What drives differences in arbuscular mycorrhizal fungal communities among plant species?

Plant species can influence communities of arbuscular mycorrhizal fungi (AMF) by hosting different AMF taxon identities and/or richness. We used presence/absence data from a recent global survey of AMF communities to assess how often AMF communities differ among plant species, and to explore whether differences result from dissimilarities in AMF taxon identity or richness. We found that AMF communities clustered among plant species in 24% of sites, and that plant species were more likely to differ in AMF taxon richness (23% of sites) than the particular taxa with which they associate (5% of sites). Overall though, the variation in both AMF richness and identity was often as great within as between plant species, suggesting that plant species identity may be less important for structuring local AMF communities than other factors, such as environmental conditions, fungal interactions or even stochastic distributions of AMF. This has implications for how we should view plant-AMF interactions and community patterns.