Urban remnant size alters fungal functional groups dispersed by a digging mammal

Digging animals perform many ecosystem functions, including soil turnover and vectoring fungi, particularly mycorrhizal fungi. However, these animals are also susceptible to the impacts of urbanisation, resulting in altered ecosystem processes. Some digging mammals, such as the omnivorous quenda (Isoodon fusciventer), a medium-sized marsupial bandicoot endemic to southwestern Australia, persist in urban landscapes and may play important roles as fungal vectors. This paper examines the fungal community in quenda scats from natural vegetation remnants within a fragmented urban landscape to ask: are quenda acting as vectors for a functionally diverse fungal community?; what fungal functional types are being vectored?; and does remnant size impact fungal species richness and composition vectored by quenda? We sequenced 53 scat samples collected from remnants and found that quenda disperse a functionally diverse fungal community, with 31% of the molecular operational taxonomic units (OTUs) putatively mycorrhizal. Fungal OTU richness was greatest in scats from smaller remnants due to higher mean relative abundance of saprotrophs, pathogens and yeasts. Fungal OTU richness of ectomycorrhizal fungi, critical for plant growth, were found at a higher abundance in larger remnants. Fungal composition was affected by remnant size, type and condition of vegetation, and soil type. Our results indicate that maintaining digging mammal populations within urban landscapes may assist with dispersal of fungi that facilitate fungal-plant interactions, contributing to ecosystem health. These results are important to understand the complex ecological implications of urbanisation, and how remaining mammals are critical in maintaining ecosystem processes within the urban land-use matrix.