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Taxon-related pollen source areas for lake basins in the southern Alps: an empirical approach

Conedera, Marco ; Tinner, Willy ; Crameri, Sara ; Torriani, Damiano ; Herold, Anne

In: Vegetation History and Archaeobotany, 2006, vol. 15, no. 4, p. 263-272

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    Titre
    • Taxon-related pollen source areas for lake basins in the southern Alps: an empirical approach
    Auteur
    • Conedera, Marco. WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Sottostazione Sud delle Alpi, 6500, Bellinzona, Switzerland
    • Tinner, Willy. Section of Palaeoecology, Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland
    • Crameri, Sara. WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Sottostazione Sud delle Alpi, 6500, Bellinzona, Switzerland
    • Torriani, Damiano. WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Sottostazione Sud delle Alpi, 6500, Bellinzona, Switzerland
    • Herold, Anne. WSL Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Vegetation History and Archaeobotany, 2006, vol. 15, no. 4, p. 263-272. Springer-Verlag
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:313353
    Summary
    The pollen/vegetation relationship in broadleaved forests dominated by Castanea sativa was analysed using an empirical approach. The pollen content of surface sediments of three lake basins of different sizes (6.3, 22.2, and 101.2ha) in Ticino (southern Switzerland) was used for a comparison with the surrounding vegetation. We surveyed the vegetation around the two small lakes, Lago di Origlio and Lago di Muzzano, and estimated the relative crown coverage of tree species. The regional vegetation outside the lake catchment (ca. >1km) was determined with the data from the first Swiss National Forest Inventory. For the third large lake, basin of Ponte Tresa, we used only this latter approach for comparison with pollen data. We compare uncorrected and corrected pollen percentages with vegetational data that were processed with distance-weighting functions. To assess the degree of correspondence between pollen and vegetation data we define a ratio pollen/vegetation, which allows a comparison at the taxon level. The best fit between total pollen load and vegetation is reached for a distance from the lake shore of ca. 300 m for Lago di Origlio (150×350m in size) and of ca. 600m for Lago di Muzzano (300×750m in size). Beside these general patterns, our analysis reveals taxon-specific pollen dispersal patterns that are in agreement with results from previous studies in northern Europe. Ratios of species with local (proximal) and long-distance (distal) pollen dispersal provide evidence that pollen dispersal mechanisms can influence the size of the taxon-related pollen source area, from small (100-400m) to large (>5km) for the same lake. The proportion of distal species increases with increasing lake size, highlighting the predominance of atmospheric pollen transport. We conclude that the large species-related differences in pollen source areas have to be taken into account when the provenance at a site is estimated and discussed