Temporal variations in the diversity of airborne fungal spores in a Mediterranean high altitude site

Abstract Relationships between meteorological factors and airborne fungal spore concentrations at high altitudes are virtually unknown. We used cross-correlation analyses to test the relationships between daily variation in meteorological factors (i.e., temperature, humidity and wind speed) and airborne spore concentration, diversity (Shannon and Simpson indices) and evenness (Pielou index) in an Apennine high altitude site (Gran Sasso Massif, 2117 m elevation). Daily average concentration of spores in this high altitude site was much lower than that observed at a low altitude site in the same area, which can be explained by the environmental conditions at high altitudes. We found that diversity and evenness tended to be negatively correlated with temperature and positively with humidity and wind speed with some delay, whereas abundance tended to be positively correlated with temperature and wind, but negatively with humidity. These relationships can be explained by the fact that rain increases turnover by removing dry spores of Cladosporium (the most abundant taxon) and aerosolizing wet ones. The high dominance of the most abundant taxon is a reflection of the extreme climatic conditions at high altitudes.