Category Archives: Charley Krebs’ blogs

On Logging Old Growth Forests

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Old growth forests in western Canada and many parts of the Earth are composed of very large trees whose diameters are measured in meters and whose heights are measured in football field lengths. The trees in these forests are economically valuable for their wood, and this has produced a conflict that almost all governments wish to dodge. I do not want to speak here as a terrestrial ecologist but as a human being to discuss the consequences of logging these old growth forests.

As I write this there are a mob of young people blockading the roads into old-growth forest stands in southwestern British Columbia to prevent the logging of some of the largest trees remaining in coastal western Canada. Their actions are all illegal of course because the government has given permission to companies to log these large trees, the classic case of ‘we need jobs’. We certainly need jobs, and we need wood, but if you ask the citizens of British Columbia if these very large trees should be logged you get a resounding majority of NO votes. The government is adept at ignoring the majority will here, it is called democracy.

My simple thought is this. These trees are 500 to 1000 years old. Cut them all down and your children will never see a big tree, or their children or perhaps 25 generations of children, since the foresters say that this is sustainable logging because, if left alone, the forest will regenerate into large old growth trees again by the year 2900. A splendid program for all except for our children for the nest 800 years.

The other ecological issue of course is that these forests form an ecosystem, so it is not just the loss of large old trees but all the other plants and animals in this ecosystem that will be lost. To be sure you can argue that all this forest management is completely sustainable, and you will be able to see this clearly if you are still alive in 2900. Sustainability has unfortunately become a meaningless term in much of our forest land management. Forest management could become sustainable, as many ecologists have been saying for the last 50 years, but as with agriculture the devil is in the details of what this actually means. And if the forest management plan to retain old growth is to keep 6 very large trees somewhere in coastal British Columbia, each one surrounded by a fence and a ring of high-rise hotels for tourists of the future to see “old growth”, then we are well on our way there.

Guz, J. and Kulakowski, D. (2020). Forests in the Anthropocene. Annals of the American Association of Geographers 110, 1-11. doi: 10.1080/24694452.2020.1813013.

Lindenmayer, D.B., et al. (2020). Recent Australian wildfires made worse by logging and associated forest management. Nature Ecology & Evolution 4, 898-900. doi: 10.1038/s41559-020-1195-5.

Thorn, S., et al. (2020). The living dead: acknowledging life after tree death to stop forest degradation. Frontiers in Ecology and the Environment 18, 505-512. doi: 10.1002/fee.2252.

Watson, J.E.M., et al. (2018). The exceptional value of intact forest ecosystems. Nature Ecology & Evolution 2, 599-610. doi: 10.1038/s41559-018-0490-x.

How Much Evidence is Enough?

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The scientific community in general considers a conclusion about a problem resolved if there is enough evidence. There are many excellent books and papers that discuss what “enough evidence” means in terms of sampling design, experimental design, and statistical methods (Platt 1964, Shadish et al. 2002, Johnson 2002, and many others) so I will skip over these technical issues and discuss the nature of evidence we typically see in ecology and management.

An overall judgement one can make is that there is a great diversity among the different sciences about how much evidence is enough. If replication is expensive, typically fewer experiments are deemed sufficient. If human health is involved, as we see with Covid-19, many controlled experiments with massive replication is usually required. For fisheries and wildlife management much less evidence is typically quoted as sufficient. For much of conservation biology the problem arises that no experimental design can be considered if the species or taxa are threatened or endangered. In these cases we have to rely on a general background of accepted principles to guide our management actions. It is these cases that I want to focus on here.

Two guiding lights in the absence of convincing experiments are the Precautionary Principle and the Hippocratic Oath. The simple prescription of the Hippocratic Oath for medical doctors has always been “Do no harm”. The Precautionary Principle has been spread more widely and has various interpretations, most simply “Look before you leap” (Akins et al. 2019). But if applied too strictly some would argue, this principle might stop “green” projects that are in themselves directed toward sustainability. Wind turbine tower effects on birds are one example (Coppes et al. 2020). The conservation of wild bees may impact current agricultural production positively (Drossart and Gerard 2020) or negatively depending on the details of the conservation practices. Trade offs are a killer for many conservation solutions, jobs vs. the environment.

Many decisions about conservation action and wildlife management rest on less than solid empirical evidence. This observation could be tested in any graduate seminar by dissecting a series of papers on explicit conservation problems. Typically, those cases involving declining large bodied species like caribou or northern spotted owls or tigers are affected by a host of interconnected problems involving human usurpation of habitats for forestry, agriculture, or cities, backed up by poaching or direct climate change due to air pollution, or diseases introduced by domestic animals or introduced species. In some fraction of cases the primary cause of decline is well documented but cannot be changed by conservation biologists (e.g. CO2 and coral bleaching). 

Nichols et al. (2019) recommend a model-based approach to answering conservation and management questions as a way to increase the rate of learning about which set of hypotheses best predict ecological changes. The only problem with their approach is the time scale of learning, which for immediate conservation issues may be limiting. But for problems that have a longer time scale for hypothesis testing and decision making they have laid out an important pathway to problem solutions.

In many ecological and conservation publications we are allowed to suggest weak hypotheses for the explanation of pest outbreaks or population declines, and in the worst cases rely on “correlation = causation” arguments. This will not be a problem if we explicitly recognize weak hypotheses and specify a clear path to more rigorous hypotheses and experimental tests. Climate change is the current panchrestron or universal explanation because it shows weak associations with many ecological changes. There is no problem with invoking climate change as an explanatory variable if there are clear biological mechanisms linking this cause to population or community changes.

All of this has been said many times in the conservation and wildlife management literature, but I think needs continual reinforcement. Ask yourself: Is this evidence strong enough to support this conclusion? Weak conclusions are perhaps useful at the start of an investigation but are not a good basis for conservation or wildlife management decision making. Ensuring that our scientific conclusions “Do no harm” is a good principle for ecology as well as medicine.

Akins, A., et al. (2019). The Precautionary Principle in the international arena. Sustainability 11 (8), 2357. doi: 10.3390/su11082357.

Coppes, J., et al. (2020). The impact of wind energy facilities on grouse: a systematic review. Journal of Ornithology 161, 1-15. doi: 10.1007/s10336-019-01696-1.

Drossart, M. and Gerard, M. (2020). Beyond the decline of wild bees: Optimizing conservation measures and bringing together the actors. Insects (Basel, Switzerland) 11, 649. doi: 10.3390/insects11090649.

Johnson, D.H. (2002). The importance of replication in wildlife research. Journal of Wildlife Management 66, 919-932.

Nichols, J.D., Kendall, W.L., and Boomer, G.S. (2019). Accumulating evidence in ecology: Once is not enough. Ecology and Evolution 9, 13991-14004. doi: 10.1002/ece3.5836.

Platt, J. R. (1964). Strong inference. Science 146, 347-353. doi: 10.1126/science.146.3642.347.

Shadish, W.R, Cook, T.D., and Campbell, D.T. (2002) ‘Experimental and Quasi-Experimental Designs for Generalized Causal Inference.‘ (Houghton Mifflin Company: New York.)

But It is Complicated in Ecology

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Consider two young ecologists both applying for the same position in a university or an NGO. To avoid a legal challenge, I will call one Ecologist C (as short for “conservative”), and the second candidate Ecologist L (as short for “liberal”). Both have just published reviews of conservation ecology. Person L has stated very clearly that the biological world is in rapid, catastrophic collapse with much unrecoverable extinction on the immediate calendar, and that this calls for emergency large-scale funding and action. Person C has reviewed similar parts of the biological world and concluded that some groups of animals and plants are of great concern, but that many other groups show no strong signals of collapse or that the existing data are inadequate to decide if populations are declining or not. Which person will get the job and why?

There is no answer to this hypothetical question, but it is worth pondering the potential reasons for these rather different perceptions of the conservation biology world. First, it is clear that candidate L’s catastrophic statements will be on the front page of the New York Times tomorrow, while much less publicity will accrue to candidate C’s statements. This is a natural response to the ‘This Is It!” approach so much admired by thrill seekers in contrast to the “Maybe Yes, Maybe No”, and “It Is Complicated” approach. But rather than get into a discussion of personality types, it may be useful to dig a bit deeper into what this question reveals about contemporary conservation ecology.

Good scientists attempting to answer this dichotomy of opinion in conservation ecology would seek data on several questions.
(1) Are there sufficient data available to reach a conclusion on this important topic?
(2) If there are not sufficient data, should we err on the side of being careful about our conclusion and risk “crying wolf”?
(3) Can we agree on what types of data are needed and admissible in this discussion?

On all these simple questions ecologists will argue very strongly. For question (1) we might assume that a 20-year study of a dominant species might be sufficient to determine trend (e.g. Plaza and Lambertucci 2020). Others will be happy with 5 years of data on several species. Can we substitute space for time? Can we simply use genetic data to answer all conservation questions (Hoffmann et al. 2017)? If the habitat we are studying contains 75 species of plants or invertebrates, on how many species must we have accurate data to support Ecologist L? Or do we need any data at all if we are convinced about climate change? Alfonzetti et al, (2020) and Wang et al. (2020) give two good examples of data problems with plants and butterflies with respect to conservation status. 

For question (2) there will be much more disagreement because this is not about the science involved but is a personal judgement about the future consequences of projected trends in species numbers. These judgements are typically based loosely on past observations of similar ecological populations or communities, some of which have declined in abundance and disappeared (the Passenger Pigeon Paradigm) or conversely those species that have recovered from minimal abundance to become common again (the Kirtland’s Warbler Paradigm). The problem revolves back to the question of what are ‘sufficient data’ to decide conservation policies.

Fortunately, most policy-oriented NGO conservation groups concentrate on the larger conservation issues of finding and protecting large areas of habitat from development and pushing strongly for policies that rein in climate change and reduce pollution produced by poor business and government practices.

In the current political and social climate, I suspect Ecologist L would get the job rather than Ecologist C. I can think of only one university hiring in my career that was sealed by a very assured candidate like person L who said to the departmental head and the search committee “Hire me and I will put this university on the MAP!”. We decided in this case we did not want to be on that particular MAP.

At present you can see all these questions are common in any science dealing with an urgent problem, as illustrated by the Covid-19 pandemic discussions, although much more money is being thrown at that disease issue than we ever expect to see for conservation or ecological science in general. It really is complicated in all science that is important to us.

Alfonzetti, M., et al. (2020). Shortfalls in extinction risk assessments for plants. Australian Journal of Botany 68, 466-471. doi: 10.1071/BT20106.

Hoffmann, A.A., Sgro, C.M., and Kristensen, T.N. (2017). Revisiting adaptive potential, population size, and conservation. Trends in Ecology & Evolution 32, 506-517. doi: 10.1016/j.tree.2017.03.012.

Plaza, P.I. and Lambertucci, S.A. (2020). Ecology and conservation of a rare species: What do we know and what may we do to preserve Andean condors? Biological Conservation 251, 108782. doi: 10.1016/j.biocon.2020.108782.

Wang, W.-L., Suman, D.O., Zhang, H.-H., Xu, Z.-B., Ma, F.-Z., and Hu, S.-J. (2020). Butterfly conservation in China: From science to action. Insects (Basel, Switzerland) 11, 661. doi: 10.3390/insects11100661.

On Citations and Scientific Research in Ecology

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Begin with a few common assumptions in science.
(1) Higher citation rates define more valuable science
(2) Recent references are more valuable than older references
(3) Retracted scientific research is rapidly recognized and dropped from discussion
(4) The vast majority of scientific research reported in papers is read by other scientists.
(5) Results cited in scientific papers are cited correctly in subsequent references.

The number of publications in ecological science is growing rapidly world-wide, and a corollary of this must be that the total number of citations is growing even more rapidly (e.g. Westgate et al. 2020). It is well recognized that citations are unevenly spread among published papers, and reports that nearly 50% of published papers never receive any citations at all are commonly cited. I have not been able to validate this for papers in the ecological sciences. The more important question is whether the most highly cited papers are the most significant for progress in ecological understanding. If this is the case, you can simply ignore the vast majority of the published literature and save reading time. But this seems unlikely to be correct for ecological science.

The issue of scientific importance is a time bomb partly because ‘importance’ may be redefined over time as sciences mature, and this redefinition may occur in years or tens of years. A classic example is the citation history of Charles Elton’s (1958) book on invasions (Richardson and Pyšek 2008). Published in 1958, this book had almost no citations until the 1990s. Citations have become more and more important in the ranking of individual scholars as well as university departments during the last 20 years (Keville et al. 2017). This has occurred despite continuous warnings that citations are not valid for comparing individuals of different age or departments in different academic fields (Patience et al. 2017). If you publish in Covid-19 research this year, you are likely to get more citations than the person working in earthworm taxonomy.

Most published papers confirm the general belief that citing the most recent papers is more successful than citing older papers. If this belief could be tested, it would simplify education of graduate students and facilitate teaching. But the simple fact is that in ecology often (but not always) older papers have better perspectives than more recent papers or indicate paths of research that have failed to lead to ecological wisdom. 

Newspapers revel in stories of retracted research, if only to show that scientists are human. Of some interest are studies that show that research which is retracted continues to be cited. Hagberg (2020) cites a case in which a paper was retracted but continued to be cited as much after retraction as before. Fortunately, retracted research is rare in the ecological sciences but not absent, but the various conflicting ways in which scientific journals deal with papers with fraudulent results discovered after they are published leave much to be desired. 

A final comment on references is a warning to anyone reading the discussion or conclusions of a paper. Smith and Cumberledge (2020) have reported a random sample of references in a variety of scientific papers indicated a 25% error rate in ‘quotation’ errors. Quotation errors are distinct from ‘citation errors’ which are minor mistakes in the year of publication, page numbers or names in citations given in papers. Quotation errors are examples of “original paper authors say XX, citing paper says YY, a contradiction to what was originally reported. They used 250 citations from the 5 most highly cited scientific publications of today to determine how many papers contained ‘quotation errors’ and found a 25% error rate. About 33% of these errors could be called ‘Unsubstantiated’ and about 50% of the remaining quotation errors were ‘Impossible to substantiate” category. Their study reinforced early work by Todd et al. (2007) and pointed out to readers a weakness in the current use of references in scientific writing that is often missed by reviewers.

On a more positive note, on how to increase your citation rate, Murphy et al. (2019) surveyed the titles of 3562 papers and their subsequent citation rate from four ecology and entomology journals. They found that papers that did not include the Latin name of species in the title of the paper were cited 47% more often than papers with Latin names in the title. The number of words in the title of the paper had almost no effect on citation rates. They were unable to determine whether the injection of humor in the title of the paper had any effect on citation rates because too few papers attempted humor in the title.   

Elton, C.S. (1958) ‘The Ecology of Invasions by Animals and Plants.’ (Methuen: London.) ISBN: 978-3-030-34721-5

Hagberg, J.M. (2020). The unfortunately long life of some retracted biomedical research publications. Journal of Applied Physiology 128, 1381-1391. doi: 10.1152/japplphysiol.00003.2020.

Keville, M.P., Nelson, C.R., and Hauer, F.R. (2017). Academic productivity in the field of ecology. Ecosphere 8, e01620. doi: 10.1002/ecs2.1620.

Murphy, S.M., Vidal, M.C., Hallagan, C.J., Broder, E.D., and Barnes, E.E. (2019). Does this title bug (Hemiptera) you? How to write a title that increases your citations. Ecological Entomology 44, 593-600. doi: 10.1111/een.12740.

Patience, G.S., Patience, C.A., Blais, B., and Bertrand, F. (2017). Citation analysis of scientific categories. Heliyon 3, e00300. doi: https://doi.org/10.1016/j.heliyon.2017.e00300.

Richardson, D.M. and Pyšek, P. (2008). Fifty years of invasion ecology – the legacy of Charles Elton. Diversity and Distributions 14, 161-168. doi: 10.1111/j.1472-4642.2007.00464.x.

Smith, N. and Cumberledge, A. (2020). Quotation errors in general science journals. Proceedings of the Royal Society. A, 476, 20200538. doi: 10.1098/rspa.2020.0538.

Todd, P.A., Yeo, D.C.J., Li, D., and Ladle, R.J. (2007). Citing practices in ecology: can we believe our own words? Oikos 116, 1599-1601. doi: 10.1111/j.2007.0030-1299.15992.x

Westgate, M.J., Barton, P.S., Lindenmayer, D.B., and Andrew., N.R. (2020). Quantifying shifts in topic popularity over 44 years of Austral Ecology. Austral Ecology 45, 663-671. doi: 10.1111/aec.12938.

On Writing an Abstract for an Ecological Presentation

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There is abundant good general advice for writing an abstract for your thesis, research talk or published paper from the web but it is perhaps useful to add a few points specific to ecological studies. I suggest five points for a good abstract as a condensed version of the traditional writing advice: Who, What, When, Where, How and Why.  

  1. What is the problem, question, or controversy? You must grab the reader in the first sentence or two.
  2. What is your contribution to answering, testing, or changing the question? In a few sentences you should explain what you did, where and when you did it if a field study. If you are testing a hypothesis, you should state the alternative hypotheses as well.
  3. How did you reach your conclusions, what methods did you use? The design of your study should include what species or group of species you included, some general points about sample sizes.
  4. Rotate back to match your conclusions to your prior hypotheses, or the new hypothesis you present.
  5. Finally, state what needs to be done next to further these ecological issues.

The trick is to do all of this in concise sentences, to state clearly your advances in understanding, and equally to state clearly what failed to work the way you had originally postulated.

So, if you can do all of this in 200-300 words, you win the prize. A good abstract is like gold and worth the work.

There is much literature on writing well. Sayer (2019) gives a concise statement of writing for ecological journals. Pollock (2020) emphasizes the responsibility scientists bear for their writing, and Mammola (2020) makes a plea for reducing superlatives in over-selling our conclusions,

If you would like an exercise in a seminar or lab meeting, go through your favourite journal and rank the abstracts in an issue on a scale of 1-10 for both clarity and for enticing you the reader to read the complete details of the rest of the paper.

And go through this same writing routine if you are giving a seminar or lecture and must present a short abstract. We may all be attracted to hear an address on whatever from the Prime Minister or the President, but alas that is not always the case for we mere mortals who must attract an audience to our talks on the basis of our abstract. 

Mammola, S. (2020). On deepest caves, extreme habitats, and ecological superlatives. Trends in Ecology & Evolution 35, 469-472. doi: 10.1016/j.tree.2020.02.011.

Pollock, N.W. (2020). The responsibility of scientific writing. Wilderness & Environmental Medicine 31, 129-130. doi: 10.1016/j.wem.2020.04.005.

Sayer, E.J. (2019). The essentials of effective scientific writing – A revised alternative guide for authors. Functional Ecology 33, 1576-1579. doi: 10.1111/1365-2435.13391.

On a Department of Monitoring Biology

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Begin with the current university structure in North America. Long ago it was simple: a Department of Biology, a Department of Microbiology, a Department of Forestry, and possibly a Department of Fisheries and Wildlife Management. We could always justify a Department of Microbiology because people get sick, a Department of Forestry because people buy wood to build houses, and a Department of Fisheries and Wildlife Management because people fish and hunt. But what are we going to do with a Department of Biology? It rarely deals with anything that will make money, so we divide it into interest groups, a Department of Botany, and a Department of Zoology. All is well. But now a new kid appears on the block, Molecular Biology, and it claims to be able to solve all the issues that were formerly considered the focus of Botany and Zoology and probably several other departments. Give us all the money, the molecular world shouted, and we will solve all your problems and do it quickly. So now we get a complete hassle for money, buildings and prestige, and the world turns on which of the bevy of bureaucrats races to the top to make all the major decisions. If you wish to have proof of concept, ask anyone you can find who teaches at a university if he or she was ever consulted about what direction the university should take.

At this point we begin to proceed based on ‘follow the money’. So, for example if the Department of Forestry gets the most money from whomever, it must get the biggest buildings, the largest salaries, and the newest appointments. So soon you have a system of intrigue that would rival the Vatican. The winners of late are those departments that have most to do with people, health, and profit. So Medical Schools march on, practical matters like economics and engineering do well, and molecular biology rises rapidly.

What has happened to the old Departments of Botany and Zoology? They make no profit; their only goal is to enrich our lives and our understanding of the world around us. How can we make them profitable? A new program races to the rescue, a Department of Biodiversity, which will include everyone in plant, animal and microbe science who cannot get into one of the more practical, rich, existing departments. The program now is to convince the public and the governments that biodiversity is important and must be funded more. David Attenborough to the fore, and we are all abandoning the old botany and zoology and moving to biodiversity.

Now the problem arises for ecologists. Biodiversity includes everything, so where do we start? If we have so far described and named only about 15% of the life on Earth, should we put all our money into descriptive taxonomy? Should we do more biogeography, more ecology, more modelling, or more taxonomy, or a bit of all? So, the final question of our quest arrives: what should we be doing in a Department of Biodiversity if indeed we get one?

If you have ever been involved in herding cats, or even sheep without a dog you can imagine what happens if you attempt to set a priority in any scientific discipline. The less developed the science, the more the arguments about where to put our money and people. Ecology is a good example because it has factions with no agreement at all about what should be done to hasten progress. The result is that we fall back on the Pied Pipers of the day, form bandwagons, and move either forward, sideways, or backwards depending on who is in charge.

So, let us step back and think amid all this fighting for science funding. The two major crises of our time are human population growth and the climate change emergency. In fact, there is only one major crisis, climate change, because as it apparently progresses, everything will be overwhelmed in a way only few can try to guess (Wallace-Wells 2019, Lynas 2020). After some discussion you might suggest that we do two things in biology: first, get a good grip on what we have now on Earth, and second, keep monitoring life on Earth as the climate emergency unravels so that we can respond with mitigation as required. This is not to say we should stop doing other things. We should be more than unifactorial scientists, and it may be a small recommendation to the world of thinkers that we consider endowing at least some universities with a Department of Monitoring Biology and endow it with enough funding to do the job well. (Lindenmayer 2018; Lindenmayer et al. 2018; Nichols et al. 2019). It might be our best investment in the future of biology.

Lindenmayer, D. (2018). Why is long-term ecological research and monitoring so hard to do? (And what can be done about it). Australian Zoologist 39: 576-580. doi: 10.7882/az.2017.018.

Lindenmayer, D.B., Likens, G.E., and Franklin, J.F. (2018). Earth Observation Networks (EONs): Finding the Right Balance. Trends in Ecology & Evolution 33, 1-3. doi: 10.1016/j.tree.2017.10.008.

Lynas, Mark (2020) ‘Our Final Warning: Six Degrees of Climate Emergency’. 4th Estate, Harper Collins, London. E book ISBN: 978-0008308582

Nichols, J.D., Kendall, W.L., and Boomer, G.S. (2019). Accumulating evidence in ecology: Once is not enough. Ecology and Evolution 9, 13991-14004. doi: 10.1002/ece3.5836.

Wallace-Wells, David (2019) ‘The Uninhabitable Earth: Life After Warming ‘ Tim Duggan Books: New York. 304 pp. ISBN: 978-0-525-57670-9.  

How should biodiversity research be directed?

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There are many scientific papers and news reports currently that state that biodiversity is in rapid decline on Earth. No evidence is usually cited for this statement – it is considered to be self evident. What follows from that is typically a panic request for more work on declining populations, more money for conservation NGOs and national parks. Political ecology statements that request more money for ecological research are certainly on the right track if we are to understand how to achieve conservation of our biota. But the question I want to raise here is how to proceed on this broad issue in a logical manner. To do this I will not discuss political ecology or how to gain more donors for conservation agencies, valuable services to be sure. But behind all this advertising is a scientific agenda which needs careful consideration.    

Problem #1 is to determine if there is a problem. In some areas of conservation ecology there is much agreement on principles – we all agree that we are losing natural areas for urban and agricultural development, that we need more protected areas, that most protected areas are not large enough, that there are serious problems with poaching of wildlife and lumber in some protected areas, and that global pollution is affecting much of our biodiversity. In other areas of conservation ecology there is much controversy about details. Is global biodiversity in rapid decline (Vellend et al. 2017, Cardinale et al. 2018)? How can we best identify species at risk, and once we identify them, what can we do to prevent population collapse?

The answer to Problem #1 is that there are problems in some areas but not in others, in some taxonomic groups, but not in others, but overall the data are completely inadequate for a clear statement that overall biodiversity is in global decline (Dornelas et al. 2019). The problems of biodiversity conservation are local and group specific, which leads us to Problem #2.

Problem # 2 is to go back to the ecological details, concentrating on local and specific problems, exactly what should we do, and what can we do? The problems here relate almost entirely to ecological methods – how do we estimate species abundances particularly for rare species? How do we deal with year to year changes in communities? How long should a monitoring program continue until it has reliable conclusions about biodiversity change? None of these questions are simple to answer and require much discussion which is currently under way. How long is a long-term study? It might be something like 30 generations for vertebrate species or even longer, but what is it for earthworms or bark beetles? How can we best sample the variety of insects in an ecosystem in which they might be in decline (Habel et al. 2019)?

We need to scale our conservation studies for particular species, and this has led us into the Species-At-Risk dilemma. We can gather data for a specific geographical area like Canada on the species that we deem at risk. Typically, these are vertebrates, and we ignore the insects, microbes, and the rest of the community. We try to identify threatening processes for each species and write a detailed report (Bird and Hodges 2017). The action plan specified can rarely be carried out because it is multi-year and expensive, so the matter rests. For many of these species at risk and for almost all that are ignored the central problem is action – what could you do about a declining species-at-risk, given funds and person-power? We do what we can on a local scale on the principle that it is better to do something than nothing (Westwood et al. 2019). But too often even if we have a good ecological understanding of declines, for example in mountain caribou in Canada, little or nothing is done (Palm et al. 2020). Conservation collides with economics.

I will try to draw a few possible conclusions out of this general discussion.

  1. It is far from clear that global biodiversity is declining rapidly.
  2. On a local level we can do careful evaluations for some species at risk and take possible action if funding is available.
  3. Setting aside large areas of habitat is currently the best immediate conservation strategy. Managing land use is critical.
  4. Designing strong monitoring programs is essential to discover population and community trends so that, if action can be taken, it is not too late.
  5. Climate change will have profound biodiversity effects in the long run, and conservation scientists must work short-term but plan long-term.

As we take actions for conservation, we ought to keep in mind the central question: What will this ecosystem look like in 100 or 200 years? Perhaps that could be a t-shirt slogan.

Bird, S.C., and Hodges, K.E. (2017). Critical habitat designation for Canadian listed species: Slow, biased, and incomplete. Environmental Science & Policy 71, 1-8. doi: 10.1016/j.envsci.2017.01.007.

Cardinale, B.J., Gonzalez, A., Allington, G.R.H., and Loreau, M. (2018). Is local biodiversity declining or not? A summary of the debate over analysis of species richness time trends. Biological Conservation 219, 175-183. doi: 10.1016/j.biocon.2017.12.021.

Dornelas, M., Gotelli, N.J., Shimadzu, H., Moyes, F., Magurran, A.E., and McGill, B.J. (2019). A balance of winners and losers in the Anthropocene. Ecology Letters 22, 847-854. doi: 10.1111/ele.13242.

Habel, J.C., Samways, M.J., and Schmitt, T. (2019). Mitigating the precipitous decline of terrestrial European insects: Requirements for a new strategy. Biodiversity and Conservation 28, 1343-1360. doi: 10.1007/s10531-019-01741-8.

Palm, E.C., Fluker, S., Nesbitt, H.K., Jacob, A.L., and Hebblewhite, M. (2020). The long road to protecting critical habitat for species at risk: The case of southern mountain woodland caribou. Conservation Science and Practice 2 (7). doi: 10.1111/csp2.219.

Vellend, M., Dornelas, M., Baeten, L., Beauséjour, R., Brown, C.D., De Frenne, P., Elmendorf, S.C., et. al. (2017). Estimates of local biodiversity change over time stand up to scrutiny. Ecology 98, 583-590. doi: 10.1002/ecy.1660.

Westwood, A.R., Otto, S.P., Mooers, A., Darimont, C., Hodges, K.E., Johnson, C., Starzomski, B. et al. (2019). Protecting biodiversity in British Columbia: Recommendations for developing species at risk legislation. FACETS 4, 136-160. doi: 10.1139/facets-2018-0042.

How Should We Test Global Models in Ecology?

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There is an understandable desire to view ecological ideas on an exceptionally large or even global scale. Just as physicists, chemists, and engineers apply their scientific results as correct everywhere, biologists would like to have global hypotheses and global models of ecological principles. There is only one problem – that ecological principles or ‘laws’ are climate contingent. This simple fact has produced a minor mode of panic in the ecological literature. How reliable are our ecological principles? Must we change them as the climate changes? In principle not, since many chemical and physical laws are temperature dependent or moisture dependent, and we just recognize that these laws have a temperature or moisture parameter as part and parcel of how things like chemical reactions can change.

This kind of argument would suggest that if we build the physical-chemical universe into our ecological models we could approach the hard sciences in predictive precision. Alas as we know this is not to be. Why not? The first argument is that ecological systems are composed of many variables – all individuals in a population are not identical, communities and ecosystems contain many interacting species with different physical and chemical requirements. But this does not necessarily let ecologists off the hook because it can be interpreted to mean that we simply have a much harder job to do and it will take much longer but it is in principle achievable. The second argument is that evolution continues to occur and is in principle unpredictable, so that while we know where we are at present, we do not know the future (Ivory et al. 2019).

Let us take a global example of the decline in coral reefs as temperature in the ocean rises. We will ignore for the moment CO2 acidity changes to keep the discussion simple. We can define closely the thermal limits of different coral species, so that should give us good predictability. But we do not know if natural selection will change these thermal limits, or whether or not it can do so rapidly enough. For the most part we project that increasing ocean temperatures will destroy most of our coral reefs and turn them into algal communities. This prediction is partly based on observations of the last 40 years in different parts of the tropics and partly based on measurements in physiological ecology in the lab. But the elephant in the prediction room is evolution and what genetic variation now exists but has not been measured, as well as how far temperature and CO2 will increase (Frank 2019).  

So ecologists are caught in a dilemma – we can in principle define the current state of ecosystems and make short term predictions that we can test with further monitoring, but we cannot make the long term predictions everyone wants to have. As conservation biologists we can make warnings but few of them would stand up in court when push comes to shove. So the consequence is that we live in a world of make believe where, for example in British Columbia the government in its wisdom says yes we must protect old growth forests, and we will do all possible to achieve this goal, as long as new policies do not reduce the annual allowable cut to the forest industry.

We can look to paleoecology to get an overview of how life on Earth has changed in the past on any time scale you wish. If there is a general law coming out of all this research it is that when climate changes, ecological communities and ecosystems change. The simple message that is hard to get across is that, if you like current environmental conditions and desire only small changes in our present ecological communities, it is desirable to reduce the pollution that is causing rapid climate change. No clever and detailed global ecological model will help us overcome the tragedies unfolding with the business as usual models we currently use unless we control rapid climate change (van der Zande et al. 2020). A current popular example is the suggestion that if we plant trees around the world, we can reverse rising CO2 level. That sounds like a good achievable plan but in fact it is impossible (Friedlingstein et al. 2019).

So, my advice is two-fold. First, design and test global ecological models for short term understanding and predictions. Do not pretend they will provide accurate long-term predictions for ecological systems. In some cases, there is little predictability (Geary et al. 2020). Second, do much more long-term monitoring of communities and ecosystems to trace local and global changes quantitatively (Wagner 2020). Then at least we will know how big the ‘wolf’ is before we ‘cry wolf’. 

Frank, P. (2019). Propagation of error and the reliability of global air temperature projections. Frontiers in Earth Science 7, 223. doi: 10.3389/feart.2019.00223.

Friedlingstein, P., Allen, M., Canadell, J.G., Peters, G.P., and Seneviratne, S.I. (2019). Comment on “The global tree restoration potential”. Science 366, eaay8060. doi: 10.1126/science.aay8060.

Geary, W.L., Doherty, T.S., Nimmo, D.G., Tulloch, A.I.T., and Ritchie, E.G. (2020). Predator responses to fire: A global systematic review and meta-analysis. Journal of Animal Ecology 89, 955-971. doi: 10.1111/1365-2656.13153.

Ivory, S. J., Russell, J., Early, R., and Sax, D.F. (2019). Broader niches revealed by fossil data do not reduce estimates of range loss and fragmentation of African montane trees. Global Ecology and Biogeography 28, 992-1003. doi: 10.1111/geb.12909.

van der Zande, R.M., Achlatis, M., Bender-Champ, D., Kubicek, A., and Dove, S. (2020). Paradise lost: End-of-century warming and acidification under business-as-usual emissions have severe consequences for symbiotic corals. Global Change Biology 26, 2203-2219. doi: 10.1111/gcb.14998.

Wagner, D.L. (2020). Insect declines in the Anthropocene. Annual Review of Entomology 65, 457-480. doi: 10.1146/annurev-ento-011019-025151.

On the Use of Statistics in Ecological Research

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There is an ever-deepening cascade of statistical methods and if you are going to be up to date you will have to use and cite some of them in your research reports or thesis. But before you jump into these methods, you might consider a few tidbits of advice. I suggest three rules and a few simple guidelines:

Rule 1. For descriptive papers keep to descriptive statistics. Every good basic statistics book has advice on when to use means to describe “average values”, when to use medians, or percentiles. Follow their advice and do not in your report generate any hypotheses except in the discussion. And follow the simple advice of statisticians not to generate and then test a hypothesis with the same set of data. Descriptive papers are most valuable. They can lead us to speculations and suggest hypotheses and explanations, but they do not lead us to strong inference.

Rule 2. For explanatory papers, the statistical rules become more complicated. For scientific explanation you need 2 or more alternative hypotheses that make different, non-overlapping predictions. The predictions must involve biological or physical mechanisms. Correlations alone are not mechanisms. They may help to lead you to a mechanism, but the key is that the mechanism must involve a cause and an effect. A correlation of a decline in whale numbers with a decline in sunspot numbers may be interesting but only if you can tie this correlation into an actual mechanism that affects birth or death rates of the whales.

Rule 3. For experimental papers you have access to a large variety of books and papers on experimental design. You must have a control or unmanipulated group, or for a comparative experiment a group A with treatment X, and a group B with treatment Y. There are many rules in the writings of experimental design that give good guidance (e.g. Anderson 2008; Eberhardt 2003; Johnson 2002; Shadish et al. 2002; Underwood 1990).

For all these ecology papers, consider the best of the recent statistical admonitions. Use statistics to enlighten not to obfuscate the reader. Use graphics to illustrate major results. Avoid p-values (Anderson et al. 2000; Ioannidis 2019a, 2019b). Measure effect sizes for different treatments (Nakagawa and Cuthill 2007). Add to these general admonitions the conventional rules of paper or report submission – do not argue with the editor, argue a small amount with the reviewers (none are perfect), and put your main messages in the abstract. And remember that it is possible there was some interesting research done before the year 2000.

Anderson, D.R. (2008) ‘Model Based Inference in the Life Sciences: A Primer on Evidence.’ (Springer: New York.). 184 pp.

Anderson, D.R., Burnham, K.P., and Thompson, W.L. (2000). Null hypothesis testing: problems, prevalence, and an alternative. Journal of Wildlife Management 64, 912-923.

Eberhardt, L.L. (2003). What should we do about hypothesis testing? Journal of Wildlife Management 67, 241-247.

Ioannidis, J.P.A. (2019a). Options for publishing research without any P-values. European Heart Journal 40, 2555-2556. doi: 10.1093/eurheartj/ehz556.

Ioannidis, J. P. A. (2019b). What have we (not) learnt from millions of scientific papers with P values? American Statistician 73, 20-25. doi: 10.1080/00031305.2018.1447512.

Johnson, D.H. (2002). The importance of replication in wildlife research. Journal of Wildlife Management 66, 919-932.

Nakagawa, S. and Cuthill, I.C. (2007). Effect size, confidence interval and statistical significance: a practical guide for biologists. Biological Reviews 82, 591-605. doi: 10.1111/j.1469-185X.2007.00027.x.

Shadish, W.R, Cook, T.D., and Campbell, D.T. (2002) ‘Experimental and Quasi-Experimental Designs for Generalized Causal Inference.’ (Houghton Mifflin Company: New York.)

Underwood, A. J. (1990). Experiments in ecology and management: Their logics, functions and interpretations. Australian Journal of Ecology 15, 365-389.

On Three Kinds of Ecology Papers

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There are many possible types of papers that discuss ecology, and in particular I want to deal only with empirical studies that deal with terrestrial and aquatic populations, communities, or ecosystems. I will not discuss here theoretical studies or modelling studies. I suggest it is possible to classify papers in ecological science journals that deal with field studies into three categories which I will call Descriptive Ecology, Explanatory Ecology, and Experimental Ecology. Papers in all these categories deal with a description of some aspects of the ecological world and how it works but they differ in their scientific impact.

Descriptive Ecology publications are essential to ecological science because they present some details of the natural history of an ecological population or community that is vital to our growing understanding of the biota of the Earth. There is much literature in this group, and ecologists all have piles of books on the local natural history of birds, moths, turtles, and large mammals, to mention only a few. Fauna and flora compilations pull much of this information together to guide beginning students and the interested public in increased knowledge of local fauna and flora. These publications are extremely valuable because they form the natural history basis of our science, and greatly outnumber the other two categories of papers. The importance of this information has been a continuous message of ecologists over many years (e.g. Bartholomew 1986; Dayton 2003; Travis 2020).

The scientific journals that professional ecologists read are mostly concerned with papers that can be classified as Explanatory Ecology and Experimental Ecology. In a broad sense these two categories can be described as providing a good story to tie together and thus explain the known facts of natural history or alternatively to define a set of hypotheses that provide alternative explanations for these facts and then to test these hypotheses experimentally. Rigorous ecology like all good science proceeds from the explanatory phase to the experimental phase. Good natural history provides several possible explanations for ecological events but does not stop there. If a particular bird population is declining, we need first to make a guess from natural history if this decline might be from disease, habitat loss, or predation. But to proceed to successful management of this conservation problem, we need studies that distinguish the cause(s) of our ecological problems, as recognized by Caughley (1994) and emphasized by Hone et al. (2018). Consequently the flow in all the sciences is from descriptive studies to explanatory ideas to experimental validation. Without experimental validation ‘ecological ideas’ can transform into ‘ecological opinions’ to the detriment of our science. This is not a new view of scientific method (Popper 1963) but it does need to be repeated (Betini et al. 2017). 

If I repeat this too much, I suggest you do a survey of how often ecological papers in your favorite journal are published without ever using the word ‘hypothesis’ or ‘experiment’. A historical survey of these or similar words would be a worthwhile endeavour for an honours or M.Sc. student in any one of the ecological subdisciplines. The favourite explanation offered in many current papers is climate change, a particularly difficult hypothesis to test because, if it is specified vaguely enough, it is impossible to test experimentally. Telling interesting stories should not be confused with rigorous experimental ecology.

Bartholomew, G. A. (1986). The role of natural history in comtemporary biology. BioScience 36, 324-329. doi: 10.2307/1310237

Betini, G.S., Avgar, T., and Fryxell, John M. (2017). Why are we not evaluating multiple competing hypotheses in ecology and evolution? Royal Society Open Science 4, 160756. doi: 10.1098/rsos.160756.

Caughley, G. (1994). Directions in conservation biology. Journal of Animal Ecology 63, 215-244. doi: 10.2307/5542

Dayton, P.K. (2003). The importance of the natural sciences to conservation. American Naturalist 162, 1-13. doi: 10.1086/376572

Hone, J., Drake, Alistair, and Krebs, C.J. (2018). Evaluating wildlife management by using principles of applied ecology: case studies and implications. Wildlife Research 45, 436-445. doi: 10.1071/WR18006.

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

Travis, Joseph (2020). Where is natural history in ecological, evolutionary, and behavioral science? American Naturalist 196, 1-8. doi: 10.1086/708765.