Variations in pollen calendars along time at Malaga (southern Spain)

Abstract

Pollen calendars are graphical representations that summarize the general annual dynamics of the more abundant airborne pollen types detected in the atmosphere of a certain location. To elaborate them, it is recommended to have continuous pollen sampling data from a period of, at least, 5 years in order to such pollen calendar be representative. However, the annual pollen dynamics can suffer changes in a medium or long term due to climate and land use changes, so the pollen calendars can therefore, show variations over time. The aim of this study was to detect whether or not changes have occurred in the pollen calendar of Malaga city during a 30-year period, as well as to analyze their possible causes. The aerobiological data were obtained by means of a Hirst-type volumetric pollen trap installed on the roof of the Faculty of Sciences, University of Malaga. Pollen samples were mounted and counted following the methodology proposed by the Spanish Aerobiology Network. A pollen calendar was elaborated for each 10-year period using the AeRobiology R package. Despite the three pollen calendars obtained were elaborated for the same sampling location, there were some important changes in the intensity and temporality of the airborne concentrations detected for some pollen types. These changes can be related to variations in the land uses near the city and temperature variations due to climate change. Pollen calendars should be updated along time in order to maintain their utility, given that it is possible to find some trends in the temporality and intensity of the pollen season of some taxa that can modify substantially this graphical representation.