NERC ‘Scenario’ DTP PhD project at University of Reading:
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.
Collaborator: Jose Iriarte, Dept. Archaeology, Univ. Exeter.
The Parana pine (Araucaria angustifolia) of southern Brazil is an iconic ‘living fossil’, dating back to the Mesozoic, when it was likely grazed upon by Sauropod dinosaurs. This evergreen conifer once dominated highland areas of Brazil’s southern Atlantic Forest (a global biodiversity hotspot) until the colonial period, but is now critically endangered and is a key conservation priority. To gain a robust understanding of the likely response of Parana pine to future climate change, a better understanding of the underlying reasons for its current biogeographic distribution is first needed, which can only be gained via knowledge of the long-term dynamics of this species over the past several millennia, in relation to both past climate change and pre-Columbian (pre-1492) human land use. The overall aim is to determine the relationship between Araucaria forest, climate change, and human land use over the past ~ 6,000 years in southern Brazil, and thereby improve understanding of the likely response of this species to future climate change and the implications for conservation policy. This PhD project complements an ongoing AHRC(UK)-FAPESP(Brazil)-funded project which provides the archaeological context.
Approach and Methods:
The student will use a novel, multi-disciplinary approach, which combines palaeoecological and archaeological data with ecological and climate models. Fossil pollen will be analysed from bog sediments and fed into land-cover models (REVEALS, LOVE) to reconstruct the history of Araucaria forest over the last ~ 6,000 years. These data will be integrated with ongoing archaeological studies and previously published palaeoclimate records to determine the respective roles of people versus climate change in driving late Holocene Araucaria expansion. Climate models and ecological niche models (e.g. MAXENT) will be tested against these palaeo data and used to map the environmental niche of Araucaria through time, in response to past and future climate change.
Training will be given in field- (bog coring) and laboratory-based (pollen microscopy) palaeoecological skills (Mayle & Cárdenas), climate (Singarayer) and ecological (Walters) modelling, and integration with archaeological data (Iriarte). Sediment cores have already been collected, but there will be scope to visit the field area and collect further material if necessary and any relevant ecological data.
Applicants should hold a minimum of a UK honours degree at 2.1 level, or equivalent, in a relevant subject such as biology, geography or environmental science. A strong background in numerical/statistical techniques is essential and knowledge of ecology, microscopy and coding/modelling would be advantageous.
How to apply:
Full details of how to apply, as well as a podcast of this advert, can be found at:
The deadline for applications is 25th January 2016, although later applications may be considered. For further details about the project, please contact the lead supervisor, Francis Mayle.
This is the sequel to the post about “Guns” where we talk a little bit about where palaeoecology leads us when we follow our quest for investigating the past using lake/bog sediments.
An unusual patient
If you are worried about the consequences of working in palaeoecology, I can assure you that my recent visit to A&E was not because of an accident (and was not an accident either). This was a very well planned visit to the hospital to become more familiar with my beloved Brazilian patients, my bog cores.
Having taken over 110 Russian cores from numerous bogs across southern Brazil, between Frank Mayle and I (check out the Je Landscapes Project website to know more), I needed a quick non-destructive technique to visualize the internal structures of the cores so I could select the best ones for the project. I therefore decided to take x-rays of these half-metre cores. This relatively low-cost technique allows us to identify any key lithological changes through the core which are not apparent to the naked eye. The differences in density are seen in the resulting images as shades of light and dark. The lighter the colour of the image, the denser the sediment is. That is why features such as clastic material and tephra layers appear light, in comparison with organic peats which are usually dark.
So I arrived at the hospital with two oversized suitcases (Figure 2), completely filled with sediment cores (I am glad to say that I didn’t have to rush there). Carrying the cores this way allowed me to navigate easily through the labyrinthine hospital and get to the subterranean x-ray room.
The X-ray manager was very helpful, and we worked together as a great team, with me unwrapping the cores and placing them on the plate, taking notes and hiding behind the x-ray shield; while he was pressing the button and inputting the information into the computer (Figure 3). It was a relief to be on the other side of that shield.
The cores just about fitted on the x-ray plate (in diagonal) (Figure 4). I am glad I checked that beforehand! If you are considering taking x-rays of your cores, its important to call the hospital beforehand to make sure they have the plate size you need. It seems that most of the x-ray facilities only have the 23cm length plate, which is no where near large enough for a half-metre Russian core.
I am pleased with the results. The images allow me to distinguish internal structures and therefore enable me to select the best cores (some cores look fine from the outside, but with the x-rays I can see some small gaps in the sediment). On the other hand, the lithological changes revealed by the x-rays enable me to cross-correlate overlapping and duplicate cores. A particularly useful further step is to undertake grey scale analysis of the x-ray image, which can reveal even greater detail (Figure 5), especially when correlating with XRF and magnetic susceptibility results.
This was my first experience of undertaking x-ray analysis of bog cores, and I must say that I am very pleased with how useful this technique has proven to be.
Our quest for understanding the past, using sediments pushes us to find ways to extract the information in what is sometimes quite an exotic manner, as well as making us visit unexpected and fun places (soon to come, a blog post about the places we have visited lately in our field trips). Here is an example of the fun things we get to do.
No blood involved
One fun activity we have been doing is: holding a gun. Not any gun, but a galactic-looking laser-shooting one. I am talking about the portable x-ray fluorescence (XRF) analyser (Thermo), a fantastic piece of technology that allows us to analyse a wide range of elements from the Periodic Table (Figure 1). The gun is very easy to use, with touch-screen and flexibility to customise it, depending of the nature of your sediments. Beware that, because of the nature of this piece of kit, you will need to undertake training in radiation. And: make sure that if you are using it in hand-held format for long periods, that you have strong biceps!
Results from this technique have several applications that go from cross-correlating cores within a site to understanding the past environmental characteristics and deposits of the sediments. The fast processing time and resolution available with this method (1cm) enable results to be obtained very quickly, and allow one to understand the nature of the sediments in a non-destructible way (which is very much appreciated when you have only small volumes of sediments at your disposal with Russian cores!). The results can be imported into the computer and easily opened in an excel spread sheet (Figure 2).
Next steps will be correlating the XRF results with other analyses, such as magnetic susceptibility and pollen analysis. I am really looking forward to seeing what these multi-proxy analyses reveal.
Je Landscapes project and kids
Click the photo to see about how kids got fascinated with what we had
to say about the Monkey Puzzle and our Je Landscape fossil material
TPR to the South East of Brazil: Je Landscape Palaeo fieldtrip
It is not long since I came back from the Jê landscapes Project field trip in the South east of Brazil.
The experience was truly fantastic. I had the pleasure to meet and know incredible landscapes and generous people. As a result we found fantastic sites and collected what we believe are the best representative materials for our project.
Focusing in the vegetational, environmental and climate reconstruction during the existence of the Proto- Jê culture, the aim of the field trip was to collect sediments from bogs at the main three geographical areas where the project is studying the Jê culture: Urubici (Highlands), Rio Fortuna (were the Atlantic forest is) and Campo Belo do Sul (Highlands). Armed with dutch gauge and Russian corer, me and my fantastic assistant Álvaro Costa toured over 200 kilometres within Santa Catarina region looking for deep bañados.
Our experience in Urubici started very challenging. The very first bog we tried coring was what I would say the most difficult of the whole trip. We simply couldn’t extrude it. It was a clay and silt grey sediments with a large proportion of silica that would stick to the inside of the Russian corer like leeches, and not even using spatulas to do toggle we could extrude them. Long story short, we managed to find a way to extrude without disturbing the sediments and from that moment onward nobody stopped us. We cored 13 sites within the area, all with overlapping and duplicate drives.
Our experience in Rio Fortuna, towards the littoral side of Santa Catarina, was indeed a very different but not an easier landscape to core. To find a bog that didn’t suffer the consequences of agriculture or cattle, or that wasn’t converted in a fish tank to grow trout was the first but not only barrier; being able to cut across with the Russian corer the dry and sandy sediments was another one. We would not give up, and using as much of our patience as well as our weight to push we recovered sediments from four sites very close (~100m) to archaeological finds.
Campo Belo do Sul gave us a little truce. Thanks to Frank Mayle, who already went to the area in April 2014 and cored eight fantastic sites, we weren’t in much need to core much more. I personally enjoyed this part of the field by joining to the archaeological team that was in the site excavating Abreu e Garcia (funerary) and Baggio (oversized pit-house) sites. An army of students, plus researchers Dr Mark Robinson, Dr Rafael Corteletti, PI Professor Jose Iriarte, PhD students Jonas Gregorio and Priscila Ulguim and of course, loads of yerba mate there were many hours of tireless digging.
Another fruitful stop was in Gateados farm, a timber company committed to preserve and protect native vegetation. With the crucial help of Professor Lauri Schorn and his student Alyne Rugiero from University of Blumenau, we collected moss pollsters from the most pristine Araucaria forests available in the area. We will use the pollen rain contained in these natural traps to understand how modern Araucaria forest vegetation expresses in the pollen record.
It was almost two very intense months of travelling, coring and falling, but I would definitely do it again. Now the next step is face the many hours of work in the field translated in sediments to unveil what the past of vegetation and climate was like when Jê culture inhabited these areas.
Almost forgot… I also found mosquitos…
Post by Macarena