Stranger danger: emerging biosecurity risk from fungus inoculation and cultivation

When non-native fungal species or non-native genotypes of a native species are introduced into a new region they can sometimes become invasive, altering the species and genetic composition, and the functioning of resident communities. There is an ever-increasing risk of escapees into the natural environment through human activity, including overlooked introduction pathways, intentional introductions as mycorrhizal inoculum or inoculation accidentally from an increase in cultivation of edible fungi in outside environments. In each case guidelines and regulation are absent or weak increasing the risk of invasion, which presents a biosecurity risk that governments need to address. There are lessons to be learned from plant and animal biology about invasive species where there has been a long history of invasion from imported exotic and cultivated plants in particular. Here we highlight some of the problems arising from the establishment of alien fungi as species and strains or genotypes in new regions, and call for urgent introduction of guidance and stronger regulation to protect native fungal biodiversity and their habitats from the harmful consequences of non-pathogenic fungal invasions. This is crucial to meet the ambition of Global Biodiversity Framework targets for reducing the impact of invasive species.