Response of Antarctic soil fungal assemblages to experimental warming and reduction of UV radiation.

Abstract This paper reports the effects of nutrient
availability, UV radiation and temperature on the taxa
composition and abundance of Antarctic soil mycobiota.
Two sites at Edmonson Point were studied: the first
was poor in nutrients, near the glacier, and the second
was close to bird nesting sites. The highest abundance of
soil fungi was recorded at the site adjacent to the bird
nesting sites. Phoma herbarum was the most abundant
taxon. Lecytophora lignicola and Ascotricha erinacea are
new records for continental Antarctica. The fungal
assemblage from the nutrient-deficient site was characterized
by a dominance-diversity curve approaching the
broken-stick model, the assemblage from the soil influenced
by birds was characterized by a lognormal distribution.
Plastic cloches were used in experiments
designed to assess differences in fungal assemblages
subjected to altered temperature and/or UV exposure.
Dominance-diversity curves and diversity values of soil
fungal mycobiota were compared in their natural condition
as compared with manipulated conditions. Under
the walled cloches, at both sites, artificial warming led to
stress on Antarctic soil fungal assemblages. In contrast,
UV protection led to a higher equilibrium in the
assemblage structure. On the basis of the results
obtained, it could be proposed that UV radiation is the
most important limiting ecological factor for soil mycobiota
in continental Antarctica.