Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas
Abstract
How particular pathways of introduction of alien plants differ in terms of post-invasion success of species they deliver has never been rigorously tested. Pathways introducing alien species in the Czech Republic deliberately as commodities (direct release into the wild; escape from cultivation) result in easier naturalization and invasion than pathways of unintentional introduction (contaminant of a commodity; stowaway arriving without association with it).
The proportion of naturalized and invasive species among all introductions delivered by a particular pathway decreases with a decreasing level of direct assistance from humans associated with that pathway, from release and escape to contaminant and stowaway. However, those species that are introduced via unintentional pathways and become invasive are as widely distributed as deliberately introduced species, and those introduced as contaminants invade an even wider range of seminatural habitats.