Author Archives: Charles Krebs

Why Ecological Understanding Progresses Slowly

Leave a reply

I begin with a personal observation spanning 65 years of evaluating ecological and evolutionary science – we are making progress but very slowly. This problem would be solved very simply in the Middle Ages by declaring this statement a heresy, followed by a quick burning at the stake. But for the most part we are more civil now, and we allow old folks to rant and rave without listening much.

By a stroke of luck, Betts et al. (2021) have reached the same conclusion, but in a more polite and nuanced way than I. So, for the whole story please read their paper, to which I will only add a footnote of a tirade to make it more personal. The question is simple and stark: Should all ecological research be required to follow the hypothetico-deductive framework of science? Many excellent ecologists have argued against this proposal, and I will offer only an empirical, inductive set of observations to make the contrary view in support of H-D science.  

Ecological and evolutionary papers can be broadly categorized as (1) descriptive natural history, (2) experimental hypothesis tests, and (3) future projections. The vast bulk of papers falls into the first category, a description of the world as it is today and in the past. The h-word never appears in these publications. These papers are most useful in discovering new species, new interactions between species, and the valuable information about the world of the past through paleoecology and the geological sciences. Newspapers and TV thrive on these kinds of papers and alert the public to the natural world in many excellent ways. Descriptive natural history in the broad sense fully deserves our support, and it provides information essential to category (2), experimental ecology, by asking questions about emerging problems, introduced pests, declining fisheries, endangered mammals and all the changing components of our natural world. Descriptive papers typically provide ideas that need follow up by experimental studies. 

Public support for science comes from the belief that scientists solve problems, and if the major effort of ecologists and evolutionary biologists is to describe nature, it is not surprising that financial support is minimal in these areas of study. The public is entertained but ecological problems are not solved. So, I argue we need more of papers (2). But we can get these only if we attack serious problems with experimental means, and this requires long-term thinking and long-term funding on a scale we rarely see in ecology. The movement at present is in the direction of big-data, technological methods of gathering data remotely to investigate landscape scale problems. If big data is considered only observational, we remain in category (1) and there is a critical need to make sure that big data projects are truly experimental, category (2) science (Lindenmayer, Likens and Franklin 2018). That this change is not happening so far is clear in Betts et al. (2021) Figure 2, which shows that very few papers in ecology journals in the last 25 years provide a clear set of multiple alternative hypotheses that they are attempting to test. If this criterion is a definition of good science, there is far less being done than we might think from the explosion of papers in ecology and evolution.

The third category of ecological and evolution papers is focused on future predictions with a view to climate change. In my opinion most of these papers should be confined to a science fiction journal because they are untestable model extrapolations for a future beyond our lifetimes. A limited subset of these could be useful is they were projecting a 5-10 year scenario that scientists could possibly test in the short term. If they are to be printed, I would suggest an appendix in all these papers of the list of assumptions that must be made to reach their future predictions.

There is of course the fly in the ointment that even when ecologists diagnose a conservation problem with good experiments and analysis the policy makers will not follow their advice (e.g. Palm et al. 2020). The world is not yet perfect.

Betts, M.G., Hadley, A.S., Frey, D.W., Frey, S.J.K., Gannon, D., et al. (2021). When are hypotheses useful in ecology and evolution? Ecology and Evolution. doi: 10.1002/ece3.7365.

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.

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: e219. doi: 10.1111/csp2.219.

On Declining Insect Populations

4 Replies

Judy Myers, Charles Krebs, Gergana Daskalova and Isla Myers-Smith

The rising concern about conservation issues is echoed in recent months by newspaper reports of collapses in insect populations world-wide: the “insect Armageddon”. As part of our general concern that the-devil-is-in-the-details, we want to discuss these reports within the general question of how we decide if this simple statement is correct or not, and what methods are needed to establish declining population trends.

We require four procedures to decide if a population or a series of populations are declining:

(1) Reliable census methods and appropriate statistical analyses must be used. This is not a trivial exercise. Results can be biased by the chance occurrence of particularly high numbers at the beginning of the data trend as in Seibold et al. (2019), the failure to correct for temporal pseudoreplication in data sets as pointed out by Daskalova et al. (2021) or by searching the literature only for studies of insect decline and then claiming to show widespread population declines as in Sánchez-Bayo et al. (2019). It is important to avoid biasing data toward a conclusion that declines are occurring. Increasing trends and examples showing no trend must be acknowledged and published to allow a true assessment.

(2) The taxonomic group of concern must be delineated since what applies to butterflies may or may not apply to carabid beetles. It can be difficult and time consuming to sort through samples to identify taxonomic groups. For this reason, the biomass of trap collections has been used as a surrogate for insect numbers in some studies (Hallman et al. 2019). This tells us nothing about population trends or diversity of different types of insects. Population data are required, and the biology of the focus group identified when considering causal mechanisms for population trends. For example, aquatic and terrestrial species are likely to respond to different environmental conditions and these must be separated (Van Klink et al., 2020).

(3) The scale of the study must be carefully outlined, whether it is 1 ha of grassland, a region, a country, or a continent. Lumping together results from studies done at different scales makes interpretation impossible. Accounting for scale in analyses is challenging, but detected trends in metrics such as species richness can differ markedly across scales (Vellend et al. 2017; Chase et al. 2019).

(4) The duration of the study must be related to the generation time of the insect group and population dynamics of those taxa. Many insects have a single generation a year and others multiple generations. Shorter time series are more variable (Daskalova et al. 2021), time trends in many insect populations are often more saw shaped than linear (Macgregor et al. 2019), and some insect species experience outbreaks or population cycles (Myers and Cory 2013).

These four requirements are not new, and many authors have discussed the details of these issues and how they play out in specific insect populations (Didham et al. 2020; Wagner 2020). A fifth requirement needs to be added when multiple studies are included in meta-analyses:

(5) All data inclusion must be scrutinized to determine if the four above requirements have been met before they are included in the meta-analysis.

Census methods for insect populations were presented long ago by Southwood (1966) in a classic book, updated in Southwood and Henderson (2000) and now reviewed recently in Montgomery et al. (2021). Montgomery et al. (2021) noted that even at this late date there is a general lack of standardization in insect monitoring methods, and that this standardization is essential if we are to track insect population or community changes. Statistical methods for time series data must be rigorous as pointed out by Daskalova et al. (2021).  The general message is that there is no one insect monitoring method that can apply to all species, and the scale of the study, along with the sampling effort needed for reliable inferences on population trends, must be decided well in advance of starting a monitoring study.

Newspaper articles dramatize the collapse of insect populations while the reality shown by detailed studies is much more nuanced. Much of the decline in insects could be traced to climate change, agricultural intensification, forestry, human population growth, urbanization and other factors (Wagner 2021). Consequently, it is important to state what the baseline for any evaluation is. The pure ecologist may wish to know how much insect populations have changed in areas where only one factor like climate change has operated. The agricultural insect ecologist may wish to know overall changes in the presence of all human and natural changes in the agricultural landscapes in which insects live (Laussmann et al. 2021). To find out the actual mechanisms behind the observed declines, a clear experimental protocol is necessary. As useful as monitoring is by itself, it can only provide weak evidence of mechanisms responsible for insect declines.

The restoration of individual species that are declining is more difficult than we might like. Warren et al. (2021) provide details of management changes that attempt to restore populations of the endangered British butterfly Hamearis lucina by landscape level habitat improvements. Funds for restoration will not be available at the scale needed for tropical and subtropical habitats losing insect diversity under stress from agricultural intensification (Raven and Wagner 2021).

The bottom line is that there are enough data now to be concerned about insect declines, but we must be careful not to cry that the “sky is falling” (Saunders et al. 2020). As in many issues with changes in populations and communities, census methods and experimental designs must be sharpened and standardized. Our take-home message is that any tests of insect population, abundance or biodiversity trends require rigorous methods of analysis before publication, or phoning the local newspaper.

Daskalova, G.N., A.B. Phillimore, and I.H. Myers‐Smith. 2021. Accounting for year effects and sampling error in temporal analyses of invertebrate population and biodiversity change: a comment on Seibold et al. 2019. Insect Conservation and Diversity 14:149-154. doi: 10.1111/icad.12468.

Didham, R.K., Basset, Y., Collins, C.M., Leather, S.R., et al. (2020). Interpreting insect declines: seven challenges and a way forward. Insect Conservation and Diversity 13, 103-114. doi: 10.1111/icad.12408.

Chase, J.M., McGill, B.J., Thompson, P.L., Antão, L.H., Bates, A.E., et al. 2019. Species richness change across spatial scales. Oikos 128:1079-1091. doi: 10.1111/oik.05968

Hallmann, C.A., et al. 2017. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS ONE 12, e0185809. doi: 10.1371/journal.pone.0185809

Laussmann, T., Dahl, A., Radtke, A., 2021. Lost and found: 160 years of Lepidoptera observations in Wuppertal (Germany). Journal of Insect Conservation (in press). doi: 10.1007/s10841-021-00296-w

Macgregor, C.J., J. H. Williams, J.R. Bell, and C.D. Thomas. 2019. Moth biomass increases and decreases over 50 years in Britain. Nature Ecology & Evolution 3:1645-1649. doi: 10.1038/s41559-019-1028-6

Montgomery, G.A., M.W. Belitz, R.P. Guralnick, and M.W. Tingley. 2021. Standards and best practices for monitoring and benchmarking insects. Frontiers in Ecology and Evolution 8: 579193. doi: 10.3389/fevo.2020.579193.

Myers, J.H., Cory, J.S., 2013. Population cycles in forest Lepidoptera revisited. Annual Review of Ecology, Evolution, and Systematics 44, 565–592. https://doi.org/10.1146/annurev-ecolsys-110512-135858

Raven, P. H., and D. L. Wagner. 2021. Agricultural intensification and climate change are rapidly decreasing insect biodiversity. Proceedings of the National Academy of Sciences 118 (2): e2002548117. doi: 10.1073/pnas.2002548117. 

Sánchez-Bayo, F., and K. A. Wyckhuys. 2019. Worldwide decline of the entomofauna: A review of its drivers. Biological Conservation 232:8-27. doi: 10.1016/j.biocon.2019.01.020

Saunders, M.E., Janes, J.K. and O’Hanlon, J.C., 2020. Moving on from the insect apocalypse narrative: Engaging with evidence-based insect conservation. BioScience, 70(1):80-89. doi: 10.1093/biosci/biz143

Seibold, S., M. M. Gossner, N. K. Simons, N. Blüthgen, et. al. 2019. Arthropod decline in grasslands and forests is associated with landscape-level drivers. Nature 574:671-674. doi: 10.1038/s41586-019-1684-3.

Southwood, T.R.E. (1966) ‘Ecological Methods.’ (Methuen: London.)

Southwood, T.R.E. and Henderson, P.A. (2000) ‘Ecological Methods.’ (Blackwell Science: Oxford.) 575 pp.  ISBN: 0632054778

van Klink, R., Bowler, D.E., Gongalsky, K.B., Swengel, A.B., et al. (2020). Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances. Science 368, 417-420. doi: 10.1126/science.aax9931.

Vellend, M., Baeten, L., Becker-Scarpitta, A., Boucher-Lalonde, V., McCune, J.L., Messier, J., Myers-Smith, I.H. and Sax, D.F., 2017. Plant biodiversity change across scales during the Anthropocene. Annual Review of Plant Biology 68:563-586. doi: 10.1146/annurev-arplant-042916-040949 .

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

Wagner, D.L., Grames, E.M., Forister, M.L., Berenbaum, M.R., and Stopak, D. (2021). Insect decline in the Anthropocene: Death by a thousand cuts. Proceedings of the National Academy of Sciences 118, e2023989118. doi: 10.1073/pnas.2023989118.

Warren, M.S., et al. (2021). The decline of butterflies in Europe: Problems, significance, and possible solutions. Proceedings of the National Academy of Sciences 118 (2), e2002551117. doi: 10.1073/pnas.2002551117.

On Innovative Ecological Research

1 Reply

Ecological research should have an impact on policy development. For the most part it does not. You do not need to take my word for this, since I am over the age of 40, so for confirmation you might read the New Zealand Environmental Science Funding Review (2020) which stated:

“I am not confident that there is a coherent basis for our national investment in environmental science. I am particularly concerned that there is no mechanism that links the ongoing demand environmental reporting makes for an understanding of complex ecological processes that evolve over decades, and a science funding system that is constantly searching for innovation, impact and linkages to the ever-changing demands of business and society.” (page 3)

Of course New Zealand may be an outlier, so we must seek confirmation in the Northern Hemisphere. Bill Sutherland and his many colleagues has every 3-4 years since 2006 (nearly in concert with the lemming cycle) put out an extraordinary array of suggestions for important ecological questions that need to be answered for conservation and management. If you should be running a seminar this year, you might consider doing a historical survey of how these suggestions have changed since 2006, 2010, 2013, to 2018. Excellent questions, and how much progress has there been on answering his challenges?

Some progress to be sure, and for that we are thankful, but the problems multiply faster than ecological progress, and I am reminded of trying to stop a snow avalanche with a shovel. Why should this be? There are some very big questions in ecology that we need to answer but my first observation is that we have made little progress with the Sutherland et al. (2006) list, which would be largely culled from the previous many years of ecological studies. The first problem is that research funding is too often geared to novel and innovative proposals, so that if you would ask for funding to answer an old question that Charles Elton proposed in the 1950s, you would be struck off the list of innovative ecologists and possibly exiled to Mars with Elon Musk. Innovation in the mind of the granting agencies is based on the iPhone and the latest models of cars which have a time scale of one year. Any ecologist working on a problem that has a time scale of 30 years is behind the times. So when you write a grant request proposal you are pushed to restate the problems recognized long ago as though they were newly recognized with new methods of analysis.

There is no doubt some truly innovative ecological research, and to list these might be another interesting seminar project, but most of the environmental problems of our day are very old problems that remain unresolved. Government agencies in some countries have a list of problems of the here-and-now that university research rarely focuses on because the research cannot be innovative. These mostly practical problems must then be solved by government environmental departments with their ever-shrinking resources, so they in turn contract these out to the private sector with its checkered record of gathering the data required for solving the problems at hand.

Environmental scientists will complain that when they do reach conclusions that will at least partly resolve the problems of the day, governments refuse to act on this knowledge because of a variety of vested interests; if the environment wins, the vested interests lose, not a zero-sum game. If you want a good example, note that John Tyndall recognized CO2 and the Greenhouse Effect in 1859, and Svante Arrhenius and Thomas Chamberlin calculated in 1896 that burning fossil fuels increased CO2 such that 2 X CO2 would = + 5ºC rise in temperature. And in 2021 some people still argue about this conclusion.

My suggestion is that we would be better off striking the word ‘innovation’ from all our granting councils and environmental research funding organizations, and replacing it with ‘excellent’ and ‘well designed’ as qualities to support. You are still allowed to talk about ‘innovative’ iPhones and autos, but we are better off with ‘excellent’ environmental and ecological research.

New Zealand Parliamentary Commissioner for the Environment. (2020). A review of the funding and prioritisation of environmental research in New Zealand (Wellington, New Zealand.) Available online: https://www.pce.parliament.nz/publications/environmental-research-funding-review

Sutherland, W.J., et al. (2006). The identification of 100 ecological questions of high policy relevance in the UK. Journal of Applied Ecology 43, 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, 1-7. doi: 10.1016/j.tree.2009.10.003

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

Sutherland, W.J., et al. (2018). A 2018 Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity. Trends in Ecology & Evolution 33, 47-58. doi: 10.1016/j.tree.2017.11.006.

On the Focus of Biodiversity Science

Leave a reply

Biodiversity science has expanded in the last 25 years to include scientific disciplines that were in a previous time considered independent disciplines. Now this could be thought of as a good thing because we all want science to be interactive, so that geologists talk to ecologists who also talk to mathematicians and physicists. University administrators might welcome this movement because it could aim for a terminal condition in which all the departments of the university are amalgamated into one big universal science department of Biodiversity which would include sociology, forestry, agriculture, engineering, fisheries, wildlife, geography, and possibly law and literature as capstones. Depending on your viewpoint, there are a few problems with this vision or nightmare that are already showing up.

First and foremost is the problem of the increasing amount of specialist knowledge that is necessary to know how to be a good soil scientist, or geographer, or fisheries ecologist. So if we need teams of scientists working on a particular problem, there must be careful integration of the parts and a shared vision of how to reach a resolution of the problem. This is more and more difficult to achieve as each individual science itself becomes more and more specialized, so that for example your team now needs a soil scientist who specializes only in clay soils. The results of this problem are visible today with the Covid pandemic, many research groups working at odds to one another, many cooperating but not all, vaccine supplies being restricted by politics and nationalism, some specialists claiming that all can be cured with hydroxychloroquine or bleach. So the first problem is how to assemble a team. If you want to do this, you need to sort out a second issue.

The second hurdle is another very big issue upon which there is rarely good agreement: What are the problems you wish to solve? If you are a university department you have a very restricted range of faculty, so you cannot solve every biodiversity problem on earth. At one extreme you can have the one faculty member = one problem approach, so one person is concerned with the conservation of birds on mountain tops, another is to study frogs and salamanders in southern Ontario, and a third is to be concerned about the conservation of rare orchids in Indonesia. At the other extreme is the many faculty = one problem approach where you concentrate your research power on a very few issues. Typically one might think these should be Canadian issues if you were a Canadian university, or New Zealand issues if you were a New Zealand university. In general many universities have taken the first approach and have assumed that government departments will fill in the second approach by concentrating on major issues like fisheries declines or forest diseases.

Alas the consequences of the present system are that the government is reducing its involvement in solving large scale issues (take caribou in Canada, the Everglades in Florida, or house mice outbreaks in Australia). At the same time university budgets are being cut and there is less and less interest in contributing to the solution of environmental problems and more and more interest in fields that increase economic growth and jobs. Universities excel at short term challenges, 2–3-year problem solving, but do very poorly at long-term issues. And it is the long term problems that are destroying the Earth’s ecosystems.

The problem facing biodiversity science is exactly that no one wishes to concentrate on a single major problem, so we drift in bits and pieces, missing the chance to make any significant progress in any one of the major issues of our day. Take any major issue you wish to discuss. How many species are there on Earth? We do not even know that very well except in a few groups, so how much effort must go into taxonomy? Are insect populations declining? Data are extremely limited to a few groups gathered over a small number of years in a small part of the Earth with inadequate sampling. Within North America, why are charismatic species like monarch butterflies declining, or are they really declining? How much habitat must be protected to ensure the continuation of a migratory species like this butterfly. Can we ecologists claim that any one of our major problems are being resourced adequately to discover answers?

When biodiversity science interfaces with agricultural science and the applied sciences of fisheries and wildlife management we run into another set of major questions. Is modern agriculture sustainable? Certainly not, but how can we change it in the right direction? Are pelagic fisheries being overharvested? Questions abound, answers are tentative and need more evidence. Is biodiversity science supposed to provide solutions to these kinds of applied ecological questions? The current major question that appears in most biodiversity papers is how will biodiversity respond to climate change?  This is in principle a question that can be answered at the local species or community scale, but it provides no resolution to the problem of biodiversity loss or indeed even allows adequate data gathering to map the extent and reality of loss. Are we back to mapping the chairs on the Titanic but now with detailed satellite data?

What can be done about this lack of focus in biodiversity science? At the broadest level we need to increase discussions about what we are trying to accomplish in the current state of scientific organization. Trying to write down the problems we are currently studying and then the possible ways in which the problem can be resolved would be a good start. If we recognize a major problem but then can see no possible way of resolving it, perhaps our research or management efforts should be redirected. But it takes great courage to say here is a problem in biodiversity conservation, but it can never be solved with a finite budget (Buxton et al. 2021). So start by asking: why am I doing this research, and where do I think we might be in 50 years on this issue? Make a list of insoluble problems. Here is a simple one to start on: eradicating invasive species. Perhaps eradication can be done in some situations like islands (Russell et al. 2016) but is impossible in the vast majority of cases. There may be major disagreements over goals, in which case some rules might be put forward, such as a budget of $5 million over 4 years to achieve the specified goal. Much as we might like, biodiversity conservation cannot operate with an infinite budget and an infinite time frame.

Buxton, R.T., Nyboer, E.A., Pigeon, K.E., Raby, G.D., and Rytwinski, T. (2021). Avoiding wasted research resources in conservation science. Conservation Science and Practice 3. doi: 10.1111/csp2.329.

Russell, J.C., Jones, H.P., Armstrong, D.P., Courchamp, F., and Kappes, P.J. (2016). Importance of lethal control of invasive predators for island conservation. Conservation Biology 30, 670-672. doi: 10.1111/cobi.12666.

On the Dollar Value of Nature

Leave a reply

The Dasgupta Report was released last week with great promise. The news outlets were happy: The Guardian newspaper for example reported:

“The world is being put at “extreme risk” by the failure of economics to take account of the rapid depletion of the natural world and needs to find new measures of success to avoid a catastrophic breakdown, a landmark review has concluded.

Prosperity was coming at a “devastating cost” to the ecosystems that provide humanity with food, water and clean air, said Prof Sir Partha Dasgupta, the Cambridge University economist who conducted the review.

The 600-page review was commissioned by the UK Treasury, the first time a national finance ministry has authorised a full assessment of the economic importance of nature.”

What should we make of this scenario? Are ecologists happy that economists now think all the things we have been fighting for are finally recognized? Or are we barking up the wrong tree? The first assumption is that we have surrendered all environmental decision making to economists. A corollary of this assumption might be that we tried having David Attenborough and the many excellent nature presenters convince the world that nature is wonderful and should be kept for all to enjoy, and this has mostly failed to alleviate our environmental problems. Many people do not seem to really care about nature unless it affects their livelihood directly. A second assumption is that economics is king of all, and by rolling out the big guns we will finally get progress in resolving environmental problems. Forget studying ecology and take up economics instead. If these two assumptions are correct, I would propose that we have lost the plot, and if we can deal with our ecological mess only by talking dollars, we really are lost.

Many people believe that we can overcome environmental changes and at the same time carry on much as we are today. The ever-increasing number of sustainability institutes and journals will attest to the reversal of environmental damage. Unfortunately, the correlation is positive rather than negative, and as this and many other reports detail, environmental damages continue to increase and at an increasing rate. What can we do to change this?

The first problem is that the environmental mess accumulates at too slow a rate, so the simplest solution for each person is to live by the maxim “I will pass away soon anyway, so why bother”. That does not help our children, and the next convenient viewpoint is that technology will save us. It is quite clear that technology will entertain us, but there are legitimate doubts that technology can be relied on for environmental salvation.

The nub of our problem is that we live in a world that has no leader. There certainly are leaders good and bad in many countries, but there is no supreme leader who can tell all the world’s peoples to act sustainably, and to be the police chief if they do not (Mearsheimer 2018). So burn coal if you wish, and mine coal even if people complain, and spread pollution as your individual right in spite of the clear rules of sustainable living. And the key is that you can ban mining and burning coal in one advanced country, but you have no power to tell other countries that they must do the same for the good of the Earth.   

When Nicholas Stern in 2006 released his 692-page report on the effect of global warming on the world’s economy, he summarized it this way:

  • there is still time to avoid the worst impacts of climate change, if we take strong action now
  • climate change could have very serious impacts on growth and development
  • the costs of stabilising the climate are significant but manageable; delay would be dangerous and much more costly
  • action on climate change is required across all countries, and it need not cap the aspirations for growth of rich or poor countries
  • a range of options exists to cut emissions; strong, deliberate policy action is required to motivate their take-up
  • climate change demands an international response, based on a shared understanding of long-term goals and agreement on frameworks for action.

The comments of some of the reviewers echoed that “the Stern Review was critically important in moving the climate issue from one of science to one of economics”. The Dasgupta Report of 2021 devotes 606 pages to the economics of biodiversity and perhaps will be lauded as moving the biodiversity issue from the realm of science to the realm of economics. The realms of science and of economics are intertwined, as the current Covid epidemic illustrates all too well. But I think it is a mistake to convert human beings into Homo oeconomicus because the world of biodiversity should not be worthy of protection solely because of its economic value to humans. There are many values that are of higher importance than economic values.

It is nevertheless important to align economic policies with biodiversity protection, and there is already an enormous literature discussing this from one extreme (Gray and Milne 2018) to another (Maron et al. 2018). Ecologists have tried mightily to incorporate our ecological world view into the economic realities but with only limited success (Constanza et al. 2017). The history of human treatment of nature is not very inviting to consider, and I do not like to project the past linearly on the future. But even in this pandemic one sees too many people who ignore all reasonable requests to alleviate problems, and the political systems of our day are so weak when it comes to protecting nature that most policy people seem to think that protecting a few small parks and reserves is enough. We certainly value the David Attenborough presentations on our TV but the need for real world responses seems muted and very slow to develop. I fear that economic science will do little better than biodiversity science to stop the juggernaut, but I hope to be wrong. To date the Titanic paradigm fits the facts too closely. If you are optimistic, go back and read the Stern Report of 2006 and then the Dasgupta Report of 2021. Progress?

Costanza, R., et al. (2017). Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem Services 28, 1-16. doi: 10.1016/j.ecoser.2017.09.008.

Dasgupta, P. (2021) The Economics of Biodiversity: The Dasgupta Review. (London: HM Treasury. Available at: www.gov.uk/official-documents.

Gray, R. and Milne, M.J. (2018). Perhaps the Dodo should have accounted for human beings? Accounts of humanity and (its) extinction. Accounting, Auditing, & Accountability 31, 826-848. doi: 10.1108/AAAJ-03-2016-2483.

Maron, M., et al. (2018). The many meanings of No Net Loss in environmental policy. Nature Sustainability 1, 19-27. doi: 10.1038/s41893-017-0007-7.

Mearsheimer, J.J. (2018) ‘The Great Delusion: Liberal Dreams and International Realities.’ (Yale University Press: New Haven.). ISBN: 978-0-300-24856-2

Stern, N. (2006). The Economics of Climate Change: The Stern Review. (London: HM Treasury). ISBN number: 0-521-70080-9 (Cambridge University Press, 2007).

On the Bonn Challenge: Tree Restoration and the Climate Emergency

3 Replies

“Plant a tree and save the world” is the short version of the Bonn Challenge of 2011 and the UN Decade of Ecosystem Restoration 2021-2030 (Stanturf and Mansourian 2020), and so here we are with a major ecological challenge for the decade we have just started. Planting trees around the world to restore 350 million hectares of degraded land is the goal, and it is a challenge that ecologists must think clearly about to avoid failure of another grand scheme.

Restoring ecosystems is not easy as we have already learned to our dismay. What began as a relatively simple restoration of old fields used in agriculture, a few hectares of ploughed ground surrounded by forest or grassland, has now morphed into very large areas devastated by forest fires, insect outbreaks, or drought. The largest forest fires in Arizona prior to the year 2000 were 20,000 ha, but after prolonged drought by 2020 they have reached nearly 300,000 ha (Falk 2017). The larger and more severe the fire, the greater the distance seed must disperse to recolonize burnt areas, and hence the recovery from large fires differs dramatically from the recovery from small or patchy fires.

I concentrate here on forest restoration, but always with the caveat in mind that the trees are not the forest – there are a plethora of other species involved in the forest ecosystem (Temperton et al. 2019). The restoration of forest landscapes is driven by the estimate that forest originally covered about 5.9 billion ha of the Earth but at the present time there is about 4 billion ha of forest remaining. Restoration of degraded ecosystems has always been a good idea, and this program can now be tied in with the climate emergency. New trees will remove CO2 from the air as they grow so we can score 2 points with every tree we plant (Bernal and Pearson 2018).  

The scale of plans for the UN Decade of Ecosystem Restoration 2021-2030 are challenging and Stanturf and Mansourian (2020) provide current details country by country. For example, Brazil a country of 836 million ha has pledged to restore 12 million ha (1.44%), with some countries like Spain and Russia so far not pledging any Bonn Challenge restoration. The take-up of actual restoration is uneven globally. The USA has committed to restore 12 million ha to the Bonn Challenge, but Canada has made no formal commitment, although the federal government has proposed to plant 2 billion trees during this decade to counteract climate change.  

Many problems arise with every ecological restoration. Not the least is the time frame of the recovery of damaged ecosystems. Forests recover slowly even when carefully tended, and 100 years might be a partial target for temperate forests. For North American west-coast forests a 400+-year time frame might be a target. Most private companies and governments can not even conceive of this scale of time. For those who think everything should work faster than this, Moreno-Mateos et al. (2020) report a large sample of >600 restored wetlands that recovered to only 74% of the target value in 50-100 years. Schmid et al. (2020) found that the microbial community of a lignite mine in Germany had not recovered to the control level even after 52 years. Ecological time does not always conform readily to industrial time.

Other constraints blur the grand global picture. Restoration with trees should not be done on tropical grasslands because of their inherent biodiversity values (c.f. Silveira et al. 2020 for excellent examples), nor can we restore trees on rangeland that is used for agricultural production lest we engage in robbing agricultural Peter to pay forester Paul (Vetter 2020). These important ecological critiques must be incorporated into country-wide plans for reforestation whose primary aim might be CO2 capture. Again the devil is in the details, as Vetter (2020) clearly articulates.  

The Bonn Challenge remains ongoing, waiting for another review after 2030. Who will remember what was promised, and who will be given the awards for achievements reached? What quantitative goals exactly have been promised, and what happens if they slip to 2050 or 2070?  

Bernal, B., Murray, L.T., and Pearson, T.R.H. (2018). Global carbon dioxide removal rates from forest landscape restoration activities. Carbon Balance and Management 13, 22. doi: 10.1186/s13021-018-0110-8.

Bonnesoeur, V., Locatelli, B., Guariguata, M.R., Ochoa-Tocachi, B.F., Vanacker, V. et al. (2019). Impacts of forests and forestation on hydrological services in the Andes: A systematic review. Forest Ecology and Management 433, 569-584. doi: 10.1016/j.foreco.2018.11.033.

Falk, Donald A. (2017). Restoration ecology, resilience, and the axes of change. Annals of the Missouri Botanical Garden 102, 201-216, 216. doi: 10.3417/2017006.

Moreno-Mateos, D., et al. (2020). The long-term restoration of ecosystem complexity. Nature Ecology & Evolution 4, 676-685. doi: 10.1038/s41559-020-1154-1.

Silveira, F.A.O., Arruda, A.J., Bond, W., Durigan, G., Fidelis, A., et al. (2020). Myth-busting tropical grassy biome restoration. Restoration Ecology 28, 1067-1073. doi: 10.1111/rec.13202.

Stanturf, J.A. and Mansourian, S. (2020). Forest landscape restoration: state of play.
Royal Society Open Science 7, 201218. doi: 10.1098/rsos.201218.

Temperton, V.M., Buchmann, N., Buisson, E., Durigan, G. and Kazmierczak, L. (2019). Step back from the forest and step up to the Bonn Challenge: how a broad ecological perspective can promote successful landscape restoration. Restoration Ecology 27, 705-719. doi: 10.1111/rec.12989.

Vetter, S. (2020). With Power Comes Responsibility – A rangelands perspective on forest landscape restoration. Frontiers in Sustainable Food Systems 4, 549483. doi: 10.3389/fsufs.2020.549483.

On an Experimental Design Mafia for Ecology

2 Replies

Ecologist A does an experiment and publishes Conclusions G and H. Ecologist B reads this paper and concludes that A’s data support Conclusions M and N and do not support Conclusions G and H. Ecologist B writes to Journal X editor to complain and is told to go get stuffed because Journal X never makes a mistake with so many members of the Editorial Board who have Nobel Prizes. This is an inviting fantasy and I want to examine one possible way to avoid at least some of these confrontations without having to fire all the Nobel Prize winners on the Editorial Board.

We go back to the simple question: Can we agree on what types of data are needed for testing this hypothesis? We now require our graduate students or at least our Nobel colleagues to submit the experimental design for their study to the newly founded Experimental Design Mafia for Ecology (or in French DEME) who will provide a critique of the formulation of the hypotheses to be tested and the actual data that will be collected. The recommendations of the DEME will be nonbinding, and professors and research supervisors will be able to ignore them with no consequences except that the coveted DEME icon will not be able to be published on the front page of the resulting papers.

The easiest part of this review will be the data methods, and this review by the DEME committee will cover the current standards for measuring temperature, doing aerial surveys for elephants, live-trapping small mammals, measuring DBH on trees, determining quadrat size for plant surveys, and other necessary data collection problems. This advice alone should hypothetically remove about 25% of future published papers that use obsolete models or inadequate methods to measure or count ecological items.

The critical part of the review will be the experimental design part of the proposed study. Experimental design is important even if it is designated as undemocratic poppycock by your research committee. First, the DEME committee will require a clear statement of the hypothesis to be tested and the alternative hypotheses. Words which are used too loosely in many ecological works must be defended as having a clear operational meaning, so that idea statements that include ‘stability’ or ‘ecosystem integrity’ may be questioned and their meaning sharpened. Hypotheses that forbid something from occurring or allow only type Y events to occur are to be preferred, and for guidance applicants may be referred to Popper (1963), Platt (1964), Anderson (2008) or Krebs (2019). If there is no alternative hypothesis, your research plan is finished. If you are using statistical methods to test your hypotheses, read Ioannidis (2019).

Once you have done all this, you are ready to go to work. Do not be concerned if your research plan goes off target or you get strange results. Be prepared to give up hypotheses that do not fit the observed facts. That means you are doing creative science.

The DEME committee will have to be refreshed every 5 years or so such that fresh ideas can be recognized. But the principles of doing good science are unlikely to change – good operational definitions, a set of hypotheses with clear predictions, a writing style that does not try to cover up contrary findings, and a forward look to what next? And the ecological world will slowly become a better place with fewer sterile arguments about angels on the head of a pin.

Anderson, D.R. (2008) ‘Model Based Inference in the Life Sciences: A Primer on Evidence.‘ (Springer: New York.) ISBN: 978-0-387-74073-7.

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

Krebs, C.J. (2020). How to ask meaningful ecological questions. In Population Ecology in Practice. (Eds D.L. Murray and B.K. Sandercock.) Chapter 1, pp. 3-16. Wiley-Blackwell: Amsterdam. ISBN: 978-0-470-67414-7

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

Popper, K. R. (1963) ‘Conjectures and Refutations: The Growth of Scientific Knowledge.’ (Routledge and Kegan Paul: London.). ISBN: 9780415285940

On Logging Old Growth Forests

4 Replies

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?

Leave a reply

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

4 Replies

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.