Aquatic hyphomycetes from different substrates: substrate preference and seasonal occurrence

Abstract

Aquatic hyphomycetes occurring in an Australian upland stream (Lees Creek) were sampled from naturally submerged substrates derived from the riparian vegetation. Substrates sampled were bark and phyllodes of Acacia melanoxylon; bark, leaves and twigs of Eucalyptus viminalis; leaves of Pomaderris aspera; fronds of a fern, Blechnum nudum; and leaves of a sedge, Cyperus sp. A total of 47 species of hyphomycetes was detected overall, with maximum subsets of 34 species being recorded from eucalypt twigs and sedge leaves and the minimum number of 28 species being recorded from eucalypt leaves. The fungi showed significant substrate preferences, although no species was confined to a single substrate. Possible reasons for substrate preferences are advanced. The patterns of occurrence of the various fungal species were sufficiently distinct that most substrates could be predicted with a high degree of success from a knowledge of the fungal flora sampled from them. Patterns of occurrence varied with season, probably influenced by changing substrate availability and water temperature.