Migration plasticity in ungulates: will it translate in resilience to global change?

Migration is an important component of ungulate behavioural tactics that is tightly linked both to population distribution and to the function ungulates exert in ecosystems. The migration rate of several species has been observed to decrease, and climate change and anthropic pressure have been indicated as potential driving causes. The loss of migratory behaviour in ungulates could have paramount consequences on the ecosystems that encompass their seasonal ranges, on the one side, and affect population dynamics on the other.This talk has two main goals: first, to re-establish the link between migratory behaviour and emerging movement patterns, in ungulates; then, to assess the causes – or determinants- of migration by looking at multi-population movement datasets of large herbivores in temperate climates, specifically the European roe deer Capreolus capreolus and red deer Cervus elaphus. The analysis of movement trajectories through different methods allowed us to identify inconsistencies in the classification of migratory behaviour at individual level that we attributed to individual plasticity. We thus acknowledged the emergence of movement patterns other than residence and stereotyped migration, and expressed them through ‘indexes of migratoriness’. Finally, we have linked intrinsic factors (sex) and extrinsic conditions (e.g. topography, seasonality, canopy closure, plant productivity/NDVI) to parameters describing migration plasticity, i.e. migration propensity, distance and timing. We have found a strong relation between migration variability and sex-related and species-related life history traits. Thus, climate and landscape change might affect migratory behaviour of populations and species through complex responses. This talk will stimulate the discussion whether new knowledge on ungulate migratory behaviour should suggest management and conservation actions to favour and maintain migration in ungulate populations, or if instead should be used to acknowledge the change in movement patterns as a form of reversible adaptive behaviour, impossible to control.