Belowground interactions can affect plants either directly or indirectly via their associated mycorrhizal fungi. However, few studies have experimentally examined the consequences of interspecific root interactions for these important mutualists in the field. We used a trenching experiment to examine how belowground interactions between pinyon pine and one-seed juniper affected the ectomycorrhizal (EM) fungal communities of pinyon pine. Three major findings emerged: (1) pinyons responded to the reduction of juniper roots with a near doubling of fine root biomass in just two years, (2) this increase in pinyon roots translated into a potential two-fold increase in EM abundance, and (3) the EM fungal communities of trenched trees differed [...]
