Human Contribution to Amazonian Plant Diversity: Legacy of Pre-Columbian Land Use in Modern Plant Communities

Amazonia is the world’s largest tropical forest and is globally important in terms of its ecosystem services and extraordinarily high levels of biodiversity. The origin of this biodiversity has long been attributed to purely natural drivers, with little consideration given to the legacy of millennia of human land use. Here, the potential contribution of pre-Columbian human activity (prior 1492 CE) to current patterns of plant diversity in Amazonia is explored via long-term (palaeoecology, archaeology) and short-term (botany, plant ecology) studies. The aim of the chapter is to examine the information available to date, and discuss recent advances and persisting shortcomings relevant to the extent to which pre-Columbian human societies influenced patterns of Amazonian plant diversity. This topic has been the subject of long-standing scientific debate over several decades, and among diverse disciplines. In recent years, this debate has intensified following the development of new techniques and data. The findings indicate that humans have had an impact upon Amazonian plant diversity for over 13,000 years. Late Pleistocene/early Holocene humans domesticated numerous plant species and may have inadvertently caused long-lasting ecosystem changes by contributing to Pleistocene megafauna extinction. Based on our literature review, we identify four key types of pre-Columbian anthropogenic impact, leaving a clear legacy upon current patterns of plant diversity: (1) construction of vast earthworks, which has altered forest and savannah cover through changes in micro-topography, fire use and hydrology, (2) widespread distribution and dispersal of domesticated plants, (3) the creation of exceptionally fertile, anthropogenic soils, which enabled continuous, intensive agro-forestry, and (4) the enrichment of plant communities with edible and useful species. We argue that knowledge of the degree to which humans have shaped plant diversity over the past several millennia has relevance for developing sustainable land use and improving our understanding of the likely responses of Amazonian ecosystems to environmental and anthropogenic disturbance.