COS 279-2 - Ecological legacies during the pre- and post-Colonial era in Amazonian forests

Abstract: Recent evidence suggests that the indigenous people in Amazonia used fire, modified soils, and directly altered plant abundances; leaving a legacy on Amazonian vegetation that persists in modern forests. The post-Columbian era, including the time of European colonization (beginning around AD 1600) and the Amazonian Rubber Boom (c. AD 1850-1920), has been largely omitted from discussions about the legacy effects of past human influences on the forest. The changes in population structure, social structure, and land use during this period likely resulted in different ecological trajectories compared with those left by pre-Columbian people. We generated predictive geographic models of the spatial distribution of pre- and post-Columbian occupation probabilities. The models showed that settlements during both time periods were likely concentrated primarily along rivers and in many instances post-Columbian occupation overlapped with that of pre-Columbian people.



Our results suggest that post-colonial human activities likely left an imprint on modern forests that in many cases may be stronger one than pre-Columbian influences. Land use intensification occurred after the arrival of European colonists who possessed new technologies including machinery and metal tools. The construction of Jesuit villages required extensive deforestation and forest burning to create space for plazas, houses, churches, and other buildings. Cacao harvesting and plantations during the Jesuit period may have favored an increase of Theobroma cacao trees in Amazonia, which may persist in today’s forests as individuals of this species can live up to 200 years. The Rubber Boom likely led to significant deforestation that remained unparalleled until the end of the twentieth century. Forests were cleared for cities and residential areas, and large amounts of timber were needed to fuel the steamers that were transporting people and produce all over the Amazon and throughout the globe. In many places these effects are likely to have overwritten pre-Columbian legacies, and reflect in today’s forests.