A stronger role for long-term moisture change than for CO2 in determining tropical woody vegetation change

May 5, 2022
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Gosling, W.D., Miller, C.S., Shanahan, T.M., Holden, P.B., Overpeck, J.T. & van Langevelde, F. (2022) A stronger role for long-term moisture change than for CO2 in determining tropical woody vegetation change. Science 376, 653-656. https://doi.org/10.1126/science.abg4618

To access this article FREE through the Science author referral service click here.

For more on the palaeoecological dataset underpinning this research check out the PhD thesis of Charlotte Miller by clicking here or here.

The origin of alkaline fen in the Mosbeek Valley in the Netherlands is due to human impact rather than a natural development

April 21, 2022
WDG

Smeenge, H., Kooijman, A., Brinkkemper, O., Mars, H.d., Mauquoy, D. & van Geel, B. (2022) The origin of alkaline fen in the Mosbeek Valley in the Netherlands is due to human impact rather than a natural development. The Holocene 09596836221088230. DOI: 10.1177/09596836221088230

Ecological baselines for the Andes

March 18, 2022
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The value of good field notes and memory really is highlighted in the publication of Grubb et al. (2020) who report the botanical findings of an expedition to high elevation (4050-4600 m) parts Ecuadorian Andes in AD 1960. The new study focuses on the relationship between vegetation and geology (lava flows), and surface processes (burning, grazing and trampling).

References

Grubb, P.J., Lloyd, J.R., Pennington, T.D. & Páez-Bimos, S. (2020) A historical baseline study of the páramo of Antisana in the Ecuadorian Andes including the impacts of burning, grazing and trampling. Plant Ecology & Diversity 1-32. https://doi.org/10.1080/17550874.2020.1819464

Ludgate PhD thesis 2014

March 15, 2022
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Natalie

Ludgate, N. (2014) Organic matter preserved in cave sediments: A new environmental proxy. PhD thesis, Department of Environment, Earth & Ecosystems, The Open University.

Abstract

Exploring new terrestrial archives to investigate past climate and the resultant impact on ecosystems is key to assessing changing climate within large continents, where major records are limited. This study presents the first comprehensive geochemical investigation of clastic cave sediments, a previously under-explored field, demonstrating the effective use of caves as an environmental archive, and recovering useable records of moisture and vegetation regime within the complicated monsoonal system of South East Asia.

Clastic cave sediments were recovered from a 2.4 m deep archaeological trench covering ~24 ka to ~12 ka within Hang Trõng, Vietnam. Clay mineral, bulk carbon, pollen, terrestrial snail shells and plant-derived lipid biomarkers were analysed to provide a multi-proxy approach. No diagenetic alteration was found below 20 cm despite clay mineral and bulk carbon δ13C analysis demonstrating microbial action and weathering of surface sediments. As previously observed in cave sediments, poor preservation lead to limited pollen recovery, however δ13C values from CSIA and shell carbonate indicates C3 vegetation persisted around the cave during the last glacial maximum.

The time-series δ18O record from recovered shells shows clear fluctuations corresponding to global climatic events including the LGM and Heinrich 1. It is hypothesised that these reflect moisture availability, with heavier isotopic values indicating drier periods. Most higher plant lipid biomarkers provide evidence for a stable forest composition, however a shift in n-alkane lipid from C31 to C27 can also be linked with the Heinrich 1 event. The warm Greenland interstadial 1 event is also expressed within the record by low δ18O shell values attributed to more available moisture and higher bulk δ13C values, which indicate greater micro-organism action.

Hang Trõng’s multi-proxy record adds to a growing body of evidence demonstrating the importance of global teleconections when assessing the impact of climate change on monsoons and local vegetation. The data collected here proves clastic cave sediments can hold valuable climatic proxies; something which is of especial importance as palaeoenvironmental archives rely on limited capture and preservation for long term environmental records.

Supervisors: Dr. Alison Blyth (The Open University/Curtin University), Dr. William D. Gosling , and Dr. Iain Gilmore (both The Open University)

Examined by: Prof. Frank McDermot (University College Dublin), and Dr. Victoria Pearson (The Open University).

To borrow a copy from The Open University Library click here.

DOI: https://doi.org/10.21954/ou.ro.0000ef12

Footnote: This post was somewhat lost (since March 2014…) and has just come to light in my blog post clean up (March 2022!). Natalie is now Laboratories Managers at Queen Mary, University of London.

Why palm fossils are important for the Amazon rainforest

March 14, 2022
ninahylkjewitteveen

With all the horror chaos in the world, science doesn’t seem like the most important thing. I forgot all about my paper, until I received an email, that… the first chapter of my PhD is published! Some positive news I would like to share with you.  

If you think about a stereotypical scientist, hidden in a lab, investigating every detail of a tiny thing…. that is great description of what I was doing! 

A snapshot of data analysis
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Legacies of Indigenous land use and cultural burning in the Bolivian Amazon rainforest ecotone

March 10, 2022
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Maezumi, S.Y., Elliott, S., Robinson, M., Betancourt, C.J., Gregorio de Souza, J., Alves, D., Grosvenor, M., Hilbert, L., Urrego, D.H., Gosling, W.D. & Iriarte, J. (2022) Legacies of Indigenous land use and cultural burning in the Bolivian Amazon rainforest ecotone. Philosophical Transactions of the Royal Society B: Biological Sciences 377, 20200499. https://doi.org/10.1098/rstb.2020.0499

Early to mid-Holocene human activity exerted gradual influences on Amazonian forest vegetation

March 9, 2022
WDG

Nascimento, M.N., Heijink, B.M., Bush, M.B., Gosling, W.D. & McMichael, C.N.H. (2022) Early to mid-Holocene human activity exerted gradual influences on Amazonian forest vegetation. Philosophical Transactions of the Royal Society B: Biological Sciences 377, 20200498. https://doi.org/10.1098/rstb.2020.0498

A palaeoecological perspective on the transformation of the tropical Andes by early human activity

March 8, 2022
WDG

Bush, M.B., Rozas-Davila, A., Raczka, M., Nascimento, M., Valencia, B., Sales, R.K., McMichael, C.N.H. & Gosling, W.D. (2022) A palaeoecological perspective on the transformation of the tropical Andes by early human activity. Philosophical Transactions of the Royal Society B: Biological Sciences 377, 20200497. https://doi.org/10.1098/rstb.2020.0497

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