Pollen- vegetation relationships of some taxa from the Patagonian steppe (Argentina)

The use of simple linear regression to data of pollen rain and vegetation cover in Patagonia (Province of Chubut, Argentina) allowed us to develop quantitative relationships between modem pollen rain perecentages and vegetation cover for the taxa Poaceae, Papilionoideae, Senecio type, and Mulinum spinosum. The analysis revealed a good fit of data to regression lines for all taxa, with high Pearson r coefficient values in the case of M. spinosum (0.82) and Senecio type (0.81), and somewhat lower values in the case of Poaceae (0.66) and Papilionoideae (0.61). These regressions allowed us to infer the presence or absence of regional pollen and predict the quantity of pollen in the absence of the vegetation producing it. In this regard, the studied pollen rain includes the regional contribution (except Papilionoideae), even though M. spinosum has a low contribution. This overrepresentation is attributed to long-distance transport associated to the westerly winds. These quantitative relationships will allow us to know past vegetational changes of these taxa from fossil pollen spectra in the studied area.