Category Archives: History of Ecology

Some Reflections on Evo-Eco

Some ecologists study evolutionary processes and we call them evolutionary ecologists. They have their own journals and are a thriving field of science. Other ecologists study populations, communities, and ecosystems in ecological time and do not in general concern themselves with evolutionary changes.The question is should they? Evo-Eco is a search for evolutionary changes that have a decisive impact on observable ecological changes like that of a collapsing bird population.

There are two schools of thought. The first is that evo-eco is very important and the changes that ecologists are trying to understand are partly caused by ecological mechanisms like predation and competition but are also associated with genetic changes that affect survival and reproduction. Consequently an ecologist studying the declining bird population should study both genetics and ecology. The second school of thought is that evo-eco is rarely of any importance in causing ecological changes, so that we can more or less ignore genetics if we wish to understand why this bird population is disappearing.

A practical problem immediately rears its head. To be safe we should all follow evo-eco in case genetics is involved in dynamics. But given the number of problems that ecologists face, the number of scientists available to analyse them, and the research dollars available it is rare to have the time, energy or money to take the comprehensive route. Conservation ecologists are perhaps the most tightly squeezed of all ecologists because they have no time to spare. Environmental managers request answers about what to do, and the immediate causes of conservation problems are (as everyone knows) habitat loss, introduced pests and diseases, and pollution.

The consequence of all this is that the two schools of thought drift apart. I cannot foresee any easy way to solve this issue. Progress in evolutionary ecology is often very slow and knowing the past rarely gives us much insight into predicting the human-affected future. Progress in conventional ecology is faster but our understanding is based on short-term studies of unknown generality for future events. Both schools of thought race along with mathematical models that may or may not tell us anything about the real world, but are conceptually elegant and in a pinch might be called progress if we had time to test them adequately.

The most useful evo-eco approach has been to look at human-caused selection via fishing for large sized fish or hunting for Dall sheep with the largest horns. The overuse of antibiotics for human sickness and as prophylactics for our farm animals is another classic case in which to understand the ecological dynamics we need to know the evolutionary changes that we humans have caused. These are clear cases in which genetic insights can teach us very much.

I end with a story from my past. In the 1950s, nearly 70 years ago now, Dennis Chitty working at Oxford on population fluctuations in small grassland rodents considered that he could reject most of the conventional explanations for animal population changes, and he suggested that individuals might change in quality with population density. This change he thought might involve genetic selection for traits that were favourable only in high density populations that reappeared every 3-4 years. So in some strange sense he was one of the earliest evo-eco ecologists. The result was that he was nearly laughed out of Oxford by the geneticists in control. The great evolutionary geneticist E.B. Ford told Chitty he was completely mad to think that short term selection was possible on a scale to impact population dynamics. Genetic changes took dozens to hundreds of years at the best of time. There were of course in the 1950s only the most primitive of genetic methods available for mammals that all look the same in their coat colour, and the idea that changes in animal behaviour involving territoriality might cause genetic shifts on a short-term period gradually lost favour. Few now think that Chitty was right in being evo-eco, but in some sense he was ahead of his time in thinking that natural selection might operate quickly in field populations. Given the many physiological and behavioural changes that can occur phenotypically in mammals, most subsequent work on grassland rodents has become buried in mechanisms that do not change because of genetic selection.

When we try to sort out whether to be concerned about evo-eco, we must strike a compromise between what the exact question is that we are trying to investigate, and how we can best construct a decision tree that can operate in real time with results that are useful for the research question. Not every ecological problem can be solved by sequencing the study organism.

Chitty, D. 1960. Population processes in the vole and their relevance to general theory. Canadian Journal of Zoology 38:99-113.

On Important Questions in Ecology

There is a most interesting paper that you should read about the important questions in ecology:

Sutherland, W.J. et al. (2013) Identification of 100 fundamental ecological questions. Journal of Ecology, 101, 58-67.

This paper represents the views of 388 ecologists who culled through all of the 754 questions submitted and vetted in a two day workshop in London in April 2012. There are many thesis topics highlighted in this list and it gives a good overview of what many ecologists think is important. But there are some problems with this approach that you might wish to consider after you read this paper.

We can begin with a relatively trivial point. The title indicates that it will discuss ‘fundamental’ questions in ecology but the Summary changes this to ‘important’ questions. To be sure the authors recognize that what we now think is ‘important’ may be judged in the future to be less than important, so in a sense they recognize this problem. ‘Important’ is not an operational word in science, and consequently it is always a focus for endless argument. But let us not get involved with semantics and look at the actual 100 questions.

As I read the paper I was reminded of the discussion in Peters (1991, p. 13) who had the audacity to point out that academic ecologists thrived on unanswerable questions. In particular Peters (1991) focused on ‘why’ questions as being high on the list of unanswerable ones, and it is good to see that there are only 2 questions out of 100 that have a ‘why’ in them. Most of the questions posed are ‘how’ questions (about 65 instances) and ‘what’ questions (about 52 instances).

In framing questions in any science there is a fine line in the continuum of very broad questions that define an agenda and at the other extreme to very specific questions about one species or community. With very broad questions there will never be a clear point at which we can say that we have answered that question so we can move on. With very specific questions we can answer them experimentally and move on. So where do we cut the cake of questions? Most of these 100 questions are very broad and so they both illuminate and frustrate me because they cannot be answered without making them more specific.

Let me go over just one example. Question 11 What are the evolutionary and ecological mechanisms that govern species’ range margins? First, we might note that this question goes back at least 138 years to Alfred Wallace (1876, The Geographical Distribution of Animals), and has been repeated in many ecology textbooks ever since. There are few organisms for which it has been answered and very much speculation about it. At the moment the ecological mechanism in favour is ‘climate’. This is a question that can be answered ecologically only for particular species, and cannot be answered in real (human) time for the evolutionary mechanisms. Consequently it is an area rife for correlational ecology whose conclusions could possibly be tested in a hundred years if not longer. All of these problems should not stand in the way of doing studies on range margins, and there are many hundreds of papers that attest to this conclusion. My question is when will we know that we have answered this question, and my answer is never. We can in some cases use paleoecology to get at these issues, and then extrapolate that the future will be like the past, a most dubious assumption. My concern is that if we have not answered this question in 138 years, what is the hope that we will answer it now?

It is good to be optimistic about the future development of ecological science. Perhaps I have picked a poor example from the list of 100 questions, and my concern is that in this case at least this is not a question that I would suggest to a new PhD student. Still I am glad to have this list set out so clearly and perhaps the next step would be to write a synthesis paper on each of the 100 topics and discuss how much progress has been made on that particular issue, and what exactly we might do to answer the question more rapidly. How can we avoid in ecology what Cox (2007) called a “yawning abyss of vacuous generalities”?

Cox, D. R. (2007) Applied statistics: A review. Annals of Applied Statistics, 1, 1-16.

Peters, R. H. (1991) A Critique for Ecology, Cambridge University Press, Cambridge, England.

Sutherland, W. J., Freckleton, R. P., Godfray, H. C. J., Beissinger, S. R., Benton, T., Cameron, D. D., Carmel, Y., Coomes, D. A., Coulson, T., Emmerson, M. C., Hails, R. S., Hays, G. C., Hodgson, D. J., Hutchings, M. J., Johnson, D., Jones, J. P. G., Keeling, M. J., Kokko, H., Kunin, W. E. & Lambin, X. (2013) Identification of 100 fundamental ecological questions. Journal of Ecology, 101, 58-67.

On Charles Elton

Charles Elton was the Father of Animal Ecology and many young ecologists do not learn very much about him. He founded the Bureau of Animal Population at Oxford in 1932, and much of the history of his research group is captured in Peter Crowcroft’s book “Elton’s Ecologists” (1991). I was fortunate to spend the winter of 1960-61 at the Bureau while I was completing my Ph.D. at UBC with Dennis Chitty. It was Dennis’ last year at the Bureau, having gone there in 1935 when he had just finished his undergraduate work at the University of Toronto.

The Bureau of Animal Population or BAP, as all connected with it came to call it, had been born in January 1932 and by 1934 Oxford University had guaranteed funds for its core costs for five years with 3-4 scientific staff and a very few assistants. Survival as a unit depended on working on numerous applied projects, and the species receiving attention included Canadian snowshoe hares, Canadian lynx, muskrat, beaver, lemmings, European rabbits, squirrels, voles and the wood mouse. The Bureau was the home of the newly created Journal of Animal Ecology, of which Charles Elton was the first editor.

Charles Elton was a proper English gentleman, a gentle soul who had a coterie of first class ecologists in the BAP. The BAP was very nearly the world centre for ecology from the 1930s to the 1960s when ecology began its great growth around the world, so everyone who was interested in population ecology considered it equivalent to Mecca for science. Every day there was tea in the BAP in 1960, when we all took time to interact with the other postdocs and graduate students in the BAP, a total group of perhaps 15-20. Once a week Mr. Elton (as he never did a Ph.D.) would preside over tea around a table in the BAP Library and give out any news of the week to the staff and students. On most days he wore a tie and a sport coat in the best English tradition, and signed his letters as “Elton”. In 1960 he was compiling a species list for Wytham Woods, a 390 ha forest reserve belonging to the University. He felt strongly that one had to know all the species in a community before you could understand how it operated. So one could see him day after day pinning insects in trays. He was always very serious, and the only joke I ever heard him tell was about how he could never understand Americans. He had gone to the New World after the War, perhaps 1947 or 1948 and was visiting a famous American scientist. They had to get up at 0700 in the morning and rush to work without a proper English breakfast, and so at 0800 they arrived in the professor’s office, and then Elton said he was told ‘now you can relax’. It was not the proper English way to start the day and he could never understand the rush-rush style of the New World.

Charles Elton founded the Journal of Animal Ecology in 1931, now one of our leading journals. In the early days he did much of the reviewing and accepting of papers for the Journal. He had an amusing tale of the classic papers of A.J. Nicholson (1933) on the balance of animal populations. He received this very long paper and he could not find anyone who would agree to review it so he did it himself. He confessed to us one day at tea that he found he could not understand anything in the paper, so he decided it must be very brilliant so he published it immediately. Alas those days are gone.

There were of course no electronic machines even in 1960 and Elton did all his writing by pen and paper. He had just finished the now famous book “The Ecology of Invasions” and his secretary who typed all his work pointed out to me that he never changed a word from what he first wrote. No need for revisions and revisions. He was of course like a god to all of us young ecologists, and so we were very fortunate that this was the year in which he was teaching his Animal Ecology course to Oxford undergraduates. All of us graduate students and postdocs went along, as it was only a series of 14 lectures in the best Oxford tradition. The classroom was full in the first lecture, which was one of the worst lectures I have ever attended. We were rather stunned that such a great man could lecture so hopelessly, mumbling in a monotone, showing slides but almost never referring to them, every mistake in the book. We realized then that greatness could occur in many dimensions and his skill was as a writer. Classroom attendance fell like an exponential and by the fifth lecture no one was left in the classroom but we of the BAP.

Elton organized the BAP as a small research unit and did not believe that any research unit should exceed more than a handful of scientists who interacted all the time over a small subset of problems. In the early days much of the research was on cyclic populations of rodents and fur bearers in Europe and North America, but it moved to insects and broader problems after the War.

Oxford was a strange place to a North American in 1960. Too many of the professors were at odds with one another, jostling for fame we all presumed. It was impossible not to have many enemies within and outside the walls of Oxford, and we as students never quite knew why some were praised and others reviled. Perhaps ideas were confounded with personalities, and no one thought that you could respect a scientist but disagree with his or her view of science. But much was at stake then, and when you were King of Oxford you were king of the hill. Now 50 years later we have many kings of science all around the world, and I hope that Oxford has changed.

 

Crowcroft, P. 1991. Elton’s Ecologists: A History of the Bureau of Animal Population. University of Chicago Press, Chicago. 177 pp.

Elton, C. S. 1958. The Ecology of Invasions by Animals and Plants. Methuen, London. 181 pp.

Nicholson, A. J. 1933. The balance of animal populations. Journal of Animal Ecology 2:132-178.