Abstract

Aggressive interference can be an important expression of competitive interactions within and among species. We studied potential interference between two similar-sized, sympatric species of woodland salamander. The Pigeon Mountain Salamander, Plethodon petraeus, occurs in habitat patches of rocky outcroppings along a restricted area on the eastern flank of Pigeon Mountain in northwestern Georgia. This species is relatively rare in the intervening areas of forest-floor habitat, which is occupied by a similar-sized, potential competitor, the Slimy Salamander (Plethodon glutinosus). Both species exhibited aggression and defended territories against conspecifics and heterospecifics in laboratory-based encounters. Individuals of P. glutinosus were superior in aggressive encounters with individuals of P. petraeus. Coexistence of the two species occurs because habitats are partially exclusive. There is enough habitat overlap, however, to generate possible interspecific competition. We hypothesize that the presence of territorial, aggressive P. glutinosus in areas between habitat patches may influence interpatch dispersal by P. petraeus.