Determinants of Plant–Mycorrhizal Fungal Distributions and Function Under Global Change

As temperatures rise, plants are expected to shift their ranges to align with their abiotic niches. If plants do not encounter suitable mycorrhizal fungi in new habitats, however, these migrations may fail. We review the literature to describe how arbuscular mycorrhizal (AM) fungi, ectomycorrhizal (EM) fungi, and ericoid mycorrhizal (ErM) fungi currently vary within and beyond host plants’ ranges and how these mycorrhizal fungi shape plant ranges. We introduce a framework that predicts when plants are likely to encounter suitable mycorrhizal mutualists in new habitats. Critically, the probability of beneficial plant–mycorrhizal fungal interactions occurring depends on ( a ) plants’ specificity to mycorrhizal fungi, ( b ) abiotic similarity between historic and new ranges, ( c ) plants’ relatedness to new range plants, ( d ) geographic distance between historic and new ranges, and ( e ) alignment of plant and mycorrhizal fungal niches, all of which are affected by mycorrhizal guild. To conclude, we review research frontiers in the field of plant–mycorrhizal fungal interactions.