PhD: When was the South Pacific colonised?

October 19, 2017
WDG

Title: When was the South Pacific colonised? A lake sediment approach to understanding climate:human drivers of ecosystem change on remote Pacific Islands

Location: University of Soithampton (Geography & Environment)

Supervsiory team: Dr. Sandra Nogué, Prof Mary Edwards, Prof. David Sear, Dr. William Gosling (University of Amsterdam), Prof. Inger (Tromso University), Prof. Janet Wilmshurst (Landcare research and University of Auckland)

Rationale: The Pacific islands of Polynesia were among the last places on earth to be colonised by humans. The precise dates of colonisation are debated – a situation which arises from the different sources of evidence (1, 2). New lake sediment records from the Cook Islands (Atiu, Mangaia) and Samoa (Upolu) and Tonga show very clear evidence of disturbance, but what is unclear is to what extent the signal represents the arrival of humans or a change in climate (2). A key question for the analysis of sedimentary records is the ability to distinguish natural variability in the environment of Pacific Islands from that arising from the arrival of humans in a temporal and spatial context. We aim to use a multi-proxy approach based on SedDNA, lipid biomarkers, fossil charcoal, and pollen preserved in lake sediments to identify: a) the presence of humans and/or livestock that were brought with them, and b) the related environmental change. Multiproxy approaches supported by statistical analysis, will be deployed to four sites where we already have good chronological controls and high resolution records of palaeoclimate. We are well placed to apply new methods and higher resolution analyses to address fundamental questions about the response of remote pacific islands to climate and human forcings.

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PhD: Stress in Paradise

October 19, 2017
WDG

Title: Stress in Paradise: Quantifying the frequency and impacts of ENSO driven droughts in tropical Pacific Island Nations

Location: University of Soithampton (Geography & Environment)

Supervisory team: Prof. David Sear, Prof. Justin Sheffield, Prof Ian Croudace (National Oceanographic Centre, Southampton).

Rationale: Because of their small size and isolation, islands in the Pacific have limited and fragile natural resources, making them more vulnerable to climate hazards and stresses than are continents1. Pacific Island Nations (PINS) also occupy the region of the earth’s surface most immediately impacted by ENSO events. The impacts of El Nino events are felt across 3,975 islands, 13 island nations, affecting a population of 12.9 million who rely on rainfall for freshwater and food security. To date our understanding of the mechanisms of drought, their frequency and duration, and their biophysical effects in PINs remain poorly quantified. In addition island types experience droughts differently, varying according to their location, topography, geological history and ecology. Droughts are also thought to have been important drivers of the human colonization of the Pacific2. Drought frequency is likely to increase in the tropical pacific but again its specific impacts are largely unknown. This PhD seeks to develop a step change in our understanding of droughts based on novel coupling of long term data on drought frequency with process based drought modelling.

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PhD position: When was the South Pacific colonised?

October 31, 2016
WDG

Funded PhD studentship at:
Palaeoenvironmental Laboratory
Department of Geography & Environment
University of Southampton

Title: When was the South Pacific colonised? A lake sediment approach to understanding climate:human drivers of ecosystem change on remote Pacific Islands

Supervisors: Sandra Nogue, Pete Langdon, David Sear (all University of Southampton), and William Gosling (University of Amsterdam)

Deadline: 2 January 2017

To find out more about the project, check eligibility criteria, and details of how to apply click here.

The team lake coring in the South Pacific. Photo Jon Hassall, see more: https://goo.gl/viiLSQ

The team lake coring in the South Pacific. Photo Jon Hassall, see more: https://goo.gl/viiLSQ

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Biodiversity and the functioning of tropical forests

July 12, 2016
WDG

Biodiversity and the functioning of tropical forests
PhD defense University of Wageningen
Candidate: Masha T. van der Sande
Date: 06/07/2016

Watch Masha’s thesis defense on WUR TV (featuring W.D. Gosling as an opponent…)

WRUTVClick here to watch the video

Ecology of the past on film: Hayley Keen

October 6, 2015
WDG

Whilst conducting her PhD research Hayley Keen helped produced two of short films about her research project Past environmental change on the eastern Andean flank, Ecuador:

  1. on her field work, which was the winning entry into the American Geophysical Union (AGU) student video competition in 2014, and
  2. a presentation summing up her PhD project in just 3 minutes!

First prize in the AGU student video competition (2014)

Three minute thesis (The Open University, 2014)

Follow Hayley’s ongoing research on this blog and on Twitter @Hayley1keen 

Keen PhD Thesis 2015

September 30, 2015
WDG

Hayley Keen getting excited about sediments during fieldwork in Ecuador (2012). Photo: J. Malley

Hayley Keen getting excited about sediments during fieldwork in Ecuador (2012). Photo: J. Malley

Keen, H.F. (2015) Past environmental change on the eastern Andean flank, Ecuador. PhD Thesis, Department of Environment, Earth & Ecosystems, The Open University.

Abstract
The eastern Andean flank of Ecuador (EAF) contains some of the world’s most biodiverse ecosystems. Andean montane forests are threatened due to anthropogenic pressures and both current and projected climate change. This thesis examines the palaeoecological history of two stratigraphic sequences (Mera Tigre West [MTW] and Mera Tigre East [MTE]) obtained from the Ecuadorian modern lower montane forest. The sediments preserved were analysed using eight analytical techniques, allowing an insight into the ecosystem’s potential response to projected changes derived from their past responses. Palaeoecological studies on the EAF are rare, and those that do exist are debated relating to: i) the inference of robust ecological data from pollen records in floristically diverse locations, and ii) the past source area of sediments preserved in fluvially exposed sequences, potentially leading to contamination with older material.

A statistical sub-sampling tool was developed (debate i), capable of producing statistically robust count sizes for each pollen sample; MTW and MTE count sizes ranged from 196-982 showing the diversity within sequences. The depositional environment of MTE was analysed, investigating sediment provenance throughout (debate ii). Results found that large scale volcanic events were critical in the preservation of the sediments, whereas fluvial influence caused a regional sediment source area in the upper stratigraphy, impacting on the palynological interpretation of MTE. Pollen records demonstrated the presence of a diverse vegetation community with no modern analogue at MTE (abundant taxa (>15 %): Hedyosmum, Wettinia, Ilex) and upper montane forest at MTW (Alnus, Hedyosmum, Podocarpus). Fire was not the main driver for the vegetation reassortment at either site (MTW correlation coefficient: -0.37, MTE: 0.16). The two sites have demonstrated the EAF plays host to floristically dynamic ecosystems, susceptible to drivers of change (fire and landscape) and should be considered when predicting the montane forests’ future response to environmental change.

Supervisors: Dr. William D. Gosling (The Open University/University of Amsterdam), Dr. Encarni Montoya and Dr. Sarah Sherlock (both The Open University).
Examiners: Dr. Dunia Urrego (University of Exeter), and Prof. David Gowing (The Open University).
Chair: Dr. Mark Brandon (The Open University).

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

Publications (so far): Continue Reading

JOB: PhD candidate in Palaeoecology & Landscape Ecology

July 28, 2015
WDG

UvAInstitute for Biodiversity & Ecosystem Dynamics
Faculty of Science

University of Amsterdam

Characterization of Neotropical ecosystems by their modern pollen spectra and organic chemical composition

  • Develop skills in pollen identification, pollen chemical characterization, and the analysis of organic biomarkers.
  • Examine ecological variation across an altitudinal gradient of nearly 4000 meters on the tropical western Andean flank.
  • Improve understanding of how ecosystems function in a biodiversity hotspot, and how they might be identified in the fossil record.

Mashpi (25)The considerable biodiversity of Neotropical ecosystems is under pressure from projected climate change and human activity. Modern ecosystems can be characterized by their pollen rain and organic chemistry, which can in turn provide information about ecosystem health and functioning. However, little is known about how pollen assemblage and chemical composition (of pollen and plants) vary along environmental gradients. Altitudinal transects provide an opportunity to study a range of environments and ecosystems with a relatively small geographic area. By improving our understanding of modern ecosystems we can improve our interpretation of fossil records, and consequently better understand how modern ecosystems came into being.

The main objectives of this PhD project are to:

  1. Generate the first modern pollen assemblage and chemical data set for the Neotropics,
  2. Characterize the landscape-scale variation in pollen assemblage and chemistry composition, and
  3. Identify the key environmental drivers that determines pollen assemblage and chemistry composition variation.

Publication date: 27 July 2015
Closing date: 18 September 2015
Level of education: University (Masters)
Hours: 38 hours per week
Salary indication: €2,125 to €2,717 gross per month
Vacancy number: 15-286

Applications should be emailed to application-science@uva.nl, with in the subject line the position you are applying for and vacancy number (15-286). Please make sure all your material is attached in only one pdf. Applications should include a detailed CV including educational experiences, a list of research projects and/or publications, a letter of motivation, relevant work experience, and the names and contact addresses of two academic referees from whom a reference for the candidate can be obtained.

For more details, including information on how to apply, click here (UvA), or here (via academic transfer).

For further information visit the Palaeoecology & Landscape Ecology web pages, or contact Dr. William D. Gosling  directly.

Theses rush at The Open University

May 17, 2015
encarnimontoya

Hi palaeo-people!!

Alice Kennedy (far right) celebrating post-viva examination.

Alice Kennedy (far right) celebrating post-viva examination.

It is been a while since the Milton Keynes’s part of the group have manifested in the blog. The main reason is that we have been a bit busy basically…submitting theses!!!!

So this very short post is to congratulate Hayley Keen, Frazer Bird and Alice Kennedy for their recent handing in during the last two months and to celebrate that we have a new doctor in the group!!! Alice defended her thesis on 14th May, having as tribunal Prof. John Marshall (Southampton), Dr Phil Sexton (Open University) and Dr Sarah Sherlock (Open University). Next viva will be Hayley’s on 28th May (exam panel: Dr Dunia Urrego [Exeter], Prof. David Gowing [Open University], and Dr Mark Brandon [Open University]). Frazer will be defending his research next 25th June in front of Dr Pete Langdon (Southampton), Dr Neil Edwards (Open University), and Dr Sarah Sherlock (Open University).

Well done guys, this has been hard work and we are sure that your projects will have amazing contributions to high quality research!

Valencia PhD thesis 2014

March 5, 2015
WDG

Bryan-Kuelap-gate-2010-smallValencia 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.

Abstract
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.

Supervisors: Dr. William D. Gosling , Dr. Angela L. Coe (both The Open University) and Prof. Mark B. Bush (Florida Institute of Technology).

Examined by: Dr. Robert Marchant (University of York), and Prof. David Gowing (The Open University).

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

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