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

Wei PhD thesis 2023

April 17, 2024
WDG

Wei, C. (2023) Morphometrics of modern and fossil Poaceae pollen from South America. PhD Thesis, University of Amsterdam, Amsterdam. ISBN:

Abstract

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.

Handle: http://hdl.handle.net/11245.1/1f4f5550-1069-423a-ace3-2192ac4160c6

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

Pre-contact and post-colonial ecological legacies shape Surinamese rainforests

April 10, 2024
WDG

Open access:

Witteveen, N.H., White, C., Sánchez-Martínez, B.A., Philip, A., Boyd, F., Booij, R., Christ, R., Singh, S., Gosling, W.D., Piperno, D.R. & McMichael, C.N.H. (2024) Pre-contact and post-colonial ecological legacies shape Surinamese rainforests. Ecology, e4272. DOI: 10.1002/ecy.4272

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

PhD Scholarship program for migrants in the Netherlands

April 5, 2024
WDG

The Dutch science foundation (NWO) currently has a call for proposals to support migrants to the Netherlands to undertake a PhD project.

Applicants must have:

  • a Dutch passport (or residency status),
  • a masters level degree from a university in the Kingdom of the Netherlands, and
  • have been born in specific regions outsides the Netherlands (or be the child of someone born outside the Netherlands)

For full details click here visit the NWO Mozaiek 2.0 call web page.

If you think you might fulfill all the criteria for application, and are interested in conducting a PhD on a “ecology of the past” related theme at the University of Amsterdam, please do not hesitate to get in contact. I am then happy to check eligibility and discuss if your skill set and interests would be appropriate to apply for a PhD scholarship with us. I would be delighted if we would be able to support an applicant to this scheme.

Deadline for applications: 21 May 2024 (but please get in contact as soon as possible so that we can make the relevant eligibility checks and discuss ideas).

Contact: William D. Gosling

Mapping Ancient Africa: Quaternary International special issue

April 5, 2024
WDG

The Mapping Ancient Africa (MAA) special issue of Quaternary International (QI) will open for submission on 30 April and will close 30 July 2024. To submit your article go to the QI submission portal and click “submit new article”, you will then be asked to “select article type”. From the drop down list select “SI: Mapping Ancient Africa”. This will ensure that your manuscript is directed to the guest editorial team. Submissions should follow the standard QI guideline (click here for details) and take account of the advice for submission to this special issue (click here for details).

The special issue is centered around work and papers presented in the MAA Rome workshop and sessions at the INQUA Rome congress (session 1, session 2), however, if you have a manuscript that you think would be appropriate for inclusion given the research themes of the project please also consider submitting. If you have any questions feel free to contact the editorial team in advance.

For further information on:

Presenters in the Mapping Ancient Africa session of the INQUA Rome congress 2023
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What has biogenic silica ever done for us?

April 3, 2024
WDG

Siliceous Microfossils Meeting

  • Date: Friday 24 May 2024
  • Location: Institute for Biodiversity & Ecosystem Dynamics, University of Amsterdam

Program

  • 13:00-14:00 – Palynologische Kring society annual meeting
  • 14:00-14:15 – Coffee
  • 14:15-15:45 – Seminar series
    • Using phytolith analysis to detect palm enrichment in Amazonia Nina Witteveen (University of Amsterdam)
    • Starch grains as indicators of plant food consumption in Neanderthals and Early Modern Humans Amanda Henry (University of Leiden)
    • Paleoenvironmental history of an archaeological lagoon in Central Italy: Insights from diatom analysis Majoi Nacimiento, Teye Aukes & Jan Sevink (University of Amsterdam)
  • 15:45-17:30 – Laboratory activities
    • Advances in topical phytolith identification Nina Witteveen (University of Amsterdam)
    • Finding Suitable Grounds – combining the on/off site approach through phytolith investigation in Flevoland Ana Smuk (Rijksuniversiteit Groningen)

If you are not already a member and would like to attend please contact the society via email or the web portal: https://www.palynologischekring.nl/contact/

To find out more about the Palynologische Kring click here to visit the web site.

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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