Compositae versus Gramineae in pollen analysis
DOI:
https://doi.org/10.54991/jop.1976.1029Abstract
Three grass pollen minima are shown in the pollen analysis from a fluvio-glacial terrace. Geological and palynological data suggest that the first minimum (12,600 BP) was probably due to very cold climate following deglaciation of the region. The second minimum (12,250-11,900 BP), simultaneous with tree pollen maximum, was probably due to the scarcity of grasses in the adjacent region which was mostly occupied by forest. The third minimum, occurring at the same time as the great increase of Compositae pollen is found at the uppermost level, close to the soil surface, suggesting contamination from modern pollen.
Comparison between modern and old pollen assemblages has shown that the pollen now being deposited present higher Compositae and lower Gramineae pollen frequency than in the past. Geological, palynological and archaeological evidences suggest that this reversion in the pollen dominants was caused by the intense use of the land, specially by the introduction of cattle in the last 400 years. If overgrazing of the grassland can somehow increase the number of Compositae plants, a new method to detect the beginning of cattle raise may be developed.
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