I am pleased to announce the start of a new project “Mapping Ancient Africa” funded by the International Union for Quaternary Research (INQUA) with support from the Palaeoclimate commission (PALCOM) and the Human & Biospheres commission (HABCOM). This project will bring together Quaternary scientists focused on past climates and environments with those working on human evolution and development in Africa. Through the synthesising data and linking these with modelling approaches we hope to bring together a novel group of researchers to explore the climatic and environmental backdrop to hominin development.
Further information on the project can be found on a new “sub-site” within this blog dedicated to the “Mapping Ancient Africa” project. The project is designed to connect researchers working on these topics so if you are interested to be involved please do get in contact. The first meeting will be held in October 2021 online and at four locations: Nairobi (Kenya), Port Elizabeth (South Africa), Potsdam (Germany) and Portland (Oregon, USA) – for further details click here.
The montane cloud forests of South America are some of the most biodiverse habitats in the world, whilst also being especially vulnerable to climate change and human disturbance.
Today much of this landscape has been transformed into a mosaic of secondary forest and agricultural fields. This thesis uses palaeoecological proxies (pollen, non-pollen palynomorphs, charcoal, organic content) to interpret ecosystem dynamics during the late Quaternary, unravelling the vegetation history of the landscape and the relationship between people and the montane cloud forest of the eastern Andean flank of Ecuador. Two new sedimentary records are examined from the montane forest adjacent to the Río Cosanga (Vinillos) and in the Quijos Valley (Huila). These sites characterise the natural dynamics of a pre-human arrival montane forest and reveal how vegetation responded during historical changes in local human populations.
Non-pollen palynomorphs (NPPs) are employed in a novel approach to analyse a forest cover gradient across these sites. The analysis identifies a distinctive NPP assemblage connected to low forest cover and increased regional burning. Investigation into the late Pleistocene Vinillos sediments show volcanic activity to be the primary landscape-scale driver of ecosystem dynamics prior to human arrival, influencing montane forest populations but having little effect on vegetation composition.
Lake sediments at Huila from the last 700 years indicate the presence of pre-Hispanic peoples, managing and cultivating an open landscape. The subsequent colonization of the region by Europeans in the late 1500’s decimated the indigenous population, leading to the abandonment of the region in conjunction with an expansion in forest cover ca. 1588 CE. After approximately 130 years of vegetation recovery, montane cloud forest reached a stage of structural maturity comparable to that seen in the pre-human arrival forest. The following 100 years (1718-1822 CE) of low human population and minimal human impact in the region is proposed as a shifted ecological baseline for future restoration and conservation goals. This ‘cultural ecological baseline’ features a landscape that retains many of the ecosystem service provided by a pristine montane forest, while retaining the cultural history of its indigenous people within the vegetation. Continue Reading
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.
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.
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:
Generate the first modern pollen assemblage and chemical data set for the Neotropics,
Characterize the landscape-scale variation in pollen assemblage and chemistry composition, and
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 firstname.lastname@example.org, 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).
Valencia 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.
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.
The next INQUA Congress will be held in Nagoya (Japan) on July 27 – August 2, 2015
This is a call for contributions to session P05 on ‘Climate change in the tropical South Pacific during the Late Quaternary’.
The session abstract is as follows:
Establishing well dated, quantitative, highly resolved palaeoclimate data for the major climate systems of the tropical south Pacific has become a research priority owing to the paucity of instrumental data from this critical region of the Earth. Whilst the quantity of proxy climate data for this region is increasing rapidly, compared to records from the Northern Hemisphere there is a surprising paucity especially when considering the importance of this region to global climate. Such information is vital for fully understanding inter-hemispheric climate linkages, global energy fluxes and the long-term evolution of natural climate variability such as the El Nino-Southern Oscillation. The dearth of pre-industrial climate records from this region contributes to large uncertainties associated with future climate change impacts far beyond the south Pacific. This session aims to bring together researchers working on Late Quaternary ocean/climate proxies with those whose research lies in modelling ocean-climate processes and dynamics in the tropical south pacific region, and their implications for global climate.
We hope this session will be of interest to you. If you plan to contribute to this session, please submit your abstract before December 20, 2014 click here.
I am delighted to announce that later this year I will be moving to the Institute of Biodiversity & Ecosystem Dynamics at the Universiteit van Amsterdam. I will be taking up an Associate Professor position as head of the Paleo & Landscape Ecology group. I am excited, and honoured, by this appointment and look forward to intergrating my ongoing program of research with the world class team in Amsterdam. Over the next few months I am sure further details will appear on the blog about the move as plans evolve towards my start date in September. Exciting times…
In the light of my departure, at that of Emma Sayer (bound for Lancaster), The Open University, Department of Environment, Earth & Ecosystems is now advertising two posts (details below). I have enjoyed my time at the OU and I think there are still good teaching and research opportunities for academics here. If anyone whats to contact me about the posts then I am happy to discuss.
Lectureship Environmental Science (Advert)
Lectureship / Senior Lectureship in Earth or Environmental Science (Advert)
Course description: “Ecosystems is about the relationships between living organisms. Gain an understanding of the natural world and how the web of life works, with illustrations from around the world.”
Understanding how vegetation responded to past climate change requires the development of well constrained relationships between living floras, environment and climate. This project will help constrain the great uncertainty which exists as to how tropical ecosystems are represented in the fossil record by examining the relationship between modern vegetation and the pollen it produces. The project will analyse modern pollen rain using a combination of traditional microscopic analysis  and cutting edge geochemical techniques . We anticipate that the findings will provide new insight into past vegetation and climatic change.
For further information on the project and how to apply see the full advert: NERC PhD advert. Prior to applying please check eligibility for NERC funding by clicking here.
Closing date: 25th April, interviews will be held at The Open University during May.