Everybody knows that the most-cited papers these days are mostly review and methods papers (see here and here). But exactly how predominant are such papers among the most cited papers in ecology? And what, if anything, does that tells us about the state of the field?
I searched Web of Science for papers published in the last 10 years in a long list of ecology journals, plus papers on the topic “ecology” published in the last 10 years in leading general science and general biology journals. Then I looked at the 150 most-cited papers from the ecology journals and the 100 most-cited ecology papers from the general science/general biology journals to see what sort of papers they were. Not an exhaustive or infallible approach, obviously, but good enough for government work.
As you’d expect, the bulk of these papers were review papers, methods papers, and syntheses/perspectives/conceptual frameworks. Continental- or global-scale data compilations and many-species data compilations were pretty common too.
In terms of topics, I didn’t do a formal tally. But climate change papers were really common. Particularly papers on range shifts and phenology shifts under climate change. Microbiome papers were very common among recently-published, highly-cited ecology papers from the general science and general biology journals, thus proving Meg right.* And not surprisingly, most of the methods papers were about statistical methods. Brian will be happy to hear that several of the most-cited ones concern statistical methods he likes–boosted regression trees, random forests, exploratory data analysis, etc.
What was rare or absent were (i) proper theory papers (as distinct from verbal “syntheses”, “perspectives”, and “conceptual frameworks”), and (ii) empirical studies on macroscopic organisms, based on data the authors collected themselves, or else on data from only a modest number of sites/species. I’ll call (ii) “small scale non-microbiome” empirical studies for short, although I’m obviously using “small scale” very vaguely.
One thing I found interesting was just how rare such papers were among the 250 recent, highly-cited ecology papers I looked at. So before we go any further, take a guess as to how rare they were:
The answer is…
About 15. Actually 16 by my count**, but I was skimming so might’ve missed a couple, plus a couple were borderline. So, well under 10% of the most-cited ecology papers published in the last 10 years are theory papers or “small scale non-microbiome” empirical studies. Which is a smaller fraction than I would’ve guessed.
A few comments, and some questions for you to discuss:
- This post is descriptive, not prescriptive. I’m not bemoaning or applauding the fact that highly cited ecology papers these days are almost all reviews/syntheses, methods papers, large-scale data compilations, and microbiome papers.
- Note that just because certain sorts of papers dominate the list of highly-cited ecology papers doesn’t mean they dominate the ecological literature as a whole. As I’ve noted in previous linkfests, other data show that ecological journals are not being overrun by reviews, syntheses/perspectives, and big data compilations. Those sorts of papers are a small fraction of all papers, and they’re not increasing in frequency very fast, if at all. No, not even if you restrict attention to leading journals.
- All of the 16 papers on my list are “small-scale non-microbiome” empirical papers. I suspect I’d have had to expand my search considerably to find any proper theory papers.
- To what extent does the lack of proper theory among our recently-published, highly-cited papers reflect our increasing collective focus on climate change, vs. maturation of the field (we have the right ideas, we just need to apply those ideas now)? That is, if anthropogenic climate change weren’t happening, and so weren’t a focus of so much research attention, would a lot of the people working on climate change be developing and citing new fundamental ideas instead? I’m not sure.
- Are verbal “perspectives”, “syntheses”, and “conceptual frameworks” increasing in frequency and prominence at the expense of proper theory? If so, why? I confess I don’t often find such papers very useful myself, and I’m not alone in that. Historically, most of the successful new theories and concepts in ecology have been simple mathematical models that did not not develop from data synthesis or verbal conceptual frameworks (e.g., island biogeography theory, optimal foraging theory, resource competition theory, metapopulation theory; some would add neutral theory, r/K selection, and MaxEnt to this list). And verbal syntheses, perspectives, and conceptual frameworks have a stubborn habit of not developing into proper theories. Now, you could reply that these days, ecologists want system-specific models rather than general theories, and you might be right. But verbal perspectives, syntheses, and conceptual frameworks aren’t notable for spawning system-specific models either.
- There’s good mathematical theory on range shifts, phenology shifts, and their consequences. How come none of the theory papers on those topics are massively cited?
- Or alternatively, is looking at the most highly-cited ecology papers a bad way to diagnose and summarize what ecologists as a whole are thinking and doing? For instance, perhaps the fact that we all cite reviews of the effects of climate change just shows that we’ve all decided to use the same spin to “sell” whatever it is that we’re really working on.
- I’m now curious if/how the picture differs in other fields, like evolutionary biology. The challenge with that analysis would be deciding where evolutionary biology stops and genetics/genomics/bioinformatics begins.
Having post some deliberately-provocative but unanswerable questions, I look forward to hearing you argue in the comments! [grabs popcorn] 🙂
*Has Meg ever been wrong?
**My count, in no particular order: Sitch et al. 2008 GCB, Elith et al. 2010 MEE, Broennimann et al. 2007 Eco Letts, Heaton et al. 2008 GEB, Araujo & Luoto 2007 GEB, Inouye 2008 Ecology, Cornwell & Ackerly 2009 Ecol Monogr, Bell & Sih 2007 Eco Letts, Dingemanse et al. 2007 JAE, Lips et al. 2006 PNAS, Schindler et al. 2008 PNAS, Edwards et al. 2007 Nature, Franks et al. 2007 PNAS, Schindler et al. 2010 Nature, Maherali & Klironomos 2007 Science, Hector et al. 2007 Nature, Wittebolle et al. 2009 Nature.