Occurrence of pollen and spores in relation to present-day vegetation in a Dutch heathland area

Pollen, spores and fungal remains in moss cushions along a transect, traversing a Betula-Quercus forest and a surrounding heathland, were analysed in order to study the relation between present-day vegetation and recent pollen deposition. Pollen and spores are divided into local types from plant species encountered along the transect and regional types, not present along the transect. Relative percentages and absolute concentration of the palynomorphs were estimated. Radiocaesium activity in the moss was measured to assess the minimal duration of palynomorph accumulation (i.e. the age of the moss samples). The absence of simultaneous trends in the regional pollen types indicates that the samples do not have major differences in age. The moss represents the later stages in the heath mosaic cycle. This is supported by the radiocaesium content of the moss. Thus, in this case the concentration values of regional pollen approach deposition values. The values of the local pollen types calculated on such a rather constant regional pollen flux is considered to represent real differences in the local deposition. The local pollen types can be arranged topographically into five groups characteristic of the local vegetation types and their ecotones. The arrangement of the curves of types from phyco-, zoo-, and myco-coenoses suggests their possible origin, either locally from the heath area or from the Betula-Quercus forest, or regionally from elsewhere. Analyses and topographical arrangement of the curves of unknown types contribute in this way to their identification and their possible source of origin.