Roberts, Alexandre (Princeton University). Mentor: Eric Liebgold (University of Virginia). The effects of perceived mortality risk on above-ground habitat selection in a terrestrial salamander.

Abstract: Habitat selection in foraging animals is strongly influenced by each habitat's food availability, and the animal's mortality risk and physiological cost in the habitat. Plethodon cinereus , a small, lungless, entirely terrestrial salamander, displays nighttime plant-climbing behavior despite indications that water loss is a physiological constraint for P. cinereus in a raised habitat that is more exposed to wind. We tested the hypothesis that plant-climbing is the result of lowered mortality risk on plants by causing autotomization of each salamander's tail to simulate a failed predation attempt and tracking it at night with fluorescent powder tracking. We found that tail-clipping increased the maximum and average heights climbed. We also measured prey abundance on and off the ground, and found more prey (both by numbers and weighted for size) on the ground than on plants. We therefore conclude that the plant habitat is used for its reduced risk of predation despite reduced foraging rate and increased physiological cost, in a way consistent with a habitat selection model balancing mortality risk and net metabolic gain (Gilliam and Fraser 1987).