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

TPRG at INQUA

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! 

Oli

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.

Oli

 

Our study is published in Review of Palaeobotany and Palynology (https://doi.org/10.1016/j.revpalbo.2019.03.003). You can read and download it for free before the 22nd of May 2019 at this link: https://authors.elsevier.com/a/1YqF97uTvRX4z. 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, https://doi.org/10.1016/j.revpalbo.2019.03.003.

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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Anthropogenic Araucaria forests? New evidence published

A thousand years ago in southern Brazil, the unique Araucaria forest expanded rapidly over highland grasslands (campos), a change that’s largely been attributed to climate changes. At the same time, the southern proto-Jê people, whose diets and culture were interwoven with Araucaria trees, flourished. Given the close connections between the people and trees, and the timings of their expansions, might the Jê have been more important for that last forest expansion than the climate? So far, concrete evidence to address this question has been lacking – but two recent studies set out to provide just that. 

 

Araucaria forest at sunrise. Photo by Douglas Scortegagna (CC BY-SA 3.0, from Wikimedia Commons)

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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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Reflecting on a year in outreach – Plant Fascination, STEM clubs, 3MT and IASUK

I’ve found science fascinating for a great many years, and one of the things I enjoy most in life is helping others to catch some of that fascination for themselves. It’s a big part of the reason why I became a teacher before I started my PhD, and I’m so glad that science communication and outreach opportunities have continued to appear since then – after all, research shows it’s good for you, and for others. In this post, I want to reflect on some of the outreach fun I’ve had in the last year, and maybe encourage you to have a go too!

Fascination of Plants Day 2017 – the event that kicked it all off…

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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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