CONICET | Buscador de Institutos y Recursos Humanos

The introduction of certain species of exotic plants may generate habitat modifications that in turn increase the predation risk for prey, either by making the prey more conspicuous, by offering perches to predators or by limiting suitable refuges. We compared predation pressure and escape behavior of two sympatric lizard species (Liolaemus wiegmanniiand L. multimaculatus) inhabiting forested and nonforested grasslands of the pampasic coastal sand dunes of Argentina. Predation pressure was evaluated by measuring the abundance of avian predators and calculating the predation rate on lizard plasticine replicas. Escape behavior was studied by searching for lizards in the field. Once a lizard was sighted we recorded flight initiation distance (FID; that between the observer and the lizard before it started escaping) and the microhabitat used as refuge. Both lizards prefer refuges in native plants, but when they are scarce Acacia longifolia functions as alternative refuge. In forested habitats sand-burying behavior is a complementary strategy used by L. multimaculatus to avoid predation. FID of L. wiegmannii was greater in forested habitats than in nonforested ones, confirming the assumptions of theoretical models of escape behavior. By contrast, L. multimaculatus showed a short FID in forested habitats, mostly because sand-burying behavior allows this species to hide ??beneath their feet?? reducing risks typically associated with exposed areas. Plasticity in antipredatory behavior suggests that these lizards could learn to recognize predators and develop a suitable antipredatory behavior. We conclude that increased predation pressure and structural alterations of the habitat generated by exotic trees of A. longifolia affect the decisions that determine how, when and where these lizards flee.