Eastern Andean environmental and climate synthesis for the last 1500 years BP from terrestrial pollen and charcoal records of Patagonia

SOTTILE, G.D.; MANCINI, M. V.; MARCOS, ALEJANDRA; BAMONTE, FLORENCIA; ECHEVERRÍA, MARCOS

Medellín

Simposio; LOTRED-SA 3rd International Symposium. Climate change and human impact in Central and South America over the last 2000 years. Observations and Models; 2014

PAGES

Since the last 10 years there have been major improvements on the interpretation of terrestrial pollen and charcoal records from the Eastern side of the Patagonian Andes. New evidence from past paleoenvironmental changes have been recorded with accurate chronological control from lakes and peat-bogs of forest and steppe communities between 36°S and 52° S. Vegetation patterns in Patagonia respond mainly to the west-east precipitation gradient at a regional scale. Meanwhile at a local scale, understanding individual species responses to local humidity patterns is extremely useful to improve the reconstruction of past vegetation dynamics related to past climate variability. Also, the comparison between current fire behavior through different Patagonian communities and past charcoal records would improve paleoclimate variability inferences during the last 1500 years. During this study paleovegetation/water balance indexes were performed at 7 sequences of pollen records from forest and steppe communities at the eastern side of the Patagonian Andes. Paleo-indexes patterns were compared to other Patagonian lake and peat-bog sequences, including pollen and charcoal records published recently. Between 1500 and ca. 800 cal yrs BP, paleovegetation indices and charcoal records suggest dense humid forest communities south to 45° S. The opposite signal is recorded in northern forest communities, suggesting open forest communities and high fire activity. Meanwhile steppe environments show low vegetation cover and low fire activity probably linked to xeric conditions.