Testing Assumptions in the Use of PIT Tags to Study Movement of Plethodon Salamanders
Studying the movements of organisms that live underground for at least a portion of their life history is challenging, given the state of current technology. Passive integrated transponders (PIT tags) provide a way to individually identify and, more recently, study the movement of smaller animals, including those that make subterranean movements. However, there are widespread assumptions of the use of PIT tags that remain problematic. We tested the effects of PIT-tag implantation on growth and survival, along with the effects of electromagnetic fields for reading PIT tags on behavior, of the smallest salamander that has been PIT-tagged: the Red-Backed Salamander. We found no effect of PIT tags on growth or survival. Using a mesocosm experiment, we also found that electromagnetic effects associated with reading PIT tags, had no effect on salamander behavior. Further, we describe a novel PIT antenna and soil mesocosm experimental arena for studying belowground movements of woodland salamanders. Collectively, these studies suggest that the use of PIT tags do not influence the growth, survival, or behavior of Red-Backed Salamanders. Given the challenges of studying salamanders that live underground and the impending changes in climate and landscapes, this research suggests that PIT tags remain a viable tool for studying the movement ecology of salamanders under global change.Abstract
The custom mesocosm experimental design illustrating the antennas (gray) and the individual mesocosms (blue) built to test the influence of electromagnetic fields on Red-Backed Salamander (Plethodon cinereus) behavior.
The custom antenna (gray) and the soil mesocosm (blue) built to track Red-Backed Salamanders (Plethodon cinereus).
Red-Backed Salamander (Plethodon cinereus) growth during a 14-wk experiment following PIT-tag implantation (8 × 1.25 mm, 0.024 g, Biomark Inc.; 1.7–4.3% of body mass). Bars represent standard deviation.
Vertical locations, as distance from surface (cm), of three male Red-Backed Salamanders (Plethodon cinereus) tracked vertically in soil mesocosms in a laboratory over 1 mo in January 2016. Upper and lower bounds represent the range of antenna detection within the mesocosm and are a product of antenna current and electromagnetic environmental noise. Vertical bars that overlap represent an individual tracked twice on the same day.
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