Author Archives: Charles Krebs

How to Run a Successful Scientific Conference

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Over the last 50 years I have attended about 200 ecological conferences. The best meetings have followed a series of practices that I present here. This list can be viewed as a practical example of adaptive management, since conferences that score low on the scale of suggestions here have in my opinion been less successful. Two major items drive a conference – papers and posters. Three other items are critical – good food, a spacious venue, and well organized symposia, but I will not discuss these three here.

Papers are presented at conferences largely as powerpoint talks. Most of these talks are 15 or 20 minutes but the rules for good powerpoint talks are quite simple.

  • A good slide in Powerpoint makes no more than 2 or 3 points, and these points should augment, emphasize, and explain the speaker’s words.
  • For complicated subject matter, use 2 or 3 simple figures rather than one complex, cluttered and unclear figure.  A series of slides that build on each other is very effective.
  • Effective labels for slides are briefer and larger than those for publication.  Titles should be 40-44 point font (14 mm) and text 32 point (11 mm).  Bold and italic labelling should be saved for special emphasis. 
  • Slide titles should be relatively short – 1 line only.
  • If using colour, stick to primary, bright, and clear colours.  
  • Do not use a photo as a background for the slide. It may be good artistically but it distracts from the points you are making.
  • Word slides should contain no more than 5 short statements.  The information on the slide should be simplified to the point of being skeletal.  It is up to the presenter to fill in gaps.  You should never have more than 30 words on a slide. 20 would be better.
  • Presenters should not read word slides to the audience.  The audience can read the slide faster than the presenter can speak it.
  • If all the information on a slide is not valuable to the audience, leave it out.  Take the time to adapt figures or tables for your presentation.
  • A good average is one slide per minute of talk.  If you have more, you are going too fast for the audience.
  • If people remember your presentation, they will remember only one or two key points. Summarize these at the end of your talk.
  • Never never never put 2 or 3 graphs or photos on a powerpoint slide since no one will be able to read the labels.
  • Look at your powerpoints in a bright room and in a dark room and see if you can still read them. You will not know how the conference lighting will be arranged.
  • Go to the back of the room and look at your Powerpoint presentation. If you need binoculars to read the slides, go back to step 1.

So if you are giving a 15 minute talk at the next conference you attend, prepare 15 slides in powerpoint. If you are giving a 3 minute speed talk, never have more than 3 slides. Simple arithmetic.

Posters are the next most important communication device used in scientific conferences, and unfortunately posters are typically awful as they are usually constructed with far too much detail. Here are a few rules for posters.

  • Focus on 3 points or less. If you can get across even 1 point clearly and quickly to your viewer, your poster is successful. Remember that you will be there to answer questions and fill in details.
  • Lengthy poster titles discourage viewers! Titles should be brief, informative, and interesting.
  • Text should be readable without strain from 1 m. Height of TITLE text should be about 100 point (3 cm) and height of BODY TEXT should be about 30 point (0.8 cm). Figure labels should be a minimum of 24 point (8 mm). See if you can read it from 1 m distance.
  • Use simple fonts such as Arial, Helvetica, or Univers. These are proportionately spaced and conventionally shaped so will not distract from the information they describe.
  • Avoid abbreviations and jargon. Avoid all but the simplest tables. No one will read a table with 10 columns and 25 rows.
  • Because all graphs should be large, information on graphs should be limited, and labels should be short. Specify measurement units. Provide scales on maps.
  • Plan the poster to be read in sections from left to right and top to bottom. Each section should be easily read while standing in one spot.
  • Colour keys used consistently throughout the poster make information easier to follow.
  • Avoid using photographs as a background for text or figures.
  • If your poster has more than 300-400 words, you have too much detail.
  • Give an executive summary or abstract of 50 words or less at the start of the poster. What is the question or problem, and what have you achieved in answering it?
  • Put a small, clear photo of yourself on the top right of the poster so people will recognize you.
  • Provide copies of a one-page printed summary of your poster for viewers who are interested in more detailed information or do not have time to read it, and give your contact information on this page.
  • Images should ideally be scanned at the size that they are to be used on the poster (not scanned and then dragged to the appropriate size). Most poster printers can’t process higher than 300dpi, so there’s no point scanning at a resolution higher than this.
  • Look at your poster in a bright room and see if it is readable under bright light conditions.

 

Experimental Model Systems in Ecology

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Ecology progresses slowly when we have to study natural populations or communities. It is expensive to manipulate large units of habitat, and there are two approaches that suggest themselves to alleviate this problem. First, study small areas that can be analysed and manipulated by one or two persons. This can be a useful approach, depending on your question and hypotheses, and I do not discuss this approach here. The second approach is through experimental model systems. Typically this means taking the question or problem into a semi-laboratory system. For aquatic studies it may mean putting large cylinders in a lake (Carpenter 1996). For rodent studies it may mean putting populations into small fenced enclosures. For sake of clarity I will discuss this latter example with which I am familiar.

The key question for all experimental model systems in ecology is to know at what spatial and temporal scale the system works. To gain precision we typically want to conduct our studies within an enclosure of some small size. That is, we wish to study an open system with more precision by converting it to a closed system of some much smaller size. But what size allows the system to operate as an open natural population, in this example of rodents? In a sense we wish to know the shape of this generalized curve:

EMS_Drawing1

Assume there is some natural outcome known for the particular study. In the case of small rodents this might be that the population fluctuates in periodic ‘cycles’. The question then is what size of enclosure is needed to observe this same population trend. One simple way of looking at this is to ask for islands, what size of island allows a closed population to fluctuate in ‘cycles’. For this particular problem we know that you cannot observe ‘cycles’ in small rooms in the laboratory or even in 1 ha field enclosures.

Many other examples can be given for this type of question in ecology. For example, we may know that infanticide in a particular species is rare in natural populations. But if we raise the same species in small cages in the laboratory, we may observe infanticide very commonly. We would conclude that this is not the natural state of this system, and thus decide that you could not draw conclusions about the frequency of infanticide by studying it in small cages.

The critical judgement is whether any experimental model system we design will mimic natural processes that occur in open, real world populations or communities. All too often in ecological studies we assume that the size of the enclosure or study area that we are using is “natural” and the conclusions will represent what happens in natural populations or communities. In an ideal world we would examine a series of sizes of our study enclosures to see the best one that mimics natural outcomes. But this cannot always be done for reasons of time and money. In some cases we have no idea what the natural situation is, and in these cases it is most difficult to know if our model system results bear any relationship to reality.

This whole issue is another way of looking at the problem of habitat fragmentation – how small a piece of habitat can we get by with to conserve species X or community Y? These types of conservation questions always involve a temporal as well as a spatial dimension, given the problem of extinction debts (Krauss et al. 2010). In the extreme case we can argue that we can conserve at least some species in zoos, but this is a way of avoiding the main goal of conserving natural environments and processes.

The bottom line is to ask yourself as you are setting up a study using an experimental model system approach whether the process you are investigating can be observed at the spatial and temporal scale you have available. Alternatively it may be important to try to construct the curve shown above for the system of interest. This question is important because some previous studies for any ecological system may have reached invalid conclusions because of a faulty spatial scale of the model system.

Carpenter, S. R. 1996. Microcosm experiments have limited relevance for community and ecosystem ecology. Ecology 77:677-680.

Krauss, J., R. Bommarco, M. Guardiola, R. K. Heikkinen, A. Helm, M. Kuussaari, R. Lindborg, E. Öckinger, M. Pärtel, J. Pino, J. Pöyry, K. M. Raatikainen, A. Sang, C. Stefanescu, T. Teder, M. Zobel, and I. Steffan-Dewenter. 2010. Habitat fragmentation causes immediate and time-delayed biodiversity loss at different trophic levels. Ecology Letters 13:597-605.

In Defence of Hypothesis Testing in Ecology

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In two recent scientific meetings I have attended (which must remain nameless to protect the innocent), I have found myself wondering about the state of hypothesis testing in ecological science. I have always assumed that science consists of testing hypotheses, yet I would estimate roughly that 75% of the talks I have been able to attend showed no sign of any hypothesis. I need to qualify that. Some of these studies are completely descriptive – what species of ferns occur in national park X? Much effort now is devoted to sequencing genomes, the ultimate in descriptive biology. This kind of research work can be classified as alpha-biology, basic description which is necessary before any problems can be formulated. In my particular specialty of population cycles in mammals, much descriptive work had to be carried out to recognize the phenomenon of “cycles”. But then the question arises – at what point should we stop simple descriptions of mammal populations rising and falling? Do we need to study the dynamics of every rodent species that exists? Or in genetics, is our objective to sequence the genome of every species on earth? My point is that after we have enough basic description, we should move into hypothesis testing, or asking why some phenomenon occurs, the mechanisms behind the simple observations. The important point here is that we should not have a single hypothesis or explanation for any set of observations but rather several alternative hypotheses. As a simple example, if we find our favourite plant species is declining in abundance, we should not simply try to connect this decline with climatic warming without having a series of alternative explanations with the emphasis that our observations or experiments should be capable of distinguishing among the alternative hypotheses.

The alternative argument is that we do not know enough about ecological systems to set up a series of credible alternative hypotheses. It is quite possible to go on describing events endlessly in science in the hope that some wisdom will emerge. I do not think this is a profitable use of time or money in science. In ecology in particular I would argue that there is not a single question one can ask that cannot be answered by at least 2 or 3 different mechanistic hypotheses. Our job is to articulate these alternatives and to do whatever studies or experiments are needed to distinguish among them. Of course it is always possible that the correct answer is not among the 2 or 3 hypotheses we suggest at the start of an investigation, and this is often why one study leads to a further one. Consequently we cannot accept statements like “I have no idea why this observation has occurred”. Such a statement means you have not thought deeply enough about what you are studying. Ecological surprises certainly occur while we study any particular community or ecosystem, but we know enough now to suggest several possible mechanisms by which any ecological surprise might be generated.

So I think it incumbent on every ecologist to ask (1) what is the problem or question my research is addressing? And (2) what probable mechanisms can be invoked as the cause of this problem or the answer to this question. Vagueness may be a virtue in politics but it is not a virtue in science. And I look forward to future conferences in which every paper specifies a precise hypothesis and alternative hypotheses. Chamberlin (1897) stated the case for multiple hypotheses, Karl Popper (1963) asked very specifically what your hypothesis forbids from happening, and John Platt (1964) pulled it together in a critical paper. There was important work done before the Iphone was invented. Good reading.

Chamberlin, T. C. 1897. The method of multiple working hypotheses. Journal of Geology 5:837-848 (reprinted in Science 148: 754-759 in 1965).

Platt, J. R. 1964. Strong inference. Science 146:347-353.

Popper, K. R. 1963. Conjectures and Refutations: The Growth of Scientific Knowledge. Routledge and Kegan Paul, London.

The New Conservation?

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In a recent book “Love Your Monsters: Postenvironmentalism and the Anthropocene” edited by Mihael Shellenberger and Ted Nordhaus (Breakthrough Institute, 2011) Peter Kareiva, Robert Lalasz, and Michel Le Marvier present a vision for conservation in a paper: “Conservation in the Anthropocene: Beyond solitude and fragility” that bears some analysis. It is available on the Breakthrough Institute website. It is a rather misleading vision, like many visions, partly correct, partly wildly inaccurate, and partly tilting at dragons that do not exist.

In general any subject that ranges out from science into policy starts to walk on thin ice when opinions masquerade as scientific information. A few quotes can give you the flavor of this article. “By its own measures, conservation is failing. Biodiversity on Earth continues its rapid decline”. A strong statement but how has anyone decided that conservation is failing? If the evidence is that biodiversity in some groups and some places is being lost, then any ecologist can agree. If conservation is failing, then we might expect some guidance of how to prevent this failure.

The next quote grabs the issue directly: “Conservation cannot promise a return to pristine, prehuman landscapes. Humankind has already profoundly transformed the planet and will continue to do so.” I know quite a few conservation biologists and I can not think of one who would disagree with this statement. There could be some who are promising a return to pristine landscapes, but they must be rare, as are those that still think the earth is flat. So here is Straw Man # 1. (This is not sexist by the way, no female conservation biologist would make such a silly Straw Person.) So let us proceed by agreeing that we cannot go back to pristine nature, and humans are indeed having a large effect on the Earth.

Now we are getting into the center of the proposal with this quote: “But conservation will be controversial as long as it remains so narrowly focused on the creation of parks and protected areas, and insists, often unfairly, that local people cannot be trusted to care for their land.” Alas this is hardly what most conservation biology focuses on. So we might call this Straw Man # 2. The goal of most conservation is to protect biodiversity in all its forms, in parks, in nature reserves, in agricultural fields, in forest woodlots, and in cities. I cannot comment on situations in which local people are adversely affected by conservation activities. In the few cases I know the local people are happy to cooperate in conservation programs, but I can imagine there are conflicts I am not acquainted with. So can we agree that conservation is NOT narrowly focused on parks? Parks and reserves are part of the conservation picture but far from all of it.

The reason conservation biologists have adopted this narrow agenda is captured in the next quotation: “But ecologists and conservationists have grossly overstated the fragility of nature, frequently arguing that once an ecosystem is altered, it is gone forever. Some ecologists suggest that if a single species is lost, a whole ecosystem will be in danger of collapse, and that if too much biodiversity is lost, spaceship Earth will start to come apart.” Now I have to start looking under the carpet to find such an ecologist. Really this is quite silly, and an insult to current ecological knowledge. As a reductio ad absurdum this is a prize quotation and we can call it Straw Man # 3. I have no doubt that we could find someone on earth who would say this, but that is hardly evidence that ecologists agree on such nonsense. That it is nonsense of course is no argument that one can keep removing species from ecosystems with no consequences whatsoever.

We now come back to a more modest quote: “The trouble for conservation is that the data simply do not support the idea of a fragile nature at risk of collapse. Ecologists now know that the disappearance of one species does not necessarily lead to the extinction of any others, much less all others in the same ecosystem. In many circumstances, the demise of formerly abundant species can be inconsequential to ecosystem function.” Since no ecologist supports the thesis of the previous paragraph, we can certainly agree with this quotation, so perhaps we are back on track.

The next quote however puts us back into the perceived picture: “Nature is so resilient that it can recover rapidly from even the most powerful human disturbances…. Even that classic symbol of fragility — the polar bear, seemingly stranded on a melting ice block — may have a good chance of surviving global warming if the changing environment continues to increase the populations and northern ranges of harbor seals and harp seals.” Alas we are back to serious nonsense again. The literature on restoration ecology is one long litany of rejections of the idea of resilient recovery from human disturbance. It simply does not occur except perhaps on a time scale that is geological. And polar bear biologists do not think they will go extinct at least in the next 100 years that we can project. So here is STRAW MAN # 4 (or perhaps straw bear?).

We are now led to the final conclusion: “If there is no wilderness, if nature is resilient rather than fragile, and if people are actually part of nature and not the original sinners who caused our banishment from Eden, what should be the new vision for conservation? Instead of pursuing the protection of biodiversity for biodiversity’s sake, a new conservation should seek to enhance those natural systems that benefit the widest number of people, especially the poor. Instead of trying to restore remote iconic landscapes to pre-European conditions, conservation will measure its achievement in large part by its relevance to people, including city dwellers… Conservation is slowly turning toward these directions but far too slowly and with insufficient commitment to make them the conservation work of the 21st century. The problem lies in our reluctance, and the reluctance of many of conservation’s wealthy supporters, to shed the old paradigms.”

If the first two premises in this last quotation are highly questionable, and the third is and has been agreed by all conservation biologists for many years, how do we get to the conclusions given the questionable premises? While it sounds exciting to shed the old paradigms, we have to be careful rather to take the valid points from all our approaches, and try to correct the failings of conservation science. As in much of ecological science, the truism that “the devil is in the details” applies with much force to conservation issues, and there is no one path to glory.

 

 

 

In Praise of Luddites

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We are certainly in the midst of a new era of luddites but instead of the original concept of a person opposed to technology that would reduce jobs, we now have luddites in politics opposed to scientific information. Not that this is terribly new historically but it seems to be part of a new conservative government agenda. The operating principle of the new luddites is quite simple: what you do not know cannot hurt you. This principle is illustrated every day by a person typing a text message as they walk across a busy road intersection, but it has now been adopted by several governments in western countries. The politicians involved of course would never recognize themselves as luddites but would argue that they are responsible spenders of the taxpayers money. When a large government agency faces a budget cut, what is more responsible than to cut out people who do the environmental work. Close down scientific research stations. Reduce funding for environmental monitoring. Eliminate the need for environmental impact studies. After all what environmental scientist of recent time has ever given good news to the government or indeed done anything to increase GNP. Since environmental problems are large-scale, long-term issues, they need not be dealt with today or even in the next 6 months. The result is that today we are locked in an arms race with environmental scientists arguing that we should do something now about climate change, species under threat, or other ecological problems, and the political world arguing that we can deal with these issues later after we increase economic growth. Since a large part of the research effort that explores environmental trends comes from the government, a simple way to turn down the thermostat is to reduce funding to environmental science and to prevent government scientists from talking to the public.

We awake only when there is an environmental disaster that cannot be covered up. This is a bit like thinking about getting fire insurance once you realize your house is on fire, not exactly forward planning. So we too often continue down the path of the luddite, with elections being fought over the economy with barely a mention of the environment. At a meeting of first nations people recently the opening statement was that we are responsible for the next 7 generations following us, the grandchildren of our grandchildren. What politician could say this with a straight face these days? Don’t worry, she’ll be right.

On the benefits of natural history knowledge

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I am reminded today about the importance of ecologists knowing a good deal of natural history. Every species is in some sense a unique experiment in evolution, and our job as population and community ecologists is to understand how these species operate in the ecosystems in which they live. But this means we must know the details about how the species operates, what it eats and who eats it, and in some sense how it thinks about its world. I suspect that this is easier to do with higher vertebrates than it is with insects or protozoa but we need to do the same with all forms of life if we are to achieve ecological understanding.

There is in my experience a great lack of this approach in the universities I have seen. We no longer tend to teach about angiosperm systematics, or mammalogy, or ornithology. These are completely old fashioned, the world’s most condemning epithet. So we turn out biology students in British Columbia that cannot identify a Douglas fir tree (perhaps the most important forest tree in the province) and California students who think the eucalyptus trees originated in Berkeley. That would all be well if we perfected bar-coding on our iPhones for species IDs so we could spend more time learning about where and how these species live and die. But too often we seem to think there is a short cut to understanding species roles. It is always worth exploring short cuts to understanding if we can effectively make a simpler way to explain the world. But we try and fail at this enterprise again and again. Hope springs eternal. We need to know now, so let us assume that all algae can be grouped as one ‘superspecies’ in our models, and all ‘rats’ are bad and need to be exterminated, and adding CO2 to the air will make all plants grow faster. We learn by a lot of difficult and extended research that these are oversimplifications. But then the problem becomes communicating this complexity to politicians and the public who desire simplicity rather than complexity.

This whole task is much easier if you talk to a birder who being keen on birds knows that they all differ in many interesting ecological characters, that some individuals of the same species behave in quite different ways, and that the ecosystem continues to operate with this amazing complexity. So I think one solution to ecological oversimplification is to quiz those who start to tell you about harvesting whales, or poisoning rats, or bringing in genetically modified crops to find out how much they know about the natural history of the species they talk so confidently about. A dose of humility would not hurt our discussions of the current controversies of wildlife and fisheries management.

On publishing in SCIENCE and NATURE

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We are having an ongoing discussion at the University of Canberra Institute for Applied Ecology about the need to obtain a measure of our strength in research. We have entered the age of quantification of all things even those that cannot be quantified, and so each of us must get our ranking from our citation rates or h-scores, or journal impact factors. And institutes rise and fall along with our research grants on the basis of these numbers. All of this seems to be necessary but is quite silly for two reasons. First, the importance of any particular paper or idea can only be judged in the long term, so trying to decide if you should have a job because of your citation rate is a cop out. Second, this quantification undermines the importance of judgment of scientists and administrators as adjudicators of the relative merits of specific research and specific scientists. The problem is that as a young scientist in particular you are caught in a web of nonsense and you have to play the game.

The name of the game is to get a paper in SCIENCE or NATURE. To do this you must shorten the presentation so much that it is nearly unintelligible and violates the staid assumption that a scientific paper must have enough detail in it that someone else can repeat the study and test its conclusions. These details are typically left to be put in the supplementary materials that one can download separately from the published paper. So these papers become like headlines in a newspaper, giving a grand conclusion with little of the details of how it was reached. But this publication is the hallmark of success so one must try. The only rule I can suggest is to have a Plan B for publication since about 99% of papers are rejected from SCIENCE AND NATURE.

There is a demography at work here that we must keep in mind. If scientific output is doubling every 7 years approximately, then getting a paper into SCIENCE or NATURE now is twice as hard as it was 7 years ago, on a totally random model of acceptance. So when your supervisor tells you that he or she got a paper in SCIENCE xx years ago, and so should you now, you might point out the demographic momentum of science.

Editors of any journal especially SCIENCE and NATURE are under great pressure, and if anyone thinks that their decisions are completely unbiased, they probably think that the earth is flat. All of us think some parts of our science are more important than others, and editorial decisions are far from perfect. The important message for young scientists is not to get discouraged when rejection slips appear. Any senior scientist could paper the hallways with letters of rejection from various journals. The important thing is to do good research, test hypotheses, make interesting speculations that can be tested, and move on, with or without a paper in SCIENCE or NATURE.

Finally, if someone wants an interesting project, you might trace the history of papers that have appeared in SCIENCE and NATURE over the last 50 years and see how many of them have been significant contributions to the ecological science we recognize now. Perhaps someone has done this already and it has been rejected by SCIENCE and is sitting in a filing cabinet somewhere…….