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Yeast isolates from soil samples collected from a latitudinal gradient (>77 degrees S to >64 degrees N) were subjected to multivariate analysis to produce a statistical foundation for observed relationships between habitat characteristics and the distribution of yeast taxa (at various systematic levels) in soil microbial communities. Combinations of temperature, rainfall (highly correlated with net primary productivity), and electrical conductivity (EC) could explain up to ca. 44% of the distribution of the predominant yeast species, rainfall and pH could explain ca. 32% of the distribution of clades in the most common orders (Filobasidiales and Tremellales), whereas vegetation type (trees, forbs, and grass) played the same role for orders. Cryptococcus species with appropriate maximum temperatures for growth predominated in most soils. Cryptococcus species in the Albidus clade of the Filobasidiales predominated in desert soils; Cryptococcus species of other clades in the Filobasidiales and Tremellales predominated in wetter and more-vegetated soils, with Tremellalean species favored in soils of lower pH or higher EC. The predominance of Cryptococcus species in soils has been attributed to their polysaccharide capsules, particularly important when competing with bacteria in arid soils.

Fungal biodiversity in Antarctic terrestrial ecosystems increases with the availability of water and energy, but cannot now be precisely described because of problems with identification and questions as to what organisms are truly indigenous. Yeasts probably predominate on continental Antarctica, while other microfungi usually do so in maritime and sub-Antarctica. Lists of nematophagous species and of microfungal species reported from maritime and sub-Antarctica are given. The ecological roles of these fungi are worthy of further research. The ability of common airspora and pathogens to survive and colonize should be investigated.

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