A pollen-based quantitative reconstruction of the Holocene vegetation updates a perspective on the natural vegetation in the Czech Republic and Slovakia
Abstrakt
The primary aim of this paper is to provide a pollen-based quantitative reconstruction of Holocene vegetation in order to update a perspective on natural vegetation in the Czech Republic and Slovakia. As a secondary aim we compare composition of this reconstructed Holocene vegetation with the composition of potential natural vegetation (PNV sensu Neuhäuslová et al. 1998) in the area studied.
Based on 87 individual pollen sequences, we estimate the changes in Holocene vegetation that have occurred in nine circular regions, each 60km in radius.We obtained estimates of regional vegetation using the REVEALS model (Regional Estimates of VEgetation Abundance from Large Sites). This model considers pollen productivity, dispersal and taphonomic differences between taxa.
The development of post-glacial vegetation can be divided into three general phases: Early, Middle and Late Holocene. Clustering of the interregional variability clearly separated lowlands from middle altitudes and mountains.
The Early Holocene was dominated by semi-open pine forest in nearly all the regions studied. Mixed oak woodlands appeared in the Middle Holocene and only in the lowlands, while the rest of the area studied was dominated by spruce (> 32%) forest.
The percentage of spruce remained high (> 19%) in fir-beech forests of the Late Holocene. The dominance and co-dominance of spruce at middle and high altitudes during the Middle and Late Holocene differs most from previous interpretations of pollen percentages.
We attribute this to the climatic and edaphic conditions differing from those in other parts of central Europe at a similar altitude. Continuous presence of Poaceae (> 9%) and pioneer trees during the entire Holocene (Pinus > 6%) indicates an important role of factors sustaining their long-term abundance, be it herbivory, fire or other kinds of disturbance, natural and/or anthropogenic.
ThePNV composition assumes a larger representation of broadleaved taxa at the expense of Picea.