Category Archives: Conservation Biology

On the Dollar Value of Nature

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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

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“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 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.

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 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.

On Ecological Models and the Coronavirus

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We are caught up now in a coronavirus pandemic with an unknown end point. There is a great deal now available about COVID-19, and I want to concentrate on the models of this pandemic that currently fill our media channels. In particular I want to use the current situation to reflect on the role of mathematical models in helping to solve ecological problems and make predictions of future trends. To oversimplify greatly, the scientific world is aligned along an axis from those supporting simple models to those tied up in complex multifactor models. To make this specific, the simple epidemic model approach provides us with a coronavirus model that has three classes of actors – susceptible, infected, and recovered individuals, and one key parameter, the relative infection rate of one person to another. If you as an infected person pass on the disease to more than one additional person, the pandemic will grow. If you pass the disease on to less than one person (on average), the pandemic will collapse. Social distancing will flip us into the favourable state of declining infections. There is a similar sort of model in ecology for predator-prey interactions, called the Lotka-Volterra model, in which one predator eating one prey species will change the population size of both depending on the rate of killing of the predator and the rate of reproduction of the prey.

So far so good. We can all have an intuitive understanding of such simple models, but of course the critics rise up in horror with the cry that “the devil is in the details”. And indeed this is also a universal truth. All humans are not equally affected by COVID-19. Older people do poorly, young children appear to be little bothered by the virus. All prey individuals in nature are also not equally susceptible to being caught by a predator. Young prey may not run as fast as adults, poorly fed prey in winter may run more slowly than well fed animals. The consequences of this ‘inequality’ is what leads to the need for an increasing investment in scientific research. We can pretend the world is simple and the virus will just “go away”, and a simple view of predation that “larger animals eat smaller animals” could fail to recognize that a small predator might drive a dinosaur species extinct if the small predator eats only the eggs of the prey and avoids the big adults. The world is complicated, and that is what makes it both interesting to many and infuriating to some who demand simplicity.

One of the purposes of a mathematical model is to allow predictions of coming events, and we hear much of this with the COVID-19 models currently in circulation. A simple principle is “all models are wrong’ but this must be matched with the corollary that in general “the simpler the model the more likely it is to provide poor forecasts. But there is a corollary that might be called the “Carl Walters’ Law” that there is some optimal level of complexity for a good result, and too much complexity is also a recipe for poor projections. The difficulty is that we can often only find this optimal point after the fact, so that we learn by doing. This does not sit well with politicians and business-people who demand “PRECISE PRECISION PROMPTLY!” 

These uncertainties reflect on to our current decision making in the coronavirus pandemic, in issues to fight climate change, and in the conservation of threatened species and ecosystems. Our models, our scientific understanding, and our decisions are never perfect or complete, and as we see so clearly with COVID-19 the science in particular can be pushed but cannot be rushed, even when money is not limiting. The combination of planning, judgement and knowledge that we call wisdom may come more slowly than we wish. Meanwhile there are many details that need investigation.  

Adam, D. (2020) Modelling the Pandemic: The simulations driving the world’s response to COVID-19. Nature, 580, 316-318. Doi: 10.1038/d41586-020-01003-6 

Neher, R.A., Dyrdak, R., Druelle, V., Hodcroft, E.B. & Albert, J. (2020) Potential impact of seasonal forcing on a SARS-CoV-2 pandemic. Swiss Medical Weekly 150, w20224. Doi: 10.4414/smw.2020.20224.

Xu, B., Cai, J., He, D., Chowell, G. & Xu, B. (2020) Mechanistic modelling of multiple waves in an influenza epidemic or pandemic. Journal of Theoretical Biology, 486, 110070. Doi: 10.1016/j.jtbi.2019.110070.

On Declining Bird Populations

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The conservation literature and the media are alive with cries of declining bird populations around the world (Rosenberg et al. 2019). Birds are well liked by people, and an important part of our environment so they garner a lot of attention when the cry goes out that all is not well. The problems from a scientific perspective is what evidence is required to “cry wolf’. There are many different opinions on what data provide reliable evidence. There is a splendid critique of the Rosenberg et al paper by Brian McGill that you should read::
https://dynamicecology.wordpress.com/2019/09/20/did-north-america-really-lose-3-billion-birds-what-does-it-mean/

My object here is to add a comment from the viewpoint of population ecology. It might be useful for bird ecologists to have a brief overview of what ecological evidence is required to decide that a bird population or a bird species or a whole group of birds is threatened or endangered. One simple way to make this decision is with a verbal flow chart and I offer here one example of how to proceed.

  1. Get accurate and precise data on the populations of interest. If you claim a population is declining or endangered, you need to define the population and know its abundance over a reasonable time period.

Note that this is already a nearly impossible demand. For birds that are continuously resident it is possible to census them well. Let me guess that continuous residency occurs in at most 5% or fewer of the birds of the world. The other birds we would like to protect are global or local migrants or move unpredictably in search of food resources, so it is difficult to define a population and determine if the population as a whole is rising or falling. Compounding all this are the truly rare bird species that are difficult to census like all rare species. Dorey and Walker (2018) examine these concerns for Canada.

The next problem is what is a reasonable time period for the census data. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) gives 10 years or 3 generations, whichever is longer (see web link below). So now we need to know the generation time of the species of concern. We can make a guess at generation time but let us stick with 10 years for the moment. For how many bird species in Canada do we have 10 years of accurate population estimates?

  • Next, we need to determine the causes of the decline if we wish to instigate management actions. Populations decline because of a falling reproductive rate, increasing death rate, or higher emigration rates. There are very few birds for which we have 10 years of diagnosis for the causes of changes in these vital rates. Strong conclusions should not rest on weak data.

The absence of much of these required data force conservation biologists to guess about what is driving numbers down, knowing only that population numbers are falling. Typically, many things are happening over the 10 years of assessment – climate is changing, habitats are being lost or gained, invasive species are spreading, new toxic chemical are being used for pest control, diseases are appearing, the list is long. We have little time or money to determine the critical limiting factors. We can only make a guess.

  • At this stage we must specify an action plan to recommend management actions for the recovery of the declining bird population. Management actions are limited. We cannot in the short term alter climate. Regulating toxic chemical use in agriculture takes years. In a few cases we can set aside more habitat as a generalized solution for all declining birds. We have difficulty controlling invasive species, and some invasive species might be native species expanding their geographic range (e.g. Bodine and Capaldi 2017, Thibault et al. 2018).

Conservation ecologists are now up against the wall because all management actions that are recommended will cost money and will face potential opposition from some people. Success is not guaranteed because most of the data available are inadequate. Medical doctors face the same problem with rare diseases and uncertain treatments when deciding how to treat patients with no certainty of success.

In my opinion the data on which the present concern over bird losses is too poor to justify the hyper-publicity about declining birds. I realize most conservation biologists will disagree but that is why I think we need to lift our game by having a more rigorous set of data rules for categories of concern in conservation. A more balanced tone of concern may be more useful in gathering public support for management efforts. Stanton et al. (2018) provide a good example for farmland birds. Overuse of the word ‘extinction’ is counterproductive in my opinion. Trying to provide better data is highly desirable so that conservation papers do not always end with the statement ‘but detailed mechanistic studies are lacking’. Pleas for declining populations ought to be balanced by recommendations for solutions to the problem. Local solutions are most useful, global solutions are critical in the long run but given current global governance are too much fairy tales.

Bodine, E.N. and Capaldi, A. (2017). Can culling Barred Owls save a declining Northern Spotted Owl population? Natural Resource Modeling 30, e12131. doi: 10.1111/nrm.12131.

Dorey, K. and Walker, T.R. (2018). Limitations of threatened species lists in Canada: A federal and provincial perspective. Biological Conservation 217, 259-268. doi: 10.1016/j.biocon.2017.11.018.

Rosenberg, K.V., et al. (2019). Decline of the North American avifauna. Science 366, 120-124. doi: 10.1126/science.aaw1313.

Stanton, R.L., Morrissey, C.A., and Clark, R.G. (2018). Analysis of trends and agricultural drivers of farmland bird declines in North America: A review. Agriculture, Ecosystems & Environment 254, 244-254. doi: 10.1016/j.agee.2017.11.028.

Thibault, M., et al. (2018). The invasive Red-vented bulbul (Pycnonotus cafer) outcompetes native birds in a tropical biodiversity hotspot. PLoS ONE 13, e0192249. doi: 10.1371/journal.pone.0192249.

http://cosewic.ca/index.php/en-ca/assessment-process/wildlife-species-assessment-process-categories-guidelines/quantitative-criteria