Ocorrência de Kielmeyera nos "campos de Humaitá" e a natureza dos "campos" Flora da Amazônia

Kubitski, Klaus

Summary Several authors have repeatedly emphasized the floristic and physiognomic similarity between the Amazonian "campos" which are savanna islands surrounded by high forest, and the cerrado vegetation of Central Brazil. Consequently, it was suggested that these savanna islands be the remnants of a former epoch when a cerrado type vegetation extended over large parts of tropical America. It is shown, however, that those tree species of the cerrado flora which are characterized by heavy, gravity-dispersed diaspores, as for instance Caryocar brasiliense, are absent from the "campos". On the other hand, a high proportion of the "campos" elements is provided with lightweight, alate diaspores edapted for dispersal by wind; other members of this vegetation show adaptations for dispersal by birds, bats or other vertebrates. In the prominence of adaptation for dispersal over greater distances there is a similarity between the "campos" and the Central Amazonian "campinas"; the difference, however, lies in the strong emphasis on ornithochory in the "campinas". It is concluded that during some phases of the Pleistocene it was not the cerrado vegetation itself but a generalized neotropical savanna type vegetation which replaced the rain forest In some areas and possibly allowed for an exchange of savanna species from the north to the south and/or vice versa through the Amazonian basin.