Effect of warming and nitrogen addition on the community composition and diversity of cultivatable fungi from the desert steppe of Inner Mongolia

To understand how to effectively manage a desert steppe environment during a period of warming and nitrogen deposition, the effects of nitrogen (N) addition and warming on the community structure and diversity of cultivatable fungi were studied. The dilution plate method was used together with the molecular analysis of 18S rRNA after the application of infrared radiation to simulate global warming and fungi were artificially fertilised for 6 years in a desert steppe with the dominant species of Stipa breviflora in Inner Mongolia. The results indicated that 17 fungal genera were isolated from the desert soil. N addition alone or with simulated warming led to a significant (P0.05) increase in the total number of cultivatable fungi from 6.70×105 colony-forming units·g-1 in the untreated control to 1.45×106 or 1.92×106 colony-forming units·g-1, respectively. Moreover, the community composition and dominant species changed with N addition. With N addition alone, the dominant fungal genera Aspergillus, Hypocrea, and Cladosporium were replaced by Fusarium, Alternaria, and Pseudogymnoascus, and the species richness, evenness, and diversity significantly increased. The effect of N addition with simulated warming increased the abundance of the dominant fungal genera Penicillium and Aspergillus, and another three dominant fungal genera were replaced by Fusarium, Alternaria, and Chromocleista. Combining N addition with simulated warming had no significant effects on the species richness, evenness, and diversity of cultivable fungi, compared with N addition alone.