South and southeast Brazilian grasslands during Late Quaternary times: a synthesis

Fourteen pollen records from the south (S) and the southeast (SE) Brazilian regions have been synthesised. Late Glacial records from S Brazilian highlands document the predominance of grassland (campos) where today Araucaria forests occur. Records from SE Brazil show that during pre- and full-glacial times modem tropical semideciduous forest and cerrado (savanna to dry forest) were mostly replaced by grassland and some subtropical gallery forest. Modem montane Araucaria forests and cloud forests in SE Brazil were mostly replaced by grassland during pre- and full-glacial times. There is evidence that the modern tropical Atlantic rainforest in S Brazil was significantly reduced and replaced by cold-adapted forest taxa or grassland during glacial, especially during full-glacial times. The synthesis indicates that grasslands dominated the S and SE Brazilian landscape during the Late Pleistocene where today different forest ecosystems exist. Grassland extended over 750 kin from S to SE Brazil from latitudes of about 28degrees/27degrees S to at least 20degrees S. These results indicate that climates in the region were markedly drier and 5-7degreesC cooler during glacial times. Antarctic cold fronts must have been much stronger and more frequent than today. Studies from S Brazil show that huge areas of Late Pleistocene campos vegetation were still found on the S Brazilian highlands during early and mid Holocene times, reflecting dry climatic conditions with an annual dry period of probably 3 months. Modem wet climatic conditions with no or only short dry periods were not established until the Late Holocene period when Araucaria forests replaced large areas of grassland vegetation after about 3000 C-14 yr BY. and especially after 1500/1000 C-14 yr B.P. (C) 2002 Elsevier Science B.V. All rights reserved.