Plant coexistence mediated by arbuscular mycorrhizal fungi

Recent research has indicated the importance of arbus-cular mycorrhizal fungi (AMF) in mediating plant coexis-tence. Coarse-scale studies compare the effects of the presence versus absence of AMF on plant coexistence, a phenomenon that is most relevant in early succes-sional ecosystems where AMF are patchily distributed. By contrast, fine-scale studies investigate interactions that might occur once AMF have developed more fully within ecosystems, and most plants come into contact with AMF. Whereas coarse-scale effects are well under-stood, our understanding of fine-scale factors is just developing, as a result of investigations into AMF– plant specificity, AMF species richness, shared mycelial networks, and plant–AMF feedback effects. Further research into these areas will provide a better under