Here, we analysed data from a DNA-based survey of fungal communities in soils collected throughout Australia to observe relationships among soil fertility and the abundance of two arbuscular mycorrhizal fungal taxa that reportedly vary in function – the Gigasporaceae (putatively more important for nutrient uptake) and Glomeraceae (putatively more important for biotic stress). Relationships were assessed in three vegetation types – grasslands, forests and woodlands – to assess whether associations with soil fertility varied depending on carbon availability for arbuscular mycorrhizal fungi.