MYCOPHAGY IN SMALL MAMMALS - A COMPARISON OF THE OCCURRENCE AND DIVERSITY OF HYPOGEAL FUNGI IN THE DIET OF THE LONG-NOSED POTOROO POTOROUS-TRIDACTYLUS AND THE BUSH RAT RATTUS FUSCIPES FROM SOUTHWESTERN VICTORIA, AUSTRALIA

Three broad dietary categories-fungus, plant and arthropod-were identi fied from faecal samples of two species of small terrestrial mammal in forest vegetation in southwestern Victoria. Fungal material formed th e major component of the diet of the long-nosed potoroo Potorous trida ctylus throughout the year and of the bush rat Rattus fuscipes during autumn and winter. Fungal material was most abundant for both species during autumn and winter and significantly less common in spring and s ummer. These results confirm previous studies which found P. tridactyl us to be highly mycophagous throughout the year and R. fuscipes to be strongly mycophagous seasonally. Particular consideration was given to the composition of fungi in the diet. Fungal spores in faecal materia l were assigned to spore classes, which represent one or more fungal s pecies that have similar spore morphology. Twenty-four fungal spore cl asses were recorded, but for both animal species most of the fungi con sumed were hem seven major spore classes. The proportions of major spo re classes in the diet of both animals were generally similar, even th ough the composition of spore classes differed markedly across seasons . Minor differences between species in the fungi consumed may be relat ed to differences in selectivity, foraging, or microhabitat use. If fu ngal resources are limiting, competition for such resources may be imp ortant in this and other small mammal communities. The amount and dive rsity of hypogeal fungi consumed by the two animal species makes them both important spore dispersal agents in forest ecosystems. The capaci ty of R. fuscipes and other seasonally mycophagous mammals in this rol e may be more important than previously recognized, especially in habi tats where species of the Potoroidae are absent.