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

The use of simple linear regression to data of pollen rain and vegetation c over in Patagonia (Province of Chubut, Argentina) allowed us to develop qua ntitative relationships between modem pollen rain perecentages and vegetati on cover for the taxa Poaceae, Papilionoideae, Senecio type, and Mulinum sp inosum. The analysis revealed a good fit of data to regression lines for al l 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 Poa ceae (0.66) and Papilionoideae (0.61). These regressions allowed us to infe r the presence or absence of regional pollen and predict the quantity of po llen in the absence of the vegetation producing it. In this regard, the stu died pollen rain includes the regional contribution (except Papilionoideae) , even though M. spinosum has a low contribution. This overrepresentation i s attributed to long-distance transport associated to the westerly winds. T hese quantitative relationships will allow us to know past vegetational cha nges of these taxa from fossil pollen spectra in the studied area.