A pollen-climate calibration from western Patagonia for palaeoclimatic reconstructions

Abstract

Palaeoecological studies of sediment records from the western margins of southern South America have revealed vegetation dynamics to be under the influence of major regional climate drivers such as the Southern Westerly Winds, Southern Annular Mode and El Nino Southern Oscillation. Despite the substantial number of ~ palynological records in this region, very few quantitative pollen-based climate reconstructions using surface samples have been made. In this context, our objective was first to investigate the modern pollen–vegetation– climate relationships in the western Patagonian. The results show that the modern pollen dataset reflects the main vegetation types and that summer precipitation and winter temperature represent the main climate parameters controlling vegetation distribution. Secondly using this pollen–climate dataset we evaluate and compare the performance of two models (Weighted Averaging Partial Least Squares and Modern Analog Technique). We used these models to make climate reconstructions from two oceanic pollen records from western Patagonia. Compared with independent climate indicators, our pollen-inferred climate reconstructions reveal the same overall trends, showing the potential of pollen–climate transfer functions applied to this region. This study provides much needed data for quantitative climate reconstructions in South America, but which also needs to be improved by enlarging the modern pollen dataset.