TPRG’s 2019 publications summarised

2019 saw the release of five papers first-authored by TPRG members, three of them led by Heather and one each by Maca and me. In an ideal world each could be explored in its own dedicated blog post, as with this one on Maca’s paper, but as time is constantly getting away from me I’m afraid these brief summaries will have to do! You can find the full and updated list of TPRG publications here.

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TPRG into 2020

I meant to write this post as a retrospective on 2019 at the end of last year, which gradually faded into a hope to publish it in early January. It’s now unavoidably the middle of February and the ‘new’ year is well underway, but so many TPRG things happened in 2019 that a review is still very much in order! Here’s a whistle-stop tour of some highlights… 

Farewells and hellos

Both Heather and Richard completed their PhDs last year, so huge congratulations to Drs Plumpton and Smith! In 2019 Heather also spent several months in the Parliamentary Office of Science and Technology, thanks to a fellowship with the British Ecological Society, before starting work at the Walker Institute as an Interdisciplinary Research Fellow

While it’s sad not to have Richard and Heather around any more, we’re very excited that Marco Raczka has joined the TPRG as a Postodoctoral Research Associate in Amazonian Palaeoecology (this post). He’ll be working on Frank’s new HERCA project over the next three years. Speaking of which… Continue reading


INQUA 2019, the quadrennial conference of the International Union for Quaternary Research, is taking place in Dublin over the next week, and we’re going to be there! Details of our poster sessions and presentations are below.

Josie has a talk entitled ‘Evaluating the resilience of traditional agriculture systems to climate change in the Peruvian Andes over the last 2000 years’ in the ‘Human-environment interactions in the late Quaternary: sources of evidence and applications 1’ session (29th Jul 2019, 16:45 – 18:30 in Liffey Hall 2, Level 1). You can read her abstract here.

James has a talk entitled ‘Millennial-scale history of Bolivian forest plots’ in the ‘Changing tropical landscape 2’ session (29th Jul 2019, 11:30 – 13:15 in EcoCem, Level 2). You can read his abstract here.

Oli has a poster called ‘Modelling the evolution of Brazil’s Atlantic Forest through the Quaternary in high spatial, temporal and taxonomic resolution’ in the Posters III session (29th Jul 2019, 14:30 – 15:15 in Liffey Hall A & B, Level 1), and is giving a talk called ‘The 3D Pollen Project: a new, free source of scans and 3D-printable models for outreach, engaging teaching, and research’ in the ‘Making the Quaternary relevant: Outreach and education’ session (27th Jul 2019, 16:45 – 18:30 in Liffey Meeting Room 2, Level 1). The abstract is here. You can find out more about the 3D Pollen Project on the project website, or on twitter.

And, while Frank won’t be at the conference (he’s doing fieldwork in Bolivia as part of a major new project – more on that another time), he and TPRG alumnus Richard are co-authors on Yoshi Maezumi’s paper Examining the Role of Natural and Anthropogenic Fire Activity on the Biogeographic Distribution of the Amazonian Rainforest Ecotone (ARE), also in the ‘Changing tropical landscape 2’ session.

We look forward to meeting you if you’re there! 


New research: modern pollen-vegetation relationships in Brazil’s Araucaria forests

A lot has happened since our last blog post in December! Heather and Richard successfully submitted their PhDs, James, Josie and I all had our PhD registration confirmed, and Frank has been awarded a significant grant from the AHRC (UK Arts and Humanities Research Council) and FAPESP (São Paulo research council, Brazil) for a major upcoming project. But while each of these things could probably have a post to their own, I wanted to give a bit of space here to look at a paper that Maca, Frank and I have recently had published.

Brazil’s Araucaria forests are iconic, diverse and ancient, but they’re also among the country’s most threatened ecosystems. 20th-Century logging reduced their area by up to 97% and, with their adaptation to relatively cool, constantly moist conditions, climate change is a looming threat. To understand how the forests will react it’s important to learn from their responses to past climate changes, but this is complicated because human activities may also have shaped the region’s vegetation dynamics in the 1,000 years or so.

An archaeological site at the Araucaria forest edge

Our study aimed to help disentangle these two drivers of change in the Araucaria forests by giving key insights into how the biome is represented by its key palaeoecological proxy, fossil pollen. We aimed to find out how well pollen rain could tell apart structurally different forest patches, and how over- or under-represented key trees were in their pollen. Although Araucaria forests’ modern pollen rain has been described before, this was the first time its relationship with the vegetation has been described in a quantitative way.

We found that, although structural differences between the forest plots were plain to see, they weren’t clearly reflected in the patches’ floristic composition. Pollen tends to have lower taxonomic resolution than vegetation surveys (it’s difficult – sometimes impossible – to tell the pollen of closely-related species apart), so it was therefore unsurprising that the plots couldn’t be distinguished by their pollen rain either. It’s possible that bigger or longer-standing structural differences would have been detectable, but this finding suggests that subtle human impacts in Araucaria forests may not be easy to pick up with fossil pollen.

This figure shows the differentiation of the forest plot types according to their vegetation (top row) and pollen (bottom row). Plot types are denoted by their colour and by their suffixes (op=open, cl=closed, di=disturbed, ro=rocky outcrop, sl=slope). The lack of coherent clusters in panels a and c, and the close spacing of the various plot groupings in b and d, show the patches’ similarity.

The difficulty of identifying complex changes in the forests is further emphasised by our second main finding. We calculated p/v values (a taxon’s pollen abundance divided by its abundance in the vegetation) for 27 tree genera. A p/v value of 1 would mean that a tree is equally present in both pollen and vegetation, a value of 2 would mean it’s twice as common in the pollen rain as in the landscape, a p/v of 0 means a plant’s growing nearby but isn’t found in the pollen sample, etc. Only five genera had p/v values higher than 1; by contrast, four had p/v values of 0, and 16 others had values less than 0.5. This means that pollen only provides good information on a small minority of the trees in this highly diverse forest – changes in the many under-represented taxa simply may not be captured. Logically, the over-represented taxa are the ones most often cited in palaeoecological studies, but these results suggest that analysing changes in rarer pollen types may also be important for understanding the ecosystem’s dynamics.

p/v values for 27 key Araucaria forest tree genera. Clethra technically has an infinite score (found in the pollen but not the vegetation survey); the paler sections for Lamanonia and Lithraea reflect different ways of calculating their values.

We hope this research helps find plot a path towards a fuller understanding of how past human and climate impacts on Araucaria forests are reflected in fossil pollen analyses. And, by putting numbers on the relationships between the forests’ trees and the pollen they produce, we hope to enable the increasingly accurate interpretation of these vital palaeoecological records.



Our study is published in Review of Palaeobotany and Palynology ( You can read and download it for free before the 22nd of May 2019 at this link: After that date, please get in touch if you want to read the article but can’t access it online.

Macarena L. Cárdenas, Oliver J. Wilson, Lauri A. Schorn, Francis E. Mayle, José Iriarte (2019), A quantitative study of modern pollen–vegetation relationships in southern Brazil’s Araucaria forest. Review of Palaeobotany and Palynology 265, p.27-40,

PhD opportunity: the domestication of Amazon rainforests by pre-Columbian societies

The domestication of Amazon rainforests by pre-Columbian societies 

Lead Supervisor: Francis Mayle, Department of Geography & Environmental Science, University of Reading. 


Application details: 


Co-supervisors: Joy Singarayer, Department of Meteorology, University of Reading; Richard Walters, Department of Biological Sciences, University of Reading. 


The extent to which pre-Columbian (pre-AD1492) human societies transformed Amazonia from a virgin wilderness into a domesticated landscape is one of the most contentious debates in tropical ecology.  The old paradigm of Amazonia as a pristine wilderness, little impacted by millennia of human occupation, has been challenged in recent years by remarkable discoveries of monumental earthworks across much of southern Amazonia.  However, although it is clear that these ancient ‘earthmoving’ societies transformed their physical landscape, the extent to which they also domesticated their forests – e.g. via burning, deforestation, agroforestry – is highly contentious.  The degree to which the biodiversity of Amazonian rainforests was shaped by millennia of human land use is highly relevant for understanding current patterns of biodiversity, rainforest resilience and land-use sustainability.     

The overall aim of this project is to determine the impact of Pre-Columbian societies upon Bolivian Amazonian rainforests – with respect to scale of deforestation, use of fire, and enrichment of forests with economically useful species. 

Approach and Methods: 

This project focuses on the monumental mound region of Amazonian Bolivia – a mosaic landscape of rainforests and seasonally-flooded savannas.  A dual data-modelling approach will be undertaken by the student:   

a)Palaeoecology– fossil pollen and charcoal will be analysed from lake-sediment cores to reconstruct local- and regional-scale histories of pre-Columbian forest impact over the last  2,000 years; i.e. scale of forest clearance and type of forest management (e.g. agroforestry, fire) associated with this mound-building culture.   

b) Modelling–an agent-based model will be developed (using NetLogo) to provide insights into the process by which this ancient culture domesticated these rainforests, and the extent to which a legacy of this ancient land use exists in today’s forests.  The student will parameterize the model using their palaeoecological data, together with previously published palaeoecological, archaeological and anthropological data, as well as floristic data from the RAINFOR ecological plot network.  

Training opportunities: 

Training in field- and lab-based palaeoecological techniques will be provided by Mayle, which will include a 4-week fieldtrip to the Bolivian Amazon.  Training in agent-based modelling will be provided by Singarayer and Walters.  Further training may be acquired via relevant NERC Advanced Training Short courses if need be.  

Student profile: 

At least a 2.1 BSc degree in biology/geography/environmental science is required.  A strong background in numerical/statistical techniques is essential.  Knowledge of ecology and microscopy would be advantageous. 

A summer of conferences

As a new academic year begins, students return and trees get geared up for autumn, it feels like a good time to look back at the various things that have happened over the summer months. Josie kicked off this mini-series with a post on her fieldwork in the Peruvian Andes and James is working on one about his research trip to Bolivia with Frank, so for a bit of variety I thought I’d give an overview of my summer of conferences. It’s less exotic than going to South America, sure, but I still had a good time! And there have been quite a few to report on…

The season’s first conference was Intact Forests in the 21st Century, at Magdalen College Oxford. I have to admit, initially I felt like a bit of an impostor – after all, I work on Brazil’s Atlantic Forest, one of the most fragmented forests in the world – but I was there in connection with a side project we’ve been working on looking at Amazonia. There’s a long, ongoing and quite contentious debate about where the biome sits on a scale from ‘pristine’ to ‘anthropogenic’, so for a few months we’ve been surveying researchers about their definitions of key terms used in these discussions. Do these differ with the respondent’s disciplinary background? Is my perception of a ‘natural’ forest the same as yours? And – relevantly for this conference – what do people mean when they write or read ‘intact’? Our poster had some results from a preliminary analysis of the survey, showing the diversity of opinions among our 30-odd respondents – if you haven’t taken part and would like to, then get in touch!

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A high-level assignment: fieldwork in the Peruvian Andes

During my two-week fieldwork trip to Peru this summer, I visited two of my PhD study areas, the Ancash District and the Chillón Valley. The Chillón Valley is home to one of the three main rivers that provide water for Lima and activities in this valley can have major effects on Lima’s water supply. Ancash on the other hand is home to two of the main mountain ranges in Peru, the Cordillera Negra and the Cordillera Blanca, so called because the former is unglaciated whilst the latter is formed of a number of glaciated peaks. It is thought that the Cordillera Blanca may one day look like the Cordillera Negra if glacial retreat continues at its current rate; this contrast between the two was interesting to see as the absence/presence of glaciers also affects the availability of water for irrigation and farming.

Whilst in Ancash we held a community workshop with representative from the local communities around the village of Pamporamas, in the Cordillera Negra, and a representative from a local NGO focused on rural development. This workshop discussed the issues surrounding water availability, and changes in this availability, as well as agricultural productivity within the highly sensitive Cordillera Negra. Following our workshop we visited a number of sites within the Cordillera Blanca, this involved visiting farming communities and seeing how agriculture is practiced today but also saw evidence for past agricultural practices in the form of relic terraces and field systems which would have been in cultivation during pre-Columbian times. We also interviewed local farmers whilst in the field to discuss the present day issues effecting agriculture productivity and sustainability within the study areas. This was an excellent opportunity to record local oral histories about changes in farming practices within living memory, to go alongside the deeper history perspective provided by the sediment core records we also collected.

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Fossil pollen at the Royal Institution

When was the last time you looked around you and wondered, ‘How on Earth did I get here?!’

I had one of those moments – possibly the biggest of my career so far – on April the 10th, in the Royal Institution‘s iconic lecture theatre. In one sense I knew the answer (from Kent via Victoria and Green Park underground station), but even now, two weeks after the event, I’m still trying to wrap my head around how I came to talk about my PhD research from the same spot as such renowned science communicators as David Attenborough, Richard Dawkins and Carl Sagan.

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Collaboration and training in Exeter and Southampton

Last month I was lucky enough to undertake a phytolith training placement at the University of Exeter in the Department of Archaeology, working with my second PhD supervisor, Professor Jose Iriarte, and his project team, PAST (Pre-Columbian Amazonian Scale Transformations).

During my four-week stay in Exeter, I processed and extracted phytoliths from a soil profile in the Upper Tapajos Basin of the Amazon, associated with a ditch enclosure. Once extracted, I then analysed and got training in the identification of the phytoliths. The phytolith extraction process can be quite lengthy and so it was great to have a lot of time to work through each of the stages properly. I had previously done some phytolith extractions for my master’s dissertation, however, I wanted to learn the methodology most suited to the tropics and South American samples.

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All change please

September is nearly over, the trees and weather have decided to get autumn underway, and campus is again buzzing as thousands of new and returning students arrive for the start of a new term. It seems like an appropriate time to reflect on a summer of changes here in the TPRG.

The first change, and possibly the biggest, was Macarena leaving us for pastures new at Earthwatch in Oxford. Since starting her post-doctoral research post in 2014, Maca had been a popular and integral part of many areas in SAGES (the School of Archaeology, Geography and Environmental Sciences) – to say nothing of her roles in the TPRG, managing the lab and running the blog. Small wonder, then, that so many people came to her farewell celebration!

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