How do you get to be a palaeoecologist?

Researcher profile: Dr Michelle Farrell (@DrM_Farrell)


As discussed by several GEESologists in our series of researcher profile blogs, it took me a long time to realise that what I do for a living now could actually be a real job! Even while I was an undergraduate student, it never occurred to me that several of the staff members in my department (postdocs, postgraduate students etc) were paid mainly to carry out research, and that research also formed a significant part of my lecturers' jobs. A career in academia was something that I knew very little about until I accidentally fell into one, and now I find it hard to contemplate doing anything else - I am incredibly lucky to have a job that I find so interesting.

I'd always been interested in natural history from an early age, mainly stimulated by childhood holidays in the UK and France. I grew up around two hours drive from the Lake District and Yorkshire Dales, and hiking with family and friends in these regions convinced me that I wanted to pursue a career that involved working outdoors. During a career-planning session at school we had to complete a computer-based questionnaire, which used our answers to come up with a list of suitable jobs. From this, one job that struck me as interesting was a national park ranger (some of the other options were a little less desirable, 'waste management operative' being one that has stuck with me over the years). I loved the idea of being able to work in one of the national parks that I enjoyed spending so much of my leisure time in, and wanted to help conserve it for future generations. With this in mind I went off to the University of Wales, Aberystwyth to study for a BSc in Environmental Science.

Growing up in the 1990s, when issues such as acid rain, the ozone hole and global warming were front-page news, I was looking forward to learning more about the effects that people were having on the environment during my degree studies. However during some of my introductory lectures at Aberystwyth, I discovered that people had actually been affecting the environment for thousands of years already, and that it was actually possible to study these past impacts. I became particularly interested in palaeoecology, though I never imagined that I would actually be able to pursue a career in this field. Circumstances prevented me from undertaking a palaeoecological dissertation in my final year, and I made do with an ecological one instead, still planning to follow a career in ecology and/or conservation.

When I began to search for jobs towards the end of my degree, I discovered that vast amounts of practical experience were required even for an entry-level ecology or conservation job. I had done some voluntary conservation work with the Aberystwyth Conservation Volunteers, and my degree had equipped me with some practical ecological skills, but it wasn't enough. Several months' unpaid voluntary work was needed to allow me to gain the necessary skills. Student maintenance grants had been abolished the year before I began my degree, and with a fairly hefty student loan to pay off I needed to find paid work. I took a job in sales, and while I learned some valuable people skills and gained a lot of administrative experience (both of which are very useful in my current role!), I soon knew that it wasn't what I wanted to do forever.

When a friend forwarded me a job advertisement for a research assistant at the Wetland Archaeology and Environments Research Centre (WAERC) at the University of Hull, I realised that the thing I'd found really interesting at university could actually be a job! I didn't have any practical experience, but as the advert said that training would be provided for the right candidate, I figured it was worth a try. Unsurprisingly, I wasn't shortlisted for interview, but Jane Bunting wrote to me and suggested that I apply for one of the funded PhD studentships that the Department of Geography were currently offering. Until then I had no idea that you could be paid to do a PhD, so I jumped at the chance. I had no access to an academic library, so Jane sent me a few key papers in the post, I put together a project proposal, and I was invited for interview and offered a studentship.

I moved to Hull to start my PhD in September 2005 and have been here ever since! My PhD used pollen analysis and a suite of allied techniques to explore concepts of marginality and the response of human populations to changing environmental conditions in prehistoric Orkney. I became very interested in integrating palaeoenvironmental and archaeological data, and was keen to work more closely with archaeologists on future projects. Archaeology was also something that I'd always been interested in, but despite being a big fan of Time Team, I hadn't even realised it was something you could study at university, let alone that it could be a job! 

Pretending to hold up one of the standing stones at Carnac on a family holiday to Brittany: apparently my interests in archaeology also began at an early age, though I didn't realise this until much later...

Hugging the Stone of Setter on Eday, Orkney during fieldwork in 2006: nothing much changes...

After defending my thesis, I continued to work with Jane as a post-doctoral research associate on the Crackles Bequest Project, which I'm sure will feature in future blog posts from one or both of us. During 2012 and 2013 I worked part-time on this project, as I was also working as a palaeoecologist for English Heritage as part of their Environmental Studies Team based at Fort Cumberland in Portsmouth. This gave me plenty of opportunities to work with archaeologists, and it was through contacts that I made here that I ended up working on my current project - producing pollen-based reconstructions of past land cover in some iconic Neolithic landscapes as part of the Times of Their Lives project run by Cardiff University and English Heritage. This will be the final project that I work on as a GEESologist at Hull - on May 1st I start work as a research fellow at Queen's University, Belfast, and will be working with archaeologists and other palaeoecologists on the FRAGSUS project, which is examining human-environment relationships in the island environment of Malta. This will be a big change after 8.5 years in Hull, but it's a challenge that I'm looking forward to and it's hopefully one more step along the path to the coveted permanent academic job!

I feel incredibly fortunate to have figured out how to be a palaeoecologist - it's challenging, much more interesting than most other jobs I can think of, and good fun too - I've been on some fantastic fieldwork at locations all over Europe and have met many great friends and colleagues along the way. My advice to anyone who is fascinated by a particular topic at university but can't imagine how it could ever lead to a career - ask your lecturer about it, you never know!

Conferences from the inside

by: Drs M. Jane Bunting and Michelle Farrell

Between August 5th and 9th, we were the hosts and organisers for a small conference with associated workshops (small = 35 people on the busiest day).  Organising a conference makes the experience of being at the event quite different - for a start, some days you don't even get close enough to the coffee table at break to grab a biscuit!

The meeting was supported by the Crackles Bequest Project, which pays Michelle's salary at the moment.  The goals of the conference are described here.  We'll write more about the research later as we get final results and work on the papers; this blog post is about the experience of organising a small conference.

The process began in January when we sent out emails checking the availability of our project partners (a wonderful group of people who provided all sorts of support for fieldwork in different parts of Europe, arranging permits, translating, bringing their students and colleagues along to help our team with the actual work, and being enthusiastic about what we are trying to do, which really helps when you're half-way up a mountain in the driving rain or crawling around in a haymeadow in thirty degree heat trying to identify a lot of very small green leaves, which does tend to start you wondering why this ever seemed like a good idea). We then set the dates so that as many of these people as possible could come, and began to plan in earnest.

The 'who can come when' spreadsheet was just the first of many.  We had to work out how much to charge for registration at the meeting, to cover printing abstract volumes and lecture handouts, provide copies of software and pens, and of course the all-important regular infusions of caffeine (and biscuits) to keep everyone alert.  We got quotes for a conference dinner and developed teaching plans for the workshops.  We booked rooms on campus, contacted the local conference bureau to get their help with negotiating some cheap rates with local hotels, and put together an advertisement to send out to the pollen-counting community via various mailing lists.  We even had lists of the lists we needed to make!

Although it felt like we did a lot of planning in advance, and the deadlines for booking to attend the conference and to get the hotel rates were relatively early on the 31st of May (over two months before), the week before the event ended up being manic.  I really should be used to that by now, but it always takes me by surprise.

Michelle demonstrates field methods in a field

We had fun stuff to do, for example sitting down with the menus from the campus catering service and choosing the options for the lunches (why yes, there WAS a chocolate option on the sweet platter every day, and twice it was brownies).  Michelle had a never-ending stream of emails - the pricing policies of the UK's railway system are baffling at the best of times, but trying to help someone travelling from abroad to find the best value ticket makes you question the sanity of the person who came up with it (or maybe they were just feeling particularly misanthropic that day?), and advising people who come from locations with very predictable weather on the possible conditions during the field day ("honestly, it could be pretty much anything, although snow is unlikely") reminds us that our normal is not anyone elses.  Friday afternoon found us settled in the committee room in our building with piles and piles of paper all over the big tables, assembling the handouts for the workshops - I got a bruise on the palm of one hand from banging the hole-puncher (yes, I should have done smaller wodges of paper, but then I'd not have got home before midnight) and Michelle stuck name labels on folders, assembled badges, and cut out individual slips of paper showing the menu choices for the conference dinner (we decided that would be easier than taking the spreadsheet to the venue or hoping people would remember what they'd chosen).  We moved furniture and put up signs pointing to the various rooms being used, and finally got to go home.

Attendees in the quad

I remember how hot the computer room got during afternoon practicals, an Indian attendee huddled in a coat after the dinner while the rest of us enjoyed the cool of the evening (it was about 18^oC by my car's temperature gauge - pretty cold if you come from the tropics I guess), some fabulous pictures of landscapes in a presentation about new work beginning in South Africa and some lovely data from more advanced projects, talking about science until my throat ached (and if you know me that's a LOT of talking) and a lot of laughing.  So here are a few pictures:

Before a session starts (in the earth science lab)

A summer's evening in the Hull docks area

As usual for conferences, people began to travel home at different points on Thursday, and by Friday afternoon only those who'd both stayed for the last workshop and had further to travel were still around.  We decided to meet up at a pub in Hull's docklands, where people could have fish and chips for supper if they wanted - obviously pub fish and chips are not as good as those purchased from a van (or shop in obscure location, depending on your particular favourite) and eaten out of paper, but they do come with beer.  Sitting around a table talking, teasing and gossiping like a group of old friends even though we'd mostly been strangers at the start of the week really brought home one of the benefits of this job to me - meeting other people who share the same strange interests and curiosity about how the physical world works, and having them become friends as well as colleagues.

Organising this meeting was a huge amount of work - I think we've finally dealt with the last of the expenses claims and bits of paperwork, and can sign off on the last spreadsheet, now it's October.  However, it is also very rewarding - all the intellectual stimulation of a conference PLUS you still get to sleep in your own bed, and don't have to put your pets in kennels.  But maybe we can all go to India or South Africa next time?

Vegetation survey in sunny Spain

by Michelle Farrell (@DrM_Farrell)

In my last blog post a few weeks ago, I gave a brief introduction to the science of palynology, or pollen analysis. Essentially, palynologists analyse the pollen grains preserved in ‘environmental archives’ such as peat bogs or lakes where sediments have accumulated in order to build up a picture of how the surrounding vegetation has changed over time. However, the interpretation of these pollen assemblages is far from straightforward, since pollen grains from different species vary in terms of size, shape and therefore dispersability, and there are also differences in the amount of pollen per unit plant produced by different species due to variation in plant reproductive strategies. For example, wind-pollinated plants need to produce much greater amounts of pollen than insect-pollinated species in order to increase their chances of reproductive success.

 

A key goal since the earliest days of palynology has been the quantitative reconstruction of past vegetation abundance from pollen assemblages. Models of pollen dispersal and deposition have now been developed, and estimation of Relative Pollen Productivity (RPP) is an essential for applying these models to reconstruction of vegetation from pollen records. Empirical estimates of RPP can be extracted from measurements of modern pollen assemblages and vegetation cover, and over the last 10-15 years considerable research effort has been invested in obtaining RPP estimates for key taxa. A recent review reported a wide range of RPP values for individual pollen taxa from different studies across Europe (Broström et al. 2008)‚ but since a standard methodology was not used to record vegetation cover it is not possible to determine whether these differences are due to variation in taxonomic groups (pollen grains can often only be identified to family or genus level, so in different regions a different assemblage of species may make up the palynological equivalent taxon Betula or Poaceae)‚ variations in environmental factors between study sites (e.g. climate‚ management)‚ or reflect the variations in methodology (Bunting and Hjelle 2010).

In May 2010, we held a workshop at the University of Hull which brought together several key researchers in the field of quantitative vegetation reconstruction from pollen records. At this workshop we came up with a standardised method of vegetation survey for obtaining RPP estimates. As part of the Crackles Bequest Project Jane Bunting and I, along with a team of European project partners, have applied this method to compare estimates of RPP within individual species across a wide climatic range and in different habitats. We’ll write more about the results of this project in future blog posts.

The majority of researchers who are interested in using models of pollen dispersal and deposition to quantitatively reconstruct past vegetation cover are based in north-west Europe, and as a result this is where most research activity to date has been focussed. The approach is now beginning to be adopted worldwide, and we are now collaborating with groups working in India, South Africa and South America to obtain estimates of RPP for common taxa in their regions. A little closer to home, research groups based in southern Europe are using the standardised vegetation survey protocol developed for the Crackles Bequest Project to taxa of interest for reconstructing Mediterranean environments. 

In June 2013 I was invited to join a team from the Pyrenean Institute of Ecology in Zaragoza, Spain on their fieldwork near the town of Teruel in the east of the country. Their research project is focused on the palaeolake at Villarquemado, from which they have recovered a 74m long sequence for pollen analysis. The group are now working towards estimating RPP for six key taxa in this sequence to enable them to quantitatively reconstruct the former vegetation in this area. I joined the group for a week to demonstrate the standardised vegetation survey methodology and to learn more about their research.

The palaeolake at Villarquemado, now mostly infilled and supporting fen-type vegetation

After a false start (I arrived at Leeds-Bradford airport on the day I was due to fly to Barcelona to find that all flights were cancelled due to a French air traffic control strike!), I eventually arrived in Zaragoza two days later than originally planned. I was met at the railway station in Zaragoza by my colleague’s husband, and we then drove for approximately two hours to the village that we would be staying in. Incidentally, if anyone is planning a holiday in this region you could do worse than to stay at the house we rented for the week – it was absolutely beautiful!

The following day we made an early start to avoid the worst of the heat (although I have to say that 30^oC was still a bit of a shock to my system, coming as I had straight from the miserable British summer that we had been having at that point!) and headed to one of the group's sampling locations. There are some differences between working in north-west Europe and in the Mediterranean region - for example in our fieldwork areas we normally collect a moss polster as our pollen 'trap', but since moss is pretty hard to come by in semi-arid Mediterranean environments 'Tauber traps' had to be used by the Spanish research group. These are essentially plastic containers sunk into the ground so that the top is at ground level, with a hole in the lid to allow the pollen rain to be collected. The team will return to empty the traps at the end of the flowering season to ensure that a full year of pollen rain is collected, so for now our task was to survey the surrounding vegetation.
 

The view from one of our sampling sites - very different to the lush green landscapes that I am used to working in in north-west Europe. Although I'm told that this is an unusually wet year and that everything is much more green than usual...

View from another sampling site, with the Tauber trap visible in the foreground

Once we had all got to grips with the intricacies of the survey method, the team worked incredibly efficiently, and we managed to survey all 12 sites in five days. We also had fantastic logistical support from the husbands of two members of the survey team, who arrived to meet us every lunch time with hampers full of goodies to fuel us through the afternoon! For me, there were huge benefits to joining my Spanish colleagues for a week – I got to know people that I had previously met only at conferences much better, I made new friends, I got to experience fieldwork in a totally different environment to that which I am used to working in, and I learned a lot about Mediterranean plants and environments. I’m really looking forward to seeing the results once Edu has processed all the pollen and vegetation data from this field season!

Traces of tradition: looking for coppicing in the pollen record

                                 by Dr M. Jane Bunting



A schematic of the coppice cycle
(sourced from Greenway tree care)

Humans have been managing woodlands for a long time - archaeologists have found evidence for woodland management dating back 7000 years or more.  In historical times, one of the most widely used types of management was coppicing, the practice of cutting shrubs down to ground level to encourage the regrowth of many even-aged shoots.  This produced wooden rods of fairly even, manageable size for a huge variety of purposes; firewood, making hurdles and fences, stool and chair legs, walking sticks etc.  The length of time between harvests varies from three to over thirty years, depending on the species of woody plant involved and the desired size of the product.  

Felling of an area of mature coppice.  You can see a standard in
the right foreground, and some younger saplings which are
also being left to grow into standards (project picture).

In most woodlands, not all trees were coppiced. Some were allowed to grow into mature, single-stemmed adults ('standards'), to provide a source of larger timber for things like roof beams and door posts, tables and ship-building.










Coppice stool of hazel (Corylus avellana), about
ten years old, in Hayley Wood, Cambridgeshire
(project picture)

Today, coppicing is mainly used as a conservation measure.  Managed woodlands were and are usually divided into sections, called compartments or panels, and one compartment is harvested each winter.  This means that the woodland contains a mixture of areas with different ages of regrowths, providing a range of habitats, which increase the biodiversity of the woodland.



We know quite a lot about how coppicing was carried out in the middle ages from documents like estate records and accounts, but we don't really know how widespread it was in the landscape, and the further back we go in time, the less documentary evidence there is.  So we need to turn to other methods of finding out about the landscape, such as pollen analysis.




Any hay-fever sufferer will know that pollen is produced in large amounts and widely dispersed!  Some of those pollen grains end up falling into lakes or bogs and becoming part of the sediment layers forming in those waterlogged conditions.  The pollen analysis technique consists of collecting cores of sediment and extracting the pollen assemblages from layers of different ages, then using those assemblages to find out what the vegetation around the lake or bog looked like at the time when the layer was being formed.  The reconstruction process is not simple, and quite a lot of my research is concerned with trying to improve our ability to reconstruct past vegetation from pollen records or, as I like to think of it, improving the view out of the windows of a muddy time machine.

One of these projects involved working with Professor Martyn Waller at Kingston University and Dr Michael Grant, who was a post-doctoral researcher at the time, to try and improve our ability to spot whether coppicing was happening from the pollen record.  By learning more about how widespread coppicing has been in the past, how ancient the practice really is, and reconstructing the histories of individual woodlands, we hope to help improve the management of coppiced woods and conservation decision-making.  We used four different approaches to explore the effects of coppicing on pollen production:

1) studying when coppice regrowths began to flower, and how much pollen they produced.  Lime trees (Tilia cordata) took up to eleven years after being cut to produce even one flower on a whole coppice stool, whereas some hazel (Corylus avellana) flowered in the first year, and young regrowths (2-7 years) actually produced MORE flowers (and more pollen) than older ones, perhaps because as they grew taller they also began to shade each other more.



A small woodland pond, about 10m long (project picture)

2) using a computer model of pollen production, dispersal and deposition to see how these changes in flowering behaviour might affect the pollen record of a woodland pond depending on the coppicing regime practiced in the woodland.

3) setting out pollen traps to collect pollen for a whole year in coppice compartments of different ages.  The picture shows a 'Tauber trap' in the background, waiting patiently whilst a hole is being dug.  The traps were partially buried so that the opening was nearly at ground level.

4) studying pollen records from the last 100-150 years from small ponds in woodlands with documented coppicing histories


The first paper from this project summarised the findings from all four methods, and had to conclude that there is no one simple answer.  That doesn't mean that coppicing is invisible to the pollen record - we are continuing to analyse our data, hoping to find out more about the effects of coppicing on flowering behaviour and on the pollen signal.





Reference: Waller, M., Grant, M.J. and Bunting, M.J. (2012) Modern pollen studies from coppiced woodlands and their implications for the detection of woodland management in Holocene pollen records. Review of Palaeobotany and Palynology 187, 11-28

Palynology: why pollen is not to be sniffed at!

by Michelle Farrell (@DrM_Farrell)

To around 20% of the UK population, pollen is familiar as the cause of hay fever during the spring and summer months. To a very small minority (ironically, many of them well acquainted with the runny-nosed, itchy-eyed symptoms of hay fever themselves), pollen is much more than an allergen. Pollen grains contain the male gametophyte of seed-producing plants, and in order to increase their chances of reproductive success, wind-pollinated plants produce pollen in vast quantities. The small size of pollen grains (generally in the order of 20 to 40 microns, a micron being one thousandth of a millimetre) means that when they are released by a plant they become widely dispersed in the environment. As the plant has no control over where its pollen grains end up, another part of the reproductive strategy is that the grains have a very tough outer casing or exine, made of a substance called sporopollenin, allowing them to survive in less than perfect conditions. This outer wall can be preserved in several environments, particularly waterlogged ones, for tens of thousands of years. This combination of pollen being produced in large quantities, wide dispersal in the environment, excellent preservation under the right conditions, and the fact that pollen grains can often be identified to family, genus and even species level, is what makes them such a valuable tool for research.  

Coring to retrieve pollen-bearing sediments from a bog
on Orkney, Scotland

Pollen analysis is one of the most common methods used for investigating past environments. Pollen is often preserved in waterlogged environments where sediments accumulate, such as lakes and peat bogs. Cores of sediment can be extracted from these locations, and sub-samples from various depths are then subjected to a series of physical and chemical laboratory treatments which remove the majority of the inorganic sediments and large organic debris, leaving behind the fine organic fraction of the sediment. It is this fraction that contains the pollen grains, as well as other tiny organic remains including fern and fungal spores, other fungal remains such as hyphae, and fragments of charcoal from either natural or anthropogenic fires. The study of all these remains together is known as palynology, a term coined by the British scientists Hyde and Williams in 1944 and derived from Greek words meaning ‘the study of small particles sprinkled about’.


The stripes in this core segment indicate that the sediments
were deposited under different environmental conditions

Once you have concentrated the fine organic fraction of the sediment, the next stage is to identify the botanical remains contained within it. Much as a botanist would use a key to help them to identify plants out in the field, palynologists use keys to pollen and spores to aid their identification of specimens under the microscope in the lab. The identification and study of fungal remains is still a relatively new technique, and to date no definitive key to these types of remains has been published. Therefore I’ll focus here on the distinctive characteristics of pollen grains that allow palynologists to distinguish between the different taxa present in a sample. One of the most distinctive features of pollen grains is their apertures. There are two types of aperture: pori (pores), roughly spherical in shape, and colpi (furrows), which are elongated and have pointed ends. Some grains have both colpi and pori in the same apertures, and are known as colporate. The number and arrangement of the apertures is also key in pollen identification. The number of apertures is indicated by the use of the prefixes mono-, di-, tri-, tetra-, penta- and hexa- before the terms porate, colpate and colporate. The prefix poly- is used to denote the presence of more than six apertures. Usually the apertures are arranged equidistantly around the equator of the pollen grain, and this is indicated by the prefix zono-. Panto- is used when the apertures are scattered all over the surface of the grain. Some examples of the way in which apertures are used to identify pollen grains are shown below.



Betula (birch) pollen: trizonoporate,
with three pores arranged equidistantly
 around the equator of the grain

Fraxinus excelsior (common ash) pollen:
trizonocolpate, with three furrows arranged
equidistantly around the equator of the grain



Rumex obtusifolius (broad-leaved dock):
tetrazonocolporate, with four apertures
made up of both colpi and pori

Plantago lanceolata (ribwort plantain):
polypantoporate, with many pores scattered
all over the surface of the grain

The pattern of sculpturing found on the surface of the exine is another crucial factor in the identification of pollen grains. Around fifteen different surface patterns have been described, and two of the more distinctive patterns are shown in the images below.


Cirsium arvense (creeping thistle) pollen, a
good example of echinate surface sculpture



Ulmus (elm) pollen, displaying rugulate
surface sculpturing

Size can also be important in distinguishing between pollen taxa, particularly members of the grass family. The two images below show the difference in size between a wild grass, Phragmites australis (common reed) and a cultivated grass, Triticum aestivum (wheat).


Phragmites australis (common reed) pollen

Triticum aestivum (wheat) pollen








The identification and recording of pollen grains from different depths within a sediment core can be used to provide information on how the vegetation surrounding the core site has changed over time. Sediment cores can often be accurately dated using radiocarbon, allowing the changes in environment to be tied to a chronology. Palynology has great potential for providing baseline data for the development of conservation management strategies, and is also useful from an ecological perspective as it can give insights into how plant communities have responded to climate change in the past, thereby allowing predictions to be made about how vegetation and ecosystems may be affected by future climate change.

One of my main research interests is in the use of palynology as a tool to unpick the ways in which humans interacted with their environments during the Holocene (the period since the end of the last ice age, approximately 11,500 years ago, until the present day). I intend to write more about the archaeological applications of palynology in future posts, but as a taster, it is possible to determine when people began farming in an area, what crops they were growing, where they grazed their animals, whether they cleared woodland to create more land for agriculture, and how they contributed to the development of cultural landscapes such as heathlands. It is also possible to investigate the ways in which people may have managed their environments and responded to climate change in the past, for example managing heathland by deliberate burning in order to maintain the quality of grazing. It may even be possible to detect woodland management practices such as coppicing, and Jane Bunting will write about her work on this in the next GEES-ology post.