How introduced species affect coevolution in seed dispersal mutualisms?

Abstract

Species introductions are a major threat to biodiversity. Even if its impacts on the structure of mutualistic networks are increasingly known, its effects on coevolution between species are still poorly understood. Seed dispersal by animals is a key mutualism as it promotes the regeneration of plant communities, an important process to overcome the impacts of habitat loss and climate change. Although mediated by long coevolved species traits, seed dispersal interactions can rapidly respond to strong evolutionary pressure. Therefore, seed dispersal interactions could be under threat by the fast pace at which exotic species are introduced worldwide, changing patterns of selective pressures. A recent study showed that local and global seed dispersal networks have suffered a deep structural homogenization due to species introductions. We can, therefore, expect that both the indirect interactions between species and, consequently, the coevolutionary dynamics in seed dispersal systems have also been profoundly affected. In this project, we aim to understand whether and how introduced species affect the coevolutionary dynamics - potentially disrupting interactions - between plants and seed dispersers at two spatial scales, in local communities and at the global scale. To do so we will combine a comprehensive global dataset on seed dispersal networks, a coevolutionary model and a multilayer network approach, in which seed dispersal interactions at different locations will be connected by the dispersal of individuals between populations. With this project, we expect to move our current theoretical knowledge on coevolutionary dynamics in ecological networks to address one of the most pressing applied problems today: how introduced species affect coevolution between species and their interactions. (AU)