The (r)evolution of ecology in the 1950s and ’60s (UPDATED)

Thanks to the influence of Robert MacArthur and other key figures, and external factors like the rise of environmentalism, ecology in the late 1950s and 1960s transitioned from an obscure and mostly descriptive discipline, to a modern science concerned with general principles and hypothesis testing and attracting significant public attention and support. It was recognized at the time that this transition was both needed, and already underway (see the ESA’s 1965 report on the state and future of ecology, which is a fascinating read).

But how did that transition come about, exactly? Was it really a matter of a few revolutionary geniuses like MacArthur coming along and demonstrating a totally new way to do ecology, which replaced the old-fashioned stuff? It sure looks that way if you look at the list of Mercer Award winning papers. Some of the Mercer Award winners from that time are foundational classics of modern ecology, while others are old fashioned papers that are now forgotten. By about 1971, the “competitive replacement” looks complete, and from then on the Mercer award always goes to recognizably modern work.

But if you look more closely within the Mercer Award winning papers, a rather different picture emerges…

(UPDATE: to my embarrassment, everything that follows is just an inferior recapitulation of stuff Mike Kaspari said much better in the ESA Bulletin several years ago. I’d either read Mike’s piece and forgotten it, or missed it, but either way it’s embarrassing. Thanks very much to Mike for sharing his piece in the comments. You should all click through and read it, it’s full of insight.)

Back in the 1940s through the early 60s, the Mercer award often went to site-specific, descriptive studies of plant community composition and succession. For instance, Dyksterhuis 1948, “The vegetation of the Western Cross Timbers”. The apparent exceptions start appearing suddenly in the mid-50s and early 60s, and jump out at a modern reader (at least, they do to me). Odum and Odum 1955! (the Odums! ecosystems! trophic structure! productivity!) MacArthur 1958! (MacArthur! competition! niche overlap! hypothesis testing!) Connell 1961! (Connell! competition! a field experiment!)

Seeing famous classics intermingled with now-forgotten papers makes you wonder about the internal deliberations of the award committee. How could they give the Mercer award to a descriptive study of succession like Olson 1958 one year, and to a pioneering modern study like MacArthur 1958 the very next year? And having given the award to a pioneering modern study, how could they ever go back to giving it to old-fashioned work?

Well, pretty easily, actually. Because when you go back and look at them, those pioneering modern studies don’t look totally modern. Rather, they’re a mix of modern and old-fashioned bits.

For instance, MacArthur 1958 starts by talking about general principles of population regulation and coexistence and how to test them, the first figure is the phase plane diagram of a Lotka-Volterra competition model, and there are a bunch of statistical null hypothesis tests. All very modern. But most of the paper is excruciatingly detailed observational natural history data on warbler behavior. There’s a whole table and associated discussion devoted to the frequency with which two species of warblers hop across branches as opposed to along branches! Most of this stuff is only tangentially connected to how warblers coexist, and it looks just like the descriptive case studies that modern work replaced. If you were being a bit uncharitable, you could argue that MacArthur 1958 is just Olson 1958 with null hypothesis tests and discussion of Lotka and Volterra bolted on.*

Which of course is a bit like saying that the Origin of Species is just natural history with speculations about evolution bolted on. Scientific revolutionaries are almost invariably transitional figures, and you misunderstand them if you see them as totally different from their peers. To pick a far more revolutionary example than MacArthur, consider Isaac Newton, inventor of modern physics and indeed modern science. But he was also really into alchemy. In his own mind, and in the mind of his peers, there was no discontinuity between his physics and his alchemy. It’s only from our contemporary perspective that Newton looks like a modern scientific genius who happened to have a bizarre, unscientific side interest in turning lead into gold. That doesn’t mean our contemporary perspective is wrong–that there’s really no difference between science and alchemy. It just means that scientific revolutions aren’t actually revolutionary. They’re evolutionary. In the early going, they always inherit many of the features of what preceded them. Indeed, insofar as they don’t, it’s difficult for them to succeed at all.

*Same for Odum and Odum 1955. Yes, there’s a lot in it that’s genuinely new–there’s a reason it’s remembered today! But there’s also a lot in it that’s very much of its time. For instance, there’s lots of natural historical description of the atoll with no obvious connection to general principles and hypotheses like pyramids of biomass or whether the reef community is in a stable steady state. Same for Connell 1961, if anything even more so. The transplant experiment along the environmental gradient for which we remember that paper is only a small part of it. Much of the paper is given over to detailed natural historical observations of weekly variation in barnacle settlement and mortality, comparison with past observational studies of where barnacles settle, the movement behavior of whelks, etc. And that stuff isn’t just background–it’s the core of the paper. Connell doesn’t pitch and summarize the paper as a study of general principles of species distributions along environmental gradients, or as an illustration of the power of a novel experimental approach. He presents it as an unusually detailed and accurate record of recruitment and survival under natural conditions. Indeed, having reread Connell 1961, I wonder a little whether, if you reran the tape of life and played it again, Connell 1961 would still end up as a foundational classic. That’s not to criticize Connell 1961 at all. It’s just to say that whether or not a paper ends up becoming a foundational classic is in part a matter of factors and forces outside the paper’s control. See this old post for discussion of how credit for the success of an idea should be apportioned: to the idea itself, or to subsequent work applying and using the idea.

18 thoughts on “The (r)evolution of ecology in the 1950s and ’60s (UPDATED)

  1. Great post, Jeremy, and it makes me want to re-read a few of those classics now. Except it also makes me think I’ll want to skip some passages, too…

    On your point about Newton: I very much agree, and it was broadly true of scientists and science at the time. Science and scientists were very much still finding themselves. Robert Boyle, remembered now for huge and “modern” contributions to physics and chemistry, also wrote papers describing odd deformities in farm animals – e.g. “Observables Upon a Monstrous Head”, in the first issue of the Philosophical Transactions. I wrote about this phenomenon here:

    So, a question. If we stopped thinking about progress as a series of paradigm shifts, would that be a paradigm shift? 🙂

    • “Except it also makes me think I’ll want to skip some passages, too…”

      Yeah, same here.

      This exercise also gave me a new appreciation for just how modern Gause was. The Struggle for Existence sounds *far* more bang up to date than MacArthur 1958 or Connell 1961, at least to me. The famous time series data showing one species of Paramecium being competitively excluded by another are *not* surrounded by mountains of descriptive natural historical material.

      What’s even more remarkable is that Gause wrote SfE as an undergraduate.

  2. Just for the record, I could’ve used books as examples too. MacArthur & Wilson’s Theory of Island Biogeography of course has that famous theoretical diagram showing the stable level of species richness as a function of immigration and extinction rates. But it also has lots of natural historical material that would never make it into a comparable book today.

  3. Thanks Jeremy, timely contribution! We just finished up a readings course pairing classic papers such as these with modern examples on the same topic.

    What struck us most is how much natural history is present in these old papers, and how the lasting contributions are buried deep within. Whittaker’s award winning 1967 paper is another great example: the partitioning of diversity bit doesn’t appear until 40 pages into a 60 page paper!

    I’m forwarding your post to the class right now…

    • “how the lasting contributions are buried deep within.”

      Which is what makes me wonder whether, if you reran the “tape of ecology” and played it again, the same papers would end up being regarded as classics. If a “classic” is “an otherwise-ordinary paper that had one bit that subsequent ecologists found really important”, well, what subsequent ecologists find really important perhaps says more about those ecologists than about the paper. If you reran the tape, maybe ecologists would find bits of lasting value in other papers of the time, and the field would go off in a different direction. For instance, IIRC one of the late 50s/early 60s Mercer award winners included a big common garden experiment. What if subsequent ecologists got really excited by that and 1970s ecology ended up being all about local adaptation and other eco-evolutionary topics?

  4. One sometimes sees laments that natural history isn’t as synonymous with ecology as it used to be (discussed here: In light of that, a question: do the folks who feel this way prefer now-forgotten papers like Olson 1958 to classics like MacArthur 1958? And do they prefer the now-forgotten bits of MacArthur 1958 to the bits that are remembered today?

    Basically, what I’m asking is: what would a much more “natural historical” ecology look like? And if the answer is not “just like the sort of stuff that used to get the Mercer Award back in the 1940s”, then what is the answer?

    I confess to a bit of deliberate provocation here. I doubt that even the most natural historically-oriented ecologist today wants ecologists to go back to writing the sorts of papers they wrote in the 1940s, or thinks that the best bits of MacArthur 1958 are the bits about how often warblers hop across vs. along branches.

  5. “If you were being a bit uncharitable, you could argue that MacArthur 1958 is just Olson 1958 with null hypothesis tests and discussion of Lotka and Volterra bolted on.”

    Here’s a short PDF with another point of view. Kaspari M. (2008) Knowing your warblers: thoughts on the 50th anniversary of MacArthur (1958). Bulletin of the Ecology Society of America.

    Click to access 2008_kaspari_macarthurs-warblers_ecologybulletin1.pdf

    The upshot:
    “MacArthur (1958) is laden with well-articulated ideas, a great back-story, and object lessons on how some habits and practices stick, and others transform or disappear. If one wants to start a discussion on the nature of ecological science, publication, and communication, the warbler paper bears rereading.”

    You can download the SciArt by Debby Kaspari from this page

    • Very interesting piece Mike (and *much* better than my own post!). Thanks for sharing, I’d either forgotten it or missed it (to my embarrassment either way). Full of insightful remarks.

      I especially like your passing remark that MacArthur 1958 is very unlike today’s Mercer Award winning papers. My own thoughts on today’s Mercer winners:

      I also like your comment that MacArthur himself was accused of making the same mistake he urged his readers to avoid: merely documenting interspecific differences and then concluding that niche differences leading to coexistence had been demonstrated. As you (and Fretwell 1975) say, MacArthur cared most about throwing interesting ideas out there for others to run with. And as you say, it’s unfortunate that those who ran with MacArthur’s ideas often didn’t do a very good job of it–lots of follow-up descriptive work just trying to emulate MacArthur’s paper, without much in the way of alternative hypotheses, experiments, or evidence that the interspecific differences documented were actually the ones that allowed each species to increase when rare.

      And I’m *very* jealous of your line that scientific memes should be correct, but *have* to be infectious!

      In desperation to add something to what you had to say, and so partially make up for my embarrassment at having recapitulated a poorer version of your paper, I’d say that Lawton’s (1991) remark about MacArthur (1958) having discovered the “seeds of chaos” is a good example of “classic” papers only becoming classic in retrospect. The students in my graduate seminar on Darwin’s Origin do the same thing. They’re continually impressed by passing remarks in the Origin that seem to presage whole areas of modern ecology and evolution. Which, yes, do sometimes show Darwin’s prescience–but other times just show how easy it is to read modern ideas back into older work. This tendency on the part of modern readers is why it’s very easy to misread Darwin as having a modern understanding of how selection affects speciation, for instance. Finding the “seeds of chaos” in MacArthur 1958 strikes me as kind of like readers of Darwin’s time questioning his originality because there are passages in Erasmus Darwin or Buffon or whoever that sound modern to modern readers.

  6. “If you reran the tape, maybe ecologists would find bits of lasting value in other papers of the time, and the field would go off in a different direction.”?
    Is this though experiment valid in some other fields, physics for example?
    I do not think so.

    • “Is this though experiment valid in some other fields, physics for example?
      I do not think so.”

      My response to this line of thought is actually already in the queue as part of tomorrow’s post…

  7. it bears remembering that the content of a paper isn’t a pure expression of the thoughts of the author. Sometimes reviewers and editors ask for additions to be made or for subjects to be described in more depth. And before that, authors are acutely conscious of what peer-reviewers are likely to want or expect. At the time you’re talking about, I think there was a strong expectation you should show you had a detailed grasp of the field situation, before it was seen as appropriate to speculate (aka engage in theory) about how it might be interpreted.

  8. Has no one mentioned All Watched Over By Machines of Loving Grace? The BBC documentary miniseries, in large part about the Odums, ecology during that time, and social factors influencing the development of science in the US and Europe during that time? You can stream it online for free. Some good hist/soc of sci for undergrads or grads. Part 2, the hilariously named “Use and Abuse of Vegetational Concepts” is my favorite.

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