A second Artemisia pollen peak in autumn in Vienna: reaching the point of no return?

Abstract

AbstractThe Artemisia (mugwort) pollen season usually ranges from July until September, with one peak period around mid-August in Vienna (Austria). During the last decade, Artemisia pollen was also recorded later in September. This pattern was concluded by a significant peak pollen concentration day in autumn of 2023, which exceeded the usual summer peak pollen concentration day. The Artemisia pollen data from Vienna for the last ten years (2014–2023) were therefore analysed for a temporal trend. In addition, weather data from Vienna (temperature, precipitation, and relative humidity and sun hours) were retrieved and analysed to find a possible association with Artemisia pollen indices. No significant trend could be observed regarding the Artemisia pollen season parameters and no correlation was found between the weather data and the Artemisia pollen integrals during summertime. However, a significant positive correlation was found between higher temperatures during autumn and the occurrence of Artemisia pollen during this time. This suggests that a significant change in the Artemisia pollen season can be expected during years with a mild, summer-like autumn. Until now, it is not clear which species of Artemisia cause the pollination in autumn. A. annua and A. verlotiorum are two major suspects that could have established themselves in Vienna, but further evidence is needed. Considering the impact of global climate change, the shift in the pollen season for Artemisia described in this study could represent a point of no return.