Towards an ecological classification of flooded savannas in Beni (Bolivia)

Abstract

Abstract Two main types of flooded savannas are identified in Beni, one of the most extensive areas of flooded savannas in the Neotropics: the floodable savannas of the bajíos and the floodable savannas of the semi-uplands. Independent classification methods done for both floristic inventories and soil sampling show a strong relationship between the content and availability of exchangeable bases in the soils and floristic composition of the plant communities. The grassy savannas on mesotrophic substrates which are rich particularly in Mg and Ca are characterized floristically by Thevetia amazónica and Acroceras zizanioides. On base—poor substrates, the floodable grassy savannas, as well as the tajibo savanna, are best represented floristically by Andropogon bicornis and Coelorachis aurita. A CCA carried out on this type of savannas revealed a primary distribution pattern of the plant communities along an Fe gradient, which can also be explained as a gradient of the duration of the flooding period.