STAGNALIS Cope (1875), SPEA INTERMONTANUS Cope (1889), and a systematic review of SPEA HAMMONDII Baird (1839) (Amphibia: Anura). Great Basin Nat. 49:503-510.

  • Wiens, J. J., and T. A. Titus. 1991. A phylogenetic analysis of Spea (Anura: Pelobatidae). Herpetologica 47:21-28.

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