Michael Rosenzweig: an appreciation

I am currently attending a Festschrift this week for Michael Rosenzweig. Make no mistake, he is still actively doing science, but with 50+ years of scientific career, it seems like a good time to reflect on what an impressive career he has had. Just for full disclosure upfront, he was my PhD adviser, so I’m hardly the most unbiased reporter, but of course that gives me a close perspective.

Mike was awarded the Ecological Society of America’s Eminent Ecologist award in 2008 and he has well over 100 papers, many massively cited, and three books, so I imagine many are familiar with his published work, and it would take too much space to summarize it anyway. I want to offer several more reflective and in some cases more personal thoughts. Take them as a reflection of my respect and appreciation for Mike or my musings on the ingredients of a good scientific career as you wish.

If you think of a body of scientific work as a rectangle – possessing both length/breadth (diversity of subjects) and width/depth (profoundness of contribution) – then the area covered by Mike’s rectangle is very large indeed. He has been a major contributor to population dynamics (the eponymous Rosenzweig-MacArthur predator prey equations, often placed next to the Lotka-Volterra equations in undergraduate ecology courses worldwide). His work in density dependent habitat choice basically took the single species idea of the ideal free distribution and turned it into a tool for community ecology. And he literally wrote the book on species diversity (1995). The diversity of presentations at the Festschrift is emblematic of this. All of the work are of academic offspring (mostly first generation but some second generation) and are all quite clearly logical extensions of Mike’s own work. Topics range from macroecology especially but not only species area relationships, latitudinal gradients in diversity, coexistence mechanisms in desert rodents, conservation biology and environmental policy, evolutionary game theory, habitat choice the role of information in animal behavior, and etc. And sprinkled amidst these main themes, Mike has one-off papers, often highly cited, in numerous topics.  His most cited paper is the correlation between AET (actual evapotranspiration and productivity), but he has important papers on paleontological macroevolution in turtles, competitive speciation processes and so on. There is a select group of people who have impacted one field as profoundly as Mike has, but when you add in his breadth and diversity of topics (and how many of those fields he has impacted profoundly) it is a rare contribution.

But in no shape or form was Mike a one-dimensional paper machine. Probably his next best known contribution is as a journal editor. He has been an editor at ecological journals since the 1970s. But his seminal contribution and a major source of pride for Mike was founding the journal Evolutionary Ecology. This journal has played an important role in the growth of the field. And if that wasn’t enough, when Kluwer publishing (since swallowed by Elsevier) bought the rights to Evolutionary Ecology (along with thousands of other journals), they announced they were going to jack up the subscription price from a few hundred dollars per year to several thousand dollars per yea, Mike was horrified. He hired a lawyer, rallied the associate editors and launched a competing journal, Evolutionary Ecology Research which is still a major player in the field to this day. And having been there in his lab watching him during the transition, it was an enormous amount of work and came at no small cost to his career. The founding of a journal not once, but twice, to grow a field he cared about was an enormous act of altruism.

Mike is also an impressive undergraduate teacher, winning university-wide awards for his teaching. I was a TA in his main contribution – an undergraduate majors course in ecology. Two things stand out in my mind. First was how often that course got students out into the field (weekly). Ecology was not just an abstract subject but one that existed and was best taught in the field. I took that for granted at the time, but as I have moved around universities and realized how many ecology courses never go out in the field or only go out on a couple of field trips, I’ve come to realize how special that was. And Mike was a tour-de-force lecturing (this applied to his seminars as well). He was a very old school lecturer – a podium and notes on paper. But of course Winston Churchill was an old school lecturer too. Indeed I think orator was probably a better description for what Mike did. He commanded and carried an entire room. You could not hear a pin drop the entire hour.

Of course Mike mentored graduate students too. The fact that the vast majority of his graduate students and postdocs have made the time to travel from around the world to come to this Festschrift is telling. So is how many of his former students have commented during their talks something like “he taught me how to think like a scientist” (something I said during my own PhD defense). In many ways he was on the hands-off end of the spectrum as an adviser, and students worked on just about any system they wanted to work on, so they weren’t learning the mechanics of field work or experimental design from him. But the ability to differentiate good science from bad, to know when you were going after a worthwhile question, knowing how to cut through the clouds and produce substance, and knowing how to think strategically about research all were things he shared with his students. He not only does these things well himself, but he had the harder knack of transmitting them to his students. He also taught me (and the whole ecological community) a lot about good scientific writing. If you haven’t read pages xv-xvi of the introduction to his 1995 book, do so. It is a manifesto for improved writing in ecology and science. As I am currently writing my own book, I frequently flip his 1995 book open for inspiration on how to write compellingly.

I still to this day remember several very precise nuggets of scientific wisdom that Mike passed on to his students as we read and discussed papers together. One was “a species is whatever a trained taxonomist in that group of organisms says it is”. This was a lovely way of at once acknowledging the reality that a species is a much more slippery concept than the high school text books would say, but at the same time reminding us that the species was a very important concept and we could operationalize it enough to move on to the more important questions. Another was “organisms choose their own niche”. This was said frequently in response to papers that tended to assume niches were a fixed property of species and independent of context (e.g. the presence of other species). This idea was also closely tied to the one big idea of Mike’s that should have caught on but never did. Namely, the distinction between the traditional view of niches as non-overlapping or distinct preferences, vs. what appears to be the much more common organization of all species having the same preference but different abilities to capture that optimal spot trading off with different abilities to tolerate suboptimal environments, known as shared niches. This idea to me appears everywhere one looks and explains a great many shortcomings in theory of the niche, but never really took off. His definition in his 1995 book of a biogeographical province as the self-contained region that contains the speciation and extinction events, which might be as small as Hawaii or as large as Asia, was another great example of cutting through the smoke, putting processes front and center, and giving an operational, useful definition. It requires a certain bravery to simplify things that much, as they are easy to pick apart, and certainly a lot of wisdom to pull out the central issue, but those individuals able and willing to do so greatly advance science.

Another one of his phrases is “truth is found at the intersection of multiple lies”*. By this he just meant that models are flawed, field systems are flawed, lab models are flawed, but when they all rub against each other and agree you have really got something. A closely related idea was his publication of the notion of the dipswitch test of theories – the idea that while ecological predictions may often be weak predictions like  “it will increase” or “it will decrease”, that when one theory can start to make a bunch of such weak predictions it adds up to a strong test of a theory (he describes dipswitch theory in this paper on isolegs and I also discuss it in my post on predictions).

I also remember a conversation with Mike around my first paper, a test and critique of Hubbell’s Neutral Theory. Mike was supportive of that paper and saw the need for it in the context of the hype around neutral theory, but he also told me “my adviser told me that you should let other people clean up other people’s messes”. A great example of academic wisdom passing across generations. But he was also clearly telling me that good scientists build their careers on building new ideas, not on attacking other people’s work and not getting embroiled in controversies that are likely to end in a fizzle without clear resolution.

This is part of a larger strategy of Mike’s. He clearly marches to his own drummer as a scientist. He is incredibly well read, yet he also seems oblivious to what is currently hot or not hot. He doesn’t have much truck for scientific fads or bandwagons. Instead, he pursues things he himself thinks are important. And he pursues them how he thinks best. And he is right really often. Its easy to pursue the crowd, but it is harder but ultimately more rewarding to pursue importance. In the same vein,  Mike does not believe in minimum publishable units (MPUs). Many of his papers are quite long (so long they might not get published today) with a rich diversity of interwoven ideas. The kind of paper you could read five times and get five completely different things out of it. And once he says what he has to say, he doesn’t feel any need to repeat it. There is little doubt that repeating the same idea over several papers is an effective way to get it noticed and remembered (and we can all think of people who have built successful careers this way). But to Mike it is a waste of his and everybody else’s time. Mike once told me that the invention of the word processor ruined science – pre-word-processor typing and modifying a paper by hand was real work and one only did it if one had something really important to say, but the word-processor effectively lowered the cost of producing MPUs. One of Mike’s highest forms of praise of somebody is to say “he/she is not a careerist, they are a scientist”. By this he means they pursue good science and do not pursue citations, long CVs and fame. And Mike clearly lives to this standard very highly himself.

An example of marching to his own drummer is how he does theory. Like many (most?) great ecologists, Mike is both an impressive field biologist (he has trapped more small mammals than anybody cares to count and has an impressive life list of birds) but also a very good theoretician. However, the way he does theory is not the way most people do theory. Most theoreticians either have learned the mathematical tools of the trade of writing and solving equations or they have gotten good at writing computer simulations. But there is a third approach that shares all the desirable features of simplifying the world to a domain in which rigorous logic can occur. Namely that of graphical reasoning. Mikes ability to draw and then reason from graphs is astounding. He looks at a curve and immediately thinks about whether it is accelerating or decelerating, whether it is asymptoting or not, where it crosses zero, etc. And then almost uniquely he can start thinking about the ecological and evolutionary dynamics from those curves. If you read his original 1963 paper on the Rosenzweig-MacArthur predator-prey dynamics, there were equations with formal stability analysis in there, but they were clearly almost an afterthought. He got to all the questions and all the answers by thinking carefully about the implications of the ZNGIs (zero-net growth isoclines). He even drew and reasoned about three-dimensional isoclines (three species food chains) graphically, possibly the only person to ever do so. His development of isoleg theory (density dependent habitat selection) and the evolution of isolegs was another example. To my knowledge Richard Levins (obviously another very important figure), was the only other person to as successfully build theory from purely graphical models.

Mike’s biggest contributions are all in the area of basic research in ecology and evolution, but throughout his entire career he has had an interest in doing policy-relevant science. Two of his three books are popular books translating the implications of ecological theory into policy. And he has been members of various commissions and blue-ribbon panels with policy implications throughout his career. As in his basic research, he has largely done this by his own pursuit of important ideas. Rather than trying to outdo the conservation biologists in their own subjects of population viability analysis, population genetics, etc, he thinks outside the box and finds ways to connect big ideas in basic ecology to policy. And once he is sure of his scientific foundation, he is unflinching in thinking through the implications for policy. This goes as far back as his discovery of the paradox of enrichment in predator-prey cycles. And in recent decades he has focused on his expertise in species area relationships and recognizing what he calls “the tyranny of area” (the single biggest predictor of species richness is area and there is no escaping the consequences of lost area) to develop the field of reconciliation ecology (if area is so important we can’t afford to write off all the area humans occupy as unavailable to wildlife so we need to move past reservations to land-sharing). He has spent much of the last two decades since the publication of his book on reconciliation ecology, Win-Win Ecology,  trying to implement reconciliation ecology in a practical fashion here in Tucson, an ongoing effort of his.

One of the things people who have met Mike only briefly remember most about him is his booming laugh. He also possesses an equally booming voice and the ability to hold a room spellbound.  Mike is full of opinions and can easily fill a conversation with his own opinions, but he is more than willing to listen too. And to ask good questions. He is not in the least hierarchical. He is equally willing to listen to a grad student as an eminent ecologist (in fact he values intelligence of ideas contributed over reputation). I probably learned more about science from my one-on-one conversations with him as a graduate student than I did from any other source. I remember at one conference I knew two of my colleagues (both tenured professors themselves at that point) had never met Mike and were awed by his work and reputation, and so I asked them to join myself and Mike for lunch. I remember clearly how afterwards they both commented to me how down to earth and what a nice person he was.

But perhaps the single thing I am personally most grateful to Mike for is something only those close to him got to know. He strongly models by his own actions that one could be a successful scientist at the same time one prioritized one’s own family and in his case religion but more generally life outside of science. One of the reasons I chose to go to U Arizona and work with Mike as a graduate student was because even during my short interview it was clear to me he thought about family as much as science. And I quickly realized as a new graduate student that there were days he wouldn’t be in the office because he was home with sick grandkids, etc. That was not entirely typical for a top scientist, especially a male scientist of his generation. As somebody on the verge of starting a family myself this was an important example. And amidst  the environment of a competitive graduate program where some advisers would drop in on a Saturday and leave notes on the desk of anybody who wasn’t in the office, it was wonderful to have an adviser who not only allowed me to but would have thought I was stupid not to take off 6 weeks after my son was born amidst my end-game push on my dissertation.

Its not to hard to note across all of these stories that integrity and wisdom are found every bit as much as the traditional scientific ingredients of intelligence, creativity and hard work. I am very grateful to Mike for all that I have learned and gotten from him. And being here amidst all of his other graduate students, I am reminded that we all have a great deal in common in how we approach science (and life) and thus the heritability of these traits is high and directly attributable to Mike. And ecology is lucky to have his contributions to science as well as his contributions in areas like the journals he founded.

What are your experiences with Mike? What work of his influenced you the most? Do you feel the way you do science has been inspired by him at all?

 

*(UPDATE) A couple people have pointed out to me that this is very close to a published quote from Richard Levins 1966. To be honest I’m not sure of the origins or if there was an independent coevolution. The one thing I’m sure of is that if Mike got this from Levins, he would have said this to his students when passing it on, and it would be me forgetting that part. He was an extremely careful scholar – I have vivid memories of him attributing statements to whoever said them ALL THE TIME.