ORIGINAL PAPER Long-range transport of beech (Fagus sylvatica L.) pollen to Catalonia (north-eastern Spain) J. Belmonte & M. Alarcón & A. Avila & E. Scialabba & D. Pino Received: 17 January 2008 / Revised: 25 March 2008 / Accepted: 26 March 2008 / Published online: 22 May 2008 # ISB 2008 Abstract Local and long-range transport of beech (Fagus sylvatica) pollen was analysed by using 23-year data (1983–2007) at six stations in Catalonia, Spain, and numerical simulations. Back trajectories and synoptic meteorology indicated a consistent north European prove- nance during beech pollen peak days. Specifically, the area from northern Italy to central Germany was the most probable source, as indicated by a source-receptor model based on back trajectories. For the event with the highest pollen levels (17 May 2004), back trajectories indicated a source in the Vosges (NE France) and the Schwarzwald (SW Germany) regions. By applying a mesoscale model (MM5) to this event, pollen transport could be further refined, allowing its entrance to Catalonia through the lower easternmost pass of the Pyrenees (the Alberes pass, 500 m a.s.l.) to be described. Hourly counts of Fagus pollen allowed the timing of pollen arrival during this episode to be matched with the model results regarding the above-mentioned passage. This study may help to interpret some results of modern beech genetic diversity and contribute to the understanding of paleopalynological records by taking long-range transport into consideration. Keywords Pollen . Back trajectories . Source receptor model . Mesoscale transport model Introduction Small-sized biological material, such as microorganisms, fungal spores, plant diaspores (pollen) and small seeds can be suspended in the atmosphere and transported with the wind. In some circumstances, large pulses are injected into the atmosphere, from where they can be dispersed for hundreds of kilometres (Kellogg and Griffin 2006). There is increasing interest in the entrainment and transport of such biological material to distant places because of its important consequences for (1) the transport of pathogens, (2) the expansion of the biogeographical ranges of different organisms, and (3) health effects due to the dispersion of allergenic pollen. For most plant species, pollen plays an important role in shaping the genetic structure of populations (Burczyk et al. 2004), being responsible for gene flow (Ellstrand 1992; Ennos 1994), and contributing to the spatial distribution of the species (Ellstrand 1992; Schmidt-Lebuhn et al. 2007; Sharma and Kanduri 2007; Smouse et al. 2001). The study of gene dispersal by pollen has important implications for plant biogeography and plant conservation biology. There- fore, a proper understanding of pollen dispersal is important for the management and conservation of plant species in increasingly fragmented landscapes. Specifically, pollen Int J Biometeorol (2008) 52:675–687 DOI 10.1007/s00484-008-0160-9 J. Belmonte : E. Scialabba Unitat de Botànica and ICTA, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain M. Alarcón Deptartament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Av. Víctor Balaguer, s/n. 08800, Vilanova i La Geltrú, Spain D. Pino Deptartament de Física Aplicada, Universitat Politècnica de Catalunya, Av. Canal Olímpic, s/n. 08860, Casltelldefels, Spain A. Avila (*) CREAF, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain e-mail: anna.avila@uab.es