Habitat and temporal differences among soil microfungal assemblages in Ontario

A survey of the soil microfungi in the A horizons of soils taken from four sites (deciduous forest, cedar forest, old field, and alfalfa field) in Cen tral Ontario at three times (May, June, and August) in one year was conduct ed to determine habitat and temporal differences of fungal assemblages. App roximately 70 species of fungi were identified. In all habitats, species in the genera Penicillium, Acremonium, Talaromyces, Cladosporium, Cunninghame lla, and Paecilomyces were isolated most frequently. Cedar forest soils sho wed the lowest species turnover with time, and Aspergillus fumigatus (Fres. ) was consistently one of the most abundant species throughout the sampling period. Total fungal abundance increased over the sampling period in cedar forest soils, a trend not observed in deciduous forest soils. Fungal abund ance, as well as the total number of species, in soils from the alfalfa fie ld and old field sites decreased in August. Narrow-amplitude, broad-amplitu de, and occasional species were characterized. Results are discussed with r eference to the biotic and abiotic factors that may influence fungal occurr ence and abundance.