Last glacial maximum (LGM) vegetation changes in the Atlantic Forest, southeastern Brazil

This study was carried out in a continental Atlantic Forest located in the southern region of São Paulo State, southeastern Brazil. The aim of the study was to evaluate the vegetation dynamics in ∼70 km forest ecosystem transect that occurred during the late Pleistocene and Holocene in this region, using the stable carbon isotopes (δ13C) analysis on soil organic matter (SOM) and the 14C dating of buried charcoal fragments and the humin fraction of SOM. The isotope data (δ13C) of SOM in the deeper horizons, indicating the presence of more open vegetation than the present, with a probable mixture of C3 and C4 plants, suggesting the presence of a drier climate in the period of ∼20 ka to ∼16–14 ka BP. From ∼16 to 14 ka BP to the present, a significant predominance of C3 plants was observed, indicating an expansion of the forest, probably associated with the presence of a more humid climate than the previous period. The results indicated the presence of open vegetation during the late glacial, probably associated with a drier period, also observed in other regions of Brazil. The Atlantic Forest ecosystem seems to have developed at least since the early Holocene in southeastern Brazil.