Abstract
Exotic plants can escape from specialist pathogenic microorganisms in
their new range, but may simultaneously accumulate generalist pathogens.
This creates the potential for pathogen spillover, which could alter
plant-competitive hierarchies via apparent competition. To assess the
potential for and consequences of pathogen spillover in invaded
communities, we conducted a community-level plant-soil feedback
experiment in experimental communities that ranged in the extent of
exotic dominance, using next-generation sequencing to characterize
sharing of putatively-pathogenic, root-associated fungi (hereafter,
‘pathogens’). Exotic plants outperformed natives in communities, despite
being subject to stronger negative plant-soil feedbacks in monoculture
and harboring higher relative abundance of pathogens. Exotic plants made
more general associations with pathogens, making them more prone to
sharing pathogens with natives and exerting apparent competition. These
data suggest that exotic plants accumulate generalist pathogens that are
shared with native plants, conferring an indirect benefit to exotic,
over native plants.