The Cliff

Tenerife 2008 057 - students on the Aeonium field

Over the past few months I’ve been thinking a lot about PhDs and doctoral students, and our expectations of them, specifically in contributing to cutting edge biodiversity science.  In part this is because August 2013 will mark the 20th anniversary of the oral examination (“viva”) of my PhD at Oxford Brookes University.  The viva (short for the Latin phrase viva voce or “living voice”) is a peculiarly British method of examining PhD students that differs significantly from its (often public) counterpart in the rest of Europe and Scandinavia, and even more so from its equivalent in North America and the rest of the world.

For those of you unfamiliar with the viva process, I can recommend Simon Leather’s recent posting on the topic.

Since 1993 I’ve had the honour of acting as an examiner for 22PhD theses (4 at the University of Northampton, 18 externally) including two so far this year;  I’ve yet to turn down an opportunity to examine a PhD as it’s flattering to be asked and (more importantly) a great opportunity to see new ideas and data being generated by minds younger than mine.

One of the things that has exercised me recently is how much knowledge the average PhD student in my main discipline of pollination ecology actually has to get to grips with while doing the background research for their topic.  I wondered how this had changed since my time as a postgrad in the 1990s, and how the expectations of my own PhD examiners had changed since the 1970s.  So, using the wildcard term “pollinat*” in Web of Science I searched the contents of seven journals (Oecologia, Ecology, Journal of Ecology, Oikos, Annals of Botany, American Journal of Botany, & American Naturalist) that have published a significant proportion of the literature on pollination ecology over the past forty-odd years.

Of course I expected to see an increase in the number of papers on this topic being published per year over that time period, but not the two orders of magnitude difference that I found.  A PhD student studying pollination ecology in the early 1970s would be confronted with fewer than 10 papers on the topic coming from these seven journals whilst at the present time it’s averaging around 130 per year:

Pollination papers line graph

So it’s no wonder that PhD theses are tending to become more focussed as topics become more specialised.  So far, so expected.  But what I think is more interesting is the shape of the graph; why is there such a steep increase in the number of published papers in 1991?  I’ve nicknamed this point “The Cliff” because of its shape, and also because it seems to symbolise an intellectual barrier to be surmointed: an ability to read and synthesise a lot more information than was available prior to the early 1990s.  What is the reason for The Cliff?  Do other areas of ecology and evolution demonstrate a similar pattern in their historical rates of publication?  I see a link here to a discussion going on over at the Dynamic Ecology blog about the most cited ecology papers of the past few decades, and particularly the fact that “big ideas” papers are becoming less cited than review papers.  Perhaps it’s because we need these reviews to keep on top of literature that we’ve not got round to reading!

But that doesn’t explain why 1991 represents a step change for publishing in the field.  I’d be interested to hear the views of others working in pollination ecology.  What happened in the late 1980s to stimulate such an interest in doing research into plant-pollinator interactions?  Was it the publication of some key papers or books?  Did more funding become available specifically for work in this area?

18 thoughts on “The Cliff

  1. sleather2012

    Hi Jeff
    Coincidentally I have been doing a similar exercise for saproxylic insects, as part of a future post for my blog. There is a similar Cliff effect in the literature there too, but not until 1999 when publications suddenly double, gradually increase for a few years and then another Cliff effect occurs in 2008 when a similar doubling happens. At the moment we are in a relatively stable phase.

  2. Pedro Jordano

    Maybe an effect of several coincidental meetings focussing on pollination biology? Also the ’80s saw a steep development of research on coevolution as a process; this might have triggered an early ’90 burst in pollination studies. The ’80s also saw several pollination biology texts with exciting new ideas, clearly broadening the field. For instance, Richards’ Plant breeding systems (I think 1986) and Mary F Willson’s Mate choice in plants (also mid-80s), among several others. But really the cliff effect you pinpoint is very interesting and worth discussing! Thanks a lot for the excellent post Jeff.

  3. Jane Stout

    Nice post Jeff.
    How about 1992 Earth Summit in Rio and the signing of the CBD? Had a big influence on the publication of papers in invasion ecology. Also pollination now so popular and mainstreamed that it’s featured in much bigger range of journals.

    1. jeffollerton Post author

      Thanks Jane. I’m sure the Rio summit would have an effect in sustaining the literature later on, but research that contributes to The Cliff Ii.e. the 1991 peak) would have to have been conceived and funded and undertaken rather earlier, in the mid to late 1980s. Also note that, whilst your last statement is probably correct, I’m analysing data from the same 7 journals over that time period.

  4. Andre

    Could it be the null models in the 80s boosting publications in other areas that were mostly natural history before then?

    1. Andre

      A exercise taking a set of non-deeply ecological journals like the ones you took could give a glimpse about the processes going on, whether it was a revolution from inside the field or a external factor…

    2. jeffollerton Post author

      Maybe, interesting thought Andre. Though there’s more to a study being “ecology” as opposed to “natural history” than null models, I feel 🙂

    1. jeffollerton Post author

      Thanks Mary; perhaps that is sustaining the later parts of the graph, but it’s too early to explain The Cliff. And most of these papers are not concerned with honeybees.

  5. Pingback: Jeff Ollerton: The Cliff | Research Support Hub

  6. Paul Howland

    Interesting.. In my field, defence science, the cliffs occur as well. They are usually related to funding changes following a policy decision (often across a number of countries and organisations) with some latency for modifying priorities. There is also a multiplier, as those writing papers include a “new” keyword, relating to policy and funding change, in the papers they are writing. (Academic herd instinct, often having little of no impact on work content.. ) Hope this is not too cynical.. Paul

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