Moisture and competition alter soil biota effects on invasive Centaurea stoebe growth coincide with shifts in fungal communities

Soil microbes, such as root-associating fungal mutualists and pathogens, influence plant-plant interactions. Yet, the context-dependency of their effects remains poorly understood, hindering our ability to predict plant invasions. We targeted Centaurea stoebe, an invasive plant which is more successful in arid than mesic North American grasslands. We asked how the abundances of the arbuscular mycorrhizal (AM) fungi and potentially pathogenic fungi are moderated by soil moisture and if shifts in these guilds correspond with C. stoebe growth and competitiveness.