Abstract
Regional, local, and seasonal distribution of soil culturable microfungi in the Arava Valley, Israel, was examined along altitudinal and latitudinal gradients. A total of 198 species from 86 genera were isolated using the soil dilution plate method. Melanin-containing species with large multi-cellular spores dominated the majority of microfungal communities, while species with picnidial fruit bodies mostly prevailed in the northern part of the Arava Valley located at 190 m below sea level. Aspergilli (mainly Aspergillus fumigatus) and teleomorphic ascomycetes comprised the basic part of thermotolerant mycobiota obtained at 37 °C. The soil at the northern part of the desert held the highest number of microfungal isolates and, at the same time, was characterized by significantly lower species richness. The open sun-exposed localities harbored a significantly higher number of species than the localities under shrub canopies. Isolate density displayed the opposite trend and was significantly lower in the open than in shrub localities. The mycobiota characteristics such as species composition, contribution of major groupings to mycobiota structure, diversity level, and isolate density showed significant correlations with measured edaphic parameters-organic matter content, water content, pH, and especially, with electrical conductivity. Among the environmental aspects, locality position along altitudinal and latitudinal gradients accompanied by locality type (open sun-exposed or under shrubs), strongly influenced the community's characteristics, thus demonstrating the effect of the unique altitudinal position of the northern part of the Arava Valley as well as the ability of microfungal communities to be sensitive to the microscale environmental variability.