Redundancy among mammalian fungal dispersers and the importance of declining specialists

- Fungi disproportionately dispersed by threatened mammals in Australia.
- Decline in fungal dispersers has unknown consequences for fungal diversity.
- Redundancy among mammal fungal generalists is unclear due to bias in data.

Hypogeous sequestrate (truffle-like) fungi rely primarily on consumption by mammals for dispersal. Most truffle-like fungi are ectomycorrhizal, making mammalian dispersers essential to the maintenance of plant-fungal relationships, soil fungal diversity and ecosystem functioning. Australia has the highest current global rate of mammalian extinctions, including important fungal specialists within the family Potoroidae. Knowing the relative importance of different mammal species as dispersers helps us to understand how this loss in mammal diversity could affect plant-fungi interactions and fungal diversity. Despite detecting a sampling bias in the literature, our meta-analysis confirms that mammals with fungal specialist diets contribute disproportionally more to the potential dispersal of fungi than other mammals within Australia. Three mammal species with generalist diets also consumed fungi at comparable rates to fungal specialist species and, importantly, persist in many areas where fungal specialists are now absent. These results highlight the significance of mammals, particularly fungal specialists, for maintaining diverse ectomycorrhizal fungal communities.