Aquatic hyphomycete communities in the River Teign. II. Temporal distribution patterns

Abstract

Conidial frequencies in river-water from Nov. to Feb. and frequencies of occurrence of aquatic hyphomycetes on randomly sampled leaves from Oct. to Feb. were determined at three sites. Total number of conidia l−1 decreased from Nov. to Feb.; the magnitude of change was greater in a downstream direction. Based on relative conidial frequencies the five top-ranked species in Oct. were replaced by five different species by Feb. at Site III, while four of five top-ranked species were replaced at Site II. Fewer replacements occurred at Site I. On randomly sampled leaves at Site III, only Geniculospora inflata remained among the five top-ranked species from Oct. to Feb. Tetrachaetum elegans, Flagellospora curvula, Lemonniera terrestris and Lunulospora curvula were replaced by Articulospora tetracladia, Alatospora acuminata, Clavatospora longibrachiata and Clavariopsis aquatica. With respect to temporal distribution patterns, individual aquatic hyphomycete species fall along a gradient, the boundaries of which are set by species whose population sizes vary from considerable to undetectable, e.g. Flagellospora curvula, Lunulospora curvula, and species with consistently detectable populations, e.g. Clavatospora longibrachiata.