Phytogeographic support tor the theory of Pleistocene forest refuges in the Amazon Basin, based on evidence from distribution patterns in Caryocaraceae, Chrysobalanaceae, Dichapetalaceae and Lecythidaceae

Abstract

In recent years it has generally been accepted that Amazonia was subject to long dry periods in the late Pleistocene and post-Pleistocene which induced forest cover to a few limited areas or refuges. It has been proposed that the subsequent genetic isolation into separate populations is a mnjor factor in the evolution of the species diversity within the lowland forest of Amazonia. Most of the previous evidence for this theory is based on studies of animals, for examplelizards, butterflies, and birds. Here data are presented to confirm the theory of forest refuges using evidence from phytogeography. Distribution patterns of the lowland species of the woody plant families Caryocaraceae, Chrysobalanaceae, Dichapetalaceae and Lecythidaceae are discussed and concur with the possibility of forest refuges. A map is given of the refuge areas that seem most likely, based on evidence from species distribution of the above plant families. The refuges proposed here correspond closely with the refuge areas proposed by Haffer and Brown rather than the extremely reduced areas proposed by Vanzolini.