Mammal mycophagy and fungal spore dispersal across a steep environmental gradient in eastern Australia

Abstract

We examined changes in the types of fungi consumed by six species of small mammals across a habitat gradient in north-eastern New South Wales that graded from swamp, to woodland, to open forest and then to rainforest. All mammals ate some fungus, but only bush rats ('Rattus fuscipes') regularly did so, and their diet included most of the fungal taxa that we identified across all mammals in the study.The composition of bush rat diet changed significantly with each change in habitat from woodland, to forest, to rainforest. In particular, there was a significant difference in the diets of rats caught either side of the open forest-rainforest ecotone, which marks the change in fungal community from one dominated by ectomycorrhizal fungi, to a community dominated by arbuscular mycorrhizal fungi. Movement patterns of bush rats living around the open forest-rainforest ecotone suggest that they transport fungal spores between these contrasting fungal communities. Therefore, bush rats have the potential, by way of spore dispersal, to influence the structure of vegetation communities.