PALEOENVIRONMENTAL CHANGES FOR THE LAST 3000 CAL YEARS BP IN THE PUEYRREDÓN LAKE BASIN, SOUTHERN PATAGONIA, ARGENTINA

MARCOS, M.A; BAMONTE, F.P; ECHEVERRÍA, M.E.; G. D. SOTTILE; MANCINI, M. V.

Quaternary

MDPI

Lugar: Basel,; Año: 2022 vol. 5 p. 1 - 18

2571-550X

Patagonian shrub and ecotonal communities were sensitive to past environmentalchanges and thus may also be affected by future ones. Therefore, their paleoecological study constitutesa valuable tool to understand the way in which these plant communities respond to the forcingsresponsible for environmental variability. The aim of this paper is to reconstruct the vegetationdynamics of the Pueyrredón Lake area (47° 25’ 55” S; 72° 0.7’ 7” W) for the last 3000 cal yr BP andto contextualize these changes in a regional paleoclimatic framework. The results indicate that atthe beginning of the 2900 cal yr BP, the vegetation in the northwest of Santa Cruz, ArgentinianPatagonia, was represented by a grass-shrub steppe associated with forest–shrub steppe ecotonalelements. This information correlates with the larger-scale environmental inferences described forthe period, which indicate an increase in moisture availability due to the weakening of the westerlywinds. A marked change to arid conditions is indicated in the last 1050 cal yr BP, with the establishmentand development of different shrub steppe communities and the lack of ecotonal elements.Although vegetation was sensitive to changes in moisture conditions related to the variability of thewesterly winds, there is evidence of differences in the composition of shrub vegetation regardingthe sequences analyzed. Variations in pollen proportions of the shrub steppes in the PueyrredónLake area suggest that changes in vegetation are not only due to climate variability but also localfactors in the areas where shrub communities grow. The integration of the information with otherPatagonian sequences allowed to frame these changes in a regional context. The results obtainedprovide useful information to understand the way vegetation changed in the past and the mannerin which it may respond to future changes.