In 1971, Paul Dayton published a paper in Ecological Monographs providing experimental evidence for the role of physical and biological disturbances, as well as competition, in influencing an intertidal community off the west coast of USA. Forty-five years after the paper was published, I spoke to Paul Dayton about the making of this paper and the impact it has had on his career and our understanding of intertidal communities.
(Questions emailed on 3 September 2016; responses received on 25 September 2016)
Citation: Dayton, P. K. (1971). Competition, disturbance, and community organization: the provision and subsequent utilization of space in a rocky intertidal community. Ecological Monographs, 351-389.
Hari Sridhar: How did you become interested in marine ecology?
Paul Dayton: I grew up living a life mostly outdoors, first in Arizona, as my father worked on a ranch and in a deep gold mine, and then moved to Oregon where he worked first in logging camps, eventually trying to make a living selling life insurance after moving back to Arizona. In the logging camp era we started making Christmas trips to a, then very remote, bay near Guaymas, where I learned to snorkel, in 1952, when I was 11 years old. At that time marine life was not well known, as scuba gear was still being developed by Cousteau in Europe. To me it was also scary initially. I had spent most of my life outdoors and was very familiar with terrestrial systems, but this was utterly new and a huge challenge and I was hooked!
Dayton (white shirt, in middle) and friends on a ledge overlooking Shi Shi Beach and Point of the Arches (© Linnea Dayton)
HS: Through reading the Brueggeman interview and looking at your website, I came to know that this paper formed part of your PhD at the University of Washington. What was your motivation to work on intertidal communities for your PhD?
PD: This is independent of the last question. I was already committed to marine ecology and was working with Bob Paine, but my thesis was also much influenced by Gordon Orian’s emphasis on basing ecology on the study of evolutionary processes. I was also influenced by a paper by John Platt about the importance of testing hypotheses, as Paine was doing. But it is hard now for modern ecologists to understand how absolutely dominated ecology was by the dogma that all evolutionary ecology was a result of competition. It was an over-reaction to a long history of density-independent dogma and an ecological focus on using environmental physiology to explain the distribution and abundance of species. But instead of focusing on processes such as predation, facilitation as well as competition, there was an aggressive focus only on competition. This was because the first focus on evolutionary processes was led by charismatic physicists and mathematicians who really did not much care for understanding nature as much as having their models used, and their models were bounded in ways that were not very receptive to predation and facilitation, and many of them went to some effort to downplay the importance of these more realistic processes. I am very dyslexic and was totally unable to understand the beauty of their math, and most models seemed rather irrelevant to the natural world as I perceived it, thinking with pictures as dyslexic people do.
When I first came to graduate school I was diving around Friday Harbor, but the underwater system that I could relate to was already spectacularly studied by Bob Vadas, an excellent student finishing his thesis at the time. So I focused on the intertidal, but focused on some poor questions relating to sea anemones. But in so doing I was also working at sites around Makah Bay where Paine was working. Along with Platt, all of us were much influenced by Joe Connell’s intertidal work, which was very influential in supporting the competition paradigm. But as I crawled around the intertidal habitats of the Washington outer coast and San Juan Islands, I did not see much competition; rather I saw various types of disturbances that ameliorated most potential competition. The potential for space competition was obvious, but many agents that disrupted the competition also seemed common.
Ecology has grown into a discipline of very good, but also very specialized, scientists. Fortunately, I was not influenced by these specialties, and was able to crawl around the very different intertidal systems in the region and try to figure out what processes were at work in each place. And there were all sorts of important factors influencing the patterns. I was most interested in biological questions such as predation, or disturbance such as limpet bulldozing young barnacles and eating small algal recruits, or the facilitation of specific algae that served as nurseries for mussel spat, or refuges from desiccation such as anemones for snails, creating zones of intense snail predation that differed from areas with no anemones. Another form of facilitation was algal overstories sheltering a whole community of small algae. But of course there was some competition, especially in the lower algal dominated levels. But one of the things that is lost by specializing on specific processes, or, importantly, working in a limited number of habitats, is an appreciation of the huge importance of non-biological factors. Every place I worked was physically different, and the differences included the obvious influence of wave exposure and the many critical oceanographic factors determining the recruitment, growth and survivorship of the plants and animals. There were also differences in the rock substrate running from soft sandstone to hard greywacke sandstones to various igneous rock types, and these differences can structure the settlement patterns with all of the subsequent biological interactions. On top of this, in my own areas, the battering by drifting logs was also an important factor. So really, a dyslexic naturalist crawling over this habitat sees all sorts of processes going on at the same time, and the entire spectrum of processes changes from site to site. I did my best to test and describe these processes, missing a lot. The most important lesson for me was that while the habitats are different, the fundamental processes themselves can usually be seen, but they have different ecological strengths from place to place. To really understand the bigger picture, it is good to be able to work in different habitats, to compare the different interactions strengths. But this personal appreciation for seeing the big picture is why I think that those non-naturalists focusing on their statistical dogmas have done so much damage to a general understanding of natural systems. I would say the same thing about those working only with models or in the laboratory. Surly appropriate statistics, models and laboratory research can be extremely valuable, but only when they are tied into real natural history.
Sorry for the long rant responding to a simple question!
Dog dish experiments excluding limpets (lower left), normal density (top) and 2x density (lower right) (© Paul Dayton)
HS: If you don’t mind my asking, how come your PhD supervisor – Robert Paine – wasn’t an author on this paper?
PD: I don’t mind your asking, but really I think you should unask the question and instead ask why is it that most ecologists slap their names on anything they can, including their students research. In those days none of the good ecologists put their names on their students’ papers. I don’t think Paine ever put his name on a student’s paper, nor do I remember Joe Connell doing so, nor Thorson nor Kitching or any good ecologists of the era. I did not do so either. Joint authorships were done when you genuinely worked together on a project, and I put Paine on some of my early Antarctic papers as he contributed a lot. So the real question is why it is so common now, and the obvious answer is that our “fame” seems to depend on number of papers and citations rather than the creative breakthroughs or important advances to a field. I like to think that the colleagues I care about are able to evaluate my “worth” based on, both, publications and independent students not dragging my name around as a “Matthew Effect!” The problem is that our bureaucrats are too lazy to do their jobs well, and want to be dazzled by metrics such as numbers of papers irrespective of whether the papers say anything worth while or those stupid H values that reflect nothing of much importance that I can see. And nobody any more keeps track of successful students we mentor, and here is where I want to stake my legacy.
HS: Do you continue to visit and work in the sites that you sampled during this study?
PD: I so wish I had done so. I always wanted to but only got back a couple times. I offer the normal excuses: I was busy with other time-consuming projects, mentoring wonderful students who really mentored me, and I was totally committed to spending my summers camping with my kids until they got into high school.
HS: Would you remember how long the writing of this paper took and where you did most of the writing? Apart from your supervisor, Robert Paine, were there other people who you were regularly discussing your work with at the time?
PD: Good question. I got a tremendous amount of mentoring by Bob Paine, Joe Connell, and Bob Fernald, but most of my real learning came at the hands of graduate students. Graduate students shared large offices and most of us did our writing at home. I wrote it all by hand, as I write badly and it needed lots of smoothing. My cohort of graduate students, especially Rick Vance, Bruce Menge, Chuck Birkeland and Sally Woodin broke their butts trying to teach me math and theory – that they failed is no fault of their own as I now understand the severity of my dyslexia. In the end, my good wife did all of the statistics in the paper, and helped with my prose. I finally sat in the kitchen and painfully typed all of the piles of scribbles, and my committee did an excellent job reading it and helping me make it literate! But it did not really take very long, as I had thought about it a lot and knew pretty much what I wanted to say. I think I started writing in February and was mostly finished in early summer.
HS: How were the figures in the paper drawn?
PD: By hand! In those days we had sets of frames that we used to draw lines, curves and letters, but they were all carefully traced by hand.
HS: Could you give us a sense of what your daily routine was during the fieldwork for this study? Did you mostly work alone or did you have people to help you?
PD: Entirely alone. I worked in two areas that were several hours from Seattle, where I had to return to teach labs for my salary until the end. It is documented in my thesis, but I think I was in the field over 60% of the 5 years I was in graduate school. The outer coast sites were rainy and difficult to get to, but very rewarding and fascinating for their high diversity and all of the fascinating interactions. The tides were often in the middle of the night, and I spent the day fishing for Salmon from Bob Paine’s tiny boat. I slept and ate in my small 4-wheel drive vehicle. The San Juan Island sites were much dryer and more difficult to work because the rock was so hard. I struggled to maintain the cages. But there I had the luxury of a house to stay in and I was better able to work up data and get caught up. I spent my free time solo diving, looking at sea star foraging biology. At the time, I think I was stressed trying to keep up with all the driving and fieldwork and keeping up with the data, but in hindsight those were absolutely the best times of my life. Bob Paine was a wonderful warm friend as well as a mentor and he kept reminding me how lucky I was, and he sure was right.
Eagle Point Study site, San Juan Island, Washington, and the old International Scout Paul Dayton, mostly, lived in. Dayton says that this area is, today, totally blocked by huge mansions and not accessible for scientific study (© Paul Dayton)
HS: Did this paper have a relatively smooth ride through peer-review? Was Ecological Monographs the firs place this was submitted to?
PD: Yes and Yes! I marked up the actual thesis very carefully, in the first month of my job, the generous Department secretary retyped it, and I submitted it within a few months of defending the thesis. The reviewers were Peter Franks and Joe Connell and both were very careful and constructive and helped me in many ways, but it went right through. I don’t know who reviewed the 1972 Postelsia, 1973 right-for-the-wrong-reason and 1975 algal papers, but they were all very constructive and I did not have the nightmare that many young students experience now. The people in Paine’s generation were very constructive and helpful, but unfortunately those of my generation seem hyper-critical and often hostile. I very much regret this situation.
HS: Could you give us a sense of what kind of impact this paper had on your career and on the future course of your research?
PD: The Ecological Society of America recognized it with their Mercer Award, which meant a lot to me. In the beginning, it did not have much effect on my career and I am not sure it influenced my tenure promotion. By that time, I had published several pretty good papers from the inter-tidal, the Antarctic and the kelp system. I would expect that the Mercer Award helped with the promotion, but I don’t think many people have actually read the 1971 paper, even though it is heavily cited.
HS: Today, 45 years after it was published, would you say that the main conclusions of this paper are still true, more-or-less?
HS: Yes. Even without the reasonable caveat of putting it back to the state of the science then, I immodestly think that the conclusions are pretty much true today.
HS: If you were to redo this study today would you do anything differently?
PD: I would write it very differently. It is heavily cited but not read. People cite and recycle something apparently without realizing what I had done. Sometimes this is reader laziness, but in this case there is no doubt that the paper is very hard to read. That is entirely my fault. I still struggle with my prose, but I dearly wish I had struggled a lot harder with that paper, perhaps breaking it into several papers.
The other thing I would emphatically do differently is bring in all the different strengths of the processes as one goes across this huge environmental gradient from Tatoosh Island to Colin’s Cove. I was so entrained into the battle with the competition folks that I focused too narrowly on my message, that in the real world nature is much more influenced by disturbance than resource competition. I drove thousands of miles working the two areas at the same time and really completely failed to discuss the obvious lessons about the physical effects of the shifting environmental conditions across that gradient.
HS: You say “The most important physical factors correlated with differences in the relative distributions and abundances of the important sessile species in the intertidal are (1) wave exposure, (2) battering by drift logs, and (3) physiological stresses such as desiccation and heat”. Today, do these three factors continue to be the most important?
PD: If I said that it represents another terrible omission. Most of the focus of the paper and my career is on the various evolutionary roles of biological interactions: competition for potentially limited resources, predation, disturbance, and facilitative interactions. Certainly those three factors are critically important, but I would also add biological interactions!
HS: This paper is today a ‘citation classic’. At the time when you were doing your work did you anticipate at all that it would have such a big impact on the field? Would you know what the paper mostly gets cited for, i.e. is it cited appropriately most of the time?
PD: I was young and insecure and I hoped all marine ecologists would read it and agree with the idea that disturbance trumps competition in most systems. It took awhile, but eventually I think that the message did get across. I think that most of the citations I have seen are appropriate and I am very grateful that my peers recognize it. I think my colleagues are very generous with their citations and I am grateful.
HS: Have you ever read this paper after it was published? When you compare this paper to ones you write today do you see any striking differences?
PD: Not really: it is hard for me to read also! Once in a while, I go back and dig something out to remind myself what I did. Surely, it would never even be reviewed now because of its length. This is probably a good thing because it would be more readable, yet I have always enjoyed my “story telling” approach to ecology, that involves an understanding of the big picture in time and space. Even as a student I realized how important scaling time and space were, and that would be lost if the paper were to be chopped up as demanded by today’s standards.
HS: Would you count this as one of your favorites, among all the papers you have published?
PD: I am very proud of the paper and grateful for the recognition. And I am still proud of the total thesis, although I don’t think it was as good as the one Bob Vadas did before me. Students then were doing interesting projects and I think that there were many good theses. Frankly, I am more proud of a couple of my kelp papers, and the one I am most proud of was done in the Antarctic at the same time I was doing my thesis. This was published in 1974, and the reason I am proud of it is that it was done in two brief and difficult field seasons, but we had to reject the entire research paradigm that we based the project on to start with. We had to switch questions in the field and focused on asteroids and sponges, and in the second season none of our experiments had worked because we totally underestimated the slow growth rates. At that point, I had to find a way to estimate the predation rates and consumptions over a year. This was done using the ecosystem approaches of the era that I did not know and had to learn in the field in Antarctica. Bob Paine visited us there, and was very helpful as we struggled to estimate the effects of the predators on the sponge populations. These days, ecosystem and population people rarely interact, and have developed very different specialties, but being able to synthesize both approaches made that paper possible.
HS: What would you say to a student who is about to read this paper today? What should he or she take away from this paper written 45 years ago?
PD: I would tell her that this paper is very difficult to read, but it has a lot of interesting information that might be useful to her. I would explain the value of story telling as a means of understanding nature, and that there are several interesting stories in the paper. I would suggest that as she reads it she copies the table of contents and lists the various vignettes or stories in the paper, and at the end see if she can synthesize those that are of interest to her into a big pictures story that makes sense.
HS: Thanks so much!
PD: My pleasure, sincerely. Thanks for including me in your project. I just did this at home and realize it is more complete than I would have done in an interview because I had to write it in short bits of times getting the grandkids ready for their sabbatical! But I kept thinking that if there is anybody interested enough in the paper or in me, that there are a lot of fun stories in the oral history I did with Peter Brueggeman. The dynamite story comes to mind as something that is simply not conceivable today and people find it amusing. If it is possible I suggest that you send them to Peter’s web site to read it if they are interested.
Paul Dayton in Portage Head, study site, Olympic Peninsula, Washington (© Linnea Dayton).