Starting the stowaway pathway: the role of dispersal behavior in the invasion success of low-mobile marine species

Abstract

Despite the importance of dispersal behavior in the eco-evolutionary responses of species to global environmental change, its role in the invasion dynamic of stowaway invaders has been poorly studied, especially in low-mobile species (i.e. with direct development). Here we use peracarid crustaceans as a target group to understand the role that local dispersal plays in the initial stages of the stowaway pathway in species inhabiting transport hubs (specifically marinas). Thus, we performed field experiments to quantitatively explore differences in species’ propensity to disperse when comparing species with low and high invasion potential (considered here as the ability for successful anthropogenic dispersal). At the community level, we found that widespread introduced species (with high potential for invasion; HPI) exhibited higher propensity for local dispersal than closely related species that fail to spread (with low potential for invasion; LPI). From a functional perspective, high invasion potential, in synergy with omnivorous feeding and a tube-dweller lifestyle, was instrumental in determining differences in trait composition between assemblages that vary in their natural tendency to disperse. In addition to anthropogenic dispersal on ships, we show that unaided dispersal may play a crucial role at the beginning of the stowaway pathway, even in low-mobile species. Knowledge of dispersal behavior should be more fully integrated into research on managing the risk of this growing invasion pathway. This may help to predict rates of spread and provide new insights into the proximate causes of stowaway organisms’ invasion success.