The fifth Mapping Ancient African project took place on Monday 11 April 2022 and focused on the African Pollen Database and past vegetation change in Africa.
The seminar was delivered by Sarah Ivory (Penn State University), Rahab Kinyanjui (National Museums of Kenya), and Lynne Quick (Nelson Mandela University). The seminar covers the principles behind and the working of the African Pollen Database (why make data openly available?) and the latest advances in eastern and southern Africa.
For more about the African Pollen Database check out:
I am delighted to announce the publication of the new volume in the Palaeoecology of Africa series. I had the privilege to guest edit this with Anne-Marie Lézine and Louis Scott. The final version is now available OPEN ACCESS online.
Gosling, W.D., Lézine, A.-M. & Scott, L., eds. (2021) Quaternary Vegetation Dynamics: The African Pollen Database. Series editor: Runge, J. Palaeoecology of Africa: Volume 35. CRC Press. ISBN: 9780367755089 DOI: 10.1201/9781003162766
Huisman, S.N.*, Bush, M.B. & McMichael, C.N.H. (2019) Four centuries of vegetation change in the mid-elevation Andean forests of Ecuador. Vegetation History and Archaeobotany. DOI: 10.1007/s00334-019-00715-8
Valencia Castillo, B.G. (2014) From glacial to modern conditions: Vegetation and climate change under human influence in the Central Andes. PhD Thesis, Department of Environment, Earth & Ecosystems, The Open University.
Conservation, restoration and management strategies are employed to maintain Earth’s biological diversity and physical environment to a near “natural” state. However, the concept of “natural” is generally inexact and may include degraded landscapes. In absence of long-term empirical data of natural baselines, impacted assemblages (human altered baselines) could be falsely assumed to be natural and set as conservation or restoration goals. Therefore, the identification of long-term ecological baselines becomes a pressing requirement especially in threatened biodiversity hotspots such as the tropical Andes that were under human pressure for several millennial.
This thesis aims to identify ecological baselines for tropical Andean ecosystems based on multi-proxy palaeoecological reconstructions from three Andean lakes. Trends of vegetation change are used to identify when landscapes became anthropogenic in the Andes. Because vegetation assemblages at c. 10 ka experienced negligible anthropogenic impacts and had modern-like climate condition, this time was considered the most recent period likely to provide insight into natural ecological baseline conditions.
Changes in vegetation assemblages were evaluated over time departing from 10 ka around Miski and Huamanmarca, two sites that remained virtually impervious to human impacts. Baselines in Miski and Huamanmarca drifted continuously over time and showed that baselines are dynamic entities. The vegetation assemblages derived from Miski and Huamanmarca suggest that that human impact was not homogeneous throughout the Andean landscape.
Once baselines were defined it was possible to evaluate if the spatial distribution of Andean woodlands represented by Polylepis was a product of human impacts. A MaxEnt model generated based on 22 modern environmental variables and 13 palaeoecological vegetation reconstructions showed that Polylepis woodlands were naturally fragmented before humans arrived in South America (14 ka). However, the influence of humans during the mid and late Holocene enhanced the patchiness of the forest generating a hyper-fragmented landscape.