Competitive Hierarchy in Post-Fire Ascomycetes

SUMMARY

Inability to compete directly with other members of the carbonicolous community is examined as a factor contributing to the stratification of fungal sporocarp appearance in a heterotrophic succession following prairie burning. Evidence is presented that late successional species of carbonicolous ascomycetes from a prairie burn are uniformly antagonistic to species appearing earlier in the sere. Rapidly developing species such as Gelasinospora calospora, Podospora curvicolla, P. glutinans, and Sordaria fimicola were inhibited by diffusable substance(s) produced by Podospora pilosa, a slower-growing and later-sporulating form. Rate of colony growth was not always related to the order of appearance of post-fire ascomycetes. The authors suggest that the evolutionary outcome of interference competition among post-fire-ascomycete populations is a pattern of competitive hierarchy in which late-successional species are increasingly capable of dominating earlier-appearing species.