Behavioral Response of the Endangered Salamander, Ambystoma Altamirani, to the Cues of a Native Snake Predator and a Nonnative Trout Predator

Introduced trout are a threat to native salamander populations. The ability of native salamanders to behaviorally respond to the presence of nonnative trout may be important in allowing their populations to persist in the presence of the nonnative predators. We experimentally examined whether adult and juvenile Ambystoma altamirani behaviorally respond to chemical cues from nonnative Rainbow Trout (Oncorhynchus mykiss) and a native garter snake (Thamnophis scaliger). Ambystoma altamirani did not respond to O. mykiss cues but increased activity in the response to T. scaliger cues. Ambystoma altamirani was less active when vegetation was present and this effect was greater in the presence of predator cues. There were no seasonal differences in activity. In conclusion, we demonstrated that A. altamirani responds to native snake predator cues but not to nonnative trout cues. It is unclear if naïve populations of A. altamirani from fishless streams will evolve antipredator responses to O. mykiss. Unfortunately, the inability of A. altamirani to coexist with O. mykiss in stream reaches where O. mykiss have already been introduced does not bode well for such a possibility.