Community structure of yeast fungi in forest biogeocenoses

The results of longterm studies of yeasts inhabiting soil, plant surfaces, and plant residues in typical subboreal forests of the European part of Russia are summarized. The cell number and species diversity of yeast communities in the array of substrates corresponding to succession stages in plant residue decomposition are shown to steadily decline. Each stage is characterized by its specific set of dominating species. The yeast diversity in forest biogeocenoses is shown to surpass that in other geographic zones. This manifests itself in a greater number of species occurring in similar arrays of substrates, in the absence of conspicuous dominants on the biogeocenotic level, and in a higher differentiation of the yeast population with respect to its habitat type. The forest yeast populations are also characterized by a high diversity of yeasts of ascomycetous affinity and of the anamorphic stages of Taphrinales and Tremellales and by the presence of typical pedobiont species (except Lipomyces spp.).