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Summary In order to obtain a better insight into past vegetational and climatic changes along the Pole-Equator-Pole: Americas (PEP 1) transect, 32 late Quaternary pollen records from savanna and forest-savanna transition regions of the South American neotropics, north and south of the equator, have been compared. During pre-full glacial times, environmental changes in savannas were spatially complex. Some records show either stable grassland where forest exists today or a repeated alternation between forest and savanna. During the full glacial period, neotropical savannas, both north and south of the equator, expanded due to markedly drier conditions. The Amazon rain forest area must have been reduced during this period. In the southern neotropical regions, savanna area was reduced and replaced by subtropical grassland by cold climatic conditions during glacial periods. During the late glacial period, climate changed to wetter conditions north of the equator at 11,500 14C B.P. (or later) and south of the equator earlier at ca. 16,000-14,000 14C B.P. in montane regions. Wetter conditions were not recorded in the high plains or lowlands. During the early Holocene (until ca. 6000-5000 14C B.P.), the climate was drier in most of the South American savannas than during the late glacial and late Holocene. Early Holocene distribution of savanna was much larger than during the late Holocene. The general synchrony of paleoenvironmental changes since the full glacial period, from neotropical savanna sites north and south of the equator, suggests that changes in the latitudinal migration of the Intertropical Convergence Zone (ITCZ) may have played an important role. The movement of the high-pressure cell over the South Atlantic and changes in frequency of the tracks of the Antarctic cold fronts were also important.