Modelling mycorrhizal fungi dispersal by the mycophagous swamp wallaby (Wallabia bicolor)
Despite the importance of mammal-fungal interactions, tools to estimate the mammal-assisted dispersal distances of fungi are lacking. Many mammals actively consume fungal fruiting bodies, the spores of which remain viable after passage through their digestive tract. Many of these fungi form symbiotic relationships with trees and provide an array of other key ecosystem functions. We present a flexible, general model to predict the distance a mycophagous mammal would disperse fungal spores. We modeled the probability of spore dispersal by combining animal movement data from GPS telemetry with data on spore gut-retention time. We test this model using an exemplar generalist mycophagist, the swamp wallaby (Wallabia bicolor). We show that swamp wallabies disperse fungal spores hundreds of meters - and occasionally up to 1,265 m - from the point of consumption, distances that are ecologically significant for many mycorrhizal fungi. In addition to highlighting the ecological importance of swamp wallabies as dispersers of mycorrhizal fungi in eastern Australia, our simple modeling approach provides a novel and effective way of empirically describing spore dispersal by a mycophagous animal. This approach is applicable to the study of other animal-fungi interactions in other ecosystems.
The Swamp Wallaby 'Wallabia bicolor': a generalist browser as a key mycophagist
Mammal-macrofungal interactions are integral to ecosystem function in landscapes dominated by ectomycorrhizal (EM) plants. EM fungi, critical symbiont's with forest plants, produce sporocarps (fruit bodies) which are an important food resource for a variety of mammals. These mammals in turn play an important dispersal role, particularly for truffle-like (below-ground fruiting or hypogeous basidiomycetes) sporocarpic fungi that do not actively discharge their spores (sequestrate). This thesis examines interactions between truffle-like fungi and a non-specialist, mycophagous marsupial, the swamp wallaby 'Wallabia bicolor'. The availability of truffle-like fungi sporocarps as a food resource for mycophagous (fungus-feeding) mammals, the macrofungal diet of the swamp wallaby, and gut-retention and potential dispersal of macrofungal spores by swamp wallaby are examined.
New Guinean bandicoots: new insights into diet, dentition and digestive tract morphology and a dietary review of all extant non-Australian Peramelemorphia
Little is known about the diets and ecology of New Guinea's 14 bandicoot species. In order to better understand the diet and digestive morphology of these marsupials, we reviewed the literature, studied the dental morphology, conducted analysis of gastrointestinal contents, and measured the digestive tracts of: Echymipera clara, E. davidi, E. kalubu, E. rufescens, Isoodon macrourus, Microperoryctes ornata, M. papuensis and Peroryctes raffrayana. These species consume a mix of fungi, insects and plant material that is broadly consistent with the omnivorous diet characteristic of most Australian bandicoots; however, morphological observations reveal variation between species that likely reflect finer-scale differences in diet. Dental morphology suggests a wider variety of diets (insectivore, omnivore, frugivore) than on the Australian mainland (mostly omnivore). Dissections and measurements of the digestive tract of seven New Guinean species indicate variation linked to diet. The relatively short caecum in all New Guinean species, but especially in E. clara and E. kalubu, is particularly suggestive of limited consumption of fibrous plant material; the relative length of the large intestine suggests variable capacity for water reabsorption. Our dietary data also suggest that some of these species also play an important role in the dispersal of hypogeous fungi.