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). (Green, 1956; Kraus and Petranka, 1989; Scott, et al., 1997)
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). (Kraus and Petranka, 1989; Petranka, 1998)
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). (Kraus and Petranka, 1989)
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). (Kraus and Petranka, 1989; Petranka and Sih, 1987; Petranka, et al., 1987)
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.
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. (Kraus and Petranka, 1989)
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). (Kraus and Petranka, 1989; Petranka, 1982a; Petranka, 1982b)
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). (Petranka, 1984)
Little is known about the parental investment of Ambystoma barbouri.
The exact lifespan of streamside salamanders is unknown.
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.
Ambystoma salamanders are thought to communicate primarily via chemosensation and tactile cues (in the form of courtship nudging) during the breeding season.
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). (Huang and Sih, 1991; Smith and Petranka, 1987)
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). (Kats, 1986; Petranka, 1983; Petranka, et al., 1987)
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). (Brodie, 1977; Brodie, et al., 1974; Huang and Sih, 1990)
green sunfish (Lepomis cyanellus)
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). (Kats, 1986; Petranka, 1983; Petranka, 1998; Smith and Petranka, 1987)
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.
There has been no evidence to suggest streamside salamanders have a negative effect on humans.
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). (Hammerson, 2004; Niemiller, et al., 2006; Niemiller, et al., 2009; Petranka, 1998; Watson and Pauley, 2005)
Katy Gardner (author), Missouri State University, Brian Greene (editor), Missouri State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
mainly lives in water that is not salty.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
An animal that eats mainly insects or spiders.
fertilization takes place within the female's body
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
chemicals released into air or water that are detected by and responded to by other animals of the same species
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
having more than one female as a mate at one time
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
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