Nomadic movement in tropical toads

摘要: Dispersal is a critical aspect of the biology most organisms, but movement patterns are poorly known for animals. Knowledge allows biologists to construct realistic spatial models, either theoretical or empirical purposes. Cane toads (Bufo marinus) have high survival rates (30–70% per annum in Australia), very low recapture over long periods marking studies, suggesting that they may be nomadic. Here we model cane determine whether move nomadically. Using radiotracking, quantified movements 64 toads, at two widely separated locations northern Australia. We established toad were indeed nomadic by comparing real with those generated an individual-based, correlated random walk selected randomly from distributions parameters. In wet season, both locations, similar model, indicating moved nomadically during this time year. During dry season used smaller area and travelled less straight paths than predicted model. Nomadic more common extensive although some individuals all times To provided good description term, compared observed disappearance mark-recapture study conducted one our sites, There was agreement between these methods measuring movements. Previous studies indicated food availability lowest desiccation risk predation highest when costs due desiccation, energy limitation lowest.