Pollen distribution at high elevation in Switzerland: Evidence for medium range transport

Abstract

Since Switzerland has a complex topography with high mountains it was very uncertain how much and what kind of pollen can be found at high elevations. In order to study the content of air masses at high elevation a Burkard Seven Day Recording Volumetric Spore Trap was installed at the meteorological station at Gütsch (alt. 2300 m) in the Swiss Alps. Although there are no trees at all at this elevation it is amazing how much tree pollen is found. With the exception of Alnus viridis most of this pollen is transported across the Alps. Special attention is given to the pollen of Castanea which can serve as a real tracer, since this pollen originates exclusively from the southern part of Switzerland (Tessin). Grass pollen, on the other hand, has local sources, even at this elevation, once the snowy season has ended. Grass pollen and pollen of weeds, therefore, need not have been transported. The surprisingly high amount of pollen observed may also have a relevance for people with pollen sensitization because generally it is assumed that hayfever symptoms decrease quickly with increasing elevation.