New Insights on Atmospheric Fern Spore Dynamics

Pteridophyte airborne spores are scarcely represented worldwide compared to fungal spores or even to pollen grains. Through different studies, 81 taxa were identified in the atmosphere from different sampling points around the world with greater number of taxa in tropical and subtropical areas of Asia, America and Africa, the areas where pteridophytes have the greatest estimated diversity. Higher annual levels and higher daily concentrations were also found in these tropical and subtropical areas. Seasonal distribution of spores varied depending on the sampling site, with the highest levels in temperate areas occurring between late spring and early autumn, while in tropical and subtropical areas they were distributed throughout the year. Hourly spore concentrations were located in the central hours of the day. Airborne fern and lycopod spores generally appeared to be positively influenced by temperature and sunshine hours and negatively by rainfall, relative humidity and wind speed. The study of aerovagant spores has direct application in medicine, as a consequence of the allergenicity of some spore types, mainly in tropical and subtropical areas of Asia and in forensic palynology and criminology helping to the resolution of certain police cases.