Individual and among-population variation in dispersal-related traits in Natterjack toads

Recent publications on animal conservation called out the need to account for individual and among-population differences in dispersal. Despite the demonstrated links between personality traits and dispersal behavior, most studies of local adaptation have focused on dispersal capacity through variation in morphology and physiology. Ephemeral habitat patches generally favor dispersal capacity, whereas loss and increasing isolation of the patches can select against dispersal capacity. In this study, we explore whether populations of Natterjack toads (Bufo calamita) have evolved different morphologies, physiological performance and personality traits in response to the spatial arrangement of their habitat. First, we studied the consistency and intercorrelations of behavioral traits in order to test for the possible existence of personality, which so far has been largely ignored in the study of amphibians. Second, we assessed levels of population differentiation in candidate personality traits and dispersal capacity. The toadlets in this study originated from populations with different degrees of isolation, due to distance from other populations and resistance of the surrounding landscape, and with different dynamics of the subpopulations. We used two cohorts of toadlets, one raised in a common environment and the other collected in the field. We found consistency and correlations between the behavioral measurements, suggesting the possible existence of personality linked to mobility. The higher locomotor performance in toadlets from the metapopulations in the low-resistance landscape compared with those from the isolated populations indicates local adaptation in dispersal capacity. Yet, we could not demonstrate that differences in behavior can be explained by local adaptation in dispersal-related traits.