Vertical Divergence of Cultivable Microfungal Communities Through Biocrusted and Bare Soil Profiles at the Tabernas Desert, Spain

We examined the depth-wise distribution of microfungi through 0–30 cm soil profiles under different surface types—cyanobacterial crusts, three lichen-dominated crusts, and non-crusted bare surface located at the north-oriented slope and sun-exposed plain at the Tabernas Desert, Spain. A total of 116 species from 60 genera was isolated using the soil dilution plate method. High ultraviolet and solar radiation, high temperatures and desiccation caused the dominance of species with the protective dark pigmentation and partly with the protective many-celled spore morphology in the majority of uppermost communities. At the same time, deeper layers were mostly inhabited by light-colored fungi producing a high amount of small thin-walled spores—thermotolerant Aspergillus spp. (at the depth of 1–5 cm) and mesophilic Penicillium spp. (at the depth of 10–20-cm, with the increase much more pronounced in the north-oriented profiles). Limited water infiltration in the fine-grained Tabernas soil causing the deposition of spores of aspergilli and penicillii at the depth of 1–10 cm most likely led to the substantial increase of isolate densities at these depths. Among environmental aspects, soil depth most strongly governed the microfungal communities, highly significantly influencing all their characteristics; meanwhile, habitat position and surface type significantly affected only the communities’ composition.