Status and distribution of forested wetlands in tropical South America

Abstract

Physiographically, tropical South America is characterized primarily by large watersheds (Amazon, Orinoco, Magdalena, Paraná-Paraguay, Saõ Francisco), a very long coastline, and by uplands (Andean Cordillera, highlands of Guayana and Central Brazil). Large parts of the watersheds are flat and poorly drained. Rainfall is mostly seasonal and results in sheet-flooding of thousands of square kilometres of land for several months. In addition, the great number of streams and rivers undergo a considerable fluctuation of their water levels. Extensive fringing floodplains along the water channels are exposed to numerous short and unpredictable, or to a few predictable, flood pulses. Coastal areas are also periodically flooded by the tide. Consequently most the of the wetlands in tropical South America are seasonal in nature. The total area of permanent or seasonal wetlands contributes about 20% to the total area of the region. Much of this is forested. Classification schemes of tropical wetlands and wetland forests are discussed, and the available information on the latter (distribution and extent, floristics, structure), is compiled. Human influence and conflicting areas of interest involved are also discussed.