Ambystoma barbouri

Geographic Range

Ambystoma barbouri (streamside salamanders) are native throughout central Kentucky, with their range extending up into some parts of southwestern Ohio and sparingly in southeastern Indiana (Kraus and Petranka, 1989). A small population was recorded in the northwestern corner of West Virginia (Green, 1955). Most recently, populations were discovered in the Central Basin of middle Tennessee (Scott et al. 1997).

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Streamside salamanders occupy upland deciduous forest in areas of varying latitude (Kraus and Petranka, 1989). Outside of breeding season, they prefer to inhabit burrows near first- and second-order headwaters with a high abundance of limestone and exposed bedrock (Petranka, 1998). Adults utilize these shallow, ephemeral streams (and sometimes, adjacent pools) for breeding and depositing eggs. Larvae live in the streams until metamorphosis, after which adapting a largely fossorial lifestyle (Petranka, 1998).

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• forest forest

• Aquatic Biomes
• rivers and streams
• temporary pools

Physical Description

Ambystoma barbouri largely resembles its sibling species, A. texanum : a mottled gray and tan ambystomatid with a small head and mouth (Kraus and Petranka, 1989). The two were not separated into their own species until Kraus and Petranka defined them as a new species in 1989. They are average size ambystomatid salamanders (up to 150mm total length) with approximately 15 costal grooves along their sides (Anderson 1967). They can be differentiated from A. texanum most easily by range and habitat-use, but also vary in certain dentition and have a broad dorsal maxillary process (Kraus and Petranka, 1989).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

Development

The eggs deposited by streamside salamanders are larger in size and of smaller overall clutch size than that of A. texanum . It makes sense, then, that their larvae are both slightly larger and of a more advanced developmental stage than small-mouthed salamanders when hatching (Kraus and Petranka, 1989). However, unlike their sibling species, A. barbouri larvae have a somewhat short window as larvae, usually metamorphosing within 60 days of hatching (Petranka et al. 1987). Because of this, streamside larvae metamorphose into juveniles of much smaller size than metamorphic small-mouthed salamanders (Petranka and Sih, 1987).

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Unlike a lot of Ambystoma salamanders, breeding occurs independently of rain events (i.e. not “explosive” breeders), and has been recorded starting in December and lasting as late as early April.

• Mating System
• polygynous polygynous
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Breeding season begins with migratory movement of adult salamanders to stream breeding sites from late October into early March. The beginning of migration is strongly correlated with rainfall. Males usually migrate toward the breeding sites before females.

Ambystoma barbouri eggs are internally fertilized via spermatophores deposited by males on the submerged underside of flat, streambed rocks (Kraus and Petranka, 1989). Males begin courtship by dramatically undulating their tail while swimming around the shallow stream underneath cover rocks. They do this while occasionally nudging the female, and then deposit spermatophores to the submerged rock (Petranka, 1982b). Females pick up the spermatophores from the submerged rock surface, and it is under these refugia that other courtship behaviors are thought to occur (Kraus and Petranka 1989). After fertilization, females deposit their eggs onto the submerged rock surface in monolayers (Petranka, 1982a).

Communal nesting by females is thought to be passive, due to the low number of available flat rocks for oviposition in most stream breeding sites studied (Petranka, 1984).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous

Little is known about the parental investment of Ambystoma barbouri .

Lifespan/Longevity

The exact lifespan of streamside salamanders is unknown.

Behavior

Adults are fossorial and non-breeding season behavior is relatively unstudied, as is in most ambystomatid species. It is known that adult streamside salamanders burrow in sites near the streams, and migrate toward stream sites when breeding season begins in autumn.

• Key Behaviors
• fossorial fossorial
• motile motile
• migratory migratory

Communication and Perception

Ambystoma salamanders are thought to communicate primarily via chemosensation and tactile cues (in the form of courtship nudging) during the breeding season.

• Communication Channels
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

One study analyzing the gut contents of larvae showed macrozooplankton and chironimid larvae in high abundance, as well as amphipod and isopods as high-volume prey (Smith and Petranka, 1987). Larvae have also been shown to consume large numbers of isopods in a separate study (Huang and Sih, 1991).

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • vermivore

• Animal Foods
• insects
• terrestrial non-insect arthropods
• terrestrial worms
• zooplankton zooplankton

Predation

Due to their semi-aquatic life cycle, the streamside salamander is prey to a mix of different predators. During their stream-dwelling larval stage, they are especially vulnerable to fish (Petranka, 1983). Flatworms have been shown to be in high abundance with stream larvae, and are also a known predator of both the larvae and eggs (Petranka et al. 1987). There have also been reports of northern water snake and crayfish predation on larvae (Kats, 1986; Petranka, 1998).

Larvae use refugia to hide from visual detection of sunfish in an effective anti-predator strategy (Huang and Sih 1990). Adult streamside salamander anti-predator behavior has not been well-studied, but its sibling species, A. texanum , exhibit either an immobility response or by coiling its tail over its head when faced with a predator (Brodie, Johnson, and Dodd, 1974; Brodie, 1977).

Ecosystem Roles

Streamside salamanders are an important part of the complex lateral connectivity of streams and the nearby terrestrial environment. Their larvae are important prey to sunfish, flatworms, northern waterfish, and crayfish (Petranka, 1983; Petranka et al. 1987; Kats, 1986; Petranka, 1998). Additionally, larvae manage isopod populations and are important predators of various stream macroinvertebrates (Smith and Petranka, 1987).

Economic Importance for Humans: Positive

A. barbouri may serve as an important trophic linkage maintaining insect and other invertebrate populations that without, humans would have to increase dependence on environmentally-harmful pesticides.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

There has been no evidence to suggest streamside salamanders have a negative effect on humans.

Conservation Status

Listed as “near threatened” by the IUCN Redlist due to a small area of occurrence as well as shrinking habitat size and degraded habitat quality (Hammerson, 2004). Studies have pointed toward habitat degradation, construction of roads, and overall urbanization near streamside habitat as reason for decline (Petranka 1998, Watson and Pauley 2005, Niemiller et al. 2006). During the breeding season, adults crossing roads while migrating to streams may be hit by oncoming traffic, demonstrating how road construction may increase adult mortality (Niemiller et al. 2009).

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Katy Gardner (author), Missouri State University, Brian Greene (editor), Missouri State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Anderson, J. 1967. Ambystoma texanum . Catalogue of American Amphibians and Reptiles : 1-2.

Brodie, E., J. Johnson, C. Dodd. 1974. Immobility as a defensive behavior in salamanders. Herpetologica , 30: 79-85.

Brodie, E. 1977. Salamander antipredator postures. Copeia , 1977: 523-535.

Green, N. 1956. The ambystomatid salamanders of West Virginia. Proceedings of the West Virginia Academy of Science , 27: 16-18.

Hammerson, G. 2004. " Ambystoma barbouri " (On-line). The IUCN Red List of Threatened Species. Accessed May 20, 2017 at http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T59053A11875949.en .

Huang, C., A. Sih. 1991. An experimental study on the effects of salamander larvae on isopods in stream pools. Freshwater Biology , 25: 451-459.

Huang, C., A. Sih. 1990. Experimental studies of behaviorally mediated indirect interactions through a shared predator. Ecology , 71: 1515-1522.

Kats, L. 1986. Natural history notes: Nerodia sipedon (northern watersnake) feeding.. Herpetological Review , 17: 61-62.

Kraus, F., J. Petranka. 1989. A New Sibling Species of Ambystoma from the Ohio River Drainage. Copeia , 1989(1): 94-110.

Niemiller, M., B. Glorioso, C. Nicholas, J. Phillips, J. Rader, E. Reed, K. Sykes, J. Todd, G. Wyckoff, E. Young, B. Miller. 2009. Notes on the Reproduction of the Streamside Salamander, Ambystoma barbouri , from Rutherford County, Tennessee. Southeastern Naturalist , 8(1): 37-44.

Niemiller, M., B. Glorioso, C. Nicholas, J. Phillips, J. Rader, E. Reed, K. Sykes, J. Todd, G. Wyckoff, E. Young, B. Miller. 2006. Status and distribution of the Streamside Salamander, Ambystoma barbouri , in middle Tennessee. American Midland Naturalist , 156: 393-399.

Petranka, J., A. Sih, L. Kats, J. Holomuzki. 1987. Stream drift, size-selective predation and the evolution of ovum size in an amphibian. Oecologica (Berlin) , 71: 624-630.

Petranka, J., A. Sih. 1987. Habitat duration, length of larval period, and the evolution of a complex life cycle of a salamander, Ambystoma texanum . Evolution , 41(6): 1347-1356.

Petranka, J. 1998. Salamanders of the United States and Canada . Washington, DC.: Smithsonian Institution Press.

Petranka, J. 1982. . Geographic variation in mode of reproduction and larval characteristics the small-mouthed salamander ( Ambystoma texanum ) in the east-central United States. Herpetologica , 38: 333-336.

Petranka, J. 1984. Breeding migrations, Breeding Season, Clutch Size, and Oviposition of Stream-breeding Ambystoma texanum . Journal of Herpetology , 18(2): 106-112.

Petranka, J. 1982. Courtship behavior of the small-mouth salamander ( Ambystoma texanum ) in Central Kentucky. Herpetologica , 38(2): 333-336.

Petranka, J. 1983. Fish predation; a factor affecting the spatial distribution of a stream-breeding salamander. Copeia , 1983: 624-628.

Scott, A., B. Miller, M. Brown, J. Petranka. 1997. Geographic distribution Ambystoma barbouri . Herpetological Review , 28: 155.

Smith, C., J. Petranka. 1987. Prey Size-Distributions and Size-Specific Foraging Success of Ambystoma larvae. Oecologica , 71(2): 239-244.

Watson, M., T. Pauley. 2005. Ambystoma barbouri . Pp. 603-605 in Amphibian Declines: The Conservation Status of United States Species , Vol. 1, 1 Edition. Berkeley, CA: University of California Press.