Palaeoecology of the neotropics: an overview of the state of affairs

Resumo

An overview is given of the most important data on the palaeoecology of the Neotropics, with special emphasis on the Quaternary. Strong changes of temperature and rainfall affected tropical South (and Middle) America during the last few million of years. These changes are known in more detail from the last glacial-interglacial cycle. Relatively humid and cooler climates occurred in the period between >;50,000 and ca.25,000/30,000 years B.P.A cold and very dry climate occurred in the period of ca.21,000-c.14,000 B.P. Between 13,000 and 10.000 B.P. the climate became warmer and more humid, and from 10,000 B.P. to the present (the Holocene), the climate is more like the present, but there are still changes of temperature and especially of rainfall. While quantitative data of changes of temperature could be established beyond reasonable doubt in the high tropical Andes (6ºC-9ºC), ciphers for the tropical lowland are still uncertain (they might have been 2º to 6º lower than today). There is no doubt that the rainforest disappeared and was replaced by savanna or semidesert in some areas during certain climatic intervals. This was relatively well established on several sites in the southern part of the Amazon basin, in Bolivia and Brazil. In the northern savanna area of South America, large areas were changed in sand deserts.