Tag Archives: long-term problems

In Praise of Long Term Studies

I have been fortunate this week to have had a tour of the Konza Prairie Long Term Ecological Research (LTER) site in central Kansas. Kansas State University has run this LTER site for about the last 30 years with support from the National Science Foundation (NSF) of the USA. Whoever set up this program in NSF so many years ago deserves the praise of all ecologists for their foresight, and the staff of KSU who have managed the Konza site should be given our highest congratulations for their research plan and their hard work.

The tall grass prairie used to occupy much of the central part of the temperate zone of North America from Canada to Texas. There is almost none of it left, in Kansas about 1% of the original area with the rest given over to agriculture and grazing. The practical person sees this as progress through the lens of dollar bills, the ecologist sees it as a biodiversity catastrophe. The big questions for the tall-grass prairie are clear and apply to many ecosystems: What keeps this community going? Is it fire or grazing or both in some combination? If fire is too frequent, what are the consequences for the plant community of tall-grass prairie, not to mention the aquatic community of fishes in the streams and rivers? How can shrub and tree encroachment be prevented? All of these questions are under investigation, and the answers are clear in general but uncertain in many details about effects on particular species of birds or forbs.

It strikes me that ecology very much needs more LTER programs. To my knowledge Canada and Australia have nothing like this LTER program that NSF funds. We need to ask why this is, and whether this money could be used much better for other kinds of ecological research. To my mind ecology is unique among the hard sciences in requiring long term studies, and this is because the ecological world is not an equilibrial system in the way we thought 50 years ago. Environments change, species geographical ranges change, climate varies, and all of this on top of the major human impacts on the Earth. So we need to ask questions like why is the tall grass prairie so susceptible to shrub and tree encroachment now when it apparently was not this way 200 years ago? Or why are polar bears now threatened in Hudson’s Bay when they thrived there for the last 1000 or more years? The simple answer is that the ecosystem has changed, but the ecologist wants to know how and why, so that we have some idea if these changes can be managed.

By contrast with ecological systems, physics and chemistry deal with equilibrial systems. So nobody now would investigate whether the laws of gravitation have changed in the last 30 years, and you would be laughed out of the room by physical scientists for even asking such a question and trying to get a research grant to answer this question. Continuous system change is what makes ecology among the most difficult of the hard sciences. Understanding the ecosystem dynamics of the tall-grass prairie might have been simpler 200 years ago, but is now complicated by landscape alteration by agriculture, nitrogen deposition from air pollution, the introduction of weeds from overseas, and the loss of large herbivores like bison.

Long-term studies always lead us back to the question of when we can quit such studies. There are two aspects of this issue. One is scientific, and that question is relatively easy to answer – stop when you find there are no important questions left to pursue. But this means we must have some mental image of what ‘important’ questions are (itself another issue needing continuous discussion). Scientists typically answer this question with their intuition, but not everyone’s intuition is identical. The other aspect leads us into the monitoring question – should we monitor ecosystems? The irony of this question is that we monitor the weather, and we do so because we do not know the future. So the same justification can be made for ecosystem monitoring which should be as much a part of our science as weather monitoring, human health monitoring, or stock market monitoring are to our daily lives. The next level of discussion, once we agree that monitoring is necessary, is how much money should go into ecological monitoring? The current answer in general seems to be only a little, so we stumble on with too few LTER sites and inadequate knowledge of where we are headed, like cars driving at night with weak headlights. We should do better.

A few of the 186 papers listed in the Web of Science since 2010 that include reference to Konza Prairie data:

Raynor, E.J., Joern, A. & Briggs, J.M. (2014) Bison foraging responds to fire frequency in nutritionally heterogeneous grassland. Ecology, 96, 1586-1597. doi: 10.1890/14-2027.1

Sandercock, B.K., Alfaro-Barrios, M., Casey, A.E., Johnson, T.N. & Mong, T.W. (2015) Effects of grazing and prescribed fire on resource selection and nest survival of upland sandpipers in an experimental landscape. Landscape Ecology, 30, 325-337. doi: 10.1007/s10980-014-0133-9

Ungerer, M.C., Weitekamp, C.A., Joern, A., Towne, G. & Briggs, J.M. (2013) Genetic variation and mating success in managed American plains bison. Journal of Heredity, 104, 182-191. doi: 10.1093/jhered/ess095

Veach, A.M., Dodds, W.K. & Skibbe, A. (2014) Fire and grazing influences on rates of riparian woody plant expansion along grassland streams. PLoS ONE, 9, e106922. doi: 10.1371/journal.pone.0106922

Is Conservation Ecology a Science?

Now this is certainly a silly question. To be sure conservation ecologists collect much data, use rigorous statistical models, and do their best to achieve the general goal of protecting the Earth’s biodiversity, so clearly what they do must be the foundations of a science. But a look through some of the recent literature could give you second thoughts.

Consider for example – what are the hallmarks of science? Collecting data is one hallmark of science but is clearly not a distinguishing feature. Collecting data on the prices of breakfast cereals in several supermarkets may be useful for some purposes but it would not be confused with science. The newspapers are full of economic statistics about this and that and again no one would confuse that with science. We commonly remark that ‘this is a good scientific way to go about doing things” without thinking too much about what this means.

Back to basics. Science is a way of knowing, of accumulating knowledge to answer questions or problems in an independently verifiable way. Science deals with questions or problems that require some explanation, and the explanation is a hypothesis that needs to be tested. If the test is retrospective, the explanation may be useful for understanding the past. But science at its best is predictive about what will happen in the future, given a set of assumptions. And science always has alternative explanations or hypotheses in case the first one fails. So much everyone knows.

Conservation ecology is akin to history in having a great deal of information about the past but wishing to use that information to inform the future. In a certain sense it has a lot of the problems of history. History, according to many historians (Spinney 2012) is “just one damn thing after another”, so that there can be no science of history. But Turchin disagrees (2003, 2012) and claims that general laws can be recognized in history and general mathematical models developed. He predicts from these historical models that unrest will break out in the USA around 2020 as cycles of violence have broken out in the past every 30-50 years in this country (Spinney 2012). This is a testable prediction in a reasonable time frame.

If we look at the literature of conservation ecology and conservation genetics, we can find many observations of species declines, of geographical range shifts, and many predictions of general deterioration in the Earth’s biota. Virtually all of these predictions are not testable in any realistic time frame. We can extrapolate linear trends in population size to zero but there are so many assumptions that have to be incorporated to make these predictions, few would put money on them. For the most part the concern is rather to do something now to prevent these losses and that is very useful research. But since the major drivers of potential extinctions are habitat loss and climate change, two forces that conservation biologists have no direct control over, it is not at all clear how optimistic or pessimistic we should be when we see negative trends. Are we becoming biological historians?

There are unfortunately too few general ‘laws’ in conservation ecology to make specific predictions about the protection of biodiversity. Every one of the “ecological theory predicts…” statements I have seen in conservation papers refer to theory with so many exceptions that it ought not to be called theory at all. There are some certain predictions – if we eliminate all the habitat a species occupies, it will certainly go extinct. But exactly how much can we get rid of is an open question that there are no general rules about. “Protect genetic diversity” is another general rule of conservation biology, but the consequences of the loss of genetic diversity cannot be estimated except for controlled laboratory populations that bear little relationship to the real world.

The problems of conservation genetics are even more severe. I am amazed that conservation geneticists think they can decide what species are most ‘important’ for future evolution so that we should protect certain clades (Vane-Wright et al. 1991, Redding et al. 2014 and much additional literature). Again this is largely a guess based on so many assumptions that who knows what we would have chosen if we were in the time of the dinosaurs. The overarching problem of conservation biology is the temptation to play God. We should do this, we should do that. Who will be around to pick up the pieces when the assumptions are all wrong? Who should play God?

Redding, D.W., Mazel, F. & Mooers, A.Ø. (2014) Measuring evolutionary isolation for conservation. PLoS ONE, 9, e113490.

Spinney, L. (2012) History as science. Nature, 488, 24-26.

Turchin, P. (2003) Historical dynamics : why states rise and fall. Princeton University Press, Princeton, New Jersey.

Turchin, P. (2012) Dynamics of political instability in the United States, 1780–2010. Journal of Peace Research, 49, 577-591.

Vane-Wright, R.I., Humphries, C.J. & Williams, P.H. (1991) What to protect?—Systematics and the agony of choice. Biological Conservation, 55, 235-254.

The Anatomy of an Ecological Controversy – Dingos and Conservation in Australia

Conservation is a most contentious discipline, partly because it is ecology plus a moral stance. As such you might compare it to discussions about religious truths in the last several centuries but it is a discussion among scientists who accept the priority of scientific evidence. In Australia for the past few years there has been much discussion of the role of the dingo in protecting biodiversity via mesopredator release of foxes and cats (Allen et al. 2013; Colman et al. 2014; Hayward and Marlow 2014; Letnic et al. 2011, and many more papers). I do not propose here to declare a winner in this controversy but I want to dissect it as an example of an ecological issue with so many dimensions it could continue for a long time.

Dingos in Australia are viewed like wolves in North America – the ultimate enemy that must be reduced or eradicated if possible. When in doubt about what to do, killing dingos or wolves has become the first commandment of wildlife management and conservation. The ecologist would like to know, given this socially determined goal, what are the ecological consequences of reduction or eradication of dingos or wolves. How do we determine that?

The experimentalist suggests doing a removal experiment (or conversely a re-introduction experiment) so we have ecosystems with and without dingos (Newsome et al. 2015). This would have to be carried out on a large scale dependent on the home range size of the dingo and for a number of years so that the benefits or the costs of the removal would be clear. Here is the first hurdle, this kind of experiment cannot be done, and only a quasi-experiment is possible by finding areas that have dingos and others that do not have any (or a reduced population) and comparing ecosystems. This decision immediately introduces 5 problems:

  1. The areas with- and without- the dingo are not comparable in many respects. Areas with dingos for example may be national parks placed in the mountains or in areas that humans cannot use for agriculture, while areas with dingo control are in fertile agricultural landscapes with farming subsidies.
  2. Even given areas with and without dingos there is the problem of validating the usual dingo reduction carried out by poison baits or shooting. This is an important methodological issue.
  3. One has to census the mesopredators, in Australia foxes and cats, with further methodological issues of how to achieve that with accuracy.
  4. In addition one has to census the smaller vertebrates presumed to be possibly affected by the mesopredator offtake.
  5. Finally one has to do this for several years, possibly 5-10 years, particularly in variable environments, and in several pairs of areas chosen to represent the range of ecosystems of interest.

All in all this is a formidable research program, and one that has been carried out in part by the researchers working on dingos. And we owe them our congratulations for their hard work. The major part of the current controversy has been how one measures population abundance of all the species involved. The larger the organism, paradoxically the more difficult and expensive the methods of estimating abundance. Indirect measures, often from predator tracks in sand plots, are forced on researchers because of a lack of funding and the landscape scale of the problem. The essence of the problem is that tracks in sand or mud measure both abundance and activity. If movements increase in the breeding season, tracks may indicate activity more than abundance. If old roads are the main sampling sites, the measurements are not a random sample of the landscape.

This monumental sampling headache can be eliminated by the bold stroke of concluding with Nimmo et al. (2015) and Stephens et al. (2015) that indirect measures of abundance are sufficient for guiding actions in conservation management. They may be, they may not be, and we fall back into the ecological dilemma that different ecosystems may give different answers. And the background question is what level of accuracy do you need in your study? We are all in a hurry now and want action for conservation. If you need to know only whether you have “few” or “many” dingos or tigers in your area, indirect methods may well serve the purpose. We are rushing now into the “Era of the Camera” in wildlife management because the cost is low and the volume of data is large. Camera ecology may be sufficient for occupancy questions, but may not be enough for demographic analysis without detailed studies.

The moral issue that emerges from this particular dingo controversy is similar to the one that bedevils wolf control in North America and Eurasia – should we remove large predators from ecosystems? The ecologist’s job is to determine the biodiversity costs and benefits of such actions. But in the end we are moral beings as well as ecologists, and for the record, not the scientific record but the moral one, I think it is poor policy to remove dingos, wolves, and all large predators from ecosystems. Society however seems to disagree.

 

Allen, B.L., Allen, L.R., Engeman, R.M., and Leung, L.K.P. 2013. Intraguild relationships between sympatric predators exposed to lethal control: predator manipulation experiments. Frontiers in Zoology 10(39): 1-18. doi:10.1186/1742-9994-10-39.

Colman, N.J., Gordon, C.E., Crowther, M.S., and Letnic, M. 2014. Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages. Proceedings of the Royal Society of London, Series B 281(1803): 20133094. doi:DOI: 10.1098/rspb.2013.3094.

Hayward, M.W., and Marlow, N. 2014. Will dingoes really conserve wildlife and can our methods tell? Journal of Applied Ecology 51(4): 835-838. doi:10.1111/1365-2664.12250.

Letnic, M., Greenville, A., Denny, E., Dickman, C.R., Tischler, M., Gordon, C., and Koch, F. 2011. Does a top predator suppress the abundance of an invasive mesopredator at a continental scale? Global Ecology and Biogeography 20(2): 343-353. doi:10.1111/j.1466-8238.2010.00600.x.

Newsome, T.M., et al. (2015) Resolving the value of the dingo in ecological restoration. Restoration Ecology, 23 (in press). doi: 10.1111/rec.12186

Nimmo, D.G., Watson, S.J., Forsyth, D.M., and Bradshaw, C.J.A. 2015. Dingoes can help conserve wildlife and our methods can tell. Journal of Applied Ecology 52. (in press, 27 Jan. 2015). doi:10.1111/1365-2664.12369.

Stephens, P.A., Pettorelli, N., Barlow, J., Whittingham, M.J., and Cadotte, M.W. 2015. Management by proxy? The use of indices in applied ecology. Journal of Applied Ecology 52(1): 1-6. doi:10.1111/1365-2664.12383.

Demography Made Simple

I have grown weary of listening to radio and TV new announcers discuss the human population problem. I think a primer of a few principles of population arithmetic might be useful to remind us where we ecologists sit in these discussions. The problem centres on the issue of eternal growth and then the transition of any population from a growing one to a stable one. I concentrate here on human populations but the results apply to any long-lived species.

I list four empirical principles of demography.

  1. No population can continue growing without limit. This generalization is rock solid, so it would be good to keep mentioning it to sceptics of the following generalizations.
  2. Populations grow when births and immigration exceed deaths and emigration. If we consider the entire global human population, emigration and immigration disappear since we have not yet colonized space. Populations stabilize when births equal deaths.
  3. A population that moves from a growth phase to a stable phase must change in age structure. Every stable population must contain fewer young persons and more older persons.
  4. These changes in age structure have enormous implications for our requirements for hospitals, doctors, schools, teachers, and social support agencies. These changes are almost completely predicable for humans and should not come as a surprise to politicians.
  5. Pushing the panic button because a particular population like that of Japan is stabilizing and could even decline slightly may be useful for economists wishing for infinite growth but should be recognized as an expected event for every country in the future.

The bottom line is that we have the knowledge and the ability to plan for the cessation of human population growth. Many good books have been written to make these points and we need to keep repeating them. That many people do not understand the simple arithmetic of population change is a worry, and we should all try to communicate these 5 simple principles to all who will listen.

Cafaro, P., and Crist, E. 2012. Life on the Brink: Environmentalists Confront Overpopulation. University of Georgia Press, Athens, Georgia. 342 pp. ISBN: 978-0-8203-4385-3

Daly, H.E., and Farley, J. 2011. Ecological Economics: Principles and Applications. 2nd ed. Island Press, Washington, D.C. 509 pp. ISBN: 978-1-5972-6681-9

Washington, H. 2015. Demystifying Sustainability: Towards Real Solutions. Routledge, New York. 222 pp. ISBN: 978-1138812697

Why Do Physical Scientists Run Off with the Budget Pie?

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

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.

Why We Cannot Forget about Weeds

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.

On Repeatability in Ecology

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

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.

Large Mammal Conservation

The conservation problem is largely focused on large things, birds and mammals, with a few pretty things like butterflies thrown in. What concerns me is the current distortion in the conservation knowledge base available for large animal conservation. I will talk largely about mammals but large birds are equally a problem.

The difficulty is this. It is nearly impossible to study large mammals because they are scarce on the ground, so census methods must be spatially extensive and thus very expensive. One needs a big budget to do this properly, and this effectively rules out university scientists unless they can collaborate with government biologists who have large budgets or private consortia who need the large mammals so they can shoot them. But even with a large budget, a large mammal ecologist cannot be very productive as measured in papers per year of research effort. So the universities in general have shied away from hiring young scientists who might be described as large mammal ecologists. This produces positive feedback in the job market so that few young scientists see this as a viable career.

All of this would be changed if governments were hiring large mammal ecologists. But they are not, with few exceptions. Governments at least in Canada and Australia have been shedding ecologists of all varieties while all the time professing how much they are doing for conservation of threatened species. The advantage of this approach for governments is that they shed high cost biologists, and cover their tracks with some hiring of public relations personnel who have no field costs and perhaps a few biologists who concentrate on small creatures and local problems. So we reach a stalemate when it comes to large mammal conservation. Why do we need polar bear scientists when all they do is make trouble? We can escape such trouble easily. Count the polar bears or the caribou every 5 years or so, so there is consequently much less information that scientists can put their fingers on. (Imagine if we counted the stock market once every 5 years.) The consequence is that in many areas we have large scale, long-term problems with few scientists and only small scale funding to find out what is happening in the field. For polar bears this seems to be partly alleviated by private funding from people who care, while the government shirks its duties for future generations.

For caribou in Canada the situation is worse because the problem is spread over more than half of Canada so the funding and person-power needed for conservation is much larger, and this is further compounded by the immediate conflict of caribou with industrial developments in oil, gas, and forestry. When dollars conflict with conservation needs, it is best not to bet on conservation winning. What good has a polar bear or a caribou done for you?

The potential consequence of all this is that we slowly lose populations of these large iconic species. If this loss is slow enough, no one seems to notice save a few concerned conservation biologists who do not own the newspapers and TV stations. And conservation ecologists grow pessimistic that we can save these large species that require much habitat and freedom from disturbance. The solutions seem to be two. First, build a big fence and keep them in a very large zoo (Packer et al. 2013). This will work for some species like caribou, as Kruger Park in South Africa illustrates so well with African large mammals (but some disagree, Creel et al. 2013). But the fence-solution will not work for polar bears, and our best response for their conservation may be to cross our fingers and hope, all the while trying to slow down the losses in the best way we can. A second solution is to decide that these large mammal conservation situations are not scientific but sociological, and progress can best be made by doing good sociological research to change the attitudes of humans about the value of biodiversity. If this is the solution, we do not need to worry that there are no biologists available to investigate the conservation issues of large mammals.

I think perhaps the bottom line is that it takes a spirited soul to aim for a career in large mammal conservation research and we hope that this happens and the conservation future for large mammals in Canada grows brighter.

Creel, S., 2013. Conserving large populations of lions – the argument for fences has holes. Ecology Letters 16 (5): 635-641. doi: 10.1111/ele.12145.

Packer, C., et al. 2013. Conserving large carnivores: dollars and fence. Ecology Letters. 16: 1413-e3. doi: 10.1111/ele.12091.

Pauly, D. 1995. Anecdotes and the shifting baseline syndrome of fisheries. Trends in Ecology and Evolution 10: 430.