Seasonal Production of Hypogeal Fungal Sporocarps in a Mixed-Species Eucalypt Forest Stand in South-Eastern Australia

Abstract

The seasonal production of hypogeal fungal sporoearps was monitored over an 18 month period in a catchment of mixed-species euealypt forest in East Gippsland, Vietoria. During the study, sporocarps of one Ascomycete and 25 Basidiomycete species were collected from soil quadrats sampled sequentially around the bases of eucalypt trees- Sporocarps from these species varied in their dimensions and morphological characteristics. Productivity varied from 21 000 sporocarps ha-1 to 181 000 sporocarps ha-1 or 1.8 kg ha-1 to 8.3 kg ha-1 per month. The probability of occurrence of sporocarps was, on average, greater in midslope sites on a sheltered aspect than elsewhere within the catchment. The number of sporocarps produced varied over time, with a major peak in production occurring during May (late-autumn). This peak occurred mainly within gully sites, which supported on average a greater number of sporocarps than ridge or midslope sites, but a lesser weight of sporocarps. The distribution and productivity (probability of occurrence, number and weight) of sporocarps appeared to be associated with some environmental (soil) variables, but not the physical variables (host tree), that we measured. Sporocarps of some species fruited predominantly in ridge and slope habitats, some species fruited mainly in gullies, whereas others apparently showed no preference for fruiting in ridges, slopes and gullies. Thus, in forest catchments subject to land-management practices such as logging and fire, it may be important to retain undisturbed habitat throughout the topographic sequence to conserve a diversity of hypogeal species.