Abstract: Understanding how the spatio-temporal variation in landscapes affects species is a priority in conservation biology. Anthropogenic modifications, such as roads, are prominent and frequent forms of landscape variation worldwide. The dramatic increase in population density has been one of the most pervasive road effects. This expansion is driven primarily by two contrasting demographic mechanisms: 1) increased recruitment and establishment of propagules, or 2) favorable conditions for growth and survival of adults. This project will compare these mechanisms using experiments, observations and matrix models in a biodiversity hotspot that has been subject to increasingly denser road networks: the Brazilian Cerrado (a Neotropical savanna). Model organisms will be Atta leaf-cutter ants, a keystone Neotropical species imposing major impacts on plant communities and ecosystem properties. The project will determine population and landscape level effects of roads to predict Atta expansion, helping to manage their exacerbated effects and to preclude dramatic changes in this heavily altered ecosystem.