1253 | A12 | Pollen calibration in the Catalan Pyrenees: a crucial factor to interpret its plant landscape evolution | Ramon Pérez-Obiol, Anna Badia, Marc Sánchez-Morales, Jordi Nadal
This study aims to provide a better understanding of the corelation between pollen and vegetation. There are differences in pollen productivity among different taxa that cause a non-linear relationship between pollen dispersal and vegetation data. Four elevational gradients in the Catalan Pyrenees, ranging from alpine (2750 m) to montane-basal environments (797 m), were studied. A detailed map of vegetation cover was used, and a reclassification into eight taxonomic categories that represent at least 80% of the pollen spectra was made. For each point, a moss sample (used as a pollen trap) was collected, and the percentage of vegetation cover was measured at different radii. Additionally, a detailed plant inventory was made a few meters around each point.
The pollen results showed a complete dominance of Pinus percentages, making it difficult to perceive the dynamics of other relevant taxa. In alpine environments, Poaceae is always clearly underrepresented due to the long transport of Pinus pollen. Moreover, grazing often leaves no time for plants to flower, and some species of Poaceae show changes between sexual and vegetative reproduction in response to herbivory. Additionally, there are groups within this family where cleistogamy is quite common, causing low pollen dispersion. The pollen percentages of Abies alba are highly underrepresented. It appears that a significant portion of its pollen grains settle within less than 100 meters from the sampling point. Due to the size, shape, and density of fir pollens, the decline in pollen deposition with distance from the source is remarkable. Subsequently, it can be stated that the records in the Catalan Pyrenees with high percentages of fir pollen found during the middle Holocene would indicate the presence of dense and mature fir forests nearby the coring point. Betula and Corylus populations present more unpredictable pollen percentages, probably because they act as secondary communities.
Ramon Pérez-Obiol1, Anna Badia2, Marc Sánchez-Morales3, Jordi Nadal2
1 Department of Animal Biology, Plant Biology and Ecology, Universitat Autònoma de Barcelona, Spain
2 Department of Geography, Universitat Autònoma de Barcelona, Spain
3 Department of Biosciences, Universitat de Vic-Universitat Central de Catalunya, Vic, Barcelona, 08500, Spain
ID Abstract: A12