Recent research has revealed over 400 massive anthropogenic earthworks (geoglyphs), built by ancient cultures, underlying supposedly pristine ancient rainforest. These findings challenge the long-held assumption that Amazonia is a largely pristine wilderness and that indigenous peoples have only ever had a negligible impact upon Amazonian rainforest. Frank Mayle and John Carson are palaeoecologists who are collecting sediment cores from lakes located close to these geoglyphs to try and learn more about the type and scale of land use associated with these cultures. Did they make small forest clearings to build these structures or instead practice large-scale clear cutting, or maybe build them in an open landscape when past climate was too dry to support rainforest? To what extent did they alter the biodiversity of these forests by selecting economically important species over other less useful species? Analysis of fossil pollen and charcoal from these lake sediments can reveal Amazonia’s ancient history and potentially provide answers to these questions.
If you are interested in discovering more about pre-Columbian Amazonia then you may like to watch ‘Unnatural Histories: Episode 3, the Amazon. This is available on BBC iPlayer – http://www.bbc.co.uk/iplayer/episode/b0122njp/unnatural-histories-3-amazon