Heijink PhD thesis 2024

April 19, 2024
WDG

Heijink, B.M. (2024) Assessing past fire regimes and their effects on modern vegetation in Amazonian forests. PhD Thesis, University of Amsterdam, Amsterdam. ISBN: 9789493260283

Abstract

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.

Handel: http://hdl.handle.net/11245.1/c1d12124-0025-44a3-90b9-c5835d9d3c5b

Mapping Ancient Africa: Video of seminar 16

April 15, 2024
WDG

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.

Details of this seminar can be found here. You can find more Mapping Ancient Africa seminar videos on the “Ecology of the Past” YouTube channel.

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Teunissen van Manen PhD thesis 2020

April 11, 2024
WDG

Teunissen van Manen, M.L. (2020) Plant wax n-alkane biomarkers in the tropical Andes (Ecuador). PhD Thesis, University of Amsterdam, Amsterdam. ISBN: 9789491407857

Abstract

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.

Handel: http://hdl.handle.net/11245.1/716e0c42-7bc7-4270-9d76-e4c556c51e1a

Cuesta PhD thesis 2019

April 9, 2024
WDG

Cuesta C., F.X. (2019) Global environmental changes in the high tropical Andes. PhD Thesis, University of Amsterdam, Amsterdam. ISBN: 9789491407758

Abstract

The high tropical Andes harbours vital ecosystems that sustain biodiversity, carbon storage, and environmental service provision for millions of people. They are identified as one of the most vulnerable terrestrial ecosystems to global environmental changes, particularly to climate change and land use conversion. Despite their vulnerability and the importance of global biodiversity conservation and Andean societies, they are among the least studied ecosystems in the world. In this thesis, I studied the patterns of summit plant community’s across the tropical section of the Andes. Further, I studied what environmental factors influence plant community composition, species diversity, and thermal niche traits in high tropical alpine ecosystems. Based on the thermal niche traits, I assessed the potential vulnerability of species and communities to climate warming, considering the effect of the climate variability hypothesis on the species niche breadths. Further, I synthesised the current state of knowledge and assessed the current and projected landscape changes in the high Andes due to the combined effect of glacier retreat and climate warming. I reviewed documented glacier changes and landscape evolution over past decades to millennia and assessed projected future glacier shrinkage until 2100 for two case studies in the Andes of Ecuador and Peru. I also evaluated the capacity of high Andean ecosystems to recover from land use changes using the aptitude to store and take up carbon together with plant diversity. Lastly, I carried out an applied research analysis aimed at informing conservation policy formulation in continental Ecuador through defining critical areas for biodiversity conservation.

Handel: http://hdl.handle.net/11245.1/c97e30b0-90d7-4363-9d33-50d288089712

Mapping Ancient Africa: Seminar 16

April 2, 2024
WDG

The next Mapping Ancient Africa seminar will take place online at 17:00 CEST on 12 April 2024.

  • Speaker: Stéphanie Bodin (Senckenberg Research Institute and Natural History Museum Frankfurt)
  • Title: Hunter-gatherers and Afromontane vegetation in the Ethiopian highlands since the end of the African Humid Period
  • Related publication:
    • Bodin, S.C., Neumann, K., Hensel, E.A., Vogelsang, R., Demissew, S., Casas-Gallego, M. & Hahn, K. (2024) Afromontane forests and human impact after the African Humid Period: wood charcoal from the Sodicho rock shelter, SW Ethiopian highlands. Vegetation History and Archaeobotany. DOI: 10.1007/s00334-023-00977-3
    • Casas-Gallego, M., Hahn, K., Neumann, K., Demissew, S., Schmidt, M., Bodin, S.C. & Bruch, A.A. (2023) Cooling-induced expansions of Afromontane forests in the Horn of Africa since the Last Glacial Maximum. Scientific Reports 13, 10323. DOI: 10.1038/s41598-023-37135-8

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 (William Gosling). 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.

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INQUA Fellowship Award: Alfred Houngnon

December 20, 2023
WDG

I am delighted to be able to report that Alfred Houngnon (University of Abomey-Calavi, Benin) has beenawarded an INQUA Fellowship for 2024 to develop his research into past environmental change in the Dahomey Gap. This research will link up my laboratory, at the Institute of Biodiversity & Ecosystem Dynamics (University of Amsterdam), and the group of Dr Mireille S.S. Toyi (Laboratory of Applied Ecology, University of Abomey-Calavi). Below, and in the associated video report, Alfred explains the project and what he hopes to achieve during the project.

The Dahomey Gap project is designed to gain new insights on the West African palaeoenvironments using pollen, charcoal and dung fungal spore records to reconstruct past vegetation, fire and animal abundances. These empirical data will then be compared against paleoclimate models. Specifically, we will explore the interactions between fire, animals and vegetation around the Ewe-Adakplame forest in the south east of Benin Republic and highlight the role humans would have previously played in the modification of the landscape for millennia.

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Palaeoecology course 2023

September 6, 2023
WDG

The pollen and phytolith identification quiz! Is that an Asteraceae phytolith I see…???

The University of Amsterdam “Palaeoecology” course commenced this week with lectures getting students up to speed with the fundamental principles and approaches to the subject, and laboratory practicals training students in the identification of micro- and macro-fossils. Once students have gained a basic understanding of pollen and phytolith identification – and demonstrated this by passing the ‘dreaded’ identification quiz – it is time to commence the group project work.

This year the students are trying to identify from which study site their ‘mystery slides’ come from on the basis of the micro-fossil assemblages (pollen and phytoliths) that they contain. The study sites all come from the area around Hilversum (Netherlands) and (could) include: heathland, pine forest, mix-deciduous forest, and birch woodlands. In addition, just to make it more interesting, one group has samples taken from the medieval palaeosol that is found locally.

Next week is field work week and the students will then need to parameterise the vegetation around the Hilversum area in such a way that they: (i) get a representative sample the variation across the landscape, and (ii) can compare the vegetation data with their micro-fossil data. Then, following the number crunching in the third week of the course, we will find out if the different groups can identify the correct study site from which there samples came…

The Palaeoecology course at the University of Amsterdam is part of the BSc Biology program, it is also frequently taken by students on the BSc Future Planet Studies degree. We also welcome students from other programs, such as BSc Béta-Gamma, and international exchange students.

The use of micro infrared spectroscopy in reconstructing past ecological and environmental change

August 16, 2023
WDG

Gosling, W.D. & McMichael, C.N.H. (2023) The use of micro infrared spectroscopy in reconstructing past ecological and environmental change. Reference Module in Earth Systems and Environmental Sciences (ed. by R. Bradshaw) Elsevier. DOI: 10.1016/B978-0-323-99931-1.00087-8

Phytolith assemblages reflect variability in human land use and the modern environment

June 29, 2023
WDG

Vegetation History & Archaeobotany

Open access:

Witteveen NH, White C, Sanchez Martinez BA, Booij R, Philip A, Gosling WD, Bush MB, McMichael CNH. 2023. Phytolith assemblages reflect variability in human land use and the modern environment. Vegetation History and Archaeobotany. DOI: 10.1007/s00334-023-00932-2

Influences of sea level changes and volcanic eruptions on Holocene vegetation in Tonga

June 8, 2023
WDG

Open access:

Strandberg, N.A., Edwards, M., Ellison, J.C., Steinbauer, M.J., Walentowitz, A., Fall, P.L., Sear, D., Langdon, P., Cronin, S., Castilla-Beltrán, A., Croudace, I.W., Prebble, M., Gosling, W.D. & Nogué, S. (2023) Influences of sea level changes and volcanic eruptions on Holocene vegetation in Tonga. Biotropica. DOI: 10.1111/btp.13231

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