| Summary: | Environmental factors influencing the occurrence and community structure of soil yeasts in forests are not well studied. There are few studies dedicated to Southern Hemisphere soil yeasts populations and even fewer focused on temperate forests influenced by volcanic activity. The present work aimed to study the ecology of soil yeast communities from pristine forests influenced by different environmental factors (precipitation, physicochemical properties of soil, tree species, soil region, and season). The survey was performed in 4 northern Patagonian forests: 2 dominated by Nothofagus pumilio and 2 by Nothofagus antarctica. Yeast communities were described with ecological indices and species accumulation curves, and their association with environmental characteristics was assessed using multivariate analysis. Each forest site showed a particular arrangement of species as a result of environmental characteristics, such as dominant plant species, nutrient availability, and climatic characteristics. Cryptococcus podzolicus was most frequently isolated in nutrient-rich soils, Trichosporon porosum dominated cold mountain forests with low nutrient and water availability in soil, and capsulated yeasts such as Cryptococcus phenolicus dominated forest sites with low precipitation. The present work suggests that environmental factors affecting yeast communities may not be the current soil characteristics but the result of complex interactions of factors including natural disturbances like volcanic activity. Les facteurs environnementaux qui ont une incidence que la prévalence et la structure communautaire des levures terricoles sylvestres sont mal étudiées. On trouve peu d’études consacrées aux populations terricoles de l’hémisphère sud, et rares sont celles s’attardant a` l’influence de l’activité volcanique sur les forêts tempérées. Le présent ouvrage s’est voué a` étudier l’écologie des communautés de levures terricoles de forêts intactes subissant l’influence de divers facteurs environnementaux (précipitations, ...
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