Periodic Reporting for period 3 - LASTJOURNEY (The End of the Journey: The Late Pleistocene-Early Holocene Colonisation of South America)
Reporting period: 2022-10-01 to 2024-03-31
A critical set of questions corresponding to three research themes remain unanswered:
1. Human mode and tempo of dispersal. When did people begin to colonise the different environments of northwest South America? How did the tempo of dispersal vary between environments? Are these adaptations correlated with major changes in material culture?
2. Changing climates and environments. What was the timing and nature of climate change during the LP-EH transition? What were the plant and animal associations that initial tropical colonists encountered and how did they change over time? When did the extinction of native megafauna happen and what was its ecological impact? How did these climate and environmental perturbations impact the human colonisation of South America?
3. Subsistence strategies and human impacts. How did these early colonists tune their subsistence strategies to the Andean forests, Sub-Andean forests, lowland tropical forests, savannahs, and coastal landscapes they confronted? When, how and which plants and animals were exploited in these different environments? Were these early colonists highly mobile, big-game hunters or territorial foragers subsisting on a wide variety of local foods? How did colonists adapt their subsistence strategies to abrupt climate events and the arrival of the wetter, warmer Holocene? When and which plants were first cultivated and domesticated? Did these foragers manage plant and animal resources by fostering environmental conditions that promoted preferred foods? What was the role of humans versus climate in the extinction of megafauna?
To investigate these sets of questions Last Journey will employ an innovative interdisciplinary research strategy combining state-of-the-art palaeoclimate, palaeoecology, archaeology, archaeobotany, ancient eDNA and isotope studies.
Initial results from the analysis of rock art and archaeological sediments from Serrania de la Lindosa have been published in three international journals and one book chapter. The findings reveal a far more extensive and earlier occupation of the Colombian Amazon than previously realised. Radiocarbon dating from the excavated contexts demonstrates multiple rock shelters were occupied from 12.5k years ago. The depiction of megafauna in the art alludes to the different habitats and animal populations that were present during these early human occupations. The artwork and archaeological remains hold clues to the inception of human-environment interaction in the Amazon, the potential role human resource exploitation had on biodiversity trajectories, and the development of cosmological worldview, cultural norms, and artistic traditions that characterise and define South American culture. Further collaborations on early peopling of tropical South America, plant domestication, and the analysis of glyptodon (Ice Age armadillos) skulls have resulted in the publication of three other papers (Nature, Quaternary Science Reviews, and Journal of Swiss Palaeontology). The project organised a major international rock art symposium in Colombia and produced the book, "The Painted Forest: rock art and archaeology in the Colombian Amazon". 400 copies of the book were donated to the local community for sale to tourists.
The discovery of far more extensive rock art than was realised in the Colombian Amazon, coupled with the identification imagery representing now extinct megafauna, and the confirmed human occupation during the Late Pleistocene, has major implications for the role of humans in shaping the vegetation and animal populations during the dramatic climatic upheaval during the Late Pleistocene to Holocene transition. Archaeobotanical analyses suggest palm were a key resource enabling low risk experimentation and adaptation to forest resources, with potential impacts on vegetation structure and composition as a result of resource exploitation. The overlap of humans and megafauna, as evidenced by the early dates of human occupation and the depiction of megafauna in rock art, including hunting scenes, suggests human predation has a role in the extinction of these animal populations, which were already stressed due to changing habitats caused by climatic change.