Category Archives: Conservation Biology

The Central Predicament of Ecological Science

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Ecology like all the hard sciences aims to find generalizations that are eternally true. Just as physicists assume that the universal law of gravitation will still be valid 10,000 years from now, so do ecologists assume that we can find laws or generalizations for populations and ecosystems that will be valid into the future. But the reality for ecological science is quite different. If the laws of ecology depend on the climate being stable, soil development being ongoing, evolution being optimized, and extinction being slow in human-generation time, we are in serious trouble.

Paleoecology is an important subdiscipline of ecology because, like human history, we need to understand the past. But the generalizations of paleoecology may be of little use to understand the future changes the Earth faces for one major reason – human disturbance of both climate and landscapes. Climates are changing due to rising greenhouse gases that have a long half-life. Land and water are being appropriated by a rising human population that is very slow to stabilize, so natural habitats are continually lost. There is little hope in the absence of an Apocalypse that these forces will alleviate during the next 200 years. Given these changes in the Anthropocene where does ecology sit and what can we do about it?

If climate is a major driver of ecological systems, as Andrewartha and Birch (1954) argued (to the scorn of the Northern Hemisphere ecologists of the time), the rules of the past will not necessarily apply to a future in which climate is changing. Plant succession, that slow and orderly process we now use to predict future communities, will change in speed and direction under the influence of climatic shifts and the introduction of new plant species, plant pests, and diseases that we have little control over. Technological optimists in agriculture and forestry assume that by genetic manipulations and proper artificial selection we can outwit climate change and solve pest problems, and we can only hope that they are successful. Understanding all these changes in slow-moving ecosystems depends on climate models that are accurate in projecting future climate changes. Success to date has been limited because of both questionable biology and poor statistical procedures in climate models (Frank 2019; Kumarathunge et al. 2019; Yates et al. 2018).

If prediction is the key to ecological understanding, as Houlahan et al. (2017) have cogently argued, we are in a quandary if the models that provide predictions wander with time to become less predictive. Yates et al. (2018) have provided an excellent review of the challenges of making good models for ecological prediction. As such their review is either encouraging – ‘here are the challenges in bold type’ – or terribly depressing – ‘where are the long-term, precise data for predictive model evaluation?’ My colleagues and I have spent 47 years trying to provide reliable data on one small part of the boreal forest ecosystem, and the models we have developed to predict changes in this ecosystem are probably still too imprecise to use for management. Additional years of observations produce some ecosystem states that have been predictable but other changes that we have never seen before over this time frame of nearly 50 years.

In contrast to the optimism of Yates et al. (2018), Houlahan et al. (2017) state that:

“Ecology, with a few exceptions, has abandoned prediction and therefore the ability to demonstrate understanding. Here we address how this has inhibited progress in ecology and explore how a renewed focus on prediction would benefit ecologists. The lack of emphasis on prediction has resulted in a discipline that tests qualitative, imprecise hypotheses with little concern for whether the results are generalizable beyond where and when the data were collected.  (page 1)

I see this difference in views as a dilemma because despite much talk, there is little money or interest in the field work that would deliver reliable data for models in order to test their accuracy in predictions at small and large scales. An example this year is the failure of the expected large salmon runs to the British Columbia fishery, with model failure partly due to the lack of monitoring in the North Pacific (https://globalnews.ca/news/5802595/bc-salmon-stocks-plunge/; https://www.citynews1130.com/2019/09/09/worst-year-for-salmon/ , and in contrast with Alaska runs: https://www.adn.com/business-economy/2019/07/25/bristol-bay-sockeye-harvest-blowing-away-forecast-once-again/ ). Whatever the cause of the failure of B.C. salmon runs in 2019, the lack of precision in models of a large commercial fishery that has been studied for at least 65 yeas is not a vote of confidence in our current ecological modelling.

Andrewartha, H.G. and Birch, L.C. (1954) ‘The Distribution and Abundance of Animals.’ University of Chicago Press: Chicago. 782 pp.

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.

Houlahan, J.E., McKinney, S.T., Anderson, T.M., and McGill, B.J. (2017). The priority of prediction in ecological understanding. Oikos 126, 1-7. doi: 10.1111/oik.03726.

Kumarathunge, D.P., Medlyn, B.E., Drake, J.E., Tjoelker, M.G., Aspinwall, M.J., et al. (2019). Acclimation and adaptation components of the temperature dependence of plant photosynthesis at the global scale. New Phytologist 222, 768-784. doi: 10.1111/nph.15668.

Yates, K.L., Bouchet, P.J., Caley, M.J., Mengersen, K., Randin, C.F., Parnell, S., Fielding, A.H., Bamford, A.J., et al. (2018). Outstanding challenges in the transferability of ecological models. Trends in Ecology & Evolution 33, 790-802. doi: 10.1016/j.tree.2018.08.001.

On Planting Trees to Solve the Climate Emergency

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Rising CO2 levels could possibly be stopped by planting lots of trees. In recent months the media have rejoiced in a proposal (The Bonn Challenge) to plant trees on 350 million ha of degraded forest land around the globe by 2030 and thereby stop or greatly slow the global increase in CO2. The Bonn Challenge was first proposed in 2011 at a meeting in Germany and to date 43 countries have made pledges to plant trees to cover about half of the proposed needs, perhaps a total of 1 billion trees. Lewis et al. (2019) recently reported on progress to date in meeting this challenge. The question that a flurry of letters to Nature and other journals have raised is whether this goal is ecologically feasible.

There has always been a cohort of scientists seeking a technological fix to the climate emergency by capturing greenhouse gases or changing the atmosphere. To date all these technological fixes fail the economic test. Can biologists ride to the rescue for the CO2 problem and save the world? Clearly many people as well as politicians are technological optimists who hope that we can continue our lifestyle with little change in the coming decades. No one likes nay-sayers but it is important to hear what problems might arise to achieve a forestry solution to the climate emergency.

Lewis et al. (2019) mapped the land areas potentially available for restoration by planting trees. To achieve the Bonn Challenge most plantings would need to be in tropical and subtropical areas where tree growth is rapid. Bond et al. (2019) concentrated their analysis on Africa where about 1 million km2 have been proposed for restoration with trees. But they point out that much of this proposed area is grassland and savannah which support high value biodiversity. Tanzania we might presume would not be happy if the Serengeti was converted to a closed forest ecosystem. If we proceed with the Bonn Challenge and grasslands and savannahs become closed forests, several unintended consequences would occur. Trees utilize more water to grow and given a fixed rainfall in an area, less water would go into rivers, streams and lakes. Trees also absorb more solar radiation so that the climate in the restored areas would warm, while a main objective of the Bonn Challenge is to reverse global warming.

The list of ecological problems is long. Plantations of monocultures typically capture less CO2 than natural forests on the same land area. Forest fires release large amounts of CO2 from both natural forests and plantations, and rising temperatures are increasing forest losses to fire. Carbon capture estimates depend critically on turnaround times which depend on tree growth rates and the uses to which wood is put after a tree is harvested. Smith et al. (2015) concluded in an earlier analysis that afforestation could not achieve the goal of limiting global warming below 2ºC.

All these problems should not stop the reforestation of closed forest areas that were degraded in historical time, as Bond et al. (2019) have pointed out. But unfortunately, this news that we cannot reverse climatic warming by planting large numbers of trees continues the negativity that bedevils the science of ecology – you cannot achieve this goal given the ecological constraints of the Earth. Politicians and the public at large do not want to hear these messages and prefer the belief that technology will come up with a simple inexpensive solution. To shout that “this will not work” is not a way to become popular.

We appear not to have progressed from what David Schindler said 22 years ago:

“Humans, including ecologists, have a peculiar fascination with attempting to correct one ecological mistake with another, rather than removing the source of the problem.”
                  (Schindler 1997, pg.4).

Bond, W.J., et al. (2019). The Trouble with Trees: Afforestation Plans for Africa. Trends in Ecology & Evolution (in press). doi: 10.1016/j.tree.2019.08.003.

Lewis, S.L., et al. (2019). Regenerate natural forests to store carbon. Nature 568, 25-28 (4 April 2019). doi: 10.1038/d41586-019-01026-8.

Schindler D.W. (1997). Liming to restore acidified lakes and streams: a typical approach to restoring damaged ecosystems? Restoration Ecology 5, 1-6. doi: 10.1046/j.1526-100X.1997.09701.x.

Smith, P. et al. (2016). Biophysical and economic limits to negative CO2 emissions. Nature Climate Change 6, 42-50 (January 2016). doi: 10.1038/nclimate2870.

Thoughts on Wildlife Management

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Stop for a moment and think about where we are now in the science of wildlife management and conservation. Look at the titles of paper in our scientific journals. The vast majority of the problems and questions being investigated are basically about how to reverse some human-caused folly. Many wildlife scientists, ecologists, and organismal biologists entered science with the goal of understanding natural systems from the ecosystem down to the molecular level but in the past 60 years the focus has had to shift. This shift has occurred almost unnoticed because it has been gradual in the time scale of human employment and turnover. The ecosystems of the world are in a frightful mess, and virtually all the mess is human caused. So while we engage in many discussions about how to define the ‘Anthropocene’ in the geological sciences (Correia et al. 2018; Zalasiewicz et al. 2017) ecological science is left in the dust because it never leads to ‘progress’.

This came home to me when I considered which of the many study sites in which classical ecological research has been carried out over the last century still exist. They have been replaced by suburbs, highways, shopping malls, farms, and industrial sites, and the associated waterways have been altered beyond recognition. A simple consequence is that if you wished to repeat a famous ecological study done 50-100 years ago, you could not do it because the site has been obliterated. One consequence is that if we wish to do field work today, we choose a new site that has so far been protected from development.

The elephant in the room now is climate change, so if you choose to investigate the trophic dynamics of an Amazonian forest area (for example), you face two problems – the site could be obliterated by ‘development’ before your work is completed, or the climate changes expected during the next 80 years will alter the trophic dynamics of your site so that your current results are no guide to the future state of these ecosystems. Whither predictive ecology? Many of us thought that by discovering and analyzing ecological principles, we could closely approach the precision of the physical sciences, the laws of physics and chemistry. But the more we search for generality in ecology the less we find. We retreat to general principles that are too vague to be of any predictive use for the wildlife managers of the future.

The thought has been prevalent that by investigating the changes in communities and ecosystems in the past we would have a guide to the future. This belief guides much of paleo-ecological research as well as the projections from evolutionary research of how species have recovered from the recent ice ages. But the past is perhaps not necessarily a good guide to the future when we add in the human footprint arising from the combination of population growth and climate change. Ecologists are left with the concern that our findings have much current value but perhaps little long-term insight. 

Many current papers on ecological changes assume a simple extrapolation predicting the future state of ecosystems (e.g. Martin et al. 2019; Yu et al. 2019). Testing these kinds of extrapolations is virtually possible within the lifetime of the typical ecologist, and my concern is that management actions that are recommended now may be completely off the mark in 30 years. Several papers have warned about this (e.g. Inkpen 2017; La Marca et al. 2019; Mouquet et al. 2015) but as far as I can determine to little effect.

I think the bottom line might be a recommendation for all predictive papers to state a strong prediction and a defined time frame so that there is hope of testing the predictive model in ecological time. Otherwise we ecologists begin to fall into the realm of science fiction.

Correia, R.A. et al. (2018). Pivotal 20th century contributions to the development of the Anthropocene concept: overview and implications. Current Science 115, 1871-1875. doi: 10.18520/cs/v115/i10/1871-1875.

Inkpen, S.A. (2017). Are humans disturbing conditions in ecology? Biology & Philosophy 32, 51-71. doi: 10.1007/s10539-016-9537-z.

La Marca, W. et al. (2019). The influence of data source and species distribution modelling method on spatial conservation priorities. Diversity & Distributions 25, 1060-1073. doi: 10.1111/ddi.12924.

Martin, D. et al. (2019). Long-distance influence of the Rhône River plume on the marine benthic ecosystem: Integrating descriptive ecology and predictive modelling. Science of The Total Environment 673, 790-809. doi: 10.1016/j.scitotenv.2019.04.010.

Mouquet, N. et al. (2015). Predictive ecology in a changing world. Journal of Applied Ecology 52, 1293-1310. doi: 10.1111/1365-2664.12482.

Yu, F., et al. (2019). Climate and land use changes will degrade the distribution of Rhododendrons in China. Science of The Total Environment 659, 515-528. doi: 10.1016/j.scitotenv.2018.12.223.

Zalasiewicz, J. et al. (2017). The Working Group on the Anthropocene: Summary of evidence and interim recommendations. Anthropocene 19, 55-60. doi: 10.1016/j.ancene.2017.09.001.

How Big an Area is Big Enough for Conservation?

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The larger the species, the more likely it is to be a species of conservation concern. Like many principles of conservation biology, this statement is a generalization with many exceptions. Often it has to be coupled with a statement of the geographic range size of the species of concern and the disturbances wrought by humans within this geographic range. And on top of these ecological issues, there are genetic concerns about population viability. The net result of all these issues is that conservation tends to focus on single species and to minimize the need to understand community and ecosystem dynamics. There is a limit on what we can achieve with limited funding and person-power. The public consensus at this time seems to be that we are losing the battle, that biodiversity is being lost on a global scale, even though we are winning the battle for some charismatic species (e.g. waterfowl, Anderson et al. 2018).

The scale issue is what has continued to defeat us. Take any group of species from your local area and try to determine what size of national park or protected area would be required for that group to survive for your great-grandchildren. No one knows the answer to this simple question, except for the negative finding that at present no protected area is large enough to prevent serious biodiversity loss of a 50-year time scale, no matter what its size.

One escape from this loss of biodiversity has been to call for establishing larger protected areas for conservation, and it leads directly into the critical question of how big a protected area is needed. This question can be analyzed at the level of the single species or an entire ecosystem, but the result is always the same – however big the protected area, it is not big enough. The only answer ecologists have to this challenge is to set up protected areas as large as is politically possible and then monitor them to see how they perform. The skeptic claims immediately that climate collapse will render the selected large protected areas unsuitable for many of the area’s fauna and flora as time progresses.

We cannot at present answer the simple question how big is big enough? The result of all this uncertainly is that we must set boundaries to our conservation goals, and that these will have to be on a local scale. We need to define a time limit for achieving our goals, perhaps 50 years is one we could cope with, and we need to monitor a defined subset of species so that we can track the resilience of the system under study over time and be able to use some feasible management tools if species are in long-term decline. Some national parks are now able to set these goals and keep track of how ecosystems are changing but in a majority of cases we do not have the monitoring data to define success or failure. This problem is not new (Newmark 1985, 1995).

Meanwhile we search for alternative approaches. In some cases, corridors between small protected areas are helpful, and in other cases fenced areas are sufficient for protecting threatened species, particularly when introduced predators are the major problem (Legge et al. 2018). More elaborate approaches must take account of climate change on protected areas (e.g. Rilov et al. 2019). Methods are being developed to deal with mosaic ecosystems in which conservation reserves are embedded in agricultural landscapes (Nowack et al. 2019). The conflict always remains whether to aim conservation at specific taxa or to try to maximize the number of species retained.

These issues of how big are most readily solvable in areas like northern Canada or Alaska, Russia, and in marine environments that are still relatively lightly used for human activities. Analyses of particular groups of taxa (e.g. trees, Médail et al. 2019) can also be usefully evaluated for conservation purposes for relatively large landscapes. The question of how big is big enough will continue to an important one for continuing efforts in conservation.

The assumption we should question is what size of area will protect the small species of insects and plants. It often seems to be assumed that our existing parks are too small for the larger species of the fauna and flora but are sufficiently large for small insects and plants. One should doubt that this simple principle is correct.

The related question of how long is long enough (for monitoring) is much simpler to deal with because in principle there should be no limit. In practice this limit is set by money and person-power, and in the end these decisions will rest on how much the world’s leaders are concerned about the loss of biodiversity. If the value of a species is directly related to its size, much could be lost with little public concern, and these questions of how big and how long will be “academic” in the worst sense of this word.

Anderson, M.G., et al. (2018) The migratory bird treaty and a century of waterfowl conservation. Journal of Wildlife Management, 82, 247-259. doi: 10.1002/jwmg.21326

Hewson, C.M., et al. (2018) Estimating national population sizes: Methodological challenges and applications illustrated in the common nightingale, a declining songbird in the UK. Journal of Applied Ecology, 55, 2008-2018. doi: 10.1111/1365-2664.13120

Legge, S., et al. (2018) Havens for threatened Australian mammals: the contributions of fenced areas and offshore islands to the protection of mammal species susceptible to introduced predators. Wildlife Research, 45, 627-644. doi: 10.1071/WR17172

Mason, C., et al. (2018) Telemetry reveals existing marine protected areas are worse than random for protecting the foraging habitat of threatened shy albatross (Thalassarche cauta). Diversity & Distributions, 24, 1744-1755. doi: 10.1111/ddi.12830

Médail, F., et al. (2019) What is a tree in the Mediterranean Basin hotspot? A critical analysis. Forest ecosystems, 6, 17. doi: 10.1186/s40663-019-0170-6

Newmark, W.D. (1985) Legal and biotic boundaries of Western North American National Parks: A problem of congruence. Biological Conservation, 33, 197-208. doi: 10.1016/0006-3207(85)90013-8

Newmark, W.D. (1995) Extinction of mammal populations in Western North American national parks. Conservation Biology, 9, 512-526. doi: 10.1046/j.1523-1739.1995.09030512.x

Nowack, S., Bauch, C.T. & Anand, M. (2019) A local optimization framework for addressing conservation conflicts in mosaic ecosystems. PLoS ONE, 14, e0217812. doi: 10.1371/journal.pone.0217812

Rilov, G., et al. (2019) Adaptive marine conservation planning in the face of climate change: What can we learn from physiological, ecological and genetic studies? Global Ecology and Conservation, 17, e00566. doi: 10.1016/j.gecco.2019.e00566

Big Science – Poor Data?

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The big global problems of our time are climate change, human population growth, and migration. From these emerge all the others that worry us from inequality leading to poverty, regional wars, emerging diseases, and biodiversity loss. As ecologists we typically worry about climate change and biodiversity loss. We can do little directly about climate change except to change our life style and replace our do-nothing-politicians. We can have some effect on biodiversity conservation, a subject of later discussions. But the elephant in the room is always climate change, and Bill McKibben (2019) has presented us with a synopsis of a positive evaluation from the viewpoint of fossil fuels and is currently bringing out a book on these issues (McKibben 2019a).

There is much discussion of these articles in reviews such as Diamond (2019) and in the social media. The negative concerns for the future have in recent years been getting more press than the positive possibilities and these negative views may cause the public to give up and say all efforts are hopeless. But these three references from McKibben and Diamond push the possibility of a positive outcome, premised partly on the growing concern of humans to the effects of climate change and the emerging technologies in energy capture that do not depend on oil and gas. I do not wish to question these statements but rather to raise the question of where ecological scientists should fit into this picture.

If natural capital is in decline and some to many species are at risk of extinction, what should be the reaction of a young ecologist just starting their ecological career? I can see two extreme responses to the current situation. One I will call the Carry-on-Regardless approach, and the other the Mad Panic approach. The Carry-on Regardless approach believes that we as one or a few scientists have little ability to change the global paradigm of environmental destruction. Certainly, we will use our own efforts to educate and give good environmental example to all we encounter. But as a scientist the most important achievement one can make is to do good ecological science, to understand in some small way how populations and communities of organisms interact and sustain themselves at the present time. In this way we can hopefully solve some immediate practical problems but more importantly collect some critical data for the next generations of ecologists to use in understanding the changes that will go on during the next several centuries. In a simple manner, future ecologists will be able to say, ‘so this is how system X was working in 2020”. We have no way to know now how much our hard-earned knowledge will be useful to our great-grandchildren, but we press on in the hope that it will be of some help in understanding the trace of the human footprint down the ages.

The Mad Panic approach at the other extreme argues that you should stop all the research that you are doing and become an advocate to try to convince the world to change course and prevent disaster. There is no time to do research, we ought to be out there shouting from the rooftops. If you wish to work at the research end of this school of thought you should perhaps be looking for an ecological disaster (e.g. plastics in the ocean) that you can investigate to beat politicians over the head about how we must change now to prevent further disaster. There is certainly a need for this sort of action.

The problem is how to advise ecologists starting their careers. There is no simple answer, and some are better at the first approach and others at the second. The key point is that we need both, and my concern (being a Carry-on phenotype) is that we need to have clear and precise data of how the planet is changing as a prerequisite for the second approach. We do not have this now except for a few species in a few locations. We have very little long-term data on biodiversity, and we only kid ourselves if we decide that a 3-year study can be classified as a long-term study, or that a list of species in a given area tells us something about ecosystem function. Consider how long it has taken to show clear trends in climate data, or in a more news-worthy area how little economic understanding has emerged from all the detailed minute-by-minute data on the stock market over the last 70 years.

So, we end up with big questions and poor data, and somehow hope that we can model the future changes in the world’s ecosystems to give the public guidance. To achieve this goal, we need more Carry-on Regardless ecologists doing good work and fewer, less strident Mad Panic environmentalists. Environmental warning bells are certainly going off, and we should listen to them and try to gather the data necessary to understand what is happening and how good management might counter negative environmental trends. It is good to be optimistic, but we must couple our optimism with strong ecological studies to understand how communities and ecosystems function. And we are a long way from having enough of these basic studies to be confident of future projections to guide the next generations.

Diamond, Jared. 2019. Striking a balance between fear and hope on climate change. New York Times, 15 April 2019.

McKibben, Bill. 2019. A Future Without Fossil Fuels? New York Review of Books, April 4, 2019, pp.

McKibben, Bill. 2019a. Falter: Has the Hunan Game Begun to Play Itself Out? Henry Holt and Company, 291 pp. ISBN:13: 9781250178268

Is Conservation Ecology Destroying Ecology?

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Ecology became a serious science some 100 years ago when the problems that it sought to understand were clear and simple: the reasons for the distribution and abundance of organisms on Earth. It subdivided fairly early into three parts, population, community, and ecosystem ecology. It was widely understood that to understand population ecology you needed to know a great deal about physiology and behaviour in relation to the environment, and to understand community ecology you had to know a great deal about population dynamics. Ecosystem ecology then moved into community ecology plus all the physical and chemical interactions with the whole environment. But the sciences are not static, and ecology in the past 60 years has come to include nearly everything from chemistry and geography to meteorological sciences, so if you tell someone you are an ‘ecologist’ now, they have only a vague idea of what you do.

The latest invader into the ecology sphere has been conservation biology so that in the last 20 years it has become a dominant driver of ecological concerns. This has brought ecology into the forefront of publicity and the resulting political areas of controversy, not necessarily bad but with some scientific consequences. ‘Bandwagons’ are for the most part good in science because it attracts good students and professors and brings public support on side. Bandwagons are detrimental when they draw too much of the available scientific funding away from critical basic research and champion scientific fads.

The question I wish to raise is whether conservation ecology has become the latest fad in the broad science of ecology and whether this has derailed important background research. Conservation science begins with the broad and desirable goal of preserving all life on Earth and thus thwarting extinctions. This is an impossible goal and the question then becomes how can we trim it down to an achievable scientific aim? We could argue that the most important goal is to describe all the species on Earth, so that we would then know what “money” we have in the “bank”. But if we look at the insects alone, we see that this is not an achievable goal in the short term. And the key to many of these issues is what we mean by “the short term”. If we are talking10 years, we may have very specific goals, if 100 years we may redesign the goal posts, and if 1000 years again our views might change.

This is a key point. As humans we design our goals in the time frames of months and a few years, not in general in geological time. Because of climate change we are now being forced to view many things in a shorter and shorter time frame. If you live in Miami, you should do something about sea level rise now. If you grow wheat in Australia, you should worry about decreasing annual rainfall. But science in general does not have a time frame. Technology does, and we need a new phone every year, but the understanding of cancer or the ecology of tropical rain forests does not have a deadline.

But conservation biology has a ticking clock called extinction. Now we can compound our concerns about climate change and conservation to capture more of the funding for biological research in order to prevent extinctions of rare and endangered species. 

Ecological science over the past 40 years has been progressing slowly through population ecology into community and ecosystem ecology while learning that the details of populations are critical to the understanding of community function and learning how communities operate is necessary for understanding ecosystem change. None of this has been linear progress but rather a halting progression with many deviations and false leads. In order to push this agenda forward more funding has clearly been needed because teams of researchers are needed to understand a community and even more people to study an ecosystem. At the same time the value of long-term studies has become evident and equipment has become more expensive.

We have now moved into the Anthropocene in which in my opinion the focus has shifted completely from trying to answer the primary problems of ecological science to the conservation of organisms. In practice this has too often resulted in research that could only be called poor population ecology. Poor in the sense of the need for immediate short-term answers for declining species populations with no proper understanding of the underlying problem. We are faced with calls for funding that are ‘crying wolf’ with inadequate data but heartfelt opinions. Recovery plans for single species or closely related groups focus on a set of unstudied opinions that may well be correct, but to test these ideas in a reliable scientific manner would take years. Triage on a large scale is practiced without discussing the issue, and money is thrown at problems based on the publicity generated. Populations of threatened species continue to decline in what can only be described as failed management. Blame is spread in all directions to developers or farmers or foresters or chemical companies. I do not think these are the signs of a good science which above all ought to work from the strength of evidence and prepare recovery plans based on empirical science.

Part of the problem I think lies in the modern need to ‘do something’, ‘do anything’ to show that you care about a particular problem. ‘We have now no time for slow-moving conventional science, we need immediate results now’. Fortunately, many ecologists are critical of these undesirable trends in our science and carry on (e.g. Amos et al. 2013). You will not likely read tweets about these people or read about them in your daily newspapers. Evidence-based science is rarely quick, and complaints like those that I give here are not new (Sutherland et al. 2004, Likens 2010, Nichols 2012).  

Amos, J.N., Balasubramaniam, S., Grootendorst, L. et al. (2013). Little evidence that condition, stress indicators, sex ratio, or homozygosity are related to landscape or habitat attributes in declining woodland birds. Journal of Avian Biology 44, 45-54. doi: 10.1111/j.1600-048X.2012.05746.x

Likens, G.E. (2010). The role of science in decision making: does evidence-based science drive environmental policy? Frontiers in Ecology and the Environment 8, e1-e9. doi: 10.1890/090132

Nichols, J.D. (2012). Evidence, models, conservation programs and limits to management. Animal Conservation 15, 331-333. doi: 10.1111/j.1469-1795.2012.00574.x

Sutherland, W.J., Pullin, A.S., Dolman, P.M., Knight, T.M. (2004). The need for evidence-based conservation. Trends in Ecology and Evolution 19, 305-308. doi: 10.1016/j.tree.2004.03.018

How to do Conservation Planning

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The biota of the Earth is in trouble because of human activities, and the question conservation people ask is what should we do about it? Conservation planning has become the key way to proceed, but its implementation has unleased an unholy row of the best way to proceed. In a sense conservation planning is like city planning in having to make decisions about what to do where. There are two broad approaches to conservation: focus on species-at-risk and their needs and plan accordingly to protect them. Alternatively focus on ecosystems and protect them without all the detailed knowledge that is required for protecting species-at-risk. This is the first source of conflict because the public at large falls in love with species, so polar bears and blue whales and tigers are an easy sell to obtain funding from private and government sources. This is at present the dominant force in conservation, and if there is enough information available the conservation of polar bears and tigers will act as “umbrella species” to protect many other species at possible risk. So single species conservation can perhaps impinge on ecosystem conservation if we designate national parks or protected areas for the charismatic species that we all admire.

But there are many other species out there that conservation biologists are concerned about, collectively labeled biodiversity. Perhaps we should conserve biodiversity instead of focusing on individual species. But right away we run into two problems. In any ecosystem many of the species present are undescribed so we cannot put a Latin name on them, or if they are described we know almost nothing about their function in the ecosystem. So, we have a key question: do we need to understand ecosystem dynamics before we can prioritize biodiversity conservation? Most ecologists believe that many of the species in any ecosystem could disappear with little effect on ecosystem functioning. The arguments are largely about which species can we dispense with, and true conservation advocates say that all must be saved.

The problem is that conservation planning is a resource allocation problem – where do we put our money (Gerber et al. 2018)? Ideas about how best to establish rules for setting aside critical areas for conservation go back to Pressey and Nicholls (1989) and in subsequent years the conservation planning literature has exploded (e.g. Margules and Pressey 2000). Techniques for conservation planning were first designed to maximize the number of species retained in the reserve, and this was the first of many problems. You had to have ‘empty’ land to set aside in the proposed reserve and you had to know the species that the reserve would protect. This was perhaps more possible in Australia or Canada but difficult to implement in the USA and Europe where much land was in private hands.

Conservation planning involves a set of difficult hurdles. If we concentrate on single species, we may well find that protected areas are in the wrong place (Mason et al. 2018). If we concentrate on ecosystems, we must decide on which ecosystems containing which species, and make this decision when the ecosystems are poorly documented and changing with climate change. All this planning must take place in the public arena where people and their elected politicians are trying to decide whether it is more important to protect large charismatic species like caribou or zebras rather than a few small butterflies. In general, all these decisions are made in a near-absence of ecological concerns about predator-prey interactions, competition, movements, or disease threats, the factors individual ecologists spend their lives studying. Much discussion focuses on critical habitat for a favoured species, and, given that we can define critical habitat for our favoured species, how much is needed and how much will it cost (Gerber et al. 2018). By 2015, critical habitat had been legally identified for only 45% of listed species in the United States, 13% in Canada and less than 1% in Australia (Martin et al. 2017, Bird and Hodges 2017). Once we have identified ‘critical habitats’ for a threatened species, we need to be sure it is not an ecological trap (Battin 2004, Camaclang et al. 2014, Lamb et al. 2017), or that the data we have is not related to the data we need for conservation planning (Dallas and Hastings 2018).

Given all these problems, many efforts are underway to plan conservation areas, particularly in the marine realm (Edgar et al. 2014, Mason et al. 2018). What is necessary now is follow up by careful monitoring the population and ecosystem changes in areas that are set aside for conservation. Without monitoring we will lack an early-warning system to pick up mistakes and try to correct them (Lindenmayer et al. 2018).  

Álvarez-Romero JG, Mills M, Adams VM, Gurney GG, Pressey RL (2018). Research advances and gaps in marine planning: towards a global database in systematic conservation planning. Biological Conservation 227, 369-382. Doi: 10.1016/j.biocon.2018.06.027

Battin J (2004). When good animals love bad habitats: ecological traps and the conservation of animal populations. Conservation Biology 18, 1482-1491. Doi: 10.1111/geb.12820

Bird SC, Hodges KE (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

Camaclang AE, Maron M, Martin TG, Possingham HP (2015). Current practices in the identification of critical habitat for threatened species. Conservation Biology 29, 482-492. Doi: 10.1111/cobi.12428

Dallas, T.A. & Hastings, A. (2018) Habitat suitability estimated by niche models is largely unrelated to species abundance. Global Ecology and Biogeography, 27, 1448-1456. Doi: 10.1111/geb.12820

Edgar GJ, et al. (2014). Global conservation outcomes depend on marine protected areas with five key features. Nature 506, 216-220. Doi: 10.1038/nature13022

Gerber LR, et al. (2018). Endangered species recovery: A resource allocation problem. Science 362, 284-286. Doi: 10.1126/science.aat8434

Lamb CT, Mowat G, McLellan BN, Nielsen SE & Boutin S. (2017) Forbidden fruit: human settlement and abundant fruit create an ecological trap for an apex omnivore. Journal of Animal Ecology, 86, 55-65. Doi: 10.1111/1365-2656.12589

Lindenmayer DB, Likens GE, Franklin JF (2018). Earth Observation Networks (EONs): Finding the Right Balance. Trends in Ecology & Evolution 33, 1-3. Doi: 10.1016/j.tree.2017.10.008

Margules CR, Pressey RL (2000). Systematic conservation planning. Nature 405, 243-253. Doi: 10.1038/35012251

Pressey RL, Nicholls AO (1989). Application of a numerical algorithm to the selection of reserves in semi-arid New South Wales. Biological Conservation 50, 263-278. Doi: 10.1016/0006-3207(89)90013-X

Martin TG, Camaclang AE, Possingham HP, Maguire LA, Chades I (2017). Timing of protection of critical habitat matters. Conservation Letters 10, 308-316. Doi: 10.1111/conl.12266

Mason C, et al. (2018). Telemetry reveals existing marine protected areas are worse than random for protecting the foraging habitat of threatened shy albatross (Thalassarche cauta). Diversity & Distributions 24, 1744-1755. Doi: 10.1111/ddi.12830

Why do Scientists Reinvent Wheels?

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We may reinvent wheels by repeating research that has already been completed and published elsewhere. In one sense there is no great harm in this, and statisticians would call it replication of the first study, and the more replication the more we are convinced that the results of the study are robust. There is a problem when the repeated study reaches different results from the first study. If this occurs, there is a need to do another study to determine if there is a general pattern in the results, or if there are different habitats with different answers to the question being investigated. But after a series of studies is done, it is time to do something else since the original question has been answered and replicated. Such repeated studies are often the subject of M.Sc. or Ph.D. theses which have a limited 1-3-year time window to reach completion. The only general warning for these kinds of replicated studies is to read all the old literature on the subject. There is a failure too often on this and reviewers often notice missing references for a repeated study. Science is an ongoing process but that does not mean that all the important work has been carried out in the last 5 years.

There is a valid time and place to repeat a study when the habitat for example has been greatly fragmented or altered by human land use or when climate change has made a strong impact on the ecosystem under study. The problem in this case is to have an adequate background of data that allows you to interpret your current data. If there is a fundamental problem with ecological studies to date it is that we have an inadequate baseline for comparison for many ecosystems. We can conclude that a particular ecosystem is losing species (due to land use change or climate) only if we know what species comprised this ecosystem in past years and how much the species composition fluctuated over time. The time frame desirable for background data may be only 5 years for some species or communities but for many communities it may be 20-40 years or more. We are too often buried in the assumption that communities and ecosystems have been in equilibrium in the past so that any fluctuations now seen are unnatural. This time frame problem bedevils calls for conservation action when data are deficient.

The Living Planet Report of 2018 has been widely quoted as stating that global wildlife populations have decreased 60% in the last 4 decades. They base their analysis on the changes in 4000 vertebrate species. There are about 70,000 vertebrate species on Earth, so this statement is based on about 6% of the vertebrates. The purpose of the Living Planet Report is to educate us about conservation issues and encourage political action. No ecologist in his or her right mind would question this 60% quotation lest they be cast out of the profession, but it is a challenge to the graduate students of today to analyze this statistic to determine how reliable it is. We all ‘know’ that elephants and rhinos are declining but they are hardly a random sample. The problem in a nutshell is that we have reliable long-term data on perhaps 0.01% or less of all vertebrate species. By long term I suggest we set a minimal limit of 10 generations. As another sobering test of these kinds of statements I suggest picking your favorite animal and reading all you can on how to census the species and then locate how many studies of this species meet the criteria of a good census. The African elephant could be a good place to start, since everyone is convinced that it has declined drastically. The information in the Technical Supplement is a good starting point for a discussion about data accuracy in a conservation class.

My advice is that ecologists should not without careful thought repeat studies that have already been carried out many times on common species . Look for gaps in the current wisdom. Many of our species of concern are indeed declining and need action but we need knowledge of what kinds of management actions are helpful and possible. Many of our species have not been studied long enough to know if they are under threat or not. It is not helpful to ‘cry wolf’ if indeed there is no wolf there. We need precision and accuracy now more than ever.

World Wildlife Fund. 2018. Living Planet Report – 2018: Aiming Higher. Grooten, M. and Almond, R.E.A.(Eds). WWF, Gland, Switzerland. ISBN: 978-2-940529-90-2.
https://wwf.panda.org/knowledge_hub/all_publications/living_planet_report_2018/

Blaming Climate Change for Ecological Changes

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The buzz word for all ecological applications for funding and for many submitted papers is climate change. Since the rate of climate change is not something ecologists can control, there are only two reasons to cite climate change as a reason to fund current ecological research. First, since change is continuous in communities and ecosystems, it would be desirable to determine how many of the observed changes might be caused by climate change. Second, it might be desirable to measure the rate of change in ecosystems, correlate these changes to some climate variable, and then use these data as a political and social tool to stimulate politicians to do something about greenhouse gas emissions. The second approach is that taken by climatologists who blame hurricanes and tornadoes on global warming. There is no experimental way to trace any particular hurricane to particular amounts of global warming, so it is easy for critics to say these are just examples of weather variation of which we have measured much over the last 150 years and paleo-ecologists have traced over tens of thousands of years using proxies from tree rings and sediment cores. If we are to use the statistical approach we need a large enough sample to argue that extreme events are becoming more frequent, and that might take 50 years by which time the argument would be made too late to request proper action.

The second approach to prediction in ecology is fraught with problems, as outlined in Berteaux et al. (2006) and Dietze (2017). The first approach has many statistical problems as well in selecting a biologically coherent model that can be tested by in a standard scientific manner. Since there are a very large number of climate variables, the possibility of spurious correlations is excessive, and the only way to avoid these kinds of results is to be predictive and to have a biological causal chain that is testable. Myers (1998) reviewed all the fishery data for predictive models of juvenile recruitment that used environmental variables as predictors and data was subsequently collected and tested with the published model. The vast majority of these aquatic models failed when retested but a few were very successful. The general problem is that model failures or successes might not be published so even this approach can be biased if only a literature survey is undertaken. The take home message from Myers (1998) was that almost none of the recruitment-environment correlations were being used in actual fishery management.

How much would this conclusion about the failure of environmental models in fishery management apply to other areas in ecology? Mouquet et al. (2014) pointed out that predictions could be classified as ‘explanatory’ or ‘anticipatory’ and that “While explanatory predictions are necessarily testable, anticipatory predictions need not be…….In summary, anticipatory predictions differ from explanatory predictions in that they do not aim at testing models and theory. They rely on the assumption that underlying hypotheses are valid while explanatory predictions are based on hypotheses to be tested. Anticipatory predictions are also not necessarily supposed to be true.” (page 1296). If we accept these distinctions, we have (I think) a major problem in that many of the predictive models put forward in the ecological literature are anticipatory, so they would be of little use to a natural resource manager who requires an explanatory model.

If we ignore this problem with anticipatory predictions, we can concentrate on explanatory predictions that are useful to managers. One major set of explanatory predictions in ecology are those associated with range changes in relation to climate change. Cahill et al. (2014) examined the conventional hypothesis that warm-edge range limits are set by biotic interactions rather than abiotic interactions. Contrary to expectations, they found in 125 studies that abiotic factors were more frequently supported as setting warm-edge range limits. Clearly a major paradigm about warm-edge range limits is of limited utility.

Explanatory predictions are not always explicit. Mauck et al. (2018) for example developed a climate model to predict reproductive success in Leach’s storm petrel on an island off New Brunswick in eastern Canada. From 56 years of hatching success they concluded that annual global mean temperature during the spring breeding season was the single most important predictor of breeding success. They considered only a few measures of temperature as predictor variables and found that a quadratic form of annual global mean temperature was the best variable to describe the changes in breeding success. The paper speculates about how global or regional mean temperature could possibly be an ecological predictor of breeding success, and no mechanisms are specified. The actual data on breeding success are not provided in the paper, even as a temporal plot. Since global temperatures were rising steadily from 1955 to 2010, any temporal trend in any population parameter that is rising would correlate with temperature records. The critical quadratic relationship in their analysis suggests that a tipping point was reached in 1988 when hatching success began to decline. Whether or not this is a biologically correct explanatory model can be determined by additional data gathered in future years. But it would be more useful to find out what the exact ecological mechanisms are.

If the ecological world is going to hell in a handbasket, and temperatures however measured are going up, we can certainly construct a plethora of models to describe the collapse of many species and the rise of others. But this is hardly progress and would appear to be anticipatory predictions of little use to advancing ecological science, as Guthery et al. (2005) pointed out long ago. Someone ought to review and evaluate the utility of AIC methods as they are currently being used in ecological and conservation science for predictions.

Berteaux, D., Humphries, M.M., Krebs, C.J., Lima, M., McAdam, A.G., Pettorelli, N., Reale, D., Saitoh, T., Tkadlec, E., Weladji, R.B., and Stenseth, N.C. (2006). Constraints to projecting the effects of climate change on mammals. Climate Research 32, 151-158. doi: 10.3354/cr032151.

Cahill, A.E., Aiello-Lammens, M.E., Fisher-Reid, M.C., Hua, X., and Karanewsky, C.J. (2014). Causes of warm-edge range limits: systematic review, proximate factors and implications for climate change. Journal of Biogeography 41, 429-442. doi: 10.1111/jbi.12231.

Dietze, M.C. (2017). Prediction in ecology: a first-principles framework. Ecological Applications 27, 2048-2060. doi: 10.1002/eap.1589.

Guthery, F.S., Brennan, L.A., Peterson, M.J., and Lusk, J.J. (2005). Information theory in wildlife science: Critique and viewpoint. Journal of Wildlife Management 69, 457-465. doi: 10.1890/04-0645.

Mauck, R.A., Dearborn, D.C., and Huntington, C.E. (2018). Annual global mean temperature explains reproductive success in a marine vertebrate from 1955 to 2010. Global Change Biology 24, 1599-1613. doi: 10.1111/gcb.13982.

Mouquet, N., Lagadeuc, Y., Devictor, V., Doyen, L., and Duputie, A. (2015). Predictive ecology in a changing world. Journal of Applied Ecology 52, 1293-1310. doi: 10.1111/1365-2664.12482.

Myers, R.A. (1998). When do environment-recruitment correlations work? Reviews in Fish Biology and Fisheries 8, 285-305. doi: 10.1023/A:1008828730759.

 

On Culling Overabundant Wildlife

2 Replies

Ecologists have written much about the culling of wildlife from an ecological and conservation perspective (Caughley 1981, Jewell et al. 1981, Bradford and Hobbs 2008, Hampton and Forsyth 2016). The recommendations for culling as a method for reducing overabundant wildlife populations are typically scientifically well established and sensitive to animal welfare. The populations chosen for culling are classified as ‘overabundant’. But overabundant is a human-defined concept, and thus requires some form of social license to agree about what species, in which conditions, should be classified as ‘overabundant’. The problem of overabundance usually arises when humans make changes that permit a species to become so numerous locally that it is having an adverse effect on its food supply, its competitors, or the integrity of the ecosystem it occupies. Once overabundance is recognized, the management issue is to determine which methods should be used to reduce abundance to a suitable level. Culling is only one option for removing wildlife, and animals may be captured and moved elsewhere if that is possible or sterilized to prevent reproduction and further increase (Liu et al. 2012, Massei and Cowan 2014).

All these policy issues are subject to open public debate and these debates are often heated because of different belief systems. Animal rights advocates may push the assumption that we humans have no rights to kill any wildlife at all. News media often concentrate on the most stringent views on controlling populations that are overabundant, and public discussion becomes impossible. Two aspects need to be noted that are often lost in any discussion. First is the cost of alternatives in dollars and cents. As an example, most ecologists would agree that wild horses are overabundant on open range in western United States (Davies et al. 2014, Rutberg et al. 2017) but the question is what to do about this. Costs to reduce horse populations by capturing horses and penning them and feeding them are astronomical (the current situation in western USA, estimated at $25,000 per animal) but this method of control could be done if society wishes to spend money to achieve this goal. Culling would be much cheaper, but the killing of large animals is anathema to many people who speak loudly to politicians. Fertility control methods are improving with time and may be more acceptable socially, but costs are high and results in population reduction can be slow in coming (Hobbs and Hinds 2018). Models are essential to sort out many of these issues, whether it be the projected costs of various options (including doing nothing), the expected population trajectory, or the consequences for other species in the ecosystem.

The bottom line is that if overabundant wildlife populations are not reduced by some means, the result must be death by starvation or disease coupled with extensive damage to other species in these ecosystems. This type of “Plan B” is the second aspect not often considered in discussions of policies on overabundant species. In the present political scene in North America opposition to culling overabundant wildlife is strong, coherent discussion is rarely possible, and Plan B problems are rarely heard. Most overabundant wildlife result from human actions in changing the vegetation, introducing new species, and reducing and fragmenting wildlife habitats. Wishing the problems will go away without doing anything is not a feasible course of action.

These kinds of problems in wildlife management are soluble in an objective manner with careful planning of research and management actions (Hone et al. 2017). Ecologists have a moral duty to present all scientific sides of the management of overabundant species, and to bring evidence into the resulting social and political discussions of management issues. It is not an easy job.

Bradford, J.B., and N.T. Hobbs. 2008. Regulating overabundant ungulate populations: An example for elk in Rocky Mountain National Park, Colorado. Journal of Environmental Management 86:520-528. doi: 10.1016/j.jenvman.2006.12.005

Caughley, G. 1981. Overpopulation. Pages 7-19 in P.A. Jewell S. Holt, and D. Hart, editors. Problems in Management of Locally Abundant Wild Mammals. Academic Press, New York. ISBN: 978-0-12-385280-9

Davies, K. W., Collins, G. & Boyd, C. S. (2014) Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe. Ecosphere, 5, 127. doi: 10.1890/ES14-00171.1

Hampton, J. O., and D. M. Forsyth. 2016. An assessment of animal welfare for the culling of peri-urban kangaroos. Wildlife Research 43:261-266. doi: 10.1071/WR16023

Hobbs, R.J. and Hinds, L.A. (2018). Could current fertility control methods be effective for landscape-scale management of populations of wild horses (Equus caballus) in Australia? Wildlife Research 45, 195-207. doi: 10.1071/WR17136.

Hone, J., Drake, V.A. & Krebs, C.J. (2017) The effort–outcomes relationship in applied ecology: Evaluation and implications BioScience, 67, 845-852. doi: 10.1093/biosci/bix091

Jewell, P. A., Holt, S. & Hart, D. (1982) Problems in Management of Locally Abundant Wild Mammals. Academic Press, New York. 360 pp. ISBN: 978-0-12-385280-9

Liu, M., Qu, J., Yang, M., Wang, Z., Wang, Y., Zhang, Y. & Zhang, Z. (2012) Effects of quinestrol and levonorgestrel on populations of plateau pikas, Ochotona curzoniae, in the Qinghai-Tibetan Plateau. Pest Management Science, 68, 592-601. doi: 10.1002/ps.2302

Massei, G. & Cowan, D. (2014) Fertility control to mitigate human–wildlife conflicts: a review. Wildlife Research, 41, 1-21. doi: 10.1071/WR13141

Rutberg, A., Grams, K., Turner, J.W. & Hopkins, H. (2017) Contraceptive efficacy of priming and boosting doses of controlled-release PZP in wild horses. Wildlife Research, 44, 174-181. doi: 10.1071/WR16123