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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
The erosion of biodiversity is currently highly publicized. Militant movements accuse humans of destroying nature and being responsible for a sixth mass extinction. However, this anxiety-provoking message is sometimes based on misconceptions, false or partisan ideas, and media relays that favor and amplify alarmist information. If the situation of certain populations is worrying, it is not a general phenomenon because others are expanding. Rather than holding a globalizing discourse, it is necessary to recontextualize and relativize the debate to better define the necessary actions. Biodiversity Erosion analyzes numerous scientific publications, as well as alarming discussions, emphasizing the multiple biases present in the way information is presented. This book questions the relevance of the notion of species and the desire to compile an inventory of all living things. It argues for a less Manichean approach to our relationship with nature.
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Seitenzahl: 474
Veröffentlichungsjahr: 2022
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Table of Contents
Cover
Title Page
Copyright
Introduction
1 The Gradual Decline of Biodiversity: What Do We Mean?
1.1. The context of the debate
1.2. “Biodiversity”? A vague concept
1.3. The origins of a concept: creationist thinking
1.4. Decline: clarifying the meaning of the words
1.5. Are the indicators reliable?
1.6. Protecting what?
1.7. The evolution of the concept of decline: from a structural to a functional approach
1.8. Communication or misinformation?
1.9. At the roots of the sixth extinction
2 The Promethean Dream: Taking Stock of Biodiversity
2.1. The notion of species is misleading!
2.2. Hidden biodiversity: cryptic or twin species
2.3. Species at the service of genes?
2.4. Species inventory: what do we know?
2.5. The geographical distribution of biological diversity
2.6. In summary
3 What Can We Learn from the Great Extinctions of the Past?
3.1. A hundred times over, put your work back together
3.2. The great mass extinctions
3.3. The tree that hides the forest
3.4. Evolutionary consequences of extinctions
3.5. What is known about the post-extinction processes of the past?
3.6. In summary
4 Biodiversity Decline: “The Worst Is Not Certain”
4.1. When scientists cross the yellow line!
4.2. The risk of extinction
4.3. Vulnerability of species to risks
4.4. Species extinctions in the plant world
4.5. What do we know about species extinctions in animals?
4.6. Species extinctions in France
4.7. The false trails of globalization: contextualizing erosion!
4.8. In summary
5 Let’s Talk about the Renewal Rate of Biological Diversity
5.1. Extinction debt and speciation credit
5.2. Speciation processes
5.3. The speed of appearance of new species
5.4. Is speciation more important in tropical environments?
5.5. Evolution and the role of chance
5.6. Is habitat fragmentation a threat to biodiversity?
5.7. In summary
6 Controversies Surrounding the Extinction Rate
6.1. The laborious calculation of the extinction rate
6.2. The area/species relationship: a highly criticized prospective tool!
6.3. Text commentary on the extinction rate of species according to the Sagascience website
6.4. A debate confused by ideological concerns
6.5. In summary
7 The Hidden Face of Methods for Assessing Biodiversity Decline
7.1. Who can be trusted to analyze the data?
7.2. Questions about the “species” metric
7.3. Amalgamation and false leads
7.4. Contingency and the problem of changes in scale: global versus local
7.5. Losers, but also winners?
7.6. Manipulating figures: communication or hijacking?
7.7. The health sector taken hostage
8 Biodiversity and the Functioning of Ecosystems: A Multitude of Preconceived Ideas
8.1. The black box of ecological functioning
8.2. The balance of nature is fiction
8.3. Disruption does not mean disaster
8.4. Are all species needed?
8.5. Deterministic or stochastic ecological systems?
8.6. The more species there are, the more resilient the ecological system is
8.7. The threshold effect or the fall of a paradigm!
8.8. Species substitutions and the functioning of ecological systems
8.9. In summary
9 Species Introductions: For Better or For Worse
9.1. The delicate issue of indigenousness
9.2. Species introductions: one of the main causes of biodiversity loss?
9.3. Species introductions and ecosystem functioning
9.4. Why are our trees sick?
9.5. Can introductions be controlled?
9.6. Being pragmatic?
9.7. Strongly divergent opinions among scientists
9.8. In summary
10 Global Warming: A Catastrophe for Biodiversity?
10.1. Climate uncertainties
10.2. The lessons of retrospective ecology
10.3. Likely consequences of reduced precipitation
10.4. Likely impacts of temperature increase on biodiversity
10.5. Rising sea levels
10.6. Undergoing or going along with change?
10.7. In summary
11 Is Planning Destroying Biodiversity?
11.1. European nature: a reconstructed nature
11.2. “Degraded” ecological systems… really?
11.3. When you transform, you lose and you win…
11.4. Paradox: destroying biodiversity under the pretext of naturalness
11.5. A brief saga of French forests
11.6. In summary
12 The Decline of Insects
12.1. The decline of insect populations creates the event
12.2. Is the apocalypse coming?
12.3. The difficulty of identifying the causes
12.4. Speculation on possible causes
12.5. What is the impact on agriculture?
12.6. The case of bees
12.7. The case of butterflies
12.8. Some remarks on our relationship with insects
12.9. In summary
13 The Decline of Birds
13.1. The red list of threatened species
13.2. The decline of bird populations… as early as the 19th century
13.3. Monitoring of the STOC program
13.4. Focus on the farmland bird guild
13.5. The habitat trail
13.6. Many other causes
13.7. The role of reserves
13.8. On what basis can we talk about decline?
13.9. Let nature take its course?
13.10. In summary
14 Reasons to be Positive
14.1. Highly resilient ecological systems
14.2. Recovering populations!
14.3. Nature conquers the city
14.4. Rehabilitation of “degraded” systems
14.5. What is the future for anthropized nature, left to its own devices?
14.6. Let’s talk about the wolf
14.7. In summary
15 From Facts to Extrapolations
15.1. Many inconsistencies and post-truths
15.2. Going beyond ecocentrism: what kinds of nature do we want?
15.3. Protected areas and the return of colonialism?
15.4. Nature, an inexhaustible source of problems
15.5. Single-mindedness and anxiety-provoking communication
15.6. The business of biodiversity
References
Index
Wiley End User License Agreement
List of Tables
Chapter 3
Table 3.1. The “five great crises” of fossil eras (adapted from Barnosky et al. ...
Chapter 4
Table 4.1. Number of endemic plant species in some European countries
Chapter 13
Table 13.1. Changes in farmland bird populations monitored by the STOC network s...
Table 13.2. Status of some familiar insectivorous species, according to the Vigi...
List of Illustrations
Chapter 3
Figure 3.1. Extinction rate (%) of multicellular marine invertebrates over fossi...
Figure 3.2. Evolution of marine biodiversity expressed in thousands of genera du...
Chapter 4
Figure 4.1. Proportion of terrestrial and freshwater endemic and sub-endemic spe...
Chapter 6
Figure 6.1. Species richness and watershed area. For the same catchment area, Af...
Chapter 9
Figure 9.1. The palm moth (Paysandisia archon), originating from South America, ...
Chapter 10
Figure 10.1. Adapted from the IPCC synthesis report (2001) and Mégie and Jouzel ...
Figure 10.2. Annual soil drought indicator in France published on the ClimatHD w...
Chapter 11
Figure 11.1. The Der-Chantecoq artificial reservoir lake has become an exception...
Figure 11.2. The sacred ibis. Originally from Africa, where it is endangered, th...
Chapter 12
Figure 12.1. Comparison of raw data and modeling of insect biodiversity loss acc...
Figure 12.2. Changes in the butterfly indicator from 1990 to 2015, calculated by...
Chapter 13
Figure 13.1. Changes in the abundance indicator for some bird guilds monitored u...
Figure 13.2A. Evolution of the index of abundance of common bird populations acc...
Figure 13.2B. Evolution of the index of abundance of common bird populations acc...
Figure 13.3. Decline of farmland birds in four European regions. Data: indicator...
Guide
Cover
Table of Contents
Title Page
Copyright
Introduction
1 The Gradual Decline of Biodiversity: What Do We Mean?
References
Index
Wiley End User License Agreement
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Biodiversity Erosion
Issues and Questions
Christian Lévêque
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
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© ISTE Ltd 2022
The rights of Christian Lévêque to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.
Library of Congress Control Number: 2022934060
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ISBN 978-1-78630-762-0
Introduction
Environmentalists need to take a serious look at themselves and their priorities. Nature is no longer found only where we expect to find it, in the countryside or in “pristine” habitats. It increasingly avoids officially protected areas and heads for the ungrateful lands. Nature does not care about the artificial division between urban and rural areas, or between native and alien species. If ecologists are to make the most of the opportunities of the 21st century to help restore nature, they must put aside their old certainties and abandon their obsessions with lost causes, discredited theories and mythical pristine ecosystems.
(Pearce 2015)
The erosion of biodiversity is part of the more general context of the relationships that the human species has with other species. Our ways of living on Earth obviously have an impact on biological diversity… how could they not? Like other species, we depend on the resources we obtain from nature, and it is hard to imagine doing without them. Our presence on Earth is not without consequences for other species so the myth of having nature unaffected, which some activist movements aspire to, is simply incompatible with the presence of humans. There is no neutral situation because nature is not a kind of la-la land. It is a brutal and cruel world where the priority is to survive, by any means possible, and to protect oneself as best as possible from predators. This is how the human species began its long adventure. And it is still in this context that there are billions of living human beings who do not know the comfort of life that progress has given us in the West. This comfort has been acquired by securing our food sources through agriculture and by securing our living environment through controlling disease vectors and various harmful substances that nature has in abundance. As Sylvie Brunel says:
It is man’s way of inhabiting the Earth that has made it pleasant to live on… the whole history of man’s presence on Earth is one of a permanent struggle to survive, despite the unleashing of blind and sudden forces (Brunel 2011).
We are not in a Garden of Eden where wolves and sheep live side by side, but in a world where people have to fight to survive. And in a world where the human population is expanding rapidly, there is necessarily an impact on non-humans. In other words, there is inevitable collateral damage. What is up for discussion, though, is the possibility of minimizing this damage, as opposed to believing in the myth that nature can be preserved in its entirety. Yet the reported increase in protected area policy, which consists of excluding humans in order to protect nature, is totally ecocentric. In addition to the ideological, and even mystical, approach that presides over this policy, it is so far removed from the experience of the vast majority of human beings that it can only lead to conflict and failure.
This point of view, of course, is not in line with the current high-profile discourse on biodiversity, as conveyed by nature conservation NGOs and certain activists who systematically accuse humans of destroying nature. Their deliberately anxiety-provoking statements, announcing a sixth mass extinction, is caricatural and excessive. It is caricatural in its bias to speak only of the degradation and destruction of nature and to suggest that we should increase the protected areas… that excludes humans. And it is excessive due to the outrageousness of the comments made about the current situation and the manipulation of information for militant purposes. The numerous “scientific” predictions, which have been proven inaccurate, end up discrediting their authors as well as the ecological science they hide behind. These statements pave the way for collapsologists who predict the end of humanity. This was done in the Middle Ages by arousing the fear of hell. If we want to make progress in reflecting on our relationship with nature and seriously tackle the problem of the erosion of biodiversity, we must play the game without stealing the cards. As we will see, the use of systematically alarmist speeches and the hijacking of scientific results do not help.
I refuse to join this new religion, which aims to sanctify nature and demonize the role of humankind, which is asked to step aside to protect it. When I saw the forest of Borneo being burned, I thought, like many others, of the sad future that was reserved for our cousin, the orangutan. However, when I walk through the wooded countryside of my native country, which is a beautiful example of nature managed by humans, just like the Camargue and many other nature hotspots in France, I find it hard to see the destructive hand of humans. Yet I must admit that hedges have disappeared, and I can no longer find the ponds in which I experienced my first emotions as a naturalist while collecting salamanders and diving beetles. In other words, there are contrasting situations. While there is no doubt that certain changes in our landscapes are to be deplored, not everything is bleak in the relationship we have with this European nature that our ancestors have helped to build over the centuries, and that we are seeking to perpetuate. Far from the dogma of nature degraded by humans, it is heritage nature that we are dealing with. But, as with many human endeavors, we can look at the current developments in both positive and negative ways. The creation of a reservoir dam on the Marne (the Lake Der-Chantecoq) to protect Paris against flooding is a scandal for militant movements hostile to development. Yet this same dam, which was created at the expense of wooded countryside, has become an extraordinary ornithological spot that welcomes North European migratory birds. It has also been labeled a Ramsar site, recognizing its international importance. How, in such a context, can we adhere to anxiety-provoking speeches, when many examples show us that it would be wiser to have a less dogmatic approach to our relationship with nature?
I would add, since my career has led me to work in programs to combat major endemic diseases, that environmentalist discourse pays little attention to the many nuisances that nature also causes. The fight against diseases and their vectors, as well as the fight against crop pests, which require a great deal of effort, are totally marginalized in speeches that speak of a good and generous nature that we are supposed to live in harmony with! Although the number of undesirable insect species is relatively low (Chapter 12), their impact on our health and economy is considerable. Biodiversity protection will remain flawed as long as it is based exclusively on the dogma of nature as beautiful and good, harmed by humans, without also taking into account these two aspects of our relationship with nature.
It is probably very naive of a scientist to think that only results based on validated observations should be used for debate. In reality, many random speculations, or received ideas, are presented as indisputable truths to feed the doxa of gradual destruction. “Science has said” is an argument of authority sometimes used by those who seek to impose their point of view in order to avoid debate. However, when we take the trouble to read the published works, the often-cautious scientific results are often misrepresented and used by activists to fuel partisan discourse. Not to mention the fact that scientists are divided on these issues and that the media, for commercial reasons, give priority to alarmist speeches that sell.
What is more worrying, in my opinion, is that part of environmental science that should have remained neutral and approached the question of human–nature relations without any negative preconceived ideas has in reality turned massively towards research that is essentially intended to support the dogma of humans as the destroyer of nature, without considering that this might not be the case and that this runs contrary to development, to introduced species, to pest control, to our economic systems, etc. We search the literature in vain for works dealing with the “positive” relationships we have established with nature and which are favorable to biodiversity, as we depict it. This is not to take the systematic opposite view of the conservationist discourse, but to weigh it up and suggest that there are other alternatives. Thus, to put it in a positive light, many of our sites that are designated as sites for the protection of biodiversity are artificial systems, like the emblematic example of the Camargue. How can the nature in which we live in Europe, one which has been gardened for centuries and is far from being a biological wilderness, be any less valuable than a hypothetical nature free of humans and their effects, as demanded by militant movements (Blandin 2009)? Unless, of course, as is sometimes the case, we are still permeated with the theological conception of a perfect nature created by God and destroyed by humans.
However, the recurring conclusions of major international meetings and numerous reports on the issue are convergent: we are not succeeding in halting the gradual decline of biodiversity. If it continues, despite the measures that have been taken, which are not anecdotal, it is likely that this is because the efforts made are coming up against strong constraints that are difficult to overcome, as Orr (2003) has already pointed out. In this case, it is necessary to take note of this and consider how to deal with these constraints. But it is also possible to think that the very concepts of conservation, as developed by the conservationist movements, are inappropriate and that alternatives must be considered. In either case, this requires a rethink. Instead, though, we tend to rush ahead with a policy of protected areas which has shown its limits. The indicator has just been set at 30% of the territories under protection by 2030, but activists are already saying that this is merely a step in the right direction and are starting to talk about 50%. However, by multiplying protected areas, we are also depriving indigenous populations of the resources they need, in a context where the world’s population is growing. Neo-colonialism is omnipresent in the policies of the NGOs that dreamed, in 1992 in Rio, of being given the role of a nature protection watchdog. In fact, with these ecocentric policies, there is little interest in the fate of human beings, who will in turn be confined to indigenous reservations, thus increasing their impoverishment and the degradation of nature in the areas granted to them (Blanc 2020).
This creates a smokescreen to avoid saying that we are not powerful enough to address the recurring issue of population growth which is at the root of most of the problems we face. We are also powerless to deal with the issue of global poverty and the deplorable living conditions of a large part of the population, which also actively contributes to our impact on nature. The distressing spectacle of the implementation of the Paris agreements does not fail to challenge us on the limits of our ambitions. We hide behind slogans such as sustainable development, which do not provide a solution… but clear our conscience! With arrogance, as they have done with religion and culture, affluent Westerners want to impose their theological vision of nature on populations that have other needs and expectations (this is the whole question of ecological interference). In short, the biodiversity business, which feeds networks, consultancy firms, “experts”, the media, scientists, etc., suits many people and it is a good thing that it does. The protection of biodiversity has become the prerogative of multi-national tentacles that have nothing to envy about the economic lobbies they denounce. International nature protection NGOs are not made up of volunteers! They have to make the business work and therefore make money, which they do not fail to do on the basis of shocking figures… which play on people’s emotions. The “catastrophic” gradual decline of biodiversity has become a sales argument with its own language and advertising system, globalization, by-products and so on. It has also become an obligatory permit when it comes to obtaining funding for research programs.
Biodiversity has thus left the orbit of the natural sciences to gravitate towards the media and politics and has become a social issue between social groups seeking to impose their world view on one another. The one-upmanship of alarmist speeches is in full swing and the collapsologists are running amok. It is no longer a question of informing but of imposing our point of view. For in today’s disoriented world, the conservationist doxa has conquered the media and the political world. For decades, scientists and politicians alike have been tirelessly churning out a list of grievances and making recommendations that are either inapplicable or unapplied. This is an intellectual cul-de-sac in which it seems that everyone can find their niche.
This book does not claim to address all these issues, but it was necessary to give an overview of the debate on biodiversity decline and relativize it in this general context by showing the discrepancy between the determination to draw up a list of accusations against humans and the difficulty of providing adequate answers in the philosophical context that currently drives conservation policies. I felt it was necessary to make it more well known, without using it for partisan purposes, that there are other points of view on our relationship with nature than those of the NGOs disseminated by the media. To let those who are informed on social networks know that scientific results do not tally with the anxiety-provoking speeches going around, and that there is a debate within the scientific community on the issue of biodiversity decline – not on the phenomenon itself, but on its magnitude and the responses to it. For this, we must go back to the published works and the often-nuanced conclusions of the authors because of the complexity of the issues raised. It is difficult to say: we do not know… and yet how many studies suggest that the conclusions should be taken with a pinch of salt, given the insufficiency of the data? Indeed, for an issue that has become so high-profile, the resources available for collecting field data are notoriously inadequate. Many authors, in various forms, are now questioning the Manicheism of militant discourse that tends to put humans and nature at odds with one another. They take a lucid look at the state of the planet without falling into a blissful optimism about our relationship with nature. To varying degrees, they denounce the sway of beliefs, the marginalization of science, anxious communication, the refusal of progress, etc. They challenge the one-track thinking imposed on us by ecologists. Read, for example, Blandin (2009), Brunel (2011), Lévêque (2013, 2017a, 2017b), Tassin (2014), Pearce (2015), de Kervasdoué (2016, 2020), Lesaffre (2018), Brunel (2019), Pavé (2019), Larrère and Larrère (2020), Oury (2020), Shellenberger (2020), and so on.
“It is around their relationships to environments and resources that different inhabitants build their social relationships on a territory,” wrote Papy and Mathieu (2008). Nicole Mathieu (2016), for her part, invites us to “rethink nature in the relationship to reality of each individual and each social group, freed from the social representations constructed in another time that encyst our analyses”. Let us admit that this is not quite the same thing as creating an apartheid between humans and nature, placing both in different reserves. This is the central issue.
1The Gradual Decline of Biodiversity: What Do We Mean?
We have gone from a nature that made us to a nature made by us.
(Moscovici 1972)
The term biodiversity was originally coined by scientists to draw attention to the destruction of tropical forests. Since then, biodiversity has become the banner that various social groups that are concerned about the future of the planet rally behind. Like climate change, it is now in the news. Like climate change, it is now making headlines in the media, against the backdrop of catastrophic and anxiety-provoking discourse. Although the consequences of human activities on biological diversity require our full attention, the fact remains that the general tone of the debates is based on an ideological bias: humans are destroying nature, which must therefore be protected by keeping it safe… from humans. The media only talks about the degradation of ecosystems while promising us the apocalypse and, for good measure, the end of humanity. And yet… are European citizens so profoundly out of touch as to forget that we have been living in a natural environment that has been managed for centuries, a gardened environment that we are paradoxically trying to protect? Patrick Blandin (2009) asks this question: in what way would this nature be less valuable than a hypothetical nature free of humans and their artifices? Wooded countryside, which is a landscape resulting from agricultural practices, is an ecological heritage system which is emblematic of this European nature. Historically, however, it is a “damaged” forest system.
Let us get one thing straight: it is not a question of saying that human activities have no impact on the living world! Only in the Garden of Eden do carnivores live in harmony with herbivores, because the “wild” is first and foremost a cruel and brutal world in which predators are constantly seeking to kill and destroy. The concept of the food web in ecology is therefore simply a formalization of this great feast of nature, in which humans take their place in competition with, and to the detriment of, other species:
The food chain is ruthless and does not have a conscience. The strong eat the weak… It takes human ethics to desire to make the garden of the Earth more beautiful, the territories more liveable, to love the animals, and to wish that they continue to exist (Brunel 2019).
While it is legitimate to be concerned about the extent and consequences of our hold on nature for ethical, moral or emotional reasons, humans’ presence cannot be neutral, and human population growth only increases the pressure. The question is not only how to deal with nature but also how to deal with it in a sustainable way. The question that arises is not to protect nature from humans, but to know how to manage our relationships with non-humans, including – when necessary – through localized protection measures. It should be noted that, in nature, as far as we know, predators do not show much empathy for their prey and other species. The preoccupation with the fate of other living organisms is therefore unique to the human species.
1.1. The context of the debate
Biological diversity or species diversity has fascinated naturalists since Antiquity, but in fact very few have been interested in it for a long time. Until the 19th century, nature was considered to be the work of God and as such was admired by men for its harmony and splendor. Questioning the dogma of Creation, transformist theories and then the theory of evolution, as well as the numerous discoveries made by traveling naturalists in the 18th century, gave rise to the emergence of the natural sciences in the 19th century, and then to ecology at the beginning of the 20th century, which set itself the goal of discovering the laws of nature that help to maintain its equilibrium over time. For the fixist conception of nature, inherited from creationist thinking remained alive for a long time. At the same time, another debate was taking place among a group of scientists seeking to show the interest their research held for society. The aim was to respond to the concerns of farmers faced with the destruction of their crops by diseases and pests. They helped to distinguish (with difficulty) between species that were useful and those that were harmful to agriculture and to find ways of controlling these phenomena. One of the steps taken was to implement protective measures for insectivorous birds, which were elevated to the rank of “farmers’ helpers” and were subject to intensive hunting when their predatory capacities were relied upon to limit the outbreak of crop pests (an early form of biological control). These protection measures, for utilitarian purposes, were also the first manifestations of an interest in “useful” biological diversity, which would be formalized much later under the name of “ecosystem services”. Later, in the 20th century, protection measures were extended to all bird species, but this time for ethical reasons.
The Romantic movement in the 19th century helped to promote the paradisiacal image of nature that is currently being promoted by conservationist NGOs and activist movements. This is a vision that seeks to impose itself on the world because of the proselytism of activists, while many citizens have a very different experience of nature. For example, farmers are still confronted with the nuisances of nature as they were in the 19th century, and, in many countries that are not fortunate enough to have achieved our Western standard of living, humans are exposed to the vectors of deadly or crippling diseases, as well as to the issue of providing food in countries with soaring populations, which leads to the overexploitation of natural resources. It is easy to understand that their relationship to nature and its protection is somewhat different from that of conservationist NGOs. This issue has been well developed in Guillaume Blanc’s book on green colonialism (Blanc 2020).
Thus, and in a schematic way, of course, we can see that there are two very different worlds in terms of representations and expectations regarding biodiversity management. For some, all species have an intrinsic value and a right to life. We should therefore protect them by reserving areas for them in which humans will be excluded. But now what about those humans? For others, nature has two faces, and the survival of humans depends primarily on the control of pests and pollutants, which obviously leads to “collateral damage”. But can we do better? In reality, there are many intermediaries between these two extremes, but we will always find this tension between the imagined paradisiacal nature and the conflicting lived nature when we talk about the gradual decline of biodiversity. Nowadays, environmental policies are strongly inspired by the discourses of NGOs and the protection of nature tends to conceal the problems that nature causes. This raises serious questions about the ideology behind these measures. In fact, the world of nature protection and those who are concerned with limiting such problems are worlds that are either in conflict with each other or, at best, ignore each other.
1.2. “Biodiversity”? A vague concept
We constantly hear about protecting biodiversity, an expression that has become an argument of authority, used left and right and indiscriminately, and for many remains an abstract entity. Strictly speaking, biodiversity is the set of species, genes and habitats that are present in a given place, region and time across the whole world, from micro-organisms to vertebrates. In other words, it is the entire biosphere. In fact, when we talk about protecting biodiversity, we are addressing only a few groups of species in which, for various reasons, we have a particular interest. There is an implicit hierarchy, and vertebrates, for example, receive much more attention than invertebrates. For instance, I have never heard of the need to protect the tapeworm, whose populations are in sharp decline. Among vertebrates themselves, there are also hierarchies in empathy. Rats and snakes are rated less highly than birds and large mammals. In practice, the focus is on groups that are arbitrarily declared to be representative of biodiversity. This is a misuse of the term that suggests that there is a universal entity (biodiversity), when in fact each group of organisms has its own dynamics and history, in very diverse ecological systems. In fact, we should talk about the biological diversity of birds or fish… which have been recorded!
In this regard, I would like to recall a saying that highlights the paradoxes of conservation: “protect a tree, eat a beaver”. Clearly, when you protect one species, it is at the expense of other species. Protecting waterbirds (cormorants, herons, etc.) leads to an increase in their numbers, which has major consequences for the fish and amphibian populations on which they feed and whose populations may collapse. Thus, talking about protecting biodiversity is not very meaningful if we do not specify what it is. Indeed, the gradual decline of certain populations may be the result of a certain species being protected.
The choice of “target” groups that are presented as “emblematic” in restoration projects can lead to questionable interpretations of biodiversity dynamics. Indeed, Magurran et al. (2018) observed, in a tropical river, that the different taxonomic components of biodiversity (fish, invertebrates and diatoms) do not show the same temporal trends. This raises a general observation: no taxonomic group can claim to represent biodiversity. It only represents itself. In France, the policy of restoring ecological continuity is based on a few species of migratory fish, which leads to the destruction of weirs and the river annexes they have created (Bravard and Lévêque 2020). But in the name of protecting biodiversity, who cares about protecting the amphibians that used to live in these stagnant water environments? They do not mix well with fish, and some species are even threatened; this is just one example of bias in biodiversity protection policies.
1.3. The origins of a concept: creationist thinking
It was with a view to taking stock of the Creator’s work that the Swedish scientist Carl Linnaeus, in the 18th century, undertook to name, classify and inventory different species. He had a fixist conception of the world, unchanging and harmonious, as it had been created by God. Many of our contemporaries still share this view because creationist thinking is still alive and well in certain religious circles. It is particularly present in North America, where a large part of the population still believes in the creation myth and there are creationist museums (Axelrod 2017)! If we adhere to this belief, then obviously the notion of species is in some way sanctified and evades any scientific definition, and the disappearance of any species becomes an attack on the work of the creator!
We may think that all this is anecdotal, and that science has taken precedence over magical thinking. But we must also face the fact that scientists involved in conservationist movements clearly display their belief in the creation of the world, as I mention in Chapter 6. In other words, we are entitled to ask the question: to what extent has creationist thinking, which is still widely prevalent in North American culture, influenced the debate on the gradual decline of biodiversity? It should also be remembered that the major environmental NGOs, which stigmatize the role of humans, are often of English-speaking origin.
In the 19th century, following Linnaeus, and under the impetus of traveling naturalists and the interest aroused by the debates on transformism and the origin of species, a few natural history enthusiasts continued and intensified the inventory of the living world and asked themselves about the laws governing its functioning. At the same time, thanks to the work of paleontologists, it became clear that species are not eternal. Cuvier and Lamarck then proposed two different hypotheses: for Cuvier, species disappear during major catastrophes. For Lamarck, species change under the influence of the environment. Although presented as competing, these two hypotheses are, in fact, complementary, as we will see later. Darwin and Wallace provided the beginnings of an explanation for the mechanisms at play in the transformation of species, without calling into question the belief in a stable world, and without providing any explanation for the origin of life other than Creation.
It is important to stress that popular culture is still pervaded by the fixist vision of a nature in equilibrium with a stable number of species (Maris 2010). The aim of ecology that emerged at the beginning of the 20th century was to research the laws that governed nature’s functioning, and, in particular, the regulatory mechanisms that allowed it to remain identical to itself! This famous “balance of nature”, which was the highlight of the nascent ecology movement, was nevertheless at odds with the evolutionary ideas of adaptation to environmental change promoted by Darwinism. It is true that the discourse on evolution focused on the characteristics of the species, whereas ecology was more interested in the dynamics of populations (communities, biota, etc.). For a long time, ecology developed theories and concepts around the notions of order and homeostasis of nature, dynamic equilibrium and resilience. All these terms conceal a permanent quest for balance. One of the avatars would be the so-called mechanistic conception of the functioning of ecosystems in the middle of the 20th century (Lévêque 2013).
Box 1.1.The dialectical relationship between humans and nature
“It is striking to note that the conception of the dialectical relationship between man and nature still pervades strongly in the Western world… by the Judeo-Christian and more generally Semitic religious heritage. In a Manichean way, man is opposed to nature. On the one hand, there is nature, whose current vision derives from the myth of the Garden of Eden, where everything is beautiful, good, fragile and in harmony. On the other, there is man, whose actions are perceived as generating imbalance, destruction and negativity (the ‘degradation’ of the environment). To ‘preserve’ and ‘protect’ nature, there is no other solution than to exclude man and create ‘reserves’. Adam (and Eve) disturbing the ‘natural’ order must be driven out of Eden” (Rossi and André 2006).
It is against this backdrop of a static representation of nature inherited from creationism that the doxa of biodiversity decline has developed with its main metric of the number of species that have become extinct due to human activity. Scientific ecology, strongly influenced by this theological premise, has essentially carried out research on humans’ actions. These are the famous impact studies (obviously the negative impact) that have flourished over the past few decades, all based on the same cartoonish principle: our activities modify ecological systems, which poses a danger (which is usually unexplained) to our survival.
It is symptomatic to underline that the charges thus brought against humans leaves no alternative but conflict in the relationship between humans and nature. The idea that humans can contribute to the enrichment of biodiversity even borders on heresy. This is why I, along with others, consider that we are in a system of ideologically biased beliefs (Bronner 2013) and not in a true reflection on human/nature relationships which, alone, would make it possible to envisage compromises between the need to meet our vital needs while maintaining, as far as possible, better relationships with non-humans.
1.4. Decline: clarifying the meaning of the words
The term “decline” signifies wear and tear, or degradation. To speak of biodiversity decline therefore implies that we refer to a previous state, a reference state that we can describe and characterize so that we can draw comparisons with the existing situation and come to conclusions. But what is this reference in terms of biodiversity? Does the notion of reference itself make sense for dynamic ecological systems that have been repeatedly reshaped by the climate and, more recently, by humans? This is understandable if we subscribe to the static vision of a harmonious and unchanging nature, inherited from creationist thinking, which, as we will see, tends to be shared by activists and several scientists (Rossi 2010; Baudouin and Brosseau 2013; Lévêque 2013; Lecointre 2018). It is difficult to imagine that we can simultaneously claim to be proponents of the Darwinian theory of evolution, which tells us that biological diversity is the product of change and adaptation, and simultaneously seek to set norms that implicitly suppose that there is a standard state.
The frequent use of the term “degradation” to describe the changes made to ecological systems is a value judgment that also refers to the image that we may have of a “normal” state, for which we vainly seek a definition, except to say that it is the state that existed before humans intervened. But then where to put the indicator when we know that, in the long term, ecological systems have not stopped transforming themselves, long before humans existed! Can we talk about “degradation” when we talk about the numerous extinctions of species that have followed glacial episodes that have affected European ecological systems on various occasions? Or should we think of this as a hazard that is part of the course of life? This shows that the way we look at certain events is not neutral, but is marked by cultural biases that have, in a way, permeated scientific thinking.
If words have a meaning, the way they are used can sometimes lead to confusion. Thus, the extinction of a species has a precise meaning: the definitive elimination of a species from the face of the Earth. But this term is often used ambiguously when we speak of the extinction (without precision) or disappearance of a species that are no longer encountered in a given place while they are still present in other places. This is a local and sometimes temporary phenomenon. In addition, we know that, with global warming, species’ distribution ranges are changing, and species are migrating to other, more favorable, habitats, leaving places vacant. Activist movements sometimes use clever plays on words to dramatize the situation, leaving an ambiguity between species that have disappeared from a place because ecological conditions have changed, and extinct species – that is, those that are extinct for good.
Delord (2010) points out that “while there is only one ‘way’ of dying for the higher organisms that we are (whatever the causes of death), species can become extinct in several different ways”. He thus distinguishes four different ways:
– demographic extinction, that is, the pure and simple disappearance of the species from the face of the Earth. Its genetic material disappears forever;
– hybridization with another interbreeding population. This is the case, for example, for a species of fish in Lake Geneva (whitefish) (Henry 2001). In this context, the genetic material is largely preserved;
– transformation into a new species in response to ecological or genetic changes, resulting in the appearance of an apomorphic trait
1
; this type of extinction is also called “pseudo-extinction”;
– the extinction of a species that gives rise to two or more daughter species through allopatric or sympatric speciation processes.
In the first and second cases, the accounting balance of species is negative since more species disappear than appear. In the last two cases, it is zero or positive. Those who speak of the erosion of biodiversity are particularly concerned with the first two types of extinction, which cause a decline in biodiversity and marginalize the others, even though species creation is still ongoing (see Chapter 5).
1.5. Are the indicators reliable?
Since it is impossible to capture the totality of biodiversity, we are reduced to using indicators that are supposed to be representative of the whole – which have their advantages and drawbacks.
With regard to biodiversity loss, the species metric is most commonly used. It is a simple indicator, but the typological species which is most commonly used is an artificial category, representative of another era of biology, when only morphological description was available for identifying species. The typological species, it must be emphasized, is therefore not equivalent to the biological species, which is a population of interbreeding individuals (Chapter 2), and it does not provide any information about its functional role in the ecological systems. Confusion often arises between the different definitions of species, in particular, with the paleontological species (Chapter 3). Despite all these reservations, the typological species remains very popular in the absence of other indicators that are as practical from a utility point of view. However, we will see that this metric has given rise to much debate in terms of its representativeness (Arnould 2006).
The species metric is simple to use, but it does not provide information on a parameter of interest to ecologists: the relative abundance of species. In the past, this question was addressed using the Preston and Motomura models, which empirically demonstrated the existence of an apparent statistical distribution of abundances. Currently, the concept of equitability is preferred, which measures the distribution of relative abundance among species inventoried in a given system (Gosselin 2014). Scientists have spent a great deal of time developing various indices that are supposed to be more informative than others, but whose operational utility has proven to be quite limited.
Box 1.2.The New Zealand paradox (Vellend 2017)
Since the arrival of Homo sapiens in New Zealand around the 13th century, the number of plant species has doubled from about 2,000 to 4,000. On an island where there were no land mammals except a few species of bat, there are now more than two dozen. So objectively, biological diversity has increased, at least for these two groups! And yet New Zealand is often cited as experiencing a biodiversity crisis with species disappearing at an alarming rate. These seemingly paradoxical facts raise the question of whether or not the naturalization of imported species is a natural biological phenomenon or a negative human activity. In the latter case, should we also consider that birds, which are known to transport species over long distances, also have a negative impact on biodiversity? This also raises the question of the role of zoochory.
The extreme attention paid to species can make us forget that they live in a habitat (an ecological system) that is itself subject to the constraints of the climatic and anthropogenic environment. In other words, there is no species without its habitat, and the transformation of habitats, whether under anthropic or climatic constraints, is always at the origin of modifications in the distribution of species, and therefore of their presence or disappearance in a monitoring site. Nevertheless, we do not have indicators for habitats that are as simple as the typological species to quantify biodiversity. The ecosystem, a founding concept of ecology, is, according to its original definition, not spatialized. Subsequently, there has been a tendency to make it a structured whole, which it is not, because the composition and structure of an ecosystem are, by nature, evolving. As a result, every ecological system is slightly different from its neighbor, so it is difficult to identify general laws in ecology. It is said that ecology is contingent, that is, it depends not only on factors on a global scale but also on local factors, so that each region, or even each territory, has its climatic and evolutionary history. Each region also has its own history of humans’ relationship with nature. As with genetics, each region can be considered to have its own “ecological footprint” that must be taken into account.
Genetic diversity, on the other hand, is a world in full exploration that is changing the way we think about taxonomy. It is in fact the only means of accessing the diversity of microorganisms, and the development of environmental DNA techniques (barcoding) is opening up new perspectives for the study and monitoring of biodiversity. This would be a way to rapidly identify all the species present in a given environment, by searching for their genetic “traces” in a simple sample taken in situ (water, sediment, etc.). However, the methods need to be refined and the necessary data banks need to be available. Recent developments nevertheless point to a real revolution in inventorying.
Upon counting the number of extinct species, we noticed that all things considered, those attributable to humans were relatively limited. This is probably still too many, but the fact remains that it is not a hecatomb, and by no means a mass extinction! We then became interested in the capacity of species to maintain viable populations. This is how the notion of demographic decline emerged: although decline does not manifest itself in the form of species extinction, it does exist to the extent that the numbers of certain species are declining, which means that they are no longer in good ecological conditions and could potentially become extinct if this situation persists. Categories have been created according to the degree of “threats” to species, using population size as a measure. These are, for example, the IUCN Red Lists that are often referred to, in which each listed species is ranked on a scale of vulnerability. It should be noted, however, that these lists only concern a limited number of species, with the bias that these species are not selected at random. They are those in which we have a particular interest and for which we have information.
1.6. Protecting what?
Talking about protecting biodiversity in general gives the illusion that we are addressing the entire living fabric of the planet. Far from it! In reality, we need to distinguish three levels.
The first level is that of species that can be called charismatic or emblematic, among which we will find many vertebrates, as well as certain invertebrates (butterflies, mollusks) and plants which, for ethical or, esthetic reasons, or more prosaically, because they are species of interest to collectors, will receive more attention. These are the species that will most often be included in the IUCN Red Lists because information about them is available.
The second level concerns species that are not talked about or that we do not want to talk about, which are sometimes referred to as ordinary biodiversity. For example, the tapeworm is clearly declining in many countries, but no one pays attention to it. And the truth is also that there is little interest in the state of spider populations, which are of no immediate interest to us and for which, it must be admitted, there are not many lawyers to defend them. Let us face it, we have no empathy for mosquitoes or cockroaches! So there seem to be a number of species that we can say we are, at best, indifferent to, or sometimes even downright hostile to. Let us think about the different phobias. For these species, the information concerning the state of the populations is often rare and fragmentary.
Finally, there is the submerged part of the biodiversity iceberg, the whole world of microorganisms that we are only just beginning to explore. This is an invisible world that does not lend itself well to our classification systems and that baffles us because of its extraordinary capacity to adapt. A world without which all life on Earth would be impossible, because it is the microorganisms that recycle dead matter to release the mineral elements that are taken up by plants. Without them, the cycle of life would be interrupted for lack of ammunition! It is also a world that worries us because, it must be said, they are responsible for the epidemics and pandemics that decimate human populations, a world that strikes by surprise and a world that we have little control over. We actually have little empathy and a lot of apprehension for this universe that we hardly know, and we have learned to be wary of it in particular.
This means that, in reality, when we use the expression “protect biodiversity”, we are only talking about a limited number of species that we, as humans, have a self-interested and selective view of, due to cultural and emotional considerations. This systematic bias should encourage us to have a little courtesy when we talk about the planet being in danger. The disappearance of the polar bear is highly regrettable from an ethical point of view but is of little importance to the functioning of the planet. It is microorganisms that ensure the permanence of the great biogeochemical cycles, not the great charismatic predators. The disappearance of the dinosaurs did not mean the disappearance of life on Earth.
1.7. The evolution of the concept of decline: from a structural to a functional approach
Although some precursors had already drawn attention to the fact that humans were recklessly modifying nature, the first concerns about the gradual decline of biodiversity appeared in the 19th century, when it became clear that some bird species had disappeared permanently from the face of the Earth. These are the emblematic examples of the dodo, the American migratory pigeon or the great auk. In all these cases, hunting was the cause of extinction, thus testifying to humans’ responsibility. Whether these extinctions were interpreted as the loss of an evolutionary legacy or as an attack on the creator’s work, the question subsequently aroused great interest and paleontologists contributed to extending the list of extinct species by highlighting the disappearance of many endemic species in the Indo-Pacific islands. Here, again, the accused were humans and hunting, as well as humans’ commensal species (dogs, cats, rats, etc.).
The emergence and rapid spread of the concept of biodiversity at the end of the 20th century was partly due to the fact that it was thought that a way could be found to quantify the impact of humans on nature by making an inventory of the living world and, by the same token, the list of extinct species. In the context of this accounting approach, ecology has preferred inventories and developed relatively simple monitoring tools, namely the presence/absence of species or the richness of populations (the number of species present at a given moment in an ecological system). It is indeed on the subject of species losses that activist movements have communicated widely in recent decades.
