Category Archives: General Ecology

Why Do Physical Scientists Run Off with the Budget Pie?

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Take any developed country on Earth and analyse their science budget. Break it down into the amounts governments devote to physical science, biological science, and social science to keep the categories simple. You will find that the physical sciences gather the largest fraction of the budget-for-science pie, the biological sciences much less, and the social sciences even less. We can take Canada as an example. From the data released by the research councils, it is difficult to construct an exact comparison but within the Natural Sciences and Engineering Research Council of Canada the average research grant in Chemistry and Physics is 70% larger than the average in Ecology and Evolution, and this does not include supplementary funding for various infrastructure. By contrast the Social Sciences and Humanities Research Council reports research grants that appear to be approximately one-half those of Ecology and Evolution, on average. It seems clear in science in developed countries that the rank order is physical sciences > biological sciences > social sciences.

We might take two messages from this analysis. If you listen to the news or read the newspapers you will note that most of the problems discussed are social problems. Then you might wonder why social science funding is so low on our funding agenda in science. You might also note that environmental problems are growing in importance and yet funding for environmental research is also at the low end of our spending priority.

The second message you may wish to ask is: why should this be? In particular, why do physical scientists run off with the funding pie while ecologists and environmental scientists scratch through the crumbs? I do not know the answer to this question. I do know that it has been this way for at least the last 50 years, so it is not a recent trend. I can suggest several partial answers to this question.

  1. Physical scientists produce along with engineers the materials for war in splendid guns and aircraft and submarines that our governments believe will keep us safe.
  2. Physical scientists produce economic growth by their research so clearly they should be more important.
  3. Physical sciences produce scientific progress on a time scale of months while ecologists and environmental scientists produce research progress on a time scale of years and decades.
  4. Physical scientists do the research that produce good things like iPhones and computers while ecologists and environmental scientists produce mostly bad news about the deterioration in the earth’s ecosystem services.
  5. Physical scientists and engineers run the government and all the major corporations so they propagate the present system.

Clearly there are specific issues that are lost in this general analysis. Medical science produces progress in diagnosis and treatment as a result of the research of biochemists, molecular biologists, and engineers. Pharmaceutical companies produce compounds to control diseases with the help of molecular biologists and physiologists. So research in these specific areas must be supported well because they affect humans directly. Medical sciences are the recipient of much private money in the quest to avoid illness.

Lost in this are a whole other set of lessons. Why were multi-billions of dollars devoted to the Large Hadron Collider Project which had no practical value at all and has only led to the need for a Very Large Hadron Collider in future to waste even more money? The answer seems to lie somewhere in the interface of three points of view – it may be needed for military purposes, it is a technological marvel, and it is part of physics which is the only science that is important. The same kind of thinking seems to apply to space research which is wildly successful burning up large amounts of money while generating more military competition via satellites and in addition providing good movie images for the taxpayers.

While many people now support efforts on the conservation of biodiversity and the need for action on climate change, the funding is not given to achieve these goals either from public or private sources. One explanation is that these are long-term problems and so are difficult to get excited about when the lifespan of the people in power will not extend long enough to face the consequences of current decision making. Finally, many people are convinced that technological fixes will solve all environmental problems so that the problems environmental scientists worry about are trivial (National Research Council 2015, 2015a). Physics will fix climate change by putting chemicals into the stratosphere, endangered species will be resurrected by DNA, and fossil fuels will never run out. And as a bonus Canada and Scandinavia will be warmer and what is wrong with that?

An important adjunct to this discussion is the question of why economics has risen to the top of the heap along with physical sciences. As such the close triumvirate of physical sciences-engineering-economics seems to run the world. We should keep trying to change that if we have concern for the generations that follow.

 

National Research Council. 2015. Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration. The National Academies Press, Washington, DC. 140 pp. ISBN: 978-0-309-36818-6.

National Research Council. 2015a. Climate Intervention: Reflecting Sunlight to Cool Earth. The National Academies Press, Washington, DC. 234 pp. ISBN: 978-0-309-36821-6.

On Broad Issues in Ecology

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Any young ecologist wishing to get a grasp on the most important ecological questions of the century could find no better place to start than the thoughtful compilations of Bill Sutherland and his colleagues in the U.K. (Sutherland et al. 2006; Sutherland et al. 2010; Sutherland et al. 2013). In general none of these questions by itself could be the focus of a thesis which by definition must deal with something concrete in a 2-3 year time frame, but they can serve as an overarching goal for a life in science. In all of these exercises an attempt was made to canvass dozens to hundreds of ecologists mainly from Britain but including many from other parts of the world to suggest and then cull down questions into a feasible framework.

This whole approach is most useful, but the authors recognize there are some limitations on exercises of this type. A particularly crucial limitation is:

“…there was a tendency to pose broad questions rather than the more focussed question we were aiming for. There is a tension between posing broad unanswerable questions and those so narrow that they cease to be perceived as fundamental.” (Sutherland et al. 2013, p 60).

I want to focus here on the problems of decomposing broad unanswerable questions in ecology to guide our ecological research in the future. I will discuss here only two of the population ecology questions.

Begin with question 13 on page 61 of Sutherland et al. (2013):

13. How do species and population traits and landscape configuration interact to determine realized dispersal distances?

To translate this into a project we have first to decide on a species to study and specific populations of that species. This opens Pandora’s Box because there are many thousands of species and we have to pick. We do not pick the species at random, yet we wish to develop a general answer to this question, so right away we are lost in how to translate detailed species and area specific data on movements into a general conclusion. So just for illustration suppose we pick a convenient mammal like the red squirrel of North America. It is territorial and diurnal and can be fitted with GPS collars so that movements can be readily measured, so in a sense it would be considered an ideal species to study to answer question 13, even though it is not a random choice. It ranges from Alaska to Labrador down to Arizona and North Carolina. There are a variety of landscapes throughout this geographic range, some highly altered by humans, some not. I do not know how many intensive studies of red squirrels are being or have been carried out. I would wager that the entire NSF (or NSERC, or ARC) budget could be spent to set up a series of studies of duration 5-20 years to gather these data throughout the range of this species. Clearly this will never be done, and we can only hope that the results of a few specific studies in non-randomly chosen areas over shorter time periods will answer question 13 for this one species.

Landscape configuration alone boggles my mind. It is in many areas an historical artifact of fire or human occupation and land use, and yet we need principles to generalize about it. We can model it and pretend that our models mimic reality without the availability of an experimental test. Is this the ecology of the future?

Another way to answer question 13 is to use tiny organisms like insects that we can replicate readily in small areas at minimal cost. Such studies are useful but again I am not sure they will provide a general answer to question 13. These studies can provide insights about specific insects in specific communities and with a good number of such studies on a variety of systems perhaps we would be in a position to achieve some generality. Otherwise we could be accused of “stamp collecting”.

Question 14 (Sutherland et al. 2013 page 61) has similar problems to question 13 but is more tractable I think.

14 What is the heritability/genetic basis of dispersal and movement behaviour?

This is a simpler question, given modern genetics, and can be answered for a particular species in a particular ecosystem. It is restrictive, if it is a field study, in allowing only those species that do not disperse beyond the detection range of the equipment used, and in requiring long-term genetic paternity data to estimate heritability. The methods are available but have so far been used on few species in very specific areas (e.g. superb fairy wrens in a Botanical Garden, Double et al. 2005). It is an important question to ask and answer but again the generality of the results at the present time have to be assumed rather than measured by replicated studies.

The bottom line is that questions like these two have been with ecologists for some years now and have been answered in some detail only in a few vertebrate species in very specific locations. How we generalize these results is an open question even with modern technology.

Double, M.C., Peakall, R., Beck, N.R., and Cockburn, A. 2005. Dispersal, philopatry, and infidelity: dissecting local genetic structure in superb fairy-wrens (Malurus cyaneus). Evolution 59(3): 625-635.

Sutherland, W.J. et al. 2006. The identification of 100 ecological questions of high policy relevance in the UK. Journal of Applied Ecology 43(4): 617-627. doi:10.1111/j.1365-2664.2006.01188.x.

Sutherland, W.J.et al. 2010. A horizon scan of global conservation issues for 2010. Trends in Ecology & Evolution 25(1): 1-7.

Sutherland, W.J. 2013. Identification of 100 fundamental ecological questions. Journal of Ecology 101(1): 58-67. doi:10.1111/1365-2745.12025.

On Graphics in Ecological Presentations

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In the greater scheme of things, how you plot your data in a paper or in a PowerPoint presentation may not be the most important thing to worry about. But if you believe that small things matter, perhaps you should read on. The standard of presentation of data in graphs in ecological presentations is often less good than is desirable. Many authors have tried to help and for more instructions please read Cleveland (1993, 1994).

Begin with a few elementary rules that I should not have to state but are often ignored:

  1. Label the axes and give the units of measure
  2. Do not use a font size that requires a microscope to read.
  3. Do not present point data without some measure of possible error.

Beyond these general rules there are many that become more specific. I want to call attention here to two rules that are often violated even in our best ecological journals. The first and simplest is never to plot in logs. It is bad enough to plot an axis in log-10 units (most people can work out that 2 in log-10 means 100 in real units), but I have never met anyone who can decipher log-e units (what does 4.38 in log-e units mean in real units?). The solution is simple. Label the scales in real units so that for example the scale may read 1-10-100-1000 with equal spacing so the axis is scaled in logs but the units are given in real measurements. In this way the reader has some idea of the scale of changes shown on the graph.

The second and perhaps more controversial problem I find with ecological graphics is the use of histograms for data that should be illustrated as point estimates (with confidence limits). If we take the advice of Cleveland (1993, page 8) histograms would be rare in scientific publications:

“The histogram is a widely used graphical method that is at least a century old. But maturity and ubiquity do not guarantee the efficacy of a tool……The venerable histogram, an old favourite, but a weak competitor, will not be encountered again [in this book].” (Cleveland 1993, p. 8)

He goes on to evaluate a whole array of graphical methods most of which are rarely seen in ecological papers. The box plot is perhaps the most common example he recommends and is available in many graphing packages. But note that EXCEL is not a very good standard for graphics, and while some if its graphics might be useful, caution is recommended. Many graphics options are available in R (http://www.r-project.org/ ) and some in SIGMAPLOT. Discussions about graphics packages on the web are extensive and everyone has their favourite package along with complaints about other packages. The general point is to think carefully about the graphics you use to convey your message to make it as clear as possible.

What exactly is wrong with histograms? They are misleading if the scale of the axis does not start at zero. The width of the bars is misleading if the scales are categories or precise values. The information in each histogram bar is entirely concentrated in the top of the bar and the included error bars. The amount of replication is difficult to evaluate, and distributions of data that are skewed are not presented. Finally, outliers are not identified. Perhaps the message is that if you have data that you think should be presented as a histogram, check Cleveland (1994) to see if there is not a better way to present it to your audience.

A final observation on graphics. I realize that at the present time in movies and games 3-D images and animations are quite incredible. But remember these are for entertainment not for communication. If you think your PowerPoint requires 3-D graphs with animations, be sure to check whether you are aiming more for entertainment than clear communication.

Cleveland, W.S. 1993. Visualizing Data. Hobart Press, Summit, New Jersey.

Cleveland, W.S. 1994. The Elements of Graphing Data. AT&T Bell Laboratories, Murray Hill, New Jersey.

 

Why We Cannot Forget about Weeds

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Weeds are one of world’s most significant ecological problems. As such it is surprising that the word “weeds” does not appear at all in Sutherland et al. (2013), and only once in Sutherland et al. (2006). (Perhaps there are no weeds in the UK.) Weeds affect plant and animal communities in national parks and nature reserves as well as in agricultural landscapes and cities. We have taken a benign neglect attitude toward weeds, perhaps because they are everywhere, but ecologists may also wish to avoid the word ‘weed’ because it is not a useful aggregate term about which we can draw some ecological generalizations. How should we respond to weeds?

I consider ‘weeds’ as a collective term for what might be the worst global example of serious ecological problems (Strayer 2012). But is this collective term a very useful one? At the first step when we deal only with plants, we get confused with native plants and exotic plants. A utilitarian perspective looks at all plants to see if they are useful or harmful for humans. So some conservation biologists want to get rid of all exotic plants outside of gardens and crops, and others wish to limit all harmful plants, whether native or exotic, and call them ‘weeds’. So the rose in your front yard is indeed an exotic species but a good one. Farmers want to get rid of at least some weeds to maximize production but at the same time to tolerate other exotic species that increase production. Weeds might be thought of as a convenient grouping to simplify ecological generalizations. But alas it has not been so.

The War against Weeds is in general not going well for conservation biologists (Downey et al. 2010). While biological control is very useful for some weeds, it does not at present seem to work for most weeds of national concern. So it does not seem to be a universal solution. Herbicides work for a time and then natural selection intervenes. The problem is that weed problems are very much a local problem in being species-specific and environment-specific, so that there is no overall weed strategy that works everywhere (Vilà et al. 2011). If one is interested in community productivity, weeds may increase plant biomass which might be considered a good result for the ecosystem. Graziers may encourage weeds that plant ecologists would consider destructive to natural communities. Ecosystem ecologists might welcome weeds that increase plant cover if they reduce soil erosion and nutrient leakage into water bodies.

This conflict of interest comes home to us in quarantine restrictions on weeds. In Australia government research scientists work to increase the tolerance of exotic pasture grassess to cold and drought, even though the species in question is a weed of national significance, and improving it genetically will make it more invasive in natural communities (Driscoll et al. 2014). The problem comes back to who wants what kind of an ecological world. Generalist grazing mammals may care little about the exact species composition of the grasslands they inhabit, or alternately they may be poisoned by specific weeds that are toxic to farm animals. The devil rests in the details, so the general message is that we cannot forget species names and attributes in the War on Weeds.

As a minimum, we ought to encourage our governments to place quarantine restrictions on all plant species listed as global weeds of significance. For the present time the best predictor of whether or not an introduced plant will become a destructive weed is: what happened to that plant in other countries to which it was introduced? That you can still buy at your local plant store the seeds of an array of weeds of national significance shouts to ecologists that quarantine systems needs to be strengthened. The War on Weeds is greatly under-financed like many long term problems in ecology, and we should put more effort into developing tactics to deal with destructive weeds rather than ignoring them.

Downey, P.O. et al. 2010. Managing alien plants for biodiversity outcomes—the need for triage. Invasive Plant Science and Management 3(1): 1-11. doi:10.1614/ipsm-09-042.1.

Driscoll, D.A. et al. 2014. New pasture plants intensify invasive species risk. Proceedings of the National Academy of Sciences USA 111(46): 16622-16627. doi:10.1073/pnas.1409347111.

Strayer, D.L. 2012. Eight questions about invasions and ecosystem functioning. Ecology Letters 15(10): 1199-1210. doi:10.1111/j.1461-0248.2012.01817.x.

Sutherland, W.J. et al. 2006. The identification of 100 ecological questions of high policy relevance in the UK. Journal of Applied Ecology 43(4): 617-627. doi:10.1111/j.1365-2664.2006.01188.x.

Sutherland, W.J. et al. 2013. Identification of 100 fundamental ecological questions. Journal of Ecology 101(1): 58-67. doi:10.1111/1365-2745.12025.

Vilà, M., et al. 2011. Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems. Ecology Letters 14(7): 702-708. doi:10.1111/j.1461-0248.2011.01628.x.

Ecosystem Science to the Rescue

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What can ecologists do to become useful in the mess that is currently the 21st Century? In Australia we have a set of guidelines now available as “Foundations for the Future: A Long Term Plan for Australian Ecosystem Science” (http://www.ecosystemscienceplan.org.au ) It is a useful overall plan in many respects and the only question I wish to discuss here is how we ecologists come to such plans and whether or not they are realistic.

We should begin by treating this plan as an excellent example of political ecology – a well presented, glossy brochure, with punch lines carved out and highlighted so that newspaper reporters and sympathetic politicians can present sound bites on air or in Parliament. One example: “Healthy ecosystems are the cornerstone of our social and economic wellbeing”. No arguments there.

Six key directions are indicated:

  1. Delivering maximum impact for Australia: Enhancing relationships between scientists and end-users
  2. Supporting long-term research
  3. Enabling ecosystem surveillance
  4. Making the most of data resources
  5. Inspiring a generation: Empowering the public with knowledge and opportunities
  6. Facilitating coordination, collaboration and leadership

Most ecologists would agree with all 6 key directions, but perhaps only 2 and 3 are scientific goals that are key to research planning. Everyone supports 2, but how do we achieve this without adequate funding? Similarly 3 is an admirable direction but how is it to be accomplished? Could we argue that most ecologists have been trying to achieve these 6 goals for 75 years, and particularly goals 2 and 3 for at least 35 years?

As a snapshot of the importance of ecosystem science, the example of the Great Barrier Reef is presented, and in particular understanding reef condition and its changes over time.

“Australia’s Great Barrier Reef is one of the seven wonders of the natural world, an Australian icon that makes an economic contribution of over $5 billion annually. Ongoing monitoring of the reef and its condition by ecosystem scientists plays a vital role in understanding pressures and informing the development of management strategies. Annual surveys to measure coral cover across the Great Barrier Reef since 1985 have built the world’s most extensive time series data on reef condition across 214 reefs. Researchers have used this long-term data to assess patterns of change and to determine the causes of change.”

The paper they cite (De’ath et al. 2012) shows a coral cover decline on the Great Barrier Reef of 50% over 27 years, with three main causes: cyclones (48% of total), crown-of-thorns starfish (43%) and coral bleaching (10%). From a management perspective, controlling the starfish would help recovery but only on the assumption that the climate is held stable lest cyclones and bleaching increase in future. It is not clear at all to me how ecosystem science can assist reef recovery, and we have in this case another good example of excellent ecological understanding with near-zero ability to rectify the main causes of reef degradation – climate change and water pollution.

The long-term plan presented in this report suggests many useful activities by which ecosystem studies could be more integrated. Exactly which ecosystem studies should be considered high priority are left for future considerations, as is the critical question of who will do these studies. Given that many of the originators of this ecosystem plan are from universities, one worries whether universities have the resources or the time frame or the mandate to accomplish all these goals which are essentially government services. With many governments backing out of serious ecosystem research because of budget cuts, the immediate future does not look good. Nearly 10 years ago Sutherland et al. (2006) gathered together a list of 100 ecological questions of high policy relevance for the United Kingdom. We should now go back to see if these became a blueprint for success or not.

De’ath, G., Fabricius, K.E., Sweatman, H., and Puotinen, M. (2012). The 27–year decline of coral cover on the Great Barrier Reef and its causes. Proceedings of the National Academy of Sciences 109(44): 17995-17999. doi:10.1073/pnas.1208909109.

Sutherland, W.J., et al. (2006). The identification of 100 ecological questions of high policy relevance in the UK. Journal of Applied Ecology 43(4): 617-627. doi: 10.1111/j.1365-2664.2006.01188.x

 

The Naïve Ecologist

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I confess to being a member of the Naïve Ecologist Society. I began research when Zoology and Botany Departments typically consisted of a great mix of scientists working at different levels of biological organization from cells and molecules to ecosystems. As far as I can remember no one thought that it was our job to save the Earth or even a part of it. Our job was to do good science to help understand the processes we see in front of us. Physiologists studied ion transfer in the gills of fish, and muscle energetics, geneticists tried to unravel the genetics of protozoa, and developmental biologists tried to understand the embryology and endocrinology of sex determination. We thought that it was the universities’ job to do excellent teaching and research, and the government’s job to take care of the society and to protect and enhance our natural environment.

Now time warp about 40-50 years later. As far as I can see the molecular and cellular physiologists and geneticists are doing the same thing now as they did then. The tools of course are much improved, their knowledge base has vastly expanded, and modern genetic technology has provided insights into how things work that no one could have imagined long ago. But still (in my experience) if you talk to these sub-organismal biologists in general they will still not tell you they are trying to save the Earth by doing science. They will certainly twist and turn to convince the granting agencies that their work is critical to solving all the problems of humanity, but everyone knows that this is fluff and will be immediately tossed off when the money is delivered. But somehow at the present time it has become the job of the ecologist to save the Earth from human destruction. There is no time left to do pure ecological research to try to find out how ecosystems work and how species interact. We must have answers now to all the pressing questions of conservation biology, and if you wish to get funding for your research you had best try to bend your goals to the solution of climate change, ecosystem services, adaptation, and evolution in the days ahead. There is no time to think and study and observe, we must know now what to do. So we build models of unknown validity and speculate with little data about plans to save the Earth based on untested theory. No other postgraduate student or scientist in a university will operate under this imperative.

This would not be a serious problem if we had a better division between more basic ecologists in universities and more applied ecologists in government labs. Some of this division still exists in some countries, but in many cases governments have cut applied ecology research programs to save money and have turned their applied ecologists into paper pushers assigned to stamp approval on environmental impact statements they have no time or resources to evaluate. So a partial solution to this problem would be to fund more applied ecology positions in government with the resources and regulatory authority to protect as much ecological integrity as possible. State of the Environment glossy brochures are not a substitute for ecological information on environmental impacts, and when you read them carefully you can begin to appreciate how little is truly known about the state of our planet.

I enjoy listening to science programs on the radio as it provides a tiny window into what the radio stations think we need to know about science in action. Science broadcasters usually concentrate on the physical sciences because since they have the big money, they must be very important, then on the space sciences, since no one wants to think about how things are on earth, and finally on behavioural ecology, nice stories that warm our hearts about how bees and birds and orchids make a living. The overall mantra is relatively simple: avoid population ecology lest you have to think about the problems of eternal growth and the human population, and avoid community and ecosystem ecology lest you have to provide more bad news about collapsing coral reefs and the impacts of climate change. Keep the Pablum flowing and hope that the Hadron Collider will save us all.

There is a certain irony is the vast expenditures now being used in medicine to make sure humans live a few more years versus the tiny expenditures being given to environmental science to check on the state of natural world. If the human population collapses in the near future, it will not be because they have not made enough progress in medicine to make us all live to be 95 instead of 85. It will be more likely be due to the inability to appreciate the twin juggernauts of overpopulation and pollution that will render the globe a less nice place for us. By that time the gated communities of Los Angeles will be passé and we will be looking for someone to blame.

Are Birds of Any Consequence?

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We all love birds. They are colourful, interesting creatures and they entice many people to a love of nature and then hopefully the conservation of biodiversity. Thus we do not want to get rid of them. A great deal of effort goes into censusing birds and they are often thought of as indicator species of ecosystem health. No one is in favour of ‘Silent Spring’. But let us do a thought experiment.

The question I wish to ask is somewhat different than the important issue of bird conservation: are birds of any consequence to the operational integrity of communities and ecosystems? In the simplest case what would happen, say, to the eastern deciduous forest or the tall grass prairie or the arctic tundra if all the birds in those ecosystems went extinct? Predators that specialize on birds would clearly disappear but I do not know how many bird specialist predators exist. At the same time the parasites of these birds would be gone. But what about the integrity of existing ecosystems?

Can we dismiss the oceans because birds have a negligible effect on oceanic food webs and energy flow? I do not know the answer to this. In forests birds are often thought to keep insect pests of trees under control, but this seems to be unlikely in many systems in which defoliating insects damage trees of many sorts. Perhaps insect outbreaks would increase in frequency if there were no birds. I come away with the image that birds are for the most part of little consequence for terrestrial ecosystems because they are consumers operating at a very low quantitative level. An exception might be tropical forests in which birds are essential pollinators and seed dispersers, but again I am not sure how often they are necessary pollinators or seed dispersers.

All of this speculation is pretty useless, one might argue, because birds are not going to disappear. They may well be reduced in abundance if habitat is lost and habitat loss seems to be a global problem. But there are two aspects of current ecological research that these idle speculations touch on. First, are birds very good model systems for conservation biology? The answer the ecological world seems to have decided is that they are and very much research must be done on birds for this reason. If research time and money is limited, more research on birds means less on other aspects of community and ecosystem dynamics. Should we be concerned about this? Bird research is convenient and sexy, at least in university settings, but is it more of “Nero fiddling while Rome is burning”? One might in fact argue that many birds are the worst possible model system for understanding conservation problems except for those specific to birds. When I was producing a textbook section on population dynamics I tried to find a good solid example of a supposed decline in bird abundance for any species in which the mechanisms of decline were understood. While there are many data on declines, and much hand wringing, there were virtually no examples with hard data on mechanisms except for the vague idea of habitat loss. Maybe mechanisms are unimportant in conservation biology but it seems unlikely that they are superfluous to understanding the larger issues of population dynamics.

The second general question is the converse one of what kinds of organisms should ecologists be concentrating on if we are to make convincing arguments about biodiversity conservation? If changes in community and ecosystem dynamics are looming, so that the future will not look like the past, where should we put our energies to prevent ecosystem collapse? Are insects and invertebrates in general of greater importance that birds or mammals?

Hurlbert (1971, 1997) raised the question of how to determine the general functional importance of a species to a community, and he concluded that the only measure that has been put forward is ‘the sum over all species, of the changes in productivity which would occur on removal of the particular species from the community’. He pointed out that this definition of importance is clear and specific but could never be measured for even a single species in a community for practical reasons. Hurlbert (1997) also recognized that ‘importance’ had now morphed into ‘keystone’ for much of ecology (e.g. Daily et al. 1993), with all the problems associated with the keystone idea. He suggested, as did Walker (1992) that most species are redundant and of little consequence to ecosystem functioning. Much discussion has occurred since these papers and some has morphed into discussions of ‘functional groups’ instead of species. But plant ecologists have in general not addressed the challenges that Hurlbert (1999) asked, and we are far from being able to answer even the hypothetical question in the title of this blog.

Daily, G.C., Ehrlich, P.R., and Haddad, N.M. 1993. Double keystone bird in a keystone species complex. Proceedings of the National Academy of Sciences USA 90(2): 592-594. doi:10.2307/2361101.

Hurlbert, S.H. 1971. The non-concept of species diversity: a critique and alternative parameters. Ecology 52: 577-586.

Hurlbert, S.H. 1997. Functional importance vs. keystoneness: Reformulating some questions in theoretical biocenology. Australian Journal of Ecology 22(4): 369-382.

Walker, B.H. 1992. Biodiversity and ecological redundancy. Conservation Biology 6: 18-23.

Is Community Ecology Impossible?

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John Lawton writing in 1999 about general laws in ecological studies stated:

“…. ecological patterns and the laws, rules and mechanisms that underpin them are contingent on the organisms involved, and their environment…. The contingency [due to different species’ attributes] becomes overwhelmingly complicated at intermediate scales, characteristic of community ecology, where there are a large number of case histories, and very little other than weak, fuzzy generalizations….. To discover general patterns, laws and rules in nature, ecology may need to pay less attention to the ‘middle ground’ of community ecology, relying less on reductionism and experimental manipulation, but increasing research efforts into macroecology.” (Lawton 1999, page 177)

There are two generalizations here to consider: first that macroecology is the way forward, and second that community ecology is a difficult area that can lead only to fuzzy generalizations. I will leave the macroecology issue to later, and concentrate on the idea that community ecology can never develop general laws.

The last 15 years of ecological research has partly justified Lawton’s skepticism because progress in community ecology has largely rested on local studies and local generalizations. One illustration of the difficulty of devising generalities is the controversy over the intermediate disturbance hypothesis (Schwilk, Keeley & Bond 1997; Wilkinson 1999; Fox 2013a; Fox 2013b; Kershaw & Mallik 2013; Sheil & Burslem 2013). In their recent review Kershaw and Mallik (2013) concluded that confirmation of the intermediate disturbance hypothesis for all studies was around 20%. For terrestrial ecosystems only, support was about 50%. What should we do with hypotheses that fail as often as succeed? That is perhaps a key question in community ecology. Kershaw and Mallik (2013) adopt the approach that states that the intermediate disturbance hypothesis will apply only to grassland communities of moderate productivity. The details here are not important, the strategy of limiting a supposedly general hypothesis to a small set of communities is critical. We are back to the issue of generality. It is certainly progress to set limits on particular hypotheses, but it does leave the land managers hanging. Kershaw and Mallik (2013) state that the rationale for current forest harvesting models in the boreal forest relies on the intermediate disturbance hypothesis being correct for this ecosystem. Does this matter or not? I am not sure.

Prins and Gordon (2014) evaluated a whole series of hypotheses that represented the conventional wisdom in community ecology and concluded that much of what is accepted as well supported community ecological theory has only limited support. If this is accepted (and Simberloff (2014) does not accept it) we are left in an era of chaos in which practical ecosystem management has few clear models for how to proceed unless studies are available at the local level.

Should we conclude that community ecology is impossible? Certainly not, but it may be much more difficult than our simple models suggest, and the results of studies may be more local in application than our current general overarching theories like the intermediate disturbance hypothesis.

The devil is in the details again, and the most successful community ecological studies have essentially been population ecology studies writ large for the major species in the community. Evolution rears its ugly head to confound generalization. There is not, for example, a generalized large mammal predator in every community, and the species of predators that have evolved on different continents do not all follow the same ecological rules. Ecology may be more local than we would like to believe. Perhaps Lawton (1999) was right about community ecology.

Fox, J.W. (2013a) The intermediate disturbance hypothesis is broadly defined, substantive issues are key: a reply to Sheil and Burslem. Trends in Ecology & Evolution, 28, 572-573.

Fox, J.W. (2013b) The intermediate disturbance hypothesis should be abandoned. Trends in Ecology & Evolution, 28, 86-92.

Kershaw, H.M. & Mallik, A.U. (2013) Predicting plant diversity response to disturbance: Applicability of the Intermediate Disturbance Hypothesis and Mass Ratio Hypothesis. Critical Reviews in Plant Sciences, 32, 383-395.

Lawton, J.H. (1999) Are there general laws in ecology? Oikos, 84, 177-192.

Prins, H.H.T. & Gordon, I.J. (eds.) (2014) Invasion Biology and Ecological Theory: Insights from a Continent in Transformation.  Cambridge University Press, Cambridge. 540 pp.

Schwilk, D.W., Keeley, J.E. & Bond, W.J. (1997) The intermediate disturbance hypothesis does not explain fire and diversity pattern in fynbos. Plant Ecology, 132, 77-84.

Sheil, D. & Burslem, D.F.R.P. (2013) Defining and defending Connell’s intermediate disturbance hypothesis: a response to Fox. Trends in Ecology & Evolution, 28, 571-572.

Simberloff, D. (2014) Book Review: Herbert H. T. Prins and Iain J. Gordon (eds.): Invasion biology and ecological theory. Insights from a continent in transformation. Biological Invasions, 16, 2757-2759.

Wilkinson, D.M. (1999) The disturbing history of intermediate disturbance. Oikos, 84, 145-147.

On Repeatability in Ecology

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One of the elementary lessons of statistics is that every measurement must be repeatable so that differences or changes in some ecological variable can be interpreted with respect to some ecological or environmental mechanism. So if we count 40 elephants in one year and count 80 in the following year, we know that population abundance has changed and we do not have to consider the possibility that the repeatability of our counting method is so poor that 40 and 80 could refer to the same population size. Both precision and bias come into the discussion at this point. Much of the elaboration of ecological methods involves the attempt to improve the precision of methods such as those for estimating abundance or species richness. There is less discussion of the problem of bias.

The repeatability that is most crucial in forging a solid science is that associated with experiments. We should not simply do an important experiment in a single place and then assume the results apply world-wide. Of course we do this, but we should always remember that this is a gigantic leap of faith. Ecologists are often not willing to repeat critical experiments, in contrast to scientists in chemistry or molecular biology. Part of this reluctance is understandable because the costs associated with many important field experiments is large and funding committees must then judge whether to repeat the old or fund the new. But if we do not repeat the old, we never can discover the limits to our hypotheses or generalizations. Given a limited amount of money, experimental designs often limit the potential generality of the conclusions. Should you have 2 or 4 or 6 replicates? Should you have more replicates and fewer treatment sites or levels of manipulation? When we can, we try one way and then another to see if we get similar results.

A looming issue now is climate change which means that the ecosystem studied in 1980 is possibly rather different than the one you now study in 2014, or the place someone manipulated in 1970 is not the same community you manipulated this year. The worst case scenario would be to find out that you have to do the same experiment every ten years to check if the whole response system has changed. Impossible with current funding levels. How can we develop a robust set of generalizations or ‘theories’ in ecology if the world is changing so that the food webs we so carefully described have now broken down? I am not sure what the answers are to these difficult questions.

And then you pile evolution into this mix and wonder if organisms can change like Donelson et al.’s (2012) tropical reef fish, so that climate changes might be less significant than we currently think, at least for some species. The frustration that ecologists now face over these issues with respect to ecosystem management boils over in many verbal discussions like those on “novel ecosystems” (Hobbs et al. 2014, Aronson et al. 2014) that can be viewed as critical decisions about how to think about environmental change or a discussion about angels on pinheads.

Underlying all of this is the global issue of repeatability, and whether our current perceptions of how to manage ecosystems is sufficiently reliable to sidestep the adaptive management scenarios that seem so useful in theory (Conroy et al. 2011) but are at present rare in practice (Keith et al. 2011). The need for action in conservation biology seems to trump the need for repeatability to test the generalizations on which we base our management recommendations. This need is apparent in all our sciences that affect humans directly. In agriculture we release new varieties of crops with minimal long term studies of their effects on the ecosystem, or we introduce new methods such as no till agriculture without adequate studies of its impacts on soil structure and pest species. This kind of hubris does guarantee long term employment in mitigating adverse consequences, but is perhaps not an optimal way to proceed in environmental management. We cannot follow the Hippocratic Oath in applied ecology because all our management actions create winners and losers, and ‘harm’ then becomes an opinion about how we designate ‘winners’ and ‘losers’. Using social science is one way out of this dilemma, but history gives sparse support for the idea of ‘expert’ opinion for good environmental action.

Aronson, J., Murcia, C., Kattan, G.H., Moreno-Mateos, D., Dixon, K. & Simberloff, D. (2014) The road to confusion is paved with novel ecosystem labels: a reply to Hobbs et al. Trends in Ecology & Evolution, 29, 646-647.

Conroy, M.J., Runge, M.C., Nichols, J.D., Stodola, K.W. & Cooper, R.J. (2011) Conservation in the face of climate change: The roles of alternative models, monitoring, and adaptation in confronting and reducing uncertainty. Biological Conservation, 144, 1204-1213.

Donelson, J.M., Munday, P.L., McCormick, M.I. & Pitcher, C.R. (2012) Rapid transgenerational acclimation of a tropical reef fish to climate change. Nature Climate Change, 2, 30-32.

Hobbs, R.J., Higgs, E.S. & Harris, J.A. (2014) Novel ecosystems: concept or inconvenient reality? A response to Murcia et al. Trends in Ecology & Evolution, 29, 645-646.

Keith, D.A., Martin, T.G., McDonald-Madden, E. & Walters, C. (2011) Uncertainty and adaptive management for biodiversity conservation. Biological Conservation, 144, 1175-1178.

On Research Questions in Ecology

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I have done considerable research in arctic Canada on questions of population and community ecology, and perhaps because of this I get e mails about new proposals. This one just arrived from a NASA program called ABoVE that is just now starting up.

“Climate change in the Arctic and Boreal region is unfolding faster than anywhere else on Earth, resulting in reduced Arctic sea ice, thawing of permafrost soils, decomposition of long- frozen organic matter, widespread changes to lakes, rivers, coastlines, and alterations of ecosystem structure and function. NASA’s Terrestrial Ecology Program is in the process of planning a major field campaign, the Arctic-Boreal Vulnerability Experiment (ABoVE), which will take place in Alaska and western Canada during the next 5 to 8 years.“

“The focus of this solicitation is the initial research to begin the Arctic-Boreal Vulnerability Experiment (ABoVE) field campaign — a large-scale study of ecosystem responses to environmental change in western North America’s Arctic and boreal region and the implications for social-ecological systems. The Overarching Science Question for ABoVE is: “How vulnerable or resilient are ecosystems and society to environmental change in the Arctic and boreal region of western North America? “

I begin by noting that Peters (1991) wrote very much about the problems with these kinds of ‘how’ questions. First of all note that this is not a scientific question. There is no conceivable way to answer this question. It contains a set of meaningless words to an ecologist who is interested in testing alternative hypotheses.

One might object that this is not a research question but a broad brush agenda for more detailed proposals that will be phrased in such a way to become scientific questions. Yet it boggles the mind to ask how vulnerable ecosystems are to anything unless one is very specific. One has to define an ecosystem, difficult if it is an open system, and then define what vulnerable means operationally, and then define what types of environmental changes should be addressed – temperature, rainfall, pollution, CO2. And all of that over the broad expanse of arctic and boreal western North America, a sampling problem on a gigantic scale. Yet an administrator or politician could reasonably ask at the end of this program, ‘Well, what is the answer to this question?’ That might be ‘quite vulnerable’, and then we could go on endlessly with meaningless questions and answers that might pass for science on Fox News but not I would hope at the ESA. We can in fact measure how primary production changes over time, how much CO2 is sequestered or released from the soils of the arctic and boreal zone, but how do we translate this into resilience, another completely undefined empirical ecological concept?

We could attack the question retrospectively by asking for example: How resilient have arctic ecosystems been to the environmental changes of the past 30 years? We can document that shrubs have increased in abundance and biomass in some areas of the arctic and boreal zone (Myers-Smith et al. 2011), but what does that mean for the ecosystem or society in particular? We could note that there are almost no data on these questions because funding for northern science has been pitiful, and that raises the issue that if these changes we are asking about occur on a time scale of 30 or 50 years, how will we ever keep monitoring them over this time frame when research is doled out in 3 and 5 year blocks?

The problem of tying together ecosystems and society is that they operate on different time scales of change. Ecosystem changes in terrestrial environments of the North are slow, societal changes are fast and driven by far more obvious pressures than ecosystem changes. The interaction of slow and fast variables is hard enough to decipher scientifically without having many external inputs.

So perhaps in the end this Arctic-Boreal Vulnerability Experiment (another misuse of the word ‘experiment’) will just describe a long-term monitoring program and provide the funding for much clever ecological research, asking specific questions about exactly what parts of what ecosystems are changing and what the mechanisms of change involve. Every food web in the North is a complex network of direct and indirect interactions, and I do not know anyone who has a reliable enough understanding to predict how vulnerable any single element of the food web is to climate change. Like medieval scholars we talk much about changes of state or regime shifts, or tipping points with a model of how the world should work, but with little long term data to even begin to answer these kinds of political questions.

My hope is that this and other programs will generate some funding that will allow ecologists to do some good science. We may be fiddling while Rome is burning, but at any rate we could perhaps understand why it is burning. That also raises the issue of whether or not understanding is a stimulus for action on items that humans can control.

Myers-Smith, I.H., et al. (2011) Expansion of canopy-forming willows over the 20th century on Herschel Island, Yukon Territory, Canada. Ambio, 40, 610-623.

Peters, R.H. (1991) A Critique for Ecology. Cambridge University Press, Cambridge, England. 366 pp.