This laboratory study was designed to examine the response of a postfire ascomycete community to elevated temperatures and treatment intervals corresponding to those recorded during the burning of a tallgrass prairie. Aerated steam treatment of prairie soil samples (35, 40, 55, 70, 85, or 100 °C) for intervals of 60, 100, 140, or 180 s enabled us to examine the response of individual species comprising the carbonicolous ascomycete community.Simulation of a grassland fire by aerated steam treatment of prairie soils promoted the development of 20 species of ascomycetes. Generalists such as Sporomiella subtilis Ahmed and Cain occurred at high frequencies over most of the temperature range while specialists Podospora curvispora (Cain) Cain, Sordaria macrospora Awd., and Leptosphaeria sp. were important at only one temperature. Species diversity, richness, and number of species per sample were significantly affected by the temperature of the steam treatment. The temperature–treatment interval combination allowing for the greatest expression of diversity in the carbonicolous ascomycete community was 55 °C for 60 s. Since a grassland fire does not uniformly heat the soil surface, the environmental patchiness created by this physical perturbation may be an important factor in determining the composition of the carbonicolous ascomycete community in prairies.
Microbial Community Structure and Functional Potential in Cultivated and Native Tallgrass Prairie Soils of the Midwestern United States
