Successful use of a passive integrated transponder (PIT) system for below-ground detection of plethodontid salamanders

Abstract

Context Passive integrated transponder (PIT) technology allows for permanent and unambiguous marking of animals and has recently been adapted for locating tagged individuals in the field with portable detection systems. Aims We seek to assess the effects of PIT tagging on the growth and survival of plethodontid salamanders in the laboratory and to evaluate the effectiveness of this method for subterranean detection of salamanders in the field. Methods In a laboratory experiment, we assigned 36 Plethodon shermani to either a PIT tag or control group and compared survival and growth rates over the course of 9 weeks. For the field study, we implanted six Plethodon metcalfi with PIT tags and conducted surveys so as to determine their below-ground positions with a portable detector. Key results We found no effect of PIT tagging on either growth or survival in the laboratory. In the field, PIT telemetry resulted in an overall detection efficiency of 44%, with nighttime surveys yielding a greater detection efficiency than daytime surveys. This technique provided a significant improvement over traditional hand-capture because detected salamanders were rarely visible on the ground surface. Key conclusions Our study indicates that even these relatively small-bodied salamanders (range: 2.14–5.18 g) are capable of bearing PIT tag implants and confirms the results of previous studies that found no effect of PIT tagging on the health or survival of amphibians. This study further demonstrates that the use of a portable PIT detector can be an effective method for locating below-ground salamanders. Implications Because of the small size and long lifespan of PIT tags, we believe portable PIT detectors can provide researchers with an unprecedented level of detail for studies of the movement behaviour, spatial ecology and management of species that are small or otherwise challenging to detect and monitor with other techniques.