de Weger, L.A., Verbeek, C., Markey, E., O’Connor, D.J. & Gosling, W.D. (2024) Greater difference between airborne and flower pollen chemistry, than between pollen collected across a pollution gradient in the Netherlands. Science of The Total Environment 172963. DOI: 10.1016/j.scitotenv.2024.172963
The SASQUA congress will kick off next week (19-24 May 2024) in Cango Valley (South Africa). Sessions cover many aspects of Quaternary science and range from archaeology through palaeoclimate to geological topics. The full program is now available to download.
Quick, L.J & Asithandile, N. (2024) Proceedings of the XXIV Biennial Congress of the Southern African Society for Quaternary Research (SASQUA), Cango Valley, South Africa, 19-24 May 2024. DOI: 10.5281/zenodo.11125697
To find out more about the meeting and other SASQUA activities you can also visit the organizations web pages: https://sasqua.co.za/
The 17th online Mapping Ancient Africa seminar took place on Thursday 16 May 2024. The seminar was delivered by N’dji dit Jacques Dembele and was entitled “Evidence of recent seismicity in the West African Craton: The Bamako seisemites Mali”. In the seminar surprising new evidence for Quaternary seismic activity within the West African Craton – which was thought to be tectonically stable – was presented. Specifically, the identification of clastic dykes and deformation within sedimentary and lacustrine deposits was used to suggest past high magnitude earth quakes in the last 170,000 years.
Alfred Houngnon was awarded an INQUA Fellowship in 2024 to develop his work on past environmental change in the Dahomey Gap (western Africa). Through the project Alfred is making a series of videos about his fellowship journey. In the first video Alfred introduced his project and collaborators (click here to watch the first part). In the two latest instalments (below) Alfred explains: (i) one of his key methodological approaches (modern pollen trapping), and (ii) the modern vegetation of the region and current threats to the vegetation.
The next Mapping Ancient Africa seminar will take place online at 17:00 CEST on 16 May 2024.
Speaker: N’dji dit Jacques Dembele (President of WAQUA, Université des sciences sociales et de gestion de Bamako, Mali)
Title: Quaternary period seismicity on the West African Craton
The seminar will be delivered via Zoom. The link for the seminar can be obtained from the MAA Slack channel or by contacting the chair of this seminar (Stefanie Kaboth-Bahr). If you want to know more about the Mapping Ancient Africa project visit our web pages and please do not hesitate to get in contact if you want to get involved.
Amazonian rainforests are incredibly biodiverse and provide global ecosystem services, but are threatened by fires, which completely alter ecosystem function and structure. Fires, especially in western Amazonia, almost always have an anthropogenic origin. However, much is unknown about the long-term recovery and multi-generational successional processes following fire events. Due to the long lifespan of tropical trees, past fires may have left ecological legacies in modern forest composition in Amazonia. The goal of this thesis is to investigate how past fire events impact successional trajectories of past vegetation change and whether these fire events and related human impacts have left ecological legacies in modern Amazonian forests. I specifically focus on western Amazon and changes in palm abundances and composition through time, as palms were an economically important plant family to past peoples. I compared lake charcoal records across the Amazon Basin and found fire was least prevalent in western Amazonia. On a local scale, very limited evidence of past disturbances was present in forest plots in northwestern Amazonia. Palm abundances have been increasing since the mid-Holocene, but this increase is not related to past fire events. Past fire likely have left low to none ecological legacies in these forest plots. Modern trait composition across western Amazonia is associated with past fire events, but more research is necessary to disentangle relationships between past fire, soils, and modern vegetation. Overall, western Amazonia likely contains the least intense ecological legacies in comparison with the rest of Amazonia.
Poaceae (the grass family) is one of the most diverse angiosperm families on Earth, comprising close to 12,000 species. The history of grass-dominated biomes extends back over 20 million years, yet the spatial and temporal development of these biomes and the underlying drivers remains unresolved. This thesis addresses these questions in South America, focusing on modern grass pollen and ancient samples dating from the early Miocene to the present. The thesis reveals several key points: (i) Grass pollen size varies significantly both among genera and species and within species. Pollen size shows no correlation with (a)biotic factors, indicating its limited utility as a generally applicable proxy for reconstructing past vegetation and climate; (ii) Grass pollen exhibits high diverse on surface ornamentation. The morphotypes identified by descriptive terminology are well-supported by a combination of SEM images of pollen surface patterns and computational image analysis. The findings reveal that pollen sculpture is unrelated to (a)biotic variables but is diverse across the phylogeny; (iii) Tropical grass pollen morphology suggests a gradual rather than punctuated evolution, based on the trend toward a less dense ornamentation of the exine since c. 23 Ma. The changes in the exine of grass pollen since the early Miocene might be driven by evolutionary processes (evolutionary drift and/or directional selection), and potentially immigration at the continental scale. In summary, the thesis reveals the trajectory of grass pollen morphological changes over time and examining the drivers that have contributed to their evolution and geographical expansion at the continental scale.
The 16th Mapping Ancient Africa seminar took place online on Friday 12th April 2024. The seminar was delivered by Stéphanie Bodin (Senckenberg Research Institute and Natural History Museum Frankfurt). In the seminar Stéphanie demonstrated how the examination of ancient charcoals found in caves used for shelter by hunter-gather populations living in Ethiopia at the end of the African Humid Period (4,000-2,000 years ago) can provide insights into vegetation and human selection of woody resources.
Developing new applications for plant wax n-alkane biomarkers can deepen our understanding of ecosystem history. In this thesis I study modern and sedimentary n-alkane signals, sourced along the tropical Andes, to better understand how they can be used as a proxy for past environmental change. The overarching question addressed in this thesis is: what do n-alkane patterns extracted from sedimentary records reflect? Specifically, I address:• Do environmental or taxonomic factors dominate the n-alkane signal?• Does the n-alkane signal alter as the plant material degrades?• How much of the n-alkane variability can be explained by our analytical protocols?I find that the taxonomic and environmental signals of n-alkane patterns are entangled, especially in leaf n-alkanes. Soil n-alkane patterns reflect environmental conditions at the site, but the results cannot rule out a taxonomic signal in soil n-alkane patterns. I also find that, as the source material degrades (leaves), the n-alkane patterns are altered. Although the n-alkane signal is recognizable as having plant origin, there is a reduction in n-alkane pattern variability and the metric for degradation becomes an increasingly important descriptor of the n-alkane pattern shifts observed in soils and sediments. I find evidence that the metric for degradation can be used as proxy for past environmental change, but the application of this n-alkane signal proxy is not straightforward. Finally, I find there is little understanding of how much extraction and measurement protocols contribute to the n-alkane pattern variability and what implications this has on interpretations of the n-alkane signal.
Ecology of the past 