Modern vegetation and its pollen spectra in the Cantabrian mountains, northern Iberian Peninsula, compared with fossil pollen records

Abstract

The study of the pollen rain from modern vegetation has greatly improved the interpretation of pollen diagrams and our understanding of ancient plant communities. In this study, 76 pollen samples were studied from various vegetation types in Cantabria, northern Iberian Peninsula. The pollen signals of the main taxa were compared to their estimated spatial coverage at various scales (100 m, 1 km and 5 km from the sampling point) using vegetation maps. Additionally, we investigated whether there were similar modern vegetation types to past ones interpreted from the pollen record from La Molina peatland, Cantabria. Our results revealed that the pollen rain from the laurel-evergreen oak community (Lauro nobilis-Quercetum ilicis) was mainly evergreen Quercus pollen (59-77%), with Laurus nobilis being very under-represented. The representation of Fagus sylvatica pollen varied according to its local presence. In the modern vegetation, two sample sites with over 95% cover of Fagus within a 100 m radius had a pollen content below 3%. Pine demonstrated high dispersal capability, with pollen values exceeding 20% even in samples with little or no pine cover within 1 and 5 km. Poaceae had limited representation, with up to 60% even in samples lacking tree cover within a 5 km radius. Mixed deciduous woodlands were dominated by deciduous Quercus and Corylus, and their resemblance to woods in the northern Iberian Peninsula during the mid Holocene is discussed. While a principal component analysis linked modern vegetation to the most recent part of the pollen diagram from La Molina, no clear parallels emerged between present-day and ancient vegetation. Finally, it was found that there were no differences in pollen concentrations trapped by acrocarpous and pleurocarpous mosses.