Seasonal occurrence of Conidia of Aquatic Hyphomycetes (Fungi) in Lees Creek, Australian Capital Territory

Abstract

The aquatic hyphomycete spora of an upland stream (Lees Creek) were sampled twice monthly by membrane filtration at two sites, the upstream one with native riparian vegetation and the downstream one with exotic pines. Physicochemical properties of the water were measured at each sampling. Conidia of 43 species were collected, of which 18 are undescribed and most species occurred at both sites. The peak concentrations of conidia occurred in late summer to early autumn and minimum concentration in winter. This contrasts with the autumn-winter maximum and summer minimum concentrations recorded for tree-lined streams of the Northern Hemisphere. These differences correspond with differences in seasonality of litter fall in the Northern Hemisphere compared with Australia. Analysis of variance showed significant differences between the two sites for concentrations of conidia of individual species and of total conidia. The magnitude of these differences was related to the time of sampling. Using multiple linear regression analysis, the occurrences of conidia detected at the up-stream site were best explained by water temperature; down-stream, rainfall and water temperature together explained most variance.