We are seeking to recruit a Neotropical palaeoecologist to join the recently funded “The past peoples of Amazonia: Assessing ecological legacies” project(PIDr. Crystal McMichael, funding NWO, based within the Department of Ecosystem & Landscape Dynamics). The project aims to reconstruct cultural histories from lake sediments in northwestern Amazonia, and link past human activities with modern ecological observations. The project involves analyzing microfossils (including pollen, phytoliths, and charcoal), and the development of a transfer function that estimates past human impacts in tropical forest systems.
We are particularly looking for a candidate with expertise and experience, in:
Fieldwork in remote areas.
Quantitative analysis, including familiarity with R and Geographical Information Systems.
McMichael, C.H., Feeley, K.J., Dick, C.W., Piperno, D.R. & Bush, M.B. (2017) Comment on “Persistent effects of pre-Columbian plant domestication on Amazonian forest composition”. Science 358. DOI: 10.1126/science.aan8347
Junqueira, A.B., Levis, C., Bongers, F., Peña-Claros, M., Clement, C.R., Costa, F. & ter Steege, H. (2017) Response to Comment on “Persistent effects of pre-Columbian plant domestication on Amazonian forest composition”. Science 358. DOI: 10.1126/science.aan8837
Title: Environmental change in the Yaque river area, northwestern Dominican Republic: Human impact before and after Columbus’ arrival in the New World
Date: Wednesday 26 October, 11:00-12:00
Location: Science Park 904 (please contact Henry Hooghiemstra for details if you want to attend)
Abstract: Multiproxy analysis of the 225-cm long sediment core Los Indios from the Yaque river valley in northwestern Dominican Republic (Hispaniola) shows environmental changes during the last 1150 cal yr BP. The observed changes show a period of little human distubance, followed by increasing human activity and a rapid intensification of these changes after Columbus’ arrival in AD 1492. The fastest changes on the landscape can be observed at 307 cal yr BP, when agricultural development in the Dominican Republic intensified.
Flantua, S.G.A., Hooghiemstra, H., Vuille, M., Behling, H., Carson, J.F., Gosling, W.D., Hoyos, I., Ledru, M.P., Montoya, E., Mayle, F., Maldonado, A., Rull, V., Tonello, M.S., Whitney, B.S. & Gonzalez-Arango, C. (2016) Climate variability and human impact in South America during the last 2000 years: Synthesis and perspectives from pollen records. Climate of the Past 12, 483-523. doi: 10.5194/cp-12-483-2016
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.