Temporal and spatial variability in allergy-triggering phenological phases of hazel and alder in Czechia

Abstract

Pollen grains of alder (Alnus glutinosa), hazel (Corylus avellana) and birch (Betula verrucosa) belong to the most important allergens not only in the Czech Republic but also in the whole Europe. Both alder and hazel pollen cross-react with birch pollen, and the allergenicity of the two species is moderate to high.The data on temporal and spatial variability in phenophases selected with respect to their allergenic effect (flower buttons visible, beginning and end of flowering) and compiled with using statistical and GIS methods during the period 1992-2007 were compared with the current year's outcomes of the Czech Hydrometeorologieal Institute phenological network. The resulting maps use a horizontal resolution of 500 meters, method Clidata - DEM, with dependence on altitude. Temporal variability was monitored in the phenological stations Lednice (48°48' N, 16°48' E, mean above sea level (MASL) 165 m) and Horni Rokytnice (50°11' N, 16°30' E, 743 m MASL), the spatial variability in 34 stations withMASL ranging from 155 m (Doksany - Polabská nížina) to 830 m (Měděnec - Krušné hory Mts). The results are presented in tables and maps. In this case study we observed the following shifts in phenophases (lowland in comparison with mountain): flower buttons visible (38.4 days), beginning of flowering 10% (21.8 days), and end of flowering (26.3 days). The results of average entrance ofphenophase from this case study: flower buttons visible (Hazel - February 3 to February 22, Alder - February 7 to February 26), beginning of flowering 10% (Hazel - February 19 to March 20, Alder - February 22 to April 2 ), end of flowering (Hazel - March 9 to April 17, Alder - March 15 to May 13).