To detect significant quantitative changes within the palynomorph spectra, the percentage values of individual taxa or 'variables' were assigned to frequency classes to minimize the effect of minor fluctuations. These are probably due to regular variation in pollen precipitation and therefore do not reflect true changes in the frequency of the parent plants within the vegetation. Nevertheless, at the same time significant changes in the palynomorph spectra are preserved or even emphasized. Following Gauch (1982), 8 frequency classes - 0: 0%; 1: <0.5%; 2: <1%; 3: <2%; 4: <4%; 5: <8%; 6: <16%; 7: 32% - were defined for the palynomorph percentages.