Tiny but mighty: pollen of South Tyrol

Up to 20% of the South Tyrolean population is affected by pollen allergy. The pollen information service (PIS) is provided by the Biological Laboratory of the Agency of Environment and Climate protection. Besides publishing weekly pollen reports, producing pollen calendars for the region and providing a pollen forecast, the PIS is involved in other projects of this research-field. One of them is a study which focused on pollen concentrations in alpine valleys of South Tyrol. Therefore, the pollen concentrations of two alpine stations in Prettau and Grub (both located above an altitude of 1400 m) were measured during the period from 2019-2021. Results showed that the Seasonal Pollen Index (SPI) of the alpine stations was lower compared to the SPI of the nearby surveyed stations located at lower altitude in the main valleys. This could be due to the absence of pollen sources at a certain altitude and to a shorter vegetation period at alpine locations. Nevertheless, the phenomenon of long-distance transport of pollen by strong winds could also have impacted the concentration and species spectrum of pollen measured in these stations. Similar difference in pollen load correlated to the altitude had been found focusing on the pollen of only one species: the invasive Ambrosia artemisiifolia. In cooperation with a working group, the mean daily concentrations of Ambrosia pollen of five regions in Northern Italy were evaluated for the period 2000- 2023. The results showed that in the stations at higher altitude, the pollen concentration of Ambrosia was lower than in the stations located at lower altitude. Additionally, a significantly decreasing trend was observed in the stations of the lowlands around Milano. This finding can be linked to the accidental import of an invasive leaf-beetle species, Ophraella communa, which reduced the Ambrosia population because it feeds preferably on these plants