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.
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.
POST has always supported #WomenInScience. Many brilliant scientists join us every year through POST fellowships, and help us produce our flagship briefings: POSTnotes. 1/11 pic.twitter.com/xaimqUXxBK
— POST (UK Parliament) (@POST_UK) February 11, 2019
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
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.
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.
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.
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 (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 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.
How well can you ever really know 5.5 million km2 of hyperdiverse forest? The Amazon region, and this question, are at the heart of several ongoing debates in the natural sciences – why are there so many species? how much carbon can the forest store? how much did ancient humans impact the forests, and can we still see their effects today?
This last question was the subject of a paper by Caroline Levis and colleagues published in the prestigious journal Science in March this year, which caused significant ripples within and outside the scientific community. In a nutshell, the article found that tree species humans have cared for are five times more likely to be forest ‘hyperdominants’ than you’d expect. Past human impacts also help explain where these species are found now, accounting for up to 20% of the variation in their distribution (for comparison, environmental factors explained up to 30%). The paper’s conclusion, as picked up by the media, is that “modern tree communities in Amazonia are structured to an important extent by a long history of domestication by Amazonian peoples.”
So, debate settled? Not quite.
I am aware that not many people had the great opportunity like me to attend PAGES OSM 2017. Therefore, I wanted to share some of the key things that got stuck with me after the conference.
There was an outstanding list of presentations and strong sessions. I am not aiming to pick a favourite, but I would like to highlight the following ones: “From the Mediterranean to the Caspian: paleoclimate variability, environmental responses and human adaptative strategies” with convener Ana Moreno et al, “Do species move or die” with convener N. Whitehouse et al, and specially “Disturbance dynamics across special and temporal scales” with convener Graciela Gil-Romera et al. Papers discussed there were largely multidisciplinary, and generated good discussions.
The Jê group: Farmers and sedentary
This time, written by scientific journalist Marcos Pivetta, this article covers what has been discovered so far by the archaeological research within the project and gives a first glance of what has been found from the palaeoecological research performed by Macarena L. Cárdenas and Frank Mayle.
To read the whole article click here, available in Portuguese. Right hand click in the page to automatically translate in google.
About FAPESP: São Paulo Research Foundation (FAPESP, Portuguese: Fundação de Amparo à Pesquisa do Estado de São Paulo) is a public foundation located in São Paulo, Brazil, with the aim of providing grants, funds and programs to support research, education and innovation of private and public institutions and companies in the state of São Paulo.
My views on the International Palynology and Palaeobotany Congress XIV IPC X IOPC
This is the first time I go to this joined conference and I have to say I am glad I made it. It is definitely an important event to know what is happening in the palynology world, as well as to let other know what you are doing. There were far too many names that did not make it, but there were abundant number of presentations.
It all started on Sunday 23rd evening with the opening ceremony, where each member of the committee gave the welcome. The speeches were followed by the signing of the Brazilian and the Bahia anthems by a talented Brazilian lady accompanied by a local guitarist. This was then followed by a traditional capoeira musical group that played a large round of songs that felt far too long for the taste of most. Capirinhas, local beer and typical Bahian food was waiting for us to wake us up again and start the networking.
Assessing the resilience of Brazil’s iconic Araucaria forest
to past and future climate change
Lead Supervisor: Francis E. Mayle, Dept. Geography & Environ. Science, Univ. Reading.
Applications are invited for the post of Graduate Teaching Assistant. The appointed person will be registered for a Part-Time PhD, while holding a contract of employment from the University of Reading which encompasses both doctoral studies and teaching responsibilities with an associated salary. The post will commence on 19th September 2016, for a period of 4 years. Although six potential topics are being advertised, only one post will be appointed to the strongest candidate.
Teaching duties: The appointed person will be expected to deliver seminars and tutorials to groups of 10-20 students on a regular basis, to undertake assessment marking and to undertake undergraduate dissertation supervision. They will be expected to complete the required training and development activities as specified by the Department, achieving AFHEA status within the first two years of appointment. Teaching duties will not exceed nine hours of teaching and learning work (of which no more than six will be contact hours) during term time.
The Parana pine (Araucaria angustifolia) of southern Brazil is an iconic ‘living fossil’, dating back to the Mesozoic. This evergreen conifer once dominated highland areas of Brazil’s southern Atlantic Forest (a global biodiversity hotspot), but is now critically endangered due to extensive deforestation and is, therefore, a conservation priority for Brazil. To understand its response to future climate change, a better understanding of the reasons for its current biogeographic distribution is needed, which can only be gained via knowledge of the long-term history of this species over several millennia. Was the documented expansion of Araucaria forest over the last several millennia a response to increasing rainfall, or a function of pre-Columbian indigenous peoples enabling its expansion due to its economic importance? To tackle this question, a novel multi-disciplinary approach is needed, which integrates palaeoenvironmental and archaeological data with ecological-climate modelling studies.
Remuneration: Tuition fees will be waived up to the level set for Home/EU postgraduate researchers, and the appointed person will receive a maintenance stipend and a monthly salary commensurate with their teaching duties.
Application: Please apply using the online application form at:
How to apply:
Full details of how to apply, as well as a podcast of this advert, can be found here
Three of our TPRG members will be giving a talk at this weekend’s Conference “Anthropology, Climate and Weather Conference” at the British Museum at our session:
The talks will include palaeoecological findings and the meaning for human and climate:
- Francis Mayle, Ruth Dickau, Bronwen Whitney, Jose Iriarte. Pre-Columbian raised-field agriculture in Amazonian Bolivia — What lessons for sustainable land use today?
- John Carson, Francis Mayle. Looking for anthropogenic forests in Amazonia: the potential and challenges in detecting a legacy of pre-Columbian land use.
- Macarena Cárdenas, Francis Mayle, Jose Iriarte, Lauri Schorn. Dynamics of the Brazilian Araucaria forest and its responses to human land use and climate change, a long term perspective
If you are around, come to see us!
Click here for more details